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Xylene and Hazardous Waste SitesThis public health statement tells you about xylene and the effects of exposure to it. The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. When a substance is released either from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. Such a release does not always lead to exposure. You can be exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact. If you are exposed to xylene, many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health. Find Specific Chemical Information Fast![]() Xylene FAQs and Public Health Information
1.1 What is xylene?In this report, the terms xylene, xylenes, and total xylenes will be used interchangeably. There are three forms of xylene in which the methyl groups vary on the benzene ring: meta-xylene, ortho-xylene, and para-xylene (m-, o-, and p-xylene). These different forms are referred to as isomers. Drawings of the three different isomers are shown in Chapter 4. The term total xylenes refers to all three isomers of xylene (m-, o-, and p-xylene). Mixed xylene is a mixture of the three isomers and usually also contains 6-15% ethylbenzene. Xylene is also known as xylol or dimethylbenzene. Xylene is primarily a synthetic chemical. Chemical industries produce xylene from petroleum. Xylene also occurs naturally in petroleum and coal tar and is formed during forest fires, to a small extent. It is a colorless, flammable liquid with a sweet odor. Xylene is one of the top 30 chemicals produced in the United States in terms of volume. It is primarily used as a solvent (a liquid that can dissolve other substances) in the printing, rubber, and leather industries. Along with other solvents, xylene is also widely used as a cleaning agent, a thinner for paint, and in varnishes. Xylene is used, to a lesser extent, as a material in the chemical, plastics, and synthetic fiber industries and as an ingredient in the coating of fabrics and papers. Isomers of xylene are used in the manufacture of certain polymers (chemical compounds), such as plastics. Xylene is found in small amounts in airplane fuel and gasoline. Xylene evaporates and burns easily. Xylene does not mix well with water; however, it does mix with alcohol and many other chemicals. Most people begin to smell xylene in air at 0.08-3.7 parts of xylene per million parts of air (ppm) and in water at 0.53-1.1 ppm. If you are concerned about Xylene fumes, toxic black mold, toxins from cigarette smoke, or if you would like to know which of over 400 volatile organic compounds like Xylene may be contaminating your indoor air, I recommend you easily and accurately test your indoor air using a high quality indoor air quality test kit 1.2 What happens to xylene when it enters the environment?Xylene is a liquid, and it can leak into soil, surface water (creeks, streams, rivers), or groundwater. Xylene can enter the environment when it is made, packaged, shipped, or used. Most xylene that is accidentally released evaporates into the air, although some is released into rivers or lakes. Xylene can also enter soil, water, or air in large amounts after an accidental spill or as a result of an environmental leak during storage or burial at a waste site. Since xylene evaporates easily, most xylene that gets into soil and water (if not trapped underground) is expected to go into the air where it is broken down by sunlight into other less harmful chemicals within a couple of days. For this reason, xylene is rarely found in high concentrations in topsoil or surface water (river, creeks) unless there has been a recent spill or continuing source of contamination. Any xylene that does not evaporate quickly from soil or water is broken down by small organisms. Only very small amounts are taken up by plants, fish, and birds. Xylene below the soil surface may travel down through the soil and enter underground water (groundwater). Xylene may remain in groundwater for several months before it is finally broken down by small organisms. If a large amount of xylene enters soil from an accidental spill, a hazardous waste site, or a landfill, it may travel through the soil and contaminate drinking water wells. 1.3 How might I be exposed to xylene?Xylene is primarily released from industrial sources, in automobile exhaust, and during its use as a solvent. Hazardous waste disposal sites and spills of xylene into the environment are also possible sources of exposure. You are most likely to be exposed to xylene by breathing it in contaminated air. Typical levels of xylene measured in outdoor air in the United States range from 1 to 30 parts of xylene per billion parts of air (a part per billion [ppb] is one thousandth of a part per million [ppm]; one ppm equals 1,000 ppb). Typical levels of xylene measured in indoor air range from 1 to 10 ppb. Xylene is sometimes released into water and soil as a result of the use, storage, and transport of petroleum products. Little information exists about the amount of xylene in surface water and soil. However, levels of xylene in contaminated groundwater have been reported to be as high as 10,000 ppb. You may be exposed to xylene by drinking or eating xylene-contaminated water or food. Xylene is not commonly found in drinking water. When it is, the levels of xylene are typically below 2 ppb. Xylene has been found in many types of foods at levels ranging from 1 to 100 ppb. You may also come in contact with xylene from a variety of consumer products, including gasoline, paint, varnish, shellac, rust preventives, and cigarette smoke. Breathing vapors from these types of products can expose you to xylene. In some cases, indoor levels of xylene can be higher than outdoor levels, especially in buildings with poor ventilation. Skin contact with products containing xylene, such as solvents, lacquers, paint thinners and removers, and pesticides may also expose you to xylene. Besides painters and paint industry workers, others who may be exposed to xylene include biomedical laboratory workers, distillers of xylene, wood processing plant workers, plastic composite manufacturing, semiconductor manufacturing industry, automobile garage workers, metal workers, petrochemical manufacturing, and furniture refinishers. Intalagio printing and Silk-Screen Printing are also activities that may result in Xylene exposure. Workers who routinely come in contact with xylene-containing solvents in the workplace are the population most likely to be exposed to high levels of xylene. List of Household Products Containing XyleneThe below list of household products containing Xylene includes: Brand / Category / Form / and Percent Xylene. Other synonyms and keywords which may indicate the presence of Xylene as an ingredient of common household products are as follows: Xylenes (mixture of 1,3,4-xylene, 1,3,5-xylene, and 1,3,6-xylene); Benzene, dimethyl; Dimethylbenzene; Violet 3; Xylene, mixed isomers, pure; Xylenes (mixed)
1.4 How can xylene enter and leave my body?Xylene is most likely to enter your body when you breathe xylene vapors. Less often, xylene enters the body through the skin following direct contact. It is rapidly absorbed by your lungs after you breathe air containing it. Exposure to xylene may also take place if you eat or drink xylene-contaminated food or water. The amount of xylene retained ranges from 50 to 75% of the amount of xylene that you inhale. Physical exercise increases the amount of xylene absorbed by the lungs. Absorption of xylene after eating food or drinking water containing it is both rapid and complete. Absorption of xylene through the skin also occurs rapidly following direct contact with xylene. Absorption of xylene vapor through the skin is estimated to be only 12% of the amount absorbed by the lungs. At hazardous waste sites, the most likely ways you can be exposed are: breathing xylene vapors, drinking well water contaminated with xylene, and direct contact of the skin with xylene. Xylene passes into the blood soon after entering the body. In people and laboratory animals, xylene is broken down into other chemicals especially in the liver. This process changes most of the xylene that is breathed in or swallowed into a different form that is more water soluble and is rapidly removed from the body in urine. Some unchanged xylene also leaves in the breath from the lungs within a few seconds after xylene is absorbed. One of the breakdown products of xylene, methylbenzaldehyde, is harmful to the lungs of some animals. This chemical has not been found in people exposed to xylene. Small amounts of breakdown products of xylene have appeared in the urine of people as soon as 2 hours after breathing air containing xylene. Usually, most of the xylene that is taken in leaves the body within 18 hours after exposure ends. Storage of xylene in fat or muscle may prolong the time needed for xylene to leave the body. 1.5 How can xylene affect my health?Scientists use many tests to protect the public from harmful effects of toxic chemicals and to find ways for treating persons who have been harmed. One way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify health effects such as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals. Scientists have found that the three forms of xylene and xylene mixtures have very similar effects on health. No health effects have been noted at the background levels that people are exposed to on a daily basis. Short-term exposure of people to high levels of xylene can cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; impaired function of the lungs; delayed response to a visual stimulus; impaired memory; stomach discomfort; and possible changes in the liver and kidneys. Both short- and long-term exposure to high concentrations of xylene can also cause a number of effects on the nervous system, such as headaches, lack of muscle coordination, dizziness, confusion, and changes in one's sense of balance. People exposed to very high levels of xylene for a short period of time have died. Most of the information on health effects in humans exposed for long periods of time is from studies of workers employed in industries that make or use xylene. Those workers were exposed to levels of xylene in air far greater than the levels normally encountered by the general population. Many of the effects seen after their exposure to xylene could have been caused by exposure to other chemicals that were in the air with xylene. Results of studies in animals indicate that large amounts of xylene can cause changes in the liver and harmful effects on the kidneys, lungs, heart, and nervous system. Short-term exposure to very high concentrations of xylene causes death in animals, as well as muscular spasms, incoordination, hearing loss, changes in behavior, changes in organ weights, and changes in enzyme activity. Long-term exposure of animals to low concentrations of xylene has not been well studied, but there is some information that long-term exposure of animals can cause harmful effects on the kidney (with oral exposure) or on the nervous system (with inhalation exposure). Information from animal studies is not adequate to determine whether or not xylene causes cancer in humans. Both the International Agency for Research on Cancer (IARC) and EPA have found that there is insufficient information to determine whether or not xylene is carcinogenic and consider xylene not classifiable as to its human carcinogenicity. Exposure of pregnant women to high levels of xylene may cause harmful effects to the fetus. Studies of unborn animals indicate that high concentrations of xylene may cause increased numbers of deaths, decreased weight, skeletal changes, and delayed skeletal development. In many instances, these same high concentrations also cause damage to the mothers. The higher the exposure and the longer the exposure to xylene, the greater the chance of harmful health effects. 1.6 How can xylene affect children?This section discusses potential health effects in humans from exposures during the period from conception to maturity at 18 years of age. Children might be exposed to xylenes by inhaling fumes of gasoline or of paints or other products containing xylene as a solvent. Although no studies are available, it is likely that exposed children would be similar to adults in the uptake of xylenes by breathing or swallowing or through the skin. The effects of xylenes have not been studied in children, but it is likely that they would be similar to those seen in exposed adults. Although there is no direct evidence, children may be more sensitive to acute inhalation exposure than adults because their narrower airways would be more sensitive to swelling effects (a reason that women may be more sensitive than men). There are no conclusive studies showing developmental effects of xylenes in humans. However, animal studies showed that xylene absorbed by the mother can cross the placenta and reach the fetus. The unborn animals may have reduced body weight and delayed bone mineralization when the mother is exposed to toxic levels of xylene. Some animal studies have shown that newborn babies that were exposed to xylene during pregnancy have problems after birth with motor coordination and spatial navigation. In general, these developmental effects occur at exposure levels much higher than those typically seen in the background environment, levels high enough to also harm the mother. 1.7 How can families reduce the risk of exposure to xylene?If your doctor finds that you have been exposed to substantial amounts of xylene, ask whether your children might also have been exposed. Your doctor might need to ask your state health department to investigate. Exposure to xylene as solvents (in paints or gasoline) can be reduced if the products are used with adequate ventilation and if they are stored out of the reach of small children. Sometimes older children sniff household chemicals in attempt to get high. Talk with your children about the dangers of sniffing xylene. If products containing xylene are spilled on the skin, then the excess should be wiped off and the area cleaned with soap and water. 1.8 Is there a medical test to determine whether I have been exposed to xylene?Medical tests are available to determine if you have been exposed to xylene at higher-than-normal levels. Confirmation of xylene exposure is determined by measuring some of its breakdown products eliminated from the body in the urine. These urinary measurements will determine if you have been exposed to xylene. There is a high degree of agreement between exposure to xylene and the levels of xylene breakdown products in the urine. However, a urine sample must be provided very soon (within hours) after exposure ends because xylene quickly leaves the body. Alcohol or aspirin may produce false positive test results. Medical tests have been developed to measure levels of xylene in blood by the National Center for Environmental Health and in exhaled breath by EPA's Total Exposure Assessment Methodology. These tests may be available in certain doctors' offices. Available tests can only indicate exposure to xylene; they cannot be used to predict which health effects, if any, will develop. 1.9 What recommendations has the federal government made to protect human health?The federal government develops regulations and recommendations to protect public health. Regulations can be enforced by law. The EPA, the Occupational Safety and Health Administration (OSHA), and the Food and Drug Administration (FDA) are some federal agencies that develop regulations for toxic substances. Recommendations provide valuable guidelines to protect public health, but cannot be enforced by law. The Agency for Toxic Substances and Disease Registry (ATSDR) and the National Institute for Occupational Safety and Health (NIOSH) are two federal organizations that develop recommendations for toxic substances. Regulations and recommendations can be expressed as "not-to-exceed" levels, that is,levels of a toxic substance in air, water, soil, or food that do not exceed a critical value that is usually based on levels that affect animals; they are then adjusted to levels that will help protect humans. Sometimes these not-to-exceed levels differ among federal organizations because they used different exposure times (an 8-hour workday or a 24-hour day), different animal studies, or other factors. Recommendations and regulations are also updated periodically as more information becomes available. For the most current information, check with the federal agency or organization that provides it. Some regulations and recommendations for xylene include the following: The EPA estimates that, for an adult of average weight, exposure to 7 milligrams of xylene per liter (mg/L or ppm) of water each day for a lifetime (70 years) is unlikely to result in harmful noncancerous health effects. Exposure to 40 ppm (or mg/L) xylene in water for 1 or 10 days is unlikely to present a health risk to a small child. The EPA has proposed a recommended maximum level of 10 ppm xylene in drinking water. To protect people from the potential harmful health effects of xylene, EPA regulates xylene in the environment. EPA has set a legally enforceable maximum level of 10 mg/L (equal to 10 ppm) of xylene in water that is delivered to any user of a public water system. OSHA regulates levels of xylene in the workplace. The maximum allowable amount of xylene in workroom air during an 8-hour workday in a 40-hour workweek is 100 ppm (435 mg/m3). These regulations match the recommendations (not legally enforceable) of the American Conference of Governmental Industrial Hygienists. NIOSH has recommended an exposure limit (not legally enforceable) of 100 ppm of xylene averaged over a workday up to 10 hours long in a 40-hour workweek. NIOSH has classified xylene exposures of 900 ppm (3,906 mg/m2) as immediately dangerous to life or health. EPA regulations require that a spill of 100 or more pounds of mixed xylenes or p-xylene or 1,000 pounds or more of m-xylene or o-xylene (new or used solvents) be reported to the Federal Government National Response Center. 1.10 Where can I get more information?If you have any more questions or concerns, please contact your community or state health or environmental quality department or: Agency for Toxic Substances and Disease Registry Information line and technical assistance: Phone: 888-422-8737 ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances. To order toxicological profiles, contact: National Technical Information Service 1.11 ReferencesAgency for Toxic Substances and Disease Registry (ATSDR). 2005. Toxicological profile for Xylene. (Draft for Public Comment). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
1.12 Xylene MSDS InformationA free Xylene MSDS is coming very soon. In the mean time you may find much of the Xylene Material Safety Data Sheet information in the below toxicological information.
1.13 Complete Xylene Toxicological InformationHuman Health Effects from Xylene Exposure
Emergency Medical Treatment for Xylene Exposure
Animal Toxicity Studies
Metabolism/Pharmacokinetics
Pharmacology of Xylene
Environmental Fate & Exposure to Xylene
Xylene Environmental Standards & Regulations
Xylene Chemical/Physical Properties
Xylene Chemical Safety & Handling
Xylene Occupational Exposure Standards
Xylene Manufacturing/Use Information
Xylene Laboratory Methods
Special References
Xylene Synonyms and Identifiers
XYLENE Human Health Effects:
Toxicity Summary: After inhalation exposure the retention in the lungs is about 60% of the inhaled dose. Xylene is efficiently metabolized. More than 90% is biotransformed to methylhippuric acid, which is excreted in urine. Xylene does not accumulate significantly in the human body. Acute exposure to high concentrations of xylene can result in CNS effects and irritation in humans. ... The chronic toxicity appears to be relatively low in laboratory animals. There is suggestive evidence, however, that chronic CNS effects may occur in animals at moderate concentrations of xylene. Xylene does not appear to be a mutagen or carcinogen. The critical end point is developmental toxicity ... The xylene isomers are of moderate to low toxicity for aquatic organisms. ... The acute toxicity of xylene to birds is low.
Evidence for Carcinogenicity: Evaluation: There is inadequate evidence in humans for the carcinogenicity of xylenes. There is inadequate evidence in experimental animals for the carcinogenicity of xylenes. Overall classification: Xylenes are not classifiable as to their carcinogenicity to humans (Group 3). CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Orally administered technical xylene mixtures did not result in significant increases in incidences in tumor responses in rats or mice of both sexes. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Inadequate. A4; Not classifiable as a human carcinogen. /Xylene (o-,m-, & p- isomers)/
Human Toxicity Excerpts: Xylene is a central nervous system depressant that produces lightheadedness, nausea, headache, and ataxia at low doses and confusion, respiratory depression, and coma at high doses. Above 200 ppm, xylene causes conjunctivitis, nasal irritation, and sore throats; it is a potent respiratory irritant at high concentrations. ... Xylene produces a defating dermatitis with prolonged cutaneous exposure. Transient mildly elevated hepatic aminotransferase levels and reversible renal failure were reported in an estimated 10,000 ppm xylene exposure occurring during the painting of a poorly ventilated ship compartment. Two men were comatose and one was dead on arrival after this prolonged exposure over 18 hours. The survivors developed no long-term sequelae. The contributions of hypoxia and a toluene solvent could not be quantitated. In workers exposed to organic solvents (acetone, benzene, toluene, ethyl acetate, butyl acetate, xylene, gasoline, and turpentine) the incidence of chronic bronchitis was higher, and the volume of expiratory air was lower than in normal control subjects. In smokers the incidence was higher than nonsmokers of /exposed and nonexposed/ groups. Smoking increases risk of chronic bronchitis in ... subjects /exposed to organic solvents/. Dermal application of xylene caused a 20-40% decr in electrical impedance of human skin. CNS DEFECTS WERE MORE COMMON IN CHILDREN OF MOTHERS EXPOSED TO ORG SOLVENTS & DUSTS DURING PREGNANCY. HYDRANENCEPHALY OCCURRED IN CHILDREN WHOSE MOTHERS HAD BEEN EXPOSED TO THE SOLVENTS TOLUENE, XYLENE, & WHITE SPIRIT DURING MANUFACTURE OF RUBBER PRODUCTS. Women are liable to suffer from menstrual disorders (menorrhagia, metrorrhagia). It has been reported that female workers exposed to ... xylene in concn which periodically exceeded the exposure limits were also affected by pathological pregnancy conditions (toxicosis, danger of miscarriage, hemorrhage during child birth) and infertility. Mixed xylenes ... at exposures of one to four times TLV (threshold limit value) /SRP: 400 ppm/ levels were used. Subjective reports of irritation, as well as polygraph records of eyeblink and respiration rate were recorded during 30 min exposures. Psychomotor tests were administered before, during, and after exposure. Both a higher incidence of eye irritation and rate of eyeblink were reported by exposed subjects compared to controls, but the effects were mild. There were no significant differences in respiration rates or in tests of psychomotor function. USING A STANDARDIZED INTERVIEW SCHEDULE, OCCUPATIONAL EXPOSURE TO ORG SOLVENTS WAS INVESTIGATED IN 61 MALE PATIENTS WITH DIAGNOSIS OF NON-HODGKIN'S LYMPHOMA. RESULTS INDICATE A RELATION BETWEEN EXPOSURE TO ORG SOLVENTS & SUPRADIAPHRAGMATIC PRESENTATION OF NON-HODGKIN'S LYMPHOMA. ELEVEN REPORTED EXPOSURE TO XYLENE. HOWEVER, IN MOST CASES EXPOSURE TO MORE THAN ONE SOLVENT WAS REPORTED. For the period 1961-80, 118 cases of industrial gassings caused by the solvents methlyene chloride, xylene, toluene and styrene were reported to Her Majesty's Factory Inspectorate. The data were collated and analyzed according to the predetermined criteria of age, sex, mode and circumstances of use, clinical effect and outcome. The study shows the /SRP: CNS depressant/ effect of these solvents and underlines the dangers of their use in confined spaces. Symptoms were most commonly attributable to the nervous and respiratory system. Disturbances of memory, mood, equilibrium and sleep that occurred simultaneously with headache and indigestion, were experienced more frequently among women working in histology who had daily exposure to formaldehyde, xylene and toluene than in unexposed female clerical workers in the same hospitals. Neurobehavioral symptoms were accompanied by irritation of the eyes, upper air ways and trachea. Formaldehyde exposure correlated better with neurobehavioral symptoms and with respiratory and mucous membrane symptoms than did exposure to xylene/toluene or to other agents. ... Inhalation of xylenes at concn of 435-1300 mg/cu m for 15 min to 6 hr/day for 4 days results in CNS disturbances including changes in numerative ability, reaction time, short-term memory and electroencephalograph. An adverse health effect disturbance to equilibrium has been observed in humans. ... This effect has been correlated with blood concn ... of 30 umol/l (equivalent to 318 ug/100 ml) ... . Mixtures of organic solvents, which include xylenes, have been implicated as the cause of lens change in car painters. ... Among nine pregnancies producing offspring with caudal regression syndrome five mothers had exposure to fat solvents. These included ... xylene. The concentration of xylene present in the blood, its serum or plasma, that has been reported to cause death, or is so far above reported therapeutic or toxic concentrations that one can judge that it might cause death in humans is 3-40 ug/ml. The correlation between xylene exposure and urinary excretion of methyl hippuric acid (MHA) was studied in 40 workers (35 men, 5 women) employed in the paint industry. Subjects were exposed primarily to xylene although exposure to 11 other solvents was possible. Personal sampling showed 8-hr TWA's for xylene ranged from 0-865 mg/cu m with a median exposure of 69 mg/cu m. Urine was collected over one 24-hr period for each worker. Personal air samples were collected for each worker over the course of a complete workday. MHA excretion was linearly correlated to the 8-hr TWA for xylene exposure after adjustment for body weight. The total amount of MHA excreted in the urine over 24 hr showed virtually the same correlation to xylene exposure (r = 0.84) as the MHA excretion during the latter part of the workshift (r = 0.81, sampling time 4-5 hr) among 37 workers exposed to 8-hr TWA xylene concentrations of 0-200 mg/cu m. Vapor irritates eyes and mucous membranes and may cause dizziness, headache, nausea, and mental confusion. Liquid irritates eyes and mucous membranes. Swallowing or absorption through skin would cause poisoning. Prolonged exposure to skin contact may result in dermatitis. Serum concentrations of liver enzymes were determined for Swedish paint industry workers exposed to a mixture of organic solvents including xylene. Mean xylene exposure for 44 individuals was 82 mg/cu m (19 ppm) with a range of 1 to 6070 mg/cu m; five workers were exposed to a mean concentration of 865 mg/cu m (199 ppm). Serum alanine aminotransferase, aspartate aminotransferase, ornithine carbamoyltransferase, and gamma-glutamyltransferase activities were not elevated by these exposures. ... Occupational experience reveals complaints of dermatitis, eczema, and irritation of the eyes and respiratory tract but rarely serious illness. It is likely that untoward effects on the hematopoietic system reported in the past as being caused by xylene resulted from benzene contamination of commercial xylene. Six volunteers were able to detect the odor of mixed xylenes at a concentration of 60 mg/cu m; four could detect 6 mg/cu m, but none could detect 0.6 mg/cu m. The odor threshold was calculated as 4.5 mg/cu m or about 1 ppm for a 10-sec exposure. In a 15-min exposure period, the only common sign of discomfort at 2000 mg/cu m (460 ppm) was eye irritation in four of six subjects. Some transitory olfactory fatigue occurred, with recovery in 10 min. Exposure of volunteers to technical xylene by inhalation caused irritation of the airways; very high accidental exposure caused pneumonitis. Ingestion of xylene caused irritation of the gastrointestinal tract. Repeated, prolonged exposure to fumes may produce conjunctivitis of the eye and dryness of the nose, throat, and skin. Direct liquid contact may result in flaky or moderate dermatitis. Inhalation of vapors may cause CNS excitation then depression, characterized by paresthesia, tremors, apprehension, impaired memory, weakness, nervous irritation, vertigo, headache, anorexia, nausea, and flatulence, and may lead to anemia and mucosal hemorrhage. Clinically, no bone marrow aplasia, but hyperplasia, moderate liver enlargement, necrosis, and nephrosis may occur. During an informal study in 1973 it was noted that approx 1/3 of patients with congenital heart disease lived in a small area in the Tucson Valley. In 1981 groundwater for nearly identical area was found to be contaminated with trichloroethylene and to a lesser extent with dichloroethylene and chromium. Contamination probably began during the 1950s. Affected wells were closed after discovery of contamination. This sequence of events allowed investigation of the prevalence of congenital heart disease in children whose parents were exposed to the contaminated water area as compared with children whose parents were never exposed to the contaminated water area. The contaminated water area contained 8.8% of the Tucson Valley population and 4.5% of the labor force. Using their case registry, the authors interviewed parents of 707 children with congenital heart disease who, between 1969 and 1987, 1) conceived their child in the Tucson Valley, and 2) spent the month before the first trimester and the first trimester of the case pregnancy in the Tucson Valley. Two random dialing surveys showed that only 10.5% of the Tucson Valley population had ever had work or residence contact, or both, with the contaminated water area, whereas 35% of parents of children with congenital heart disease had had such contact (p < 0.005). The prevalence of congenital cardiac disease (excluding syndromes, children with atrial tachycardia or premature infants with patent ductus arteriosus) in the Tucson Valley was 0.7% of live births and with syndromes was calculated to be 0.82%. The odds ratio for congenital heart disease for children of parents with contaminated water area times that for those without contact (p < 0.005) and decr to near unity for new arrivals in the contaminated water area after well closure. The proportion of infants with congenital heart disease as compared with the number of live births was significantly higher for resident mothers in the contaminated water area than for mothers with no exposure. No other environmental agent could be identified that was localized to the contaminated water area, but one could have been missed. The data show a significant assoc but not a cause and effect relation between parental exposure to the contaminated water area and an incr proportion of congenital heart disease among live births as compared with the proportion of congenital heart disease among live births for parents without contaminated water area contact. The quantitative relationship between exposure to xylene vapor and urinary excretion in methylhippuric acid isomers were studied in the second half of a working wk. The participants in the study were 121 male workers engaged in dip-coating of metal parts who were predominantly exposed to three xylene isomers. The intensity of exposure measured by diffusive sampling during an 8-hr shift was such that the geometric mean vapor concn was 3.8 ppm for xylenes (0.8 ppm for o-xylene, 2.1 ppm for m-xylene, and 0.9 ppm for p-xylene), 0.8 ppm for toluene, and 0.9 ppm for ethylbenzene. Urine samples were collected at the end of the shift and analyzed for metabolites by HPLC. The statistical analysis showed that there is a linear relationship between the intensity of exposure to xylenes and the concn of methylhippuric acid in urine, that the regression line passes very close to the origin, and that the increment in observed (i.e., noncorrected) methylhippuric acid concn as a function of incr xylene concn was 17.8 mg/ppm. Further exam on the basis on individual xylene isomers showed that the slopes of the regression lines for o- and m-isomers were similar (i.e., 17.1 and 16.6 mg/L/ppm, respectively), whereas that for p-xylene was larger (21.3 mg/L/ppm).
Human Toxicity Values: LDLo Human oral 50 mg/kg
Skin, Eye and Respiratory Irritations: Xylene vapor may cause irritation of the eyes, nose, and throat. At high concentrations, xylene vapor may cause severe breathing difficulties which may be delayed in onset. Repeated or prolonged exposure ... may cause a skin rash. Vapor irritates eyes and mucous membranes and may cause dizziness, headache, nausea, and mental confusion. Liquid irritates eyes and mucous membranes.
Medical Surveillance: EMPLOYEES EXPOSED TO XYLENE SHOULD UNDERGO COMPREHENSIVE PREPLACEMENT & BIENNIAL MEDICAL CHECKUPS. AIR & BIOLOGIC MONITORING PROGRAMS SHOULD BE ESTABLISHED & EVALUATED REGULARLY. History and examination /of workers exposed to xylene/ should be directed toward, but not limited to, the incidence of headaches, nausea, or other GI disturbances, dizziness, and of alc consumption; ... attention should be focused on complaints and evidence of eye, mucous membrane, or skin irritation; ... examination /should/ include a complete blood count, a routine urinalysis, and ... liver function tests.
Probable Routes of Human Exposure: Xylene can affect the body if it is inhaled, if it comes in contact with the eyes or skin, or if it is swallowed. THE ADVANTAGES & DISADVANTAGES OF USING SOFT CONTACT LENSES (IN HUMANS) IN ENVIRONMENTS WITH FUMES FROM SOLVENTS OR SPLASHES OF STRONG ACIDS & ALKALIS WERE STUDIED EXPERIMENTALLY. UPTAKE OF XYLENE BY LENS MATERIALS WAS UP TO 90 TIMES THAT BY PHYSIOLOGIC SALINE, USED TO SIMULATE TEAR FLUID. WHEN EXPOSED LENSES WERE SOAKED FOR 10 & 60 MIN IN A VERY SMALL VOLUME OF SALINE THE CONCN OF SOLVENT IN THAT SALINE WAS ONLY UP TO 23 & 11%, RESPECTIVELY, OF THAT IN DIRECT EXPOSED SALINE. SOLVENTS WERE RELEASED MAINLY TO THE AIR. CONTACT LENSES WOULD LEAD TO A PROLONGED EXPOSURE BUT TO A RATHER LOW CONCN AS COMPARED TO DIRECT EXPOSURE. Exposure to organic solvent vapors was investigated in 40 unit workplaces (with 189 workers) in 16 small scale industries in north-east Japan ... in which synthetic urushi lacquer was applied to produce non-metal tableware. ... Two furniture factories were also studied. The equipment used was carbon felt dosimeters and portable PID-GC ... . ... The gas chromatography could analyze benzene-toluene xylenes within 150 seconds. ... Toluene was the major pollutant in the workplace air, with small quantities of xylenes. ... Exposure did not exceed the current occupational exposure limit in all the cases except for the two workers, who were excessively exposed due to the generation of dense vapors in automated spraying process. ... There is a broad potential for exposure both to industrial workers in the production and use of the xylenes and to the general public (via vehicle exhausts, consumer products, etc). ... Number of USA workers exposed 140,000 /Time frame not mentioned/ NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,528,018 workers (316,320 of these are female) are potentially exposed to xylenes in the US(1). An average xylene concn of 0.1 ppm was detected in the breathing zones of paint shops sampled in the US(2). Lab personnel are exposed to an average xylene concn of 0.16 ppm and material handling personnel are exposed to an average xylene concn of 1.6 ppm at hazardous waste facilities in the US(3). The 8 hour TWA exposure to xylenes for personnel at organic solvent recycling plants was measured as 1 ppm(4). A study from 1979-1987 calculated the average exposure to xylenes in paint manufacturing plants as 2.01 ppm in breathing zone locations(5). A survey of 97 autobody shops in the US reported the 8 hour TWA exposure to xylenes was 3.3 ppm for painters and 0.7 ppm for non-painting personnel(6). The 8 hour TWA for worker exposure to xylenes in a German histology laboratory and a US histology laboratory was measured as 243-295 mg/cu m and 11-315 mg/cu m respectively(7). The 8 hour TWA for worker exposure to xylenes in a US hospital laboratory was measured as 3-1700 mg/cu m(7). Occupational exposure may be through inhalation and dermal contact with this compound at workplaces where xylenes are produced or used(SRC). The general population will be exposed to xylenes largely via inhalation of ambient air, particularly in areas with heavy traffic, near filling stations and near industrial sources such as refineries(SRC). Exposure may also arise from consuming contaminated food and drinking water(SRC). An average concn of 0.37 ppb of 3- and 4-xylene was measured in blood samples collected from 60 persons in the US that are not occupationally exposed to xylenes(8). Humans are exposed to xylene primarily from air, particularly in areas with heavy traffic, near filling stations, near industrial sources such as refineries or where xylene is used as a solvent. Exposure may also arise from drinking contaminated well water near leaking underground gasoline storage tanks or from spills of petroleum products. (SRC) Benzene and xylenes are components of gasoline. The US population exposed to xylenes from petroleum related sources can be assumed to be the same as for benzene, namely: people choosing self-service at gasoline service stations 37,000,000; people living in the vicinity of gasoline service stations 118,000,000; petroleum refineries 6,597,000; urban exposure (auto emissions) 113,690,000(1). /Xylenes/
Body Burden: ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE WAS ONE OF THE AROMATICS IDENTIFIED. FOLLOWING EXPOSURE OF RABBITS TO AN ATMOSPHERE OF ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM) OR IN OTHER ORGANS.
Average Daily Intake: AIR INTAKE: (Assume typical concn 4.0 ppb) 353 ug; WATER INTAKE: (Assume typical concn 0-1 ppb) 2 ug; FOOD INTAKE: Insufficient data. (SRC)
Emergency Medical Treatment:
Emergency Medical Treatment: Animal Toxicity Studies:
Toxicity Summary: After inhalation exposure the retention in the lungs is about 60% of the inhaled dose. Xylene is efficiently metabolized. More than 90% is biotransformed to methylhippuric acid, which is excreted in urine. Xylene does not accumulate significantly in the human body. Acute exposure to high concentrations of xylene can result in CNS effects and irritation in humans. ... The chronic toxicity appears to be relatively low in laboratory animals. There is suggestive evidence, however, that chronic CNS effects may occur in animals at moderate concentrations of xylene. Xylene does not appear to be a mutagen or carcinogen. The critical end point is developmental toxicity ... The xylene isomers are of moderate to low toxicity for aquatic organisms. ... The acute toxicity of xylene to birds is low.
Evidence for Carcinogenicity: Evaluation: There is inadequate evidence in humans for the carcinogenicity of xylenes. There is inadequate evidence in experimental animals for the carcinogenicity of xylenes. Overall classification: Xylenes are not classifiable as to their carcinogenicity to humans (Group 3). CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Orally administered technical xylene mixtures did not result in significant increases in incidences in tumor responses in rats or mice of both sexes. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Inadequate. A4; Not classifiable as a human carcinogen. /Xylene (o-,m-, & p- isomers)/
Non-Human Toxicity Excerpts: /INVESTIGATORS/ ... FOUND NO ADVERSE EFFECTS ON THE HEMATOPOIETIC SYSTEM /OF THE GUINEA PIG/ AFTER SC ADMIN AT 300 MG/KG/DAY FOR 6 WK OR 700 MG/KG/DAY FOR 9 WK. OTHER REPORTS OF MYELOTOXICITY OF XYLENE ARE PROBABLY RELATED TO BENZENE CONTAMINATION. ... RABBITS EXPOSED TO BENZENE-FREE XYLENE (AT 5 MG/L, OR 1,150 PPM) FOR 40-55 DAYS HAD DECREASED RED & WHITE CELL COUNTS. RATS WERE EXPOSED TO XYLENE VAPORS COMPOSED OF THE 3 XYLENE ISOMERS, ETHYLBENZENE, TOLUENE, AROMATICS & NONAROMATICS. LC50 FOR RATS WAS 29 MG/L/4 HR (6700 PPM). CATS SUCCUMBED WITHIN 2 HR AT 41 MG/L (9500 PPM) WITH SIGNS OF CNS DAMAGE. NO DIFFERENCES FROM CONTROL ANIMALS WERE OBSERVED IN BEAGLE DOGS & RATS THAT INHALED 3.5, 2.0 OR 0.77 MG/L CONCN FOR 6 HR/DAY, 5 DAYS/WK FOR 13 WK. The embryotoxic effects of xylene were studied by exposing rats to 1000 mg/cu m of air during days 9 through 14 /of pregnancy/ ... found no teratogenic results although minor skeletal anomalies occurred. Data obtained from rodents indicates that maternal exposure to mixed xylenes or individual xylene isomers can have adverse effects on the conceptus. Fetotoxic effects were reported following maternal inhalation exposure to mixed xylenes; altered enzyme activities were also found in rat pups. Dermal application resulted in apparent changes in fetal enzyme activities, while oral treatment was followed by prenatal mortality, growth inhibition, and malformations, primarily cleft palate. Maternal inhalation of individual isomers was associated with all the above mentioned effects, with the exception of cleft palate. The o- and p- isomers appeared more hazardous to the offspring than did the m-isomer. Malformations (ie cleft palate) associated with mixed or individual isomers were primarily reported at maternally toxic doses. Thus, a clear case for a selective teratogenic effect due to the exposure to xylene has yet to be presented. EFFECTS OF COAL TAR-ASSOCIATED CHEMICALS WERE TESTED BY SINGLE TOPICAL APPLICATION (1 MG/10 G BODY WT) TO NEONATAL RATS. THE INDUCIBILITY OF XYLENE ON SKIN ARYL HYDROCARBON HYDROXYLASE (AHH) WAS 8% & ON LIVER ARYL HYDROCARBON HYDROXYLASE 10%. Male rats exposed to different concentrations of xylene for three days /exhibited/ small but statistically significant increase in cytochrome p450 content. Reduced nicotinamide adenine dinucleotide cytochrome c reductase activity and O-deethylation of 7-ethoxyresorufin in liver microsomes were detected already at an exposure level of 75 ppm. Morphological studies of livers from rats exposed to relatively high concentrations showed marked proliferation of smooth endoplasmic reticulum with little changes of the rough endoplasmic reticulum. No pathological alterations were observed. Castration of male rats influenced the response of xylene exposure only to a minor extent. Hypophysectomy alone was shown to cause significant increases in cytochrome p450 and cytochrome b5 content and epoxide hydrolase activity. Induction of cytochrome p450 dependent enzymatic activities after exposure to xylenes was reduced but qualitatively similar to that obtained with normal male rats whereas the induction of epoxide hydrolase activity was prevented. ... XYLENE WAS ADMIN ORALLY TO FEMALE WISTAR CFT STRAIN RATS. XYLENE DID NOT PROVE LETHAL UP TO THE DOSAGE OF 6 ML/KG. HOWEVER, THE MINIMUM LETHAL DOSE WAS 7 ML/KG. SYMPTOMS MANIFESTED AT FATAL DOSES WERE DULLNESS, STUPOR, ANESTHESIA, CNS DEPRESSION, & COMA. MORTALITY WAS DOSE-DEPENDENT. Xylene, a widely used industrial solvent, is a mixture of ortho-, meta-, and para- isomers. In this study, ... the effects of each isomer, as well as a commercial-grade mixture of xylenes, on two behavioral measures /were examined/: 1) Operant performance of 15 mice trained to lever-press under a DRL (differential reinforcement of low rates) 10 sec schedule, and 2) motor performance of mice on an inverted screen test. The 15 min operant sessions immediately followed 30 min exposures to solvent vapors (500 to 7000 ppm), or air, in static inhalation chambers. Ortho-, meta-, para-, and mixed xylenes produced similar biphasic effects on response rates, and concentration dependent decreases in reinforcement rates. SUBACUTE EXPOSURE OF MALE RATS TO 2000 PPM OF XYLENE, ORTHO-XYLENE, META-XYLENE, PARA-XYLENE, & ETHYLBENZENE PRODUCED DISCRETE INCREASES OF DOPAMINE & NORADRENALINE LEVELS & TURNOVER IN VARIOUS PARTS OF HYPOTHALAMUS. XYLENE ITSELF PRODUCED WIDESPREAD INCR OF DOPAMINE TURNOVER WITHIN NEOSTRIATUM & SUBCORTICAL LIMBIC FOREBRAIN. EXPOSURE 6 HR/DAY FOR 3 DAYS TO 2000 PPM INCREASED HEPATIC CYTOCHROME P450 CONCENTRATIONS & NADPH CYTOCHROME C REDUCTASE ACTIVITY IN RATS. IN KIDNEY MICROSOMES AN INCR CONCN OF CYTOCHROME P450 WAS OBTAINED. IN LUNG MICROSOMES XYLENE CAUSED A DECR IN CYTOCHROME P450 CONTENT. MALLARD EGGS WERE TREATED BY IMMERSION IN XYLENE (1% & 10%) FOR 30 SECONDS AT ROOM TEMP. XYLENE HAD NO SIGNIFICANT EFFECTS AT CONCENTRATIONS OF 10% ON EMBRYONIC WT & LENGTH WHEN COMPARED TO CONTROLS. HAMSTERS RECEIVED XYLENE TOPICALLY FOR 2 HR BETWEEN DAYS 7 & 11 & WERE KILLED AT DAY 15 OF GESTATION. FETAL SIZE & WEIGHT DECREASED & THE INCIDENCE OF PRENATAL DEATHS INCREASED. FETAL HEMORRHAGE & GASTROSCHISIS WERE ALSO NOTED. NO MALFORMATIONS WERE FOUND IN CONTROLS. PREGNANT OUTBRED ALBINO MICE RECEIVED BY GAVAGE, 3 TIMES/DAY IN COTTONSEED OIL, A XYLENE MIXT ON DAYS 6-15 OF GESTATION. THE MICE WHERE KILLED ON DAY 18. AT 3.6 ML/KG/DAY, XYLENE KILLED 12 OF 38 DAMS & CAUSED A SIGNIFICANTLY SMALLER AVG WT GAIN DURING PREGNANCY THAN DID THE COTTONSEED OIL. FETUSES FROM DAMS TREATED @ 2.4 ML/KG/DAY HAD AVG FETAL WT SIGNIFICANTLY LOWER THAN THAT OF CONTROL FETUSES. AT 2.4, 3.0, & 3.6 ML/KG/DAY XYLENE PRODUCED A SIGNIFICANTLY GREATER AVG % OF MALFORMED FETUSES THAN DID THE CONTROL. CLEFT PALATE WAS THE MAJOR MALFORMATION AT ALL 3 DOSES. WHEN BILATERAL WAVY RIBS WERE COUNTED AS A MALFORMATION, THE AVG % OF MALFORMED FETUSES INCR FROM 7.8 TO 10.5 @ 3.0 ML/KG/DAY & FROM 9.1 TO 13.4 @ 3.6 ML/KG/DAY. THUS, XYLENE (MIXED ISOMERS) IS TERATOGENIC TO MICE @ 2.4 & 3.0 ML/KG/DAY. By exposing cats for several hours to concentrations of xylene vapor which were just sublethal /the laboratory/ succeeded in producing vacuoles in the corneal epithelium which appeared to be analogous to those occurring in vacuolar keratopathy occurring in workmen from exposure to solvent vapors. Rats /exposed to/ xylene at 230, 1900, or 3360 mg/cu m for 24 hr/day from day 7-14 of pregnancy showed no maternal toxicity. However, bone formation was retarded in the fetuses at all 3 concn, and the number of nephrons with enzyme activity and the activity ... of succinic dehydrogenase, alkyl phosphatase, acid phosphatase, and glucose 6-phosphatase were decreased in fetuses at the highest concn. ... The incidence of extra ribs in fetuses increased, however, none of the concn were teratogenic. The incidence of postimplantation fetal loss increased. In rats, exposure to xylene (50 or 500 mg/cu m) resulted in embryotoxic and teratogenic effects. The brain, liver, lung, and heart were affected. The number of postimplantation losses increased by 9.7 and 168% in the 50 and 500 mg/cu m xylene group, respectively. The incidence of fetal skeletal abnormalities was increased by 62 and 177%, respectively. Rats were exposed to ... xylene at 200-800 ppm for 30 days. After exposure, changes in the dopamine, norepinephrine, serotonin, acetylcholine (ACH), CAMP, CGMP, GCBA, Gln, Asp, Tau, Gly, and Ala content of different areas of the brain were investigated. Acetylcholine in the striatum and the whole brain was reduced dose dependently by ... xylene. ... Xylene caused different changes in monoamine content ... but the changes were not dose dependent. ... Glutamine content was increased by ... xylene at 800 ppm. In rats exposed to /xylene/ by inhalation for 2 wk (5 days/wk, 6 hr/day) ... kidney 7-ethoxycoumarin O-deethylase activity was increased >200% ... /and/ liver UDP-glucuronosyltransferase activity was increased ... approx 100%. ... ... Xylene reduced the number and weight of /Agaricus bisporus/ sporophores. Kucera reports studies in chick embryos exposed for 60 to 240 minutes to a xylene atmosphere at developmental periods up to the 10 somite stage. A high malformation rate was found and nearly one-half of the defects were rumplesness, a defect resembling caudal regression syndrome. Exposure of male rats to /250-2000 ppm/ of xylene for 3 days induced, in a dose related way, the in vitro liver microsomal metabolism of antipyrine. The degree of induction was significant at an exposure level of 250 ppm and maximal (2.5-fold incr) at 2000 ppm. This incr was of the same magnitude as after phenobarbital treatment. Female rats had lower basal antipyrine metabolism than males but exhibited a greater relative incr in antipyrine metabolism following xylene exposure. ... Exposure to lower xylene levels did not produce significant alterations in antipyrine elimination half-life. ... Quail eggs were treated directly by spraying the shell with 2 or 0.05% aq suspensions of ... xylene, or indirectly by repeated ingestion by the parental quail of contaminated feed. /Xylene/ significantly acted upon the quail biotic potentials by reducing the hatching rate and the embryonic viability and increasing the fecundation rate and the weight of eggs, chickens, and adults. /Xylene/ reversed the sex ratio, so that the male birds had an advantage in number and acted more specifically on the embryonic genital development. ... Xylene at 2 mmol/kg decreased the metabolism of (14)C labeled benzene (2 mmol/kg) to phenol and other metabolites in rats. The metabolism of (14)C toluene was not inhibited by ... xylene. ... Groups of Sprague Dawley rats were exposed, by inhalation, to ... xylene (600 ppm, 2625 mg/cu m) ... for 4 wk. Increased liver weights and liver to body wt ratios were observed. ... An increase in in vitro formation of certain metabolites of all substrates was found in rats exposed to xylene. ... Xylene was a 'phenobarbital-like' inducer of rat liver microsomal cytochrome p450. In single administration studies, groups of five F344/N rats and B6C3F1 mice of each sex received 500, 1,000, 2,000, 4,000, or 6,000 mg/kg /gavage in corn oil/. Administration of xylenes caused deaths at 6,000 mg/kg in rats and mice of each sex and at 4,000 mg/kg in male rats. Clinical signs observed /from 24 hr to 2 wk/ of dosing at 4,000 mg/kg included prostration, muscular incoordination, and loss of limb movement. Tremors, prone position, and slowed breathing were recorded for mice on day 3, but all mice appeared normal by the end of the 2 wk observation period. In 14 day studies, groups of five /rats/ ... of each sex ... were administered 0, 125, 250, 500, 1,000, or 2,000 mg/kg and mice received 0, 250, 500, 1,000, 2,000, or 4,000 mg/kg. Chemical related mortality occurred only at 2,000 mg/kg in rats and 4,000 mg/kg in mice. Rats and mice exhibited shallow breathing and prostration within 48 hr following dosing at 2,000 mg/kg. These signs persisted until day 12 for rats, but no clinical signs were noted during the second wk for mice. In 13 wk studies, groups of 10 rats of each sex received 0, 62.5, 125, 250, 500, or 1,000 mg/kg, and groups of 10 mice of each sex received 0, 125, 250, 500, 1,000, or 2,000 mg/kg. No deaths or clinical signs of toxicity were recorded in rats. However, high dose male rats gained 15% less and females gained 8% less weight than did the vehicle controls. Two female mice died at the 2,000 mg/kg level. Lethargy, short and shallow breathing, unsteadiness, tremors, and paresis were observed for both sexes in the 2,000 mg/kg group within 5-10 min after dosing and lasted for 15-60 min. ... It is of importance to note that coal-based solvents (eg, xylene) have been suggested to be possible potent lymphocytic leukemogens, such as benzene, in a limited study of the relationship between lymphocytic leukemia and exposures to benzene and other solvents in the rubber industry. Available animal data on the carcinogenicity of xylene(s) are inadequate to permit an evaluation. In limited studies thus far, the individual isomers were not found genotoxic when tested in a number of short-term tests. Two laboratories tested multiple forms of xylene for their developmental toxicity hazard potential (A/D ratio) by means of the hydra assay. The three isomers, as well as a solution of mixed xylenes, all interfered with development (D) at or near to concn that also were toxic to adult (A) hydra. The development/adult ratios ranged from 1 to 2 in hydra as they had in conventional tests made in pregnant laboratory animals. Each testing laboratory concluded that xylenes were not primary development hazards but coeffective agents capable of disrupting development only at or near to concn also toxic to adults. In each instance every xylene tested interfered with the same stage or developmental sequence and in a concn related manner. The hydra assay may be useful for establishing priorities to test agents in a more elaborate system, but substances less soluble than xylene may exceed the test's applicability. ... Pregnant CFY rats /were exposed/ by continuous inhalation to 1,000 mg/cu m (230 ppm) of a xylene mixture (10% o-, 50% m-, 20% p-xylene, and 20% ethylbenzene) on gestational days 9 through 14. At this concn, the xylene mixture produced skeletal effects including an increased incidence of supernumerary ribs (9/143 alizarin-stained fetuses in the dosed group compared to 2/143 in the control group). ... Two cases of agnathia (absence of mandible) /were reported/ in 286 pups. RATS PRETREATED WITH XYLENE OR PHENOBARBITAL & THEN EXPOSED TO N-HEXANE, SHOWED A MARKEDLY INCR PEAK SERUM CONCN OF THE NEUROTOXIC METABOLITE 2,5-HEXANEDIONE. Admin of xylenes to rats caused decr in liver glutathione (GSH) concn, reduction in glutathione concn was most pronounced after treatment with o-xylene isomer (4.0 mmol/kg). Hepatocytes isolated from male Sprague-Dawley rats (200-275 g) were exposed to halogenated and non-halogenated hydrocarbons. Leakage of cellular enzymes and inhibition of respiration were monitored as indicators of toxicity. Cell suspensions contained 2-3X10+6 cells/ml and were viable for 6 hr as indicated by a < 10% increment in the fractional release of aspartate aminotransferase activity. The hydrocarbons were added to the cell suspension as 20% solutions in ethanol. The addition of 20 mM dimethylbenzene (DMB) caused a rapid release, which peaked within 60 min, into the medium. Approximately 22% (n= 4) of the total aspartate aminotransferase was found in the medium and the release was concentration dependent. Cellular oxygen consumption was reduced when DNB was present, and the reduction was dose dependent. The relationship of the effects of cellular respiration to alteration in mitochondrial function was studied using dinitrophenol (DNP) and succinate, an NADH-independent mitochondrial substrate. DNP-induced oxygen stimulation was abolished by 10 mM DMB. Succinate-stimulated respiration was unaffected by 2.5 mM DMB, but DPN-stimulated respiration was significantly reduced. Mitochondrial function returned to normal within 1 hr. /Dimethylbenzene/ In some rats exposed to 3000 mg/cu m mixed xylenes for 8 hours per day on six days per week for 110-130 days, exposure resulted in paralysis of the hind legs, weight loss, a slight decrease in leukocytes, increases in blood urea, urinary blood and albumin, and hyperplasia of the bone marrow. Slight congestion of kidney, liver, heart, adrenal, lung and spleen were observed. Cellular desquamation of glomeruli and necrosis of the convoluted tubules were also reported. Ten to 20 applications of undiluted mixed xylenes on the ears or shaved abdomen of rabbits for two or four weeks resulted in moderate to marked erythema and oedema, with superficial necrosis at both sites. After introduction of two drops of mixed xylenes into the rabbit eye, slight conjunctival irritation and transient corneal injury were observed. Application of undiluted xylene to the eye caused corneal lesions in cats. ... Two drops of mixed xylenes instilled into rabbit eyes induced slight conjunctival irritation with very slight, transient corneal injury. Nine rats inhaled 690 ppm of mixed xylenes, 8 hours/day, 6 days/week for 110 to 130 days, while six rabbits inhaled 1200 ppm 8 hours/day, 6 days/week for 40 to 50 days. In some animals, exposure resulted in paralysis of hind legs; weight loss; a slight decrease in leukocytes; increases in blood urea, urinary blood, and albumin; and hyperplasia of the bone marrow. Slight congestion of the kidney, liver, heart, adrenal, lung, and spleen was observed. Fertility and pregnancy indices were no different among male and female rats inhaling 60, 250, or 500 ppm xylene, 6 hours/day for 131 premating days, during 20 mating days, and throughout gestation and lactation as compared with the concurrent control animals. Rats exposed to 300 ppm, 6 hours/day, 5 days/week for 18 weeks showed increased hepatic monooxygenation. /From table/ The effects of acute xylene exposure on the enkephalinergic neuromodulatory system were studied in rats. Male Sprague-Dawley rats were injected ip with 0 or 1.6 mL/kg xylene daily for 3 consecutive days. Three hr after the last dose, they were killed and the brains were removed. The brains were dissected into the parietal cortex. caudate putamen, medial preoptic areas of the hypothalamus, globus pallidus, olfactory tubercle, and central amygdaloid nuclei (CA). The various brain parts were analyzed for changes in their met-enkephalin content by an immunostaining technique. Xylene decr the extent of immunostaining for met-enkephalin in the globus pallidus, olfactory tubercle, and the CA. The decr in the globus pallidus and CA were statistically significant. The decr in the olfactory tubercle was not significant. Immunostaining for met-enkephalin in the other brain regions was not affected by xylene. The authors conclude that xylene decr the met-enkephalin content of specific brain regions. The regional specificity of these decr suggests that enkephalins are involved in xylene neurotoxicity. ... Mixed xylenes (60% m-, 14% p-, 9% o-xylene, and 17% ethylbenzene) in corn oil were administered by gavage to mice and rats 5 days/week for 103 weeks. Mice received daily doses of 500 or 1000 mg/kg; rats received 250 or 500 mg/kg. No gross or histopathological lesions were related to these treatments; tumor incidence was similar for treated and control groups of either species. There was no evidence for carcinogenicity. When tested for mutagenicity, o-, m-, and p-xylene were negative by assay in the Ames system using Salmonella typhimurium strains TA1535, TA1537, TA1538, TA98, and TA100 with or without metabolic activation by S9 fraction derived from livers of rats either untreated or induced with Aroclor 1254. Xylene did not change the number of sister chromatid exchanges or the number of chromosomal aberrations in human lymphocytes in vitro. /Xylenes/ Teratogenicity has been evaluated for a xylene mixture (9.1% o, 60.2% m, 13.6% p, and 17.0% ethylbenzene) in pregnant albino CD-I mice given the mixture at dosages of 2.4, 3.0, and 3.6 ml/kg/day by gavage on days 6-15 of gestation. At these near-lethal doses, xylene produced a significant increase in malformations, with cleft palate being the major malformation observed. Exposure of CFY rats to 1000 mg/cu m (230 ppm) xylene for 24 hr/day from day 9 to 14 of gestation was not teratogenic, although there was an increase in skeletal anomalies consisting of extra ribs and fused sternebrae. Rats exposed 6 hr/day for 3 days to 2000 ppm of a xylene mixture of the o, m, and p isomers showed an increase in hepatic cytochrome p450 and NADPH-cytochrome c reductase. The p isomer was less potent in inducing this effect that the other isomers or the mixture. Microsomes from lung and kidney also showed increases in cytochrome p450 for the xylene mixture and isomers except the p isomer failed to induce cytochrome p450 in microsomes from kidney. ... Under the conditions of these 2 yr gavage studies, there was no evidence of carcinogenicity of xylenes (mixed) for male or female F344/N rats given 250 or 500 mg/kg or for male or female B6C3F1 mice given 500 or 1,000 mg/kg.
National Toxicology Program Studies: Two yr toxicology and carcinogenesis studies were conducted by admin 0, 250, or 500 mg/kg xylenes in corn oil by gavage to groups of 50 F344/N rats of each sex, 5 days per week for 103 weeks. Groups of 50 B6C3F1 mice of each sex were administered 0, 500, or 1,000 mg/kg xylenes on the same schedule. ... Under the conditions of these 2 yr gavage studies, there was no evidence of carcinogenicity of xylenes (mixed) for male or female F344/N rats given 250 or 500 mg/kg or for male or female B6C3F1 mice given 500 or 1,000 mg/kg.
Non-Human Toxicity Values: LD50 Rat oral 4.3 g/kg LD50 Rat oral 10 mL/kg /Xylene/ LD50 Mouse oral 1590 mg/kg /Xylene/ LC50 Rat inhalation 6,350 ppm/4 hr LCLo Rat inhalation 8,000 ppm/4 hr LC50 Rat inhalation 6,350 ppm/4 hr LC50 Mouse inhalation 3,907 ppm/6 hr LD50 Rat oral 4.3 g/kg and 10 ml/kg /Xylene/ LD50 Mouse oral 1590 mg/kg /Xylene/ LC50 Rat oral 29,000 mg/cu m (6670 ppm) /Xylene/ LD50 Rat oral range from 3523 mg/kg to 8600 mg/kg. /Mixed Xylenes/ LD50 Mouse (B6C3F1) oral 5251 mg/kg (female) and 5627 mg/kg (male). /Mixed Xylenes/ LD50 Rabbit dermal > 5 ml/kg (43 g/kg). /Mixed Xylenes/
Ecotoxicity Values: LD50 Goldfish 13 mg/l/24 hr /Conditions of bioassay not specified, no specific isomer/ LC50 Rainbow trout 13.5 mg/l/96 hr /Conditions of bioassay not specified, no specific isomer/ LC50 Fathead minnow 46 mg/l/1 hr; 42 mg/l/24-96 hr @ 18-22 deg C, in a static bioassay /No specific isomer/ LC50 Carassius auratus (goldfish) 16.9 ppm/96 hr /Conditions of bioassay not specified, no specific isomer/
TSCA Test Submissions: Acute oral toxicity was evaluated in groups of 7 Sprague-Dawley male albino rats administered single doses of undiluted xylenes by oral gavage at levels of 0.85, 2.55, 4.25, 5.95, 7.65, and 8.65 g/kg of body weight. Mortality was observed in 3 animals in the 4.25 g/kg dose group, 5 in the 5.95 g/kg dose group, and in all animals in the two highest dose groups. The LD50 value was calculated to be 4.5 g/kg (3.3 - 6.2 g/kg confidence limits) by the Litchfield and Wilcoxon method. Clinical observations included shallow, rapid respiration and bloody discharge around the nose in the 4.25 and 5.95 g/kg dose group and marked depression to coma, shallow respiration, lacrimation, and bloody crusts around the eyes and nose in the 7.65 and 8.50 g/kg dose group. Gross necropsy revealed congested to hemorrhagic lungs, pale, mottled livers and kidneys, and excessive hyperhemia to a grey-green discoloration of the walls of the stomach and upper intestinal tract in decedents; survivors appeared normal. Xylene (CAS No. 1330-20-7) was tested for dermal irritation. The test substance was applied at 0.5 ml to intact and abraded skin of three groups of 6 rabbits (sex not reported). The first group had the sites occluded for 4 hours, the second for 24 hours, and the third were unoccluded. Well-defined to moderate erythema and edema were noted in the unoccluded and the 4-hour occluded groups. Well-defined to moderate erythema and well-defined to severe edema were observed in the 24-hour occluded group. The primary irritation scores were 4.2, 5.2, and 4.8 for 4-hour occluded, 24-hour occluded and non-occluded groups, respectively. Xylene (CAS No. 1330-20-7) was tested for eye irritation. The test substance was applied at 0.1 ml to the conjunctival sac of one eye of each of 6 rabbits (sex not reported) Mild iritis was observed in most eyes at 1 hour; slight corneal opacity was observed in 2 eyes at 24 hours, and 1 eye at 48 hours. Moderate conjunctival irritation was present in most eyes at 1 and 24 hours, but was slight at 48 and 72 hours. All eyes were normal by 7 days. Xylene (CAS# 1330-207) was evaluated for developmental effects in mice administered the test substance by gavage at dose levels of 0, 0.6, 1.2, 2.4, 3.0, 3.6 or 4.2 mL/kg/day. There were 15/15 mortalities at 4.2 mL/kg/day and 12/38 at 3.6 mL/kg/day. Maternal body weight gain was reduced in survivors at 3.6 mL/kg/day (p<0.05). The average maternal liver weight was increased at 2.4 and 3.0 mL/kg/day and the average fetal weight was reduced at 2.4 and 3.0 mL/kg/day (p<0.05). The average percent of malformed fetuses was increased at 2.4, 3.0, and 3.6 mL/kg/day (p<0.01). Cleft palate was observed in the 1.2, 2.4, 3.0, and 3.6 mL/kg/day groups. Mixed xylenes (CAS# 1320-20-7) were evaluated for developmental effects in groups of male and female Charles River rats administered the test substance for 6 hours/day by inhalation at concentrations of 0 (group I), 60 (group II), 250 (group III), 500 ppm (groups IV, V, and VI). Group I consisted of 30 untreated males and 30 untreated females, groups II and III consisted of 10 treated males and 10 treated females in each, group IV contained 20 treated males and 40 treated females, group V contained 10 treated males and 20 untreated females, and group VI contained 10 untreated males and 20 treated females. Treated animals were exposed for 131 days pre-mating and 20-day mating period. Females continued to be exposed during days 1-20 of gestation and on days 5-20 of lactation. Twenty group I (control) and 12 group IV females were sacrificed on day 21 of gestation in order to evaluate mating performance and pregnancy data. Group III and group VI showed mating indices which were significantly lower than controls. High dose females (groups IV and VI) showed an increased mean number of resorption sites. Mean fetal weight was lower in the high dose group than in the control group (this difference was only significant for female fetuses). Mixed xylenes (CAS# 1320-20-7) were evaluated for developmental effects in groups of male and female Charles River rats administered the test substance for 6 hours/day by inhalation at concentrations of 0 (group I), 60 (group II), 250 (group III), 500 ppm (groups IV, V, and VI). Group I consisted of 30 untreated males and 30 untreated females, groups II and III consisted of 10 treated males and 10 treated females in each, group IV contained 20 treated males and 40 treated females, group V contained 10 treated males and 20 untreated females, and group VI contained 10 untreated males and 20 treated females. Treated animals were exposed for 131 days pre-mating and 20-day mating period. Females continued to be exposed during days 1-20 of gestation and on days 5-20 of lactation. Twenty group I (control) and 12 group IV females were sacrificed on day 21 of gestation in order to evaluate mating performance and pregnancy data. Group III and group VI showed mating indices which were significantly lower than controls. High dose females (groups IV and VI) showed an increased mean number of resorption sites. Mean fetal weight was lower in the high dose group than in the control group (this difference was only significant for female fetuses). Xylene (CAS# 1330-20-7) was evaluated for acute dermal toxicity. The test substance was applied undiluted to the skin of New Zealand albino rabbits for 24-hours. Dosages and mortality data are as follows: 2000 (0/1 M); 3160 (0/1 F); 5010 (1/1 M in 2-days); 7940 mg/kg body weight (1/1 F in 2-days). Clinical signs included weight loss, increasing weakness, collapse, and death. Necropsy findings included hemorrhagic areas of the lungs, liver, and kidney discoloration, enlarged gall bladder, and gastrointestinal inflammation. The LD50 was determined to be greater than 3160 mg/kg b.w.
Metabolism/Pharmacokinetics:
Metabolism/Metabolites: IN HUMANS ... EXPOSED TO APPROX 0.2-0.4 MG/L XYLENE ISOMERS (O-, M-, P-XYLENE) OR 1:1:1 MIXT FOR UP TO 8 HR ... MORE THAN 95% ... EXCRETED BY HUMANS INTO URINE IN FORM OF METHYLHIPPURIC ACIDS. ... SMALL PORTION ... EXCRETED INTO URINE AS CORRESPONDING XYLENOLS. Quantitative determination of urinary metabolites in humans exposed to xylene using colorimetric determination is widely used. The metabolites of ... xylene are measured as ... methyl hippuric acid (MHA), paper chromatography and thin layer chromatography are necessary as pretreatments of samples. The addition of pyridine, p-dimethylaminobenzaldehyde (DAB) and acetic anhydride to glycine conjugates gives the most stable color development. Excellect analytical sensitivity and specificity with gas chromatographic methods requires pretreatment with diazomethane for methylesterification of methyl hippuric acid. ... Xylene is metabolized to a toxic aldehyde, methylbenzaldehyde ... . The principal difference between human and animal xylene metabolism is the production of p-methylbenzaldehyde catalyzed by rabbit and rodent lung and liver alcohol dehydrogenase. Glucuronidation apparently occurs after saturation of normal glycine metabolic pathways that predominate in humans as evidenced by the methylhippuric acids in urine. Methylbenzyl alcohol and dimethylpheonl have not been reported in human studies. Generally, the xylenes are metabolized to the corresponding o-, m-, or p-toluic acids, and excreted in urine free or conjugated with glycine as methylhippuric acid.
Absorption, Distribution & Excretion: For exposure to xylene at concn averaging 100 ppm, the mean methyl hippuric acid concn should average 1.5 to 2 g/g creatinine (range 1.0-3.0) in a sample collected during the second part of the exposure period. Almost total urinary excretion of xylene occurs by 24 hours. The rapid xylene clearance from blood (plasma half-life of 4 hours) prevents adequate biological monitoring of serum samples. ... XYLENES HAVE BEEN REPORTED TO CROSS THE HUMAN PLACENTA. XYLENE, WHEN INGESTED, IS READILY ABSORBED BY THE HUMAN SYSTEM, AS HAS BEEN SHOWN IN ACCIDENTAL INGESTIONS. ABSORPTION THROUGH INTACT & BROKEN SKIN OCCURS READILY. ... XYLENE IS ABSORBED MAINLY THROUGH MUCOUS MEMBRANES & PULMONARY SYSTEM. ... ABSORBED XYLENE IS TRANSLOCATED THROUGH THE VASCULAR SYSTEM. ... The uptake of solvent by man during whole body exposure to toluene and xylene occurs almost exclusively through the lung; dermal uptake represents about 1% of the total uptake. Male rats were injected ip with benzene, toluene, or a mixt or xylene isomers at 20 mmol hydrocarbon/kg daily for 3 days. The effects of administration of these hydrocarbons upon their own in vitro metabolism, as well as upon cytochrome p450, NADPH-cytochrome c reductase, aminopyrine N-demethylase, aniline hydroxylase, glutathione, glutathione S-transferase, and UDP-glucuronyltransferase in liver were studied. The correlation between xylene exposure and urinary excretion of methyl hippuric acid (MHA) was studied in 40 workers (35 men, 5 women) employed in the paint industry. Subjects were exposed primarily to xylene although exposure to 11 other solvents was possible. Personal sampling showed 8 hr time weighted average for xylene ranged from 0-865 mg/cu m with a median exposure of 69 mg/cu m. Urine was collected over one 24 hr period for each worker. Personal air samples were collected for each worker over the course of a complete workday. Methyl hippuric acid excretion was linearly correlated to the 8 hr time weighted average for xylene exposure after adjustment for body weight. The total amount of methyl hippuric acid excreted in the urine over 24 hr showed virtually the same correlation to xylene exposure (r= 0.84) as the methyl hippuric acid excretion during the latter part of the workshift (r= 0.81, sampling time 4-5 hr) among 37 workers exposed to 8 hr time weighted average xylene concentrations of 0-200 mg/cu m. Humans exposed to 46 or 92 ppm of o-, m-, p-xylene or a mixture (1:1:1) of the three for 8 hr absorbed approx 64% of the inhaled xylene. No difference in the absorption rate was reported due to level of exposure, length of exposure, or the type and/or mixture of the xylene isomers. The absorption of xylene appeared to vary among individuals due to differences in ventilation rate. ... Individuals with an incr ventilation rate retained less xylene. Male Wister rats exposed to xylene in air (80% m-xylene, 12% p-xylene) for 6 hr/day, 5 days/week for 2 weeks accumulated 64.8 mg/xylene/g of perirenal fat after five exposures and 127.0 mg/xylene/g of perirenal fat after 10 exposures to xylene. Groups of five male Wister rats were exposed to 300 ppm of technical grade xylene (85% m-xylene, 15% other isomers) for 6 hr/day, 5 days a week for 5, 9, 14, or 18 weeks. Analysis of the perirenal fat by gas chromatography indicated that 67.6, 57.4, 40.7, and 36.6 mg/g of tissue was present after 5, 9, 14, or 18 weeks of exposure, respectively. The gradual decr in the xylene content of perirenal fat as the length of exposure was incr may have been the result of an incr metabolic rate. Groups of six male human volunteers were exposed to 200 or 100 ppm of a xylene mixture (49.4% ethylbenzene) for 30 min through a breathing valve. The first group, while being exposed to 200 ppm of the xylene mixture, exercised on a bicycle ergometer for 90 min. The second group, exposed to 100 ppm, ... incr their level of exercise at 30 min intervals. At rest and during light work, pulmonary uptake ... was about 63% during the 2 hr exposure period. At a more strenuous work level, pulmonary uptake ... was only 51% after a correction had been applied for the incr breathing vol that occurs during heavy exercise. 15 human male volunteers exposed for 70 min periods to 100 and 300 ppm at rest and 300 ppm while exercising absorbed a mean of 180, 541, or 1210 mg of xylene, respectively. The xylene absorption rate for both exposure levels was 43% while resting and 64% while exercising, assuming inhalation volumes of 20 cu m/24 hr at rest and 10 cu m/8 hr at work. Xylene possesses marked solubility in adipose tissue (distribution coefficient fat/blood approximately 100). ... Xylene vapor is absorbed rapidly from the lungs, and xylene liquid and vapor are absorbed slowly through the skin. Of the xylene absorbed, about 95% is metabolized in the liver to methylhippuric acid and 70 to 80% of metabolites are excreted in the urine within 24 hr. However, the many variables which affect the absorption, metabolism and clearance of xylene incl exercise, alcohol intake, cigarette smoking, co-exposure to other solvents, gender, and GI, hepatic and renal pathology. FOLLOWING EXPOSURE OF RABBITS TO ATMOSPHERE OF ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM) OR IN OTHER ORGANS. /XYLENES/ IN HUMANS ... EXPOSED TO APPROX 0.2-0.4 MG/L XYLENE ISOMERS (O-, M-, P-XYLENE) OR 1:1:1 MIXT FOR UP TO 8 HR ... PULMONARY RETENTION WAS 64%, WHICH WAS ... INDEPENDENT OF DOSAGE OR DURATION OF EXPOSURE. AFTER EXPOSURE, ONLY 5% OF RETAINED XYLENES WERE ELIM IN EXPIRED AIR. MORE THAN 95% ... EXCRETED BY HUMANS INTO URINE IN FORM OF METHYLHIPPURIC ACIDS. ... SMALL PORTION ... EXCRETED INTO URINE AS CORRESPONDING XYLENOLS.
Interactions: Concomitant ingestion of ethyl alcohol potentiated the deleterious behavioral effects of xylene in animals. Alcohol also potentiated the weak hepatic microsomal enzyme-inducing effects of xylene, and the combination produced liver damage at doses of xylene which were not effective alone. Daily oral administration of 55 mg balagrin in xylene (20% balagrin-80% xylene) for 4 months, or administration of 235 mg xylene/kg stimulated rat serum ornithine carbamoyl transferase and leucine aminopeptidase, and decreased the relative weight of the liver. Only balagrin plus xylene decreased serum alpha-2 globulins, stimulated serum and liver cholinesterase, and decreased liver triglycerides, whereas xylene alone increased the blood leukocyte count and stimulated liver cytochrome oxidase, and inhibited it in the testes and brain. Xylene alone stimulated liver isocitrate dehydrogenase and glucose dehydrogenase more than did balagrin plus xylene. ... A 79% incr in hepatic DNA indicated repair. ... When consumed prior to exposure, ethanol decreases the metabolic clearance of xylene by approximately one-half. The present study involved an investigation of possible interactions between 3 aromatic hydrocarbons in their ability to affect the development of the rat embryonic brain in vitro during 40 hr of the organogenic period. The embryos were explanted on day 10.5 of gestation and cultured in heat-inactivated rat serum to which various combinations of toluene, xylene or benzene had been added in 0.1% DMSO as dispersant. The actual amt of solvent present at different times in the culture period was quantitated using GC. The results showed that the solvents affected embryonic development in an additive manner (toluene 0.287 + or - 0.077; xylene 0.331 + or - 0.026; benzene 0.256 + or - 0.020; toluene + xylene 0.294 + or - 0.047; toluene + benzene 0.261 + or - 0.025; xylene + benzene 0.252 + or - 0.014 mL/mL). In each case the embryos had a small flattened head. Also, addition of below-threshold levels of solvents alone or in combo resulted in apparently normal embryonic development. The data indicate that exposure to combinations of toluene, xylene and benzene result in an additive rather than a synergistic or potentiating effect on rat embryonic development in vitro. The health effects of exposure to a mixture of toluene and xylene isomers were studied on the fourth or fifth days of a working week in factories in China. The study population consisted of 233 exposed subjects and 241 controls. The prevalence of some subjective symptoms significantly incr in the exposed population, and the symptom profiles were similar to those found after exposure to toluene or xylenes alone. Hematology and serum biochemistry did not show notable changes. It seems reasonable to conclude that the effects of the toxicities of toluene and xylenes in combo are additive. Aromatic compounds are metabolized via the p450 mixed function microsomal enzyme system in the endoplastic reticulum of the liver. The co-ingestion of ethanol has an effect on the metabolism of xylene. Ethanol inhibits the oxidation of the aromatic ring and also alkyl side chain oxidation. This is probably through a direct inhibitory effect on the microsomal oxidation by ethanol. Xylene blood concentrations increase up to two-fold following ethanol ingestion indicating inhibition of metabolism.
Pharmacology:
Interactions: Concomitant ingestion of ethyl alcohol potentiated the deleterious behavioral effects of xylene in animals. Alcohol also potentiated the weak hepatic microsomal enzyme-inducing effects of xylene, and the combination produced liver damage at doses of xylene which were not effective alone. Daily oral administration of 55 mg balagrin in xylene (20% balagrin-80% xylene) for 4 months, or administration of 235 mg xylene/kg stimulated rat serum ornithine carbamoyl transferase and leucine aminopeptidase, and decreased the relative weight of the liver. Only balagrin plus xylene decreased serum alpha-2 globulins, stimulated serum and liver cholinesterase, and decreased liver triglycerides, whereas xylene alone increased the blood leukocyte count and stimulated liver cytochrome oxidase, and inhibited it in the testes and brain. Xylene alone stimulated liver isocitrate dehydrogenase and glucose dehydrogenase more than did balagrin plus xylene. ... A 79% incr in hepatic DNA indicated repair. ... When consumed prior to exposure, ethanol decreases the metabolic clearance of xylene by approximately one-half. The present study involved an investigation of possible interactions between 3 aromatic hydrocarbons in their ability to affect the development of the rat embryonic brain in vitro during 40 hr of the organogenic period. The embryos were explanted on day 10.5 of gestation and cultured in heat-inactivated rat serum to which various combinations of toluene, xylene or benzene had been added in 0.1% DMSO as dispersant. The actual amt of solvent present at different times in the culture period was quantitated using GC. The results showed that the solvents affected embryonic development in an additive manner (toluene 0.287 + or - 0.077; xylene 0.331 + or - 0.026; benzene 0.256 + or - 0.020; toluene + xylene 0.294 + or - 0.047; toluene + benzene 0.261 + or - 0.025; xylene + benzene 0.252 + or - 0.014 mL/mL). In each case the embryos had a small flattened head. Also, addition of below-threshold levels of solvents alone or in combo resulted in apparently normal embryonic development. The data indicate that exposure to combinations of toluene, xylene and benzene result in an additive rather than a synergistic or potentiating effect on rat embryonic development in vitro. The health effects of exposure to a mixture of toluene and xylene isomers were studied on the fourth or fifth days of a working week in factories in China. The study population consisted of 233 exposed subjects and 241 controls. The prevalence of some subjective symptoms significantly incr in the exposed population, and the symptom profiles were similar to those found after exposure to toluene or xylenes alone. Hematology and serum biochemistry did not show notable changes. It seems reasonable to conclude that the effects of the toxicities of toluene and xylenes in combo are additive. Aromatic compounds are metabolized via the p450 mixed function microsomal enzyme system in the endoplastic reticulum of the liver. The co-ingestion of ethanol has an effect on the metabolism of xylene. Ethanol inhibits the oxidation of the aromatic ring and also alkyl side chain oxidation. This is probably through a direct inhibitory effect on the microsomal oxidation by ethanol. Xylene blood concentrations increase up to two-fold following ethanol ingestion indicating inhibition of metabolism.
Environmental Fate & Exposure:
Environmental Fate/Exposure Summary: Commercial xylene is a mixture of the three xylene isomers in the following percent ranges: 2-xylene, 10-25 percent; 3-xylene 45-70 percent; and 4-xylene 6-15 percent. Its production and use in petroleum products, as a chemical solvent, and as an organic synthesis reagent may result in its release to the environment through various waste streams, including discharges from storage facilities and the use of automobiles. Natural sources of xylene such as petroleum, forest fires and the volatiles of plants may also account for this compounds presence in the environment. Xylene will enter the atmosphere primarily from fuel emissions and exhausts linked with its use in gasoline. Based upon an experimental vapor pressure of 7.99 mm Hg at 25 deg C, xylene is expected to exist entirely in the vapor phase in the ambient atmosphere. Vapor-phase xylene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals with an estimated atmospheric lifetime of about 1-2 days. Xylene is expected to have moderate to high mobility in soils based upon experimental Koc values obtained with a variety of soils at differing pH values and organic carbon content. Volatilization from moist soil surfaces is expected based on an experimental Henry's Law constant of 7.0X10-3 atm-cu m/mole. Biodegradation is an important environmental fate process for xylene. In general, it has been found that xylene is biodegraded in soil and groundwater samples under aerobic conditions and may be degraded under anaerobic denitrifying conditions. In water, xylene is expected to adsorb somewhat to sediment or particulate matter based on its measured Koc values. This compound is expected to volatilize from water surfaces given its experimental Henry's Law constant. Estimated half-lives for a model river and model lake are 3 and 99 hours, respectively. The potential for bioconcentration in aquatic organisms is low based on an experimental BCF value of 20, measured in eels. Exposure to xylene may occur occupationally during its production or subsequent use, particularly as a solvent or in gasoline, via dermal and respiratory routes. The main route of exposure for the general population will be through inhalation of contaminated air as well as ingestion of contaminated drinking water and food. Dermal contact with household products containing xylene is also expected to be significant. (SRC)
Probable Routes of Human Exposure: Xylene can affect the body if it is inhaled, if it comes in contact with the eyes or skin, or if it is swallowed. THE ADVANTAGES & DISADVANTAGES OF USING SOFT CONTACT LENSES (IN HUMANS) IN ENVIRONMENTS WITH FUMES FROM SOLVENTS OR SPLASHES OF STRONG ACIDS & ALKALIS WERE STUDIED EXPERIMENTALLY. UPTAKE OF XYLENE BY LENS MATERIALS WAS UP TO 90 TIMES THAT BY PHYSIOLOGIC SALINE, USED TO SIMULATE TEAR FLUID. WHEN EXPOSED LENSES WERE SOAKED FOR 10 & 60 MIN IN A VERY SMALL VOLUME OF SALINE THE CONCN OF SOLVENT IN THAT SALINE WAS ONLY UP TO 23 & 11%, RESPECTIVELY, OF THAT IN DIRECT EXPOSED SALINE. SOLVENTS WERE RELEASED MAINLY TO THE AIR. CONTACT LENSES WOULD LEAD TO A PROLONGED EXPOSURE BUT TO A RATHER LOW CONCN AS COMPARED TO DIRECT EXPOSURE. Exposure to organic solvent vapors was investigated in 40 unit workplaces (with 189 workers) in 16 small scale industries in north-east Japan ... in which synthetic urushi lacquer was applied to produce non-metal tableware. ... Two furniture factories were also studied. The equipment used was carbon felt dosimeters and portable PID-GC ... . ... The gas chromatography could analyze benzene-toluene xylenes within 150 seconds. ... Toluene was the major pollutant in the workplace air, with small quantities of xylenes. ... Exposure did not exceed the current occupational exposure limit in all the cases except for the two workers, who were excessively exposed due to the generation of dense vapors in automated spraying process. ... There is a broad potential for exposure both to industrial workers in the production and use of the xylenes and to the general public (via vehicle exhausts, consumer products, etc). ... Number of USA workers exposed 140,000 /Time frame not mentioned/ NIOSH (NOES Survey 1981-1983) has statistically estimated that 1,528,018 workers (316,320 of these are female) are potentially exposed to xylenes in the US(1). An average xylene concn of 0.1 ppm was detected in the breathing zones of paint shops sampled in the US(2). Lab personnel are exposed to an average xylene concn of 0.16 ppm and material handling personnel are exposed to an average xylene concn of 1.6 ppm at hazardous waste facilities in the US(3). The 8 hour TWA exposure to xylenes for personnel at organic solvent recycling plants was measured as 1 ppm(4). A study from 1979-1987 calculated the average exposure to xylenes in paint manufacturing plants as 2.01 ppm in breathing zone locations(5). A survey of 97 autobody shops in the US reported the 8 hour TWA exposure to xylenes was 3.3 ppm for painters and 0.7 ppm for non-painting personnel(6). The 8 hour TWA for worker exposure to xylenes in a German histology laboratory and a US histology laboratory was measured as 243-295 mg/cu m and 11-315 mg/cu m respectively(7). The 8 hour TWA for worker exposure to xylenes in a US hospital laboratory was measured as 3-1700 mg/cu m(7). Occupational exposure may be through inhalation and dermal contact with this compound at workplaces where xylenes are produced or used(SRC). The general population will be exposed to xylenes largely via inhalation of ambient air, particularly in areas with heavy traffic, near filling stations and near industrial sources such as refineries(SRC). Exposure may also arise from consuming contaminated food and drinking water(SRC). An average concn of 0.37 ppb of 3- and 4-xylene was measured in blood samples collected from 60 persons in the US that are not occupationally exposed to xylenes(8). Humans are exposed to xylene primarily from air, particularly in areas with heavy traffic, near filling stations, near industrial sources such as refineries or where xylene is used as a solvent. Exposure may also arise from drinking contaminated well water near leaking underground gasoline storage tanks or from spills of petroleum products. (SRC) Benzene and xylenes are components of gasoline. The US population exposed to xylenes from petroleum related sources can be assumed to be the same as for benzene, namely: people choosing self-service at gasoline service stations 37,000,000; people living in the vicinity of gasoline service stations 118,000,000; petroleum refineries 6,597,000; urban exposure (auto emissions) 113,690,000(1). /Xylenes/
Body Burden: ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE WAS ONE OF THE AROMATICS IDENTIFIED. FOLLOWING EXPOSURE OF RABBITS TO AN ATMOSPHERE OF ABOUT 3,000 MG/CU M FOR 8 HR/DAY, 6 DAYS/WK, FOR 130 DAYS, XYLENE WAS FOUND AT SLIGHTLY HIGHER AVG CONCENTRATIONS IN THE ADRENAL (148 PPM), BONE MARROW (130 PPM), SPLEEN (115 PPM), & BRAIN (100 PPM) THAN IN BLOOD (91 PPM) OR IN OTHER ORGANS.
Average Daily Intake: AIR INTAKE: (Assume typical concn 4.0 ppb) 353 ug; WATER INTAKE: (Assume typical concn 0-1 ppb) 2 ug; FOOD INTAKE: Insufficient data. (SRC)
Natural Pollution Sources: Common naturally occurring sources of xylenes are petroleum(1); forest fires and volatiles of plants(2).
Artificial Pollution Sources: Agricultural spraying. Xylene's production and use in petroleum products, as a chemical solvent and intermediate, and for the manufacture of terephthalic acid and herbicides(1-4) may result in its release to the environment through various wastestreams(SRC).
Environmental Fate: Several experimental Koc values for xylene have been reported in soil samples with differing pH and organic carbon content values(1-3). The reported Koc value of o-xylene is in the range of 48-68(1). Mixtures of xylenes in silt clay soil at pH 8.5 and organic carbon content of 0.17 percent have a reported experimental Koc of 365; xylene in silt clay soil at pH 7.0 and organic carbon content of 1.40 percent have a reported experimental Koc of 39; xylene in coarse sand at pH 6.8 and organic carbon content of 0.09 percent has a reported experimental Koc of 311; xylene in coarse sand at pH 6.6 and organic carbon content of 0.04 percent has a reported experimental Koc of 2600(2). Xylene in Norwegian forest soil at pH 5.6 and organic carbon content of 0.2 percent has a reported experimental Koc of 129; xylene in Norwegian agricultural soil at pH 7.4 and organic carbon content of 2.2 percent has a reported experimental Koc of 158; xylene in Norwegian forest soil at pH 4.2 and organic carbon content of 3.7 percent has a reported experimental Koc of 289(3). Xylene isomers have been observed to pass through soil at a dune-infiltration site on the Rhine River(4) and to leach into groundwater under a rapid infiltration site(5). Based on an experimental vapor pressure of 7.99(6), volatilization from dry soil surfaces is expected(SRC). Volatilization from moist soil surfaces is expected based on an experimental Henry's Law constant of 7.0X10-3 atm-cu m/mole(7) reported for a mixture of xylenes. Xylene is degraded in standard biodegradability tests using various inocula including sewage, activated sludge and seawater(8-13). AQUATIC FATE: Based on a recommended classification scheme(1) and experimentally determined Koc values in the range of 39-359(2-4), xylene is expected to adsorb somewhat to suspended solids and sediment in water(SRC). Xylene is expected to volatilize from water surfaces(1,SRC) based on an experimental Henry's Law constant of 7.0X10-3 atm-cu m/mole(5) reported for a mixture of xylene isomers. Estimated half-lives for a model river and model lake are 3 and 99 hours, respectively(1,SRC). Xylene is degraded in standard biodegradability and field tests using various inocula including sewage, activated sludge and seawater(6-12). ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), xylene, which has an experimental vapor pressure of 7.99 mm Hg at 25 deg C(2), will exist solely as a vapor in the ambient atmosphere. Vapor-phase xylene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the atmospheric lifetime of xylene is about 1-2 days(3,4). Ambient levels of xylene are detected in the atmosphere due to large emissions of this compound(SRC).
Environmental Biodegradation: Xylenes are degraded in standard biodegradability tests using various inocula including sewage, activated sludge and seawater(1-7). Using a standard BOD dilution technique and a sewage inoculum, a theoretical BOD of 52, 80 and 44% was observed over a 5 day incubation period for 2-, 3-, and 4-xylene respectively(1). Using a standard BOD dilution technique and a benzene acclimated sludge inoculum, a theoretical BOD of 40, 10 and 26% was observed over an 8 day incubation period for 2-, 3-, and 4-xylene respectively(2). An unspecified amount of xylene was aerobically degraded in 8 days when contaminated groundwater was percolated through a microbial enriched soil column; the acclimation period was 3-4 days(2). A microbial consortium enriched from subsurface sediments contaminated with chlorinated hydrocarbons completely degraded 26 ug/l of xylene during a 21 day incubation period(3). 2-, 3-, and 4-Xylene at concns between 85 ug/l - 361 ug/l were degraded by a sand aquifer(4). Using a standard BOD dilution technique and an activated sewage inoculum, a theoretical BOD of 72 percent was observed over a 20 day incubation period for a mixture of xylene isomers(5). The biodegradation rate constant for xylene in an activated sludge inoculum was calculated as 0.2 hours-1, with a half-life of 3.3 hours(6). An activated sludge inoculum obtained from a Wisconsin wastewater treatment facility biodegraded a 5.53 ug/l sample of combined 3- and 4-xylene(7).
Environmental Abiotic Degradation: Xylenes degrade in the atmosphere primarily by reacting with photochemically produced hydroxyl radicals(SRC), with an atmospheric lifetime of about 1-2 days(1,2). The rate constant for the vapor-phase reaction of 2-, 3- and 4-xylene with photochemically-produced hydroxyl radicals has been measured as 13.7X10-12 cu cm/molecule-sec, 23.6X10-12 cu cm/molecule-sec and 14.3X10-12 cu cm/molecule-sec respectively at 25 deg C(3,4). This corresponds to an atmospheric half-life of about 28, 16 and 27 hours for 2-, 3 and 4-xylene respectively at an atmospheric concn of 5X10+5 hydroxyl radicals per cu cm(3,4). The rate constant for the vapor-phase reaction of 2-, 3- and 4-xylene with photochemically-produced nitrate radicals has been measured as 2.0X10-16 cu cm/molecule-sec(1), 7.6X10-17 cu cm/molecule-sec(2) and 1.4X10-16 cu cm/molecule-sec(2) respectively at 25 deg C. This corresponds to an atmospheric half-life of about 80, 220 and 115 days for 2-, 3 and 4-xylene respectively at an atmospheric concn of 5X10+8 nitrate radicals per cu cm(3,SRC). The rate constant for the vapor-phase reaction of a mixture of xylenes with ozone has been measured as approximately 5.0X10-21 cu cm/molecule-sec at 25 deg C(4). This corresponds to an atmospheric half-life of about 6 years at an atmospheric concn of 7.0X10+11 ozone molecules per cu cm(4,SRC). The photolysis of jet fuel JP-4 in water resulted in the degradation of 3- and 4-xylene, combined, from 1.46 to 1.38 to 1.34 to 1.20 mg/l in 0, 7, 14, and 21 days, respectively, in pond water(5). Xylene is not expected to undergo hydrolysis in the environment due to the lack of functional groups to hydrolyze(SRC). Ambient levels of xylene are detected in the atmosphere due to large emissions of this compound(SRC).
Environmental Bioconcentration: An experimental BCF value of 20 was measured for xylene isomers in eels exposed to petroleum for 10 days(1). According to a classification scheme(2), this BCF value suggests that bioconcentration in aquatic organisms is low(SRC).
Soil Adsorption/Mobility: Several experimental Koc values for xylenes have been reported depending upon the pH and organic carbon content of the soil(1-3). Batch experiments conducted with five low organic carbon content (0.04-1.12%), field contaminated soils (3 silty clay and two sandy loams) yielded Koc values ranging from 39-365(1). Xylene in Norwegian forest soil at pH 5.6 and organic carbon content of 0.2 percent has a reported experimental Koc of 129; xylene in Norwegian agricultural soil at pH 7.4 and organic carbon content of 2.2 percent has a reported experimental Koc of 158; xylene in Norwegian forest soil at pH 4.2 and organic carbon content of 3.7 percent has a reported experimental Koc of 289(2). Based on a recommended classification scheme(5) and the experimentally determined Koc values, xylene is expected to have moderate to high mobility in soils(SRC). Xylene isomers have been observed to pass through soil at a dune-infiltration site on the Rhine River(3) and to leach into groundwater under a rapid infiltration site(6).
Volatilization from Water/Soil: The Henry's Law constant for xylene has been reported as 7.0X10-3 atm-cu m/mole(1). This value indicates that xylene will volatilize rapidly from water surfaces(2,SRC). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec) is estimated as approximately 3 hours(2,SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec) is estimated as approximately 99 hours(2,SRC). An experiment which measured the rate of evaporation of xylenes from a 1:1000 jet fuel:water mixture found that this rate averaged approximately 0.6 times the oxygen reaeration rate(3). Combining this ratio with oxygen reaeration rates for typical bodies of water(2), one estimates that the half-life for evaporation of xylene from a typical river or pond is 29 and 144 hours, respectively(SRC).
Environmental Water Concentrations: DRINKING WATER: According to a federal survey of drinking water from groundwater supplies, xylenes are present in < 5% of supplies(1). In a survey of 30 Canadian water treatment facilities, xylene was detected in the drinking water in Canada with mean values of 1 ppb(2). Xylene has been qualitatively detected in the municipal drinking water supplies of Washington, DC(3), Philadelphia, PA(4), Cleveland, OH(5), Tuscaloosa, AL(6), Houston, TX(7), and New Orleans, LA(8). Xylene was detected at 0.1-2.9 ppb in drinking water wells in the vicinity of a landfill(7). A max of 0.1 ppb has been found in bank-filtered Rhine river water in the Netherlands(9). Xylene was detected, not quantified, in 14 drinking water supplies in Great Britain(10). Xylene was detected in the Woburn drinking wells in Woburn, MA(11). Xylene was detected in the drinking water produced by offshore installations in Norway at concns between 41-15,000 ng/l(12). GROUNDWATER: Xylene isomers have been found in groundwater under landfills(1) and in the hundreds ppb range under a coal gasification site, 15 months after gasification was completed(2). Xylene was detected in the groundwater near the Lipari landfill site in Mantau, NJ(3). Xylene was detected at concns of 2-9900 ppb, in the groundwater near an elementary school located in the US(4). Xylene was detected in the groundwater near an oil storage facility in Virginia at an average concn of 2.8 ppm(5). Xylene was detected in groundwater under a landfill in Norman, OK(6) and under a rapid infiltration site in Phoenix, AZ(7) at various concns. Xylene isomers were detected, not quantified, in 10 groundwater water supplies in Great Britain(8). SURFACE WATER: Xylene was detected, not quantified in the Mississippi River near New Orleans(1), the Black Warrior River in Tuscaloosa, AL(2), and the Glatt River in Switzerland(3). Xylene was detected, not quantified in Lakes Erie and Michigan(4). Xylene was detected at average concns of < 1 ppb in the raw water sources of 30 Canadian cities(5). Xylene was detected in only 1 of 204 surface water samples in the USA(6). Xylene was detected, not quantified in northern Lake Ontario(7). Xylene was detected in the surface waters of the Florida Bay at concns of 2-8 ug/l(8). Xylene was detected, not quantified, in 4 surface water supplies in Great Britain(9). SEAWATER: Xylene was detected, not quantified in Vineland Sound, MA(1) and the Gulf of Mexico(2). Xylene was detected in Valdez Harbor-Trans Alaskan Pipeline Terminal at concns of 0.2 and 0.7 ppb in 2 of 7 sampling sites(3). Unspecified concns of xylene were detected in the coastal waters of France(4). RAIN/SNOW: Xylene isomers were detected in the rainfall around West Los Angeles, at concns in the parts per trillion range(1). Xylene was identified in surface Antarctic snow from 1987-1991 at concns ranging from 12 to 198 ng/l and in deep snow samples at concns ranging from 8 to 29 ng/l(2). Xylene isomers were quantified during seven rain events in Portland, OR in 1984, and concns ranged from 34 to 260 ng/l(3).
Effluent Concentrations: Xylenes were detected at a low-level radioactive waste disposal site in Maxey Flats at concns of 0.12 and 0.48 ppm in 2 of 3 trench leachates(1). Xylene was detected in the effluent of an industrial plant near Philadelphia at a concn of 1,000 ppb(2). Xylene was detected in the effluent from containing ponds in Atigun river, Alaska at concns of 1.2 ppb(3). Xylene was detected in the treated effluents from offshore oil drilling platforms in the Gulf of Mexico at an average concn of 0.3 ppb(3). Xylene was detected at concns of 50 ppb and 2,250 ppb in the leachate of a steel production plant in Sydney, Nova Scotia(4). Xylene was detected in the leachate from selected Wisconsin landfills at concns between 1 ug/l and 100 ug/l(5). Xylene concns of 14,900 ppb, 2,651 ppb and 10,900 ppb were detected in gas samples at three landfill sites in Quebec, Canada(6). The total amount of xylene emissions from four wastewater treatment facilities in Los Angeles, CA were measured between 72-3683 kg/year(7). The concn of xylene emitted from a German incineration facility was 7.7 ug/cu-m(8). Emissions of combined 3- and 4-xylene and 2-xylene from an outboard boat motor into a freshwater lake in Germany were measured as 71 mg and 37 mg respectively, for 10 minutes of operation(9). Combined 3- and 4-xylene and 2-xylene were detected at concn ranges of 61.5-427.4 mg/km and 22.6-172.9 mg/km respectively, in the emissions of automobiles under various driving conditions in the UK(10). Xylene isomers were detected at mean concns of 1.13-2.27 ppm in the tailpipe emissions from automobiles in the UK(11).
Sediment/Soil Concentrations: Xylene was detected in the soil at the Clothier waste disposal facility in Granby, NY at an average concn of 79 ppb(1). Xylene was detected in the soil at a building construction site in the Netherlands at a maximum concn of 2,030 mg/kg(2). Xylene was detected at concns of about 1,500 ug/kg in the soil at a hazardous waste facility in Pemberton, New Jersey(3). Sediment collected from the River Morava, Slovakia, contained xylene at concns from 0.21 to 1.53 ug/kg wet weight(1). Sediment samples from the River Tees estuary, England, contained xylene at concns from 3.4 to 250 ppb(2).
Atmospheric Concentrations: SOURCE DOMINATED AREAS: Xylene was detected at concns between 0.2-99.0 ppb near two landfills in New Jersey(1), and at concns between 3-5 ppb downwind from an automobile painting plant in Janesville, WI(2). URBAN/SUBURBAN: Atmospheric concns of total mixed xylenes have been determined at various locations throughout the world. From approximately 1900 samples across the USA an average atmospheric concn of 4.0 ppb was observed(1). Atmospheric concns of xylene for several cities were reported; Turin, Italy 15.06 ppb; Los Angeles, CA 1-18.1 ppb; Sidney, Australia 3.9 ppb; Lincoln Tunnel, NY 33 ppb; Houston, TX 38 ppb; Philadelphia, PA 16 ppb; London, UK 2.3 ppb; Phoenix, AZ 8.6 ppb(2). Combined 3- and 4-xylene was detected at an average concn of 18.1 ppb and 2-xylene was detected at an average concn of 7.2 ppb in 39 US cities(3). 2-, 3- and 4-Xylene were detected in the Lincoln Tunnel, NY at concns of 114 ppb, 49 ppb and 74 ppb respectively(4). Ambient concns of xylene isomers were reported for several urban cities; Zurich, Switzerland 9-21 ppb(5); Berlin, Germany 13.6-18.1 ppb(5); Paris, France 0.6-1.5 ppb(5); Johannesburg, Pretoria and Durban South Africa 1.3-4.5 ppb(5); London, England 0.8-2.8 ppb(5); Tokyo, Japan 0.4-1.0 ppb (5); Phoenix, AZ 1.8-4.2 ppb(5); Houston, TX 1.3-3.8 ppb(5); St. Louis, MO 0.3-1.0 ppb(5); Denver, CO 0.6-2.9 ppb(5) and Staten Island, NY 2.6 ppb(5). RURAL/REMOTE: The median concn of xylene sampled at 114 areas in the USA was 0.18 ppb with a maximum concn of 78 ppb(1). Ambient concns of xylene isomers were reported for several rural locations; Loop Head, Ireland 0.95-2.7 parts per trillion(2); rural Brazil 80-140 parts per trillion(2); rural Kenya 10-330 parts per trillion(2) and Niwot Ridge, CO 2-55 parts per trillion(2).
Food Survey Values: Unspecified concns of xylenes were detected in cheese products obtained from dairy cattle in the French Alps(1). Unspecified concns of xylenes were detected in mother's milk in Bayonne, NJ; Jersey City, NJ; Baton Rouge, LA; Pittsburgh, PA; Charleston, WV(2). Unspecified amounts of xylenes were identified in human milk by gas chromatography/mass spectrometry(3).
Plant Concentrations: 2- and 3-Xylene were detected, not quantified, in the volatiles of kiwi fruit flowers(1).
Fish/Seafood Concentrations: Xylene was detected in rainbow trout from the Colorado river and carp obtained from Las Vegas Wash, NV at concns of 50 and 120 ppb respectively(1).
Milk Concentrations: ENVIRONMENTAL POLLUTANTS IN HUMAN MILK WERE IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. XYLENE WAS ONE OF THE AROMATICS IDENTIFIED. Unspecified amounts of xylenes were identified in human milk by gas chromatography/mass spectrometry(1). Unspecified concns of xylenes were detected in mother's milk in Bayonne, NJ; Jersey City, NJ; Baton Rouge, LA; Pittsburgh, PA; Charleston, WV(2).
Environmental Standards & Regulations:
FIFRA Requirements: Xylene is exempted from the requirement of a tolerance when used as an aquatic herbicide applied to irrigation conveyance systems in accordance with the following conditions: (a) It is to be used only in programs of the Bureau of Reclamation, US Department of Interior and cooperating water user organizations. (b) It is to be applied as an emulsion at an initial concn not to exceed 750 ppm. (c) It is not to be applied when there is any likelihood that the irrigation water will be used as a source of raw water for a potable water system or where return flows of such treated irrigation water into receiving rivers and streams would contain residues of xylene in excess of 10 ppm. (d) Xylene to be used as an aquatic herbicide shall meet the requirement limiting the presence of a polynuclear aromatic hydrocarbons as listed in 172.250 of title 21, Code of Federal Regulations. /Xylene/ As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their future use. Under this pesticide reregistration program, EPA examines health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether they are eligible for reregistration. In addition, all pesticides must meet the new safety standard of the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA, as amended in 1988, were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern and List D pesticides of less concern. Xylene is found on List C. Case No: 3020; Pesticide type: insecticide; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Xylene; AI Status: Registrants of the pesticide have not made or honored a commitment to seek reregistration, conduct the necessary studies, or pay the requisite fees, or they have asked EPA to cancel their product registrations. Unless some other interested party supports them, products containing the pesticide will be cancelled.
CERCLA Reportable Quantities: Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802; In the Washington D.C. metropolitan area (202) 426-2675. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).
RCRA Requirements: F003; When xylene is a spent solvent, it is classified as a hazardous waste from a nonspecific source (F003), as stated in 40 CFR 261.31, and must be managed according to State and/or Federal hazardous waste regulations. U239; As stipulated in 40 CFR 261.33, when xylene, as a commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product or a manufacturing chemical intermediate, becomes a waste, it must be managed according to Federal and/or State hazardous waste regulations. Also defined as a hazardous waste is any residue, contaminated soil, water, or other debris resulting from the cleanup of a spill, into water or on dry land, of this waste. Generators of small quantities of this waste may qualify for partial exclusion from hazardous waste regulations (40 CFR 261.5).
Atmospheric Standards: Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Xylenes are included on this list.
Clean Water Act Requirements: Designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance.
Federal Drinking Water Standards: EPA 10000 ug/l
Federal Drinking Water Guidelines: EPA 10000 ug/l
State Drinking Water Standards: (NJ) NEW JERSEY 1000 ug/l
State Drinking Water Guidelines: (AZ) ARIZONA 440 ug/l (ME) MAINE 14,000 ug/l (MN) MINNESOTA 10000 ug/l
Allowable Tolerances: Xylene is exempted from the requirement of a tolerance when used as an aquatic herbicide applied to irrigation conveyance systems in accordance with the following conditions: (a) It is to be used only in programs of the Bureau of Reclamation, US Department of Interior and cooperating water user organizations. (b) It is to be applied as an emulsion at an initial concn not to exceed 750 ppm. (c) It is not to be applied when there is any likelihood that the irrigation water will be used as a source of raw water for a potable water system or where return flows of such treated irrigation water into receiving rivers and streams would contain residues of xylene in excess of 10 ppm. (d) Xylene to be used as an aquatic herbicide shall meet the requirement limiting the presence of a polynuclear aromatic hydrocarbons as listed in 172.250 of title 21, Code of Federal Regulations. /Xylene/ Residues of xylene are exempted from the requirement of a tolerance when used as a solvent and cosolvent (limits: pesticide formulations for grain storage only) in accordance with good agricultural practices as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest. /Xylene/ Xylene is exempted from the requirement of a tolerance when used as a solvent and cosolvent in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops only. /Xylene/
Chemical/Physical Properties:
Molecular Formula: C8-H10
Molecular Weight: 106.16
Color/Form: Colorless liquid
Odor: Sweet odor
Boiling Point: 137-140 DEG C
Corrosivity: Xylene will attack some forms of plastics, rubber, and coatings.
Density/Specific Gravity: 0.864 @ 20 DEG C/4 DEG C
Octanol/Water Partition Coefficient: log Kow= 3.12-3.20
Solubilities: PRACTICALLY INSOL IN WATER; MISCIBLE WITH ABSOLUTE ALCOHOL, ETHER, AND MANY OTHER ORGANIC LIQUIDS
Vapor Pressure: 7.99 mm Hg at 25 deg C /from experimentally derived coefficients/
Other Chemical/Physical Properties: Xylene can be easily chlorinated, sulfonated, or nitrated.
Chemical Safety & Handling:
Hazards Summary: The major hazards encountered in the use and handling of xylene stem from its toxicologic properties and flammability. Exposure to this clear, sweet-smelling liquid may occur during its use as a solvent for paints, coatings, adhesives, and rubber and as a component of gasoline. Toxic by all routes of exposure (ie, dermal, ingestion, and inhalation), xylene can cause effects including headache, dizziness, skin and eye irritation, kidney and liver impairment, to pulmonary edema, coma, and death. The ACGIH recommends a workplace exposure limit (TLV) of 100 ppm as an 8-hr time-weighted average (TWA); however, to assure protection, wear Buna-N-rubber gloves, apron, and safety glasses. In unknown concentrations or emergency situations, an approved organic vapor cannister respirator with a full-face plate or self-contained breathing apparatus and full protective clothing are recommended. If contact does occur, immediately flush exposed eyes with running water, wash exposed skin with soap and water, and remove contaminated clothing. Xylene is ignitable by heat, sparks, and flame and may do so explosively in an enclosed area. Also, vapor may travel a considerable distance to a source of ignition, and flash back. The heat of a fire may cause containers to explode and/or cause thermal degradation of xylene, producing irritating or poisonous gases. Fires involving xylene may be extinguished with dry chemical, CO2, water spray, fog, or foam. For massive fires in enclosed areas, use unmanned hose holders or monitor nozzles. If a xylene tank car or truck is involved in a fire, isolate 1/2 mile in all directions. Runoff from fire control water may cause pollution, and upon entering a sewer, may create an explosion hazard. Xylene substance should be stored in cool, well-ventilated places, away from sources of ignition and strong oxidizing materials. ... For small spills of xylene, take up with sand or other non-combustible absorbent, and place in containers for later disposal, or absorb on paper and evaporate in an appropriate exhaust hood. For large spills on land, dike to contain or divert to impermeable holding area (water spray may need to be applied to control flammable vapor) and remove material with pumps or vacuum equipment. Absorb residual with sand, vermiculite, or activated carbon and place in metal containers with covers. For large spills on water, contain material with booms, weirs, or natural barriers. Apply a universal gelling agent, and use (oil) skimming equipment or suction hoses to remove slick and trapped, solidified mass. Prior to implementing land disposal of waste residue (including waste sludge), consult environmental regulatory agencies.
DOT Emergency Guidelines: /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Health: May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Evacuation: Large spill: Consider initial downwind evacuation for at least 300 meters (1000 feet). Fire: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Fire: CAUTION: All these products have a very low flash point: Use of water spray when fighting fire may be inefficient. Small fires: Dry chemical, CO2, water spray or regular foam. Large fires: Water spray, fog or regular foam. Do not use straight streams. Move containers from fire area if you can do it without risk. Fire involving tanks or car/trailer loads: Fight fire from maximum distance or use unmanned hose holders or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ Spill or Leak: ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean non-sparking tools to collect absorbed material. Large spills: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor; but may not prevent ignition in closed spaces. /Xylenes/ /GUIDE 130: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE/NOXIOUS)/ First Aid: Move victim to fresh air. Call 911 or emergency medical service. Give artificial respiration if victim is not breathing. Administer oxygen if breathing is difficult. Remove and isolate contaminated clothing and shoes. In case of contact with substance, immediately flush skin or eyes with running water for at least 20 minutes. Wash skin with soap and water. Keep victim warm and quiet. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. Effects of exposure (inhalation, ingestion or skin contact) to substance may be delayed. Ensure that medical personnel are aware of the material(s) involved and take precautions to protect themselves. /Xylenes/
Odor Threshold: The odor threshold was calculated as 4.5 mg/cu m or about 1 ppm for a 10-sec exposure.
Skin, Eye and Respiratory Irritations: Xylene vapor may cause irritation of the eyes, nose, and throat. At high concentrations, xylene vapor may cause severe breathing difficulties which may be delayed in onset. Repeated or prolonged exposure ... may cause a skin rash. Vapor irritates eyes and mucous membranes and may cause dizziness, headache, nausea, and mental confusion. Liquid irritates eyes and mucous membranes.
NFPA Hazard Classification: Health: 2. 2= Materials hazardous to health, but areas may be entered freely with self-contained breathing apparatus. Flammability: 3. 3= Liquids which can be ignited under almost all normal temp conditions. Water may be ineffective on these liq because of their low flash points. Solids which form coarse dusts, solids in shredded or fibrous form that create flash fires, solids that burn rapidly, usually because they contain their own oxygen, and any material that ignites spontaneously at normal temp in air. Reactivity: 0. 0= Materials which are normally stable even under fire exposure conditions and which are not reactive with water. Normal fire fighting procedures may be used.
Fire Fighting Procedures: Use water spray or fog to extinquish fire. Cool fire exposed containers with water. If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped or safely confined. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use foam, dry chemical, or carbon dioxide.
Firefighting Hazards: Vapors are heavier than air & may travel to a source of ignition & flashback. Electrical hazard: class 1, group D
Hazardous Reactivities & Incompatibilities: An attempt to chlorinate xylene with 1,3-dichloro-5,5-dimethyl-2,4-imidazolidindione (dichlorohydrantoin) caused a violent explosion. The haloimide undergoes immediate self accelerating decomp in the presence of solvents. Incompatible with strong oxidizers.
Hazardous Decomposition: When heated to decomposition, it emits acrid smoke and fumes.
Prior History of Accidents: The wreck of the MV Ariadne, a Panamanian flag container ship, is examined as a case study of a hazardous substance emergency response in a third world country. /The ship/, carrying a cargo of heavy fuel oil, tetraethyl lead, xylene, toluene, methyl isobutyl ketone, butyl acetate, ethyl acetate, and acetone was grounded while departing the harbor of Mogadishu, Somalia. The Somalian government requested a team of technical advisors to help respond appropriately to the emergency. The major issues addressed by the advisory team were the need for additional salvage equipment and expertise, the danger of toxic fumes from the fire and explosions aboard the ship, the presence and possible release of tetraethyl lead, possible port blockage by the wreck, recovery of the chemical drums, and the extent of environmental damage caused by the release of oil, pesticides, and tetraethyl lead into the harbor. ...
Protective Equipment & Clothing: Employees should be provided with and required to use impervious clothing, gloves, face shields (eight-inch minimum) ... to prevent repeated or prolonged skin contact with liquid or solid xylene. Clothing contaminated with xylene should be placed in closed containers for storage until it can be discarded or until provision is made for the removal of xylene from the clothing. If the clothing is to be laundered ... the person performing the operation should be informed of xylene's hazardous properties. Breakthrough times /for natural rubber, neoprene, and polyvinyl chloride/ less (usually significantly less) than one hr reported by (normally) two or more testers. Breakthrough times /for polyvinyl alcohol/ greater than one hr reported by (normally) two or more testers. Some data suggesting breakthrough times /for nitrile rubber/ or approx an hour or more.
Preventive Measures: Skin that becomes contaminated with xylene should be promptly washed with soap or mild detergent and water to remove any xylene. Employees who handle liquid or solid xylene should wash their hands thoroughly with soap or mild detergent and water before eating, smoking, or using toilet facilities. A major concern in the painting studio is solvents, /including xylene/. ... Precautions include ... use of dilution and local exhaust ventilation, control of storage areas, disposal of solvent soaked rags in covered containers, minimizing skin exposure and the use of respirators and other personal protective equipment. The control of fire hazards is also important, since many of the solvents are highly flammable. Contact lenses should not be worn when working with this chemical. SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place. SRP: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. All contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning. If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to knock-down vapors. /Xylenes/ Personnel protection: Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. ...
Shipment Methods and Regulations: No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./ The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials. The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.
Storage Conditions: XYLENE SHOULD BE STORED IN COOL, WELL-VENTILATED PLACES, AWAY FROM AREAS OF ACUTE FIRE HAZARD, OPEN FLAMES & STRONGLY OXIDIZING MATERIALS. ALL CONTAINERS SHOULD BE CLEARLY LABELLED & KEPT TIGHTLY CLOSED.
Cleanup Methods: 1. REMOVE ALL IGNITION SOURCES. 2. VENTILATE AREA OF SPILL OR LEAK. 3. FOR SMALL QUANTITIES, ABSORB ON PAPER TOWELS. EVAPORATE IN SAFE PLACE (SUCH AS FUME HOOD). ALLOW SUFFICIENT TIME FOR EVAPORATING VAPORS TO COMPLETELY CLEAR HOOD DUCTWORK. BURN PAPER IN SUITABLE LOCATION AWAY FROM COMBUSTIBLE MATERIALS. LARGE QUANTITIES CAN BE RECLAIMED OR COLLECTED & ATOMIZED IN SUITABLE COMBUSTION CHAMBER. XYLENE SHOULD NOT BE ALLOWED TO ENTER CONFINED SPACE, SUCH AS SEWER. ... For spills on land, absorb remaining xylene with sand or vermiculite and put in metal containers for disposal. Activated carbon may be used on undissolved portion. For spills on water, contain and apply a universal gelling agent to solidify trapped mass then remove it. Soil: construct barriers to contain spill or divert to impermeable holding area. Remove material with pumps or vacuum equipment. Absorb residual liquid with natural or synthetic sorbents, shovel into containers with covers. Water: contain with booms, weirs, or natural barriers. Use (oil) skimming equipment or suction hoses to remove slick, followed by application of sorbents. Air: use water spray to control flammable vapor. Control runoff for later treatment and/or disposal. /Small quantities:/ Shut off all possible sources of ignition. Wear face shield, goggles, laboratory coat, and nitrile rubber gloves. Cover spill with a 1:1:1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite) and sand, then shovel into bucket and transport to fume hood for atmospheric evaporation. Ventilate site of spillage well to evaporate remaining liquid and dispel vapor. Environmental considerations - air spill: Apply water spray or mist to knock down vapors. Environmental considerations - water spill: Use natural barriers or oil spill control booms to limit spill travel. Use surface active agent (eg, detergent, soaps, alcohols), if approved by EPA. Inject "universal" gelling agent to solidify encircled spill and increase effectiveness of booms. If dissolved, in region of 10 ppm or greater concentration, apply activated carbon at ten times the spilled amount. Remove trapped material with suction hoses. Use mechanical dredges or lifts to remove immobilized masses of pollutants and precipitates. Environmental considerations - land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, or commercial sorbents. Apply "universal" gelling agent to immobilize spill. Apply appropriate foam to diminish vapor and fire hazard.
Disposal Methods: Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U239 and F003, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste. Xylene is a waste chemical stream constituent which may be subjected to ultimate disposal by controlled incineration. Chemical Treatability of Xylene; Concentration Process: Biological traetment; Chemical Classification: Aromatic; Scale of Study: Full scale, continuous flow; Type of Wastewater Used: Industrial; Results of Study: Influent concn of 20-200 ppb decreased to 1.0-15.0 ppb effluent concn in survey of two municipal wastewater treatment plants. A good candidate for fluidized bed incineration at a temperature range of 450 to 980 deg C and residence times of seconds for liquids and gases, and longer for solids. A good candidate for rotary kiln incineration at a temperature range of 820 to 1,600 deg C and residence times of seconds for liquids and gases, and hours for solids. A good candidate for liquid injection incineration at a temperature range of 650 to 1,600 deg C and a residence time of 0.1 to 2 seconds. The permeability of xylene in fire clay has been observed to sharply increase over a 4-day period after 24 days of normal behavior. This has been attributed to slow shrinkage of the clay which was responsible for the breakthrough. This type of breakthrough in clay would be a problem unless such materials are co-disposed with materials with higher dielectric constants.
Occupational Exposure Standards:
OSHA Standards: Permissible Exposure Limit: Table Z-1 8-hr Time Weighted Avg: 100 ppm (435 mg/cu m). /Xylenes (o-, m-, p- isomers)/ Vacated 1989 OSHA PEL TWA 100 ppm (435 mg/cu m); STEL 150 ppm (655 mg/cu m) is still enforced in some states. /Xylenes (o-, m-, p- isomers)/
Threshold Limit Values: 8 hr Time Weighted Avg (TWA): 100 ppm; 15 min Short Term Exposure Limit (STEL): 150 ppm /Xylene (o-, m-, & p- isomers)/ Biological Exposure Index (BEI): Determinant: Methylhippuric acids in urine; Sampling Time: end of shift; BEI: 1.5 g/g creatinine. /Xylenes, technical grade/ A4; Not classifiable as a human carcinogen. /Xylene (o-,m-, & p- isomers)/
Other Occupational Permissible Levels: Maximum acceptable concentration (MAC) USSR 50 mg/cu m
Manufacturing/Use Information:
Major Uses: RAW MATERIAL FOR PRODUCTION OF BENZOIC ACID; AS SOLVENT; MANUFACTURING DYES & OTHER ORGANICS; STERILIZING CATGUT; PRODUCTION OF PHTHALIC ANHYDRIDE, ISOPHTHALIC & TEREPHTHALIC ACIDS & THEIR DIMETHYL ESTERS USED IN MANUFACTURE OF POLYESTER FIBERS; WITH CANADA BALSAM AS OIL-IMMERSION IN MICROSCOPY; CLEANING AGENT IN MICROSCOPE TECHNIQUE Manufacture of resins, paints, varnishes, general solvent for adhesives IN AVIATION GASOLINE; PROTECTIVE COATINGS; SYNTHESIS OF ORG CHEMICALS SOURCE OF O-XYLENE, M-XYLENE, P-XYLENE & ETHYLBENZENE SOLVENT-EG, FOR PAINTS, COATINGS, ADHESIVES & RUBBER BACK-BLENDED INTO GASOLINE UNRECOVERED COMPONENT OF GASOLINE Used in manufacture of quartz crystal oscillators, hydrogen peroxide, perfumes, insect repellants, epoxy resins, pharmaceuticals, and in the leather industry. /SRP:/ Used in histological laboratories. Used as a solvent in phenoxyalkanoic herbicides. (MEDICATION) Used in manufacture of ... pharmaceuticals ... . Used as an indirect food additive for use only as a component of adhesives. Used as an indirect food additive polymer for use as a basic component of single and repeated use food contact surfaces. Xylene is used as a solvent in polysulfide polymer-polyepoxide resins.
Manufacturers: Amoco Corp, Hq, 200 East Randolph Dr, Chicago IL 60601, (312) 856-6111; Production sites: Amoco Oil Co, subsidiary, PO Box 401, Texas City, TX 77590; subsidiary, Amoco Chemicals Co, PO Box 710, Whiting, IN 46394 Ashland Oil, Inc, Hq, 1401 Winchester Ave, Ashland, KY 41101, (606) 329-3333; Production site: Ashland Chemical Co, Div, Petrochemicals Div, Leach Station, Catlettsburg, KY 41129 BP Oil, 200 Public Square, Cleveland, OH 44114-2375, (216) 586-4141. Production site: Alliance, LA 70037 Chevron Corp, Hq, 225 Bush St, San Francisco, CA 94104, (415) 894-7700; Production site: subsidiary, Chevron Chemical Co, Aromatics and Derivatives Div, Pascagoula, MS 39567 Citgo Petroleum Corporation, 6130 South Yale Avenue, Tulsa, OK 74136, (918) 495-5000. Production site: Chorpus Christi, TX 78469 Coastal Eagle Point Oil Company, PO Box 1000, US Route 130&I-296, Westville, NJ 08093,(609) 853-3100. Production site: Westville, NJ 08093 Coastal Refining and Marketing Company, 9 Greenway Plaza, Houston, TX 77046, (713) 877-7174. Production site: Chorpus Christi, TX 78403 Exxon Corp, Hq, 1251 Avenue of Americas, New York, NY 10020, (212) 398-3000; Production site: Exxon Chemical Co, div, Exxon Chemical Americas, PO Box 4004, Baytown, TX 77520 Fina Oil and Chemical Company, PO Box 2159, Dallas TX, 75221, (214) 750-2400. Production site: Port Arthur, TX, 77640 Hess Oil Virgin Islands Corp, PO Box 127, Kingshill, VI, 00851-0127. Phone (809)778-4000. Production site: St. Croix, VI, 00851 Koch Industries, Inc, Hq, PO Box 2256, Wichita, KS 67201, (316) 832-5500; Production site: subsidiary, Koch Refining Co, Corpus Christi, TX 78403 Lyondell-Citgo Refining Company LTD, 12000 Lawndale, Houston TX 77017. (713) 321-4111. Production site: Houston, TX 77017 Marathon Oil, PO Box 3128, Houston, TX 77253, (713) 629-6600. Production site: Texas City, TX 77592-1191 Mobil Chemical Company, Petroleum Division, 3225 Gallows Road, Fairfax, VA 22037-0001. (703) 846-3000. Production sites: Beaumont, TX 77704-0216; Chalmette, Louisiana 70043 Phillips Petroleum Co, Hq, Phillips Building, Bartlesville, OK 74004, (918) 661-6600; Production sites: subsidiary, Phillips 66 Co, Chemicals and Catalysts Div, Specialty Chemicals, PO Box 308, Sweeny, TX 77480; subsidiary, Phillips Puerto Rico Core Inc, Guayama, Puerto Rico 0065 Shell Oil Co, Hq, One Shell Plaza, Houston, TX 77001, (713) 241-6161; Production site: Shell Chemical Co, division, PO Box 100, Deer Park, TX 77536 Sun Company, Inc, Hq, 240 Radnor-Chester Road, St Davids, PA 19087, (215) 293-6000; Production sites: subsidiary, Sun Refining and Marketing Co, PO Box 426, Marcus Hook, PA 19061; subsidiary, Sun Refining and Marketing Co, PO Box 920, Toledo, OH 43601 The UNO-VEN Company, 3850 North Wilke Road, Arlington Heights, IL 6000. (708) 818-1800. Production site: Lemont, IL 60439-3659
Methods of Manufacturing: FIRST ISOLATED FROM A CRUDE WOOD DISTILLATE. OBTAINED FROM COAL TAR. ... MFR FROM PSEUDOCUMENE; BY CATALYTIC ISOMERIZATION OF HYDROCARBON FRACTION. ... FROM TOLUENE BY TRANSALKYLATION. RECOVERY FROM PETROLEUM-DERIVED CATALYTIC REFORMATE OR PYROLYSIS OF GASOLINE; DISPROPORTIONATION OF TOLUENE; RECOVERY FROM CRUDE LIGHT OIL (BY-PRODUCT OF COKE MFR)
General Manufacturing Information: The commerical product mixed xylenes (a technical product generally containing 20% each of o-xylene, p-xylene and ethylbenzene, as well as small quantities of toluene) analogously to toluene is an agent of major chemical and occupational significance. It is produced in very large quantities and is extensively employed in a broad spectrum of applications, primarily as a solvent for which its use is increasing as a safe replacement for benzene, and in gasoline as part of the BTX component (benzene-toluene-xylene); xylenes are also frequently used in the rubber industry with other solvents such as toluene and benzene. As individual isomers they are extensively employed in the synthesis of synthetic agents. For example, phthalic acid, isophthalic acid, terephthalic acid, and diemthylterephthalate have very broad applications in the further preparation of phthalate ester plasticizers and components of polyester fiber, film and fabricated items. ... Compared with benzene and toluene, very much less is known of the human health hazards, particularly the chronic effects of xylenes, either as mixed xylenes, as individual isomers or in admixture with other alkylbenzenes. ... Xylene produced from petroleum ... contains approx 20% o-xylene, 44% m-xylene, 20% p-xylene and 15% ethylbenzene. Xylene from coal tar generally consists of 10-15% ortho-, 45-70% meta-, 23% para-, and 6-10% ethylbenzene.
Formulations/Preparations: The commercial product "mixed xylenes" is a technical product generally containing approximately 40% m-xylene and 20% each of o-xylene, p-xylene, and ethylbenzene, as well as small quantities of toluene ... . 70% of all mixed xylene grades produced are 3 deg and 5 deg grade. Solvent xylene, 2 deg C range Grade: Nitration (bp range 137.2-140.5 deg C), 4 degrees (bp range 138-134 deg C), 5 degrees (bp range 137-142 deg C, high in m- isomer), 10 degrees (bp range 135-145 deg C); industrial (bp 90% 40 deg C, complete 160 deg C). Also other grades depending upon use.
Impurities: ... Commercial xylenes may contain small amt of toluene, trimethylbenzene, phenol, thiophene, pyridine, and nonaromatic hydrocarbons. Unpurified xylene may contain ... pseudocumene ... . The possibility that commercial xylene may ... contain benzene should not be ignored.
Consumption Patterns: SOURCE OF P-XYLENE, 61.7%; SOURCE OF O-XYLENE, 12.3%; SOLVENT FOR PAINTS & COATINGS, 5.7%; OTHER SOLVENT USES, 3.1%; SOURCE OF ETHYLBENZENE, 3.1%; SOURCE OF M-XYLENE, 0.9%; GASOLINE BACK-BLENDING & MISCELLANEOUS, 13.2% (1980 RECOVERED USE) Ortho-xylene, 15%; para-xylene, 60%; miscellaneous, 14%; exports, 11% (1982) /estimate/ (1993) 2.99X10+9 kg
U. S. Production: (1982) 657,964,000 gal (1981) 882,408,000 gal (1967) 454,837,000 gal (1977) 2.80X10+12 G (1982) 2.27X10+12 G (1985) 2.38X10+12 g (1985) 2.03X10+12 g /high purity 98-100%/ (1987) 7.95X10+8 gal (1990) 6.21 billion lb (1991) 6.32 billion lb (1992) 6.39 billion lb (1993) 6.84 billion lb 9.37 billion lb
U. S. Imports: (1977) 1.04X10+11 G (1982) 1.31X10+11 G (1984) 4.57X10+8 g /calculated/ (1985) 7.09X10+7 gal (1986) 7.50X10+7 gal
U. S. Exports: (1977) 2.77X10+11 G (1982) 2.83X10+11 G (1985) 3.41X10+7 gal (1987) 4.75X10+7 gal
Laboratory Methods:
Clinical Laboratory Methods: Quantitative determination of urinary metabolites exposed to xylene using colorimetric determination is widely used. The metabolites of ... xylene are measured as ... methyl hippuric acid (MHA), paper chromatography and thin-layer chromatography are necessary as pretreatments of samples. The addition of pyridine, p-dimethylaminobenzaldehyde (DAB) and acetic anhydride to glycine conjugates gives the most stable color development. Excellect analytical sensitivity and specificity with gas chromatographic methods requires pretreatment with diazomethane for methylesterification of methyl hippuric acid. High performance liquid chromatography has been widely used for analysis of organic solvents. Non-volatile metabolites in urine can be assayed by this method without pretreatment. ... Phenolic metabolites /of xylene/ were quantitatively estimated in hydrolyzed urine samples by gas chromatography.
Analytic Laboratory Methods: ANALYTE: XYLENE; MATRIX: AIR; PROCEDURE: ADSORPTION ON CHARCOAL, DESORPTION WITH CARBON DISULFIDE, GAS CHROMATOGRAPHY; RANGE: 218-870 MG/CU M; PRECISION: COEFFICIENT OF VARIATION 0.060. ORGANIC GASES WERE COLLECTED IN TUBE FILLED WITH SOLID SORBENT. XYLENE WAS ONE OF THE GASES IDENTIFIED BY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. Commercial heterogeneous solvent products (eg paints, inks, and adhesives) were collected nationwide in Japan in 1980. The vapor phase of the product containers were analyzed for volatile organic solvent constituents by means of FID-gas chromatography on two FS-WCOT (OV-101 and PEG-600) capillary columns. ... Organic solvent components identified, ... /included/ xylenes /which were/ predominantly the m- (66%) and p- isomers. (61%) Results from the measurements of benzene, toluene, and xylenes in the city center of Oslo are presented. The samples were collected in March and August/September 1980 at two stations used in an air pollution monitoring program. The sampling equipment was two charcoal filters in series, placed in a filter holder with a disk of glass fiber prefilter in front. Analysis was by high resolution gas chromatography. The results of a successful test of remote fluorescence analysis of ground water contaminants by using uv lasers and fiber optics /is described/. Several priority pollutants /including/ xylenes were detected using this technique. Method TO-1: Method for the Determination of Volatile Organic Compounds in Ambient Air Using Tenax Adsorption and Gas Chromatography/Mass Spectrometry (GC/MS). Detection limit 1 ng. Method 8020A: Aromatic Volatile Organics by Gas chromatography Detection limit 1 ug/l. Method 8240A: Volatile Organics by Gas Chromatography/Mass Spectrometry(GC/MS): Packed Column Technique. Detection limit 5ug/l. EPA CLP Method OHC: Organic Analysis, Multi-Media, High Concns: Volatile Organics in air determined by methanol extraction and gas chromatography/flame ionization detection (GC/FID). Detection limit 2.5 mg/kg. EPA CLP Method Olm01: Organic Analysis, Multi-Media, High Concns: Volatile Organics in air determined by hexadecane extraction and gas chromatography/flame ionization detection (GC/FID). Detection limit 10 ug/l.
Sampling Procedures: Xylene vapor is trapped on charcoal from a known vol of air.
Special References:
Special Reports: Von Burg R; J Appl Toxicol 2: 269-71 (1982). A review article on the toxicity of xylene mixture and individual isomers. National Academy of Sciences; The Alkyl Benzenes (1981) Fishbein L; Sci Total Environ 43 (1-2): 165-83 (1985). A review article on the toxicology of xylenes. NIOSH; Criteria Document: Xylene (1975) DHEW Pub. NIOSH 75-168 USEPA; Drinking Water Criteria Document: Xylenes (1984) EPA-600/X-84-185. Bailey HC et al; ASTM Spec Tech Publ 891: 193-212 (1985) NCI; Monograph on Human Exposure to Chemicals in the Workplace: Xylene (July/1985) USEPA; Advisory Opinion for Xylenes (Dimethyl benzenes) (Draft) (1981) NIOSH; Recommendations for Occupational Safety and Health Standards 35 (1S) (1986) U.S. Dept Health & Human Services/Agency for Toxic Substances Disease Registry; Toxicological Profile for (Xylenes) (Update) (1995) NTIS# PB/95/264404 Toxicology & Carcinogenesis Studies of Xylenes in F344/N Rats and B6C3F1 Mice (gavage Studies). Technical Report Series No. 327 (1986) NTIS Publication No. PB87-189684/AS U.S. Department of Health and Human Services, National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
Synonyms and Identifiers:
Related HSDB Records: 134 [2-XYLENE] (Mixture Component) 135 [3-XYLENE] (Mixture Component) 136 [4-XYLENE] (Mixture Component)
Synonyms: AI3-02209-X BENZENE, DIMETHYL- Caswell No 906 DIMETHYLBENZENE EPA Pesticide Chemical Code 086802 KSYLEN (POLISH) Methyltoluene NCI-C55232 VIOLET 3 XILOLI (ITALIAN) XYLENEN (DUTCH) XYLENES XYLOL XYLOLE (GERMAN)
Formulations/Preparations: The commercial product "mixed xylenes" is a technical product generally containing approximately 40% m-xylene and 20% each of o-xylene, p-xylene, and ethylbenzene, as well as small quantities of toluene ... . 70% of all mixed xylene grades produced are 3 deg and 5 deg grade. Solvent xylene, 2 deg C range Grade: Nitration (bp range 137.2-140.5 deg C), 4 degrees (bp range 138-134 deg C), 5 degrees (bp range 137-142 deg C, high in m- isomer), 10 degrees (bp range 135-145 deg C); industrial (bp 90% 40 deg C, complete 160 deg C). Also other grades depending upon use.
Shipping Name/ Number DOT/UN/NA/IMO: UN 1307; Xylenes (Xylol) IMO 3.2; Xylenes IMO 3.3; Xylenes
Standard Transportation Number: 49 093 50; Xylenes
EPA Hazardous Waste Number: U239; A toxic waste when a discarded commercial chemical product or manufacturing chemical intermediate or an off-specification commercial chemical product. F003; A hazardous waste from nonspecific sources when a spent solvent. Top of Page Return to Home Page of Home Air Purifier Expert from Xylene Information Best Indoor Air Quality Test Kit for Xylene Testing New! CommentsHave your say about what you just read! Leave me a comment in the box below. |
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