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The Complete Guide to XyleneXylene is a toxic solvent and Volatile Organic Compound (VOC) found in many common household products such as paints, laquers, adhesives, rust preventers, thinners, gasoline, and permanent magic markers. This guide includes FAQs, Public Health Statement, Material Safety Data, and Toxicology Information for Xylene. In case of emergencies involving Xylene contact your local emergency services or The National Poison Control Center (1-800-222-1222) from anywhere in the United States.
The above national hotline number will let you talk to experts in poisoning. They will provide further information about what to do in case of Xylene exposure. All local poison control centers in the U.S. use this national number. You should call if you have any questions about Xylene poisoning or Xylene poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week. Also, in case of suspected poisoning, take the container with you to the hospital, if possible. For more information, contact the American Association of Poison Control Centers --www.aapcc.org. 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. 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 |
