• What are the main health hazards associated with breathing in xylene?
• What happens when xylene comes into contact with my skin?
• Can xylene hurt my eyes?
• What happens if xylene is accidentally swallowed (enters the digestive system)?
• What are the long term health effects of exposure to xylene?
• Will xylene cause cancer?
• Will xylene cause any problems with my reproductive system?
• Will xylene cause effects on the fetus/unborn baby?
• Will xylene act in a synergistic manner with other materials (that is, will its effects be more than the sum of the effects from the exposure to each chemical alone)?
• Is there potential for xylene to build-up or accumulate in my body?

What are the main health hazards associated with breathing in xylene?

The main effect of inhaling xylene vapour is depression of the central nervous system (CNS), with symptoms such as headache, dizziness, nausea and vomiting. Volunteers have tolerated 100 ppm, but higher concentrations become objectionable. Irritation of the nose and throat can occur at approximately 200 ppm after 3 to 5 minutes. Exposures estimated at 700 ppm have caused nausea and vomiting. Extremely high concentrations (approximately 10000 ppm) could cause incoordination, loss of consciousness, respiratory failure and death. In some cases, a potentially fatal accumulation of fluid in the lungs (pulmonary edema) may result. Symptoms of pulmonary edema, such as shortness of breath and difficulty breathing, may be delayed several hours after exposure. However, these effects are rarely seen since xylene is irritating and identifiable by odour at much lower concentrations. The only reported death resulted from exposure to xylenes (unspecified isomer composition and unknown concentration) in a confined space. Reversible liver and kidney damage has been reported in cases of severe xylene exposure. Results of short-term studies on human volunteers indicate that xylenes can cause neurobehavioural effects such as impaired short-term memory and reaction time (300 ppm xylene, with exercise) and alterations in body balance (65 to 400 ppm m-xylene). Exposure to 300 or 400 ppm xylene or 65 to 150 ppm p-xylene have not had similar effects. This variation in results is probably due to differences in the effects being studied, exposure conditions, development of tolerance and total xylene uptake (which increases during exercise).

What happens when xylene comes into contact with my skin?

Studies with xylene isomers have shown irritation, redness and a burning sensation can result from contact. These effects are reversible shortly (usually within 1 hour) after the contact stops. Repeated or prolonged exposure to xylene can defat the skin resulting in dermatitis (red, dry, itchy skin).

Xylene liquid or vapour can be absorbed through the skin, but not as readily as when inhaled or ingested. Significant harmful effects are not expected by this route of exposure.

Can xylene hurt my eyes?

The liquid is probably a mild irritant, based on animal information. Eye irritation has been reported at vapour levels as low as 200 ppm. Corneal vacuoles (pockets of fluid or air in the cornea) have also been reported following exposure to undefined vapour concentrations. This effect was reversible within 8 to 11 days for 7 of 8 workers.

What happens if xylene is accidentally swallowed (enters the digestive system)?

Based on animal information, xylene is only slightly toxic by ingestion. Ingestion of large amounts is likely to cause CNS effects such as dizziness, nausea and vomiting. In one case, ingestion of food probably contaminated with xylene caused pulmonary edema, liver impairment and coma. The man recovered within 2 hours after treatment. Ingestion is not a common route of occupational exposure.

Although there are no case reports, xylene may be aspirated, based on its physical properties (viscosity and surface tension). Aspiration is the inhalation of a material into the lungs during ingestion or vomiting. Severe lung irritation, damage to the lung tissues and death may result.

What are the long term health effects of exposure to xylene?

SKIN: Repeated contact can produce dermatitis (dryness and cracking) due to degreasing action.

SKIN SENSITIZATION: Skin sensitization was not produced in any of 24 volunteers. There is one case report of a person developing an allergic skin reaction (contact urticaria) following exposure to xylene (unspecified composition) vapour. The person subsequently tested positive in a patch test. No information was provided regarding previous history of allergies. No conclusions can be drawn regarding the potential for xylene to produce allergic skin reactions, based on this single case report.

NERVOUS SYSTEM EFFECTS: Long-term xylene exposure may cause harmful effects on the nervous system, but there is not enough information available to draw firm conclusions. Symptoms such as headaches, irritability, depression, insomnia, agitation, extreme tiredness, tremors, and impaired concentration and short-term memory have been reported following long-term occupational exposure to xylene and other solvents. This condition is sometimes generally referred to as "organic solvent syndrome". Unfortunately, there is very little information available which isolates xylene from other solvent exposures in the examination of these effects. Other study deficiencies include inadequate reporting on the duration of exposure and the exposure levels, and poor matching of controls.

In a recent study, 175 employees were exposed to an average xylene concentration of 21 ppm for an average of 7 years. Subjective symptoms such as anxiety, forgetfulness, inability to concentrate and dizziness were reported. Xylenes accounted for greater than 70% of the total exposure.) This study is also limited by factors such those described above.

BLOOD EFFECTS: Historical reports sometimes associate xylene exposure with certain blood effects, including leukemia, which are now known to be caused by benzene. Uncontaminated xylene is not known to cause these effects. Reduced blood platelet counts were observed in 12 of 27 men exposed to xylene (unspecified composition) at a level up to 200 ppm. When exposure stopped, platelet counts returned to normal. There is insufficient information to draw any conclusions from this study.

LIVER AND KIDNEY EFFECTS: A number of case reports and occupational studies have suggested that liver and kidney damage may result from long-term occupational exposure to xylene. However, it is not possible to attribute these effects directly to xylene exposure because generally there was exposure to other chemicals at the same time, particularly other solvents, and there was no information provided on the exposure levels or duration of exposure.

In a recent study, 175 employees were exposed to a mean xylene concentration of 21 ppm for an average of 7 years. Liver and kidney effects were not reported. Xylenes accounted for greater than 70% of the total exposure.

Will xylene cause cancer?

There are two case-control studies investigating the relationship between cancer and xylene exposure. However, in both studies, there was exposure to other chemicals and the number of cases was limited. The International Agency for Research on Cancer (IARC) has determined that there is inadequate evidence for the carcinogenicity of xylene in humans. No conclusions can be drawn from the available animal information.

OVERALL IARC EVALUATION: Xylene is not classifiable as to its carcinogenicity to humans (Group 3)

Will xylene cause any problems with my reproductive system?

An increase in menstrual disorders has been reported in women exposed to organic solvents such as benzene, toluene and xylene. It is not possible to attribute these effects to xylene in particular. The limited animal information available suggests that xylene does not cause reproductive effects.

Will xylene cause effects on the fetus/unborn baby?

Several human population studies have suggested a link between exposure to organic solvents (including xylene) and increased occurrence of miscarriages or birth defects in children. However, in the majority of cases, there was exposure to a variety of solvents at the same time, exposures were ill-defined, and the number of cases examined was small. Overall, no conclusions can be made on the effects of exposure to xylene on the unborn child because of the inadequacy of the available information.

Xylene has produced fetotoxic effects (delayed ossification and behavioural effects) in animals, in the absence of maternal toxicity. Animal information suggests that xylene is not teratogenic or embryotoxic at exposure levels that are not harmful to the mother.

Will xylene act in a synergistic manner with other materials (that is, will its effects be more than the sum of the effects from the exposure to each chemical alone)?

Exposure to related solvents, such as benzene, toluene and ethanol (alcohol) slows the rate of clearance of xylene from the body, thus enhancing its toxic effects. Exposure to xylene in combination with other solvents has had an additive effect with respect to harming the hearing of rats.

Is there potential for xylene to build-up or accumulate in my body?

The three xylene isomers are readily absorbed by inhalation and ingestion and are widely distributed throughout the body. A small amount may be absorbed through the skin. Xylene is largely broken down by the liver and most of the absorbed material is rapidly excreted in the urine as breakdown products. Smaller amounts are eliminated unchanged in the exhaled air. There is low potential for accumulation.

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Document last updated on September 25, 1998

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