CAS RN: 95-47-6

Health Effects

    • A) USES: Xylene is an aromatic hydrocarbon consisting of a benzene ring with 2 methyl substituents. It is widely used as a solvent in paint, printing inks, varnishes, dyes, cement and cleaning fluids. Xylene is also found in gasoline and aviation fuels. It is used in the manufacture of plastics, synthetic textiles, perfumes, insect repellants, epoxy resins, herbicides and pharmaceutical preparations.
    • B) TOXICOLOGY: Xylene is an aromatic hydrocarbon solvent that causes CNS depression and is an irritant of skin and mucus membranes. It preferentially accumulates in the brain and fatty tissue after inhalation. It has a lower volatility, lower affinity for the CNS, and a lower acute toxicity compared to toluene or benzene.
    • C) EPIDEMIOLOGY: Hundreds of exposures to aromatic hydrocarbons are reported to poison centers every year and exposure is common in certain petrochemical industries but serious toxicity is rare.
      • 1) INHALATION: Low concentrations are irritating to mucous membranes. Xylene may cause reversible hepatic and renal toxicity. High vapor concentrations can cause initial CNS excitation followed by narcosis, olfactory changes, respiratory tract irritation, and acute lung injury. Severe exposures may be fatal due to respiratory arrest and/or ventricular dysrhythmias.
      • 2) INGESTION: Minor ingestions can cause mucous membrane irritation, a burning sensation in the oropharynx and stomach and vomiting. Large ingestions can cause ventricular fibrillation, reversible hepatic and renal toxicity and CNS depression. Pulmonary aspiration can cause pneumonitis and acute lung injury.
      • 3) DERMAL: Exposure to xylene liquid can cause defatting of the skin with irritation, dryness, erythema, and cracking. Blistering may occur if exposure or concentrated xylene is prolonged.
      • 4) OCULAR: Exposure to high vapor concentrations of xylene can cause ocular irritation. Vacuolar keratopathy has occurred in a few workers with prolonged exposure to high vapor concentrations. Splash accidents produce transient superficial injury in most cases, though there are older reports of conjunctivitis and corneal burns following eye contact with liquid xylene.
      • 5) CHRONIC: Exposure to xylene may cause a defatting dermatitis, reversible eye damage, dyspnea, confusion, dizziness, apprehension, memory loss, headache, tremors, weakness, anorexia, nausea, tinnitus, irritability, thirst, liver function test abnormalities, renal impairment, and anemia. Xylene contaminated with benzene has been associated with blood dyscrasias.
  • A) There are few well-conducted studies of the reproductive effects of xylene exposure in humans. Very limited data suggest that toxicosis, miscarriage, hemorrhage during childbirth, and infertility may occur. There is evidence in experimental animals that xylene is embryotoxic, fetotoxic, and possibly teratogenic, usually at doses which cause maternal toxicity.
  • B) Human studies concerning the reproductive effects of xylene have limitations, in that exposures are usually to more than one solvent (benzene, toluene and other compounds are common), exposure data are often lacking and endpoints are not sufficiently specific.
    • A) IARC Carcinogenicity Ratings for CAS1330-20-7 (International Agency for Research on Cancer (IARC), 2016; International Agency for Research on Cancer, 2015; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2010a; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2008; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2007; IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, 2006; IARC, 2004):
      • 1) IARC Classification
        • a) Listed as: Xylenes
        • b) Carcinogen Rating: 3
      • 1) The agent (mixture or exposure circumstance) is not classifiable as to its carcinogenicity to humans. This category is used most commonly for agents, mixtures and exposure circumstances for which the evidence of carcinogenicity is inadequate in humans and inadequate or limited in experimental animals. Exceptionally, agents (mixtures) for which the evidence of carcinogenicity is inadequate in humans but sufficient in experimental animals may be placed in this category when there is strong evidence that the mechanism of carcinogenicity in experimental animals does not operate in humans. Agents, mixtures and exposure circumstances that do not fall into any other group are also placed in this category.
    • A) There is inadequate information concerning carcinogenic effects of xylene in humans. Non-Hodgkin's lymphoma has been potentially associated with exposure to solvents, including xylene. However, xylene is not regarded as a human carcinogen.
    • B) The EPA classifies xylenes as Group D (not classifiable as to human carcinogenicity), based on no human data and inadequate animal data (HSDB, 2002).
  • A) A National Toxicology Program review concluded that xylenes, in general, are not mutagenic and do not produce genotoxic effects. One study reported a weak mutagenic response in the Drosophila sex-linked recessive lethal test with a commercial xylene mixture.
  • B) Studies reviewed in the IRIS database (199
    • 5) also failed to demonstrate genotoxic/mutagenic effects. No increased frequency of sister chromatid exchanges or chromosomal aberrations was identified in xylene exposed workers or in human lymphocytes exposed to xylene in vitro.
  • C) CASE-CONTROL STUDY - No increased sister chromatid exchanges were identified in the peripheral lymphocytes of 46 workers exposed to mean xylene concentrations of 47.3 mg/m(
    • 3) or 55.9 mg/m(
    • 3) measured weekly over 1 year.
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