Substance fact sheet
The background information page contains information and concepts that will be useful in understanding some of the issues surrounding the NPI. It is strongly recommended that you read this before reading the information presented below.
For an explanation of some of the terms used in this page, see the Glossary
| Substance name | Xylenes (individual or mixed isomers) |
| CASR number | 1330-20-7 |
| Molecular formula | C8H10 |
| Synonyms | Dimethylbenzene, Xylol, Dimethylbenzene (mixed isomers), Xylenes (o-, m-, p-isomers) m-xylene (CASR# 108-38-3), o-xylene (CASR# 95-47-6), p-xylene (CASR# 106-42-3) |
Physical and chemical properties Physical properties: Xylene is a colourless liquid, with a strong, sweet odour. Melting Point (°C):m-xylene -47.4; o-xylene -25.2; p-xylene 13-14; mixed -48 Boiling Point (°C): m-xylene 139.3; o-xylene 144.4; p-xylene 137; mixed 137 Specific Gravity: m-xylene 0.87; o-xylene 0.88; p-xylene 0.86; mixed 0.87 Chemical properties: |
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Common uses Xylene is used as a solvent, to manufacture petrol, as a raw material to manufacture chemicals used to make polyester fibre, and to make dyes, paints, lacquers, and insecticides. It is used to sterilize some materials. |
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Sources of emissions Point sources Chemical and petrol manufacture, polyester manufacture, manufacture of paints, dyes, and lacquers. Most xylene emissions will be to the air, unless there is a spill. Much of spilt xylene will end up as an airborne pollutant due to evaporation. Diffuse sources, and point sources included in aggregated emissions data Commercial and household painting, woodburning stoves, and fireplaces. These emissions are to the air. Natural sources m-xylene and p-xylene occur naturally in petroleum. o-Xylene is found in coal tar, petroleum, forest and bush fires, and plant emissions. Mobile sources Motor vehicles give off emissions to the air. Consumer products which may contain Xylenes (individual or mixed isomers) Xylenes are common in domestic products such as aerosol paints, architectural coatings, automobile and machinery paints and primers, caulks, insecticides and fungicides for yard and garden, hard surface cleaners, lubricating oils, markers, automotive chemicals, paints, varnish and paint and varnish removers and thinners, pet flea and tick products, pesticides, shoe polish, interior clear finishes, undercoats, and primers, sealants, resin and rubber adhesives, water proofing compounds, and wood office furniture. |
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Health effects How might I be exposed to Xylenes (individual or mixed isomers)? Consumers are most likely to be exposed to xylene from petrol, automotive exhaust or when using consumer products containing xylene, especially if there is not good ventilation. Because xylene is used in many consumer products, short-term indoor concentrations may be elevated above the levels considered safe for workers. Workers in the industries that use or produce xylene are at risk of exposure. Consumers can also be exposed to xylene by exposure to air from production and processing facilities using xylene. When xylene is released to the water or soil it will evaporate rapidly, this makes exposure from contaminated water unlikely. By what pathways might Xylenes (individual or mixed isomers) enter my body? Xylene will enter the body if we breathe in contaminated air, or breathe tobacco smoke. It can also be absorbed through the skin if liquid xylene is in contact with the skin. Relative health hazard On a health hazard spectrum of 0 - 3 Xylenes (individual or mixed isomers) registers 1.3. A score of 3 represents a very high hazard to health, 2 represents a medium hazard and 1 is harmful to health. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the evaluation of its tendency to cause, or not cause cancer and/or birth defects. It does not take into account exposure to the substance. Human exposure is reflected in the NPI rank given to this substance (see comparative data below). A substance that scores highly as a health hazard is arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.  Health guidelines Worksafe Australia The eight hour time weighted average (TWA) exposure limit is 80 parts per million, and the short term exposure limit (STEL) is 150 parts per million. Australian Drinking Water Guidelines (NHMRC and ARMCANZ, 1996): Health: Maximum of 0.6 mg/L (i.e. 0.0006 g/L). Aesthetics: Maximum of 0.02 mg/L (i.e. 0.00002 g/L). See the Additional Information page for current health information. The Australian NOHSC National Exposure Standards Database link is probably the most useful source of information. Note that the emissions data in the NPI database is not directly comparable with these guidelines. What effect might Xylenes (individual or mixed isomers) have on my health? Xylenes may irritate the eyes, nose and throat. They may cause stomach problems, drowsiness, loss of memory, poor concentration, nausea, vomiting, abdominal pain and incoordination. High levels may cause dizziness, passing out, and death. Repeated exposures may damage bone marrow, which causes a low blood cell count. Xylenes may damage a developing foetus. |
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Environmental effects Environmental Fate Most of the xylenes are released into the atmosphere where they are quickly degraded by sunlight. When released to soil or water they quickly evaporate. They may leach into the groundwater (bore water). Environmental Transport Industrial emissions of xylene can produce elevated, but still low level concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere xylene is expected to be confined to the local area within which it is emitted. Since it does not bind to soil well, xylene that makes its way into the ground may move through the ground and enter groundwater (bore water). Relative hazard to the environment On an environmental spectrum of 0 - 3 Xylenes (individual or mixed isomers) registers 1. A score of 3 represents a very high hazard to the environment and 0 a negligible hazard. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the measure of its ability to remain active in the environment and whether it accumulates in living organisms. It does not take into exposure to the substance. Environmental exposure is reflected in the NPI rank for this substance (see comparative data below). A substance that scores highly as an environmental hazard is oxides of nitrogen at 3.0 and one of the lower scores is carbon monoxide at 0.8.  Environmental guidelines See the Additional Information page for current environmental guidelines. No national guidelines. What effect might Xylenes (individual or mixed isomers) have on the environment? Xylene has high acute (short-term) toxicity to aquatic life. It causes injury to various agricultural and ornamental crops. It also has high chronic (long-term) toxicity to aquatic life. There is not sufficient data to predict the acute or chronic toxicity of xylene on birds or land animals. Xylene is expected to moderately bioaccumulate, in fish. |
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Comparative data NPI Rank Approximately 400 substances were considered for inclusion on the NPI reporting list. A risk ranking was given based on health and environmental hazard identification and human and environmental exposure to the substance. Some substances were grouped together at the same rank with 208 ranks in total. Xylenes (individual or mixed isomers) was ranked as 9 out of the 208 ranks. Total hazard score (human health + environmental criteria) = 2.3.  |
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Sources of information used in preparing this article
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