Xylenes (individual or mixed isomers)
Overview
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.
Substance details
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 properties
Xylene is a colourless liquid, with a strong, sweet odour.
Melting Point:
- m-xylene -47.4°C
- o-xylene -25.2°C
- p-xylene 13-14°C
- mixed -48°C
Boiling Point:
- m-xylene 139.3°C
- o-xylene 144.4°C
- p-xylene 137°C
- mixed 137°C
Specific Gravity:
- m-xylene 0.87
- o-xylene 0.88
- p-xylene 0.86
- mixed 0.87
Chemical properties
There are three xylenes: m-xylene (CASR# 108-38-3), o-xylene (CASR# 95-47-6), p-xylene (CASR# 106-42-3), since their molecular formula is the same they are called isomers. Their chemical structures are slightly different. Since they are often sold and used as 'mixed isomers', unless a particular isomer is specifically mentioned the information given will be discussing a mixture of the three isomers. Xylenes are flammable liquids and fire hazards. Xylenes are moderately soluble in water.
Further information
The National Pollutant Inventory (NPI) holds data for all sources of Xylenes (individual or mixed isomers) in Australia.
Health effects
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.
Entering the 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.
Exposure
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.
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).
Environmental effects
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.
Entering the environment
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).
Where it ends up
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 guidelines
No national guidelines.
Sources of emissions
Industry 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 industry sources included in diffuse 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.
Transport sources
Motor vehicles give off emissions to the air.
Consumer products
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.
References
Sources used in preparing this information
- Agency for Toxic Substances and Disease Registry (1990), Public Health Statement Xylene (accessed, May, 1999)
- Agency for Toxic Substances and Disease Registry (September,1996), ToxFAQS Xylene (accessed, May, 1999)
- CalEPA Air Resources Board Toxic Air Contaminant Summary Xylenes (Isomers and Mixture) (accessed, May, 1999)
- ChemFinder WebServer Project (1995), Xylenes (accessed, May, 1999)
- Environmental Defense Fund (1998), Xylene (mixed isomers): The Chemical Scorecard: (accessed, May, 1999)
- Environmental Health Center, a division of the National Safety Council, Environment Writer – Chemical Backgrounders Xylenes [(C6H4(CH3)2] (March, 1999) (accessed, May, 1999)
- National Environment Protection Council (1998a), National Environment Protection Measure for the National Pollutant Inventory (accessed, May, 1999)
- National Health and Medical Research Council (NHMRC) and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (1996) Australian Drinking Water Guidelines.
- New Jersey Department of Health and Senior Services (1995), Hazardous Substance Fact Sheet, Xylenes, PO Box 368, Trenton, NJ.
- New Jersey Department of Health, Right to Know Program (1986), TRIFacts, Xylenes (accessed, May, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- University of California, Davis; School of Veterinary Medicine, Vermont SIRI MSDS Archive Site: Xylene, technical (accessed, May, 1999)
- US Environmental Protection Agency and the Office of Air Quality Planning and Standards (May, 1998), Unified Air Toxics Website, Xylenes (accessed, May, 1999)
- US Environmental Protection Agency and the Office of Water, Office of Ground Water and Drinking Water, Consumer Factsheet on: Xylenes (accessed, May, 1999)
- Worksafe Australia (1996), Exposure Standard xylene (o-, m-, p-isomers) (accessed, May, 1999)
- Worksafe Australia (1996), Hazardous Substance Xylene (mixed isomers) (accessed, May, 1999)