The majority of toluene is used as a component of petrol. It is also used in paints, lacquers, inks, adhesives, rubber, and cleaning agents. It is used to manufacture benzene, urethane raw materials, and other organic chemicals. It is used in the production of pharmaceuticals, dyes, and cosmetic nail products. It is used against roundworms and hookworms.
Substance name: Toluene (methylbenzene)
CASR number: 108-88-3
Molecular formula: C7H8
Synonyms: Toluol; phenyl methane; methylbenzol; methyl-benzene; monomethylbenzene
Toluene is a clear, colourless liquid with a sweet smell.
Melting Point: -95°C
Boiling Point: 110.6°C
Vapour Density: 3.13
Specific Gravity: 0.867 (at 20°C)
Toluene is non-corrosive, flammable and insoluble in water, but soluble in most organic solvents.
The National Pollutant Inventory (NPI) holds data for all sources of Toluene (methylbenzene) in Australia.
Short-term exposure to high levels of toluene results first in light-headedness and euphoria, followed by dizziness, sleepiness, unconsciousness, and in some cases death. When exposure is stopped prior to death the symptoms disappear. Long-term exposures at low levels have caused effects to the kidneys. Long-term exposures to high amounts of toluene by intentional abuse have been linked to permanent brain damage. Also reported are problems with speech, vision, and hearing, loss of muscle control, loss of memory and balance and reduced scores of psychological tests.
Entering the body
Toluene will enter the body if we breathe in contaminated air, breathe in tobacco smoke, or consume food or water that contains toluene. It can also be absorbed through the skin, if liquid toluene is in contact with the skin. Human exposure occurs mainly by breathing air containing toluene. Toluene usually leaves the body with in twelve hours.
Consumers are most likely to be exposed to toluene by smoking or using consumer products containing toluene (paints, varnish, nail polish, paint cleaners, stain removers, etc.) especially if there is not good ventilation. Because toluene is used in many consumer products, and found in tobacco smoke, short-term indoor concentrations may be elevated above the levels considered safe for workers. Workers in the industries that use or produce toluene are at risk of exposure. Consumers can also be exposed to toluene by exposure to air from production and processing facilities using toluene, and automotive exhaust. Sniffing glue or paint can also lead to high exposures.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for toluene through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 50 parts per million (191 mg/m3)
- Maximum short term exposure limit (STEL): 150 parts per million (574 mg/m3)
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
The Australian Drinking Water Guidelines include the following guidelines for acceptable water quality:
- Maximum of 0.8 milligrams per litre of water for health purposes
- Maximum of 0.025 milligrams per litre of water for aesthetic considerations
Toluene evaporates when exposed to air. It also evaporates from water. In the air it quickly is reacted into other chemicals, in the water and soil bacteria break it down. It has moderate acute (short-term) toxicity on aquatic life. Toluene has caused membrane damage to the leaves in plants. It has moderate chronic (long-term) toxicity to aquatic life. Chronic and acute effects on birds or land animals have not been determined. Toluene is expected to minimally bioaccumulate.
Entering the environment
Industrial emissions of toluene can produce elevated, concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere toluene is expected to be confined to the local area within which it is emitted. Toluene that makes its way into the ground, and does not evaporate, may move through the ground and enter groundwater (bore water), it is degraded in the water with in days.
Where it ends up
Toluene quickly evaporates to a gas if released as a liquid. It evaporates from both water and soil when exposed to air. It will break down in the air in a few days into other chemicals (benzaldehyde and cresol, which are harmful to humans). In the soil and water bacteria will break it down.
Australian Water Quality Guidelines for Fresh and Marine Waters: (ANZECC, 1992):
Maximum of 300 micrograms/L (i.e. 0.0003 g/L)
Sources of emissions
The primary sources of toluene are the industries that manufacture it or use it in production. Some of the industries that manufacture it or use it in production are oil refiners, chemical industry, rubber manufacturers, pharmaceutical industry, metal degreasing, printing, manufacturers of paints, varnishes and lacquers. These emissions mainly are to the air, but are also to the soil and water.
Diffuse sources, and industry sources included in diffuse emissions data
Other possible emitters of toluene are vapours and spilling of petrol, commercial and household painting and paint, varnish and lacquer removal, tobacco smoke, and consumer products containing toluene. These emissions are to the air unless there is a spill.
Natural sources of toluene include volcanoes, forest and bush fires and crude oil.
Some toluene is found in vehicle exhaust.
Adhesives, Auto polish and cleaners, floor polish, hard surface cleaners, paints, inks, paint cleaners, paint and varnish removers and thinners, coatings, particleboard, leather dressings, lubricating oils, fingernail enamels and removers, shoe polish and cleaners, solvent thinned products (exterior stains, primers, interior stains, clear finish), colouring pens and markers, wood office furniture, vinyl flooring.
Sources used in preparing this information
- Agency for Toxic Substances and Disease Registry (1989), Public Health Statement Toluene (accessed, May, 1999)
- Agency for Toxic Substances and Disease Registry (1997), ToxFAQS Toluene (accessed, May, 1999)
- Australian and New Zealand Environment and Conservation Council (ANZECC) (1992), Australian Water Quality Guidelines for Fresh and Marine Waters.
- CalEPA Air Resources Board Toxic Air Contaminant Summary Toluene (accessed, May, 1999)
- ChemFinder WebServer Project (1995), Toluene (accessed, May, 1999)
- Cornell University, Planning Design and Construction, MSDS, Toluene, ACS (accessed, May, 1999)
- Environmental Defense Fund (1998), Toluene: The Chemical Scorecard: (accessed, May, 1999)
- Environmental Health Center, a division of the National Safety Council, Environment Writer – Chemical Backgrounders Toluene (C6H5CH3) (July, 1997) (accessed, May, 1999)
- National Environment Protection Council (1998a), National Environment Protection Measure for the National Pollutant Inventory (accessed, May, 1999)
- New Jersey Department of Health, Right to Know Program (1986), TRIFacts Toluene (accessed, May, 1999)
- NTP Chemical Repository, Radian Corporation, Toluene (AUGUST 29, 1991) (accessed, May, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- US Environmental Protection Agency and the Office of Air Quality Planning and Standards (May, 1998), Chemical summary for Toluene (accessed, May, 1999)
- US Environmental Protection Agency and the Office of Air Quality Planning and Standards (May, 1998), Unified Air Toxics Website, Toluene (accessed, May, 1999)
- US Environmental Protection Agency and the Office of Water, Office of Ground Water and Drinking Water (January, 1998), Consumer Factsheet on: Toluene (accessed, May, 1999)
- US Environmental Protection Agency and the Office of Water, Office of Ground Water and Drinking Water (January, 1998), Technical Factsheet on: Toluene (accessed, May, 1999)
- Worksafe Australia (1996), Hazardous Substance Toluene (accessed, May, 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed March 2019.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018.