SPRI Home About SPRI

Trimethylbenzene - all isomers

SPRI Emission Reporting Threshold
10.0 Kg/yr Pollutant Emissions to Air
Disclaimer
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Trimethylbenzene has three different structures. It is usually found as a mixture of these three structures. Under normal conditions, Trimethylbenzene is a clear, colourless liquid, which has a characteristic smell. It is flammable and will break down when heated, producing toxic fumes in the process. Trimethylbenzene boils at around 170 degrees celsius. It is only very slightly soluble in water, but will dissolve in organic (carbon-containing) solvents. Trimethylbenzene is one of a group of substances known as the volatile organic compounds (VOCs).
What is it used for?
The vast majority of Trimethylbenzene is added to petrol to enhance efficiency and performance. The rest is used in the chemical industry to produce chemicals for solvents, inks and printing materials, cleaning agents and pesticides.
Where does it come from?
Releases of Trimethylbenzene may occur from industry producing or using it. It might also be released during the storage of petrol and refuelling of vehicles and it is present in diesel exhaust fumes. Trimethylbenzene is found naturally in crude oil.
How might it affect the environment?
Trimethylbenzene is classed as toxic to aquatic organisms. However, levels sufficiently high to cause harm are relatively rare because most releases quickly evaporate into the atmosphere where it is broken down within a matter of hours. The small amounts that remain in soils or surface waters are broken down by biological and microbial processes. As a VOC, Trimethylbenzene may be involved in the formation of ground level ozone, which can damage crops and materials. It is not considered likely that Trimethylbenzene pollution has any effects on the global environment.
How might exposure to it affect human health?
Trimethylbenzene exposure occurs mainly in the occupational setting. Trimethylbenzene can enter the body either by inhalation of air containing trimethylbenzene, ingestion of contaminated food or water, or by dermal contact with trimethylbenzene. Inhalation of air containing trimethylbenzene can lead to irritation of the respiratory tract, sore throat, headache, wheezing, vomiting, anxiety, tension and may affect the blood. Ingestion of trimethylbenzene may lead to health effects similar to those for inhalation. Dermal contact with trimethylbenzene can irritate the skin. Eye contact can cause irritation. The International Agency for Research on Cancer has designated 1-Amino-2,4,5-trimethylbenzene and 2-Amino-1,3,5-trimethylbenzene as being not classifiable as to their carcinogenicity to humans. However, exposure to trimethylbenzene at normal background levels is unlikely to have any adverse effect on human health.
What steps are being taken to limit the potential impacts?
Releases of Trimethylbenzene are controlled through the UK Pollution, Prevention and Control (PPC) Regulations and the UK Surface Waters Regulations (SI 1997/2560). As a VOC, levels of Trimethylbenzene in air are also controlled through the UK National Air Quality Strategy. European Directives regulating levels of Trimethylbenzene include the European Solvents Directive (99/13/EC) and that which evaluates and controls the risks of substances known to be in the environment (793/93). The main international legislation regulating levels of VOCs such as Trimethylbenzene is the UN/ECE Convention on Long-Range Transboundary Air Pollution and the Basel Convention on the transboundary movement and disposal of hazardous wastes.