Toluene is a volatile liquid, slightly soluble in water. Its main sources are oil production, coke ovens and chemical substance (such as styrene) production. It is widely used as die, ink, glue solvent, in cosmetics and as fuel additive.
Toluene exposure is mainly through the air. Potable water and food are not essential sources of this pollutant.

Impact on human health
When inhaled from 40 % to 60 % of the toluene is absorbed. It may as well get absorbed through the skin. In the human body it is distributed in the fatty tissue, adrenal gland, kidneys, liver and brain.
It undergoes metabolic transformation to benzoic acid, which combines with glycine to form hypuric acid, which is excreted with urine. The toxic effects on man are studied based on professional exposure.
Toluene has the most significant effect on the central nervous system (CNS). Small concentrations cause fatigue, drowsiness, depression, headache and cold. Changes of the EEG (electroencephalogram) are witnessed. At higher concentrations eye irritation is witnessed. No data exists of carcinogenic effect of toluene on man. The olfaction threshold of toluene is 1 mg/m3.
Avoidance of long-term exposure to high concentrations is recommended. The lowest concentration at which impact on the CNS and mucous membrane irritation is witnessed is 332 mg/m3. The WHO recommends a safety LV of 50 mg/m3 for 24-hour exposure. As admissible exposure of the population in accordance with the olfaction threshold the WHO recommends a LV of 1 mg/m3 for a 30-minute exposure.

The following limit values for toluene content in the atmospheric air are set by our legislation Regulation No. 14 (State Gazette No. 88/1997, amended SG No. 46/1999, amended and supplemented, SG No. 8/2002): - maximum single dose LV (for 60 minute exposure) - 0,5 mg/m3;
- 24 hour average LV (for 24-hour exposure) - 0,25 mg/m3.