Benzene is a light colourless liquid, with typical odour, slightly soluble in water. It is mainly used as a raw material in chemical industry. It is discarded in atmosphere with the emissions from the vehicles and through evaporation when working with petrol (at filling-stations and refineries).

Impact on human health
Benzene is absorbed in the organism when inhaled. Penetration through the skin is very small. In the organism major part of it undergoes metabolism to form phenol. About 30 % is eliminated unaltered through the exhaled air. It causes tachycardia, headache and influences the immune system.
Prolonged exposure to toxic levels of benzene damages the bone marrow and leads to pancitopenia.
Anemia, leucopenia and thrombocytopenia represent early toxicity manifestations. In the case of severe intoxications aplastic anemia develops. Benzene is known to be group 1 carcinogenic substance. Many cases of myeloblastic or erythroblastic leukemia are recorded resulting from professional exposure.
Information about the carcinogenic effect of benzene is collected mainly for professional exposure. Long-term exposure to high concentrations should be avoided.
The leukemia morbidity risk in the case of life-long exposure to 1 µg/m3 benzene is determined to be 4 – 10 – 6. No harmless concentration exists.

Our legislation sets the LV for benzene content in the atmospheric air as follows (Regulation No. 1, State Gazette, issue 14/16.01.2004). Regulation No1 reports p. 17 from Annex No1 of Regulation No. 14, State Gazette No. 88/1997, amended, SG No. 8/2002). - average annual LV (for 1 year exposure) - 5 µg/m3.