Benzene (C6H6)

CAS Number



  • aromatic hydrocarbon
  • colourless liquid with aromatic odour
  • flammable under normal conditions, chemically stable, moderately soluble in water
  • volatile, mainly in gas form (high vapour pressure)
  • part of the BTEX collective parameter (benzene, toluene, ethylbenzene, xylenes)

Main sources

  • motorised road transport (benzene)
  • combustion and heating (wood, gas and oil combustion processes)
  • petrol stations and storage tanks (evaporation of fuel and combustibles)
  • tobacco smoke

Thresholds for the reporting requirement of facilities in accordance with Annex 2 PRTRO

(Ordinance on the Register relating to Pollutant Release and the Transfer of Waste and of Pollutants in Waste Water)

  • Air               1,000 kg/year
  • Water          200 kg/year
  • Soil              200 kg/year


  • carcinogenic (leukemia)
  • acute effect on eyes, respiratory system and central nervous system in higher concentrations
  • no threshold has been found under which there is no threat to health

Status and changes

Benzene concentrations have declined continuously since the 1990s. From 2000 to 2010, benzene emissions were cut in half.

    Further information

    Last modification 04.07.2018

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