From Envirowiki

Benzene, or Benzanol, (different to benzine) is an organic chemical, with the chemical formula C₆H₆. there's a good explaination of the chemical properties of Benzene on Wikipedia.org. Benzine is a carcinogen.

[edit] uses and sources

Benzine is an industrial solvent and is involved in the production of some drugs, plastics, synthetic rubber, and dyes. It is used as an additive in petrol, but less so now that previously. It comes naturally in crude oil, or can be synthesised.

[edit] toxicity

Benzene as an additive in petrol has been regulated to a maximum of 1% in the US and in Europe.

it may have had something to do with the Toxic Oil Syndrome (WP) outbreak in spain