A total of 264 workers participated in a cross-sectional study concerning the toxicity of hydrocarbons. The clinical examination shows an increased prevalence of smell and/or taste disturbances in the heavily exposed group. These symptoms appear to be generally transitory and reversible. They seem to be due to concentration peaks rather than to a long exposure duration. They are associated with acute depressor effects and not with symptoms which could belong to a hydrocarbon-induced chronic toxic encephalopathy.