Acetaldehyde is a widespread, naturally occurring, colorless and flammable liquid with a suffocating smell. Acetaldehyde is found in various plants, ripe fruits, vegetables, cigarette smoke, gasoline and diesel exhaust. This substance is widely used in the manufacture of acetic acid, perfumes, dyes and drugs, as a flavoring agent and as an intermediate in the metabolism of alcohol. Acute exposure to its vapors results in irritation of the eyes, skin, and respiratory tract. Acetaldehyde is reasonably anticipated to be a human carcinogen.