Nitrobenzene is a colorless to pale yellow oily liquid with an odor resembling that of bitter almonds or shoe polish. More than 95% of nitrobenzene produced is used in the production of aniline, a major chemical intermediate that is used in manufacture of polyurethane. Nitrobenzene is also used as a solvent in petroleum refining, as a solvent in the manufacture of cellulose ethers and acetates and as an intermediate to produce other organic compounds, including acetaminophen. This book evaluates the risks to human health and the environment posed by nitrobenzene. Nitrobenzene is toxic to humans by inhalational, dermal and oral exposure. The main systemic effect associated with human exposure to nitrobenzene is methaemoglobinaemia. Exposure to general population to nitrobenzene from air or drinking-water is likely to be very low. Although no no-observed-adverse-effect level (NOAEL) could be derived from any of the toxicological studies, there is a seemingly low risk for non-neoplastic effects. If exposure values are low enough to avoid non-neoplastic effects, it is expected that carcinogenic effects will not occur.