This document is a review of the scientific literature on the biological and environmental effects of fluoride. Included in the review are a general summary and a comprehensive discussion of the following topics as related to fluoride and specific fluorine-containing compounds: physical and chemical properties; occurrence; synthesis and use; analytical methodology; biological aspects in microorganisms, plants, wild and domestic animals, and humans; and distribution, mobility, and persistence in the environment. The document also contains an evaluation of potential hazards resulting from fluoride contamination of the environment and suggests current research needs. More than 1000 references are cited.