The report is a survey and summary of the literature on butadiene and its oligomers. Major aspects of their biological effects, environmental exposure, chemistry, production and use, and regulations are reviewed and assessed. Butadiene is a reactive gas used primarily in the production of rubbers and resins; over 3 billion pounds are produced annually in the U.S. Among other reactions, it undergoes self-condensation to form cyclic oligomers, such as 4-vinylcyclohexene, 1,5,9-cyclododecatriene, and 1,5-cyclooctadiene. The latter is used primarily as a precursor to nylon; the other oligomers are less important commercially. Vinylcyclohexene, however, is a contaminant in butadiene. Limited monitoring data indicate that low levels of butadiene enter the environment during production, end-use, storage and transport; it has been identified as a minor constituent of urban air and gasoline. The high degree of chemical reactivity of butadiene precludes environmental persistence. In humans, exposure to butadiene vapor may result in lethargy and drowsiness, as well as irritation to the eyes and mucous membranes. There have been no reports in the U.S. or Western Europe of long-term effects of butadiene arising from occupational exposure. Poorly documented cases of gastrointestinal tract, and circulatory and nervous system disorders have been reported in Russian synthetic rubber workers; butadiene has been implicated as a causitive factor. Butadiene intoxication may cause narcosis in laboratory mammals; few adverse effects have been reported for chronic exposures. Few toxicity data are available for the oligomers.