The attached paper, 'Epidemiologic Study of Workers exposed to Acryionitrile', is the final report of a study on which a preliminary report was issued in May 1977. Since then, the status of those persons lost to follow up has been determined and their cancer experience included in the data evaluations. This study concludes that these findings, coupled with results from tests in laboratory animals, raise the serious suspicion that acrylonitrile may be a human carcinogen. However, further studies are needed to confirm or refute the suggested increased risks which are seen in certain subgroups of this cohort. This paper is being submitted for publication in the Journal of Occupational Medicine and should not be reproduced in its entirety in any other publication.