At the request of the Carboloy management of the General Electric Company a study has been undertaken to address the question of whether there is evidence for work related disease risk among Carboloy employees in the Warren, Michigan plant. Concern was originally raised over a possible lung and colon cancer risk. However since manufacturing processes in this plant include the use of tungsten carbide and cobalt as major ingredients, a review of the scientific literature regarding exposure risk to these materials was carried out. This review identified cardiovascular disease and non-malignant pulmonary disease as risks which might be associated with work in such an environment. In consideration of these potential disease risks a first order decision was made to undertake a mortality study with the following objective: 'To examine the cause-of-death experience of GE plant employees in Warren, MI. in order to determine if there is any cause-specific concern requiring further epidemiologic assessment.'