An epidemiologic study was made to describe demographic, occupational, and toxicologic characteristics of all deaths occurring at work in Allegheny County, Pennsylvania, from 1979 through 1982. County coroner's records were assessed for 212 identified deaths occurring at work among employed white males. Sudden natural deaths occurred in 68 percent and fatal workplace injuries in 32 percent. Age groups 16 to 24 years and 65 or more years had the highest fatal injury rates. The construction industry had the highest age adjusted fatal injury rate, 4.4 times as high as the overall rate for the county. Non road motor vehicles were the chief cause of fatal injuries (19 percent). In 25 percent of fatal workplace injuries, other workers were also injured or killed, the predominant cause being burns and explosions. Few fatal injuries were associated with raised blood alcohol or carboxyhemoglobin, and none with acute coronary events. Sudden natural deaths increased rapidly in incidence in the 45 to 64 year age group and were greatest in the 65 years or older group. Service occupations showed the highest sudden natural death at work incidence, after adjusting for age; 45 percent of these were in custodians and maintenance workers. Coronary problems were found in a great number of cases of sudden natural death. Few had elevated blood alcohol levels, but 11 percent had trace or elevated carboxyhemoglobin levels (most were trace levels). The authors conclude that coroners' records would be useful in future surveillance of sudden death at work because they identify more of these than do death certificates.