Update of a study of crude oil production workers 1946-94

Objective-To update information on workers in the petroleum industry engage d in the production of crude oil to determine whether the patterns of morta lity have changed with 11 additional years of follow up. Methods-All workers were employed at company production and pipeline locati ons sometime during 1946-94. The cohort now consists of 24 124 employees wi th an average of 22 years of follow up. Results-The overall mortality, and most cause specific mortalities were low er than or similar to those for the general United States population. For w hite men (81% of the cohort), there were 4361 observed deaths and 5945 expe cted, resulting in a significantly lower standardised mortality ratio (SMR) of 73. There were significant deficits for all the leading causes of death in the United States including all cancers, cancer of the lung, stroke, he art disease, respiratory disease, and accidents. Slightly increased mortali ty was found for cancer of the prostate, cancer of the brain and central ne rvous system, and cancer of other lymphatic tissue. For benign and unspecif ied neoplasms, the SMR was 152 (95% confidence interval (95% CI) 95 to 230) . There was a significant increase for acute myelogenous leukaemia that was restricted to people who were first employed before 1940 and who were empl oyed in production and pipeline jobs for >30 years. Overall mortality patte rns for non-white men and women were similar to those for white men. Mortal ity patterns for white men were also examined by duration of employment, ti me first employed, and by job group. Conclusions-The results of the updated study showed a favourable mortality experience for crude oil production workers compared with the United States population.