Update of the Texaco mortality study 1947-93: part I. Analysis of overall patterns of mortality among refining, research, and petrochemical workers

Objective-To update information on the workers of the Texaco mortality stud y to determine if the patterns of mortality have changed with 16 additional years of follow up. Subjects and methods-Ah workers were employed for greater than or equal to 5 years at company refineries, petrochemical plants, and research laborator ies from 1947-93. The cohort now consists of 28 480 employees with an avera ge of greater than or equal to 20 years of follow up. Results-The overall mortality, and most cause specific mortalities were low er than or similar to those for the general population of the United States . For white men (86% of the cohort), there were 8873 observed deaths and 11 181 expected resulting in a significantly lower standardised mortality rat io (SMR) of 79. There were significant deficits for all the leading causes of death in the United States including all cancers, cancer of the lung, st roke, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the pancreas, cancer of the brain and ce ntral nervous system, leukaemia, and cancer of other lymphatic tissue. For cancer of the bone, the SMR was 162 (95% confidence interval (95% CI) 86 to 278), and for benign and unspecified neoplasms, it was 152 (95% CI 109 to 206). Overall mortality patterns for non-white men and women were similar t o those for white men. Mortality patterns for white men were also examined by duration of employment, time first employed, location, and by job and pr ocess unit. There were significantly increased SMRs for brain cancer for th ose people employed as laboratory workers and on units with motor oil and f or cancer of other lymphatic tissue for people employed on the fluid cataly tic cracking unit. Conclusions-The results of the updated study showed a favourable mortality experience for employees in the Texaco mortality study compared with the Un ited States population. There were a few increases found consistently inclu ding, but not limited to, brain cancer and cancer of other lymphatic tissue . These increases led to additional analyses that will be discussed in the accompanying paper.