A mortality study of oil refinery and petrochemical employees.

Results from a prospective mortality surveillance of 3803 refinery and petrochemical workers at a Shell Oil Company facility in Louisiana are presented. This report includes employees who worked more than 6 months before January 1, 1994 and pensioners who were alive as of January 1, 1973. Vital status was ascertained through 1993. Regardless of the comparison population used to calculate expected numbers (United States, Louisiana, or the surrounding tri-parish area), significantly fewer deaths were observed for all causes combined, all malignant neoplasms, heart disease, nonmalignant respiratory disease, and cirrhosis of the liver among male employees after 10 or more years' latency. With the United States as comparison, the all causes combined standardized mortality ratio (SMR) was 0.72 (95% confidence interval [CI] = 0.65 to 0.79), and the SMR for all cancer was 0.75 (95% CI = 0.61 to 0.92). The brain cancer rate for this group was nonsignificantly increased, with five observed deaths and three expected deaths, whereas mortality from leukemia was consistently lower than expected. The overall favorable mortality experienced by employees at this refinery and chemical plant is probably a result of a combination of factors, such as the healthy worker effect, relatively low risks related to the workplace, and the beneficial effects of continuing employment.

Illness absence at an oil refinery and petrochemical plant.

Results from a prospective illness-absence surveillance of refinery and petrochemical workers from 1986 through 1994 are presented. Illness absence data for this study were extracted from the morbidity section of the Shell Oil Company's Health Surveillance System, which includes records of all illness absences in excess of 5 days. The majority of employees (59%) had no illness absence during the 9-year period studied. The 13% of the population who had three or more absences accounted for 63% of the total illness absence episodes and 62% of the total work days lost. Frequency rate and duration of absence increased with increasing age. The increased illness absence was associated with the presence of known health risk factors, such as smoking, elevated blood pressure, high cholesterol, and obesity. For example, obese women had a twofold increased illness absence rate compared with nonobese women and the rate for male smokers doubled that of nonsmoking men. These health risk factors are also more common among employees with three or more absences than those with fewer or no absences. The goal of this analysis is to quantify the impact of illness absence to develop disease prevention strategies to maximize good health in employees and to minimize both the frequency and duration of illness absence.