An update on mortality among workers at a 1,3-butadiene facility--preliminary results.

This is a cohort study of 2582 male workers employed at least 6 months between 1943 and 1979 at a 1,3-butadiene manufacturing facility. An earlier report on mortality through 1979 found a statistically significant deficit for all causes of death and lower than expected mortality for most of the leading causes of death. However, there was a statistically significant excess of deaths from lymphosarcoma. This report is a preliminary update of cohort information through 1985 and also a reanalysis of mortality. The all-causes standardized mortality ratio is 84 and that for all cancers is 80. These are statistically significant deficits; significant deficits were also seen for all cancer of the digestive system and all external causes of death. One additional death from lymphosarcoma was observed during the extended follow-up period giving a statistically significant standardized mortality ratio (SMR) of 229. The increase was concentrated in those employed less than 10 years and in those first employed before 1946. No increase was seen overall for leukemia (SMR = 102).

Mortality update of butadiene production workers.

This is a further update of a cohort mortality study of 2795 male workers employed at least 6 months between 1942 and 1994 at a 1,3-butadiene facility. Earlier reports on this cohort found a statistically significant deficit for all causes of death and lower than expected mortality for most leading causes of death. Prior reports noted an excess of deaths from lymphosarcoma primarily in those employed less than 10 years, first employed before 1946, and employed in jobs with the potential for daily exposure to butadiene (BD). There was a nonsignificant elevation for leukemia in persons potentially exposed to BD on an intermittent basis. The purpose of this update was to examine the patterns of mortality with four additional years of follow-up. Persons who had become eligible since the cohort was last updated through 1990 were also added. A total of 1222 deaths were identified, and death certificates were obtained for all but 20 of the deaths (1.6%). The standardized mortality ratio (SMR) for all causes of death is 88 (95% confidence interval (CI) = 83-93), and for all cancer, the SMR is 92 (95% CI = 82-104). There were 42 deaths from lymphohematopoietic cancers (LHC) with 28.6 expected (SMR = 147, 95% CI = 106-198), 9 observed vs. 4.7 expected deaths for lymphosarcoma (SMR = 191, 95% CI = 87-364), 13 observed vs. 11.5 expected deaths for leukemia (SMR = 113, 95% CI = 60-193), and 15 observed vs. 9.9 expected deaths from cancer of other lymphatic tissue (SMR = 152, 95% CI = 85-250). Subcohort analyses showed that the elevated risk of all LHC and its subcategories was restricted to persons who were first employed before 1950. As an adjunct to the SMR analyses, modeling was done using a qualitative cumulative exposure score as a time-dependent explanatory variable for, (1) all LHC (ICD 200-209); (2) lymphosarcoma (ICD 200); (3) lymphosarcoma and other lymphoma (ICD 200, 202); (4) multiple myeloma (ICD 203); and (5) leukemia (ICD 204-207). The cumulative exposure score was not significantly associated with any of these cancers. Cancer risk was found to increase with age for all of the LHC groups analyzed, except for lymphosarcoma. Similarly, cancer risk was found to increase with age-at-hire for all of the LHC groups except for multiple myeloma.

A cohort mortality study among workers at a 1,3 butadiene facility.

This is a cohort mortality study of 2800 male workers employed at least 6 months between 1943 and 1996 at a 1,3-butadiene monomer production facility. Earlier analyses of mortality for this cohort found statistically significant deficits for the 'all causes of death' category, and a lower than expected mortality for most leading causes of death. Past analyses also showed a significant elevation for deaths from cancers of the lymphohematopoietic system that was mainly due to an increase in deaths from lymphosarcoma. The purpose of this update was to examine the patterns of mortality through the end of 1999, for five additional years of follow-up. Persons who had become eligible between the last cohort update and April 1996 were added. Cohort membership was closed after April 1996 due to the sale of the facility. A total of 1422 deaths through December 1999 were identified, giving over 200 more deaths than in the last report on this aging cohort. The standardized mortality ratio (SMR) for all causes of death was 89 [95% confidence interval (95% CI) =84-94], which is statistically significantly low, and that for all malignant neoplasms was 90 (95% CI=81-101). The SMR for all lymphohematopoietic cancers (LHC) was 141 (95% CI=105-186) and is statistically significant. The SMR for leukemia was 129 (95% CI=77-204) and for non-Hodgkin's lymphoma (NHL), 148 (95% CI=89-231). The LHC elevations again were found only in workers first employed before 1950 and, in the group with the highest potential for exposure to butadiene, the elevations were highest in the short-term workers. Survival analyses were performed for all LHC [International Classification of Diseases (ICD) codes 200-209], NHL (ICD codes 200, 202), and leukemia (ICD codes 204-207) using an estimate of cumulative butadiene exposure as a time-dependent explanatory variable defined as a combination of job exposure class, calendar time, and length of time in job. The relative risks for the above causes of death were essentially 1.0, suggesting that there was no increase in risk with increasing butadiene exposure.

A framework for addressing health issues in or near a manufacturing facility.

Clustering of health events in or around industrial facilities sometimes leads to worker and community concerns that plant management or local health professionals must address. We provide an eight-step process to deal with these concerns systematically. We emphasize the use of good scientific practices with managerial oversight for effective worker and community communication. This process is directed to plant management and the local health professional and emphasizes the practical aspects of the investigation.

Texaco mortality study: III. A cohort study of producing and pipeline workers.

While there have been numerous epidemiology studies of refinery workers, no studies have been done on producing and pipeline workers. This is a retrospective follow-up study of all persons who were employed for at least 6 months at a Texaco producing or pipeline location and who worked at some time during the period 1946-1980. Of the 11,098 white men in the cohort, 8,964 were alive, 1,886 were known to be dead, and the vital status of the remaining 248 as of December 31, 1980 was unknown. The standardized mortality ratio (SMR) of 63 for all causes was significantly low, on the basis of 2,976 expected deaths. Statistically significant deficits also were seen for all major causes of death. Mortality patterns were also examined for the major job categories in these departments. Similar patterns of mortality were seen, although there was a significant excess of thyroid cancer in those employed as pumper-gaugers. However, it was based on only four cases.

Texaco Mortality Study: II. Patterns of mortality among white males by specific job groups.

While an earlier report on the Texaco Mortality Study cohort showed no statistically significant elevations for any cause of death for the white males, it did not preclude any excess risk of mortality within subgroups of workers. In this study, an employee's complete job history was used to determine his work categories, and patterns of mortality were examined for the more common job categories. All of the job categories examined showed deficits for mortality overall, and the patterns seen were similar to those for the entire cohort. Significant elevations were seen in pancreas cancer mortality for office and managerial people and in leukemia mortality for pipefitters and boilermakers. Other elevations of particular interest based on five or more deaths were brain cancer for laboratory workers and benign neoplasms in pipefitters and boilermakers. These associations were examined by latency and years worked, and no consistently positive associations were seen. It was not possible to take into account calendar time of exposure in this type of analysis, nor could any specific chemicals or levels of exposure be associated with the job categories where the standardized mortality ratios were elevated.

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

OBJECTIVE: To update information on workers in the petroleum industry engaged in the production of crude oil to determine whether the patterns of mortality have changed with 14 additional years of follow up. METHODS: All workers were employed at company production and pipeline locations sometime during 1946-94. The cohort now consists of 24 124 employees with an average of 22 years of follow up. RESULTS: The overall mortality, and most cause specific mortalities were lower than or similar to those for the general United States population. For white men (81% of the cohort), there were 4361 observed deaths and 5945 expected, 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, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the prostate, cancer of the brain and central nervous system, and cancer of other lymphatic tissue. For benign and unspecified 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 employed in production and pipeline jobs for >30 years. Overall mortality patterns for non-white men and women were similar to those for white men. Mortality patterns for white men were also examined by duration of employment, time 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.

Cancer mortality among workers at a butadiene production facility.

A cohort study was carried out of mortality among 2749 male workers who had been employed for at least six months between 1943 and 1990 at a 1,3-butadiene production facility. Most of the members of the cohort were covered in two earlier studies, both of which found a statistically significant deficit for all causes of death and lower than expected mortality from most of the main causes of death. Both also found a statistically significant excess risk for lymphosarcoma, which was concentrated in workers who had been employed for fewer than 10 years, had first been employed before 1946 and had been employed in jobs with routine potential exposure. The purpose of the study reported here was to examine the patterns of mortality after addition of five years of follow-up, new eligible cohort members and complete information on work histories. We were able to obtain information on the vital status of all but 1.4% of the cohort: 1051 deaths had occurred between 1943 and 1990. Death certificates were obtained for all but 15 of the deceased men (1.4%). The standardized mortality ratio (SMR) for all causes of death is 88, and this low figure is statistically significant; the SMR for all cancers, 87, is not statistically significant. The SMR for all lymphohaematopoietic cancers is 143 (95% confidence interval, 100-200). The SMR for leukaemia is 112 (11 deaths), that for lymphosarcoma, 209 (nine deaths), that for other lymphomas, 126 (10 deaths) and that for Hodgkin's disease, 175 (four deaths). None of the latter SMRs is statistically significant.

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 study to determine if the patterns of mortality have changed with 16 additional years of follow up. SUBJECTS AND METHODS: All workers were employed for > or = 5 years at company refineries, petrochemical plants, and research laboratories from 1947-93. The cohort now consists of 28,480 employees with an average of > or = 20 years of follow up. RESULTS: The overall mortality, and most cause specific mortalities were lower 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 ratio (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, stroke, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the pancreas, cancer of the brain and central 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 to those for white men. Mortality patterns for white men were also examined by duration of employment, time first employed, location, and by job and process unit. There were significantly increased SMRs for brain cancer for those people employed as laboratory workers and on units with motor oil and for cancer of other lymphatic tissue for people employed on the fluid catalytic cracking unit. CONCLUSIONS: The results of the updated study showed a favourable mortality experience for employees in the Texaco mortality study compared with the United States population. There were a few increases found consistently including, 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.

Update of the Texaco mortality study 1947-93: Part II. Analyses of specific causes of death for white men employed in refining, research, and petrochemicals.

OBJECTIVE: To examine patterns of mortality for specific causes of death with increases in the Texaco mortality study to determine if the patterns are related to employment in the petroleum industry. METHODS: Mortality patterns by duration of employment in various job groups were examined for mesothelioma, non-Hodgkin's lymphoma, multiple myeloma, cell type specific leukaemia, and brain tumours. RESULTS: Mortality from mesothelioma was examined for the total cohort and for two maintenance groups with the greatest potential for exposure to asbestos. The insulator group had a standardised mortality ratio (SMR) of 3029, and a larger group consisting of insulators, carpenters, labourers, electricians, pipefitters, boiler-makers, and welders had an SMR of 411. The mortalities from mesothelioma increased with increasing duration of employment. Mortality was lower for those first employed after 1950. An analysis of all brain tumours for the total cohort and some job and unit subgroups resulted in an SMR of 178 for those employed on the units related to motor oil and 166 for those employed as laboratory workers. Mortality from brain tumours in both of these job groups was higher for those employed > or = 5 years in the group. An analysis of non-Hodgkin's lymphoma showed no consistent patterns among the various employment groups. Mortality from multiple myeloma was non-significantly increased among people employed on the crude (SMR = 155) and fluid catalytic cracking units (SMR = 198). Leukaemia mortality was not increased for the total cohort, and a cell type analysis of leukaemia mortality for the total cohort showed no significant increases for the major cell types. However, there were significant increases for acute unspecified leukaemia (SMR = 276) and leukaemia of unknown cell type (SMR = 231). CONCLUSIONS: Analyses of specific causes of death by duration of employment in various job and process units did not show any patterns which suggest that, other than for mesothelioma, any of these increases in mortalities were likely to have resulted from workplace exposures or from employment at one of the places included in the Texaco mortality study.

Texaco mortality study. I. Mortality among refinery, petrochemical, and research workers.

The Texaco mortality study is a retrospective follow-up study of all persons who were employed for at least five years in a refining, petrochemical, or research facility and who worked at some time during the period 1947 through 1977. Of the 19,077 white men in the cohort, 14,609 were alive, 4,024 were known to be dead, and the vital status of the remaining 444 was unknown as of Dec. 31, 1977. The standardized mortality ratio (SMR) of 75 for all causes was significantly low, on the basis of 5,332 expected deaths. Statistically significant deficits also were seen for all major causes of death and for cancer of many sites, including lung, stomach, bladder, and colon. The SMR was greater than 100 for six causes of death: pancreas cancer, brain cancer, leukemia, Hodgkin's disease, other lymphatic cancer, and benign neoplasms. However, none of these increases was statistically significant, and all SMRs except that for benign neoplasms (SMR = 148) were under 119.

Mortality among ethylene oxide workers.

Because of reports linking an increased risk of leukemia with exposure to ethylene oxide, a mortality study of workers with potential exposure to ethylene oxide at the Texaco Chemical Company Plant in Port Neches, Tex., was undertaken. A total of 767 males with potential exposure to ethylene oxide were identified. Forty-six deaths occurred in this cohort with 80 expected (standardized mortality ratio; SMR = 58). No deaths from leukemia were seen, nor were there any statistically significant excesses from any specific causes of death.