Mortality from brain tumor and other causes in a cohort of petrochemical workers.

To evaluate a suspected excess of deaths due to brain tumor (BT) among petrochemical workers, a retrospective cohort mortality study was conducted among 7,595 men ever employed at a plant in Texas City, Texas, between 1941 and 1977. Among hourly employees, overall mortality was lower than expected from U.S. national rates [standardized mortality ratio (SMR) = 79]. However, 19 BT deaths (International Classification of Diseases, seventh revision, codes 193, 223, and 237) among hourly employees were observed as against 9.6 expected (SMR = 198), and with extension of the analysis to include BT deaths occurring in 1978 and 1979, 22 deaths were observed versus 10.7 expected (SMR = 206). Fifteen years or more after being hired, 19 of these workers died from BT versus 7.2 expected (SMR = 263), and the standardized mortality ratios increased with duration of employment to 377 for hourly workers who had worked over 20 years. Although nonoccupational etiologies cannot be dismissed, these data suggest an occupational etiology for certain BT deaths in petrochemical workers.

A progress report: the investigation of brain tumors at the Texas Division of Dow Chemical.

During the six-month period since this investigation was initiated, an increased risk of death due to brain tumor was linked with employment at the Texas Division of Dow Chemical by the results of a case-control study based on county death certificates. Specifically, the county-based case-control study yielded an odds ratio of 2.54 with a 90% confidence interval of the odds ratio extending from 1.23 to 6.80. Additional investigations were initiated which resulted in the ascertainment of 25 brain tumor deaths among former Dow employees. Of these cases, 84% were initially employed between 1940 and 1946 and 64% can be described as glioblastomas or astrocytomas grade III and IV. Detailed protocols have been developed for a sample-based cohort study and a series of in-plant case-control studies. The sample-based cohort study is nearing completion and the in-plant case-control studies are anticipated to begin in the near future. The study design serving as the framework of this investigation represents a modest departure from the traditional epidemiologic study designs. This sample-based approach was designed to circumvent or minimize the usual problems associated with the use of massive collections of data that have been partially automated, if at all. The anticipated benefits will be conservation of limited staff resources and a reduction of the time necessary to complete a large-scale epidemiologic investigation.

Increased incidence of choroidal malignant melanoma occurring in a single population of chemical workers.

In five patients with choroidal melanoma occurring among present or former workers of the duPont Belle, West Virginia, plant the involved eye was enucleated and histopathologic confirmation of the diagnosis was made. This represents a statistically significantly greater than expected occurrence of choroidal melanomas in the white male study population.

A cross-sectional medical and industrial hygiene survey of workers exposed to carbon disulfide.

In 1979, the National Institute for Occupational Safety and Health (NIOSH) conducted a cross-sectional medical and industrial hygiene survey of workers exposed to carbon disulfide in the manufacture of rayon staple. The purpose of the study was to define dose-response relationships at levels near the existing United States standard of 20 ppm. The plant chosen has been historically well controlled, with levels between 10 and 30 ppm for most of its history. Medical tests were designed to examine effects on the central and peripheral nervous systems, on the cardiovascular system (including the retinal vessels), on carbohydrate, trace mineral, and lipid metabolism, on testicular function, and on thyroid function. This paper describes the plant, the exposed and reference populations, and the tests used to determine the health effects of carbon disulfide. The data are still being analyzed, but preliminary evidence suggests that carbon disulfide exposure at levels below the present standard of 20 ppm is associated with adverse effects. On the basis of the analysis completed to date the safety of the standard of 1 ppm recommended by NIOSH does not appear to be established.

Brain cancer in petrochemical workers: a case series report.

Eighteen primary brain cancer deaths among male workers at one Texas petrochemical plant from 1965-1980 are reported. Federal officials from OSHA and NIOSH are performing with company cooperation an historical prospective cohort mortality study, a case-control study, and neuropathological case confirmation. Average age at death was 53 (range 30-66). Median employment was 21 years and median latency was 24 years. 15/18 tumors were glioblastoma multiforme, an unusual histologic distribution. A preliminary estimate reveals a plant-wide excess brain cancer risk twice expected among 6,800 white males at the plant since 1941. Brain cancer mortality rates in surrounding counties are in the median range for US counties from 1950-1969. Ten recognized or suspected carcinogens are present in quantities greater than 10(6) lbs/yr. To date no common chemical exposures or work assignments have been identified among the cases. Data on 26 experimental brain carcinogens and relevant epidemiological studies are provided.