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.

Mortality study of two overlapping cohorts of photographic film base manufacturing employees exposed to methylene chloride.

The mortality experience of two overlapping cohorts of employees engaged in the manufacture of photographic film support was evaluated to assess the potential chronic health effects of methylene chloride exposure. In the first analysis, we examined causes of death among 1311 men initially employed between 1946 (when the solvent was first used) and 1970; in the second, we updated mortality in a 1964 to 1970 employed cohort of 1013 men. Follow-up was through 1994. The mean exposure among members of the 1946 to 1970 cohort was 39 ppm (8-hour time-weighted average) for 17 years, and the median length of follow-up from first exposure was 34 years. Members of the 1964 to 1970 cohort received an average exposure of 26 ppm for 24 years; median time from first exposure was 35 years. Compared with general population vital statistics, mortality in both cohorts was below expectation for all causes of death, ischemic heart disease, and cancer, including such sites as the lung and liver, which were target organs identified in animal toxicology studies. No statistically significant increases were observed for any cause of death. The combined results of this study and three others in the photographic film and textile fibers industries (approximately 7300 subjects) show that long-term exposure to methylene chloride does not increase the risk of death from any cause including specific diagnoses that have been associated with this widely used solvent.

Quantifying uncertainty in a risk assessment using human data.

A call for risk assessment approaches that better characterize and quantify uncertainty has been made by the scientific and regulatory community. This paper responds to that call by demonstrating a distributional approach that draws upon human data to derive potency estimates and to identify and quantify important sources of uncertainty. The approach is rooted in the science of decision analysis and employs an influence diagram, a decision tree, probabilistic weights, and a distribution of point estimates of carcinogenic potency. Its results estimate the likelihood of different carcinogenic risks (potencies) for a chemical under a specific scenario. For this exercise, human data on formaldehyde were employed to demonstrate the approach. Sensitivity analyses were performed to determine the relative impact of specific levels and alternatives on the potency distribution. The resulting potency estimates are compared with the results of an exercise using animal data on formaldehyde. The paper demonstrates that distributional risk assessment is readily adapted to situations in which epidemiologic data serve as the basis for potency estimates. Strengths and weaknesses of the distributional approach are discussed. Areas for further application and research are recommended.

Metabolic risk factors for cardiovascular disease in a working population: a retrospective cohort study.

Risk factors for cardiovascular disease (CVD) appear to cluster in individuals, possibly because of a single, underlying metabolic disorder. We describe the prevalence of metabolic risk factors for CVD in a young working population and the tendency for individuals with some risk factors to acquire additional factors. This was a retrospective three-year follow-up study of baseline CVD risk factors assessing (1) incidence of risk factors and (2) fatal CVD. The study group consisted of 9,747 Eastman Kodak employees, who participated in a worksite-based cardiovascular screening program in Rochester, New York, which included a medical history, physical examination, and laboratory evaluation. Abnormal metabolic risk factors were defined as (1) an abnormal glucose value (fasting blood sugar greater than 115 mg/dl); (2) abnormal lipids (high-density lipoprotein cholesterol under 35 mg/dl in men or under 45 mg/dl in women; or low-density lipoproteins of 160 or greater; or triglycerides greater than 250 mg/dl), and (3) hypertension (blood pressure systolic above 160 mmHg; or diastolic above 90 mmHg). Subjects were classified as having none, one, two, or all three risk factors. Prevalence of single risk factors were: hypertension 9.8%, abnormal lipids 22.6%, and abnormal glucose 1.5%. Combinations of two risk factors were greater than expected by chance (p < 0.01). Individuals who started with one or more abnormal values tended to have an increased risk of developing others. The highest relative risk (RR) was for those with hypertension and a later diagnosis of abnormal glucose (RR 2.0; 95% CI = 0.87, 4.58). Seven employees of 4,263 with at least one risk factor died of CVD, compared with one of 5,484 employees with no factors (RR 9.0, 95% CI = 1.1, 73.2). In conclusion, this study suggests that young working individuals with CVD risk factors may continue to acquire additional factors. This clustering could be an indication of an underlying metabolic disorder and identify individuals at risk for negative CVD sequelae.

Mortality study of employees engaged in the manufacture and use of hydroquinone.

Mortality in a 1942-1990 cohort of 858 men and 21 women employed in the manufacture and use of hydroquinone was evaluated through 1991. Average exposure concentrations, 1949-1990, ranged from 0.1 to 6.0 mg/m3 for hydroquinone dust and from less than 0.1 to 0.3 for quinone vapor (estimated 8-h time-weighted averages). Compared with general population and occupational referents, there were statistically significant deficits in total mortality and deaths due to cancer. No significant excesses were observed for such hypothesized causes as kidney cancer [2 observed vs 1.3 expected (both control groups), P approximately 0.39], liver cancer (0 vs 0.8, 1.3), and leukemia (0 vs 2.3, 2.7). Dose-response analyses of selected causes of death, including renal carcinoma, demonstrated no statistically significant heterogeneities or linear trends according to estimated career hydroquinone exposure (mg/m3-years) or time from first exposure.

Absence of adverse mortality effects in workers exposed to methylene chloride: an update.

Mortality findings in a 1964 to 1970 cohort of 1013 hourly-wage men exposed to methylene chloride were substantially unchanged after 4 additional years of observation through 1988. Mean exposure was 26 ppm (8-hour time-weighted average) for 23 years; median follow-up from first exposure was 33 years. A comparison with death rates in both general population and industrial referents showed nonsignificant deficits in observed-expected ratios for such hypothesized causes as lung and liver cancer and ischemic heart disease. Overall mortality from 1964 to 1988 (n = 238) was significantly decreased v both referent groups. The study had 90% power to detect relative risks of 1.7 and 1.3 for lung cancer and ischemic heart disease, respectively; power was inadequate for hepatic cancer. No pancreatic cancer deaths occurred since the 1984 follow-up; eight have been observed v 4.2 expected (P = .13). An analysis of dose response for selected causes of death demonstrated no statistically significant trend according to either career methylene chloride exposure or latency. Similar results were observed when the data were analyzed using Poisson regression modeling.

Outbreak of hypersensitivity pneumonitis in an industrial setting.

Symptoms consistent with hypersensitivity pneumonitis developed in several workers in two multistory buildings in an industrial complex. A health questionnaire survey was conducted to determine the extent of the problem. Eighty-seven percent of the population of 1050 employees completed the health questionnaire. Serological testing identified 152 positive precipitin reactors to the fungus Aureobasidium pullulans; 115 reactors were symptomatic. The clinical and laboratory features at the time of the acute illness and during four years of follow-up are described. The agent, A pullulans, was identified as a contaminant of the heating-cooling ventilation units containing open waterspray chambers. Control was accomplished by replacement of the ventilation systems. A secondary source of antigen was found to be corrugated cardboard. Some sensitized employees required removal from work exposure to corrugated cardboard to prevent recurrent symptoms.

Methylene chloride mortality study: dose-response characterization and animal model comparison.

To assess the potential chronic health effects of methylene chloride, the mortality experience of a maturing 1964 to 1970 cohort of 1,013 hourly men was evaluated through 1984. On average, employees were exposed at a rate of 26 ppm (eight-hour time-weighted average) for 22 years; median latency was 30 years. Compared with the general population, no statistically significant excesses were observed for such hypothesized causes as lung cancer (14 observed v 21.0 expected), liver cancer (0 v 0.8), and ischemic heart disease (69 v 98.1); dose-response relationships based on career methylene chloride exposure and latency were not demonstrated. Among nonhypothesized causes, a significant deficit was reported for total deaths (176 v 253.2). None of the industrial referent comparisons achieved statistical significance. Sufficient power was available to detect relative risks of 1.6 for lung malignancy and 1.3 for ischemic heart disease. In contrast, there was inadequate power to identify meaningful risk levels for hepatic cancer. With 14 combined lung and liver cancer deaths observed v 36.3 predicted (P less than .0001), the mortality estimate projected from a mathematical model derived from an animal bioassay substantially overestimated cancer mortality for these sites. This inconsistency emphasizes the need to incorporate epidemiologic evidence in assessing the human health risks associated with long-term exposure to this widely used solvent.

Mortality study of men employed at a large chemical plant, 1972 through 1982.

The mortality experience of a cohort of approximately 9,000 traced men employed at a Tennessee chemical plant was examined between 1972 and 1982. Statistically significant total mortality deficits of 41% to 46% and 14%, respectively, were observed compared with general population and occupational controls. Cancer deaths were 22% (significant) below expectation based on state and national vital statistics, whereas comparison with an employed group showed no difference. Significantly low mortality differentials were also reported for other major causes, including diseases of the circulatory, respiratory, and digestive systems. Analysis of the data by length of employment, payroll status, and chemical production division demonstrated no unusual patterns. The cohort's favorable mortality experience may be attributed to such factors as employee selectivity, health maintenance, accessibility to medical care, and less cigarette smoking.

Mortality, cancer incidence, and sickness-absence in photographic processors: an epidemiologic study.

An epidemiologic investigation of a 1964 cohort of 478 photographic processors in nine Eastman Kodak Color Print and Processing (CP&P) laboratories in the continental United States was undertaken. Analysis of pre-1965 environmental data indicated that chemical exposures were within the standards applicable at the time. The results showed no significant excess mortality, sickness-absence or cancer incidence. The processing cohort's mortality experience after 16 years of follow-up compared favorably with that of two industrial control populations. The present study represents (to our knowledge) the first published occupational epidemiology investigation that specifically examines the health of workers engaged in large-scale commercial photofinishing operations.