Results are reported from a nested case-control study of 60 esophageal cancer deaths among 46,384 hourly employees who worked in automobile manufacturing. Workers were exposed to metalworking fluids (MWF) in machining and grinding operations. Using incidence-density sampling, controls were selected with a sampling ratio of 20:1 from among coworkers at risk at the age of death of the case, matched on year of birth, race, gender, and plant. Conditional logistic regression was used to evaluate the risk associated with cumulative exposure to each of three types of MWF (straight, soluble, and synthetic MWF), as well as with years of exposure to selected additives and components, including ethanolamine, sulfur, biocides, and a variety of metals. Esophageal cancer was found to be significantly associated with exposure to both soluble and synthetic MWF in grinding operations. These associations were observed for both cumulative exposure and duration of exposure, although linear trends were present only for duration. For years of exposure to grinding with solubles, the odds ratio (OR) reached 5.3 (95% CI: 1.6-17.1) in the category of subjects exposed more than 12 years. When cumulative exposure rather than duration was considered, the OR rose to 6.6 (95% CI: 2.4-18.1) in the middle category of exposure and then fell to 2.5. The number of workers grinding with synthetics permitted a dichotomous exposure variable. The OR for those with any cumulative exposure to grinding with synthetics was 3.8 (95% CI: 1.1-13.2). Elevated risk was also identified in association with two agents commonly added to both synthetic and soluble fluids, ethanolamines and biocides. For any exposure to ethanolamines, the OR was 4.7 (95% CI: 1.3-17.2); for biocides the OR was 3.7 (95% CI: 0.817.6). However, since the same subjects were exposed to grinding with synthetics, biocides, and ethanolamines, it was not possible to separate out the specific risks associated with these components. In the U.S. alone, an estimated 3.8 million workers are potentially exposed to metalworking fluids.
Monitoring-systems; Air-quality-measurement; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Pulmonary-system-disorders; Materials-handling; Medical-surveys; Metal-compounds; Metal-dusts; Metal-fumes; Metal-industry; Metal-industry-workers; Metal-workers; Metallic-dusts; Metallic-fumes; Metallic-poisoning; Metalworking; Metalworking-fluids; Metalworking-industry; Risk-factors; Bactericides; Biochemical-analysis; Biocides; Biohazards; Biological-effects; Biological-monitoring; Time-weighted-average-exposure; Statistical-analysis
P Sullivan, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Division of Respiratory Disease Studies, 1095 Willowdale Road, Morgantown, WV 26505