A study update of mortality in workers at a phosphate fertilizer production facility

Abstract

Objective: To evaluate the mortality experience among 3,199 workers employed 1951-1976 at a phosphate fertilizer production plant in central Florida with follow-up through 2011. Methods: Cause-specific standardized mortality ratios (SMRs) for the full cohort were calculated with the U.S. population as referent. Lung cancer and leukemia risks were further analyzed using conditional logistic regression. Results: The mortality due to all-causes (SMR=1.07, 95% confidence interval [CI] 1.02-1.13, observed deaths [n]=1,473), all-cancers (SMR=1.16, 95%CI 1.06-1.28, n=431), and a priori outcomes of interests including lung cancer (SMR=1.32, 95%CI=1.13-1.53, n=168) and leukemia (SMR=1.74, 95%CI=1.11-2.62, n=23) were statistically significantly elevated. Regression modeling on employment duration or estimated radiation scores did not show exposure-response relation with lung cancer or leukemia mortality. Conclusion: SMR results showed increased lung cancer and leukemia mortality in a full cohort of the phosphate fertilizer production facility. There was, however, no exposure-response relation observed among cases and matched controls.