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