An updated mortality follow-up study of Florida phosphate industry workers

We have added 14 years of mortality follow-up to a previously studied cohort of 18,446 white and 4,546 nonwhite male workers in the Florida phosphate industry. Follow-up was performed for the years 1949-1992. Based on comparisons with national rates, lung cancer standardized mortality ratios (SMR) were slightly elevated among white (SMR = 1.19; 354 observed) and nonwhite males (SMR = 1.13; 105 observed). However, no lung cancer excesses were found relative to local county rates (SMR = 0.98 for whites, SMR = 0.94 for nonwhites). Based on internal analyses of lung cancer mortality, using Poisson regression modeling, there were no associations of lung cancer with cumulative exposures to total dust, silica, or acid mists. There were weak trends of lung cancer risk with alpha and gamma radiation among white males, but no associations with radiation in nonwhites. No relation was found between acid mist exposures and laryngeal cancer. We conclude that there have not been large excesses of lung cancer or other diseases related to workplace exposures in this cohort.