Mortality of lead workers.

The mortality of 7,032 men employed for one or more years in lead production facilities or battery plants was followed over a 23-year period, 1947 to 70. Lead absorption in many of these men was greatly in excess of currently accepted standards based upon urinary and blood lead concentrations available for a portion of the group. There were 1356 deaths reported; death certificates were obtained for 1267. The standardized mortality ratio (SMR) for all causes was 107 for smelter workers and 99 for battery plant workers. Deaths from neoplasms were in slight excess in smelters, but not significantly increased in battery plants. There were no excess deaths from kidney tumors. The SMR for cardiovascular-renal disease was 96 for smelter workers and 101 for battery plant workers, i.e. roughly the same as for the general population, but not as good as would be expected in a population that had been employed. There was definitely no excess in deaths from either stroke or hypertensive heart disease. However, deaths classified as "other hypertensive disease" and "unspecified nephritis or renal sclerosis" were higher than expected. The actual numbers of deaths in these last-named categories combined (41 where 19.5 were expected) represented about 3% of all certified deaths. The life expectancy of lead workers was calculated to be approximately the same as that of all U.S. males. Considering the high levels of exposure in this population of workers and the small deviations from expected mortality, one can be optimistic in predicting no detectable effect on the mortality of male adults from occupational exposures to lead controlled in conformity to currently recommended environmental and biologic standards.