A cohort study of uranium millers and miners of Grants, New Mexico, 1979–2005

Abstract

A cohort mortality study of workers engaged in uranium milling and mining activities nearGrants, New Mexico, during the period from 1955 to 1990 was conducted. Vital status wasdetermined through 2005 and standardised mortality ratio (SMR) analyses wereconducted for 2745 men and women alive after 1978 who were employed for at leastsix months. Overall, mortality from all causes (SMR 1.15; 95% CI 1.07–1.23;n = 818) and all cancers (SMR 1.22; 95% CI 1.07–1.38;n = 246) was greater than expected on the basis of US mortality rates. Increasedmortality, however, was seen only among the 1735 underground uraniumminers and was due to malignant (SMR 2.17; 95% CI 1.75–2.65;n = 95) and non-malignant (SMR 1.64; 95% CI 1.23–2.13;n = 55) respiratory diseases, cirrhosis of the liver (SMR 1.79;n = 18) and externalcauses (SMR 1.65; n = 58). The lung cancer excess likely is attributable to the historically high levels of radon inuranium mines of the Colorado Plateau, combined with the heavy use of tobaccoproducts. No statistically significant elevation in any cause of death was seenamong the 904 non-miners employed at the Grants uranium mill. Among 718 millworkers with the greatest potential for exposure to uranium ore, no statisticallysignificant increase in any cause of death of a priori interest was seen, i.e., cancers ofthe lung, kidney, liver, or bone, lymphoma, non-malignant respiratory disease,renal disease or liver disease. Although the population studied was relativelysmall, the follow-up was long (up to 50 yrs) and complete. In contrast to minersexposed to radon and radon decay products, for uranium mill workers exposed touranium dusts and mill products there was no clear evidence of uranium-relateddisease.