Suh M, Crump K, Mittal L, Hirsch S, Valdes Salgado R, BartlettC, Van Landingham C, Rohr A, Proctor DM. Inhalation cancer risk assessment of hexavalent chromium based on updated mortality for Painesville chromate production workers. Presented at the Society of Toxicology’s 55th Annual Meeting, New Orleans, LA, March 13-17, 2016.
The exposure-response for hexavalent chromium [Cr(VI)]-induced lung cancer among workers of the Painesville Ohio chromate production facility has been used internationally for quantitative risk assessment of environmental and occupational exposures to airborne Cr(VI). We updated the mortality of 714 Painesville workers (including 198 short-term workers) through December 2011, reconstructed exposures, and conducted exposure-response modeling using Poisson and Cox regressions to provide quantitative lung cancer risk estimates. With this investigation, we were able to control for significant lung cancer risk factors including smoking and age at hire in the derivation of β values and unit risk estimates. The average length of follow-up was 34.4 years with 24,535 person-years at risk. Lung cancer was significantly increased for the cohort (standardized mortality ratio [SMR] =186; 95% confidence interval [CI] 145 – 228), for those hired before 1959, those with > 30 years tenure, and those with cumulative exposure >1.41 mg/m3-years or highest monthly exposures > 0.26 mg/m3. Of the models assessed, the linear Cox model with unlagged cumulative exposure provided the best fit and was preferred. Smoking and age at hire were also significant predictors of lung cancer mortality. Adjusting for these variables, the occupational unit risk was 0.00166 (95% CI 0.000713 – 0.00349), and the environmental unit risk was 0.00832 (95% CI 0.00359 – 0.0174), which are 20% and 15% lower, respectively, than values developed in a previous study of this cohort. Due to the use of updated mortality data and refined dose-response modeling approaches, this study provides improved information for assessing the potential cancer risk associated with exposure to Cr(VI).