RT Journal Article SR Electronic T1 Lymphohaematopoeitic cancer mortality among workers with benzene exposure JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 676 OP 679 DO 10.1136/oem.60.9.676 VO 60 IS 9 A1 Collins, J J A1 Ireland, B A1 Buckley, C F A1 Shepperly, D YR 2003 UL http://oem.bmj.com/content/60/9/676.abstract AB Lymphohaematopoeitic cancer mortality was examined among 4417 workers at a chemical plant by cumulative and peak benzene exposure. There was little evidence of increasing risk with increasing cumulative exposure for all leukaemias or acute non-lymphocytic leukaemias (ANL), or the other lymphohaematopoeitic cancers with the exception of multiple myeloma. For multiple myeloma, the SMRs were 1.1 (95% CI 0.3 to 2.5) in the non-exposed group, 1.4 (95% CI 0.2 to 5.1) in the <1 ppm-years, 1.5 (95% CI 0.2 to 5.4) in the 1–6 ppm-years, and 2.6 (95% CI 0.7 to 6.7) in the >6 ppm-years group. We found no trends by peak exposures for any of the cancers. However, when peak exposures over 100 ppm for 40 or more days were considered, the observed number of all leukaemias (SMR = 2.7, 95% CI 0.8 to 6.4), ANL (SMR = 4.1, 95% CI 0.5 to 14.9), and multiple myeloma (SMR = 4.0, 95% CI 0.8 to 11.7) were greater than expected. While the observed number of deaths is small in this study, the number of peak exposures greater than 100 ppm to benzene is a better predictor of risk than cumulative exposure. The dose rate of benzene and a threshold for exposure response may be important factors for evaluating lymphohaematopoietic risk.