Response to: Mortality among rubber chemical manufacturing workers by M.M. Prince et al. Am. J. Ind. Med. 2000. 37: 590–598.

Mary M. Prince and colleagues [Prince et al., 2000] report that workers in the "rubber chemicals" manufacturing department of a plant in Niagara County, New York, have elevated ischemic heart disease (IHD) mortality compared with the US population, based on their observation of a standardized mortality ratio (SMR) for IHD of 1.51 (95% CI 0.94-2.3). Despite the fact that the investigators also report SMRs for IHD mortality of 1.19 when compared with local Niagara County, NY referent rates and a rate ratio of 1.03 when workers exposed to rubber chemicals were compared with workers in other departments of the plant, most discussion and interpretation of these results focus on the comparison with US rates.