Quantitative risk assessment for the exposure to toner emissions from copiers

A quantitative risk assessment was done for the potential cancer risk due to workplace exposure to toner emissions from copiers. Data from carcinogenicity studies with rats were used to calculate the dose-specific risk at the workplace for respirable toner dust (toner-GBP). The result is subject to uncertainties like virtually all dose-specific risk or unit risk values. Experimental mode-of-action data were repeatedly interpreted in terms of clear indication of an effect threshold. In contrast, epidemiological data speak for higher risks from environmental fine dusts without threshold and from occupational exposure to the biodurable carbonaceous core of diesel particles. A long-term time weighted average concentration of 15 mu g/m(3) respirable toner dust may be considered a conservative exposure scenario in offices. We recommend to base the risk characterization of this value on the dose-specific risk at the workplace of 7 (.) 10(-6) per mu g/m(3). If additionally a potentially carcinogenic exposure to benzene emissions is considered a calculated exposure related life-time cancer risk of 1.1 (.) 10(-4) (1 : 9,000) follows.