How were the cancer risk estimates affected by EPAs recently revised Guidelines for Carcinogen Risk Assessment (EPA/630/P-03/001F) and new Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens (EPA/630/R-03/003F)?
The revised Guidelines were released after the risk calculations for the national-scale assessment were completed. However, the effective guidance at the time we calculated the risks (an earlier draft of the revised Guidelines) was consistent in most ways with the revised document. There was one important exception to this consistency, however. The cancer guidelines now include Supplemental Guidance that makes new recommendations with regard to estimating cancer risks to children. These recommendations have not been implemented for the chemicals included in the national-scale assessment, with the exception of vinyl chloride. The Supplemental Guidance recommends that risks to children be adjusted for carcinogenic chemicals acting through a mutagenic and linear mode of action (i.e., chemicals that cause cancer by damaging genes). Where available data for the chemical are adequate they should be used to develop age-specific potency values, as EPA has already done for vinyl chloride (and w
