What does EPA believe constitutes an acceptable level of risk?
Unlike other pollutants which EPA regulates, for air toxics there are no risk levels that represent acceptable or unacceptable regulatory thresholds. However, EPA has made case-specific determinations such as the 1989 Benzene National Emission Standard for Hazardous Air Pollutants (NESHAP) that set up a two part risk-based decision framework. First, it set an upper limit of acceptability of 1 in 10,000 lifetime cancer risk for highly exposed individuals. Second, it set a target of protecting the greatest number of persons possible to an individual lifetime risk level no higher than approximately 1 in 1,000,000. In addition, these determinations called for considering other health and risk factors, including the uncertainty in the risk assessment, in making an overall judgment on acceptability. This assessment, however, is not designed to be a definitive tool for determining risk since it has many limitations in data and methods. In addition, this assessment estimates average population
