"June 1987"--T.p. "MTR-86W140"--T.p. "Sponsor: U.S. Environmental Protection Agency"--T.p. "Contract no.: EPA 68-01-7054"--T.p. EPA 540-R-87-013, per NSCEP's publication title list. Includes bibliographical references.

This report presents an analysis of the target distance limit employed in the EPA Hazard Ranking SYstem (HRS) air pathway. The target distance limit is defined as the maximum distance used in determining the target population in the air pathway. The report presents estimates of the general level of cancer risk arising from air emissions from uncontrolled waste sites and examines the implications of the analysis for the targets category of the HRS air pathway. The principle conclusions reached in the analysis are: (1) simple risk analysis techniques can be fruitfully employed in HRS issue analyses, although their use in assessing actual site risks based on the data developed during site inspections is unwarranted, (2) the uncertainty associated with the results is high and generalizations must be made with caution, (3) cancer risks to individuals living beyond 4 miles from the boundary of a site from long-term exposures to air emissions from most uncontrolled waste sites are probably very low (as are their risks from chronic exposures to non-carcinogenic contaminants with safe exposure thresholds), (4) risks from these effects to individuals living beyond 1/4 from the boundary of a site are also probably low, (5) risks to individuals residing with 1/4 mile of site boundaries are difficult to assess using techniques such as are employed here and are probably higher than indicated in this study, and (6) particulate emissions from large sites may pose a higher, potentially unacceptable, cancer risk than is indicated by this analysis. The major implications for the HRS air pathway are as follows: (1) the target distance limit cannot be definitively set based on the results of this analysis,m further analysis of sub-chronic risks must be undertaken before a revision of the four-mile limit is made, (2) cancer risk should not be emphasized in the HRS air pathway, and (3) differential cancer risks between sites can best be reflected in the toxicity and waste quantity components of the HRS waste characteristics category.