EPA developed this document to provide EPA regions, states, and tribes with a consolidated reference of toxicity values.  The document provides information on toxicity values, EPA guidance on selecting toxicity values, and other efforts for selecting toxicity values at hazardous waste and cleanup sites.  Appendices A through D provide guidance on calculating risk-based screening levels.  Although developed primarily for typical UST sites, users may find it helpful when addressing petroleum contamination at non-UST sites.    

• Sources Of Toxicity Values For Constituents Of Motor Fuels Relevant To Leaking Underground Storage Tank Site Characterization and Risk Assessment (PDF)(33 pp, 589 K)