Lessons Learned Using Fractions to Assess Risk at Petroleum Release Sites

Total petroleum hydrocarbon (TPH) fractional analysis and tiered risk assessments at petroleum release sites are replacing cleanup approaches based upon total TPH concentrations. Field demonstrations of the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG) approach for assessing human health risk at petroleum release sites were performed at eight Department of Defense installations. One site also provided an opportunity to demonstrate the Massachusetts Department of Environmental Protection methodology and compare the approaches. Two lessons learned from the field demonstrations were: (1) TPH fractional analysis approaches provide a scientific bases for assessing risk and implementing appropriate criteria alone; and (2) the TPHCWG approach should not be used at relatively fresh petroleum product release sites because benzene, a known human carcinogen, is likely to be present at concentrations high enough to dominate cleanup decisions.