Contamination of soil and groundwater by petroleum products is a common problem at Department of Defense facilities. Site-specific human health risk assessments of petroleum contamination, particularly at weathered sites, may save millions of dollars in cleanup costs. However, many risk factors necessary to conduct such risk assessments are not available. Specifically, the risk factor does not exist for long-chain petroleum hydrocarbons (LCPHs) which are components of petroleum products, primarily diesel fuels. This proposal focuses on development of a risk factor for LCPHs in order to facilitate future site-specific health risk assessments at petroleum sites. In addition, a petroleum contamination site at an Air Force installation would be identified for a demonstration study of cleanup costs based on non-risk-based regulatory cleanup standards versus risk-based cleanup standards.