A remedial investigation was conducted for the thirteen sites that comprise the Operable Unit (OU) 3A at MCAS (Marine Corps Air Station) El Toro (Figures 1 and 2), a Department of Navy [DON] lead agency facility, utilizing an innovative risk based approach to develop sampling strategies and innovative field procedures to implement this strategy. This approach included the collection of a limited number of samples (determined statistically) at each site to calculate the human health risk at the sites. As part of Comprehensive Environmental Resource Conservation and Liability Act (CERCLA) process, remedial investigations needed to be conducted at the OU-3A Sites (Figure 3). Base Realignment and Closure (BRAC) has designated MCAS El Toro to be closed in July 1999. Therefore, the DON indicated that accelerated investigation to support the President’s five point plan for making property available to the community for reuse, needed to be maximized in a short period of time in order to release these properties to the Local Reuse Agency. A key to expediting closure of the OU-3A Sites was the approach used to implement the field investigation and innovative presentation of the risk based sampling results in the remedial investigation.