The lead scavengers Ethylene Dibromide (EDB) and 1,2-Dichloroethane (1,2-DCA) were added to leaded motor gasoline to prevent the buildup of deposits of lead oxide inside internal combustion engines. Recent studies demonstrate that lead scavengers may persist for long periods of time in certain ground water environments. Although lead and lead scavengers were phased out in conventional motor gasoline by the end of the 1980s, the lead scavengers from old releases may continue to contaminate ground water at many gasoline service station sites. In addition, aviation gasoline (Avgas) contains lead scavengers, and gasoline containing lead scavengers is still used for certain off-road applications such as automobile racing. There is a significant possibility that lead scavengers from releases of leaded gasoline pose an ongoing risk to ground water quality...EPA has formed a team with the Association of State and Territorial Waste Management Officials to determine the scope and magnitude of the occurrence of lead scavengers at leaking UST sites. The team developed a three-phased approach to this problem: (1) developing an understanding of the magnitude of the potential problem by compiling existing background information, (2) assessing gaps in current knowledge, based on the findings of Phase 1, and implementing appropriate measures to fill the gaps, and (3) determining an appropriate response based on evaluation of the results of Phases 1 and 2.