|TRG's client is the leading supplier of ketone peroxides in North America, supplies specialty chemicals to the metallic stearate market and also produces Active Pharmaceutical Ingredients (APIs). TRG's client specializes in complex multi-stage organic synthesis and separation. The site is located in the San Gabriel Valley Superfund area within the Baldwin Park Operable Unit. Groundwater in the site vicinity is known to be contaminated. Depth to groundwater is more than 200 feet below ground surface. Drilling conditions at the site are difficult due to the presence of cobbles and boulders in the subsurface. The Reynolds Group was originally hired by its client in 1996 to perform an assessment. Because of The Reynolds Group's work, the client contacted us in 2004 to perform additional consulting services. Our client was in the process of obtaining closure for one of the areas of concern identified by the California Department of Toxic Substances Control (DTSC). During the DTSC visit to the site, the DTSC observed conditions requiring further investigation. The Reynolds Group prepared and implemented the RCRA Facility Investigation Work Plan, DTSC Corrective Action, Current Conditions Reports, and assisted with the Public Participation requirements of the DTSC. The Reynolds Group participated in meetings with DTSC staff to negotiate realistic assessment work scopes. Investigation methods included: soil gas sampling, soil gas probe installation and sampling, soil boring advancement with sonic drilling techniques, and shallow direct push (probing) methods.