This unique project required assessment of both subsurface contamination related to the site’s historical use as an unregulated landfill and above grade waste materials illegally disposed of on a 30-acre site and related to the “Silver Shovel” incidents in Chicago and surrounding suburbs. The work performed by Pioneer began as a due diligence project on behalf of a prospective buyer and included a Phase I ESA that required a rigorous review of historical and legal documents that subsequently provided certain evidence and links to an ongoing investigation by the Illinois Attorney General’s Office. A substantial Phase II investigation was then performed that required subsurface testing of the historical landfilled materials and included environmental testing of solid wastes, leachate in monitoring wells installed by Pioneer, an evaluation of methane concentrations, and a preliminary geotechnical investigation. This was complicated by the depth of the landfill which was found at approximately 180 feet and on top of bedrock as well as dealing with extremely high concentrations of methane gas which both required specialized drilling equipment/procedures and constant monitoring for safe working conditions. The second focus of investigation required environmental sampling of soil and waste materials present in berm piles that totaled more than 200,000 cubic yards of material, a large percentage of which was comprised of auto fluff and characteristically hazardous waste. The combined assessment activities completed by Pioneer sufficiently documented site conditions to the satisfaction of the Illinois EPA and subsequent negotiations resulted in one of the few successfully negotiated Prospective Purchaser Agreements with the Illinois Attorney General’s Office. Pioneer, working closely with our client and their attorney, were instrumental in this process. A remedial design and implementation plan were completed by Pioneer to provide overall coordination and oversight of the massive waste removal activities and documentation required to facilitate the eventual redevelopment of this complex and challenging historical landfill site.