GSI engineers and scientists have led or participated in the assessment and cleanup of numerous sites regulated under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as Superfund. We have expertise in all facets of the National Contingency Plan and the CERCLA process from conducting interim removal actions and remedial investigations to performing remedial design, remedial actions, and providing long-term operation and maintenance. Our hydrogeologists and data scientists have also assisted USEPA with performing groundwater monitoring optimization as part of Five Year Reviews completed under CERCLA. GSI engineers have utilized principles of adaptive site management, including refinement of conceptual models, feasibility studies, plume stability studies, and pilot testing to arrive at cost-effective remedial solutions that combine active and passive approaches for management of these complex sites. GSI’s testifying experts have also provided testimony in federal courts on numerous CERCLA liability and cost allocation matters.