Johnson Wright performed a phased engineering evaluation and financial audit of an environmental cost claim by a Fortune 500 silicon chip manufacturer. The claimed costs totaled approximately $48.1 million in past costs associated with remediation of solvent contamination at three sites located in EPA Region IX. Working in support of a client group comprising multiple insurance companies, Johnson Wright created a comprehensive relational database of the claimed costs. We then collected and reviewed technical and financial documentation to develop an understanding of the activities performed at the sites. Using our understanding of the site histories, Johnson Wright classified the claimed costs into several categories, including business costs, compliance costs, and environmental response costs. We also audited the past costs to determine if they were reasonable and necessary, and organized the claimed costs chronologically to evaluate issues related to claim tender dates. As a result of the audit, Johnson Wright questioned $42.9 million, or 89%, of the claimed past costs. It is our understanding that by using Johnson Wright’s report the client group was able to obtain a settlement whereby the insured withdrew approximately 75% of the amount originally claimed.