Interpretation of aerial photographs was used to identify historical activities, potential on- and off-site source areas, and other potentially liable parties. Past investigation and remediation costs were assessed, and detailed cost estimates for future remediation activities were prepared to provide cost estimate ranges for site cleanup. Due to the type of contaminants and the regulatory classification of the contaminated soil as Resource Conservation and Recovery Act- or Toxic Substances Control Act-regulated waste, considerable effort was required to develop remediation scenarios enabling estimation of future costs. Technical briefs were prepared for the associated insurance company and legal counsel in support of mediation. Farallon provided technical support during the 2-day mediation process carried out in Alaska and has continued to provide technical support to the insurance company client on complex claims for the past 10 years.