Terra Mentis staff worked developed a risk assessment scoping document that described all of the assumptions and approaches to be used in the preparation of the human health and ecological risk assessment for this active refinery in Billings MT. Dr. Foster subsequently prepared the human health and ecological risk assessments for the Refinery in accordance with the scoping document and appropriate USEPA risk assessment guidance. Risk assessment activities were extended over a period of seven years for this client and have included subsequent evaluations of the Exxon Fire Training Areas and various process areas. The project has involved extensive negotiations with U.S. EPA Region VIII on behalf of the client.