MSE professionals use ecological and human health risk assessment as a basis for remedial action decisions. We have completed complex risk assessments for hazardous waste sites in accordance with EPA Risk Assessment Guidance for Superfund (RAGs) and State-specific Risk-Based Corrective Action (RBCA) programs for petroleum-contaminated sites. Our staff members have received recognition from the USEPA for their participation in the development and implementation of a State RBCA program. MSE's technical capabilities in the areas of hydrogeology, groundwater modeling, and statistical analysis enable our professionals to anticipate and acquire the data needed to evaluate contaminant fate and transport and exposure point concentrations to conduct risk assessments. Our in-house computer software capabilities for risk assessments include Microsoft Excel and Access, the GSI RBCA Spreadsheet system and the GSI RBCA Tool Kit for Chemical Releases, the Johnson & Ettinger Model for evaluating subsurface vapor migration into buildings as well as two and three-dimensional modeling programs including MODFLOW and several EPA programs.