Mr. Hansen has eighteen years of professional experience in planning, managing, and conducting scientific and technical investigations.  He has conducted numerous subsurface investigations of soil and groundwater contamination resulting from various chemicals including chlorinated solvents, polychlorinated biphenyls, petroleum hydrocarbons, agricultural pesticides, metals, and leaking underground storage tanks containing fuels and solvents.  He also performs construction observation services and contractor management for remediation projects.  Mr. Hansen is experienced with various methods of soil and groundwater characterization, sample collection, soil boring logging techniques, and preparing and interpreting geologic cross-sections.