Advanced contamination assessments are performed on properties that have identified contamination. These assessments are usually defined by state regulatory agencies and are performed in accordance with state-specific assessment standards. The assessments often involve extensive interaction with regulators charged with oversight and approval of site assessment work. These assessments generally include numerous soil borings and the installation of groundwater monitoring wells to define the lateral and vertical extent of contamination. Soil and groundwater aquifer properties are also evaluated through physical testing. The contamination assessment results are used to evaluate the necessity and advisability of remediation and provide estimated costs of any proposed remedial project.