A site assessment or investigation is defined as the process of identifying the presence or likely presence of any hazardous materials on a property, where conditions indicate a release or threatened release of hazardous materials into structures on the property or into soils, groundwater, or surface water on the property.

The purpose of a site assessment or investigation is to gather information about the project area and determine the potential for and/or extent of impacts to the project area from hazardous materials, for us in TxDOT’s decision making process.

According to the Council on Environmental Quality (CEQ), which is responsible for implementing National Environmental Policy Act (NEPA), the requirements of NEPA should be integrated with other planning and environmental review procedures. Therefore, environmental studies established to meet appropriate inquiry or due diligence requirements under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), or to determine appropriate hazardous material management and disposal plans, should be combined with the NEPA process.

FHWA provides general guidelines for identification of hazardous material sites. A copy of this guidance can be found on the :