Hazardous materials may be encountered on practically any transportation project. Additionally, hazardous material sources can be found in existing, adjacent, and proposed ROW. Consequently, the potential for hazardous materials should be assessed as early as possible when developing transportation plans or during project programming and development.

Hazardous materials/waste sites can pose a myriad of legal, regulatory, financial and technical problems to the department. TxDOT becomes exposed to substantial liability when it purchases contaminated parcels of land or if it owned property when waste was disposed of there (either by past agency practices, by third-party illegal disposal practices or by the activities of tenants). Under several federal and state statutes, claims can be made against the department for a variety of cleanup costs, as well as for personal or property damages. In addition to these costs, the additional time delay that results from cleaning up a contaminated site can add significantly to overall projects costs.

TxDOT conducts Initial Site Assessment (ISA) to identify potential contamination, waste, or other hazardous materials related issues for TxDOT construction and maintenance projects.