September 29, 2008

Tetra Tech Awarded $48 Million U.S. EPA Environmental Response Training Program

Tetra Tech, Inc. (NASDAQ: TTEK) announced today that it has been awarded the $48 million Environmental Response Training Program (ERTP) by the U.S. Environmental Protection Agency (U.S. EPA). Tetra Tech will provide nationwide environmental response training services for federal, state and local government employees, including training in hazardous waste sampling, groundwater investigation, decontamination, and emergency response. The cost-plus-fixed-fee contract has a three-year base period and two option periods of two years each. Tetra Tech has provided environmental response training and other training to the U.S. EPA for more than 22 years.

About Tetra Tech (

Tetra Tech is a leading provider of consulting, engineering, and technical services. With approximately 8,500 associates located in the United States and internationally, the Company supports commercial and government clients in the areas of resource management and infrastructure. Tetra Tech's services include research and development, applied science and technology, engineering design, program management, construction management, construction, and operations and maintenance.

Any statements made in this release that are not based on historical fact are forward-looking statements. Any forward-looking statements made in this release represent management's best judgment as to what may occur in the future. However, Tetra Tech's actual outcome and results are not guaranteed and are subject to certain risks, uncertainties and assumptions ("Future Factors"), and may differ materially from what is expressed. For a description of Future Factors that could cause actual results to differ materially from such forward-looking statements, see the discussion under the section "Risk Factors" included in the Company's Form 10-K and 10-Q filings with the Securities and Exchange Commission.