Tetra Tech on Small Business Team for $233 Million EPA Region 8 Remedial Action Contract

(PASADENA, Calif. Feb. 13, 2006) -- Tetra Tech, Inc. (NASDAQ:TTEK) announced today that its team led by Pacific Western Technologies, Ltd. (PWT) was awarded the $233 million U.S. Environmental Protection Agency (EPA) Region 8 Remedial Action Contract 2 (RAC 2). The 10-year environmental remediation services contract was procured as a small business set-aside. Tetra Tech will serve as the primary subcontractor to PWT. Tetra Tech will provide technical and management services for environmental cleanup and oversight at Superfund sites throughout EPA Region 8, including sites in Colorado, Montana, Utah, North Dakota, South Dakota, and Wyoming. The contract includes coordination with states and communities in response to releases of hazardous substances, as well as counter-terrorism services. About Tetra Tech (www.tetratech.com) Tetra Tech is a leading provider of consulting, engineering and technical services. With over 7,500 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, 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. CONTACT: Tetra Tech, Inc. Mike Bieber, 626-351-4664

Source: Tetra Tech, Inc.
Date: Feb 13, 2006