Tetra Tech Awarded $200 Million Environmental Support Services Contract with the U.S. Department of Energy

Tetra Tech, Inc. (NASDAQ: TTEK) announced today that it has been awarded a nationwide contract to provide National Environmental Policy Act (NEPA) support services for the U.S. Department of Energy (DOE)/National Nuclear Security Administration (NNSA) and the Federal Energy Regulatory Commission (FERC). Three large business and four small business contractors will share in the $200 million contract ceiling. The indefinite delivery/indefinite quantity contract has a two-year period of performance and three one-year option periods. This is the third consecutive time that DOE has selected Tetra Tech as its nationwide NEPA services provider.

Tetra Tech will prepare environmental impact statements, environmental assessments, and related environmental documentation as required by NEPA, the Nuclear Regulatory Commission, and state and federal regulations.

Tetra Tech will provide these services in support of nuclear license application reviews; nuclear stockpile management; spent nuclear fuel management; transportation, treatment, storage, and disposal of radioactive and hazardous materials and waste; and decommissioning, decontamination, and disposal of nuclear and support facilities, among other applications. DOE also anticipates the need for NEPA support services for reviews of energy management/conservation initiatives and power generation and alternative fuel production projects. The energy projects may involve commercial nuclear power, clean coal/carbon sequestration, wind, solar, fuel cells, biomass, ethanol, and other emerging technologies.

About Tetra Tech (www.tetratech.com)

Tetra Tech is a leading provider of consulting, engineering, program management, construction and technical services addressing the resource management and infrastructure markets. The Company supports government and commercial clients by providing innovative solutions focused on water, the environment and alternative energy. With more than 8,500 associates located in the United States and internationally, Tetra Tech’s capabilities span the full project life cycle.

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.