TETRA TECH INC

Sustainability is an integral part of our global business, rooted in our internal culture and extending throughout our projects around the world. For more than 50 years, we have leveraged cutting-edge expertise and the latest technology to deliver more sustainable solutions to clients and continually improve the way we do business.

Through our Sustainability Program, we monitor environmental, social and governance ("ESG") metrics, including human capital elements. We continue to enhance the sustainability of our daily practices, reduce our GHG emissions, and provide an exceptional working environment for our employees across our global operations. As a signatory of the United Nations ("UN") Global Compact on human rights, labor, environment and anti-corruption, we embrace the UN Global Compact's Ten Principles as part of the strategy, culture and daily operations of our company.

We actively engage with our stakeholders, internally and externally, to encourage input on the materiality of various ESG issues to Tetra Tech and have incorporated input into our double materiality analysis and sustainability program. Our annual sustainability reporting and key metrics are aligned with the priorities we have set on ethics, human capital, professional development, and health & safety. We report on human capital metrics, including gender balance, racial and ethnic diversity in our workforce, employee engagement and professional development. We have supplier programs that integrate and emphasize sustainability in the procurement of goods and services and subcontracting for our projects. We have reported annually on GHG emissions for more than a decade, significantly reducing our emissions from program inception. In 2021, we expanded our reporting and set new goals for scope 1, 2, and 3 emissions. Based on input from stakeholders and in recognition of the importance of the project work we perform each year, in 2021 we also initiated our Billion People Challenge, with the overarching goal to improve the lives of one billion people by 2030. The Billion People Challenge progress is evaluated each year based on our annual project impact analysis in five categories that are closely aligned with the Global Reporting Initiative standards and the UN Sustainable Development Goals.

Our Sustainability Program is led by our Chief Sustainability Officer, who has been appointed by our Board of Directors and is supported by corporate and operations representatives through our Sustainability Council. We continuously review sustainability-related policies and practices, integrate input from stakeholders, and assess the results of our efforts in order to make future improvements. Tetra Tech's Board of Directors reviews and approves the Sustainability Program and evaluates our progress in achieving the goals and objectives outlined in our plan. As part of our membership in the UN Global Compact, we annually report on the Communication on Progress using Tetra Tech's Sustainability Report.