Investor Presentaiton

STN TSX NYSE EXCELLENCE INNOVATION PEOPLE GROWTH 1000 800 600 400 200 Environmental Services Planning and permitting services for private sector clients, and remediation activities for private and public sector clients 14% % of Net Revenue Q2 2020 YTD Net Revenue (C$ Millions) CAGR 9.5% 0 2017 2018 2019 LTM Q2 2020 9 Barrow Island Vegetation Recognition Barrow Island, Australia Net revenue by sector Q2 2020 YTD ■Mining ■Community Development ■Transportation ■ Power & Dams Buildings ■ Water ■ Oil & Gas Net revenue by geography Q2 2020 YTD ■ Global ■Canada ■ United States

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