Welcome to the California Department of Toxic Substances Control (DTSC) website for the PG&E Topock Environmental Investigation and Remediation Project (Project) at the Topock Compressor Station (Station) and adjacent land, collectively known as the Topock Project Site (Site). Topock Environmental investigation and remediation activities have been under way at the Site since 1997. 

Protection of California's groundwater and surface water resources, including the Colorado River as well as lands surrounding the Station, is one of DTSC's highest priorities. In 2004 DTSC directed the Pacific Gas and Electric Company (PG&E) to take immediate, but temporary actions, known as Interim Measures, to ensure that the chromium plume beneath the Site flows away from the Colorado River while additional investigation and final cleanup options are evaluated. In January 2011, DTSC adopted a Final Remedy for the groundwater contamination based on PG&E's study of the Site and certified the Final Environmental Impact Report. The U.S. Department of the Interior (DOI), as a co-regulatory agency overseeing the Site, also adopted a Groundwater Record of Decision, in December 2010, and selected the same remedy for the groundwater cleanup. 

This website provides an overview of current Site activities and other Site-related information. Information on this website includes:

  • Station and Site location and history
  • Investigation and cleanup activities: past, present and future
  • Public Involvement Information
  • Cleanup-related technical reports and work plans

To visit DTSC on our main website go to www.dtsc.ca.gov.