Welcome to the California Department of Toxic Substances Control (DTSC) The department within the California Environmental Protection Agency in charge of the regulation of hazardous waste from generation to final disposal. DTSC oversees the investigation and cleanup of hazardous waste sites.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 Water beneath the Earth’s surface that flows through soil and rock openings (aquifers). and surface waterWater collecting on the ground or in a stream, river, lake, wetland, or ocean. 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 MeasuresCleanup actions taken to protect public health and the environment while long-term solutions are being developed., to ensure that the chromium plumeA body of contaminated groundwater. The movement of a groundwater plume can be influenced by such factors as local groundwater flow patterns, the character of the aquifer in which the groundwater is contained, and the density of contaminants. 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. The groundwater remedy is currently being designed. 

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.