The Pacific Gas and Electric Company (PG&E) Topock Compressor Station (Station) compresses natural gas so it can be transported through pipelines to PG&E's customers in northern and central California. Historical waste management practices have resulted in potential contamination to both soil and groundwater. From 1951 to 1985, PG&E used hexavalent chromiumHexavalent chromium is a form of chromium. Chromium is a metal naturally found in rocks, soil, and the tissue of plants and animals. Hexavalent chromium can be found naturally at low concentrations, but it is also used in industrial products and processes and is a known carcinogen. On May 28, 2014, the California Department of Public Health adopted a new California drinking water standard at 10 parts per billion for hexavalent chromium. to prevent rust in its cooling towers. From 1951 to 1964, untreated wastewater from the cooling towers was discharged into percolation beds in Bat Cave Wash, a normally dry wash next to the Station. Beginning in 1964, PG&E treated the wastewater to remove hexavalent chromium. The treated wastewater was discharged into Bat Cave Wash until 1968, and subsequently was discharged into an onsite injection well. Over time, PG&E installed a series of lined evaporation ponds for wastewater disposal. In 1985, PG&E stopped using the chromium-based additive and switched to a phosphate-based solution. .

The Station is located in eastern San Bernardino County, about 12 miles southeast of the city of Needles, California, south of Interstate 40, and one-half mile west of the Colorado River. The Station is surrounded by land owned by PG&E, the Fort Mojave Indian Tribe, BNSF Railroad, and the federal government, including the Havasu National Wildlife Refuge managed by the U.S. Fish and Wildlife Service, and lands owned and/or managed by the U.S. Bureau of Reclamation and the Bureau of Land Management (see the Topock Project Site [Site] location map).

  • Phase 1 construction of the groundwater remedy began October 2, 2018 and is anticipated to be completed in 2021. The end of heavy construction is anticipated to be completed in the Spring of 2021. System integration and functional testing is planned for the second and third quarters of 2021, with remedy startup in the Fall of 2021. IM-3 will be turned off when the remedy is started.
  • Preparation of the Soil RFI/RI Report began concurrently with the soil Risk Assessment and is ongoing. It is anticipated to be completed in late 2021.
  • Due to the COVID-19 pandemic, a temporary shutdown of the groundwater remdy construction activities occurred from April 1, 2020 to May 11, 2020. The U.S. Department of the Interior (DOI) directed PG&E to shutdown verbally on March 27, 202 and in writing on April 1, 202. On April 6, 2020, DTSC sent a written concurrence with DOI's direction. Those communications can be found here.
  • As required by the Land Use Covenant entered by PG&E and DTSC, a Soil Management Plan (SMP) for the Compressor Station was submitted on November 1, 2019. 
  • On October 30, 2018, DOI directed PG&E to prepare a Draft Engineering Evaluation/ Cost Analysis (EE/CA). The purpose of an EE/CA is to evaluate the need for a non-time critical removal action (NTCRA) on federal lands or at locations where contamination has the potential to migrate to federal lands. The public comment period for the EE/CA occurred from June 3, 2020 to August 5, 2020. The draft EE/CA can be found here. The DOI will respond to comment received and direct PG&E to revise the draft EE/CA. Current forecast/timeline for the EE/CA can be found here. A fact sheet on the EE/CA can be found here
  • A Fact Sheet - Community Update: Pacific Gas & Electric Company (PG&E) Topock Compressor Station, Environmental Investigation Update was prepared in April 2018 and can be found here.
  • Based on the Final Design, the 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. prepared a Subsequent Groundwater Remedy Environmental Impact Report (SEIR). The April 24, 2018 certified Final SEIR evaluated potential environmental impacts resulting from design details of the selected groundwater remedy (in situ TreatmentTreatment of contamination in place. with Freshwater FlushingMoving of fresh water through the well system to push the plume through an In-Situ Reduction Zone located along National Trails Highway.) that were modified since the approval of the conceptual Groundwater Remediation Project in the 2011 Final Groundwater Remedy EIR and the 2013 Addendum to the EIR.
  • The DTSC, certified the Final SEIR on April 24, 2018, and conditionally approved the groundwater remedy design on April 24, 2018. Construction of the final groundwater remedy system began October 2, 2018.
  • On June 20, 2017, DTSC and DOI determined that the Soil RFI/RI field work was completed and concurred with PG&E to move forward with the risk evaluation process according to the approved Soil Human Health and Ecological Risk Assessment (HHERA) Work Plan and Addendum. The Final Soil HERRA Report was published in October 2019. An Errata was submitted on February 19, 2020. The Soil HERRA and Errata were accepted on Mday 29, 202 by DTSC and DOI. 
  • Soil sampling and related Soil Investigation field work was conducted between December 2015 and March 2016, January through March 2017, and the latter part of April 2017. That work fulfilled the requirements of the Topock Soil Facility Investigation/Remedial Investigation (RFI/RI) Work Plan and Data Gap Work Plans #1, #2, and #3.
  • The Basis of Design/Final (100%) Design Report was submitted by PG&E on November 18, 2015. An errata was submitted on November 18, 2016 and an addendum to the flow and solute transport model was submitted on January 9, 2017. An addendum to the Sil Management Plan (SMP) was submitted on May 28, 2019. On October 8, 2020, PG&E submitted, and DTSC approved, an updated Table to the SMP that incorporated revised values from the Soil HHERA. 

Difficulty Accessing Material?

If you have a disability and have difficulty accessing material on this site please contact us in writing, via email or via telephone and we will work with you to make the information available. Please indicate the nature of the accessibility need, your preferred format (Braille, large print, etc.), what material you are trying to access including where it's located on this site, and how to reach you if questions arise while fulfilling your request. You can direct your requests to:


Written Requests

The Office of Civil Rights
Department of Toxic Substances Control
P.O. Box 806
Sacramento, CA 95812-0806

Email Requests

Telephone Requests

+1 916 324-3095
+1 800 728-6942 - Toll Free