Committed to safety, reliability and environmental stewardship

View of Topock Compressor Station near Needles, California and the Colorado River.

The Topock Compressor Station is located in eastern San Bernardino County, approximately 12 miles southeast of Needles, and has played an important role in supplying natural gas to our service areas in Central and Northern California since 1951.

Topock Compressor Station and others like it are needed to safely pressurize natural gas, moving it through hundreds of miles of pipeline on its way to homes, businesses and other gas customers.

The temperature of natural gas increases during compression, and the gas must be moved to cooling towers. To prevent corrosion of cooling tower equipment prior to 1985, Industry Standard added chromium compounds to the water used in the cooling towers and other equipment.

This practice was employed at the Station until 1985, with cooling tower wastewater containing hexavalent chromium being discharged into the adjacent area through 1964. Additionally, historical waste handling and disposal practices resulted in the contamination of soils in certain areas at and around the Station.

In our commitment to safety, reliability and environmental stewardship at the Topock Compressor Station, PG&E voluntarily partnered with numerous entities going back to 1996 to address these issues.
Partners include the California Department of Toxic Substances Control (DTSC), the U.S. Department of the Interior (DOI), several nearby communities and Native American Tribes. Tribal and agency representatives play a vital role in monitoring our daily project activities.

Comprehensive Environmental Remedy Program

Extensive environmental studies have been conducted at the Topock Compressor Station and surrounding area. These studies guide cleanup and stewardship activities and ensure compliance with all operating permits and regulatory requirements for the Topock Remedy Construction Project. For example:

  • Our preliminary investigations included more than 1,000 soil samples at 364 locations, trenching at 15 locations, and collection of sediment and pore water samples from 10 locations at the edge of the Colorado River.
  • A final cleanup plan is in place to treat groundwater (underground water in soil and rock beneath the Station) that contains hexavalent chromium from historical operations at the Station. Interim cleanup measures in place since 2005 have been treating groundwater.
  • Construction of the final remedy began October 2018 with completion anticipated to take approximately two years. Once complete, the remedy will remain in place for approximately 30 years.
  • Long-term monitoring of Colorado River water continues to confirm that no hexavalent chromium is in the river and none has ever been detected in any river or sediment samples taken near the Station.

Learn more about the Topock Program

Visit our Topock cleanup page and DTSC’s project websiteOpens in new Window.. You may also download the following program fact sheets:

Read about accomplishments and other Topock project highlights (PDF, 590 KB)

Learn more about recent activities in this DTSC factsheet about Topock (PDF, 1.42 MB)
Contact Us

Contact us about the cleanup

If you have any questions about the compressor station or our cleanup efforts, call us at 1-866-247-0581 or email us at

Get more details

Get more details

The DTSC Topock Project website provides more details about the cleanup, including photos, schedules, and a document repository. Visit PG&E Topock Compressor Station Environmental Investigation and Cleanup Activities.

More information icon

Learn more about cleanup efforts

Get more information about our cleanup efforts at Topock and Hinkley Compressor Stations in San Bernardino County. Visit Hinkley Compressor Station and Topock Compressor Station Cleanup.