Public Notice: EPA Pacific Southwest (Region 9) Completes Five-Year Reviews at 25 Superfund Sites in 2026

Summary

As a key indicator in the advancement of long-term Superfund cleanups, U.S. Environmental Protection Agency (EPA) completed comprehensive reviews of cleanups at 25 Superfund sites across Arizona and California in Fiscal Year 2026. As required by law, EPA performs reviews every five years at Superfund sites to ensure that cleanup efforts are continuing to protect human health and the environment.

EPA conducts five-year reviews at Superfund sites where waste remains in-place, after cleanups have been initiated. These comprehensive reviews help ensure that EPA continues to evaluate the performance of long-term cleanup efforts and determines whether any further action to protect human health or the environment is required. Results of each of the five-year reviews can be found on the individual Superfund site’s website.

The reviews completed in 2026 are:

Arizona

• Hassayampa Landfill, Arlington, Ariz.
• Indian Bend Wash Area, Scottsdale, Ariz.
• Motorola Inc. (52^nd Street Plant), Phoenix, Ariz.
• Williams Air Force Base, Chandler, Ariz.

California

• Aerojet General Corporation, Rancho Cordova, Calif.
• Alameda Naval Air Station, Alameda, Calif.
• Atlas Asbestos Mine, Coalinga, Calif.
• Brown & Bryant (Arvin Plant), Arvin, Calif.
• Coalinga Asbestos Mine, Coalinga, Calif.
• Coast Wood Preserving, Ukiah, Calif.
• Concord Naval Weapons Station, Concord, Calif.
• Cooper Drum Company, South Gate, Calif.
• Edwards Air Force Base, Edwards AFB, Calif.
• George Air Force Base, Victorville, Calif.
• Lava Cap, Nevada County, Calif.
• Lawrence Livermore Natl Lab (Site 300) (USDOE), Tracy, Calif.
• Pacific Coast Pipeline, Fillmore, Calif.
• Purity Oil Sales, Malaga, Calif.
• Riverbank Army Ammunition Plant, Riverbank, Calif.
• San Gabriel Valley (Area 1), El Monte, Calif.
• San Gabriel Valley (Area 4), La Puente, Calif.
• Selma Pressure Treating Company, Selma, Calif.
• Stringfellow, Jurupa Valley, Calif.
• United Heckathorn, Richmond, Calif.
• Westinghouse Electric Corporation, Sunnyvale, Calif.

Background

Throughout the process of designing and constructing a Superfund cleanup (also called a remedy) at a hazardous waste site, EPA's primary goal is to make sure the remedy will be protective of public health and the environment. After the remedy has begun to move forward, EPA continues to ensure it remains protective by requiring reviews of cleanups every five years. It is important for EPA to regularly check on these sites to ensure the remedy is working properly. These reviews identify issues (if any) that may affect the protectiveness of the constructed remedy and, if necessary, recommend action(s) necessary to address them.

There are many phases of the Superfund cleanup process, including considering future use and redevelopment of sites as well as conducting post-cleanup monitoring of sites. EPA must ensure that any redevelopment will uphold the protectiveness of the remedy into the future.

More Information

The Superfund program, a federal program established by Congress in 1980, investigates and cleans up the most complex, uncontrolled or abandoned hazardous waste sites in the country and endeavors to return them to productive use. In total, there are 140 Superfund sites (this includes sites currently on the National Priorities List, sites deleted from that List as the cleanups have been completed, and sites under the Superfund Alternative Approach program) across EPA’s Pacific Southwest Region.