EPA Pacific Southwest (Region 9) to perform Five-Year Reviews at 25 Superfund sites in 2026

In an important marker of progress achieved on long-term Superfund cleanups across the Pacific Southwest region, in 2026 the U.S. Environmental Protection Agency (EPA) will perform comprehensive Five-Year Reviews of cleanups at 25 Superfund sites across Arizona and California. EPA will undertake these legally required reviews to ensure that cleanup efforts, some of which were completed years ago, continue to be protective of public health and the environment.

Once the Five-Year Reviews are complete, the findings will be posted to each Superfund site’s webpage. The reviews to be 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 Corp., Rancho Cordova, Calif.
• Alameda Naval Air Station, Alameda, Calif.
• Atlas Asbestos Mine, Coalinga, Calif. 
• Brown & Bryant, Inc. (Arvin Plant), Arvin, Calif.
• Coalinga Asbestos Mine, Coalinga, Calif.
• Coast Wood Preserving, Ukiah, Calif.
• Concord Naval Weapons Station, Concord, Calif.
• Cooper Drum Co., South Gate, Calif.
• Edwards Air Force Base, Edwards AFB, Calif.
• George Air Force Base, Victorville, Calif.
• Lava Cap Mine, Nevada City, Calif.
• Lawrence Livermore Natl Lab (Site 300) (USDOE), Tracy, Calif.
• Pacific Coast Pipeline, Fillmore, Calif.
• Purity Oil Sales, Inc., 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 Co., Richmond, Calif.
• Westinghouse Electric Corp. (Sunnyvale Plant), 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 facilitate activities to return them to productive use. In total, there are 140 Superfund sites (this includes sites currently on the National Priorities List, deleted sites, and sites under the Superfund Alternative Approach program) across EPA’s Pacific Southwest Region.