EPA Completes Reviews at 27 Superfund Sites Across the Pacific Southwest

As a key indicator of the advancement of long-term Superfund cleanups, U.S. Environmental Protection Agency (EPA) completed comprehensive reviews of cleanups at 27 Superfund sites across Arizona, California, Hawaii and Nevada in Fiscal Year 2025. 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 webpage.

The reviews completed in 2025 are:

Arizona

• Mountain View Mobile Homes, Globe, Ariz.
• Nineteenth Avenue Landfill, Phoenix, Ariz.
• Phoenix-Goodyear Airport Area, Goodyear, Ariz.
• Yuma Marine Corps Air Station, Yuma, Ariz.

California

• Applied Materials, Santa Clara, Calif.
• Casmalia Resources, Casmalia, Calif.
• CTS Printex, Inc., Mountain View, Calif.
• Del Amo, Los Angeles, Calif.
• Fresno Municipal Sanitary Landfill, Fresno, Calif.
• Hewlett-Packard (620-640 Page Mill Road), Palo Alto, Calif.
• Intersil Inc./Siemens Components, Cupertino, Calif.
• J.H. Baxter & Co., Weed, Calif.
• Liquid Gold Oil Corp., Richmond, Calif.
• Lorentz Barrel & Drum Co., San Jose, Calif.
• Mather Air Force Base (AC&W Disposal Site), Mather, Calif.
• Moffett Field Naval Air Station, Moffett Field, Calif.
• Montrose Chemical Corp., Torrance, Calif.
• Norton Air Force Base (Landfill 2), San Bernardino, Calif.
• Operating Industries, Inc., Landfill, Monterey Park, Calif.
• Pemaco Maywood, Maywood, Calif.
• Rockets, Fireworks, and Flares Site, Rialto, Calif.
• Southern California Edison Co. (Visalia Pole Yard), Visalia, Calif.
• South Bay Asbestos Area, Alviso, Calif.
• Tracy Defense Depot (USARMY), Tracy, Calif.

Hawaii

• Del Monte Corp. (Oahu Plantation), Kunia, Hawaii
• Naval Computer and Telecommunications Area Master Station Eastern Pacific, Wahiawa, Hawaii

Nevada

• Anaconda Copper Mine, Yerington, Nev.

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, which also undergo Five-Year Reviews. EPA must ensure that any redevelopment will uphold the protectiveness of the remedy into the future.

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 143 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.