Written by Michelle Whitmer | Scientifically Reviewed By Arti Shukla, Ph.D. | Edited By Walter Pacheco | Last Update: July 16, 2024

Quick Facts About Asbestos in California
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Asbestos Exposure in California

California’s extensive asbestos deposits have placed residents and workers at risk of exposure. According to the California Department of Public Health, 45 of California’s 58 counties have asbestos deposits.

Many California Superfund sites contain asbestos. The U.S. Environmental Protection Agency lists several sites as priorities because of the asbestos risks.

For example, Hunters Point Naval Shipyard used a lot of asbestos. This threat has endangered Navy veterans. A W.R. Grace site processed asbestos and contaminated the surrounding area. It created an exposure risk for nearby residents.

California was home to the last asbestos operation in the country. The King City Asbestos Company operated in the Coalinga asbestos district of San Benito and Fresno Counties. The mine worked a large chrysotile deposit until it closed in 2002. The city of Coalinga became a Superfund because mining spread asbestos particles throughout the town.

El Dorado Hills is another risky area, as it is home to one of the largest asbestos deposits in the world. Residents take measures to cut the risk of asbestos exposure.

California’s deposits and workplace exposure has made it a hotspot for asbestos litigation. In 2004, a Superior Court judge from San Francisco said asbestos cases made up 25% of the court’s docket.

California’s Occupations and Environmental Areas at Risk

In addition to asbestos deposits, certain jobs presented a high asbestos exposure risk. Military bases, shipyards and mining operations exposed veterans and workers.

Some companies and government agencies have remediated sites of asbestos contamination.

California Naval Shipyard

Asbestos affected several locations in the now-closed West Coast shipyard. In November 2003, the U.S. Navy released information on its plan to build a groundwater containment barrier and extraction trench. The goal is to prevent contaminated groundwater from entering the wetlands and tidal marshes.

Hunters Point Naval Shipyard

The Hunters Point Naval Shipyard in San Francisco was the first dry dock on the Pacific Coast. The Navy used it for shipbuilding, repair and maintenance activities. After World War II, activities in the shipyard ranged from ship repair to submarine servicing and testing. In 1987, tests confirmed the presence of asbestos, polychlorinated biphenyls (PCBs), pesticides and lead. The EPA placed it on the Superfund National Priorities List, and the shipyard shut down in 1991.

In 1990, workers removed asbestos from 24 areas on the site. They removed an estimated 226,000 square feet of asbestos-contaminated materials. The removal continued for years, and the Navy completed the job in 1995. The Bay Area Air Quality Management District has said that remaining asbestos does not pose a threat to the general public.

Moore Dry Dock Company

The More Dry Dock Company also used a lot of asbestos on vessels. Juries have awarded large sums to plaintiffs in asbestos cases against the shipyard.

In 2001, the family of a merchant seaman who served on two Moore-built cargo ships received $700,000 in damages. The jury found Moore liable for the seaman’s death from mesothelioma. The United States Maritime Commission in 1942 had notified Moore about the dangers of asbestos.

In a 2000 case, a jury awarded $10.35 million to the husband of a woman who had worked in the Moore Dry Dock shipyard during World War II. The jury found the woman was also exposed to fibers on the clothes of her husband who worked as a pipefitter for more than 30 years.

Other Superfund sites in California that could contain asbestos materials:

  • Alameda Naval Air Station, Alameda
  • Edwards Air Force Base, Lancaster
  • El Toro Marine Corps Air Station, Irvine
  • Mather Air Force Base, Sacramento
  • Sacramento Army Depot, Sacramento
  • George Air Force Base, Victorville
  • Tracy Defense Depot, Tracy
  • Travis Air Force Base, Fairfield
  • Concord Naval Weapons Station, Concord
  • Castle Air Force Base, Atwater
  • March Air Force Base, Riverside
  • McClellan Air Force Base, Sacramento
  • Barstow Marine Corps Logistics Base, Barstow
  • Norton Air Force Base, San Bernardino
  • Sharpe Army Depot, Lathrop
  • Naval Air Station Moffett Field, Santa Clara
  • Riverbank Army Ammunition Plant, Modesto
  • Camp Pendleton Marine Corps Base, San Diego County

Former California Zonolite/W.R. Grace & Company Site

The former California Zonolite/W.R. Grace & Company site posed similar health concerns. The 2.75-acre California Zonolite facility was in operation from 1950 to 1977. In 1966, W.R. Grace & Company purchased the Glendale facility. The company used the facility to process vermiculite. It came from Libby, Montana.

and contained asbestos at levels of 0.3 percent to 7 percent. According to the Agency for Toxic Substances and Disease Registry, or ATSDR, the facility received more than 120,000 tons.

An estimated 1,750 people lived within one mile of the site. They may have suffered environmental exposure to asbestos debris. ATSDR said an estimated 70 to 150 former W.R. Grace employees got exposed to asbestos on the job. W.R. Grace filed for bankruptcy in 2001 amid mounting asbestos lawsuits.

Coalinga: The City and Its Mines

The area around Coalinga is rife with asbestos deposits. Mining has contaminated the town so badly that the EPA added the city to its Superfund list in 1989. It included an asbestos milling, manufacturing, storage and transportation center. A warehouse, storage yard and shipping yards all handled raw asbestos and asbestos products.

The 120-acre Coalinga Asbestos Mine site switched hands a few times in the 1960s and 1970s, but mining continued there until 1977. Operations ceased when scientists found asbestos in the air, soil, sediments and surface water. The EPA placed it on the National Priorities List. Cleanup ran until 1995, and in 1998, the EPA deleted the mine from the priority list.

Coalinga’s Atlas Asbestos Mine site covered 435 acres and consisted of the asbestos mine, a processing mill and support buildings. The mine operated from 1963 until 1979, and cleanup activities ran from 1994 to 1996. Before cleanup, air, surface water, sediments and soils in the site contained asbestos. What’s left of the Atlas Asbestos Mine site now resides within the Clear Creek Management Area. It is a popular recreation area frequented by thousands of people each year.

The cleanup of the entire city concluded in the 1990s. It involved the removal of an estimated 20,000 cubic yards of asbestos-contaminated material. Results of the EPA’s 2006 review showed that the site was safe and that no further action was necessary.

Clear Creek Management Area

The EPA has also performed testing inside California’s Clear Creek Management Area (CCMA), a 70,000-acre recreational area that is home to one of the largest asbestos deposits in the world.

The CCMA contains a 30,000-acre deposit of serpentine rock — the type of rock in which asbestos forms. According to EPA testing that assessed risks to CCMA visitors, “There was no combination of scenario, toxicity value, or visits per year that were below the EPA acceptable risk range” for asbestos exposure.

EPA air tests indicated that motorcyclists who utilized a certain dirt course inhaled asbestos levels as high as nine times the legal exposure limits. The EPA concluded that “the risks are still extremely high” for asbestos exposure in CCMA.

In August 2011, per the EPA’s recommendation, the Bureau of Land Management ordered the area’s closing during the dry season, when asbestos is most easily disturbed.


About 15 miles to the east of the Clear Creek Management Area and 37 miles northeast of Coalinga is the KCAC mine, which was the last operating asbestos mine in the U.S. when it closed in 2002.

The mine operations began in 1963. It was part of more than 300 claims in the area by the United Carbide Nuclear Company.

King City Asbestos Company purchased the mine in 1985 and continued mining large asbestos deposits for nearly two decades.

The KCAC mine was also the last and longest-operating asbestos mine in the Coalinga area after the Coalinga Asbestos Company Mine closed in 1975 and the Atlas operation ceased in 1979.

El Dorado Hills

Like Coalinga, the California city of El Dorado Hills contains immense amounts of asbestos deposits. In a 2006 report, the U.S. Geological Survey (USGS) stated that asbestos was so prevalent that simple outdoor activities, such as riding a bicycle, raised dust with high concentrations of asbestos. Air samples taken after activities contained 40 times the normal level of asbestos.

The county’s Air Pollution Control District encourages residents to take precautionary measures. El Dorado Hills residents should wet soil before digging to prevent dust from coming up. They remove shoes before entering their homes to prevent tracking in fibrous asbestos. They are also advised to keep doors and windows closed on windy days or during construction.

El Dorado County leaders, together with the local government of California and the federal government, continue to search for ways to protect residents from exposure to the region’s asbestos.

Superfund Sites

The EPA added the South Bay Asbestos Area to the Superfund National Priorities List in 1986. The 550-acre property in Alviso is home to three landfills that received asbestos wastes from a nearby asbestos-cement pipe manufacturing plant. Major cleanups took place in the 1980s and 1990s, and cleanup efforts are currently ongoing according to the EPA.

Some other Superfund sites in California known for asbestos contamination include:

  • Industrial Waste Processing, Fresno
  • Purity Oil Sales, Inc., Fresno
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