Shipyards, Refineries, and Geology: California Asbestos Exposure Legacy

California’s position as the state with the highest total mesothelioma case count traces to a combination of industrial and geological factors found nowhere else in the country. Three primary exposure pathways, military shipyards, oil refineries, and naturally occurring asbestos deposits, created overlapping zones of risk that reach from San Francisco Bay to the Mojave Desert.

The workers who built the ships, maintained the refineries, and constructed the buildings are the ones receiving diagnoses now, decades after their last shift. And in 42 counties, the asbestos is still in the ground.

The Shipyard Corridor

Hunters Point Naval Shipyard, San Francisco

Hunters Point operated as a naval shipyard from 1941 to 1974, building and repairing hundreds of vessels during World War II, the Korean War, and the Vietnam War. The shipyard employed thousands of workers in enclosed dry docks and below-deck compartments where asbestos was omnipresent.

Every ship that passed through Hunters Point contained asbestos in pipe insulation, boiler lagging, turbine gaskets, fireproofing, and electrical insulation. Workers who removed old insulation and installed new material breathed concentrated fibers throughout their shifts. The Navy’s own records document the extent of asbestos use across its fleet.

Hunters Point was placed on the EPA’s Superfund National Priorities List. Cleanup has been underway for decades, complicated by the discovery that contamination is more extensive than initial assessments indicated.

Mare Island Naval Shipyard, Vallejo

Mare Island, the first naval shipyard on the Pacific Coast, operated from 1854 to 1996. The facility built and maintained submarines, destroyers, and other vessels throughout its 142-year history. Asbestos exposure at Mare Island followed the same pattern as other naval shipyards: insulation, pipe covering, boiler work, and fireproofing in confined spaces.

Workers at Mare Island face the additional complexity of overlapping exposure periods. A worker who spent 20 years at the shipyard was exposed to multiple generations of asbestos-containing products from different manufacturers, which expands the number of trust fund claims available.

Long Beach Naval Shipyard

The Long Beach Naval Shipyard was one of the largest on the West Coast, employing more than 17,000 workers at peak operations. The facility repaired and overhauled aircraft carriers, battleships, cruisers, and submarines. Like Hunters Point and Mare Island, asbestos was integral to every ship system.

Long Beach closed in 1997, but the workers who served there are still being diagnosed with mesothelioma. The shipyard’s size and the volume of work performed there mean a large population was exposed over many decades. The same below-deck conditions that made West Coast shipyard work so dangerous were present at the Brooklyn Navy Yard in New York, the Savannah port in Georgia, and the Jacksonville yards in Florida.

The Refinery Corridor

Bay Area Refineries

The Carquinez Strait corridor, running from Richmond through Martinez, Rodeo, and Benicia, contains one of the largest concentrations of oil refineries in the country. Chevron, Shell, Tesoro, and Phillips 66 all operate or operated major facilities in this stretch.

Oil refineries used asbestos insulation on every pipe, vessel, and piece of equipment that handled high temperatures. Pipefitters, boilermakers, and insulators who maintained these systems were in constant contact with asbestos-containing materials. The work was continuous: turnarounds, maintenance shutdowns, and routine repairs meant asbestos was being cut, stripped, and replaced year-round.

Contra Costa County’s 1,198 asbestos-related deaths are a direct reflection of this refinery concentration.

LA Basin Refineries

The refineries along the 710 corridor in Carson, Wilmington, and Torrance added another major exposure zone. El Segundo’s Chevron refinery, the largest on the West Coast, employed thousands of maintenance workers who handled asbestos insulation throughout their careers.

Naturally Occurring Asbestos

California’s geological formations contain naturally occurring asbestos in 42 of 58 counties. The mineral is found in serpentinite rock formations concentrated in the Sierra Nevada foothills, the Coast Ranges, and parts of Southern California.

Unlike occupational exposure, which ended when industries changed practices, natural asbestos remains in the ground permanently. Activities that disturb the soil, including construction, road building, grading, and even off-road recreation, can release fibers into the air.

The California Air Resources Board adopted regulations in 2002 requiring dust control measures during construction and grading in areas with naturally occurring asbestos. However, enforcement varies by county, and many residential properties sit on or near asbestos-bearing formations.

High-Risk Areas

• El Dorado County. One of the highest concentrations of naturally occurring asbestos in the state. Residential development in the foothills has raised concerns about exposure during construction.
• Amador, Calaveras, and Tuolumne counties. Sierra Nevada foothill communities with documented natural asbestos deposits.
• Lake County. Home to the Clear Creek Management Area, a former asbestos mine and one of the largest natural asbestos deposits in the country.
• San Benito County. The New Idria asbestos mine, one of the largest in California, operated until the 1970s. Contamination persists in the surrounding area.

Military Installations

Beyond the shipyards, California’s military bases added another layer of exposure. Camp Pendleton, Travis Air Force Base, Edwards Air Force Base, Fort Irwin, and dozens of other installations used asbestos-containing materials in buildings, infrastructure, and equipment. Service members and civilian workers at these facilities face the same latency-delayed risk. Across all branches, veterans account for roughly one in three mesothelioma cases nationally.

Take-Home Exposure

Shipyard workers, refinery workers, and construction tradespeople carried asbestos fibers home on their clothing, hair, and skin. Spouses who laundered contaminated work clothes and children who had contact with returning workers were exposed to the same fibers.

California courts have recognized take-home exposure as a valid basis for claims. In January 2026, the Virginia Supreme Court ruled that shipyard employers owe a duty of care to workers’ family members exposed through contaminated clothing, a decision that strengthened the legal foundation for secondary exposure claims nationwide. Families affected by secondhand exposure may have both lawsuit and trust fund options.