California Mesothelioma: 284 Cases, Most in the US (2021)

California’s mesothelioma burden is the largest of any state by raw numbers. With 284 new cases confirmed in 2021 by CDC primary data, the state accounts for more diagnoses than any other in the nation. The reasons are both industrial and geological: a century of shipyard, refinery, and construction exposure combined with naturally occurring asbestos deposits spanning 42 of the state’s 58 counties.

The scale of the problem is visible in the death toll. Between 1999 and 2022, 5,748 people in California died from mesothelioma. Thousands more died from asbestosis, lung cancer, and other asbestos-related diseases. Every major metro area is affected, and the exposure pathways are still active in buildings, soil, and infrastructure built before the 1980s.

State Rankings

For a full comparison of all 50 states, see our mesothelioma rates by state rankings.

County-Level Data

Los Angeles County leads the state in mesothelioma burden. A century of industrial activity at the San Pedro shipyards, Long Beach Naval Shipyard, the refineries along the 710 corridor, and the massive postwar construction boom built asbestos exposure into virtually every commercial building in the region.

Contra Costa County’s elevated death toll is driven almost entirely by the concentration of oil refineries along the Carquinez Strait. Chevron, Shell, and other operators ran facilities where asbestos insulation was standard on pipes, boilers, and processing equipment for decades. The Bay Area counties and San Diego metro area also show elevated rates from shipyard, refinery, and military exposure.

Where Exposure Happened

California’s asbestos burden traces to four primary sources.

Shipyards

San Francisco’s Hunters Point Naval Shipyard, the Mare Island Naval Shipyard in Vallejo, and the Long Beach Naval Shipyard were among the busiest military shipyards on the West Coast. Tens of thousands of workers built, maintained, and decommissioned vessels in enclosed environments where asbestos was present in insulation, pipe covering, boiler lagging, and fireproofing. Hunters Point remains a Superfund site. Similar shipyard exposure drove elevated rates at the Brooklyn Navy Yard in New York, the Jacksonville and Pensacola yards in Florida, and the Savannah port facilities in Georgia.

Oil Refineries

The Bay Area’s refinery corridor, stretching from Richmond through Martinez and Benicia, and the refineries in the LA Basin and Long Beach used asbestos insulation extensively. Pipefitters, boilermakers, and maintenance workers who kept these facilities running were exposed to asbestos fibers throughout their careers.

Naturally Occurring Asbestos

California is one of the few states where asbestos occurs naturally in the geological formations. The mineral has been identified in 42 of 58 counties, with concentrations in the Sierra Nevada foothills, the Coast Ranges, and parts of Southern California. Construction, road building, and land grading in these areas can disturb asbestos-bearing rock and release fibers into the air.

Construction and Military

The postwar building boom in Southern California used asbestos-containing materials in virtually every commercial and residential structure built between the 1940s and 1980s. Military installations, from Camp Pendleton to Travis Air Force Base, added another layer of occupational exposure for service members and civilian workers.

Who Is Most at Risk

• Shipyard workers at Hunters Point, Mare Island, Long Beach, and San Pedro
• Oil refinery workers in the Bay Area and LA Basin
• Construction tradespeople working in pre-1980 buildings statewide
• Military veterans stationed at California bases and shipyards, who face elevated risk across all service branches
• Pipefitters and insulators across all industrial sectors, one of the highest-risk occupational groups nationally
• Residents near natural asbestos deposits in the Sierra Nevada foothills and Coast Ranges

Consistent with the 20 to 60-year latency period between exposure and diagnosis, the majority of California mesothelioma deaths occur in people aged 60 and older. Nationally, the overwhelming majority of cases and deaths are concentrated in individuals aged 65 and older, a pattern confirmed across CDC and NCI data sets.

Legal Landscape

For an overview of all current treatment options, see the 2026 mesothelioma treatment landscape. California’s asbestos trust fund claims are relevant across all exposure industries. Shipyard workers, refinery workers, and construction tradespeople were exposed to products from dozens of manufacturers, many of which have established bankruptcy trusts that still accept claims.

Verdicts and settlements in California reflect both the state’s industrial diversity and its plaintiff-favorable legal environment, with some of the largest mesothelioma awards in the country originating from California courts.