Coast Ranges

The Coast Ranges are a series of mountain ranges running along the Pacific coast of North America from Southern California through Oregon, Washington, and into British Columbia. In the asbestos context, the term most often refers to the California Coast Ranges, where serpentinite and ultramafic rock formations contain naturally occurring chrysotile and tremolite asbestos. These geological deposits supported decades of asbestos mining and milling and continue to produce environmental asbestos exposure today.

Origin

The name reflects the simple geographic description of mountain ranges paralleling the coast, in use since 19th-century U.S. Geological Survey mapping. The geological significance for asbestos was established through 20th-century surveys documenting serpentinite belts along the Coast Range Ophiolite, a fragment of ancient oceanic crust thrust onto the continent.

Significance in Asbestos Context

The California Coast Ranges were the source of much of the asbestos mined domestically in the United States, including operations at the Coalinga, New Idria, and KCAC mines. Rock and soil from these areas (and products made from them, such as crushed serpentine used for road base, landscaping gravel, and stucco aggregate) have been linked to environmental and occupational exposures. For patients with mesothelioma or other asbestos diseases who lived, worked, or played in these regions, the Coast Ranges may represent a non-occupational exposure pathway worth investigating. Provenance analysis of fiber types found in lung tissue (chrysotile vs. tremolite/actinolite) can sometimes connect disease to Coast Range sources versus commercial product exposure.

Example Sentence

Her legal team investigated whether her childhood near serpentine outcrops in the California Coast Ranges contributed to her mesothelioma, in addition to her father's shipyard work.

Related Terms

Serpentinite, Chrysotile, Tremolite, Naturally Occurring Asbestos (NOA), Coalinga, Ophiolite

Notes

• If you lived, worked, or attended school in California Coast Range counties (including Fresno, San Benito, Monterey, Santa Clara, Lake, El Dorado, or Calaveras), document those addresses and dates for your exposure history.
• Ask whether unpaved roads, school yards, or landscaping in your area used local serpentine gravel. This is a recognized non-occupational exposure source.
• Tissue digestion and fiber-burden analysis can identify tremolite or actinolite alongside chrysotile, which may point to a Coast Range geological source rather than commercial products.
• Preserve photographs, property records, and employment records that place you near known mining districts (New Idria, Coalinga) or serpentinite quarries.