Mesothelioma threat in California rock formations

California holds some of the largest US deposits of asbestos, a naturally occurring substance found in rock formations and used heavily around the world in manufacturing, industry and construction. Praised through most of the last century as the “backbone of American industry,” asbestos quickly lost its positive reputation as associated health hazards began to be noted and studied.

Although fire resistant and durable, making it a sought after building material, asbestos causes several severe respiratory illnesses, including rare and fatal cancer, mesothelioma. The more was learned about the dangers of asbestos, the less it was used in US, UK, Australia and other countries. However, for many populations much damage had already been done. Thousand of people exposed to asbestos in the nineteen hundreds are now being diagnosed with mesothelioma.

Mesothelioma is characterized by a long latency period, making it difficult to diagnose and almost impossible to detect early. While asbestos was being used for much of the industries worldwide, its health effects went unnoticed for decades. Now, mesothelioma cases continue to show up as many as fifty years after asbestos exposure.

California asbestos deposits have raised concerns for many. San Benito and Fresno counties share an area popular for off-roading and other outdoor activities. This Clear Creek Management Area holds many rock formations containing asbestos. Dust and dirt kicked up and circulated by motorcycles, all-terrain-vehicles, and other vehicles could cause a toxic level of airborne asbestos fibers.

Once asbestos fibers are inhaled they can become lodged in lung lining tissue and begin the cancerous process of mesothelioma development. Malignant mesothelioma spreads through affected areas in an irregular web like fashion.

Mesothelioma treatments include surgeries, chemotherapy, and radiation therapy; most often administered in combination as palliative care. There is no cure for mesothelioma. Treatments typically focus on extending patient life expectancy and raising quality of life.

According to a Los Angeles Times report, Environmental Protection Agency considers the level of asbestos in the dust of Clear Creek Management Area unsafe for all visitors. The location sees over thirty thousand visitors a year, making the threat a large one when considering the possible number of people who could be exposed. The area has been closed for several years.


As part of a federal response to this situation, US Geological Survey has just released a map including all known asbestos deposits in this area and throughout California. Authorities and area administrators continue to consider how best to handle the potential danger.