In a typical news story about a risk of asbestos exposure closing a public facility, the risk is posed by an industrial process or contamination of building supplies. This story is a little different the area closed is a 48-square mile region of central California’s Clear Creek Management Area, and the asbestos risk is posed by the soil itself.
Asbestos is a naturally occurring mineral, but despite its toxicity, environmental asbestos generally poses little or no risk simply because its concentration in the environment is generally very diffuse. Areas like a 31,000-acre segment of the Clear Creek area are different, however, The area is the home of the largest single asbestos deposit on US soil, and is the former site of the Atlas asbestos mine. For years, Bureau of Land Management officials have warned off-roaders, hikers, backpackers, and other visitors to the wildly beautiful region that the area might pose a risk to human health. A recent study, however, indicated that the risk was far greater than had been previously believed, and that as few as five visits to the area could raise lifetime lung cancer risks to those found in workers exposed to industrial-level quantities of asbestos fibers.
For the past three years, the affected area of Clear Creek has been closed during the summer months, the time of greatest dust exposure, while officials from the Environmental Protection Agency conducted an extensive study of the health risks posed by the asbestos. Officials from BLM and the EPA said that dust being added to the air from the more than 35,000 annual visitors many of whom were off-roaders driving motorcycles and SUVs through the regions canyons is a significant reason for the permanent closure. EPA technicians visited the area and engaged in recreational uses typical of visitors to Clear Creek, collecting dust samples with portable pumps at various times of the year. They found chrysotile, tremolite, and actinolite forms of asbestos in concentrations that would be typical for an industrial environment where asbestos was processed or used. Their results were compiled in to a 160-page study which was released in spring of 2008. BLM announced the temporary closure of the 31,000 acres affected by asbestos contamination shortly thereafter. Clear Creek’s remaining 44,000 acres remain open to the public.