Asbestos Risk Closes Central California's Clear Creek Area

HOLLISTER, California, May 1, 2008 (ENS) – People enjoying recreational activities at the Clear Creek Management Area in central California may not realize it but they are exposing themselves to high levels of asbestos in the soil, which increases their risk of developing cancer.

Based on the findings of a new study of asbestos exposure risk to visitors released Wednesday by the U.S. Environmental Protection Agency, the Bureau of Land Management today issued an immediate temporary closure of 31,000 acres, a little less than half of the area.

The area in southern San Benito and western Fresno counties contains the largest deposit in the United States of asbestos, a known human carcinogen.

The Clear Creek Management Area hosts about 35,000 visitors a year – hikers, campers, hunters, botanists, rock collectors, and off-highway vehicle riders, including many families with children.

Vehicles traveling through the Clear Creek
Management Area raise
asbestos-laden dust.
(Photo courtesy EPA)

The EPA study found that riding motorcycles and all-terrain vehicles and driving SUVs creates the highest asbestos exposures by stirring up the naturally occurring asbestos in the soil. These riders and drivers are exposed to asbestos in the range seen in industrial environments, the study found.

“The EPA’s sampling results demonstrate that in areas where asbestos is present in the soil, activities that create dust also create asbestos exposure,” said EPA toxicologist Daniel Stralka, PhD.

“Higher dust-generating activities produce higher exposures and, therefore, higher risks,” he said.

Based on the asbestos exposure levels, the EPA estimated lifetime excess cancer risks. Many activities in the Clear Creek Management Area, CCMA, were found to have risks above the range that EPA considers to be acceptable.

The EPA data showed that children are generally exposed to higher asbestos concentrations than adults participating in the same activities.

In 2004 and 2005, EPA Region 9 collected air samples while EPA employees and contractors participated in typical recreational activities common to the CCMA.

The samples were collected from the breathing zone of individuals riding motorcycles and all-terrain vehicles, driving and riding in SUVs, hiking, camping, sleeping in a tent, fence building, and washing and vacuuming vehicles after use at the CCMA.

“The asbestos levels measured in the breathing zone at CCMA are in the range seen in industrial environments and are at levels of concern, said Stralka. “Reducing or eliminating dust-generating activities in CCMA will reduce exposure and reduce the risk of developing asbestos-related disease.”

The EPA risk assessment only evaluated excess lifetime cancer risks. Asbestos can also cause debilitating and fatal diseases other than cancer, such as asbestosis and pleural disease.

The EPA risk assessment did not take other diseases into account because no asbestos toxicity values exist for non-cancer health effects, Stralka said, adding, “Non-cancer health effects from heightened asbestos exposure in the area may actually be more significant to total disease outcome than cancer.”

The Clear Creek Management Area spans more than 75,000 acres across San Benito and Fresno Counties and includes the Atlas Asbestos Mine Superfund Site. It includes a 31,000 acre outcrop of naturally occurring asbestos.

Most of the area is managed by the federal Bureau of Land Management. Both BLM and the EPA have advised users of the asbestos health hazard existing at the area since the early 1990s.

Now, BLM staffers will use the information provided in the EPA’s risk assessment to evaluate alternatives in an upcoming environmental impact statement for managing the Clear Creek Management Area.

BLM’s Hollister field manager Rick Cooper said protecting the public’s health and safety is the agency’s first priority. “Based on EPA’s results, we believe a temporary closure of most of the CCMA is in the public interest and we ask for the public’s cooperation.”

“With the closure in place, we will immediately move on with developing a long-term resource management plan for the area with the public’s full involvement,” said Cooper.

BLM will continue public scoping started last year for the resource management plan through June 21, 2008. Two public workshops – May 19 in Hollister and May 21 in San Jose – to discuss the planning process have been scheduled.

The BLM also is hosting an informational meeting May 8 at the Convention Center in Santa Clara for EPA representatives to present assessment findings with the public.

Cooper said the BLM will work closely with interested parties to develop management actions best suited to the resources and the needs of the public, taking into account local, regional, and national concerns.

“Early participation by all interested parties is encouraged and will help guide the planning process and determine the future management of public lands,” he said.

For further information contact the BLM in Hollister by phone at: 831-630-5000 or by e-mail,

To view the EPA Asbestos study, click here [].

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