Once airborne, naturally occurring asbestos fibers can float on air currents for days or weeks. When the tiny, needle-like fibers are inhaled, they pierce the lungs and surrounding tissue.
The fibers can scar the lungs, making it hard to breathe a condition called asbestosis. Fibers embedded in lung airways can also cause lung cancer. Asbestos fibers that slice through the lungs and into the chest cavity lining injure mesothelial cells and cause cancerous tumors. Mesothelioma is a fairly rare cancer that can take 25 to 40 years to develop, yet it kills nearly all its victims within a year of diagnosis.
Because asbestos-caused illnesses take so long to develop up to 40 years for the rare and deadly mesothelioma it is difficult to track the health consequences of exposure.
And efforts to more-strongly regulate naturally occurring asbestos have met mixed results.
The long-range public health consequences of naturally occurring asbestos are a mystery as deep as the Asbestos Monofill off O'Byrnes Ferry Road in Copperopolis, a massive pit near Tulloch Reservoir that was once considered the largest asbestos-producing mine in the United States.
Since public health departments are concerned with acute, communicable disease such as flu or E. coli, they do not receive reports concerning asbestos.
The state's Cancer Surveillance Program keeps statistics on mesothelioma in mountain counties. Monica Brown, regional cancer epidemiologist with the program, said, because mesothelioma is so rare and mountain counties have such small populations, the case numbers are kept in five-year-increments.
"Typically we see this cancer in older men who have worked either directly with asbestos or in industries using asbestos-related products (such as pipe fitters)," she said. "We have no way of assessing environmental exposure. Our numbers are based on cases as they are diagnosed or by death certificates."
Brown said statistics for Alpine, Amador and Calaveras counties are combined because of the counties' small populations. Between 1999 and 2003, nine cases were reported, and most recently, between 2000 and 2004, seven cases were reported, she said.
"The cases are dwindling and this is to be expected because employers have gotten better at protecting people from occupational exposure," she said.
She said the numbers for Alpine, Amador and Calaveras counties are too small to draw any conclusions or make any comparisons with more populous areas. Unlike smoking and lung cancer, Brown said, there is no straight correlation between exposure to asbestos and development of mesothelioma.
"We can't tell you for sure what your risk is for developing cancer from exposure to asbestos," she said. "EPA measures risks of exposure but we can't translate that into expected cases of mesothelioma."
At a 2005 state Senate hearing on naturally occurring asbestos hazards, Dr. Michael Lipsett, physician-epidemiologist with the Environmental Health Investigations Branch of the Department of Health Services, said that a number of studies link naturally occurring asbestos with elevated rates of mesothelioma.
"So in the context of these observations, residential development in areas where there are large surface deposits of asbestos raises important issues of public health," he said.
Lessons learned at school
Alex DeWitt, a senior geologist for Sonora-based Condor Earth Technologies, which does soil testing for schools and other clients, says schools are leading the way in taking precautions against asbestos contamination because they are required to test before construction begins, while other developers are only required to keep dust down after the grading and trenching has already started.
"Once the regulator agencies have actually come up with specific numbers for health effects, they can develop regulations and then they'll be put into effect for developers," Dewitt said.
He estimates that such regulations will be developed within the next five years.
In 2005, the state Senate Health Committee and Senate Environmental Quality Committee conducted an informational hearing: "Naturally Occurring Asbestos: Who is Responsible for Protecting the Public Health?"
Toxicologists and physicians, including Lipsett, testified that naturally occurring asbestos, once airborne, can cause cancer.
As a result of the hearing, then-state Sen. Deborah Ortiz, D-Sacramento, introduced Senate Bill 655 which would have, among other things, required local governments when amending their General Plans to incorporate provisions for mitigating areas of asbestos. The bill passed in the Senate 27-11 but was rejected by the Assembly 35-42 in September 2005.
Sen. Dave Cox, who represents Calaveras County, voted against the bill, as did Dave Cogdill, who was assemblyman for both Calaveras and Tuolumne counties and now represents Tuolumne County as a state senator.
Ortiz has left state government because of terms limits.
Rachel Machi, consultant with the California Senate Health Committee, said there is no indication of interest among other senators in picking up the bill.
"Nothing is going on with the legislation," she said. "There is no new bill being written that I know of."
Among the groups opposing the bill were California Building Industry Association, the California Business Properties Association, the California Chamber of Commerce, California Major Builders Council and the California Business Roundtable.
Two main reasons stated for SB 655's defeat were that the bill lacked funding for its required state-level asbestos task force and for its mandated mapping of the state's asbestos-bearing rocks. Despite the failure of SB 655, Dewitt believes strongly that "regulations are coming." Calaveras County Planning Director Robert Sellman agrees. "We're looking at all these things that have been lightly treated in the past. If we have school districts facing it, we know it is an issue," he said.
"As the General Plan is updated, we'll research what's required," he said. "The whole purpose of the General Plan is to look at health, safety and general welfare as development occurs, so it's an issue we recognize as significant and we'll look at it."
Past chairwoman of the Calaveras County Board of Supervisors Merita Callaway said the county requires developers to check the soil to see if it's compatible for septic systems before putting in such systems, and that perhaps some such protocol could be developed for naturally occurring asbestos.
"I'm hopeful that the county will take some kind of action," she said. "Whether it's in the General Plan or in our building codes is not as important to me as the fact that we do something."
Tuolumne County Board of Supervisors Chairman Mark Thornton said in his 10 years on the board, the topic had never been discussed at length.
"I think that's because we've addressed it," he said. "The county has mapped the areas where asbestos may exist. We have measures in place dust abatement measures and others that ensure the health of the public."
What's being done elsewhere
El Dorado County officials have adopted strict rules prohibiting dust plumes higher than 25 feet and requiring developers to document exactly where excavated soil goes. If it goes off-site, it must be tested for asbestos.
All development sites within a quarter-mile of areas expected or found to have asbestos must post warning signs at project entrance points.
And the county has held a series of workshops for contractors and developers to inform them about the latest dust-containment requirements and the best practices to use to meet them.
All of this regulation results from EPA studies that found dangerous levels of natura
lly occurring asbestos in the air of several county neighborhoods, including school sites. Sellman thinks Calaveras and other affected counties may have to borrow from some lessons learned in El Dorado County.
"I think we're going to have to look at the issue. Absolutely. What that means I can't tell you yet," he said. "Presumably we're going to try and learn from neighboring counties who have grappled with the problem and see what has worked and what hasn't."