In El Dorado Hills' upscale Serrano community, a proposal to build 135 homes on a ridge bearing asbestos veins has raised neighborhood opposition along with difficult questions about the health risks of living near the fibrous minerals. Here's a primer on what scientists know – or don't know.
Does living in an area known to contain asbestos deposits increase the risk of lung disease?
Not necessarily. Locked in the Earth, the minerals pose no danger. But blasting, drilling, earth-moving and grading can disperse the minerals' fibers, especially in dry soil. The potential risk increases with the duration and intensity of exposure to the breathable fibers.
Why worry about asbestos in El Dorado Hills, when the fibers are known to be present in the air practically everywhere – the result of natural weathering and its widespread use in automotive brakes?
Western El Dorado County probably has more home and road construction churning up asbestos near residents than any other area of California, according to U.S. Environmental Protection Agency officials. Excavation work and even recreational activity in fields and trails with asbestos-containing soil can significantly increase an individual's exposure above the normal levels in the air, EPA studies show.
Can't the inhaled fibers be coughed up like dust?
Certain asbestos fibers can bypass the defenses and lodge deep into the lungs for life to cause cancer. Areas within and near the proposed Serrano development contain a type of asbestos called amphibole that is far less likely to dissolve in the lungs over time than the more common, commercially used chrysotile asbestos.
Doesn't it take years of asbestos exposure to develop lung disease?
Not necessarily for amphibole asbestos. Brief, episodic exposures – weeks, not years – are enough to trigger lung disease decades later. The "biopersistence" of these fibers is one of the characteristics that make them at least 100 times more potent than the commercial variety in causing mesothelioma, an inoperable and almost always fatal cancer of the membranes lining the chest and other body cavities.
Has anyone died or gotten sick from breathing asbestos released from construction activity in the El Dorado Hills area?
Health experts don't know. No one has studied it. The California Cancer Registry, which tracks cancer deaths, can't tell where or how a victim was exposed. Further, it typically takes 20 to 30 years from the time of initial exposure for mesothelioma to take hold. Victims who had moved away during that long latency would not be included in the county statistics.
Will the county-required asbestos dust controls adequately protect residents near construction sites?
No one has studied the question, according to Jack Momperler, an air pollution officials who enforces the asbestos controls at work sites in Sacramento County. The primary control – watering the site – has proved effective in demolition of old buildings that contain asbestos fireproofing and insulation, he said. But, unlike the hollow chrysotile fibers in building materials, the amphibole asbestos does not absorb water – so spraying would be less effective, Momperler said.
Call The Bee's Chris Bowman, (916) 321-1069.
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