Case 6: Naturally Occurring Asbestos (NOA) in El Dorado, California: Tremolite Asbestos in Dog's Lung

The health hazards of asbestos are well recognized and documented.

Naturally occurring deposits of asbestos cause no human exposure if left undisturbed below the earth's surface, of course. However, development of areas rich in asbestos fibers can cause asbestos fibers to be released into the air, resulting in potential exposures to those humans and animals breathing that air.

Such 'environmental' exposures and their major health consequences are well documented in the scientific literature.

Using animals resident in areas of NOA as 'bio-sensors' for such asbestos exposure has been reported.

A dog residing in a home built on exposed tremolite asbestos deposits in an area of NOA (El Dorado, California) from age 1 to 9 years died in 2003, at age 13 years, and his lungs were examined using light microscopy and electron microscopy. The results confirmed extremely high concentrations of asbestos fibers in his lungs.

[Mr. Terry Trent's encouragement and assistance with this investigation has been greatly appreciated, and Bryan Burnett (Meixa Tech) has done much additional SEM/EDS analysis.]

The initial summary of the data was prepared for presentation in PowerPoint format at the EPA-sponsored conference on August 18, 2004, but EPA decided on August 16, 2004 not to permit our presentation.

It is highly likely that substantial human exposures from such developments in this area and similar areas have already occurred, and the disease burden with long latency of several decades is only beginning.

It would seem essential for Public Health to take whatever steps possible to STOP further exposures as much as possible so as to minimize the health impacts. For example, any existing and further development of roads, schools, housing etc. on such sites with exposed NOA tremolite and other types of asbestos should be carefully evaluated.