In Nevada, a Controversy in the Wind

For the past few years, the geologists Brenda Buck and Rodney Metcalf have combed the wild terrain of southern Nevada, analyzing its stony dunes and rocky outcroppings — and to their dismay, tallying mounting evidence of a landscape filled with asbestos.

Asbestos occurs naturally in many parts of the country, mostly in the West but also along some mountain ranges in the East. But in Nevada, the scientists found, natural erosion and commercial development were sending the fibers into the wind.

Worried about the possible health risks, Dr. Buck and Dr. Metcalf, professors of geoscience at the University of Nevada, Las Vegas, reached out to experts in asbestos-related diseases. With data from Nevada’s cancer registry, an epidemiologist prepared a preliminary report that outlined what she felt was a troubling pattern of mesothelioma — a cancer often related to asbestos exposure — among residents of the affected areas.

But if the scientists expected to be applauded by state officials for their initiative, they were mistaken.

Upon learning of the report, the Nevada Department of Health forced the epidemiologist, Francine Baumann of the University of Hawaii, to withdraw a presentation of the findings at a scientific conference and revoked her access to the state cancer registry. Dr. Metcalf and Dr. Buck offered to meet with state officials but say they were rebuffed.

In the years since, “no one from the health department has ever contacted us to ask for any information about the minerals,” Dr. Metcalf said.

So began one of the country’s more unsettling public health controversies. Over the past several years, the researchers say, they have been vilified for making legitimate scientific inquiries that may have public health consequences. Officials at the state health department counter that the researchers are simply wrong about the asbestos hazard and are promulgating an alarmist hypothesis.

The department’s own analysis has turned up no particular asbestos risks to residents, the officials say, pointing out that the incidence of mesothelioma in the state is well within the national average.

“Asbestos was there for hundreds, if not thousands, of years, and that has not translated into negative health effects,” said Dr. Ihsan Azzam, the state epidemiologist.

Naturally occurring asbestos deposits are not uncommon, and in past decades, particularly rich veins were mined for commercial use. It proved to be a dangerous occupation: Asbestos fibers travel easily through the air and are easily inhaled, scientists later found, embedding themselves in the lungs.

Once there, even in modest amounts, the fibers set off a cascade of inflammatory effects that can lead decades later to lung cancer, mesothelioma and other respiratory ailments. One study conducted a few years ago found that one-fifth of the residents of Libby, Mont., the site of a large vermiculite mining operation, sustained asbestos-related lung diseases. Many never worked in the mines.

The Environmental Protection Agency designated the area a Superfund site in 2002 and, with the Department of Health and Human Services, declared a public health emergency there in 2009.

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