The Agency for Toxic Substances and Disease Registry (ATSDR) has released a new report linking the deaths of workers in Libby to the now defunct W.R. Grace vermiculite mine. Not surprisingly, that report reveals that the rate of respiratory deaths is significantly higher there compared to the rest of Montana and the nation.
Although ATSDR released a similar report in December of 2000, it overlooked about 124 worker deaths and was unable to show a causal link between the mine and the deaths. This report, which utilized a database of Grace workers, is the first to show such a link, according to Steve Dearwin, an ATSDR epidemiologist.
According to the database, of the 13 people who died of asbestosis, 12 worked at the Grace mine, and of the three who died of mesothelioma, two worked in the mine. Dearwin also estimates that 16 to 17 percent of those people in Libby who died of lung cancer worked at the mine. Typically, 90 percent of lung cancer deaths are attributable to smoking.
The report, based on the death certificates of more than 500 people, shows that between 1979 and 1998, the death rate from these diseases was 20 to 40 percent higher than in places without such a mine.
Vermiculite mining expels dangerous amounts of asbestos into the air during the blasting process. Asbestosis is 40 to 80 times more common in Libby than elsewhere in Montana and the rest of the nation. Another disease, mesothelioma, was highly elevated, but is such a rare disease that it was difficult to quantify the increase.
Almost all the cases of these two diseases were found in former mine workers, as were many of the cases of lung cancer. All of these diseases are lethal, although some take up to 40 years to kill their victims. Treatment for these diseases costs anywhere from $600 to $800 a month.
For Helen Clark, outreach coordinator for the Libby Asbestos Clinic, it’s obvious that the vermiculite mine is the culprit behind the diseases.
“We have such a high instance [of these diseases] here than is seen anywhere else in the world,” she says.
The mine in Libby is particularly deadly because it has a high content of tremolite, Clark says. Normal asbestos fibers have a rounded, serpentine shape, and when inhaled are less likely to cause damage to the lungs and stomach lining. Tremolite is sharp and spear-shaped, and over the course of 20 or 30 years, cuts through the lungs and stomach, causing their surfaces to be rough and irritated. This irritation, combined with carcinogens in the body, can lead to cancer.
A meeting in Libby is scheduled for Sept. 26 to discuss the report.