In 2009, the Environmental Protection Agency declared a public health emergency in Libby, Montana. More than $575 million was spent on cleaning up tremolite asbestos fibers strewn across the town in the form of vermiculite.
According to EPA studies, thevermiculite mine near the town (which the W.R. Grace Company purchased in 1963 and ran until 1990) spewed some 5,000 pounds of asbestos-laden vermiculite fibers over the town each day. The mined vermiculite (commercially sold as Zonolite) was distributed around town and across the country as soil amendment and insulation for homes and buildings.
Therefore, it wasn’t just the miners who were exposed to asbestos. And, the type of asbestos found in Libby is different — and potentially more dangerous — from that found in other situations. It is called “amphibole” asbestos, as opposed to the more common “chrysotile” type.
When inhaled, chrysotile asbestos fibers corkscrew into the lung tissue. Amphibole asbestos fibers are more like darts, and they lodge into either the outer lining of the lung-a thin, elastic sac known as the pleura. When the pleura is riddled with these tiny asbestos darts, it scars over. The pleura, once as thin as plastic wrap, scars up to be as thick as an orange peel, according to an Associated Press report. This makes it increasingly difficult for the victim to breathe. The process can cause pleural fluid to build up (that is, it can lead to what doctors call pleural effusion) and it can cause pleural mesothelioma.
Tragically, this process can occur after a relatively minor or short-term exposure, and the disease can progress quickly.
“There’s a real misunderstanding that there has to be a long-term occupational exposure,” Black said. “Even low levels can lead to very serious lung disease,” says a doctor working with Libby’s population for over 20 years.
Unfortunately, the tiny darts of amphibole asbestos in a lung’s pleura are much more difficult to detect than the curly chrysotile asbestos. Only experienced pathologists or doctors with specific experience handling amphibole cases like Libby’s can spot the telltale gray shadows on diagnostic tests.
In 2017, doctors in Libby issued a groundbreaking study validating their diagnostic techniques.
The local clinic is still seeing new patients, nearly 20 years after the cleanup. Last year, 837 patients were screened for asbestosis and mesothelioma, and 209 were diagnosed. The clinic’s annual asbestosis/mesothelioma diagnosis rate is about 25 percent — and that includes people who request screenings even though they’re not sick.
The doctors hope that more research can be done on the special problems of amphibole asbestos like that found in Libby. So far, they have not been able to obtain funding.