A new study of adults who lived in Libby, Montana, as children and were exposed to low levels of amphibole asbestos were found to have elevated levels of pleural thickening, according to findings of a study just published in the American Journal of Industrial Medicine. While we have discussed asbestos-caused mesothelioma, cancer of the pleura or lining around the lungs, this study measured asbestos-related thickening of the pleura through scar tissue that can cause breathlessness.
While pleural thickening is not cancerous, it restricts the lungs as they try to expand, leaving the person unable to take a deep enough breath, especially with exertion.
For decades, the Zonolite Company, followed by W.R. Grace, mined vermiculite in Libby that was contaminated with asbestos. The U.S. Environmental Protection Agency included the site on the Superfund National Priorities List in 2002, followed by a Public Health Emergency declaration in 2009, triggering federal health care for those in Libby harmed by asbestos.
The EPA has removed significant amounts of the asbestos from the environment, but cleanup is ongoing.
In addition to industrial exposure by miners, the contaminated vermiculite was used throughout the community in areas where children played and citizens conducted normal activities, like ball fields, parks and gardens. Because many Libby residents may have been exposed as children and teens, studies are ongoing over their potential to develop asbestos-related diseases, like the one just published about pleural thickening.
The New Study Findings
Researchers from Idaho State University, the Icahn School of Medicine at Mount Sinai, the University of Montana and the Center for Asbestos Related Diseases studied chest CT scans of 198 people who were children or adolescents in Libby, but later left the area.
Almost half of the 198 subjects (96 people or 48 percent) had pleural thickening. Of these, 25 had calcification. The 48 percent number is significant as compared to lower levels found in earlier studies of people with no industrial exposure to asbestos (.2 to 6.5 percent in people with no or just possible asbestos exposure; 20 percent in people with “probable/confirmed exposure” and a high of 41 percent in one other cited study).
The chances of developing pleural thickening increased with the length of time the person lived in Libby, and men were three times more likely to develop the condition than women.
Anyone concerned about asbestos-related disease from any source should seek legal advice.