Health Library

Published: October 2022

Libby Asbestos

Published By:

Contributors: Michelle Whitmer


How Did Asbestos Contaminate Libby?

The story traces back to 1919 when companies first started mining vermiculite ore in Libby, Montana.

Vermiculite is a naturally occurring mineral with heat-resistant properties. Vermiculite and asbestos form under similar conditions. The two minerals sometimes develop alongside each other, and asbestos contaminated Libby’s vermiculite deposit.

Libby vermiculite, known commercially as Zonolite, was used in a variety of construction materials, including insulation for homes and buildings. Decades of mining exposed workers and residents of Libby and Troy, a nearby town, to toxic asbestos dust.

When W.R. Grace & Company took over operation of the mines in 1963, it knew the vermiculite was contaminated with asbestos and that it caused health complications. The company didn’t warn anyone about the asbestos exposure, and mining continued until 1990.

An estimated 694 Libby residents have died of asbestos-related diseases, according to a 2021 study published in the Journal of Exposure Science and Environmental Epidemiology. The study also reported a 15-fold increased risk of mesothelioma among W.R Grace workers compared to residents who didn’t work around the mine.

At least 1 in 10 people in Libby currently have an asbestos-related illness, according to the Center for Asbestos Related Disease in Libby. In addition to the hundreds of residents who have died, approximately 2,400 have been diagnosed with asbestos-related diseases since the contamination began.

The Seattle Post-Intelligencer newspaper ran a series of articles about Libby in 1999 that gained national attention. The U.S. Environmental Protection Agency stepped in that year and began to clean up the town in 2000.

In 2009, the agency declared a public health emergency in Libby and called it the worst case of industrial poisoning of a community in U.S. history. It was the first and only time the agency announced a public health emergency, which provided extra funding for health care for residents.

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