Written by Michelle Whitmer | Scientifically Reviewed By Arti Shukla, Ph.D. | Edited By Walter Pacheco | Last Update: April 24, 2024

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.

Zonolite storage in Libby, Montana
The asbestos-contaminated mines in Libby, Montana, have been responsible for hundreds of deaths and thousands of illnesses.

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. 

Cleanup Efforts Span Decades

Cleanup in Libby is the largest, longest-running asbestos cleanup project in American history. It began slowly at first as workers from the U.S. Environmental Protection Agency identified the sources of contamination and began an extensive Superfund investigation.

Cloud of Dust at Zonolite Mill
Toxic asbestos dust filled the air when the Zonolite mines were operating in Libby, Montana.

It was unlike any project the agency had ever seen. Libby homes and businesses needed asbestos-contaminated vermiculite removal, and the mine site needed attention to prevent further issues. Contamination of natural resources demanded a large-scale investigation as well. Libby was finally placed on the EPA’s Superfund list in 2002.

In 2008, W.R. Grace was ordered to provide $250 million to cover future cleanup costs. By 2018, the agency’s cleanup efforts finally began to wind down.

In 2023, Grace agreed to an $18.5 million settlement to restore damaged lands in and around the Superfund site.

The EPA investigated more than 8,200 properties and completed cleanups at more than 2,600 sites, including businesses, yards, homes, parks and other contaminated areas.

Over a million cubic yards of dirt and building materials were removed and replaced. More than $600 million of federal money was spent during the decontamination efforts.

Aerial view of the mines in Libby, Montana
The old Zonolite mine in Libby, Montana, remains under EPA oversight to this day.

In September 2021, the agency announced that another major section of the sprawling restoration effort had been completed. The area was identified as Operable Unit 8 and included all roadways and major highways in and between Libby and Troy.

The agency transferred oversight and responsibility for much of the project to the Montana Department of Environmental Quality on July 1, 2020. Only the actual mine site remains under the EPA’s oversight.

History of the Libby Tragedy

Vermiculite mining in Libby began when E.N. Alley bought the Rainy Creek mining claims in 1919 and launched Zonolite Company. In 1963, Maryland-based W.R. Grace & Company acquired Alley’s Zonolite business. By this time, vermiculite had been mined for more than 40 years approximately seven miles outside of Libby.

Before Grace took over ownership of the mine, employees had developed lung problems and several fatalities were reported. Despite these health issues, the company claimed it was “unaware of the hazards of mining and milling vermiculite” when it purchased the business.

Evidence revealed in court showed W.R. Grace executives knew about the mine’s high level of tremolite asbestos dust and that exposure to the dust was damaging to the lungs, yet they never said anything to their employees.

little league game in Libby, Montana
Asbestos-tainted vermiculite was used around town in Libby, Montana, including on the baseball fields and playgrounds.

Townspeople were also affected by the asbestos-tainted vermiculite because Grace distributed its leftover vermiculite for use in playgrounds, backyards, gardens, roads, driveways and other popular locations in the town.

While asbestos was circulating in the air around the mine, it also was found in baseball fields and other areas where children and citizens commonly spent their time.

In 2003, researchers determined the vermiculite was contaminated with one regulated and two unregulated forms of amphibole asbestos. 

Tremolite is the regulated form, which is considered highly carcinogenic and made up 6% of the ore. The two unregulated types were winchite and richterite, which made up 84% and 11% of the ore, respectively. Collectively, they’ve been referred to as Libby amphiboles.

Researchers believe Libby amphiboles have led to some residents developing a type of pleural disease called lamellar pleural thickening, which is pleural thickening that develops parallel to the ribs.

By 2010, physicians at the Center for Asbestos Related Disease had diagnosed asbestos-related pleuropulmonary disease in 1,883 people, which was 47% of the 4,028 people who had received screenings. By 2022, the center had diagnosed more than 2,400 residents around Libby with asbestos-related diseases.

Libby Asbestos Lawsuits & Settlements

Thousands of Libby residents and former W.R. Grace & Company mine workers have filed lawsuits against Montana state agencies for failure to warn them of the dangerous asbestos contaminating the vermiculite mine. Several major group payouts have compensated affected Libby residents.

Individual lawsuits against insurers began reaching resolution in 2022. Claims against insurers became possible after a Montana Supreme Court decision in March 2020 ruled insurers are no longer protected by W.R. Grace’s bankruptcy plan, which it filed in 2001.

  • In February 2022, a Montana jury ordered Maryland Casualty Company to pay $35.5 million to Ralph Hutt, who developed asbestosis from working in the Libby mine for just 18 months in the late 1960s. Maryland Casualty was the insurance carrier overseeing the occupational safety program at W.R. Grace. The award included $6.5 million in compensatory damages and $30 million in punitive damages. Hutt’s was the first of more than 900 similar lawsuits pending against the company.
  • A major group payout came in January 2017, when more than 1,000 Libby victims were awarded a $25 million settlement. The settlement resolved more than 100 individual lawsuits involving multiple claimants. The lawsuits targeted Montana state agencies that failed to warn Libby residents about the mine’s dangers.
  • In September 2011, a district court judge ordered the state of Montana to pay a $43 million settlement to more than 1,300 Libby plaintiffs. An estimated 200 of those plaintiffs began receiving their portion of the settlement in 2012, more than a decade after the first lawsuit was filed.
  • In August 2014, the W.R. Grace asbestos trust fund, known as the WRG Asbestos PI Trust, began accepting claims from Libby residents and many others who were injured by Zonolite products contaminated with asbestos. In its second year of operation, the trust paid $353 million to resolve more than 50,000 claims.
  • Between 2000 and 2009, 800 Libby residents filed claims against W.R Grace. Many of them were filed while the company was working through bankruptcy proceedings. Before it filed for bankruptcy in 2001, Grace was sued by approximately 150 Libby residents. Six of those cases when to trial, while most of the rest were privately settled.

Montana agencies continue to claim that the state had no legal obligation to provide warning of the mine’s dangers.

Today, Libby is considered safe by the U.S. Environmental Protection Agency. According to the agency, the amount of asbestos in downtown Libby is now nearly 100,000 times lower than when the mine was operating.

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