In 2009, the U.S. Centers for Disease Control and Prevention (CDC) addressed widespread asbestos contamination in Libby, Montana. Screenings and health care service were provided for those exposed.

The vermiculite mined from Zonolite Mountain is contaminated with asbestos fibers, including the asbestos varieties tremolite and actinolite, and contains the related fibrous minerals winchite, richterite, and ferro-edenite. Collectively, the asbestiform minerals contaminating the vermiculite are referred to as Libby asbestos.

Mining and processing operations, as well as home use of waste rock and products from the mine, resulted in the spreading of Libby asbestos throughout the town. Hundreds of people in Libby, including former mine workers, their families, and other residents, have exhibited signs and symptoms of asbestos-related disease.

Since 1999, in response to reports of widespread disease among Libby residents, EPA’s Region 8 Emergency Response Branch has been conducting sampling and removals to address the most highly contaminated areas in the Libby valley. Since the Libby area was proposed for the NPL in February 2002, these activities are transitioning to EPA’s Superfund Branch for long-term cleanup.

As of November 2018, the U.S. Environmental Protection Agency (EPA) had completed cleanup of over 2,600 properties located within Libby and Troy and had investigated over 7,600 properties within the Superfund site. The EPA has removed more than one million cubic yards of contaminated soil to date.