"Karstolite" Insulation and Other Karst Mine Asbestos

Click Here To Download Karstolite Asbestos Brochure in PDF format

What is Karstolite?

Karstolite is a brand name for the asbestos insulation originating from the Karst Mine near Big Sky, Montana.


Karstolite Insulation In Attic
Karstolite Insulation In Attic

Karst Mine Asbestos

The type of asbestos mined at the Karst Mine is called Anthophyllite, one of a group of naturally occurring fibrous minerals considered to be asbestos.


Asbestos ore from the Karst Mine
Asbestos ore (anthophyllite) from the Karst Mine

Where Is It Found?

Accurate recognition, reporting, and handling of materials that potentially contain asbestos is the best way to prevent exposures and related health consequences.

Milled anthophyllite asbestos was used as insulation in an undetermined number of buildings in the Bozeman, Livingston, and Helena areas. Milled anthophyllite asbestos can appear like one or a combination of the following descriptions:

  • Dirty cottage cheese
  • Fibrous, shiny chunks
  • Khaki, brown or gray-colored, fibrous and/or fine powder

Asbestos insulation may not be easy to recognize if it is covered with other types of more recently installed insulation material.


Karstolite (anthophyllite) Insulation
"Karstolite" (anthophyllite) Insulation

How Does Karstolite Differ From Libby's Zonolite (Vermiculite) Insulation?

Karstolite Insulation Bag Zonolite from Libby
Karstolite Insulation Bag
Zonolite Insulation From Libby

Another type of insulation commonly used in Montana was “Zonolite”. This vermiculite insulation contaminated with asbestos from Libby, Montana was used in many houses and business in Montana and other states. For more information on Libby and vermiculite insulation CLICK HERE.

Vermiculite is a naturally occurring mineral that can be expanded into accordion shaped pieces when heated. The insulation material is pebble-like, pour-in product, usually light-brown or gold in color. Not all vermiculite insulation is contaminated with asbestos fibers.


Zonolite Insulation from Libby
Zonolite Insulation from Libby

What To Do If You Find It In Your Home

Anthophyllite asbestos was milled for use as wall and ceiling insulation at several locations in the Bozeman, Montana area between 1925 and the late 1950s. Processing at these mills was inconsistent and distribution is not thought to be widespread. However, homes and commercial buildings constructed prior to 1960 in the Bozeman, Livingston and Helena areas may contain anthophyllite insulation. If you believe the insulation in your home or business may contain asbestos avoid disturbing the material and refer to informational resources such as the Montana DEQ Asbestos Control Program webpage to be sure any asbestos containing materials are handled safely and in accordance with applicable regulations.

Additional homeowner information on asbestos can be found at DEQ's Asbestos Control Program Homeowner Basics webpage.

What To Do If You Find It In Your Yard

Raw asbestos ore from the Karst and other Montana asbestos mines was historically stockpiled at locations in Gallatin County and can be found in soils where it was disposed of or used as fill material. If you believe you have found raw asbestos ore in soils in Bozeman or surrounding areas do not disturb or transport the soil and contact the Montana DEQ at (406) 841-5068.


Asbestos ore from the Karst Mine
Asbestos ore from the Karst Mine

Asbestos Testing and Removal

If you would like to collect a sample or have your home or business inspected for asbestos, lists of asbestos consultants, contractors, and labs can be found at:


Health Effects of Asbestos

According to the Agency for Toxic Substances and Disease Registry, people who are exposed to asbestos through breathing in the asbestos fibers may have an increased risk of developing respiratory disease such as lung cancer and mesothelioma, a rare form of lung cancer. For more information on the health effects of asbestos CLICK HERE.

Gallatin County Asbestos Remediation to Date

Asbestos ore from the Karst and other asbestos mines in Montana was historically stockpiled at locations in Gallatin County.

  • Asbestos at two sites, Montana Rail Link Asbestos and Gallatin Gateway, has been removed and both properties were delisted from the CECRA Priority List in 1996.
  • City-owned property in Bozeman at the CMC Asbestos Bozeman Facility has been cleaned up and is the home to the new Bozeman Public Library.
  • A supplemental investigation of adjacent properties near the library was conducted in 2007. Work to remove remaining contaminated soil on those properties is scheduled for the summer/fall of 2008. For more on the CMC Asbestos Bozeman Facility CLICK HERE.
  • Asbestos Awareness training sessions were conducted by DEQ in February and March of 2008 to assist in accurate identification and reporting of asbestos ore and insulation in the Bozeman area.