Naturally Occurring Asbestos

This Technical Working Group has the responsibility of communicating news and regulatory information regarding management, mapping, sample collection, laboratory analysis techniques, construction mitigation, education, and regulatory requirements related to the natural occurrences of asbestos and asbestiform minerals within the United States. The technical working group activities include:

  • Quarterly dinner meetings with an invited speaker
  • Improving public and industry awareness of the variety of issues related to NOA
  • Providing input to local, state, or federal regulators
  • Publishing papers and organizing AEG's Naturally Occurring Asbestos Symposia and Field Trips

Chairs: Sarah Kalika & Mark Bailey

Contact one of the co-chairs shown above if you are interested in joining us at the next meeting or for more information visit our group's independent website.


We’re now an IAEG Commission!  The co-chairs of AEG’s Technical Working Group, along with colleagues in Italy and South Korea, have successfully petitioned IAEG to create Commission 39: Naturally Occurring Asbestos.  IAEG Commission 39 and AEG’s TWG will work as a single group to advance the development of analytical laboratory practices and awareness of NOA and Elongate Mineral Particles on a global scale. Please let us know if you’re interested in joining our group.  

Asbestiform overgrowth within actinolite sample (magnified 843x with scanning electron microscope)  Photo by Mark Bailey, Asbestos TEM Labs

Chrysotile veins in serpentinite under crossed-polars of polarized light microscope  Photo by Mark Bailey, Asbestos TEM Labs
Selected links to guidance documents

EPA: Naturally Occurring Asbestos: Approaches for Reducing Exposure

Alaska Department of Environmental Conservation: Naturally Occurring Asbestos in Alaska
Alaska DOT: Naturally Occurring Asbestos Program


California Department of Toxic Substances Control: Interim Guidance Naturally Occurring Asbestos (NOA) at School Sites, Revised 9/24/04 (PDF)
California Geological Survey:

California Air Resources Board: Method 435: Determination of Asbestos Content of Serpentine Aggregate (PDF)
California Office of Environmental Health Hazard Assessment (OEHHA): Air Toxicology and Epidemiology
California Department of Industrial Relations: Cal-OSHA CCR Title 8, Subchapter 4, Article 4, Section 1529
California Department of Transportation:

Fairfax County:

Grading of NOA at Construction Site  Photo by Caren Wilhoit

Geologist in OSHA Class II - level personal protective equipment  Photo by Caren Wilhoit

Notable NOA Investigations, Cleanups, Mitigation Projects

Calaveras Dam Replacement, Fremont, California

SF PUC: Calaveras Dam Replacement Monitoring Results

Coalinga & Atlas Asbestos Mines, California
EPA: Coalinga Asbestos Mine

El Dorado Hills, California
ATSDR: Final Health Consultation on Asbestos Exposure in El Dorado HIlls, CA
County of El Dorado, California: Asbestos in El Dorado County

Libby, Montana
EPA: Libby Asbestos
Environmental Response Television (ERTV): Libby, Montana: An Asbestos Legacy (Video)

Sumas Mountain / Swift Creek, Washington
Washington State Department of Health: Advisory for Swift Creek Naturally Occurring Asbestos (PDF)
EPA: Sumas Mountain Asbestos


The Immediate Past President is the Coordinator of Technical Working Groups and shall provide coordination among the Groups; liaison between the Groups and the Board; and distributing Association information to various Technical Working Group Chairs.

Contact the Coordinator of Working Groups Chair or AEG headquarters to get involved.