Categories Of Asbestos Containing Materials
The Environmental Protection Agency (EPA) published the National Emission Standards for Hazardous Air Pollutants (NESHAP) for asbestos in 1973 as required by Section 112 of the Clean Air Act. In the original asbestos NESHAP, the EPA divided asbestos-containing material (ACM) into two categories: friable and non-friable. A friable ACM is one which is likely to release asbestos fibers into the air when it is disturbed, and a non-friable ACM is one that is not likely to release significant fibers into the air (1).
More specifically, according to the asbestos NESHAP, a friable ACM is a material containing more than 1% asbestos that can be crumbled, pulverized or reduced to powder by hand pressure when it is dry. A non-friable ACM is a material containing more than 1% asbestos that cannot be crumbled, pulverized or reduced to powder by hand pressure when it is dry (2).
The EPA defines two categories of non-friable ACM: Category I and Category II.
A category I non-friable ACM is any asbestos-containing packet, gasket, resilient floor covering, mastic or asphalt roofing product that contains more than 1% asbestos. Category I ACM is pliable (not brittle), breaks by tearing rather than fracturing, and does not easily release asbestos fibers upon breaking. Category I materials must be removed from a structure before demolition if they have become friable through damage or are likely to during demolition.
A category II non-friable ACM is, generally, any kind of non-friable ACM that is not covered under Category I. This includes rigid exterior siding and boards known by the trade name "transite". Category II ACM is not pliable, breaks by fracturing rather than tearing, and does release some asbestos fiber release upon breaking. Category II materials usually must be removed from a structure before demolition, and they must be wetted to prevent dust and placed in covered containers (3).
Since the original NESHAP distinction was made between friable and non-friable, the EPA has determined that non-friable ACMs can release asbestos fibers when they are badly damaged. Thus, even category I or II non-friable ACMs may be come friable if exposed to enough weather damage, burning, cutting, sanding, etc. The EPA has therefore defined a "regulated asbestos-containing material" (RACM) as any friable ACM, any category I non-friable ACM that has become friable, and any category II ACM that is likely to be crumbled, powdered or pulverized by actions taken during renovation or demolition (1).
Generally, any material that qualifies as RACM is subject to NESHAP rules. Friable, category I and category II non-friable materials have different requirements for handling during renovation, removal, burning, demolition, transport and disposal (4). These rules may vary on a state and local level.
'Categories Of Asbestos Containing Materials' Sources:
- U.S. Environmental Protection Agency. "Asbestos/NESHAP Regulated Asbestos Containing Materials Guidance." Region 4, Asbestos (2007). http://www.epa.gov/region4/air/asbestos/asbmatl.htm 14 July 2007.
- U.S. Environmental Protection Agency. "National Emission Standards for Hazardous Air Pollutants." 40 CFR, Section 61.141, Subpart M (1984).
- Wisconsin Department of Natural Resources. "Types of Asbestos." Fact Sheet on Asbestos Disposal (April 2006). http://www.dnr.state.wi.us/org/aw/air/reg/asbestos/asbes5.htm 14 July 2007.
- U.S. Environmental Protection Agency. "Demolition Practices Under the Asbestos NESHAP." Region 4, Asbestos (2007). http://www.epa.gov/region4/air/asbestos/demolish.htm 14 July 2007.