Until the 1970s, many types of building materials, friction products, and insulation materials contained asbestos. Asbestos fibers may be released into the environment if the material becomes damaged (loose, crumbly, or water-damaged) or if the material is repaired or removed (sanded, sawed, cut, torn, drilled, or scraped) improperly.
Exposure to asbestos poses serious health risks and environmental impacts. Today, manufacturers must label products that contain asbestos. However, asbestos-containing materials (ACMs) manufactured years ago may not be labeled. For that reason, labeled and unlabeled ACM may be present in building construction materials, automotive parts, and heat-resistant fabrics, packaging, gaskets and coatings.
Three Forms of Common ACMs
Common forms of ACMs include:
- Spray applied or troweled-on decorative, soundproofing, or fireproofing materials (including patching and joint compounds and textured paints) for beams, ceilings, walls, or crawlspaces of commercial and residential structures and schools.
- Thermal system insulation (such as asbestos blankets or paper tape) for boilers, furnace ducts, water and steam pipe elbows, fittings, and pipe runs.
- Miscellaneous materials that are not spray applied, troweled on, or classified as thermal system insulation, such as:
- Ceiling and floor tiles (such as vinyl, asphalt, and rubber resilient floor tiles)
- Siding and roofing materials (such as cement roofing and shingles)
- Gasket materials (such as door gaskets in furnaces, wood stoves, and coal stoves)
- Cement sheet, millboard, and paper used as insulation around furnaces and wood stoves
- Automotive products such as brake pads and linings, clutch facings, and gaskets (These products wear down through normal use. Asbestos fibers become trapped within the clutch space or brake housing and can be released when repair and replacement work is done. Using compressed air or vacuuming the brake residue with a regular shop or home vacuum further spreads the asbestos fibers. It is not possible to tell whether brake or clutch components contain asbestos simply by looking at them. Packaging information and Safety Data Sheets for newer vehicles and parts may indicate whether a component contains asbestos. For older vehicles or vehicles that have had brakes replaced, there may not be any way to confirm whether existing components contain asbestos.)
Regulatory Categories of ACMs
ACM is either friable, which means the material can be crushed or crumbled by hand pressure, or nonfriable, which means the material cannot be crushed or crumbled by hand pressure. If severely damaged, even materials that are otherwise nonfriable can release significant amounts of asbestos fibers.
The federal asbestos regulations (40 CFR 61, Subpart M) identify ACM in three main categories:
- Friable ACM.
- Category I nonfriable ACM (includes packing, gaskets, resilient floor coverings or asphalt roofing products).
- Category II nonfriable ACM (includes any nonfriable ACM not in Category I). Examples are cement siding, transite board shingles and other such materials that are subjected to intense weather conditions such as thunderstorms, high winds or prolonged exposure to high heat and humidity and may become "weathered" to a point where they become friable.
Regulated Asbestos-Containing Materials (RACMs)
- Friable ACMs,
- Category I nonfriable ACM that has become friable,
- Category I nonfriable ACM that will be or has been subjected to sanding, grinding, cutting or abrading, or
- Category II nonfriable ACM that has a high probability of becoming or has become crumbled, pulverized, or reduced to powder by the forces expected to act on the material in the course of demolition or renovation operations.