Asbestos Fact Sheet

Asbestos was used in a wide varitey of building materials and building components during the twentieth century. The widest use occurred from 1940 – 1975.

Among the building materials found to contain asbestos are:

  • accoustical texture
  • Fire-proofing
  • plaster
  • joint compound
  • wall texture
  • spackle
  • attic and wall insulation
  • resilient flooring
  • mastic
  • recessed lighting fixtures
  • wiring
  • elevator brakes
  • fire doors
  • piping insulation
  • piping joints
  • gaskets
  • valve packing and insulation
  • exhaust pipe
  • exhaust hoods
  • lab benches
  • blackboards
  • duct insulation
  • duct tape
  • boiler blocking
  • vibration damping cloth
  • building panels
  • siding
  • shingles
  • roofing felt
  • roofing tar
  • textured paint
  • flashing
  • water-proofing putty
  • window caulking
  • door insulation
  • stucco
  • mortar
  • concrete
  • swimming pool plaster
  • asbestos cement pipe, shingles, panels, siding (transite™)

Asbestos is hazardous when inhaled. When asbestos-containing materials deteriorate or are damaged, asbestos fibers are released into the air. Fibers that are inhaled can lodge and remain in the lungs, or migrate to other locations in the body. Asbestos fibers have been shown to cause asbestosis, lung cancer and mesothelioma. Especially at risk are 1) occupationally exposed workers (mainly in the construction industry), 2) children, who will retain any inhaled fibers for decades, and 3) occupationally exposed smokers, who experience a greatly enhanced risk of lung cancer.

The most likely building materials to release fibers are those that are most likely to be damaged (friable materials). Typical friable materials are fireproofing on beams, acoustical texture and ceiling tiles. Non-friable materials are not likely to release fibers unless heavily damaged (made friable). Typical non-friable materials include vinyl floor tile, asphaltic roofing, mastics and asbestos-cement (transite) materials.

Current federal regulations 1) ban most mechanical system insulation and spray applied products, but do not restrict the use of most of the above bulleted list in new buildings, 2) specify work practices for the disturbance of asbestos-containing material, and 3) require the identification of asbestos in schools (AHERA) and in commercial and public buildings that are to be remodeled or demolished by either assuming or presuming it’s presence or by sampling (OSHA, NESHAP). Exposure standards exist for the workplace (OSHA) and to clear abatements in schools (AHERA).

ASTM International has also published three standards for asbestos control, and may be accessed at


ACM: Asbestos containing material wit greater than 1% asbestos. The current regulatory threshold in most cases.

AHERA: Asbestos Hazard Emergency Response Act (1986); legislation requiring the cataloging of asbestos containing building materials in schools. 40 CFR 763, Subpart E.

Asbestiform: tending to separate into fibers having length:width ratios from 10:1 to over 100:1.

Asbestos: any of a group of commercially mined minerals that tend to break into fibers. The regulated asbestos minerals are the serpentine mineral chrysotile and the asbestiform varieties of the amphibole minerals grunerite (amosite), riebeckite (crocidilite), tremolite, actinolite and anthophylitte. Amphibole minerals occure in both the regulated, asbestiform varieties and the non-regulated, non-asbestiform varieties. Asbestos fibers are resistant to high temperatures, have high tensile strength, and in some cases can be woven into cloth.

Asbestosis: a chronic fibrosis of the lungs caused by large exposures to asbestos, usually affecting miners, ship-builders and mill-workers.

EPA: Environmental Protection Agency; environmental issues government agency.

f/cc: fibers per cubic centimeter; reporting units for PCM analyses.

friable: able to be crumbled to powder by hand pressure when dry.

Mesothelioma: cancer of the lining of the lung or intestines.

NESHAP: National Emission Standard for Hazardous Air Pollutants.
40 CFR 61, Subpart M.

Non-asbestiform: tending to break into cleavage fragments having length:width ratios from 2:1 to 20:1.

OSHA: Occupational Safety & Health Administration; requires that workers be protected from asbestos exposure.
29 CFR 1926.1101, 29 CFR 1910.1001.

PCM: phase-contrast microscopy, an optical microscopy method used to perform fiber counts on air sample filters. Its disadvantages for asbestos analysis are that 1) it cannot resolve all asbestos fibers, and 2) it cannot distinguish asbestos fibers from other fibers.

PEL: permissible exposure limit; OSHA mandated maximum exposure level for workers without respiratory protection (8 hour time weighted average 0.1 f/cc and 30 minute exposure 1.0 f/cc).

PLM: polarized light microscopy method used to analyze bulk samples for asbestos content; required by both OSHA and EPA as the basic analytical method to determine applicability under the asbestos regulations.

structures/mm2: asbestos structures, as defined by AHERA (fiber, bundle, matrix or cluster), per square millimeter of filter; reporting units for AHERA TEM analyses.

TEM: transmission electron microscopy, highly technical equipment used to perform asbestos analysis on air samples. It can resolve and distinguish all asbestos fibers from other fibers. Required for “final clearance” before re-occupancy in schools under AHERA.

The primary federal asbestos regulations are:

  • OSHA Asbestos in the construction industry (29 CFR 1926.1101)
  • OSHA Asbestos in general industry (29 CFR 1910.1001)
  • OSHA Respiratory protection (29 CFR 1910.134)
  • EPA AHERA: Asbestos in schools (40 CFR 763, subpart E)
  • EPA NESHAP: Control of emissions, waste management & disposal(40 CFR 61 subpart M).
  • EPA Model Accreditation Plan: certified persons and specifications (40 CFR 763, appendix C of subpart E)
  • EPA Worker Protection: protects asbestos workers excluded from federal OSHA (40 CFR 763, subpart G)