Asbestos

Asbestos was used in thousands of building products until the 1980s, and much of it is still in place today. When it’s disturbed, microscopic fibers float in the air, get breathed deep into the lungs, and can cause asbestosis, lung cancer and mesothelioma decades later. There is no known safe level of exposure.

Asbestos deep dive: This page is the starting point. Go deeper with Asbestos Laws Explained (OSHA, EPA, schools and the asbestos ban), Asbestos Licenses & Training, Asbestos Rules by State, and, for homeowners, Asbestos for Homeowners.

Photo: common asbestos-containing materials: pipe lagging, 9-inch floor tile, popcorn ceiling, transite siding, vermiculite

What asbestos is

Asbestos is a group of natural minerals that form long, thin, strong fibers. It doesn’t burn, resists heat and chemicals, and was cheap, so it was added to insulation, cement, flooring, roofing, brakes and many other products. The most common type in U.S. buildings is chrysotile (white asbestos). Amosite (brown) and crocidolite (blue) were also used, especially in insulation.

Asbestos-containing materials (ACM) are divided into two groups:

What it does to your body

DiseaseWhat it isTypical time after exposure
AsbestosisScarring of the lungs that makes breathing harder and harder. No cure.10 to 20+ years
Lung cancerCancer of the lungs. Smoking and asbestos together multiply the risk many times over.15 to 35 years
MesotheliomaA rare, almost always fatal cancer of the lining of the lungs or abdomen. Caused almost only by asbestos.20 to 50 years
Pleural plaques and thickeningScarring of the lining around the lungs. A marker of exposure that can reduce lung function.20+ years
Other cancersCancers of the larynx and ovary are also linked to asbestos.Decades

Because these diseases show up so long after exposure, people don’t feel anything at the time. That’s why asbestos rules focus on preventing exposure completely, not on how you feel. If you’ve worked around asbestos, tell your doctor, and if you smoke, quitting greatly lowers your lung cancer risk.

Where you might find it

Any building built before 1981 may contain asbestos, and some products were made or installed later. Common places include:

WhereExamples
Mechanical systemsPipe, boiler, tank and duct insulation (“thermal system insulation”); gaskets; packing; furnace and boiler cement
Ceilings and wallsSprayed-on fireproofing, acoustic “popcorn” ceilings, textured plaster, drywall joint compound, ceiling tiles
Floors9-inch by 9-inch vinyl tiles, other vinyl tile and sheet flooring and its backing, black mastic (adhesive)
Exterior and roofingCement siding and shingles (“transite”), roofing felts, flashing cement, roof coatings, window glazing putty and caulk
Other building partsCement pipe (water and sewer), fire doors, electrical panels and wire insulation, lab countertops, chalkboards
HomesVermiculite attic insulation (much of it from a mine contaminated with asbestos), old furnaces and their ducts, stove and fireplace parts, old appliances
Industrial and vehiclesBrakes and clutches, refractory linings in kilns and furnaces, turbine and ship insulation

You can’t tell if something contains asbestos by looking at it. The only way to know is to have a sample tested by an accredited laboratory, usually by polarized light microscopy (PLM).

Presumed asbestos-containing material (PACM)

Under OSHA, thermal system insulation and sprayed or troweled surfacing material in buildings built in 1980 or earlier must be treated as asbestos-containing unless it’s tested and shown not to be. Asphalt and vinyl flooring installed in 1980 or earlier is also presumed to contain asbestos.

Building and facility owners must find out whether ACM and PACM are present before work starts, and tell employers and workers where it is. Employers must tell their workers before they work in those areas.

The OSHA rule for workers

The four classes of construction asbestos work

ClassWhat it coversMinimum training
Class IRemoving thermal system insulation and sprayed or troweled surfacing material that is ACM or PACM. The most hazardous.Equivalent to the EPA accredited worker course (32 hours) or supervisor course (40 hours)
Class IIRemoving other ACM that isn’t TSI or surfacing, such as floor tile, siding, roofing and masticAt least 8 hours of hands-on training for the specific work
Class IIIRepair and maintenance where ACM or PACM is likely to be disturbedEquivalent to the EPA 16-hour operations and maintenance course
Class IVMaintenance and custodial work where workers contact but don’t disturb ACM, such as cleaning up debrisAt least 2 hours of awareness training

Workers in Class I, II and III work, and anyone exposed above the PEL for 30 or more days a year, must get medical surveillance paid for by the employer. Many states also require a state license or certification for asbestos workers, supervisors and contractors. See Asbestos Licenses & Training.

Other laws you’ll hear about

All of these are explained in Asbestos Laws Explained and Asbestos Rules by State.

If you find suspect material

  1. Stop work if you uncover material that might be asbestos and wasn’t identified in the survey.
  2. Don’t disturb it further. Don’t break, sand, drill, scrape, sweep or vacuum it with a regular vacuum.
  3. Keep people away and tell your supervisor or the building owner.
  4. A trained, accredited inspector must sample it and have it tested.
  5. If it’s asbestos, only trained and (where required) licensed workers with proper respirators, containment and decontamination may remove, repair or enclose it.

Don’t take it home. Asbestos fibers carried home on clothing, hair and tools have caused mesothelioma in spouses and children. Use the decontamination area, change out of work clothes, and never shake out or launder asbestos-contaminated clothing at home.

How abatement is done (overview)

Video: inside an asbestos abatement containment: negative air, decon unit and wet removal

Standards & references

Related: Asbestos Laws Explained · Asbestos Licenses & Training · Asbestos Rules by State · Asbestos for Homeowners · Abatement Workers · Demolition

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