Asbestos Insulation: Identification and What to Do

Asbestos was once added to home insulation because it was strong and fireproof. This type of insulation was then used for insulating walls, floors, pipes, ductwork, and beams. In the early 1970s, researchers discovered that asbestos-containing materials adversely affected health, though the material may still be in places around some older homes.

Asbestos insulation comes in many forms and can look loose, lumpy, and fluffy like wool or hardened like corrugated cardboard or pebbly, and has a gray, gray-brown, or silvery gold color. Learn how to identify various types of asbestos insulation and what to do if you find it in your home.

What Is Asbestos Insulation?

Asbestos is a strong, natural mineral fiber that is resistant to heat and won't corrode. Companies, such as Armstrong, Celutex, Owen Corning, and dozens of other manufacturers producing and using it were impacted when the Environmental Protection Agency began to phase out asbestos insulation in 1975, although vermiculite asbestos insulation continued to be placed in some homes.

The EPA prohibited spray-on applications of the product in 1990. In 2019, the EPA reintroduced new and final asbestos restrictions.

Why Is Asbestos Insulation Dangerous?

Asbestos insulation is one of the most hazardous materials found in homes. Disturbing and breathing asbestos fibers can cause asbestosis, lung cancer, and mesothelioma.

When moved, removed, disturbed, or damaged, asbestos insulation can become a danger in the home during renovations and repairs. Moving asbestos insulation will cause toxic asbestos fibers to become airborne and potentially inhaled by occupants.

What Does Asbestos Insulation Look Like?

Spray-on Insulation

Spray-on insulation can be identified as a thick layer of gray material on the ceiling. This insulation is made up almost entirely of asbestos. When it is disturbed or damaged, asbestos fibers become airborne.

Loose-Fill Insulation

The type of insulation most commonly made with asbestos is loose-fill, also called blown-in insulation. Loose-fill insulation comes in a variety of materials and is easy to identify by its loose, lumpy form and fluffy or granular texture. Loose-fill insulation does not have a paper backing. It was placed on the attic's flooring or blown into a wall's empty spaces.

Block Insulation

This type of wall insulation looks like boards and they are made entirely of asbestos. When these asbestos insulation boards or blocks are sawn apart or manipulated in any other way, asbestos is released into the air.

Blanket/Wrapped Pipe Insulation

Pipes in basements, furnace rooms, and utility rooms may be wrapped with asbestos insulation. There are two types: asbestos air-cell insulation and asbestos wool insulation.

• Asbestos air-cell insulation: This insulation looks like corrugated cardboard or paper and is an off-white or gray color. The insulation will be fully wrapped around the pipes, often with an outer casing to hold the insulation on the pipes.
• Asbestos wool insulation: This insulation is fibrous or fluffy and wool-like. Asbestos wool insulation was wrapped around pipes and releases asbestos fibers as this woven type of fabric ages.
  

Vermiculite Insulation

Vermiculite loose-fill insulation has a pebble-like appearance and typically is grayish-brown or silvery-gold in color. It is made from a natural mineral mined from the earth which expands when heated, creating the lightweight and somewhat stony-looking particles that make up the insulation. Houses built before 1990 may contain vermiculite insulation that contains asbestos.

Most vermiculite insulation containing asbestos in the U.S. was sourced from a mine near Libby, Montana. The raw vermiculite material taken from the mine was contaminated with asbestos. Insulation made from this material represents over 70% of the vermiculite insulation found in U.S. homes.

Because the Libby mine closed in 1990, houses built or remodeled before that date might have asbestos-containing insulation. If the house was built after 1990, the chance that your house has asbestos-contaminated insulation is reduced but not eliminated.

Insulation That Likely Does Not Contain Asbestos

Common forms of household insulation typically do not contain asbestos and are considered to be safe: batt or blanket fiberglass insulation, cellulose insulation, loose-fill insulation, and rock wool insulation.

Batt or Blanket Insulation

Batt or blanket insulation comes in long strips about 16 inches wide. A popular brand of fiberglass batt insulation is pink, while other brands are generally white. Batt or blanket insulation is sometimes shredded by hand by the installer to fit wads of the insulation around obstructions. If your attic or wall insulation is in batt or blanket form, you generally don't have to be concerned about asbestos.

Cellulose Insulation

Cellulose is a loose-fill insulation that is gray, soft, and without a shine. It contains a high percentage of recycled paper and does not contain minerals. Cellulose looks like shredded gray paper, which looks different than asbestos insulation. Cellulose insulation is a perfectly safe type of insulation that is commonly blown into attics. It also comes in batt and blanket forms.

Loose-Fill Fiberglass

Fiberglass fill is a loose-fill insulation that is white and fluffy and has a little shine. The insulation may produce a slight shine when exposed to bright light because fiberglass is a glass product. It is very soft, almost like cotton candy, and composed of very fine fibers.

Rock Wool Insulation

Rock wool is a loose-fill insulation that has a fibrous, soft, cottony texture. It is usually gray, white, off-white, or brownish-white. It is made by melting basaltic rock and dolomite with added binders. The raw material is heated to 2,750° Fahrenheit until it melts, then the molten material is spun into fibers with air pressure. Rock wool is installed as loose insulation or as woven insulation batts.

What to Do With Asbestos Insulation Around the Home

If your loose-fill insulation fits the visual cues for vermiculite, the first thing to do is to avoid disturbing it. Asbestos fibers are most dangerous when they are airborne and can be breathed in. Leaving insulation undisturbed greatly reduces the risk of exposure.

You can test the insulation for asbestos using an asbestos testing kit or by having a sample tested at an approved testing laboratory. If you discover that you do have insulation containing asbestos, you can leave it in place or have it removed by a local asbestos abatement company.

For more information on dealing with vermiculite insulation, the U.S. Environmental Protection Agency (EPA) provides a wealth of information about identifying asbestos insulation, safety procedures, and how to remove it.