Asbestos is a naturally occurring substance, which was widely used because of its ability to withstand high heat loads without burning or breaking down. Unfortunately, it was discovered that over time it breaks down into small fibers that, when ingested, become lodged in the lungs where they build up and destroy the tissue and can cause serious health problems. iMesothelioma, a cancer of the chest and abdominal membranes, is caused by the inhalation of asbestos. an Asbestosis is a chronic disease of the lung that makes breathing progressively more difficult. These diseases can lead to death but, because asbestos has a latency period of twenty to forty years, it takes a while for manifestation of the symptoms.

In 1971, asbestos was listed as an EPA hazardous air pollutant but, because its use in the past was widespread, it is still possible to find it in a variety of residential and commercial applications. Asbestos should only be considered a problem if it is breaking down or falling apart, allowing its fibers to become airborne. Removal or encapsulation (sealing the asbestos, normally beneath a wrapping of epoxy) should only be conducted by a licensed contractor trained to handle the remediation of it. If asbestos is found and is in good condition, care should be taken not to disturb it or damage it. Below is a list of common places where asbestos can be found. If in doubt, a sample of the suspected material can be collected by a professional testing company and tested for its content.

Hot Water and Steam Pipes

Between 1920 and 1972, asbestos was pre-formed in half rounds then wet-gauzed in place around pipes. Pipes were also wrapped in asbestos paper tape. If a whitish material is around the pipes (usually in the basement), it may be asbestos. Test, monitor and take further steps as necessary.

Ducts and Furnaces

In the 1940's and 1950's, ducts and furnaces were insulated with asbestos-impregnated papers. Chalk colored insulation was applied as flat sheets as thin as 1/16" or as a corrugated version. If the asbestos breaks down it can be released into the ventilation system. Asbestos cement was heavily used for heating ducts built into concrete slab floors in houses built in the 1950's through the late 1970's. Inspection of these is highly recommended.

Boiler wraps

Usually made of chalky blocks approximately 2" thick, they were fastened to boilers by wires or metal straps and then coated with plaster-saturated canvas. High humidity or water can cause it to breakdown and disintegrate quickly. They were in use up to 1975.

Insulation

Asbestos can be found in wall, ceiling, and attic insulation constructed between 1930 and 1950. It is usually found inside of the house, sandwiched between the framing and the plaster walls. If this is found, professionals should be called for any remodeling or renovations.

Roofing and Siding

From the 1940's through the 1960's, asbestos cement was commonly used for roofing shingles. The shingles are usually gray and can bear brownish-white streaks where water drains more slowly. They will make a dinging sound when hit with an object. Between the 1930's and the 1970's, asbestos-cement shingle siding was also used. These shingles can be any color and they have a propensity to crack and chip along their edges. Although general use was discontinued, some are still being used. If the shingles are breaking apart, care should be taken that the fibers do not enter the house through open windows and doors.

Joint Compound and Textured Paint

Until 1977, joint compound used to tape joints in wallboard and fill holes in plaster contained up to fifteen percent asbestos. Textured paints before 1978 may also contain asbestos. Do not disturb these substances if they are in good condition. In 1977, the Consumer Product Safety Commission banned patching products containing asbestos because of their health risks.

Fireproof Board

Still being manufactured, these boards are 1/4 to 3/4" sheets, gray in color, almost resembling plasterboard. They can be found around wood burning stoves, oil, coal or wood furnaces to protect the floors and walls around them. The board may be brittle so care should be taken around it.

Asbestos Ceiling Tiles

Usually a brownish material, asbestos can be found in acoustic tiles that are often seen in recreation rooms. They are still being made today, so ask the manufacturer if you suspect asbestos. As long as they are in good condition there should be no worries.

For further information regarding asbestos, contact the Environmental Protection Agency's Asbestos hotline at 202.554.1404.