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 it builds up and destroys the tissue and can cause serious health problems including Mesothelioma which is a cancer of the chest and abdominal membranes caused by the inhalation of asbestos and Asbestosis, a chronic disease of the lung which makes breathing progressively more difficult. These diseases can lead to death but because it 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 places in both 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 a heavily used material 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.
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.
Asbestos can be found in wall, ceiling, and attic insulation constructed between 1930 through 1950. 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. They can be any color and they have a propensity to crack and chip along their edges. Although general use was discontinued, it is sometimes 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 if it is in good condition. In 1977, the Consumer Product Safety Commission banned patching products containing asbestos because of their health risks.
Still being manufactured, these boards are 1 / 4 to 3 / 4" sheets, gray in color, almost resembling plasterboard. It can be found around wood burning stoves, oil, coal or wood furnaces to protect the floors and walls around them. It may be brittle so care should be taken around it.
Asbestos Ceiling Tiles
Usually a brownish material, it can be found in acoustic tiles that are often seen in recreation rooms. Even today they are being made so ask the manufacturer if there are any doubts. But as long as they are in good condition there should be no worries.
If further information regarding asbestos is needed, it may be obtained from the Environmental Protection Agencies Asbestos hotline at 202.554.1404