Top; is an example of asbestos siding. Middle; shows workers blowing in thermal insulation. Above; a typical popcorn acoustical ceiling.

Asbestos abatement workers looking like NASA technicians suiting up, and working on removing asbestos on a commercial site.

Micrograph of tremolite asbestos fibers.

When the fire retardation property of asbestos was discovered, it was heralded as a wonder product. And it has proved to live up to its expectations. Applications have included everything from welding gloves to building insulation to brake pads.

But, like so many things that have wide-ranging, even life-saving applications, asbestos has a dark side. When the small microscopic fibers that make up manufactured asbestos products are released into the air, they can be inhaled by building occupants or workers. Over time, a scar will develop around the fiber or fibers in the lung or stomach and diseases such as asbestosis, mesothelioma, or lung cancer can develop. The latency period averages about 20 to 30 years. Since asbestos started to be used widely in the 1920s, it wasn’t until the 1960s and 1970s that people who had been exposed to the fibers began to be diagnosed with these diseases. Gym teachers in schools (from breaking ceiling tile), factory workers, and insulation and fireproofing contractors were just a few of the people who were dying. The grandfather of one of the authors of this article worked in an asbestos factory when he was in his late teens and twenties. When he was in his sixties, he was diagnosed with asbestosis, and subsequently died of the disease. Beginning in the 1970s and into the 1980s asbestos was banned in most products.

The problem wasn’t confined to commercial or industrial application. Asbestos was also used in homes. The following is just some of the materials in the home that can contain asbestos: Popcorn Acoustical Ceiling, Acoustical Ceiling Tile, Duct Tape, Pipe Insulation, Thermal Insulation (blow-in, bat, or spray-on), Electric Wire Insulation, Vinyl Floor Tile, Linoleum Sheet Flooring, Floor Tile Mastic, Wallboard Mud, Plaster Skim Coat, Wallboard (rare), Siding, Municipal Water or Sewer Pipes, Roll-On Roofing, Window Glazing, Woodstove, Furnace, or Oven Door Gaskets, Fireproofing, Grout

As indicated in the list, there are many materials that can contain asbestos in a home built before the ban on their manufacture. Some materials in homes built after the ban can contain asbestos because inventories of the materials were still used into the 1980s.

But what is the real risk? Asbestos is typically divided into the categories of friable and non-friable. Friable materials can be broken down by hand, such as acoustical popcorn ceiling, duct tape, insulation, etc. Non-friable material cannot be broken down by hand, such as siding. However, non-friable material can become friable if damaged. Risk is determined by two exposure factors: 1) length of exposure; and 2) magnitude of exposure. For instance, if a person is exposed to a very small amount of asbestos for a very short period of time, potential for contracting a disease is low. But if a person is exposed to a large amount of material for a short time, or a small amount of material continuously for a long time, potential for disease increases.

One of the biggest problems we see in home exposure is where the heat register blows air across asbestos-containing material (such as popcorn ceiling) for a long period of time, effectively eroding the asbestos out of the material. Usually, though, as long as the material is not disturbed, there is little risk of exposure. High, short-term exposures happen when the material is broken apart, scraped off, or ripped during remodeling or home improvement projects.

There are three methods to reduce the potential exposure to asbestos in a home:

1) Remove the material
2) Encapsulate the material
3) Maintain the material.

Removal is recommended because it effectively gets rid of the offending material. Encapsulation involves covering the material. For instance, spraying a layer of paint over a popcorn ceiling or brushing epoxy over duct tape will reduce the possibility of fiber release. Installing an attic floor over asbestos insulation will reduce exposure when working in the attic. Maintenance of asbestos-containing material means that an effort is made to keep the material from becoming friable or to keep fibers from becoming exposed. For instance, the asbestos in sheet flooring is found in the paper backing that isn’t normally exposed. However, if the flooring is partially ripped up or cut open, the paper backing becomes exposed and fiber release is possible. Maintenance of the flooring either ensures that no damage occurs to the floor or if damage occurs it is quickly repaired.

New rules in the State of Oregon require that any material that is going to be disturbed during remodeling or demolition must be investigated for the presence of asbestos (Washington state rules are similar). However, there is an exemption for “owner occupants of a single private residence or owners of a single private residence that is not used as a rental property, commercial business, or intended for demolition.” A homeowner, then, can remove or encapsulate material without complying with the rules that commercial operators must comply with, but it can be difficult to dispose of the material because some disposal facilities might require testing for asbestos. When removing suspected asbestos-containing material, it is important to eliminate fiber release as much as possible. For instance, wetting or spraying epoxy over friable material prior to removal can bind up most fibers. Non-friable material such as siding can be removed carefully to reduce breakage and fiber release. Asbestos abatement contractors can remove material with a minimal amount of fiber release.

In summary, asbestos-containing materials can be a problem in a home, but the risk of exposure can be reduced significantly by removal, encapsulation, or maintenance.

William CullochDasson is a registered professional geologist with over 12 years experience in the environmental field and Ed Woodward, with over 13 years experience runs the asbestos division of 3 Kings Environmental, Inc. They can be reached at 360-666-5464, or by email: BillC@3kingsinc.com.