Since the asbestos content of concrete is rarely known, mechanical abrasion (such as sawing, grinding, or sanding) and use of concrete-crushing machines is a matter of great concern. Under no circumstances should asbestos-containing concrete, or concrete to which asbestos-containing resilient flooring is attached, be subjected to such treatment.
Asbestos fibers pose a health risk when released to the air and inhaled. State, federal, and international health agencies have classified asbestos as a known cancer causing substance. Asbestos is known to cause lung cancer, mesothelioma (a rare cancer of the lung linings), and asbestosis (a non-cancer respiratory disease).
Test Methods and Precautions
Asbestos was added to a variety of building materials and is found in concrete and concrete-like products. In addition to asbestos in the concrete itself, asbestos can be present in materials used to coat the asbestos such as paints and asphalt type coatings. Some caulks, used to seal seams or joints, contain asbestos. There can also be asbestos concrete pipes or transite siding (a fireproof composite material made of asbestos and cement), and cement ducts embedded in the concrete. Cement-like products used to patch or fill concrete and brick may contain asbestos. Literally hundreds of cement-based products used for insulation, masonry, stucco, finishing, roads, and other applications contain asbestos. In other words, even if the concrete does not contain asbestos that does not mean that there are not other asbestos containing products that may need to be addressed.
An important fact to keep in mind is that the procedures used to take samples of concrete and the method used to analyze those samples for asbestos can vary. Taking samples properly is not as simple as just obtaining a piece of the concrete and sending it to a lab with instructions to test it for asbestos.
For example, in some floors, there are different layers of concrete which contain different materials. There may be asbestos in one layer of the floor but no asbestos in other layers. If samples are taken for analysis, it is important that when the samples are taken that all of the different layers or types of concrete are analyzed individually.
The test methods most commonly used will not detect all asbestos. Although the U.S.EPA has started the process of approving better test methods, that process is not complete. What that means is that a test using polarized light microscopy may not detect all of the asbestos that is present. The fact that a sample is tested using a method approved by EPA does not mean that you can be certain that the test found all the asbestos in the sample.
Asbestos in Applied Flooring Materials
Hubbellite is the brand name for a poured seamless floor that entered the market in the 1940s and is an example of applied flooring may contain asbestos. Hubbellite applied to concrete floors at Wisconsin’s Badger Army Ammunition Plant contains approximately 10 percent chrysotile or “white asbestos”. Hubbellite is composed of a mixture of cement, limestone, copper and magnesium compounds, and proprietary additives. According to the manufacturer, Hubbellite flooring is fire resistant, chemical resistant (including solvents), non-sparking, and static-disseminating.
Asbestos in “Soft” Concrete
In 1998, the EPA issued a memo alerting industry and labor organizations of the potential for asbestos in “soft” concrete in the roofs of buildings. An inspection of a roof repair project on a government building revealed that the concrete material used for forming the roof surface in 1934 contained a high concentration of asbestos.
The asbestos/concrete mixture is called “soft concrete.” Apparently, when the government building was built, asbestos was mixed with concrete to make a lighter and easier to use mixture than regular concrete. It was then used for creating the slopes on the roof. The soft concrete layer ran between two and 10 inches in thickness on the roof of the inspected building. Analysis of the concrete revealed it had an asbestos content of between two and 10% by weight.
At the time the memo was issued, OSHA had no data on how many buildings might have soft concrete on their roofs. It is possible that such a mixture was used on other roofs and, therefore, its presence could pose “significant health hazards during demolition or repair work”. Furthermore, employees occupying a building might be exposed to the asbestos from the roof’s materials if there are openings in the building, particularly during re-roofing work.
Military Formulation Insulation Cement
Military Formulation of Super Powerhouse insulation cement (produced from 1957 to 1971) contained 5% chrysotile asbestos and was developed to conform to government specification. This product was manufactured and sold exclusively for U.S. government military installations. (The commercial formulation without asbestos continued in production.) Both products were dry, mixtures containing spun mineral-wool, hydraulic setting binders, clays and other ingredients. Its use in or on concrete is not known.
SOURCES:
U.S. Environmental Protection Agency Region 4, Demolition Practices Under the Asbestos NESHAP, undated.
California Department of Toxic Substances Control, “Public Involvement Fact Sheet, DTSC Recommends Resurfacing of Serpentine Gravel Roads based on Garden Valley Study,” April 2005.
Minnesota Pollution Control Agency, Water Quality/Wastewater Permits #3.01, September 2004.
U.S. Environmental Protection Agency Region 5, Air Enforcement Program, electronic communication to Laura Olah, Citizens for Safe Water Around Badger, May 27, 2005.
Wisconsin Department of Natural Resources, Air Management Division, electronic communication to Laura Olah, Citizens for Safe Water Around Badger, May 4, 2005.
U.S. Environmental Protection Agency, Directorate of Technical Support, Hazard Information Bulletin, Potential Asbestos Contamination in Soft Concrete Information, October 8, 1998.
U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pollution Prevention and Toxics, Asbestos, Publication of Identifying Information, Federal Register, Volume: 55, Issue: 30 , Page: 5144 (55 FR 5144) , Tuesday, February 13, 1990.
This Fact Sheet is intended to raise public awareness of the potential for asbestos in or on concrete building materials at U.S. military bases and is not inclusive of all known or potential sources of asbestos.
Publication date: June 2005.
For more information, contact
Citizens for Safe Water Around Badger
E12629 Weigand’s Bay South, Merrimac, WI 53561
Phone: (608) 643-3124
Website: www.cswab.org