Concern about the presence of asbestos in buildings, including schools, is widespread. Because prolonged exposure to high levels of asbestos has been linked with such diseases as asbestosis, lung cancer and mesothelioma, there appears to be a general public attitude that any asbestos in schools or other buildings represents an immediate threat to human safety. Unfortunately, this attitude has often led to hasty, unnecessary and even dangerous asbestos removal activities.
In fact, the real issue is identifying the few buildings where significantly damaged asbestos-containing materials might pose a risk of very high asbestos exposures to occupants. Therefore, the key challenge facing those responsible for dealing with the asbestos issue is understanding the facts and making scientifically-sound decisions.
The Safe Buildings Alliance shares the public's concern for safe, appropriate and timely action regarding asbestos in buidlings. To help you understand this important issue, the Alliance has developed this bookle. It describes available scientific knowledge concerning asbestos in buildings and provides answers to the important questions.
The Safe Buildings Alliance is an incorporated association of manufacturers that previously supplied asbestos-containing materials for building construction. Alliance members are aware of and sensitive to the public's concern and need for accurate information on this emotional and often misrepresented issue. Along with other concerned citizens, community leaders and government officials, Alliance members are advocating:
A. There has been confusion about which materials contain asbestos. Building owners concerned about the presence of asbestos should first take core samples of friable products suspected of containing asbestos. These should be analyzed by polarized light microscopy or X-ray diffraction, or both, to determine their content. Competent laboratories capable of making such analyses can be found in major cities.
A. Because the mere presence of asbestos-containing materials creates no hazard, building owners should determine whether asbestos-containing products are releasing fibres. The best way of finding what exposures exist is to monitor airborne asbestos levels. Given the extremely low levels of asbestos typically found in buildings, it is difficult to get accurate air level readings. Only experts are qualified to make such determinations.
A. Independent experts believe that in most cases asbestos exposure can be properly controlled by a combination of minor patching or repairs, improved custodial control and special maintenance procedures. (16,20,30) Where small areas of asbestos-containing materials have been damaged such that fibre release may be possible, simple patching with readily available commercial compounds will reseal the asbestos fibres. Such procedures can be applied, for example, to cementitious ceiling materials and pipe and boiler insulation.
Easily implemented maintenance procedures are also effective in controlling exposure to asbestos fibres. Custodial personnel should know the location of asbestos-containing materials and be instructed in the use of wet cleaning and other methods (including proper disposal). In some cases, HEPA vacuum cleaners should be used to properly clean up asbestos fibres.
Building managers also should ensure that maintenance workers, such as electricians or plumbers, do not inadvertently disturb asbestos-containing materials and that they use proper work practices when such materials are involved.
Combined with periodic inspection, these simple precautionary measures can simply and inexpensively protect both building occupants and workers from asbestos exposures of concern.
A. In those rare circumstances where airborne fibre concentrations are very high and cannot be lowered by the simple custodial and maintenance procedures discussed above, other control techniques may be appropriate. Encapsulation for some products using commercially available sealants or coatings (particularly those studied and recommended by the Battelle Institute in a study sponsored by the U.S. Environmental Protection Agency [EPA]) can be an effective control measure, as can enclosure of asbestos-containing materials in some circumstances. Removal the method recommended by most asbestos abatement contractors should be used as a last resort. There are few qualified contractors who will assure a safe removal and disposal. Also, removal is the most costly method in terms of meeting established EPA and U.S. Occupational Safety and Health Administration (OSHA) regulatory standards, and, most importantly, removal often results in increased fibre release, even when careful work practices are followed.(15,21)
A. Yes. Many experts believe that removing asbestos-containing materials in buildings often does more harm than good. (9,17,19,30) Very recently, the New Jersey Department of the Pubic Advocate reported that:
Improper asbestos removal places workers, building occupants, teachers and especially children at risk of serious health injury. It is well documented that the improper removal of asbestos can be far more hazardous than if the asbestos is not removed at all.(16)
Very few contractors are qualified to conduct removal work properly, and the demand for their services far outweighs the few available qualified contractors. Many independent experts who have studied the situation have found asbestos fibre levels in buildings to be higher after materials were removed that before removal:
The Congressionally-chartered National Institute of Building Sciences reached similar conclusions:
There is some evidence to indicate that removal of asbestos-containing building products from schools and other facilities may be counterproductive. Whether the removal process involves dry or wet disruption of the in-place asbestos, data shows that a substantial quantity becomes resuspended and recirculated throughout the building. Following removal, weeks and sometimes months must pass before ambient air levels of friable (crumbling) asbestos fibre drop below acceptable levels.(26)
A. The mere presence of asbestos-containing materials in a building is no cause for alarm. Everyone is exposed to asbestos every day from a variety of sources. While high levels of asbestos exposure, such as those experienced by workers years ago, can sometimes lead to serious disease, the low levels found in the ambient atmosphere and in some buildings should not be a cause for concern.
Once an expert laboratory has confirmed the presence of asbestos-containing materials, building owners need to obtain qualified independent advice specific to their building. In most cases, a simple and inexpensive program of patching and special custodial and maintenance procedures will keep asbestos levels under control. Removal of asbestos-containing materials should be a last resort, primarily because of the high likelihood that asbestos fibre levels will be increased after materials are removed.
The widespread natural occurrence of asbestos
A. The term "asbestos" refers to a unique group of minerals that are widely useful because of their special properties. Asbestos minerals are fibrous silicates with a crystalline structure and are found in rock formations throughout the United States and the world.(31) However, concentrations high enough to make commercial mining practical exist only in certain locations. As a result of both natural occurrence and commercial use, asbestos is commonly found throughout the United States in water supplies and in outside and indoor air.
A. Human exposure to asbestos may be caused by air, wind and water erosion from naturally-occurring deposits as well as by the mining, manufacture and use of some asbestos-containing products. Asbestos concentrations exceeding those permitted by the government in workplaces have been recorded in natural dustfall along roads in some areas.(4) Drinking water areas of asbestos-containing rock has been found to contain hundreds of millions of naturally-occurring asbestos fibres per liter.
A. People are regularly exposed to asbestos. The U.S. Environmental Protection Agency, in broad samples of local water supplies, detected naturally-occurring asbestos in nearly three-fourths of all U.S. water systems. More than 15 percent had greater than one million fibres per litre (or more than 250,000 fibres per eight-ounce glass).(11) The U.S. Department of Health, Education and Welfare reported that in 20 U.S. cities, airborne asbestos concentrations ranged up to 0.007 fibres per cubic centimeter (fibres/cc) and averaged 0.0006 fibres/cc.(6) Very recently, the National Academy of Sciences concluded that the average outside air concentration throughout the United States is 0.0004 fibres/cc.(13) What these rather complex figures mean simply is that people are exposed daily to asbestos without developing asbestos-related diseases.
A. Asbestos exposure is unavoidable, given its widespread natural occurrence in air and water. Asbestos fibres have been found in lungs and other tissues of the general population. Analyses of normal healthy adult lung tissues from persons who have not been exposed in the workplace have found that average lungs contain millions of asbestos fibres.(3) These findings indicate how pervasive asbestos is in our environment. Eliminating all exposure to asbestos is impossible.
A. Because
the concentration of asbestos fibres occurring in the environment generally is at low levels, numerous governmental and scientific groups, including the National Academy of Sciences, Commission of European Communities, and the International Agency for Research on Cancer, have concluded that low level exposures do not pose significant public health risk. While not concerned about low, everyday asbestos exposures, these groups have advocated stringent workplace controls on asbestos minings, manufacture and product installation, where much higher exposures can occur.(2,7,10,12,14,20)
In the case of schools and other buildings, the EPA has yet to make a clear determination of what potential exposures exist and whether scientific information indicates such exposures pose any significant public health risk.
Uses of asbestos
A. For many years, asbestos was called the magic mineral because of its unique nature and widespread usefulness. The word itself comes from the Greek word for incombustible. The mineral's fire retardant qualities are among its most valuable characteristics. This led to its wide use in ships, buildings and theater curtains, where protection against fire was essential. In addition to its fire retardant properties, it has other qualities which make it useful, including: a fibrous nature, heat stability, thermal and electrical resistance, flexibility, high tensile strength and stability in acids or alkalis.(31) Untold thousands of lives have been saved by the use of asbestos.
A. Asbestos has been used extensively. Asbestos consumption jumped dramatically in the United States during World War II, because of the Navy's determination that it was an essential component of shipboard fire protection.(32) Up until 1976, it was required by model building codes in specific areas of buildings where protection against fire was essential. In 1973 and agin in 1978, however, the EPA prohibited certain spraying of asbestos-containing materials as part of its air pollution regulations.(8)
A. Because of its unique properties, asbestos is currently used in hundreds of products including vehicle brakes, roof shingles, building panels, water and sewer pipes, roof coatings, floor tiles, electrical insulating materials, specialized thermal insulation, elevator brakes, and protective aprons and gloves.
A. No. The presence of an asbestos-containing material will not, of itself, pose any hazard to building occupants. No risk occurs unless a significant number of respirable asbestos fibres are released from the material and enter the building air supply. The Environmental Protection Agency, in a document entitled Sprayed Asbestos-Containing Materials in Buildings, has found that most asbestos products "have effectively immobilized the asbestos fibres by mixing them into a strong binding material."(22)
A. The following table indicates the purpose and general location of such product types.
| Product type | Purpose | Generally found |
| Acoustical | Sound control | Ceilings in classrooms, halls, multi-purpose rooms |
| Thermal insulation | Safety-energy conservation | Pipes and boilers |
| Steel fireproofing | Fire protection | Covering structural steel |
| Asbestos cement board | Fire protection | Near furnaces and boilers |
| Tile and sheet flooring | Cleanability-decor | Floors, classrooms and halls |
| Textiles | Fire protection | Auditorium curtains, laboratory aprons and gloves |
A. Most concern about asbestos in buildings relates to certain materials that release fibres in large quantities. Over the years asbestos-containing products have been classified as both cementitious and dry-applied materials. Cementitious products are less likely to release fibres because they are bonded into non-asbestos materials. Dry applied materials are not as well-bonded into other materials. As a result, they can have a higher potential for fibre release when disturbed.(20) Even such potentially friable materials will not normally release fibres in significant numbers if they are undamaged, well-maintained or wrapped in protective coverings.
A. Numerous studies, including those conducted by the EPA and the Ontario Royal Commission, have monitored asbestos levels in buildings constructed with these materials. In many cases, airborne levels have been so low as to be indistinguishable from outside air. In some, measurements show levels that exceed outside air levels by small amounts, and in only a few, measurements have significantly exceeded outside levels. But even at the highest levels, exposure is substantially lower than the Occupational Safety and Health Administration standars.(1,18,19,24) The Ontario Royal Commission concluded the "majority of exposures of building occupants in buildings with substantial amounts of friable asbestos would be to fibre levels less than 0.001 f/cc (fibre/cc), with a few single readings as high as 0.01 f/cc representing the highest likely exposure."(20)
A. Exposure levels in a typical building with asbestos-containing materials are tens of thousands of times less than historical asbestos worker exposures, as illustrated in the table below.
It is highly unlikely that building exposure levels will rise as high as present OSHA standards for the workplace and most certainly not as high as levels associated with historical asbestos worker exposures.
| Representative average asbestos exposures | |
| Unregulated workplaces (historical) | 20 or more f/cc |
| Workplaces today | Up to 2.0 f/cc |
| Typical building with asbestos-containing materials | Up to 0.0009 f/cc |
| High outside air readings | 0.0007 f/cc |
| Outside air | 0.0004 f/cc |
A. No, because cumulative exposures are also very low. As the following table illustrates, a representative lifetime exposure from outside air would be 20 times higher than exposure over 10 years in a school building. The school building exposure would be but 1/100,000th, or 0.001%, the exposure that a typical worker has been found to have in an historical asbestos workplace.
| Level in
fibres/cc | Years of exposure | Days/ week | Hours/ day | Weeks/ year | Total lifetime* fibre hours |
|
| Unregulated workplaces (historical) | 20 | 30 | 5 | 8 | 50 | 1,200,000 |
| OSHA Standard | 2 | 45 | 5 | 8 | 50 | 180,000 |
| Proposed OSHA standard | 0.5 | 45 | 5 | 8 | 50 | 45,000 |
| Outisde air | 0.0004 | 70 | 7 | 24 | 52 | 245 |
| Typical school with asbestos-containing materials | less than 0.0009 | 10 | 5 | 6 | 36 | Less than 11 |
* Scientists often express cumulative asbestos exposures in fibre-years; one fibre-year of exposure can be caused by one year exposure at 1 fibre/cc or 10 years exposure at 0.1 fibres/cc.(20) The table expresses the same concept, but in terms of hours of exposure for ease of understanding the comparisons.
Even in that rare school where exposures might average 0.01 asbestos fibres/cc, a student attending for 10 years would experience a total of 108 lifetime fibre hours less than one-half the exposure typically received over a lifetime breathing outside air.
A. Asbestos-containing products were most widely used in school construction from the period immediately following World War II to the early 1970's. These products were used to ensure safety and often were mandated by building codes and municipal regulations.
A. No. Some activities that disturb asbestos, especially removal, can cause high fibre release and consequent human exposure. Numerous studies have found airborne asbestos levels in buildings to be higher after removal activities than before.(1,17,19) The Congressionally-chatered National Institute of Building Sciences recently reported on cases where removal increased the risks:
[S]ome poorly performed asbestos removal and abatement work actually led to increased airborne asbestos levels in the building. There were also reports of cases where stable asbestos was disturbed during abatement resulting in airborne asbestos where it had not been previously... [I]t is clear that poor abatement practices may exacerbate existing conditions rather than solve the problem.(15)Robert N. Sawyer, M.D., one of the country's recognized experts on asbestos risks and corrective actions, recently warned the EPA:
In contrast to the nonexistent or negligible exposure of typical building occupants, removal operations are certain to disturb asbestos-bearing materials and release significant numbers of fibres... Unqualified contractors and untrained workers are more likely to aggravate the risk than to correct it.(30)
A. Yes. Many current contracts for asbestos removal call for achieving post-removal exposure levels below 0.01 fibres/cc. Because almost all buildings have even lower levels before removal, the potential for causing contamination is high.
A report issued by the State of New Jersey Department of the Public Advocate concluded: "It is well documentated that the improper removal of asbestos can be far more hazardous than if the asbestos is not removed at all."
Further, the report stated that any proposal for removal, containment or management of asbestos, "must also ensure that the short-term solution of immediate removal of asbestos does not create even greater dangers for the children in our schools."(16)