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    Fiberglass: Use It With Caution!

    Published in Environ, #9 (1989), p. 17. by John Bower (Copyright 1989)

    "There is a family in Rhode Island whose exposure to fiberglass insulation has been a nightmare of physical, emotional, and financial distress. In 1986, workmen installed an air conditioning and filter system in their attic. During the construction process, the existing attic insulation was crushed and disturbed. When the workers turned on a whole-house exhaust fan, fiberglass dust was carried through the open access hatch and distributed throughout the home. Although they tried to vacuum up the mess, the dust remained imbedded in all of their possessions. Almost immediately the family of four experienced a variety of eye, ear, skin, and respiratory problems. Their physician diagnosed their ill health as being related to "acute fiberglass inhalation." Their unbelievable list of symptoms included: conjunctivitis, dermatitis, intestinal and urilogical disorders, immunological imbalances, chronic chemical sensitization, heart irregularities with accompanying chest pain, acute nervous teeth causing temporal mandibular joint syndrome, acute sinus headaches, migraine headaches, tracheitis, tonsillitis, sinusitis, tachycardia, acute eczema and psoriasis, acute depression, anxiety, and tension.

    Despite thorough cleaning, they will probably have to discard such things as carpeting, draperies, upholstered furniture, and clothing because the glass fibers are now imbedded too deeply in them. Doctors believe that because of their exposure, they have become sensitized to their home and possibly other things in the environment. They speculate that their problems might be due to the formaldehyde that was released as the resin-coated fiberglass blew throughout the house. Today their health is only marginally better. Both their own insurance company and that of the air conditioning company have denied further liability. Their health has been severely damaged and their future is filled with uncertainty and anxiety.

    Another family, on the other side of the country in Utah has experienced similar problems. In the Fall of 1979, this family of six moved into a new house. While they experienced minor symptoms at first, it was in early 1982 that the family's health really deteriorated. By then, their fifth child was born. The baby was put on antibiotics at age two and a half weeks for an eye and throat infection. The other children had constant infections and spent more time on antibiotics than off them. Symptoms included asthma, severe headaches, nausea, stomach aches, weight loss, allergies, ear infections, throat infections, lung infections, eczema, and swollen eyes. Four children had surgery to remove their severely infected tonsils and adenoids. They handled the surgery well but their health deteriorated as soon as they returned home. By now the entire family's health was in shambles. They had difficulty in getting to sleep at night and in getting up in the mornings. Their reactions were like someone who was drugged. They finally realized that the severity of their symptoms lessened when they were away from home. They assumed that something in their new house was responsible for their ill health.

    In May of 1987 they moved out. Their health immediately improved. The children began eating again and put on lost weight. Negative personality changes reversed. However, they have not returned to the state of health that they once enjoyed. Asthma, eczema, swollen lymph nodes, sinus infections, and allergies still plague them. If they reenter their home, various other symptoms return.

    Their home has been tested for organic vapors and for respirable fiberglass particles. There were high levels of glass fibers in the air that were filtering into the house from the blownin attic insulation. The fibers entered the living space through the access hatch, light fixtures and bathroom vents. Like the Rhode Island family, they have been affected not only physically, but emotionally and financially as well.

    Glass is a fairly inert product. Except for being cut by a something like a broken window pane, there is generally little about glass to make it harmful to the body. Fiberglass is simply glass that is in the shape of thin threads. Because of their small diameter, fibers of glass are very flexible. However, they can still be broken, and like a broken window, they are capable of cutting the body, although the cuts will be very small.

    Technically, fiberglass is said to be a man-made mineral fiber, as opposed to a naturally occurring mineral fiber like asbestos which is mined directly from the earth. Fiberglass is made by melting glass and drawing it out into strands. Rock wool is another man-made mineral fiber that can be used for insulation. It is made by melting rocks or slag and drawing it into threads. Rock wool is not encountered today as much as fiberglass although it has similar properties

    Fiberglass can be combined with various polyester or epoxy resins to produce such things as fishing rods, skis, sports car bodies and bullet proof vests. The combination of fiberglass and resin can be very strong. The glass tends to reinforce the resin yielding an end product that is considerably stronger than either of the original components. Raw fiberglass can also woven into fabric for use as products such as draperies. Fiberglass cloth is especially suited for fire resistant applications. In house construction, fiberglass insulation is very widely used. It can be found inside walls, floors and ceilings as well as around furnace ductwork. Another use of fiberglass that many consumers come in contact with is in air filters.

    Unlike the broken window pane, there are health concerns about fiberglass that go far beyond its ability to cut the skin. Some researchers are suggesting that it can induce cancer, in much the same way as asbestos. A few people are claiming that it is actually worse than asbestos. The effects of asbestos fibers on the body are very well documented, yet there is much controversy as to weather or not fiberglass should be placed in the same category. There is, however, a growing body of evidence that fiberglass is not as benign as was previously believed.

    Before discussing the scientific evidence, we must first look at the forms fiberglass is found in. During manufacture, fibers can be made into long continuous threads of fairly large diameter, or into shorter, smaller diameter individual strands. The long, large diameter threads are generally used in fabric, and are usually too big to become airborne. Therefore, they cannot be inhaled. They can, however, still cut the skin. The smaller fibers are of a size that can become airborne. As they float through the air, they may be inhaled. While many of these fibers are too large to get past the nose, some of the very small diameter fibers can find their way into the lungs. Fiberglass insulation tends to use smaller fibers because of their enhanced insulating ability.

    When fiberglass is combined with a resin to make an object like snow skis, it is trapped in the resin and cannot become airborne. These products are referred to as "reinforced fiberglass" products. The resins used can outgas various fumes that have been shown to bother sensitive people. If such an object is broken, sanded or otherwise abraded, airborne fibers and bits of resin can be released into the air.

    Most of the fiberglass that is used for insulation or for air filters has some sort of resin coating. This helps the product hold its shape. Insulations and filters only contain a minimal amount of resin, so fibers can break off and float around the air relatively easily when they are handled. Instead of being simply fiberglass particles, they are resin coated fiberglass particles. Sometimes, fiberglass insulations or fiberglass air filters can contain oils or other materials.

    Health effects of fiberglass can be related to either the glass fibers themselves or to the resin or oil that coats the fibers. As fibers float through the air, they can pick up an electric charge. Some researchers believe that this may also have an effect on how the fibers react with the body.

    In a 1977 literature review that appeared in the Annals of Occupational Hygiene, J.W. Hill discussed the health effects that were known at that time. The most obvious effect of fiberglass is on the skin. It produces very small cuts which result in itching and redness. Anyone who has worked with fiberglass insulation will attest to the fact that this happens rather quickly. Hill noted that a skin "sensitization" may occur, but that it would probably be associated with the resins used. He also discussed the fact that fiberglass can result in upper respiratory tract irritation. However, he could find "no evidence of disease attributable to" fiberglass. He noted that in animal experiments, "glass fibers produce minimal tissue response in the lungs." In summary, this paper did not find fiberglass to be a serious problem. However, more recent studies have noted some alarming possibilities.

    Several researchers are now of the opinion that the cancer causing ability of a respirable fiber is related to its size, rather that its chemical composition. Since many small glass fibers that people are being exposed to are in the same size range as asbestos, there is cause for concern. The fiber size that seems to have the greatest potential for carcinogenicity ranges from 0.5 to 2.5 micrometers in diameter and 10 to 80 micrometers in length.

    While fiber size may be important, it should be noted that fiberglass and asbestos are two entirely different minerals with different properties. For example asbestos fibers can split along their length into smaller diameter fibers while fiberglass cannot. These smaller diameter fibers are more easily inhaled. When asbestos is deposited in the lung it remains intact for life. If fiberglass comes in contact with lung tissue, the bodily fluids will slowly begin to dissolve. Unfortunately, as it dissolves, it may produce silicic acid, which is toxic to living cells.

    All fiberglass products probably contain some fibers in the small respirable size range, but there is one particular product that contains a very high percentage of these potentially dangerous sized fibers. The residential insulation INSUL-SAFE III that is manufactured by the Certainteed Corporation, contains over 80% of fibers in this range. It is a white product, resembling cotton, that is usually installed by blowing it in place with a machine. It contains no resin binder. INSUL-SAFE III does, however, contain a small amount (less than 1%) of mineral oil and silicone. Of all the residential insulations available, this product is the least contaminated from the standpoint of resin or oil. As such, it may not bother individuals with chemical sensitivities in the way fiberglass batt insulations do. All residential fiberglass batt insulations contain approximately 5% resin binder but they have fewer of the small sized fibers.

    In October of 1986, papers at a World Health Symposium in Copenhagen showed that workers in fiberglass manufacturing plants suffered an excess of fatalities from lung cancer. In an article in the American Journal of Industrial Medicine, John R. Goldsmith, MD summed up the current research by stating that fiberglass has "been shown by industry-sponsored studies in Europe and the United States to be associated with possibly increasing risk of mortality from lung cancer and chronic pulmonary disease."

    There are now studies that show a relationship between exposure to glass fibers and bronchitis, nonmalignant respiratory disease, and upper respiratory and alimentary tract cancers. These studies have been done with factory workers who, surprisingly, are exposed to relatively low levels of airborne fibers. Often, insulation installers are exposed to higher levels of fiberglass in the air than are factory workers, and the two examples at the beginning of this article show that homeowners can sometimes be exposed to unusually high levels.

    Experiments with rats have demonstrated a clear relationship between cancer and fiberglass when the fibers are surgically implanted, but not when they are inhaled. Industry representatives concede that surgical implantation is indeed a cause of cancer, but suggest that the studies showing a relationship between inhaled fibers and factory workers are invalid. Actually, the research against fiberglass is not nearly as damaging as that against asbestos, however, cancer develops slowly, and fiberglass has not been in widespread use as long as asbestos.

    Because of conflicting research, some scientists believe that it is better to be safe than sorry. Epidemiologist Philip Enterline, who has studied the link between cancer and fiberglass, believes that it should be "treated like asbestos." The federal government, however, has yet to place restrictions on it. In fact, there are some local building codes that actually require that fiberglass be used to insulate the inside of heating ducts. This location for insulation is very undesirable because the glass fibers can easily break off and enter the airstream, where they will eventually be inhaled by the occupants.

    Fiberglass insulation manufacturers are required by law to list possible health effects on Material Safety Data Sheets. Recently, they have been revising these sheets to indicate that industrial workers first employed more than 30 years ago in the manufacture of fiberglass have a slightly higher rate of lung cancer than the general population.

    Most of the recent research and concern has concentrated on the cancer causing ability of fiberglass. As with most pollutants, cancer is always singled out as THE disease to be aware of. Unfortunately, there are many ways that pollutants can affect health. For example, outgassing of organic chemicals is an immediate health concern for a growing segment of the population that is chemically sensitive.

    Residential fiberglass batt insulation contains about 5% resin binder that is capable of outgassing formaldehyde fumes into the air. The pink colored insulation manufactured by Owens-Corning Fiberglas Corporation contains, in addition, about 1% dye that has its own outgassing characteristics. The resin used in insulation is usually a phenol-formaldehyde product, but Manville Corporation uses a urea-extended phenol-formaldehyde resin, which outgasses at a faster rate. Of the major insulation manufacturers, the batt insulation produced by Certainteed Corporation, with 4% phenolformaldehyde resin and no dye, is probably the least potent from an outgassing standpoint, however, it can still bother people sensitive to formaldehyde.

    When resin coated fiberglass enters the sinuses or the lungs, there is the possibility that the resin could react with the soft tissues and cause inflammation or damage. It could also affect the immune system. It is known that formaldehyde based resins decompose when exposed to heat and humidity, yet no research has been done to explore this mode of exposure.

    What should you do if your home is insulated with fiberglass insulation? Most researchers don't believe that it presents enough of a problem to warrant removal, but the two case histories outlined above attest to the fact that severe and lasting problems can result from exposure to residential fiberglass insulation. In most installations, the insulation will stay where it is placed in the attic, walls or floor and will cause no problems. The tighter the house is constructed, the less likely that any glass fibers or formaldehyde fumes will migrate into the living space.

    If health problems are suspected to be related to insulation, the air in the house should be tested by a reputable firm. Removal of the insulation should only be attempted as a last resort because it is messy, costly, and could result in greater contamination of the house. A better solution would be to caulk and tape shut the pathways through which the insulation is entering the living space.

    If you are working with fiberglass insulation, it is important to wear protective clothing such as long sleeves and gloves. A dust mask and/or activated charcoal mask is also recommended. Clothing should be laundered separately to avoid contaminating other garments.

    In new installations, it is a good idea to totally separate the insulation from the living space. This can be done by sealing all openings in the walls around electrical outlets, windows, etc. Foilbacked drywall can be used to insure that formaldehyde fumes do not migrate into the house. The result may be a house that needs a fan or other mechanical device to introduce fresh air, but this is preferable to breathing glass fibers and fumes outgassed by the resin binder. Uncontrolled infiltration means that air passes through walls, possibly bringing with it resin coated glass fibers.

    It is often necessary to insulate heating and air conditioning ducts. In order to avoid contaminating the airstream, this should always be done on the outside of the ducts. It is also a good idea to tape all of the seams in the ductwork prior to adding the insulation so the fibers or formaldehyde fumes cannot enter.

    An often overlooked source of indoor air pollution involves fiberglass air filters. Most contain some type of resin or oil that can bother sensitive people. These materials are often added to the fiberglass to enhance its dust grabbing ability. Unfortunately, they can outgas minor amounts of fumes into the fresh air stream. This can be a problem with even the most expensive air filters.

    While they may be effective in removing dust, their outgassing actually adds other pollutants to the air. For this reason, selecting a tolerable air filter is often a problem for sensitive people.

    The current cancer research on fiberglass is not nearly as overwhelming as the evidence on asbestos and it may never be. However, that doesn't mean that fiberglass is totally safe. There are probably more than the two families mentioned above who have experienced devastating symptoms. For them, cancer may not be present, at least not yet, but there are negative health effects nonetheless. While some industry spokesmen deny the dangers to the general public, there are others who consider fiberglass to be a very serious threat. It may be years before the final verdict is in.

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