* Fibreglass: a carcinogen that's everywhere &amp&amp

By Peter Montague
An industrial process for making glass fibres was first patented in Russia in 1840. At the Columbian Exposition in Chicago in 1893, Edward Libbey exhibited lamp shades, a dress, and other articles woven from glass fibres. In 1915, the Allied forces blockaded Germany, creating an asbestos shortage which resulted in commercial production of fibreglass in the US, as an asbestos substitute. In 1938, the Owens Corning Fiberglas Company was formed, and three years later, in 1941, evidence of pulmonary disease was reported by Walter J. Siebert, who investigated the health of workers in cooperation with Owens Corning. That same year another investigator reported finding "no hazard to the lungs" of workers exposed to glass fibres in the air. Scientific disagreement of this sort has characterised the study of fibreglass ever since; meanwhile fibreglass production has increased steadily.
That same year (1941), the US Patent Office issued patents for 353 glass wool products. Glass wool, fibreglass, fibreglas, fibrous glass and glass fibres are all names for the same thing: thin, needle-shaped rods of glass.
Fibreglass is now used for thermal insulation of industrial buildings and homes; as acoustic insulation; as fireproofing; as a reinforcing material in plastics, cement and textiles; in automotive components; in gaskets and seals; in filters for air and fluids; and for many other miscellaneous uses. More than 30,000 commercial products now contain fibreglass.
As asbestos has been phased out, fibreglass production has been rising. In 1975, US production of fibreglass was 247.88 million kilograms; by 1984 it had risen to 632.88 million kilograms. If that rate of growth (10.4% per year) held steady, production of fibreglass in the US in 1995 would be 1980 million kilograms.
Fibreglass is now causing serious health concerns among US officials and health researchers. In a series of papers published from 1969 to 1977, Dr Mearl F. Stanton of the National Cancer Institute found that glass fibres less then 3 microns in diameter and greater than 20 microns in length are "potent carcinogens" in rats; and, he said in 1974, "it is unlikely that different mechanisms are operative in man".
Since that time, studies have continued to appear showing that fibres of this size not only cause cancer in laboratory animals, but also cause changes in the activity and chemical composition of cells, leading to changes in the genetic structure and in the cellular immune system. Although these cell changes may be more common (and possibly more important) than cancer, it is the cancer-causing potential of glass fibres that has attracted most attention.
In 1970, Dr Stanton announced that "it is certain that in the pleura of the rat, fibrous glass of small diameter is a potent carcinogen". The pleura is the outer casing of the lungs; cancer of the pleura in humans is called mesothelioma and is caused by asbestos fibres.
Stanton continued his research and showed that when glass fibres are manufactured as small as asbestos fibres, glass causes cancer in laboratory animals just as asbestos does. Asbestos is a potent human carcinogen, which will have killed an estimated 300,000 US workers by the end of this century.
The finding that fibreglass causes diseases similar to asbestos was chilling news in the early 1970s, and an additional 25 years of research have not made the problem seem less serious. Workers in fibreglass manufacturing plants are exposed to concentrations of fibres far lower than the concentrations to which asbestos workers were exposed, yet several industry-sponsored epidemiological studies of fibreglass workers in the US, Canada, and Europe have reported statistically significant increases in lung cancer.
The International Agency for Research on Cancer (IARC) of the World Health Organisation listed fibreglass as a "probable [human] carcinogen" in 1987. In 1990, the members of the US National Toxicology Program (NTP) — representatives of 10 federal health agencies — concluded unanimously that fibreglass "may reasonably be anticipated to be a carcinogen" in humans. NTP members were preparing to list fibreglass that way in the Seventh Annual (1992) Report on Carcinogens, the NTP's annual listing of cancer-causing substances, but industry intervened politically.
Four major manufacturers of fibreglass insulation campaigned for three years to prevent their product from being labelled a carcinogen by NTP. They managed to delay the publication of the NTP's Seventh Annual Report on Carcinogens for more than two years, but on June 24, 1994, the secretary of Health and Human Services, Donna E. Shalala, signed the report and sent it to Congress, thus making it official policy of the US government that fibreglass is "reasonably anticipated to be a carcinogen". In the US, fibreglass must now be labelled a carcinogen.
Announcing this decision, government officials tried to play down its significance. Bill Grigg, a spokesperson for the US Public Health Service (a subdivision of Health and Human Services), told the Washington Post, "There are no human data I'm aware of that would indicate there's any problem that would involve any consumer or worker".
To make such a statement, Grigg had to ignore at least six epidemiological studies showing statistically significant increases in lung cancer among production workers in fibreglass factories. Indeed, according to researchers in the Occupational Safety and Health Administration (OSHA, another division of Health and Human Services) fibre for fibre, fibreglass is a more potent carcinogen than asbestos.
Fibreglass — a material that nature does not make — is now measurable everywhere in the air. The air in cities, rural areas and remote mountain tops now contains measurable concentrations of fibreglass.
According to OSHA researchers, an eight-hour exposure to 0.043 glass fibres per cubic centimetre of air is sufficient to cause lung cancer in one in 1000 exposed workers during a 45-year working lifetime.
In rural areas, the concentration of fibreglass in outdoor air is reported to be 0.00004 fibres per cubic centimetre, about 1000 times below the amount thought to endanger one in 1000 fibreglass workers. But people in rural areas breathe the air 24 hours a day, not eight. Furthermore, a human lifetime is 70 years, not the 45 years assumed for a "work lifetime".
Moreover, one in 1000 is not adequate protection for the general public; the US Environmental Protection Agency uses one in 100,000 or one in a million as a standard for public exposures. (And in urban air, there's 10 to 40 times as much fibreglass as in rural air.) Therefore, the amount of fibreglass in the outdoor air in the US and Europe (and presumably elsewhere) already seems higher than prudent public health policies would permit.
It has been 25 years since researchers at the National Cancer Institute concluded that fibreglass is a potent carcinogen in experimental animals. During that time, additional research has confirmed those findings again and again. During the same period, the amount of fibreglass manufactured has increased rapidly year after year.
Ninety per cent of US homes now contain fibreglass insulation. All of this fibreglass will eventually be released into the environment unless special (and very expensive) precautions are taken to prevent its release. We believe the likelihood of such precautions is nil. Billions of kilograms of fibreglass now in buildings will eventually be dumped into land fills, from which it will leak out slowly as time passes. Elevated concentrations of fibreglass are already measurable in the air above land fills today.
In 1991, Patty's Industrial Hygiene and Toxicology, a standard reference book on workplace safety and health, said about fibreglass, "... it is prudent for industrial hygienists to treat these materials with the same precautions as asbestos". In the US, all new uses of asbestos have been banned. A ban on fibreglass is long overdue.
[From Rachel's Environment & Health Weekly.]