The Clinton administration, under intense pressure from industry, has set aside plans to list as a cancer-causing substance the fiber glass insulation used in 90 percent of U.S. homes. [1]

Four major manufacturers of fiber glass insulation have campaigned for three years to prevent their product from being labeled a carcinogen by the federal National Toxicology Program (NTP). Members of the NTP concluded unanimously in 1990 that fiber glass "may reasonably be anticipated to be a carcinogen" and were preparing to list fiber glass that way in the SEVENTH ANNUAL (1992) REPORT ON CARCINOGENS, the NTP's annual listing of cancer-causing substances. The ANNUAL REPORT is mandated by Public Law 95-622 and represents a consensus of 10 federal health agencies. [2] The International Agency for Research on Cancer (IARC), of the World Health Organization, listed fiber glass as a "probable carcinogen" in 1987.

In June of this year Mr. Clinton's Secretary of Health and Human Services (HHS), Donna Shalala, ordered a review of the National Toxicology Program's decision to list fiber glass as a carcinogen, and thus postponed publication of the SEVENTH ANNUAL REPORT. It is the first time HHS has ever called for review of an NTP decision.

Shalala's decision was a direct response to pressure from the North American Insulation Manufacturers Association (NAIMA). NAIMA hired Washington, D.C. attorney Harrison Wellford, a former "Nader's Raider" and member of the Clinton transition team who had worked with Shalala in the Jimmy Carter White House in the late '70s.

On February 25 Wellford wrote a "Dear Donna" letter in which he reminisced about their days together in the White House. Then he complained about the process by which government scientists had concluded that fiber glass causes cancer, and finally he threatened that NAIMA might take legal action if the NTP listed fiber glass as a probable carcinogen. NAIMA has four members: CertainTeed Corp.; Owens-Corning Fiber Glass Corp.; Knauf Fiber Glass GMBH; and Schuller International, Inc. (formerly Manville Co.).

Soon after Shalala received Wellford's letter, the National Toxicology Program staff prepared a response, denying his request for a re-review of fiber glass. But that letter was never sent.

In late May, representatives of NAIMA met with Donald A. Henderson, deputy assistant secretary for health and science at HHS, where they found a receptive ear.

At the same time, the industry organized a letter-writing campaign to members of Congress by employees of fiber glass manufacturing plants.

On June 9 Shalala told Wellford she was granting the delay he had asked for. Three weeks later, the industry filed a formal petition asking for the delay. The industry challenged the criteria used by HHS and NTP in determining what substances to list as carcinogens. The World Health Organization uses the same criteria.

A week after the formal petition was filed, according to the WASHINGTON POST, Donald Henderson told his staff he agreed with the industry position that the decision on fiber glass should be put to a formal vote of the NTP executive committee and that he wanted all the appropriate review committees to reconsider their decisions. Henderson is former Dean of the School of Public Health at Johns Hopkins University and is famous for organizing the program that successfully eradicated smallpox worldwide. Within HHS, he has become known for playing a role similar to that played by Dan Quayle's Competitiveness Council in the Bush administration (see RHWN #251)--an informal, behind-the-scenes court-of-last-resort where industry can appeal to modify policies and scientific conclusions that it does not like.

The carcinogenicity of fiber glass and other MMMFs [man-made mineral fibers] has been the subject of scientific and medical research for more than 20 years. In 1970, Dr. Mearl F. Stanton at the National Cancer Institute 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 it is caused by asbestos fibers. Stanton continued his research and showed that it was the size of the fibers that caused them to be carcinogenic: when glass fibers are manufactured as small as asbestos fibers, they cause cancers in laboratory animals, as asbestos fibers do. [3] Asbestos is a potent human carcinogen, which will have killed an estimated 300,000 American workers by the end of this century. [4] The finding that fiber glass causes diseases similar to asbestos was chilling news in the early 1970s, and an additional 20 years of research has not made the problem seem less serious. Workers in fiber glass and mineral wool manufacturing plants are exposed to numbers of fibers far lower than the numbers to which asbestos workers were exposed, yet several industry-sponsored epidemiological studies in the U.S., Canada, and Europe have reported statistically significant elevations in respiratory disease, including lung cancers. [5,6,7,8]

The immediate concern is for the health of manufacturing workers, and for the health of insulation installers who may have even more exposure (and in poorly-ventilated, enclosed spaces) compared to manufacturing workers. Homeowners who handle small quantities of fiber glass insulation briefly are probably in substantially less danger, though wearing a special mask capable of filtering out tiny fibers is always a good idea when handling fiber glass, mineral wool or asbestos. A longer-term concern is that all the billions of pounds of fiber glass insulation now in buildings will eventually go somewhere after the buildings deteriorate. Fiber glass--which only came into commercial use in 1940--is a very persistent substance and can now be measured at low levels on remote rural mountain tops, giving rise to a concern that humans will eventually pollute the entire atmosphere with low levels of persistent, dangerous and irritating fibers. Glass fibers buried in the ground have been measured "leaking" into the air above the surface of burial sites such as landfills. [3]

But for the present the government is only concerned about fiber glass as it affects worker health. A 1988 review of fiber glass studies by the National Institute of Occupational Safety and Health (NIOSH) concluded, "Published experimental evidence [from laboratory animals] demonstrates that fibrous glass has the same potential for inducing cancer as asbestos fibers of the same dimension. Recently published epidemiological data [from studies of exposed humans] indicates that there has been a risk of lung cancer in people employed in both the rock or slag wool and glass wool sectors of the man-made mineral fiber industry amounting to some 25% above normal 30 years after first employment. Furthermore, it is likely that man-made mineral fiber may have about the same carcinogenic potential as asbestos fibers of the same dimensions..."

Since July, 1991, the U.S. Department of Labor has required certain fiber glass products, including insulation, to carry a warning label that says, "Possible cancer hazard by inhalation."

NAIMA has challenged research findings, based on the way laboratory animals are exposed to MMMFs, such as fiber glass. When rats breathe mineral fibers in the air, their nasal passages efficiently capture the fibers and prevent them from entering the lungs. Because rats cannot breathe through their mouths (the way many children do, and the way workers exerting themselves on the job may do), fibers are injected directly into the lungs of rats to test for an effect. Medical researchers consider this appropriate, since humans breathing through their mouths can draw airborne fibers deep into their lungs. NAIMA has challenged this technique for exposing laboratory animals to MMMFs, and is thus challenging some of the fundamental practices of science, medicine and public health, internationally. It is this aspect of Donna Shalala's final response to her friends at NAIMA that will be most interesting, and most telling.
--Peter Montague, Ph.D.
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[1] Frank Swoboda, "U.S. Rethinks Calling Fiberglass Possible Carcinogen," WASHINGTON POST September 10, 1993, pg. B-1. And see: Melissa Levy, "U.S. To Review Research That Suggests Fiberglass Insulation is Carcinogen," WALL STREET JOURNAL September 13, 1993, pg. A18.

[2] The annual list of carcinogens is drawn up by an inter-agency Working Group for the Annual Reports on Carcinogens, which includes representatives from the Agency for Toxic Substances and Disease Registry (ATSDR); the Centers for Disease Control (CDC); the National Institute for Occupational Safety and Health (NIOSH); the Consumer Product Safety Commission (CPSC); the U.S. Environmental Protection Agency (EPA); the Food and Drug Administration (FDA); the National Cancer Institute (NCI); the National Institute of Environmental Health Sciences (NIEHS); the National Library of Medicine (NLM); and the Occupational Safety and Health Administration (OSHA).

[3] The early history of research on fiber glass was reviewed by Katherine and Peter Montague, "Fiber Glass," ENVIRONMENT Vol. 16 (September 1974), pgs. 6-9.

[4] Philip J. Landrigan, "Commentary: Environmental Disease--A Preventable Epidemic," AMERICAN JOURNAL OF PUBLIC HEALTH Vol. 82 (July 1992), pg. 941.

[5] L. Simonato and others, "The International Agency for Research on Cancer Historical Cohort of MMMF Production Workers in Seven European Countries: Extension of the Follow-Up," ANNALS OF OCCUPATIONAL HYGIENE Vol. 31, No. 4B (1987), pgs. 603-623.

[6] Philip E. Enterline and others, "Mortality Update of a Cohort of U.S. Man-Made Mineral Fibre Workers," ANNALS OF OCCUPATIONAL HYGIENE Vol. 31, No. 4B (1987), pgs. 625-656.

[7] Harry S. Shannon and others, "Mortality Experience of Ontario Glass Fibre Workers--Extended Follow-Up," ANNALS OF OCCUPATIONAL HYGIENE Vol. 31, No. 4B (1987), pgs. 657-662.

[8] John R. Goldsmith, "Comparative Epidemiology of Men Exposed to Asbestos and Man-Made Mineral Fibers," AMERICAN JOURNAL OF INDUSTRIAL MEDICINE Vol. 10 (1986), pgs. 543-552.

Descriptor terms: donna shalala; bill clinton; fiber glass; carcinogens; insulation; iarc; ftp; hhs; north american insulation manufacturers association; naima; harrison wellford; certainteed; owens-corning fiber glass; knauf fiber glass; schuller international; manville; donald a. henderson; who; world health organization; dan quayle; competitiveness council; mmmfs; asbestos; mearl f. stanton; niosh; studies;