Health House News Basics Victims Resources

IARC reclassification of man-made vitreous fibers

This fall, a special committee commissioned by the International Agency for Research on Cancer (IARC) completed a re-evaluation of the cancer hazard of synthetic mineral fibers, such as fiberglass.  The panel concluded that the cancer risk from fiberglass is "not classifiable."  This reverses an action taken in 1988, in which IARC concluded that fiberglass was a "possible" human carcinogen.  

This subtle nuance in language meant a lot to the fiberglass industry, which has spent millions of dollars Euro-schmoozing over the past decade.  We expect the industry to launch a full-court press to get the United States Department of Health and Human Services to reverse its 1994 finding that fiberglass is a "probable" human carcinogen.  We can only hope the U.S. process will be more transparent than the secretive IARC special committee.

An early Owens Corning corporation press released boasted of the role one of its main scientific flacks played in the IARC re-evaluation.  That release has since been removed from the web.

IARC press release on reclassification of man-made vitreous fibers


IARC MONOGRAPHS PROGRAMME RE-EVALUATES CARCINOGENIC RISKS FROM AIRBORNE MAN-MADE VITREOUS FIBRES

A scientific working group of 19 experts from 11 countries convened by the Monographs Programme of the International Agency for Research on Cancer (IARC) has concluded its re-evaluation of the carcinogenic risk of airborne man-made vitreous fibres.

Man-made vitreous fibres in the form of wools are widely used in thermal and acoustical insulation and in other manufactured products in Europe and North America. These products, including glass wool, rock (stone) wool, and slag wool, have been in use for decades and have been extensively studied to establish whether fibres that are released during manufacture, use, or removal of these products present a risk of cancer when inhaled. Epidemiologic studies published during the 15 years since the previous IARC Monographs review of these fibres in 1988 provide no evidence of increased risks of lung cancer or of mesothelioma (cancer of the lining of the body cavities) from occupational exposures during manufacture of these materials, and inadequate evidence overall of any cancer risk.

Beside this, much industrial effort has gone into development of newer materials that have similar insulation properties to the older products, but which disappear from body tissues much more rapidly. The reason for this effort is that asbestos, a known human carcinogen which causes both mesothelioma and lung cancer and had been used as insulating material for several decades, is extremely slow to decompose and disappear from body tissues in which it has been deposited. This characteristic, known as high biopersistence, is correlated with the high carcinogenic potency of asbestos fibres. Some of these newer materials have now been tested for carcinogenicity and most are found to be non-carcinogenic, or to cause tumours in experimentals animals only under very restricted conditions of exposure.

The Monographs working group concluded that only the more biopersistent materials remain classified by IARC as possible human carcinogens (Group 2B). These include refractory ceramic fibres, which are used industrially as insulation in high-temperature environments such as blast furnaces, and certain special-purpose glass wools not used as insulating materials. In contrast, the more commonly used vitreous fibre wools including insulation glass wool, rock (stone) wool and slag wool are now considered not classifiable as to carcinogenicity to humans (Group 3). Continuous glass filaments, which are used principally to reinforce plastics, are also considered not classifiable as to carcinogenicity to humans.

For further details of the Monographs evaluation, consult http://monographs.iarc.fr, under "Agents most recently evaluated," or inquire by e-mail to grosse@iarc.fr.

For further details of current research at IARC on man-made vitreous fibres, inquire by e-mail to boffetta@iarc.fr.

For more general information, contact Dr Nicolas Gaudin, Chief, Communications (gaudin@iarc.fr).

FIN's questions for IARC

Dear Dr. Grosse:

Thank you for your reply. I do concur that IARC's charge is to investigate cancer, and I do appreciate the opportunity to ask some specific questions about the re-evaluation. They are as follows.

1. Who are the 19 experts from 11 countries on the re-evaluation panel, and what are their affiliations? If these persons are associated with a particular corporation, please provide the name of the corporation and their specific title within that organization.

2. Your press release specifically states that mineral fiber products "have been extensively studied to establish whether fibres that are released during manufacture, use, or removal of these products present a risk of cancer when inhaled." Although it has been established that installation and removal operations create airborne fiber counts far in excess of what has been recorded in a manufacturing situation, I know of no studies concerning the health or mortality of persons involved in installation or removal of MMVF insulation. Please cite the scientific basis for this statement in the IARC press release.

3. What new, independent scientific research has been offered to support the statement in the IARC press release that "Epidemiologic studies published during the 15 years since the previous IARC Monographs review of these fibres in 1988 provide no evidence of increased risks of lung cancer or of mesothelioma..."? Please provide full citations. If the study is available on the internet, please provide a URL. If the study was funded by the MMVF industry, please explain how IARC ensures that the study is free from bias.

4. If the studies mentioned above provide "no evidence" of increased cancer risk, how is that interpreted to cause IARC to lower the risk rating? Is a lack of evidence now considered evidence to the contrary? What has occurred to invalidate the original scientific reasoning behind the 1988 IARC classification?

5. Hamsters forced to breathe fine fiberglass in a Swiss laboratory did experience mesothelioma only six months into a two year study, according to documents released to the US Environmental Protection Agency. This study, funded by the MMVF industry, was apparently cancelled shortly thereafter. At least, I have never been able to locate the final documentation. Was this study reviewed by IARC? If not, why not? Is cancelling a study which is not yielding favorable results considered reasonable by IARC? (Citation: McConnell, Ernest E: Overview of the Pathology Results (Through 6 Months) of the NAIMA-supported Chronic Inhalation Study of Amosite, MMVF 10a Glass Insulation Wool and MMVF 33, a special Purpose Glass Fiber, in Hamsters. EPA document # 8EHQ-0296-13595; and letter from Ken Mentzer and supporting documents, doc. #8EHQ-0496-13595.)

6. A study at the Institute of Occupational Medicine in Edinburgh, Scotland, also produced mesotheliomas and other cancer tumors when inhaled by rats. The author of this study was James Jarvis. Was it considered? If not, why not? (Sorry, no full citation here, but I would love to locate the study if you know how.)

That's all for now. I look forward to your response. I was not able to access the full monograph on your web site. The link from the press release is either broken or there is a problem with the server.

Thank you.

Sincerely,
Robert Horowitz
Fiberglass Information Network (FIN)

Note:  As of 4/24/02, IARC has not responded to our questions.

Looking beyond IARC and cancer

IARC has examined the cancer risks in the manufacturing environment and determined that they don't know whether there is a risk.  That does not mean the risk does not exist.  That does not mean there is no risk for installers or demolition teams.  That does not mean that homeowners who are exposed to fiberglass due to a faulty installation will not get sick.

IARC is very much an "ivory tower" institution, with an arcane and impenetrable bureaucracy.  We can't tell whether they have been unduly influenced by the fiberglass industry, because we don't know who IARC talks to, and we don't know who was on the special committee.  Furthermore, neither FIN nor the general public was invited to give either written or verbal testimony.

IARC only considers cancer.  Most of the people who contact FIN are not suffering from cancer.  They are suffering from asthma- and allergy-like symptoms which have been linked, anecdotally or better, to exposure to fiberglass.  The most severe cases are debilitating and do not go away once the fiberglass is removed.

Cancer rates of fiberglass workers are marginally higher than the general public according to the major epidemiological studies.  The interpretation of these studies is open to debate, as is the way the studies have been structured.

The rat inhalation studies favored by industry are no better than the implantation studies the industry eschews.  Rats and hamsters can only breathe through their nose, and have evolved an effective particle filtration system over the years.  Humans breathe through the mouth and the nose.  Our more powerful breathing apparatus is capable of sucking in more, larger, fibers deeper into our lungs.

IARC should commission research on the following:

  • If fiberglass breaks down into the lungs, what does it break down into, and is that toxic to some organ other than lungs?  This applies not only to the glass, but also to the highly toxic phenol-formaldehyde resins used as binding agents on most fiberglass.
  • When old, filthy fiberglass enters the lungs, does that not provide a way for mold, feces and other potential disease-causing agents to penetrate very deeply into the lungs?  What are the health ramifications of demolition work where fiberglass is present?


Go to FIN Home Page
FIN--the Fiberglass Information Network-- Service to the on-line community since 1995.
 Special thanks to Sustainable Enterprises.
Please see our disclaimer.