=======================Electronic Edition========================
RACHEL’S ENVIRONMENT & HEALTH WEEKLY #444
—June 1, 1995—
News and resources for environmental justice.
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FIBER GLASS: A CARCINOGEN THAT’S EVERYWHERE
An industrial process for making glass fibers was first patented
in Russia in 1840. [1, pg.292] At the Columbian Exposition in
Chicago in 1893, Edward Libbey, an American, exhibited lamp
shades, a dress, and other articles woven from glass fibers. In
1915, the Allied Forces blockaded Germany, creating an asbestos
shortage which resulted in commercial production of fiber glass
in the U.S., as an asbestos substitute. (Asbestos is a
naturally-occurring fibrous material that can be woven into
cloth, does not burn readily, has excellent properties for
thermal insulation, and therefore came into commercial use during
this century. [2, pgs.390-392] Fiber glass has many of the same
characteristics as asbestos.)
In 1938, the Owens Corning Fiberglas Company was formed, and
three years later, in 1941, evidence of pulmonary [lung] disease
was reported by Walter J. Siebert, who investigated the health of
workers in cooperation with Owens Corning. [1, pg.292] That same
year another investigator reported finding “no hazard to the
lungs” of workers exposed to glass fibers in the air. Scientific
disagreement of this sort has characterized the study of fiber
glass ever since; meanwhile fiber glass production has increased
steadily.
That same year (1941), the U.S. Patent Office issued patents for
353 glass wool products. Glass wool, fiber glass, fiberglas,
fibrous glass, and glass fibers are all names for the same thing:
thin, needle-shaped rods of glass, which nature does not make but
humans do.
Fiber glass 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 fiber glass.
As asbestos has been phased out because of health concerns, fiber
glass production in the U.S. has been rising. In 1975, U.S.
production of fiber glass was 247.88 million kilograms (545.3
million pounds); by 1984 it had risen to 632.88 million kilograms
(1392.3 million pounds). [1, pg.302] If that rate of growth
(10.4% per year) held steady, then production of fiber glass in
the U.S. in 1995 would be 4365 million pounds.
Fiber glass is now causing serious health concerns among U.S.
officials and health researchers. As we reported in RHWN #74, in
a series of papers published from 1969 to 1977, Dr. Mearl F.
Stanton of the National Cancer Institute found that glass fibers
less then 3 micrometers in diameter and greater than 20
micrometers in length are “potent carcinogens” in rats; and, he
said in 1974, “it is unlikely that different mechanisms are
operative in man.” A micrometer is a millionth of a meter (and a
meter is about three feet). Since that time, studies have
continued to appear, showing that fibers 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 fibers 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 it is caused
by asbestos fibers. Stanton continued his research and showed
that when glass fibers are manufactured as small as asbestos
fibers, glass causes cancer in laboratory animals just as
asbestos does. [4] Asbestos is a potent human carcinogen, which
will have killed an estimated 300,000 American workers by the end
of this century. [5] The finding that fiber glass causes diseases
similar to asbestos was chilling news in the early 1970s, and an
additional 25 years of research has not made the problem seem
less serious. Workers in fiber glass manufacturing plants are
exposed to concentrations of fibers far lower than the
concentrations to which asbestos workers were exposed, yet
several industry-sponsored epidemiological studies of fiber glass
workers in the U.S., Canada, and Europe have reported
statistically significant increases in lung cancer. [6]
The International Agency for Research on Cancer (IARC), of the
World Health Organization, listed fiber glass as a “probable
[human] carcinogen” in 1987. In 1990, the members of the U.S.
National Toxicology Program (NTP) –representatives of 10 federal
health agencies –concluded unanimously that fiber glass “may
reasonably be anticipated to be a carcinogen” in humans. [3] NTP
members 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, which is mandated by Public
Law 95-622. But industry intervened politically.
Four major manufacturers of fiber glass insulation campaigned for
three years to prevent their product from being labeled a
carcinogen by NTP (see RHWN #367). 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 (HHS), Donna E. Shalala, signed the
REPORT and sent it to Congress, thus making it official policy of
the U.S. government that fiber glass is “reasonably anticipated
to be a carcinogen.” In the U.S., fiber glass must now be
labeled a carcinogen.
Announcing this decision, government officials tried to play down
its significance. Bill Grigg, a spokesperson for the U.S. 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.” [7] To make such a statement, Mr. Grigg had
to ignore at least six epidemiological studies showing
statistically-significant increases in lung cancer among
production workers in fiber glass factories. [6] Indeed, according
to researchers in the Occupational Safety and Health
Administration (OSHA, another division of Health and Human
Services) fiber for fiber, fiber glass is a more potent
carcinogen than asbestos. [8, pg.580]
Fiber glass –a material that nature does not make –is now
measurable everywhere in the air. The air in cities, rural
areas, [1, pgs.311-314] and remote mountain tops [4] now contains
measurable concentrations of fiber glass. If the dose-response
curve is a straight line (that is to say, if half as much fiber
glass causes half as much cancer) and if there is no threshold
dose (no dose below which the cancer hazard disappears), then
exposing the Earth’s 5.7 billion human inhabitants to low
concentrations of fiber glass will inevitably take its toll by
causing excess cancers in some portion of the population.
According to OSHA researchers, an 8-hour exposure to 0.043 glass
fibers per cubic centimeter of air is sufficient to cause lung
cancer in one-in-every-thousand exposed workers during a 45-year
working lifetime. [8, pg.580] In rural areas, the concentration
of fiber glass in outdoor air is reported to be 0.00004 fibers
per cubic centimeter, about 1000 times below the amount thought
to endanger one-in-every-thousand fiber glass workers. [1, pg.314]
But people in rural areas breathe the air 24 hours a day, not 8
hours. Furthermore, a human lifetime is 70 years, not the 45
years assumed for a “work lifetime.” Moreover, one-in-a-thousand
is not adequate protection for the general public; U.S.
Environmental Protection Agency uses one-in-100,000 or
one-in-a-million as a standard for public exposures. (And,
finally, in urban air, there’s 10 to 40 times as much fiber glass
as in rural air.) Therefore, the amount of fiber glass in the
outdoor air in the U.S. and Europe (and presumably elsewhere)
already seems higher than prudent public health policies would
permit. Assuming a straight-line dose-response curve and no
threshold, we believe there is ample reason to be concerned about
the human health hazards posed by fiber glass in the general
environment. (And this says nothing about the hazards to
wildlife.)
It has been 25 years since researchers at the National Cancer
Institute concluded that fiber glass is a potent carcinogen in
experimental animals. During that time, additional research has
confirmed those findings again and again. [8] During the same
period, the amount of fiber glass manufactured has increased
rapidly year after year. Ninety percent of American homes now
contain fiber glass insulation. All of this fiber glass will
eventually be released into the environment unless special (and
very expensive) precautions are taken to prevent its release. We
believe the likelihood of Americans taking such precautions is
nil. Billions of pounds of fiber glass now in buildings will
eventually be dumped into landfills, from which it will leak out
slowly as time passes. Elevated concentrations of fiber glass
are already measurable in the air above landfills today. [4]
In 1991, PATTY’S INDUSTRIAL HYGIENE AND TOXICOLOGY, a standard
reference book on work-place safety and health, said about fiber
glass, “…it is prudent for industrial hygienists to treat these
materials with the same precautions as asbestos.” [1, pg. 324]
How do we treat asbestos? In the U.S., all new uses of asbestos
have been banned. A ban of fiber glass is long overdue.
                
                
                
                
    
–Peter Montague
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[1] Jaswant Singh and Michael A. Coffman, “Man-Made Mineral
Fibers,” in George D. Clayton and Florence E. Clayton, editors,
PATTY’S INDUSTRIAL HYGIENE AND TOXICOLOGY FOURTH EDITION, VOLUME
1, PART B (New York: John Wiley & Sons, 1991), pgs. 289-327.
Special thanks to the advocacy organization, Victims of
Fiberglass (VOF), for keeping us informed about these issues
over the years. VOF publishes an excellent newsletter,
FIBERGLASS ROOTS OF CANCER; contact Bob Horowitz, Victims of
Fiberglass, P.O. Box 894, Bryte, CA 95605-0894; phone (916)
371-0656.
Descriptor terms: fiber glass; fiberglass; fiberglas; fibrous
glass; glass wool; mmmf; man-made mineral fibers; carconigens;
cancer; lung cancer; studies; epidemiology; energy conservation;
insulation; asbestos; iarc; international agency for research on
cancer; who; world health organization; national toxicology
program; ntp; victims of fiberglass; health and human services;
occupational safety and health administration; hhs; osha;