People calling themselves "conservatives" in Congress are preparing to
flay U.S. Environmental Protection Agency (EPA) scientists for their
reassessment of dioxin --the agency's 4-year effort to determine the
true hazards of dioxin. Dioxin is a highly toxic byproduct produced in
the manufacture of many pesticides, and by the routine operation of all
incinerators, metal smelters, and chlorine-using paper mills. In 1986,
EPA concluded that dioxin was one of the two or three most powerful
poisons ever studied, and accordingly, set strict limits on certain
releases into water. As the agency moved to enforce those limits in the
late 1980s, industrial dioxin-producers developed a strategy for
reversing EPA's stance: They would force the agency to undertake a
scientific reassessment of dioxin, a reassessment they evidently
thought they could control.
The paper industry took the lead in pressuring EPA to formally reassess
dioxin. (See REHW #269, #270 and #275.) On January 23, 1991, four chief
executive officers of paper companies visited William Reilly, who was
then the head of EPA. The four executives memorialized their meeting by
sending Reilly a letter dated January 25th --a letter that (thanks to
Greenpeace) found its way into the record of a public hearing on the
dioxin reassessment which EPA held in Washington, D.C. November 15,
1991. In their letter, the four executives (John A. Georges,
International Paper; T. Marshall Hahn, Jr., Georgia-Pacific Corp.;
Furman C. Moseley, Simpson Paper; and Andrew C. Sigler, Champion
International) thanked Reilly for his receptiveness to their ideas
during the meeting January 23: "We were also encouraged by what we
perceived as your willingness to move expeditiously to re-examine the
potency of dioxin and chloroform in light of the important new
information that has been submitted with respect to those chemicals,"
the paper company executives said. They rebuked EPA for "failure to act
on the emerging health science." They told Reilly there is now a
"prevailing view that low-level dioxin exposures do not pose a serious
health threat." "Despite this new reality," they said, "EPA has taken
no tangible or timely steps to revisit its health criteria for dioxin,
and has even failed to temper the Agency's zeal in acting on the worst
As a direct result, EPA's "scientific reassessment" of dioxin was born.
By April, 1991, Reilly had geared up his agency for a major effort to
reassess the toxicity of dioxin, just as the paper industry had
requested. In August, just 4 months into the multi-year study, Reilly
told the NEW YORK TIMES how he expected the dioxin reassessment to turn
out: "I don't want to prejudge the issue, but we are seeing new
information on dioxin that suggests a lower risk assessment for dioxin
should be applied," Reilly told the TIMES (August 15, 1991, pg. 1).
However, the scientific reassessment did not turn out as Reilly and the
paper industry supposed it would. EPA scientists evidently took their
mandate seriously. They designed a reassessment process that involved
original laboratory research, many meetings with non-government
scientists, at least 2 public hearings, and many drafts of the 9-volume
reassessment document, which was peer-reviewed prior to release. Eight
of the nine volumes were written by non-governmental scientists. EPA
had never before involved such a large number of non-agency scientists
in its work. It managed to solicit and include the viewpoints of
industry, academia, government, and the general public.
As a result, EPA scientists concluded a year ago that dioxin probably
causes cancer in wildlife and humans, and that it harms the immune
system and the reproductive systems in fish, birds, and mammals
(including humans) at doses that are miniscule. The lead scientist on
the EPA reassessment team, Dr. Linda Birnbaum,
said she and her colleagues now consider dioxin an "environmental
hormone" capable of disrupting a large number of bodily processes in
fish, birds, and mammals, including humans. Dioxin, EPA said, is
especially powerful in its effects on the unborn and the newly-born.
(See REHW #290, #390, #391, and #414.) This was hardly the outcome the
paper industry had expected.
The final draft of the 9-volume reassessment document went to EPA's
science advisory board (SAB) this year; at an SAB meeting May 16, 1995,
parts of the dioxin reassessment were criticized. Specifically, the SAB
asked EPA to provide better support for some of the conclusions in
Volume 9 (conclusions which we summarized in REHW #390 and #391), but
they did not tell EPA to do any additional scientific work.
Using the SAB's comments on the reassessment (which have not yet been
made public) as a political springboard, a group of so-called
"conservatives" of both parties in Congress are planning to investigate
"whether sound science is being distorted for preconceived policy ends,
and the potential economic impact of future mandates based on this
Congress has scheduled a public hearing Sept. 13 before the House
Subcommittee on Energy and the Environment of the Committee on Science.
It is widely understood in Washington that this hearing is going to be
a "witch hunt" aimed at punishing EPA for reaching conclusions that the
paper industry and other industrial poisoners don't like.
Everyone who has followed the story of tobacco during the last 20 years
knows there are a handful of scientists who still claim there is no
compelling evidence that tobacco causes lung cancer in humans. These
"tobacco scientists" have counterparts in the dioxin world, and this
little group of dioxin denial specialists will be showcased at the
hearing September 13. They are expected to say that EPA and its 100-or-
so independent outside scientific advisers have made a mountain out of
a mole hill. Congress may use their testimony as an excuse to further
slash EPA's research budget, thus exorcising the source of much recent
bad news about dioxin.
Meanwhile, the scientific evidence linking dioxin to serious
reproductive disorders in mammals has continued to accumulate. Just
this month, Dr. Earl Gray (a respected EPA researcher) published the
third in a series of studies of the effects of a single low dose of
dioxin on rats and hamsters. This series began with 3 studies published
in 1992 by Dr. Richard E. Peterson at the University of Wisconsin.
In the Peterson studies, young male rats whose mothers were given as
little as 0.064 micrograms of dioxin per kilogram of body weight showed
consistently reduced levels of male hormones, plus a variety of sex-
related changes, including:
** smaller accessory sex organs, including smaller testicles;
** slower sexual maturation;
** distinctly feminine-style regulation of one hormone related to
** greater willingness to assume a receptive-female posture when
approached by a sexually stimulated male.
Other effects revealed by the Wisconsin studies included:
** Even the lowest dose tested (0.064 micrograms of dioxin per kilogram
of the mother's body weight), yielded consistent reductions in a male
offspring's daily sperm production.
** The developing male reproductive system is more sensitive to the
effects of this hormone-like toxicant [dioxin] that any other organ or
** The unborn or newborn is about 100 times more sensitive to dioxin
than the sexually mature animal.
What do these studies mean for humans?
The Wisconsin researchers speculated, "Thus the findings from this
study raise the possibility that TCDD could potentially affect sexually
dimorphic behavior in man if exposure were to occur during fetal
development." "Sexually dimorphic behavior" refers to the bodily and
behavioral differences between men and women. Is it possible that
homosexual behavior in some individuals may be conditioned by exposure
to chemicals before birth? It seems to be so in laboratory animals, in
wildlife, and in some humans whose pregnant mothers were exposed to
diethylstilbestrol (DES), a powerful hormone.
Commenting in 1992 on the Peterson rat studies (which she called
"highly significant"), Linda Birnbaum of EPA said, "The real question
is how general these effects are." And if these effects occur in
another species? "I would get very concerned [about the potential
human-health implications]," Birnbaum told Janet Raloff, a reporter for
In March, 1995, Birnbaum herself (with Earl Gray, William Kelce and
others) published studies confirming that many of Peterson's findings
could be reproduced in another strain of rat, and in another species
entirely, the Syrian hamster. The hamster is known for being
insensitive to dioxin's effects, yet single low- dose exposures of
pregnant hamsters to dioxin produced nearly a 60% reduction in sperm
count in male offspring, plus other important changes, such as a 23%
reduction in the size of the adrenal gland.
This month, Earl Gray published a third study showing that a single low
dose of dioxin to pregnant rats could produce hermaphroditic FEMALE
offspring. Hermaphroditic means having male and female sex organs
simultaneously. Other effects included 30% reduction in the weight
of the ovaries; shortened reproductive life span; and increased
incidence of cystic hyperplasia of the endometrium (formation of
multiple cysts in the tissues lining the uterus).
There can no longer be any doubt that dioxin in very low exposures
during early development in mammals can dramatically alter sexual
development and behavior. The public health implications are enormous.
This Congress seems in a mood to crucify EPA scientists for reaching
politically incorrect conclusions about dioxin. In an earlier time
(1632), a scientist like Galileo, threatened by powerful religious
zealots of his day, saved himself by recanting. Will EPA scientists be
forced to do the same?
 Letter dated August 10, 1995, from Dana Rohrabacher to EPA chief
Carol Browner inviting her to testify September 13, 1995 before the
House Energy and Environment Subcommittee of the Committee on Science.
 Thomas A. Mably and others, "IN UTERO and Lactational Exposure of
Male Rats to 2,3,7,8-Tetrachlorodibenzo-p-dioxin. 1. Effects on
Androgenic Status." TOXICOLOGY AND APPLIED PHARMACOLOGY Vol. 114 (May,
1992), pgs. 97-107. And: Thomas A. Mably and others, "IN UTERO and
Lactational Exposure of Male Rats to 2,3,7,8-Tetrachlorodibenzo-p-
dioxin. 2. Effects on Sexual Behavior and the Regulation of Luteinizing
Hormone Secretion in Adulthood." TOXICOLOGY AND APPLIED PHARMACOLOGY
Vol. 114 (May, 1992), pgs. 108-117. And: Thomas A. Mably and others,
"IN UTERO and Lactational Exposure of Male Rats to 2,3,7,8-
Tetrachlorodibenzo-p-dioxin. 3. Effects on Spermatogenesis and
Reproductive Capability." TOXICOLOGY AND APPLIED PHARMACOLOGY Vol. 114
(May, 1992), pgs. 118-126.
 Relevant studies are reviewed in Glen A. Fox, "Epidemiological and
Pathobiological Evidence of Contaminant-Induced Alterations in Sexual
Development in Free-Living Wildlife," in Theo Colborn and Coralie
Clement, editors, CHEMICALLY-INDUCED ALTERATIONS IN SEXUAL AND
FUNCTIONAL DEVELOPMENT: THE WILDLIFE/HUMAN CONNECTION [Advances in
Modern Environmental Toxicology Vol. XXI] ( Princeton, N.J.: Princeton
Scientific Publishing Co., 1992), pgs. 147-158. The human evidence from
DES exposures is described in the same volume by Melissa Hines,
"Surrounded by Estrogens? Considerations for Neurobehavioral
Development in Human Beings," pgs. 261-281.
 J. Raloff, "Perinatal dioxin feminizes male rats," SCIENCE NEWS
Vol. 141 (May 30, 1992), pg. 359.
 L.E. Gray, Jr., and others, "Exposure to TCDD during Development
Permanently Alters Reproductive Function in Male Long Evans Rats and
Hamsters: Reduced Ejaculated and Epididymal Sperm Numbers and Sex
Accessory Gland Weights in Offspring with Normal Androgenic Status,"
TOXICOLOGY AND APPLIED PHARMACOLOGY Vol. 131 (1995), pgs. 108-118.
 Leon Earl Gray, Jr., and Joseph S. Ostby, "IN UTERO 2,3,7,8-
Tetrachlorodibenzo-P-dioxin (TCDD) Alters Reproductive Morphology and
Function in Female Rat Offspring," TOXICOLOGY AND APPLIED PHARMACOLOGY
Vol. 133 (1995), pgs. 285-294.
Descriptor terms: dioxin; toxicity; endocrine system; endocrine
disrupters; congress; public hearings; conservatives; conservatism;
hermaphroditism; homosexuality; sperm count; growth; rats; hamsters;
humans; morbidity; epa; linda birnbaum; earl gray; studies; janet
raloff; dioxin reassessment; pulp and paper industry; corruption;
science; epa science advisory board; environmental hormones; fish;
birds; wildlife; mammals; adrenal gland; testicles; feminization;
masculinization; tobacco; william kelce; endometrium; galileo;