WASHINGTON (Reuters Health) - Scientists and environmental groups
urged a federal advisory panel Wednesday to recommend a ban on chemical
industry experiments that test the safety of pesticides and other
potentially toxic chemicals in humans.
Labeling the experiments unethical and scientifically suspect, the
groups asked experts on a National Academy of Sciences panel to condemn
the studies and recommend that government regulators refuse to consider
them when evaluating the safety of companies' chemical agents or pollutants.
But representatives of the pesticide industry defended the experiments,
saying that they are ethically sound and essential to accurately determining
safe exposure levels for members of the public.
Manufacturers of pesticides or other chemicals sometimes give adult
volunteers a dose of the product in order to determine what levels
humans can tolerate without getting sick. Determining a safe level
for humans is necessary before companies can gain Environmental Protection
Agency (EPA) approval to market most pesticides and other chemicals.
Scientists attacked the studies Wednesday, calling them unethical
because people can only be hurt, and not helped, by receiving doses
of toxic chemicals.
Most ethical standards for human medical research, including the
Nuremburg Code created after the trials of Nazi doctors conducting
research on World War II Holocaust prisoners, require that study participants
stand a chance of gaining from research conducted on them.
"There is no benefit to the health of a subject nor to the health
of anyone else," said Dr. Lynn Goldman, a professor of environmental
health sciences at Johns Hopkins University and chair of the Children's
Environmental Health Network.
Goldman conducted a study of a 1985 case in which up to 1,373 people
were sickened after eating watermelon contaminated with the pesticide
Aldicarb. Researchers uncovered probable illnesses in persons exposed
to Aldicarb levels 10 times lower than those deemed safe in a 1971
study in which manufacturer Union Carbide gave it to 12 men.
The NAS panel is scheduled to meet over the next year to eventually
advise the EPA on the propriety and scientific validity of human chemical
tests. Citing ethical concerns, EPA in 2001 imposed a moratorium on
accepting data from human chemical tests, a move that sparked a lawsuit
by the pesticide industry.
Companies frequently test the effects of their chemicals in animals
before applying for government marketing approval. When a chemical
has not been tested in humans, the laws often require EPA to assume
that a safe level for humans is many times--sometimes 100 times--lower
than the level that causes sickness in animals.
Industry scientists told the panel that human chemical testing is
always done with the informed consent of subjects and that the trials
are key to determining exactly how humans react when exposed to dangerous
"The knowledge we gain from human volunteer studies is absolutely
critical," said Dr. Monty Eberhart, director of product safety
management for Bayer CropScience. The company is a major pesticide
producer and one of the companies suing the EPA to lift the moratorium
on human-derived data.
Eberhart told the panel that animal studies have often failed to
accurately predict safe pesticide levels for humans.
"Only human data directly reflects human response," said
Judith A. MacGregor, a researcher with Toxicology Consulting Services,
a private research company.
But Goldman, of Johns Hopkins University, cited her study as proof
that small trials testing chemicals in adult men tell little about
how the compounds will effect people of different ages or sexes. One
of the people hospitalized after eating the contaminated watermelon
was a 66-year-old woman.
Others accused the industry of trying to use the self-financed experiments
to weaken environmental standards governing its chemicals. Though
many of the trials are conducted in only a few people, they could
still be used to permit easier marketing if they showed that humans
could tolerate a higher chemical dose than animals can.
"These tests are performed for the purposes of weakening regulatory
standards," said Jennifer Sass, a senior scientist at the Natural
Resources Defense Council.
Peg Cherny, vice president for government relations at Bayer CropScience,
denied that the company's position or its lawsuit to force EPA to
accept human studies is an attempt to weaken safety standards.
"We're trying to get appropriate standards," she said in
Lawyers for the EPA and pesticide industry are set to argue the case
before the Federal Appeals Court in Washington in March.
The NAS panel is due to release its recommendations on human-based
chemical testing in about one year, officials said.
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