Pesticide Testing on Humans Is Ethical, Science
By Shankar Vedantam
Washington Post Staff Writer
Friday, February 20, 2004; Page A03
It is ethical to test pesticides and pollutants on human volunteers in
order to determine whether environmental safety standards can be
lowered, a top panel of scientists said yesterday in an opinion that is
expected to strongly influence government policy.
Many scientists and ethicists have argued that such research is never
justified, and yesterday's unprecedented verdict by the National Academy
of Sciences took environmentalists by surprise.
The pesticide industry has vehemently supported such tests for years,
arguing that current regulatory limits on exposure to environmental
toxins are overly cautious. Manufacturers of pesticides and companies
that produce pollutants say human studies will demonstrate that higher
levels of toxins in the air and water are not harmful.
While volunteers would derive no benefit and some might incur transient
harm, the panel of experts said this would be outweighed by societal
benefits. Besides helping regulators set accurate benchmarks for
environmental dangers, such trials might also address, for example, how
much insecticide can safely be used to fight a malaria outbreak.
Yesterday's decision by a panel of the National Research Council will
allow the Environmental Protection Agency to devise a final rule over
the next several months, an EPA spokesman said. Both the pesticide
industry and environmental groups said they expect the agency will
accept the recommendation of the panel, which would also allow the EPA
to evaluate human studies of pesticides that had previously been
conducted, and give the industry an incentive to conduct new trials.
The panelists called for a rigorous safety and ethics system to evaluate
and approve such trials, much like the system used by the Food and Drug
Administration to evaluate drug trials conducted by the pharmaceutical
While there was no "foolproof mechanism" to eliminate all risk of
patient harm, the joint chairman of the panel, James Childress, an
ethics professor at the University of Virginia, said that the risk for
volunteers would generally be "exceedingly low."
Environmental groups acknowledged that the panel had tried to institute
safeguards, but feared that trials would still cause harm.
Currently, to determine what level of a toxin is safe for human
exposure, regulators at the EPA first determine what dose is toxic to
animals. Regulators divide that dose by 10, because humans may react
more sensitively than animals -- called the "inter-species safety
factor." Because some people are more sensitive than others, regulators
lower the potentially toxic dose by another factor of 10. Finally, to
protect children and fetuses, a third safety factor of as much as 10 is
introduced. Collectively, these safety factors can reduce human exposure
limits to toxins to one-thousandth the dose that harms animals.
The goal of human pesticide studies is to lower the inter-species
factor. If companies can show that humans are not more sensitive than
rats, higher exposure levels might be permitted.
Richard Wiles, senior vice president at the Environmental Working Group,
an advocacy organization, said that while the EPA can enforce a tenfold
safety factor to protect children, it does not do so for many chemicals.
As a result, he said, the exposure limit for humans might end up being
only one-tenth the toxic animal dose.
"Pesticide law would have gone from the toughest law on the books to the
weakest law on the books through this marvelous sleight of hand that the
industry has pulled," Wiles said.
The report allowed for the possibility of trials involving children, but
panelists said they could not imagine such tests would ever be
conducted. But Erik Olson, senior attorney at the Natural Resources
Defense Council, an environmental group, said such tests have already
been performed: As recently as 2000, he said, a manufacturer petitioned
the EPA to consider data from an Italian study of infants that
deliberately exposed them to dichlorvos, an insecticide sold under the
brand name Vapona.
Dichlorvos manufacturer Amvac Chemical Corp., of Newport Beach, Calif.,
petitioned the agency to consider two 1969 trials titled "Exposure of
Newborn Babies to Vapona Insecticide" and "Clinical Effects of Exposure
to DDVP (Vapona) Insecticide in Hospital Wards."
Pesticide Testing on Humans Is Ethical, Science Panel Says
A call to Amvac was returned by consultant Howard Berman, president of
Environmental Mediation Inc. Berman said that the trials cited in the
petition had not been commissioned by Amvac. Speaking on behalf of the
company, he said Amvac had no plans to conduct trials among children.
Jay Vroom, president of Croplife America, which represents pesticide
manufacturers, said he knew of no company that planned to test
pesticides on children.
But data from adult trials would be useless in predicting the risk for
children, said Philip Landrigan, a Mount Sinai pediatrician in New York
and chairman of a National Academy of Sciences panel in 1993 that
examined the risk of pesticides on children.
During the Clinton administration, the EPA refused to consider any human
trials. The Bush administration reopened the possibility of using the
The pesticide industry dismissed critics of the trials as biased, and
environmental groups countered yesterday with similar criticism of the
NRC panel. Olson, the NRDC attorney, produced documentation that panel
member James Bruckner, a professor of pharmacology and toxicology at the
University of Georgia, was a paid expert witness for Lockheed Martin
Corp., which is fighting a lawsuit in California over whether pollution
from its products might have caused cancer and thyroid problems.
Gail Rymer, a spokeswoman for Lockheed Martin in Bethesda, confirmed
that the company had paid for a human study of a rocket fuel component
called perchlorate in hopes of influencing the California lawsuit.