Testing Pesticides on Humans Approved by Federal Panel

WASHINGTON, DC, February 23, 2004 (ENS) - "Intentional dosing of humans with toxic chemicals," including tests on children, might once again be permitted in the United States based on the report of a National Research Council panel issued Friday. While the panel says such experiments must meet "the most stringent scientific and ethical standards," their report suggests lifting of the moratorium on human testing that is now in place could be useful in safety evaluations.

The report roused outrage and dismay from physicians and environmental organizations, who said there are no conditions under which deliberate dosing of humans with pesticides should be permitted.

The decision "opens a Pandora's Box" to human testing of highly toxic substances, said Physicians for Social Responsibility President Michael McCally, M.D., Ph.D. "Human testing of industrial chemicals for toxicity is per se unethical," he said.

"Over the last 50 years," the committee's report states, "tens of thousands of chemicals have been developed and introduced into the environment of the United States. In a typical year, more than six billion pounds of toxic chemicals are released by industrial facilities into the environment. Another 1.3 billion pounds of pesticides are applied annually to agricultural fields, homes, gardens, schools and other settings."

It is "critically important" to understand the hazards of chemicals and control human exposure to them, the panel said.

An Air Tractor 402B aircraft sprays an insecticide mixture on a test field. (Photo by Scott Bauer courtesy USDA)

But the EPA requested an analysis from the National Research Council on the circumstances under which the agency should accept and consider intentional human dosing studies conducted by companies and other third parties to gather evidence relating to the risk of a chemical and the conditions under which exposure to it could be considered safe.

"Human studies involving pesticides, air pollutants, or other toxicants – as opposed to therapeutic agents – are particularly controversial, and because of this, EPA should subject these studies to the highest level of scientific and ethical scrutiny," said committee co-chair James Childress, a professor of ethics and medical education, and director of the Institute for Practical Ethics and Public Life in the Department of Religious Studies at the University of Virginia, Charlottesville.

"Our report proposes a framework for EPA's oversight of this research. And the recommended framework should apply to studies that are sponsored by so-called third parties – private companies or other sources outside the agency – as well as by EPA," Childress said.

But McCally said, "Some of these chemicals are poisons derived from chemical warfare nerve agents. We don't permit human research on radiation exposure to determine how it causes disease. The same should go for human research on toxic chemicals."

Entomologist Brad Higbee examines a Golden Delicious apple for codling moth damage. (Photo By Scott Bauer courtesy USDA)

"We urge the EPA to continue the current moratorium on these studies," Wiles said. "If the EPA begins to accept human experiments we expect to see companies taking advantage of any and all ambiguities in the guidelines and to continue performing unethical tests that will help keep unsafe chemicals in our food and water."

The EPA request for an analysis stems from 1996 when Congress passed the Food Quality and Protection Act, which tightened safety standards on pesticides. Some chemical manufacturers said that the new standards and "reference doses" were not based on a solid scientific foundation. To back this assertion, several companies sponsored or conducted clinical trials to assess human risk from exposure to pesticides and submitted the results to the agency for consideration.

Some public health advocates and others, questioning the industry's research findings, urged the agency to reject the results.

In response to the controversy, EPA announced in 1998 that it would not use the studies to inform its policymaking until many ethical and scientific issues had been resolved.

Later, a majority of a joint subcommittee of EPA's Science Advisory Board and the Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel concluded that human dosing studies could be ethically and scientifically justified under certain circumstances, subject to stringent conditions and oversight. The National Research Council (NRC) panel agreed.

The NRC committee recommended that intentional dosing studies in humans be conducted and used for EPA regulatory purposes only if all of the following conditions are met:

Pesticide is sprayed on pecan trees. This new nozzleless sprayer uses one-half to two-thirds less spray to kill insects. (Photo by Rob Flynn courtesy USDA)

• Studies must be necessary and scientifically valid, addressing important regulatory questions that cannot be answered with animal studies or other studies that do not involve human testing. They must be designed, conducted, and reported in a scientifically rigorous manner to ensure that they answer a specific research question.

• The possible benefits to society from such studies must outweigh any anticipated risks to participants.

• Studies whose results would be used for the sole purpose of improving the scientific accuracy of EPA's established reference doses for humans, and that would not provide health benefits otherwise, would be justified only if there were no identifiable risks to participants, or if investigators could show with reasonable certainty that participants would not be harmed.

• All of the recognized ethical standards and procedures for protecting the interests of study participants must be observed, including equitable selection and recruitment of human subjects, the obtaining of informed consent, and independent review of the scientific and ethical merits of a given study by an institutional review board or its equivalent.

The NRC panel recommended that the EPA establish a Human Studies Review Board to evaluate all human dosing studies – both at the beginning and upon completion of the experiments – if they are carried out with the intent of affecting the agency's policymaking.

"The committee purposely set a very high bar when it comes to intentional human dosing studies, especially for those that do not promise health or environmental benefits," said committee co-chair Michael Taylor, senior fellow and director of the risk, resource, and environmental management division of Resources for the Future, an economics research group based in Washington, DC.

"Improving the quality of the science used for regulatory purposes is itself a worthy social goal," said Taylor, "but it could never justify harming human research participants."

Read the report, "Intentional Human Dosing Studies for EPA Regulatory Purposes: Scientific and Ethical Issues" online at: http://books.nap.edu/books/0309091721/html/index.asp