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Debra Edwards, Ph.D.

May 2008
Debra Edwards, Ph.D., director of the EPA's Office of Pesticide Programs, responds to Jay Feldman's comments.

EPA's pesticide program is based on rigorous, often cutting-edge science. In carrying out our mandates under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) as amended by the Food Quality Protection Act of 1996, EPA bases its decisions to register pesticides for use in the United States on scientific data showing that the pesticides meet applicable safety standards to protect human health and the environment when used as directed on product labeling.

We have established a new "registration review" program for all pesticides on the market. Changes in science, public policy, and pesticide use practices will occur over time. Through the new registration review program, the Agency will periodically and routinely reevaluate pesticides to make sure that as change occurs, products in the marketplace still meet the statutory safety standard. The registration review program challenges EPA to continuously improve its processes, science, and information management while maintaining a collaborative and open process for decision-making.

Rigorous risk assessment is the heart of our evaluation and reevaluation programs. In the risk assessment process, we consider all potential exposure scenarios -- food, drinking water, non-occupational (e.g., residential and recreational) exposures. This involves evaluation of a comprehensive suite of data, typically hundreds of individual studies, and includes assessment of break-down products in addition to the primary pesticide chemical.

EPA has also developed a framework for conducting cumulative risk assessments where EPA evaluates the potential for people to be exposed to more than one pesticide at a time from a group of pesticides with an identified common mechanism of toxicity. Cumulative assessments consider exposures from food, drinking water, and residential sources, as well as regional exposures from residential and drinking water sources since this is the most appropriate way to account for the considerable variation in potential exposures across the country. EPA's cumulative assessments, therefore, approximate as closely as possible people's actual exposures and potential risks resulting from current uses of these pesticides in different parts of the country.

In conducting risk assessments, we may encounter situations where risks are potentially high. In these situations, we will do additional analyses to better understand what factors are most important in the risk picture and thus what possible risk mitigations could be used to most effectively reduce the risk. The major goal is to consistently and properly characterize the risk to help the risk managers make their decisions. We also recognize that there are countless permutations of chemicals that people might encounter that could make them more sensitive to an exposure to a particular chemical, and that some individuals are naturally more sensitive than others. This is why we include uncertainty factors in our risk assessments.

Regarding the issue of the "potency" of the next generation of chemicals, we require all pesticides to be tested at multiple doses to try to determine a level at which no adverse effects are observed. We modify our tests when we become aware of new technology that is more sensitive. In fact, the Agency has a large research project using specialized genetic testing techniques (known as toxicogenomics) to try to increase the sensitivity of our screening ability.

Our main concern is to identify all the adverse effects that may result from exposure to a pesticide, regardless of the mechanism by which they are caused. The tests EPA has long required are designed to determine whether there are effects on organ systems, developmental and reproductive effects, which include sexual maturation, the development of cancer over the lifetime of the animal, neurobehavioral effects, etc. These studies measure the types of endpoints that would be expected to occur as a result of endocrine disruption. FQPA also required EPA to develop new methods to assess the ability of pesticides to interact with endocrine systems and thereby to cause adverse effects. While EPA already had test methods for assessing the range of adverse effects that could result from endocrine disruption, we have now developed and will begin requiring new studies to help us understand whether endocrine disruption is the mechanism causing the effects. EPA also carefully evaluates potential risks in recreational activities such as golfing. For example, we estimated the potential exposure and risks received not only by adults but also by both children aged 7-12 and teenagers in the chlorpyrifos risk assessment. The assessment of the use of chlorpyrifos on golf courses shows that this use met our rigorous safety standard.

One of the hallmarks of our program is the transparency and openness in which we operate. In fact, the public participation process we follow for pesticide risk assessment and risk management proposals is considered a model for open government. The six-stage process was actually developed through a very public collaboration of our many and diverse stakeholders who were members of a joint EPA-USDA Federal advisory committee -- the Tolerance Reassessment Advisory Committee.

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