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Risk/Benefit Balancing Under FIFRA (8/91)

Risk/Benefit Balancing Under FIFRA (8/91)

Pesticides are biologically active chemicals that kill or modify the behavior of problem insects, animals, microorganisms, weeds, and other pests. With pesticides, farmers can grow more and greater varieties of food more cheaply; home owners can control pests in their lawns, gardens and homes; and public health officials can control pests potentially harmful to our health. But there are disadvantages as well as benefits from using pesticides. By law, EPA must weigh the risks of pesticides to human health and the environment against their benefits with a multi-step process called risk/benefit balancing.


There are four steps in EPA's risk assessment process: hazard identification, dose/response assessment, exposure assessment, and risk characterization.

Hazard Identification.

EPA evaluates a pesticide's inherent toxicity - i.e., the types and degrees of harmful effects a pesticide may cause. This is done principally by evaluating laboratory studies conducted on animals. For example, laboratory studies attempt to determine if a chemical is an eye irritant, causes acute poisoning, causes birth defects, or causes cancer, among other effects.

Dose/Response Assessment.

A pesticide's potential for causing adverse health effects is identified through a battery of short-term or "acute" and long-term or "chronic" toxicity testing. In several series of tests, laboratory animals are exposed to different doses of a pesticide, and EPA scientists evaluate the tests to find the level of exposure in each of those studies that did not cause any non-cancer effect. This level is called the "No-Observed-Effect Level," or NOEL. The most appropriate NOEL is divided by an uncertainty factor, usually 100 or more, to determine what is called the Reference Dose (RfD) (once known as the Acceptable Daily Intake, ADI). At or below this level, it is assumed that daily exposure over a lifetime will not pose significant risks to health. In addition, EPA routinely requires multi-year laboratory animal feeding studies to screen pesticides for cancer effects. The Agency uses a "negligible risk" standard to address the risk of cancer from exposure to a pesticide through the food supply. EPA defines a negligible risk to mean that the estimated cancer risk can be no greater than a risk of one in one million or less (meaning that, at most, an individual would have a one in one million chance of developing cancer if exposed over a lifetime).

Exposure Assessment.

Once harmful health effects are identified in he laboratory tests, EPA must estimate the level, duration, frequency, and route of exposure for people. For example: Are people who regularly mix and apply pesticides exposed? Is there a chance of exposure to people through food and drinking water? Can plants and animals other than the targeted pests be harmed or killed by the pesticide?

Risk Characterization.

Finally, the risk from exposure to pesticides is estimated by integrating the above factors. By combining estimates of likely or actual pesticide exposure with the toxicity of the pesticide, EPA can characterize the risks that it poses. This usually involves extrapolating exposure in animals to humans because little direct information about the effects on humans is available. EPA relies on animal studies, assuming that the human response is qualitatively similar to that of animals and that humans will be at least as sensitive, and frequently, more sensitive to the effects of the pesticide.


EPA conducts a benefit assessment when deciding on whether to cancel a pesticide, and evaluates benefits when approving the use of a new pesticide under a conditional registration. The purpose of a benefit assessment is to determine the effectiveness and economic value of a pesticide compared to alternative chemical and nonchemical controls. A benefit assessment is specific for each registered use site (e.g., corn, soybeans, tomatoes, etc.). A benefit assessment is essentially an analysis of likely economic consequences resulting from the restriction or cancellation of a pesticide, and includes:

Biological Analysis.

The purpose of this analysis is to identify the importance of the pesticide in controlling the intended pest. As part of this process, EPA collects information on the nature and extent of the pest problem, the effectiveness of the pesticide and other chemical and non-chemical controls, and the biological impacts of controlling the pest. For agricultural pesticides, the analysis would compare the effects on crop yield or quality for the pesticide and its alternatives; the information is used to determine the pesticide's value in the production of the crop.

Economic Analysis.

An economic analysis translates the biological impact of yield loss, reduced crop quality, and alternative pest control methods into economic terms. EPA evaluates the economic impacts that are expected to occur for all of the affected sectors of the economy. For agricultural pesticides, economic effects include the costs and ability of farmers to produce the crops and, where appropriate, the subsequent costs to consumers who purchase those foods. In addition, secondary effects such as local employment are evaluated when appropriate. A low cost pesticide that produced substantial benefits to farmers, resulted in lower food costs to consumers, and had few alternatives, would be rated as having high benefits. On the other hand, if there were several alternatives to a pesticide that were comparably priced and equally effective, the pesticide would have relatively low benefits.

--U.S .EPA, For Your Information, 8/91