Pesticides: Reducing Exposure to Residues of Canceled Pesticides
Released: 1994-12-28T00:00:00

Letter

Introduction

Pesticides are used extensively in agricultural production throughout the world to control or kill insects, fungi, or other pests and to increase crop yields. But pesticides can also harm human health and the environment. As the types and number of pesticides have grown over the past 30 years, their effects on health and the environment have come under closer scrutiny. And as scientific evaluation has shown that certain food-use pesticides can cause cancer, birth defects, and other disorders, the use of some of these pesticides has been banned, or canceled, in the United States.

But canceling a pesticide may not eliminate all of its risks, particularly if its residues persist in the environment or appear on imported foods. Hence, federal food safety agencies must decide not only which pesticides to cancel but also how to regulate the residues of canceled pesticides that continue to appear in foods. These decisions made after a pesticide has been canceled can have important health and economic implications.

Federal Agencies Share Responsibility for Ensuring Pesticide Safety

Federal responsibility for protecting public health and the environment from unsafe pesticides is shared by the Environmental Protection Agency (EPA), the Food and Drug Administration (FDA), and the U.S. Department of Agriculture (USDA). Broadly speaking, EPA sets standards for pesticide safety, which FDA and USDA monitor and enforce.

EPA Registers Pesticides and Sets Tolerances for Their Residues

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), EPA registers (licenses) pesticide products for use on specific crops grown in the United States. EPA may register a pesticide if it determines, among other things, that the pesticide will perform its intended function without causing “unreasonable adverse effects on the environment.” FIFRA defines this term to mean “any unreasonable risk to man or the environment, taking into account the economic, social, and environmental costs and benefits” of the pesticide’s use. EPA may register a single pesticide for multiple food and nonfood uses.

Residues of a pesticide used on a food or feed crop can remain on the food or feed and be ingested with it. EPA is required under the Federal Food, Drug, and Cosmetic Act (FFDCA) to establish a tolerance—or an exemption from a tolerance—for any registered use of a pesticide on food or animal feed. A tolerance specifies the maximum amount of the pesticide’s residue that may legally remain in or on the food or feed. A single pesticide registered for multiple food or feed uses must have multiple tolerances.

FDA and USDA Monitor Residues and Enforce Tolerances

FDA and USDA monitor pesticides’ residues in foods and feed sold in interstate commerce using the tolerances established by EPA. If food or feed products contain residues of pesticides that have not been granted tolerances (or exemptions from tolerances) or if residues exceed tolerances, foods are considered adulterated and are subject to seizure. FDA monitors most foods sold in interstate commerce except meat, poultry, and certain egg products, which are monitored by USDA. States are responsible for monitoring foods that are not sold in interstate commerce.

EPA Cancels Registrations for Unsafe Pesticides

After registering a pesticide, EPA continues to evaluate its safety, principally through two major programs—reregistration and special review. If EPA finds that a pesticide poses unreasonable risks to humans or the environment, the agency may cancel the registrations for some or all of its uses. A manufacturer may also voluntarily cancel a pesticide’s registrations.

Under amendments to FIFRA, enacted in 1972 and 1988, EPA is reevaluating and reregistering thousands of previously registered pesticide products on the basis of current scientific standards. In implementing this mandate, EPA is focusing primarily on about 600 active ingredients that are the main components of the individual pesticide products. Although, as we reported in May 1993, EPA will not complete its reregistration program for many years, many manufacturers have already canceled the registrations for thousands of pesticide products containing hundreds of active ingredients rather than pay the fees or develop the data required to support the products’ reregistration.

When new evidence indicates that a registered pesticide may pose a significant health or environmental risk, EPA conducts an extensive analysis, known as a special review, to determine whether the risks to human health or the environment exceed the benefits of continued use. Through this process, EPA has determined that a number of active ingredients—and the products containing these active ingredients—pose unreasonable risks to human health or the environment and has therefore canceled some or all registrations for the use of these pesticides. In many cases, a manufacturer facing special review has voluntarily canceled a pesticide’s registrations.

EPA Takes a Separate Action to Revoke Tolerances

In general, after a pesticide’s registration for a specific use has been canceled, the pesticide may no longer be sold or distributed for that use in the United States. However, as long as the pesticide’s tolerances remain in effect, foods containing residues of the pesticide may be sold in the United States. FDA and USDA may not classify such foods as adulterated and may not seize and remove them from commerce.

Neither FIFRA nor FFDCA requires EPA to revoke a pesticide’s tolerances after it has canceled the pesticide’s registrations. However, in 1982, after consulting with FDA and USDA, EPA adopted a policy on revoking the tolerances for canceled pesticides in which it stated that “when a pesticide’s registration for a food or feed use is canceled because of a concern about the safety of the pesticide, the associated tolerance . . . is no longer justified and logically should be revoked.” EPA added that “the agencies are concerned that having formal tolerances remaining in effect for canceled pesticides may serve to condone use of these pesticides in this country and/or in or on commodities imported from foreign countries.”

EPA May Recommend Action Levels for Monitoring Unavoidable Residues

Although most pesticides break down fairly quickly in the environment, some pesticides degrade very slowly and persist in the environment long after their use has ended. Hence, residues of these pesticides may be unavoidable in certain foods. To provide standards for regulating these unavoidable residues in foods, EPA recommends action levels, which FDA and USDA have agreed to establish for use in monitoring and enforcement, in accordance with EPA’s 1982 policy. In recommending action levels, EPA’s policy requires the agency to assess health risks as well as the extent to which residues are unavoidable in foods and to periodically lower action levels as residues of canceled pesticides decline in the environment.

Like a tolerance, an action level specifies the maximum amount of a pesticide’s residues that may be allowed in or on a food or feed. However, an action level is established only for residues that are considered unavoidable in a certain food. An action level may be established to take the place of a tolerance that has been revoked. An action level may also be established for a pesticide’s unavoidable residues in a food for which a tolerance was never set because the pesticide was never registered for use on that food. FDA issued a notice in the Federal Register (55 Fed. Reg. 14359, Apr. 17, 1990) explaining how the agency would use action levels. FDA stated that, according to FFDCA, “in the absence of a tolerance, any amount of a pesticide residue in a food or feed is unsafe and therefore renders the food or feed adulterated.” But when a food or feed is unavoidably contaminated with certain persistent pesticides that do not have tolerances, FDA said that it would use action levels to provide guidance for determining when enforcement action was warranted.

Most of the action levels that EPA has proposed or recommended have been for a group of chlorinated compounds—including DDT, chlordane, and dieldrin—that were widely used in U.S. agriculture during the 1950s and 1960s. Because these compounds were later found to pose unacceptable chronic health risks to humans and to affect reproduction and cause birth defects in wildlife, most of their registrations were canceled during the 1970s. However, unlike most pesticides, these compounds have not readily broken down. Today, they are still found in soil, sediment, and water.

Chlorinated compounds are not highly concentrated in plants, but they are accumulated in other organisms, particularly in fish, which are at or near the top of the aquatic food chain. Unlike the herbivorous land animals eaten by humans, fish are often predators. When they prey on other aquatic animals, they may ingest and accumulate compounds that their prey have already accumulated. According to EPA, aquatic organisms may accumulate environmental contaminants in concentrations up to 1 million times greater than are found in the surface water from which the organisms are taken. Although these chlorinated pesticides were never registered for use on fish, they have been found in fish for decades, largely because agricultural runoff transported the pesticides to the nation’s rivers and lakes. Since these pesticides did not have tolerances for fish, FDA established action levels as guidelines for determining when enforcement action was warranted.

According to EPA, most foods and feeds either contain no detectable residues of these canceled pesticides or contain residues that are well below the recommended action levels. Therefore, EPA believes that the dietary risk from these canceled pesticides in most foods is low. But because of the relatively high potential for these persistent pesticides to be concentrated in fish, health risks from dietary exposure to these canceled pesticides are greater in fish than in other foods.

EPA Has Established a Process for Revoking Tolerances and Recommending Action Levels

When EPA decides to revoke a pesticide’s tolerances, it first verifies that all of the registrations associated with these tolerances have been canceled. It then reviews monitoring data to determine whether and to what extent residues of the canceled pesticide remain in foods and whether action levels are needed to replace the existing tolerances. EPA also analyzes the economic impact of revoking tolerances on domestic food producers and on imported commodities. Then, EPA prepares and issues a preliminary notice in the Federal Register stating its intent to revoke certain tolerances and requesting comments from interested parties. If action levels are needed, EPA specifies what levels it intends to recommend to FDA or USDA. After the 60-day comment period has expired, EPA issues a final notice in the Federal Register announcing the effective date of the tolerances’ revocation and, if necessary, the final recommended action levels.

Objectives, Scope, and Methodology

Concerned that residues of canceled pesticides in food continue to pose a health risk to U.S. consumers, the Chairman, Environment, Energy, and Natural Resources Subcommittee, House Committee on Government Operations, asked GAO to (1) determine whether marketed foods contain unsafe levels of residues from canceled pesticides and (2) evaluate EPA’s procedures for revoking tolerances for canceled food-use pesticides.

To determine whether marketed foods contain unsafe levels of residues from canceled pesticides, we focused on health risks from fish contaminated with residues of five canceled pesticides—DDT, chlordane, dieldrin, heptachlor, and mirex. We focused on these five canceled pesticides because—unlike most other pesticides—they are highly persistent in the environment and because EPA, the National Academy of Sciences, and other organizations agree that they pose significant health risks through dietary exposure. We focused on fish because fish are more likely than most other foods to accumulate residues of these canceled pesticides. In addition, data on the health risks of residues from other canceled pesticides on food commodities are sparse. But data on the health risks of residues from these five canceled pesticides in fish were readily available because EPA had assessed these risks in response to concerns expressed by Members of Congress, EPA regional officials, and environmental organizations.

To evaluate EPA’s basis for proposing action levels for the residues of five canceled pesticides in fish, we reviewed EPA documents and Federal Register announcements on establishing action levels. We also reviewed EPA’s study of residue levels and health risks for these pesticides, as well as EPA’s analyses of the economic impact of lowering the action levels for residues of the five canceled pesticides in fish.

To determine the trends in residue levels for these canceled pesticides, we reviewed FDA’s pesticide monitoring data for fish and fishery products and FDA’s total diet studies for all food commodities, from 1984 through 1992, for detections of DDT, chlordane, and dieldrin. We compared the current action levels with the actual residue levels detected in fish tested by FDA. Specifically, we compared the current action level for dieldrin residues in whitefish with the average dieldrin residues that FDA detected in testing domestic whitefish from 1984 through 1992.

To demonstrate the effect of federal action levels on consumers of fish that are not tested by FDA because they do not enter interstate commerce, we interviewed EPA Office of Water officials and reviewed EPA studies on (1) the basis that states use to establish fish advisories, (2) the levels of contamination from pesticides and other chemicals that are found in fish nationwide, and (3) the guidance that the Office of Water provides to states on establishing fish advisories. We also examined a 1991 National Academy of Sciences study of seafood safety, which discusses the extent to which fish are contaminated by pesticides and other chemicals and the actions that are needed to better inform consumers of the potential risks of eating certain fish. In addition, we contacted several state health and environmental officials to find out how federal action levels affect their regulation of pesticides in fish and to determine the extent of their efforts to monitor these pesticides.

To evaluate EPA’s process for revoking the tolerances for canceled pesticides, we interviewed key EPA officials who either were or had been involved in the revocation process, and we collected documents explaining EPA’s revocation policy and procedures and showing the status of EPA’s revocation efforts. We also examined the Federal Register notices for all pesticides whose tolerances had been revoked as of July 1994 to determine how many tolerances had been revoked and how much time had elapsed between cancellation and revocation. In addition, we reviewed EPA documents and information systems to determine how many canceled pesticides still have tolerances. When we reviewed data from EPA’s information systems on canceled food-use pesticides, we found that much of the information was unreliable and, therefore, could not be used. To identify canceled food-use pesticides that still have tolerances, we examined EPA planning documents and reregistration status reports and asked EPA officials to verify the information. In addition, we examined FDA fiscal year 1992 monitoring data to determine whether some canceled pesticides that still had tolerances were appearing in the U.S. food supply.

We conducted our review between April 1993 and September 1994 in accordance with generally accepted government auditing standards.

We discussed the facts and analysis presented in this report with responsible officials from EPA—including the Deputy Assistant Administrator, Office of Prevention, Pesticides, and Toxic Substances; the Deputy Director, Office of Pesticide Programs; and the Director, Policy and Special Projects Staff, Office of Pesticide Programs—and from FDA—including the Deputy Associate Commissioner for Regulatory Affairs; the Director, Office of Policy, Planning, and Strategic Initiatives, Center for Food Safety and Applied Nutrition; and the Director, Contaminants Policy Staff, Office of Regulatory Affairs. These officials generally agreed with the information presented but suggested a number of technical and editorial changes that we incorporated where appropriate. As requested, we did not obtain written agency comments on a draft of this report.

Unsafe Residues May Be Present in Some Fish

According to EPA, most pesticides break down fairly quickly in the environment and therefore do not appear at significant levels in most foods. But a few pesticides whose registrations were canceled about 20 years ago have persisted in the environment. EPA believes that residues of these pesticides are present at low levels in most foods. However, they are found in some fish at levels that exceed EPA’s usual negligible risk standard. The action levels currently used to regulate residues of these canceled pesticides in fish do not meet criteria in EPA’s 1982 policy because they (1) are not based on an assessment of health risks and (2) have never been adjusted to reflect declines in residue levels that have occurred since FDA first set the action levels in the late 1960s and early 1970s.

In 1991, after conducting a study that evaluated health and economic effects and more recent residue data, EPA proposed lower action levels to FDA. While FDA agreed that action levels should be lowered to reflect declines in residues of these pesticides in fish, it believed that EPA’s proposed levels would represent too great a reduction. Despite their shared belief that action levels should be lowered, neither agency has since taken any action to reach agreement on appropriate lower action levels.

EPA’s Policy Requires Assessment of Health Risks and Declines in Residues

In its 1982 policy on revoking the tolerances for canceled pesticides, EPA established principles for recommending action levels to FDA and USDA that emphasized the importance of assessing health risks and actual residue levels in food. Under the policy, action levels would “be set limiting the quantity of a pesticide in or on food commodities to the extent necessary to protect the public health.” Although action levels would “tak into account the extent to which the contaminant is unavoidable,” they would be “sufficient to protect the public health.” In some instances, according to the policy, the health risk for a given pesticide could be so great that no residue level would be acceptable. In these instances, the policy calls for EPA to recommend action levels that do not exceed levels that FDA can detect using its current testing methods. Finally, the policy stated that EPA would periodically review action levels and lower them as residues of canceled pesticides in food declined.

Current Action Levels Are Not Based on EPA’s Policy Criteria

In 1985, EPA placed preliminary notices in the Federal Register announcing its intention to revoke the tolerances for DDT, chlordane, and dieldrin, whose registrations for food uses it had canceled during the 1970s. Because these pesticides’ residues persisted in the environment, EPA, in accordance with its 1982 policy statement, also proposed action levels to replace the revoked tolerances. For fish, EPA proposed to retain the action levels that FDA had been using since the late 1960s and early 1970s.

EPA Based 1985 Action Level Proposals on Old Residue Data

In developing the action levels that it proposed for DDT, chlordane, and dieldrin in 1985, EPA primarily reviewed residue data from the 1970s, which indicated that residue levels in fish had not declined much since the action levels were originally established. In addition, EPA did not assess the health risks posed by these residues, as directed in its 1982 policy. In response to concerns about DDT expressed in a 1986 congressional hearing, EPA said that it had not assessed health risks when it proposed action levels to replace the tolerances or existing action levels for this pesticide. Instead, EPA reviewed FDA’s pesticide monitoring data and proposed action levels that reflected the actual levels of DDT residue found in foods monitored during the late 1970s.

EPA officials told us that the proposed action levels for DDT and other chlorinated pesticides were set at a level high enough so that most—about 95 percent—of the residues found in foods would be at or below the action levels. EPA reasoned that the residues of these canceled pesticides were unavoidable and had not entered the food supply through the misuse of pesticides. Therefore, the agency did not want to penalize food producers for past legal uses of the pesticides.

In response to its preliminary notices, EPA received no significant comments on the adequacy of the action levels it had proposed for foods other than fish. But a number of commenters—including two EPA regions—questioned the safety of the action levels proposed for fish. EPA’s Region VII noted that EPA apparently had not reviewed available health effects data, as required by its 1982 policy, to assess the safety of the proposed action levels. Similarly, EPA’s Region V commented that EPA had not assessed the effects of the proposed action levels on human health. According to several commenters, the risk of cancer under the proposed action levels was far greater than the agency’s risk standards usually allowed. For example, although EPA typically applies a negligible risk standard for cancer when regulating pesticides in food, EPA’s Region VII stated that the risk of cancer under the proposed action level for chlordane was 1 in 22,000, and the National Wildlife Federation estimated that the risk of cancer for dieldrin was 1 in 1,000.

In commenting on the proposed action levels for fish, FDA maintained that the existing action levels might need to remain in effect because high levels of DDT residue were still being found in fish from at least one part of the United States. But FDA also said that EPA needed to study the health effects of these pesticides in light of the comments it received on its proposed action levels.

In 1986, EPA issued final notices in the Federal Register in which it revoked the tolerances for DDT, chlordane, and dieldrin in foods other than fish and recommended action levels to replace the tolerances. But in response to concerns over the level of risk that would still be allowed under the proposed action levels for residues of these three canceled pesticides in fish, EPA announced that it would wait to recommend action levels for fish until it could obtain updated residue data and assess the health effects of alternative action levels. Later, EPA added two other canceled pesticides—heptachlor and mirex—to its study of action levels for fish (see app. I).

EPA Conducted a Study to Assess Recent Residue Data, Health Risks, and Economic Effects

To determine whether action levels should be revised, EPA conducted a study in which it reviewed recent residue data and evaluated health risks, as prescribed in its 1982 policy. In addition, EPA evaluated the economic effects of lower action levels.

To conduct its study, EPA obtained recent exposure information by collecting national and regional data on residues of DDT, chlordane, dieldrin, heptachlor, and mirex in fish and compiled a data base from tests of about 11,000 samples conducted between 1983 and 1987 by FDA, EPA regions, state agencies and other federal agencies. Using these data, EPA estimated the risk of cancer to consumers of fish at various action levels.

To assess the economic effects of alternative action levels for fish, EPA projected the percentage of the fish catch that would exceed lower action levels and estimated the costs to commercial fisheries of not being able to sell these fish.

EPA’s Study Showed Lower Residue Levels

EPA’s analysis of the monitoring data showed that, for the five canceled pesticides, residue levels in fish generally appeared to be declining. However, in certain locations, residue levels appeared to remain constant or to increase over time. EPA attributed the apparent increases in residue levels in fish to the occasional stirring up of sediment and releasing of residues from the sediment into the water or to methodological issues, such as variation in the size of the fish sampled and nonrepresentative sampling. But EPA said that action levels could be lowered to reflect the generally declining levels of these pesticides’ residues in fish.

We examined FDA’s records of dieldrin detections in whitefish from 1984 through 1992 to determine the trends in residue levels. As shown in figure 2.1, FDA’s records indicate that residue levels declined from an average of 0.313 parts per million (ppm) in 1984 to 0.120 ppm in 1992. Since 1984, average dieldrin residue levels have been consistently below the current action level of 0.3 ppm. However, FDA’s records also show that between 1990 and 1992 residues of dieldrin in fish have remained steady or have increased slightly. According to EPA officials, this slower rate of decline indicates that despite the general decline in residues of canceled chlorinated pesticides in fish, these residues may continue to appear at significant levels in some fish for a number of years to come.

EPA’s Office of Pesticide Programs calculated the risks of cancer at current action levels to consumers of average amounts of fish that are sold in interstate commerce and that contain average levels of the five canceled pesticides’ residues. These calculations, presented in table 2.1, were based on national and regional data collected by EPA from federal agencies, states, and EPA regions. EPA’s analysis of the data showed that, at current action levels for the five pesticides, the dietary risks of cancer exceed the agency’s usual standard of negligible risk (1 in 1 million).

According to EPA, the figures shown in table 2.1 could either overestimate or underestimate risks, depending on the extent to which actual exposure differs from the assumptions used in the calculations (see note following table 2.1). For consumers of average amounts of fish sold in interstate commerce, the figures may significantly overstate risks. For example, for dieldrin, EPA said that if it had used less conservative assumptions for samples in which no residues were detected, the risks calculated for this pesticide would have been only 2 in 1 million rather than 100 in 1 million. According to EPA, more accurate estimates of risk were not possible using available data.

But EPA also noted that the actual risks could be considerably higher than the average risks shown in the table for consumers of larger amounts of fish or of fish that are more highly contaminated with residues of these pesticides. For example, although the calculations of risk in table 2.1 assume consumption of 15 grams of fish per day, EPA has estimated that typical recreational fishermen consume 30 grams per day and subsistence fishermen consume 140 grams per day, on average. These levels of consumption are about two to nine times greater than the levels EPA used to calculate the risks shown in table 2.1. Because risks are proportional to consumption, consumers of larger amounts of fish could be exposed to proportionately higher risks than are shown in the table.

EPA Estimated the Economic Effects of Lower Action Levels

EPA computed the economic costs to commercial fisheries of implementing lower action levels, taking into account the estimated loss of nationally and regionally important fish species. The agency calculated a potential annual economic loss to commercial fisheries of either $74.3 million or $272.7 million, depending upon the action levels considered and assuming that FDA would identify and remove from commerce all fish that exceeded the action levels. For fish species considered to have national or local economic importance, EPA also estimated the percentage of fish that would exceed the current action levels and the lower action levels. These estimates indicated that a significantly greater percentage of fish would exceed the proposed lower action levels than would exceed the current action levels. For example, although none of the herring catch would exceed the current action level for dieldrin, 17 percent of the catch would exceed the lower action level for dieldrin that EPA proposed in 1991. Similarly, while 17 percent of the sablefish catch would exceed the current action level for DDT, 25 percent would exceed the proposed lower action level.

EPA’s Study Indicated Lower Action Levels

In 1991, after reviewing its data on residues of the five pesticides in about 11,000 fish samples, assessing the health risks of each pesticide, and calculating the economic costs to commercial fisheries of implementing alternative action levels, EPA sent FDA a draft proposal to lower the action levels for residues of DDT, chlordane, dieldrin, heptachlor, and mirex in fish. These lower action levels are presented in table 2.2 along with the current action levels used by FDA. EPA officials told us that these action levels represent the agency’s balancing of health and economic effects, taking into account the unavoidability of these residues in fish.

EPA and FDA Have Not Agreed on Lower Action Levels for Fish

One year after EPA sent the draft proposal, EPA and FDA officials met to discuss these action levels. According to EPA’s Deputy Assistant Administrator for Prevention, Pesticides, and Toxic Substances, staff from both agencies believed that residues of the five pesticides had been declining in the environment and that lower action levels would therefore be appropriate. FDA agreed to review its pesticide monitoring data to see how much residues had declined and whether its data could support the lower action levels proposed by EPA.

In September 1992, FDA concluded, after reviewing its monitoring data for 1989 to 1991, that EPA’s lower action levels would greatly decrease the allowable catch from the Great Lakes and a number of southern and western states. FDA said that EPA would therefore have to demonstrate and document the need for the lower action levels to protect consumers and show that the lower levels took into account the unavoidability of residues in fish.

In May 1994, the Director of FDA’s Contaminants Policy Staff told us that EPA did not justify its proposed action levels to FDA. He said that FDA believes that residues of canceled chlorinated pesticides in fish have generally declined since the action levels were originally established and that the action levels should be lowered to reflect this decline. But, according to the official, EPA’s proposed lower action levels were significantly lower than they would be if they were based only on declines in residues in fish. Therefore, FDA needed adequate justification to explain to consumers and commercial fisheries the basis for the stricter standards and their potential economic impact.

In May 1994, the Director of EPA’s Pesticide Registration Division told us that because of budgetary constraints, EPA has no foreseeable plans to obtain additional documentation to satisfy FDA’s concerns. He said that EPA considers its data sufficient to justify the lower action levels. However, EPA has not formally recommended the lower action levels to FDA. Hence, despite their agreement that the action levels should be lowered, neither agency has taken the initiative to reach agreement on appropriate lower action levels.

Many States Use Federal Action Levels to Regulate Fish

Although federal action levels are based on national rather than regional or local data, many states use the federal action levels as their basis for determining when to issue fish consumption advisories. In 1990, EPA’s Office of Water reported that two-thirds of the states (34) were using federal action levels as their basis for evaluating the safety of chemical contaminants in fish. Other states were using a risk-assessment approach derived from EPA’s criteria or had developed their own approach.

According to a 1991 National Academy of Sciences report on seafood safety, fish caught for recreation or subsistence may pose greater health risks than fish sold in interstate commerce because such fish are more likely to be caught near areas contaminated with hazardous chemicals (including pesticides) and may be consumed in greater quantities by certain subpopulations. The Academy reported that recreationally harvested fish may represent over one-fifth of the fish consumed in the United States and that these fish are caught by an estimated 17 million recreational fishermen.

The Academy noted that state regulatory agencies are almost exclusively responsible for issuing seafood health advisories. But it said that states depend heavily on federal guidance in regulating seafood, and this guidance may not take into account specific regional variations in seafood safety. The Academy suggested that “a more consistent and focused effort in the determination and communication of public health risks from contaminated seafood should be developed” and that “a more pronounced and consistently defined federal role in the risk characterizations leading to these advisories would be .”

In 1992, EPA’s Office of Water completed a study of chemical residues in fish that revealed widespread contamination by pesticides and other chemicals in fish. Concerned about this contamination and about states’ inconsistent procedures for sampling fish and issuing fish consumption advisories, the Office of Water issued guidance to the states in 1993 and 1994 to assist them in developing a risk-based approach for monitoring fish and determining when fish advisories should be issued (see app. II for more detailed information on the study and guidance). Office of Water representatives told us that it was too soon to evaluate the impact of this guidance. They did not know of any states that had used the guidance to strengthen their monitoring standards for pesticides’ residues in fish.

An Office of Water official also said that a number of states are not active in monitoring fish and issuing fish advisories, principally because they lack funding. He said that other states, such as New York, recognize that the federal action levels are designed for FDA’s regulation of fish in interstate commerce but nevertheless continue to use the federal action levels in their own regulatory programs.

A New York State environmental health official told us that although her agency believes that a risk-based monitoring approach would protect consumers’ health better than action levels, the agency is reluctant to move toward risk-based monitoring. The official explained that New York has a number of commercial fisheries whose catches are subject to FDA’s monitoring. Because pesticides and other chemicals in these fish do not generally exceed the federal action levels, the fish are sold legally in interstate commerce. The official said that, in view of FDA’s monitoring, the state believes that it would face an untenable position if it were to adopt more stringent risk-based monitoring standards for fish caught and consumed within the state. At the same time as the state was trying to justify stricter standards for fish that would be caught and consumed within New York, the official said, FDA would be allowing the same species of fish, with the same levels of chemical contamination, to be sold nationwide without any warnings or advisories.

EPA’s Region V also noted that a number of states are reluctant to apply different state and federal standards in monitoring the safety of pesticides’ residues in fish. The region is concerned that if the action levels for pesticides’ residues in fish are not lowered, then the states will not issue more protective fish consumption advisories.

The Director of FDA’s Contaminants Policy Staff agreed that states might have difficulty explaining differences between federal and state monitoring levels to local consumers and commercial fisheries. Nevertheless, he said that FDA could not set enforcement limits for local conditions because the action levels enforced by FDA apply nationwide to fish in interstate commerce. The Director noted that a state or locality might issue guidance on the amount of contaminated fish that consumers might eat without appreciable risk to their health.

Conclusions

Although EPA believes that residues of the five persistent pesticides that it studied do not appear in most foods at significant levels, it has found that they appear in some fish at relatively high levels. The current action levels for these pesticides in fish, which FDA established about two decades ago, are based on residue levels found in the environment at that time. They have not been adjusted to reflect health risk assessments or subsequent declines in residue levels. Consequently, they are not consistent with the 1982 policy that calls upon EPA, when recommending action levels, to assess health risks as well as unavoidable residues and to revise its recommendations periodically as residue levels decline.

The action levels that EPA proposed to FDA in 1991 are based on EPA’s assessment of residue data, health risks, and economic effects. Hence, these action levels were developed in accordance with the requirements of the 1982 policy. Both EPA and FDA agree that the action levels should be lowered but disagree on the extent to which they should be lowered on the basis of available data. We do not believe that the differences between EPA and FDA over the sufficiency of EPA’s data should block attempts by the agencies to reach agreement on appropriate action levels. Reaching agreement on appropriate action levels would help to ensure that consumers of both federally monitored and state-monitored fish are being adequately protected.

Recommendations

To protect consumers from unreasonable exposure to the residues of canceled pesticides, we recommend that the Administrator of EPA and the Commissioner of FDA work together to determine, on the basis of the most recent data, the appropriate action levels for residues of the five canceled chlorinated pesticides in fish. We also recommend that the Administrator of EPA periodically reevaluate and lower action level recommendations to reflect decreases in environmental residue levels.

Agency Comments

EPA and FDA officials generally agreed with the information presented in this chapter but suggested a number of technical and editorial changes that we incorporated where appropriate. In particular, EPA officials believed that our presentation of EPA’s data on health risks posed by residues of canceled chlorinated pesticides in fish overstated the health risks. We revised our presentation of EPA’s data to highlight the uncertainties in the data and to include only the information that EPA considered to be the most valid.

We also discussed with these officials the potential effectiveness of the actions that we recommend in this report. The EPA officials agreed that actions such as we recommend are necessary to resolve the problems we identified in connection with action levels. The FDA officials agreed with the thrust of our recommendations on action levels.

EPA Is Slow to Revoke Tolerances for Canceled Pesticides

In canceling the registrations for many food-use pesticides during the past two decades, EPA has not concurrently revoked the related tolerances for these pesticides. Although EPA has recently taken action to revoke the tolerances for some older canceled pesticides, an undetermined but potentially large number of canceled pesticides still have tolerances.

On average, EPA has taken over 6 years to revoke a pesticide’s tolerances after canceling the pesticide’s registrations. Although part of this delay is intended to allow food treated with remaining stocks of a canceled pesticide to clear the channels of trade, a greater part is attributable to the low priority that EPA has assigned to revocation and to the absence of procedures linking revocation to cancellation.

As long as the tolerances for canceled pesticides remain in effect, foods containing allowable amounts of these pesticides’ residues can legally enter the U.S. food supply. FDA and USDA cannot consider such foods adulterated and cannot take enforcement action against them.

Many Tolerances Have Been Revoked, but Many More Remain

Over the past few years, EPA has stepped up efforts to revoke the tolerances for pesticides whose registrations for food uses were, for the most part, canceled during the 1980s. As of July 1994, EPA had revoked the tolerances for 50 canceled pesticides and had formally proposed to revoke the tolerances for 31 canceled pesticides (see apps. III and IV). According to EPA officials, these revocations have dealt with the major pesticides that pose a dietary risk to the public, such as DDT, chlordane, and toxaphene. Most of these revocation actions occurred during the past 2 years.

EPA has not been able to determine how many more canceled pesticides have tolerances that should be revoked because its data bases do not identify all pesticides whose registrations for some or all food uses have been canceled. But an EPA official responsible for revocations estimated that over 100 pesticides may fall into this category and that hundreds of associated tolerances remain in effect for these canceled pesticides. This official believes that the food-use registrations for most of these pesticides have been canceled for over 2 years.

In the past, EPA tried to define the universe of canceled pesticides that still had tolerances to be revoked. For example, in early 1992, EPA identified 98 pesticides whose tolerances it considered “probable” candidates for revocation. Over 2 years later, EPA has not begun to revoke the tolerances for nearly half of these pesticides, and the agency is again attempting to identify the canceled pesticides that still have tolerances to be revoked.

Though difficult to determine because of deficiencies in EPA’s data bases, the number of canceled pesticides that still have tolerances may be sizable. From EPA’s List A—the group of pesticides assigned the highest priority for reregistration—we identified 10 pesticides whose registrations for food uses were all canceled between 3 and 13 years ago. There are 185 tolerances that remain in effect for these canceled pesticides. For one of the pesticides, cyhexatin, all of the registrations were canceled voluntarily by its manufacturers in 1987 after EPA considered initiating a special review in response to concerns over the pesticide’s potential to cause birth defects. However, as of July 1994, EPA had not begun to revoke cyhexatin’s tolerances.

As of April 1994, EPA had evaluated approximately 100 out of about 600 active ingredients that are undergoing reregistration. As it continues its evaluations through reregistration and special review, the registrations for other pesticides are likely to be canceled and their tolerances will then need to be revoked.

EPA Assigns Revocation a Low Priority and Has No Procedures Linking Revocation to Cancellation

Since 1982, when it issued its policy on revoking tolerances, EPA has taken over 6 years, on average, to revoke a pesticide’s tolerances after canceling the pesticide’s registrations. Typically, the agency has allowed some time—usually about 2 years—for remaining stocks of a pesticide to be used and for products legally treated with the pesticide to move through commerce. But most of the delay in revocation can be attributed to both the low priority that EPA has assigned to revocation and the absence of procedures linking revocation to cancellation. The regulatory history of the pesticide bufencarb illustrates this pattern: Although EPA had canceled all registrations for food uses of bufencarb by April 1986, it did not propose to revoke the related tolerances until August 1992, and it did not complete their revocation until June 1993, over 7 years later.

EPA Assigns Low Priority to Revocation

EPA assigns low priority to revoking tolerances, in part because revocation is not required by law. When the agency first canceled registrations for food-use pesticides during the 1970s, it had no mandate or guidance directing it to revoke the related tolerances. Although EPA’s 1982 policy established the principle that revocation should coincide with cancellation, it created no time frames for revocation or impetus for linking revocation to cancellation.

EPA officials told us that the agency assigns low priority to revoking tolerances because many of the food-use pesticides have been canceled voluntarily or pose little or no dietary risk. But the fact that a pesticide has been canceled voluntarily does not necessarily mean that it poses no dietary risk. In addition, EPA has delayed revocation for almost all pesticides, including those considered to pose dietary risks. For example, long-term exposure through the diet to the pesticide heptachlor could cause cancer in humans, according to EPA, yet the agency revoked the tolerances for this pesticide more than 11 years after canceling its registrations for food uses.

The low priority assigned to revocation is reflected in the limited resources allocated to it. The EPA official responsible for revocation said that none of the 13 staff in her unit works full-time on revocation actions and slightly fewer than 3 full-time-equivalent staff per year are allocated for such actions. According to this official, her unit has so many other higher-priority responsibilities that it can handle only a limited number of revocation actions at one time. While recognizing that the tolerances for many other canceled pesticides still required revocation, she said that she currently did not have the time available to identify these pesticides. Most of the EPA personnel involved in revocation told us that revocation activities have a lower priority than their other responsibilities.

To conserve the limited resources that it has allocated to revocation, EPA usually delays the revocation of a pesticide’s tolerances until it has canceled all of the pesticide’s registrations for all of its food uses. Thus, it avoids taking multiple revocation actions for a single pesticide. For example, EPA canceled all registrations for insecticidal uses of the pesticide sodium arsenite in 1988 because of concerns about the pesticide’s toxic effects on workers and the general public. But the agency did not propose to revoke the tolerances for these uses until the registration for one remaining food-use—as a fungicide on grapes—was canceled in 1992, about 4 years later.

EPA Does Not Have Formal Procedures for Linking Revocation to Cancellation

Despite its policy supporting a link between revocation and cancellation, EPA has not developed written procedures or guidelines specifying when it should revoke a pesticide’s tolerances for canceled food uses. As a result, the agency has taken anywhere from a few months to over 14 years to revoke the tolerances for individual pesticides. Without such procedures, EPA is under no pressure to revoke tolerances in a predictable or consistent way.

In addition, EPA has no written procedures or guidelines requiring the officials responsible for handling cancellations to notify the officials responsible for revoking the related tolerances of any cancellations. Consequently, the personnel responsible for revocations often do not receive information about cancellations on a timely and consistent basis and in a standard format that provides all of the information needed to revoke tolerances. Without reliable channels of information and communication between the personnel responsible for cancellations and the personnel responsible for revocations, EPA cannot effectively implement its policy linking revocation to cancellation.

EPA officials acknowledge that the agency’s current process for revoking tolerances takes too long and is inefficient. According to the officials, the establishment of a process linking revocation to cancellation would help ensure that the tolerances for canceled pesticides are revoked in a timely manner. Furthermore, the officials said that taking revocation and cancellation action concurrently would generally result in the more efficient use of EPA’s resources than the current revocation process. They emphasized that although the revocation action could occur at the same time as the cancellation action, EPA would need, when establishing an effective date of revocation, to give growers enough time to use exisitng stocks of the canceled pesticide.

Enforcement Agencies Cannot Take Action Against Foods Containing Residues of Canceled Pesticides

As long as the tolerances for residues of canceled pesticides remain in effect, FDA and USDA can do nothing to prevent foods containing allowable amounts of these chemicals from entering the U.S. food supply. Although a pesticide’s residues usually decline or disappear in domestic foods within a few years after the pesticide’s registrations have been canceled—except when the pesticide persists in the environment—the pesticide’s residues may continue to appear in imported foods. U.S. and foreign manufacturers may continue to sell the canceled pesticide for use on crops abroad, and the food grown abroad may be sold in the United States as long as the pesticide’s residues do not exceed the tolerances.

Determining the extent to which canceled pesticides that still have tolerances appear in foods is difficult, not only because EPA has not identified all of these pesticides but also because FDA monitors residues selectively. Nevertheless, in reviewing FDA’s 1992 monitoring data, we found that FDA had detected demeton, a pesticide whose registrations were canceled nearly 5 years ago, seven times on four different food commodities that still had tolerances. Because the tolerances for demeton had not been revoked, FDA did not consider the foods containing the pesticide to be adulterated.

Similarly, assessing the health risks posed by canceled pesticides that still have tolerances is difficult. Information on the health risks of many canceled pesticides is limited because EPA’s data bases are incomplete or because the registrant voluntarily canceled the registrations before EPA finished assessing the pesticide’s health risks. For example, after the registrations for food-uses of the pesticide tetrachlorvinphos (a possible human carcinogen) were canceled in 1987, EPA stated that it did not have sufficient scientific data to evaluate the safety of the pesticide’s tolerances—which were established under less stringent scientific standards in the early 1970s. Despite this uncertainty about the pesticide’s dietary risks, EPA did not propose to revoke the pesticide’s tolerances until 1994—about 7 years after the associated food-use registrations were canceled.

For some canceled pesticides that still have tolerances, available data indicate a potential to harm humans. For example, the pesticide monocrotophos is a potent cholinesterase inhibitor (linked to nervous system problems) and is toxic to fetuses. Another pesticide, captafol, is classified by EPA as a probable human carcinogen. Both of these pesticides were voluntarily canceled 6 or more years ago, but EPA has not yet revoked their tolerances, although it proposed to do so in June 1993.

Conclusions

Because EPA has not consistently or expeditiously revoked the tolerances for many canceled pesticides, residues of these pesticides have been allowed to appear legally in the food supply, often for many years after the pesticides’ domestic uses were prohibited. Although EPA believes that it has revoked the tolerances for most of the older, higher-risk canceled pesticides, it still needs to identify and revoke the tolerances for a substantial number of other canceled pesticides.

By revoking the tolerances for canceled pesticides and, in the future, conducting revocation and cancellation actions concurrently, EPA would be acting consistently with its 1982 policy statement. In addition, it would be streamlining its process for revoking tolerances and eliminating the potential for residues of the same pesticides that it has deemed unacceptable for use on crops to appear legally in food.

Recommendations

To expedite the revocation of tolerances for canceled pesticides and make more efficient use of scarce resources, we recommend that the Administrator, EPA, establish procedures for concurrently conducting tolerance revocation and cancellation actions and, when necessary, set an effective date for revocation that gives growers enough time to use existing stocks of the canceled pesticide and identify the pesticides whose registrations for food uses have already been canceled and revoke their tolerances.

Agency Comments

EPA officials generally agreed with the information presented in this chapter but suggested a number of technical and editorial changes that we incorporated where appropriate. The officials agreed that actions such as we recommend are necessary to resolve the problems we identified regarding tolerance revocations.