Pesticides – An Overview

Background

Pesticides are chemical substances used to prevent, destroy, repel, or mitigate undesirable organisms such as weeds or harmful insects. The chemical control of pests has facilitated the industrialization of agriculture and has helped the United States reap a surplus of agricultural products. Used properly, pesticides by definition are inherently toxic to certain organisms. This inherent toxicity requires careful regulation to ensure the safety of the public, the food supply, and the environment. The United States Environmental Protection Agency (EPA) is the primary entity charged with regulation of pesticides, although it works in conjunction with state agencies. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. §§ 136-136y, establishes the general system of federal pesticide regulation, and the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. §§ 301-399i, establishes the system to govern pesticides in food and feed. States are generally permitted to enact legislation that restricts pesticide use beyond what federal law requires, although there are limitations. This overview focuses on FIFRA and FFDCA as amended by the Food Quality Protection Act of 1996 (FQPA), Pub. L. No. 104-170, 110 Stat. 1489.

The Office of Pesticide Programs (OPP) within the EPA manages the regulations of all pesticides and establishes maximum levels of pesticide residue that can be found in food or feed crops. The OPP implements FIFRA, FQPA, FFDCA, the Pesticide Registration Improvement Extension Act of 2018 (PRIA 4), and the Endangered Species Act. In addition to the regulatory functions, the OPP provides information and coordinates with partners and stakeholders on issues ranging from worker protections to the misuse of pesticides.

Federal Regulatory Authority

Administrative agencies such as USDA/FDA/EPA have been given authority by Congress to create regulations implementing the requirements of federal pesticide laws.  In 2024, the Supreme Court of the United States issued two rulings that are expected to have a major impact on how judges decide cases challenging those regulations and overall agency authority.

Loper Bright Enters. v. Raimondo, 144 S. Ct. 2244 (2024) overruled the long-standing doctrine of deference established in Chevron, U.S.A., Inc. v. Nat. Res. Def. Council, Inc., 467 U.S. 837 (1984). Chevron deference was a two-step process that clarified how and when federal courts should defer to an agency regulation interpreting a statute.  Chevron only applied in situations where a court had determined that the statutory language the agency was interpreting was ambiguous.  If it was ambiguous, the court would consider whether the agency’s interpretation of the statutory language was “reasonable”.  If it was reasonable, the court was required to defer to the agency’s interpretation. If it was not, the court would overrule the interpretation.

Loper Bright formally overturned Chevron. In a 6-3 decision, the Supreme Court held that “courts may not defer to an agency interpretation of the law simply because a statute is ambiguous[.]” Following the ruling, courts are instead required to exercise independent judgment in determining whether an administrative agency has acted within its statutory authority.  Courts may still seek guidance from the agencies involved, but courts will no longer be required to defer to an agency’s interpretation of a statute.

In Corner Post, Inc. v. Bd. of Governors of the Fed. Rsrv. Sys., 144 S. Ct. 2440 (2024), the Supreme Court extended the period of time during which a party may file a lawsuit challenging federal agency actions. According to federal law,  civil actions against the United States must be filed within six years after “the right of action first accrues” and that that agency actions can only be subject to judicial review after they are “final.” 28 U.S.C. § 2401(a); 5 U.S.C. § 704. Previously, this language was interpreted to mean that if someone wanted to challenge an agency regulation in court, they had to so within the six years after the regulation became “final.” Lawsuits filed outside that statute of limitations would not be heard.  However, in Corner Post, the Supreme Court ruled that an action becomes “final” when a plaintiff suffers an injury, rather than when a “final regulation” is released. This ruling expands the potential for plaintiffs to challenge federal agency rules and regulations that have been final for over six years.

While the full effect of these two rulings remains to be seen, it is highly likely that the agricultural industry will be impacted by the Supreme Court’s decisions. Importantly, the rulings fundamentally change how courts will resolve lawsuits challenging agency regulations for misinterpreting the agency’s statutory authority. Impacts are most likely to be felt in areas of the law, such as pesticides, dominated by statutes with relatively ambiguous language where Congress has relied on agency regulations to fill in specifics.

Federal Insecticide, Fungicide, and Rodenticide Act

The EPA regulates pesticides through registration and labeling requirements. A pesticide may not be sold in the United States until the EPA has registered the pesticide under FIFRA by approving a label that provides information on how to safely use and handle the pesticide. As part of the registration process, manufacturers must submit scientific data on pesticide toxicity and environmental behavior. If a pesticide will be used on a food or feed crop, data must be supplied to identify scientific methods that will detect the pesticide or its residues on food and specify the acceptable amounts that may be present in the food.

A cost-benefit analysis of the scientific data based on environmental, societal, and economic variables is used by the EPA to determine the acceptable uses and conditions for use, if any, of the pesticide. During the analysis, the EPA must determine whether the pesticide will cause “unreasonable risk to man or the environment[.]” The pesticide will only be registered if the EPA finds that use of the pesticide will not cause such a risk. Once registered, the manufacturer must prepare a label that meets EPA requirements in part by explaining the permissible uses and required conditions for use of the pesticides, including protections for workers. Pesticide label requirements preempt state and local laws, and application of a pesticide inconsistent with the label instructions is a violation of federal law.

In addition to general pesticide registrations, FIFRA authorizes procedures for temporary registrations, minor use registrations, experimental use registrations, special local registrations, and emergency use registrations. The EPA may grant a temporary registration to a pesticide if the evidence shows that the registration would be “in the public’s best interest” and would “not cause a significant risk to human health or the environment.” Minor uses are pesticide applications on crops with fewer than 300,000 acres of total production in the United States. These minor use applications play a major role in agricultural production and protect public health from disease vectors such as mosquitoes, ticks, cockroaches, rats, and disease-causing organisms. The small market for these minor use pesticides do not provide the economic incentive for chemical manufacturers to continue to fund their registration. Minor use provisions in FIFRA expedite minor use registrations by reducing registration costs and coordinating EPA actions with the United States Department of Agriculture (USDA), the Department of Health and Human Services, and producer groups that benefit from the registration of the minor use. Experimental use registrations allow companies to conduct research with pesticides to develop the required data for the registration process, and they allow agricultural research institutions to conduct other scientific experiments with the pesticides. Special local use registrations allow states to add permissible uses to pesticide labels for special local needs within a state. “Special local need” is defined to mean any existing or imminent pest problem for which the lead state agency has found that other federally registered pesticides will not sufficiently address. In the past, states have also used special local use registrations to add cut-off dates for applying certain pesticides. However, the EPA has stated that it will no longer issue special local use registrations that restrict the use of a pesticide beyond what is allowed in its registered label. Emergency use registrations, also called Section 18 registrations, allow states or federal agencies to make unregistered uses of pesticides to address emergency conditions. The uses allowed by an emergency use registration are limited to defined geographic areas, and to a specific length of time necessary to control the emergency situation. The maximum duration of an emergency use exemption may be one year for specific or public health exemptions, three years for quarantine exemptions, or 15 days for crisis exemptions. The EPA evaluates and makes decisions on the requests for emergency exemptions within 45 days.

During registration, the EPA determines if a pesticide will be classified either as a general use pesticide or a restricted use pesticide. A general use pesticide is considered “safe enough to be used by the general public.” Restricted use pesticides can only be applied by certified users because they are considered “more dangerous.” Most states have developed programs approved by the EPA to train and certify applicators for restricted use pesticides.

Special review provisions in FIFRA allow the EPA to reevaluate registered pesticides. Registrants are required to submit new evidence if EPA has reason to believe that use of the pesticide may be causing adverse effects to people or the environment. Registrants may be required to submit additional data and undertake new studies to assist the review. After completion of the special review process, the EPA may choose to continue the registration, amend the registration, or cancel the registration depending on the findings.

In addition to the special review process, the EPA reviews each registered pesticide at least once every 15 years to ensure that they continue to meet the FIFRA standard for registration. When this 15-year review program was established, the EPA determined that those pesticides which had been originally registered before November 1, 1984, would be the first to receive review. The 15-year review process can sometimes take several years and can lead to a special review in which the registration is amended or cancelled.

Cancellation of a pesticide registration makes future sale or distribution of the pesticide illegal but may allow the sale and use of existing stocks if doing so would not violate the purposes of FIFRA. A pesticide cancellation may be initiated by the EPA, by request from the pesticide registrant, or sometimes through a court order. If a pesticide registration is cancelled, the EPA will publish a Notice of Intent to Cancel (NOIC) in the Federal Register. The NOIC will usually outline what should be done with existing stocks of the pesticide. Anyone who is negatively affected by the pesticide cancellation can request a hearing on the EPA’s decision. If a hearing is held, any decision issued in regard to the pesticide is final and unreviewable.

Federal Food, Drug, and Cosmetic Act

The portions of the FFDCA that affect pesticides guide the establishment of tolerances for pesticides and their residues in food and feed. Foods that have residue amounts higher than allowable tolerances or where no tolerance has been specified are deemed to be adulterated and cannot be sold.

The tolerance level of pesticides and their residues in foods or feeds must be “safe.” The standard for “safe” requires that there be “a reasonable certainty of no harm.” This standard must be determined based on all potential exposure to individuals over their lifetimes, and special care is given to protect infants and children. Higher tolerances are allowed in only limited instances when greater harm to the public would occur from not using a pesticide. The higher tolerances are required to be “safe” for infants and children, not greater than 10 times more likely to cause cancer, and not more than twice the risk of a “safe” level over a lifetime. FFDCA preempts state pesticide tolerances and only permits lower tolerances in states that receive EPA approval based on special circumstances. Periodic review of established tolerances is required on a five-year cycle.

The Food and Drug Administration and the USDA monitor and enforce the tolerances established by the EPA. EPA actions under FIFRA and FFDCA are coordinated. If a tolerance is revoked, the corresponding pesticide will have its uses on food canceled.

Worker Protection Standards (WPS)

EPA’s Agricultural Worker Protection Standard (WPS) aims to reduce pesticide poisonings and injuries among agricultural workers and pesticide handlers. In 2015, EPA revised the WPS in an effort to decrease pesticide exposure incidents among farmworkers and their family members.

The goal of the WPS is to protect specific types of agricultural employees from occupational exposure to pesticides. To accomplish that, WPS focuses on “pesticide handlers,” employees who mix, load, or apply agricultural pesticides; clean or repair pesticide application equipment; or assist with the application of pesticides. Additionally, WPS provides protections for agricultural workers who may be exposed to pesticides in the course of their work. This includes individuals who perform tasks related to growing and harvesting plants on farms or in greenhouses, nurseries, or forests, including carrying nursery stock, repotting plants, watering, or other tasks directly related to the production of agricultural plants.  Further, some WPS requirements specifically apply to anyone doing certain tasks, such as handling pesticide application equipment or cleaning or laundering pesticide-contaminated personal protective equipment.

Generally, employers at facilities that use, or store pesticides are responsible for WPS compliance.  Some examples include employers on agricultural establishments that grow and harvest fruits and vegetables, employers in forests or at nurseries that produce timber or grow trees, and employers at greenhouses and nurseries who grow plants. No matter what the function of the workplace is, all employers who are responsible for WPS compliance are subject to numerous requirements which include providing access to specific information, decontamination supplies, safety trainings, and emergency transportation in the event of a pesticide related injury.  However, some types of employers are subject to additional requirements under WPS. For example, WPS requires those who employ pesticide handlers to monitor their handlers, ensure equipment safety and provide Personal Protective Equipment (PPE) that is in clean and good operating condition. Although WPS applies to a wide variety of employers, WPS also provides for a number of exceptions to those requirements. For example, owners and immediate family members on family-owned farms are exempt from many of the WPS requirements and there are a number of exceptions for Certified or licensed crop supervisors. Finally, there are other exceptions for a limited number of more specific circumstances.

Additional Statutes

Many other statutes impact pesticides. The Endangered Species Act (ESA) prohibits actions that negatively impact endangered species and their habitat. Under this statute, the EPA must ensure that its pesticide registrations do not threaten endangered species or their habitat. For more information on the ESA, please visit our Endangered Species Act Reading Room.

The Safe Drinking Water Act provides for the protection of the nation’s drinking water. The development of standards and testing for pesticides and other chemicals in the water supply is required under the Act.

The Clean Water Act (CWA) regulates the discharge of pollutants into the waters of the United States. In certain instances, pesticides may be deemed to be pollutants. Although some conflicting case law exists, the EPA has interpreted the CWA to mean that pesticides properly applied to surface waters according to all FIFRA requirements and label directions are not pollutants under the CWA and do not require a permit. A pesticide application onto a water protected by the CWA that did not follow all FIFRA requirements or label directions would be a pollutant and could result in violations of both FIFRA and the CWA. For more information on the Clean Water Act, please visit our Clean Water Act Reading Room.

For information concerning pesticides and their relationship to agricultural labor, please see the Labor Reading Room. For more information on FIFRA and other environmental statutes, please see the Environmental Law Reading Room.

Recent Updates

In June 2026, the United States Supreme Court issued its ruling in Monsanto Co. v. Durnell, No. 21-1068 (2026), a case concerning the scope of FIFRA preemption of state authority to regulate pesticides. In that decision, the Court held that FIFRA preempts state law civil tort duties, such as those raised by failure-to-warn, if those duties would require a pesticide manufacturer to include language on a pesticide label that is “in addition to” or “different from” the EPA-approved label. For more information on this decision, click here.

In April 2025, the EPA published a final draft of its Insecticide Strategy. This strategy marks the most recent effort by the EPA to revise how the agency upholds its ESA responsibilities when taking actions under the FIFRA. This strategy works to reduce pesticide exposure to protected wildlife through mitigation measures intended to curb pesticide spray drift and runoff. This Strategy will not be self-implementing. As new pesticide products get approved, producers can expect to begin seeing mitigation measures appearing on pesticide labels. However, full implementation is likely not to occur for some time. The year before, EPA released its final Herbicide Strategy which is nearly identical to the Insecticide Strategy but focuses on reducing spray drift and runoff from herbicides rather than insecticides in order to reduce exposure to listed species.

In August 2024, the EPA enacted the first pesticide ban in several decades. Dacthal, or dimethyl tetrachloroterephthalate, is used as an herbicide to kill weeds and has been in use since the late 1950s. In 1995, EPA labeled this chemical as a potential carcinogen in 1995, and EPA based its’ current decision on scientific evidence that the pesticide was harmful to reproductive and fetal health.