Pesticides

The EPA defines pesticide as any substance or mixture of substances intended for preventing, destroying, repelling, or mitigating any pest.  Pests can be insects, mice and other animals, unwanted plants (weeds), fungi, or microorganisms like bacteria and viruses.  The term pesticides not only refers to insecticides, but also applies to herbicides, fungicides, and various other substances used to control pests.  A pesticide may also be any substance or mixture of substances intended for use as a plant regulator, defoliant, or desiccant.

Most pesticides pose some risk of harm to humans, animals, or the environment because they are designed to kill or otherwise adversely affect living organisms.  The Office of Pesticide Programs of the Environmental Protection Agency is chiefly responsible for regulating pesticides.  The EPA also regulates devices used to control pests.  A “device” is any instrument or contrivance (other than a firearm) intended for trapping, destroying, repelling, or mitigating any pest.  These devices are subject to certain labeling, packaging, record keeping, and import/export requirements.

The EPA excludes certain categories from the definition of pesticides.  They are drugs used to control diseases of humans or animals; fertilizers, nutrients, and other substances used to promote plant survival and health; biological control agents, except for certain microorganisms, are exempted from regulation by EPA. The EPA has also exempted certain other low-risk substances, such as cedar chips, garlic, and mint oil from the definition of pesticides.

Pesticides may be chemical or biological.  Most of the chemical pesticides affect the nervous system by disrupting an enzyme that regulates acetylcholine, a neurotransmitter.

Before marketing and using a pesticide in the United States, the EPA evaluates the proposed pesticide thoroughly to ensure that it will not harm human health or the environment.  Pesticides that pass this evaluation are granted a license or “registration.”  Such registration permits their sale and use according to requirements set by the EPA to protect human health and the environment.

Through pesticide registration, the EPA examines the ingredients of a pesticide; the site or crop on which it is to be used; the amount, frequency and timing of its use; and storage and disposal practices. The EPA ensures that the pesticides will not have any unreasonable adverse effects on humans, the environment and non-target species.  Pesticides must be registered or exempted by EPA’s Office of Pesticide Programs before they may be sold or distributed in the U.S.  Once registered, a pesticide may not legally be used unless the use is consistent with the approved directions for use on the pesticide’s label or labeling.

The EPA may determine in certain situations that some additional data is required to support an existing registration of a pesticide.  If the applicant does not provide the necessary data within the specified time, or does not comply with the EPA instructions, the EPA will suspend the pesticide.

After a pesticide is registered by the EPA, states can register pesticides under specific state pesticide registration laws.  A state may have more stringent requirements for registering pesticides for use in that state.  Ultimately, states have primary responsibility (called primacy) for pesticides used within state borders.

Before allowing the use of a pesticide on food crops, the EPA sets a tolerance, or maximum residue limit, which is the amount of pesticide residue allowed to remain in or on each treated food commodity.  If residues are found above the tolerance level, the commodity will be subject to seizure by the government.

In setting the tolerance, the EPA makes a safety finding as to whether the pesticide can be used with “reasonable certainty of no harm.”  For this, the EPA considers the toxicity of the pesticide and its break-down products, how much of the pesticide is applied and how often, and how much of the pesticide remains in or on food by the time it is marketed and prepared.  This tolerance applies to food imported into the U.S., as well as to food grown in the U.S.

The EPA’s pesticide tolerances for food are enforced by several government agencies.  The federal Food and Drug Administration (FDA) tests food produced in the United States and food imported from other countries for compliance with these residue limits.  State enforcement agencies also check foods produced in U.S.  The U.S. Department of Agriculture tests meat and milk.  USDA and FDA have programs designed to develop statistically valid information on pesticide residues in foods that they provide to the EPA for use in its risk assessment for pesticides.  Whenever the USDA staff detects violations of tolerances in their data collection program the FDA is notified.

The EPA’s civil enforcement program is designed to conduct investigations and bring cases to address the most significant violations on the matter.  Civil enforcement includes EPA administrative actions and judicial cases referred to the Department of Justice.  The EPA works closely with states as well as tribes and federal agencies to implement federal programs.  The EPA also provides information on civil enforcement related to enforcement programs and federal facilities enforcement.


Inside Pesticides