Pesticides repel or kill unwanted pests such as insects (insecticides), rodents (rodenticides), fungi (fungicides), and weeds (herbicides). All pesticides have the potential to be toxic to humans. Pesticides sold in the United States must be registered with the Environmental Protection Agency (EPA).
How are we exposed to pesticides?
We come into contact with pesticides through plants, soil, air, and food. Outdoor pesticides are tracked into our homes on shoes, strollers, and the bodies of children who run and play in pesticide-treated areas. How a pesticide is applied can greatly affect the risk of exposure to people during and after application.
- Sprays: Aerosol sprays may be directly applied to a target or more broadly distributed using a “fogger” or “bomb.” All of these products increase the risk of inhalation exposure. The use of foggers and bombs is not recommended as they can be particularly dangerous. Exposures via the skin can also occur from direct contact with sprayed surfaces. Spraying is almost always associated with pesticide drift, the dispersal of pesticides in the air beyond the target site. This means that what your neighbors apply to their lawn will likely add to your family’s pesticide exposure.
- Granular pesticides are typically applied to the soil surface to target pre-emergent weeds or sprinkled around areas of pest infestations. Exposure to these products is most likely via ingestion or through the skin.
- Stationary bait traps contain pesticides in a solid or granular form. These traps should always be kept out of reach of children and pets to avoid accidental ingestion and contact.
Who is most at risk?
- Children are at highest risk for exposure due to their proximity to the ground where pesticides settle and their age-appropriate hand-to-mouth behaviors. Their higher breathing rates also increase risk of exposure compared with adults.
- Fetuses: Pregnancy is one of the most vulnerable windows for exposure to pesticides. Studies show that exposures in-utero are associated with cognitive, behavioral, and respiratory problems during childhood and beyond.
- Agricultural workers and their families as well as individuals living in agricultural areas experience higher exposures than the general public. Farming communities have higher rates of certain cancers including leukemia, non-Hodgkin’s leukemia and lymphoma, soft tissue sarcoma, and skin, lip, stomach, brain, and prostate cancers.
Children are at highest risk for exposure due to their proximity to the ground where pesticides settle and their age-appropriate hand-to-mouth behaviors. Their higher breathing rates also increase risk of exposure compared with adults.
What are the health effects of pesticides?
Health risks differ depending on the chemicals in a product and whether the exposure is acute (brief, typically high dose) or chronic (occurring over a long period of time, typically low dose). Acute exposures are most common in agricultural workers or poisonings. Chronic exposures to low doses of pesticides are more common due to consumer practices and household use.
- Nervous System Effects: Many classes of pesticides exert their effects by damaging the nervous system of a pest. Due to similarities across species, these pesticides have also been shown to be toxic to the nervous system of humans.
- Hormonal System Effects: Several pesticides are classified as Endocrine Disrupting Chemicals (EDCs) due to their potential to interfere with hormones in the body. Disruption of hormonal systems can impair the development and normal functioning of the reproductive system as well as the nervous system, particularly when exposure occurs early in life.
- Inflammatory bowel disease (IBD): A 2024 study identified significant associations between increased risk of IBD and exposure to a mixture of chemicals, notably o-Hydroxybiphenyl, a pesticide. The risk was highest 6–10 years before diagnosis, suggesting a possible critical exposure window or lag period.
- Cancer: Some pesticides have been shown to have the potential to cause cancer in laboratory and animal studies. For instance, glyphosate, the active ingredient in some pesticides is classified as a probable human carcinogen by the World Health Organization.
How can I reduce my exposure to pesticides?
- Practice organic lawn care.
- Utilize integrated pest management (IPM) methods that eliminate or reduce the need for synthetic lawn and garden chemicals.
- Aerate your lawn to allow for healthy root growth.
- Nourish soil with organic compost since nutrient-rich soil reduces pest infestations.
- Choose native plants that thrive in your zone.
- Grow your own organic produce.
- Eliminate standing water that attracts mosquitos.
- Encourage friends and neighbors to reduce the use of pesticides. Pesticides can drift across property lines.
If pesticides must be used
- Never apply pesticides in the presence of children; always avoid areas where they play. Keep children and pets indoors during active spraying.
- Choose the least toxic pesticides. The EPA requires one of three “signal” words on all pesticide labels. In order from least toxic to most toxic, they are: 1) Caution, 2) Warning, 3) Danger.
- Avoid application of pesticides where pesticide run off could enter ponds, streams, drinking water sources, or other bodies of water.
- Hire a licensed professional applicator. If you live in an apartment building, ensure that your landlord is using one.
- Never use a pesticide without an EPA registration number on the label. Unregistered pesticides are sold illegally in the U.S. and may be extremely toxic.
- Target insects at the larval stage using larvicides, which can be more effective and less toxic to humans than spraying mature insects.
- Never use a pesticide in a way other than as instructed on the label. Follow directions closely and utilize recommended personal protective equipment such as gloves, goggles, and face masks.
- Never store pesticides within reach of children.
- Never pour pesticides down the drain. Always dispose of them according to the label directions.
- Never store pesticides in containers other than the ones in which they are sold.
Never use a pesticide without an EPA registration number on the label. Unregistered pesticides are sold illegally in the U.S. and may be extremely toxic.
Pesticide Outreach and Advocacy
Institute scientists play a key role in educating communities and policy makers on the health impacts of pesticide exposures. In 2019 and 2021, we co-hosted the Beyond Pesticides Annual Forum, bringing together speakers with a wide range of expertise including public health, soil science, biodiversity, pediatrics, community activism, and more. Institute scientists are frequently invited by organizations such as the Northeast Organic Farming Association (NOFA), the Sierra Club, and numerous local community groups to participate in panel discussions for lay audiences and to provide educational testimony in support of the reduction of synthetic pesticide use.
Science translation with the goal of supporting safer pesticide practices and policies is a priority for Institute researchers. In 2017, Dr. Sarah Evans joined community advocates to support the elimination of the use of harmful pesticides on New York City public properties, legislation that was finally passed on Earth Day 2021. Read more here and in the New York Times.
At the request of environmental advocacy organizations, Institute scientist Dr. Megan Horton shared with decision makers her research findings demonstrating an association between organophosphate pesticide chlorpyrifos and adverse impacts on children’s brains and behavior, helping to inform the passage of legislation to ban or restrict chlorpyrifos at the federal and state level in NY, Maryland, Oregon, and Minnesota. She co-authored an editorial advocating for a NY state ban on chlorpyrifos for the Buffalo News with Dr. Bruce Lanphear (Simon Fraser University).
In 2023, the Institute for Exposomic Research joined the EcoFriendly Parks for All Coalition to provide training and education to the New York City Parks Department for the implementation of Intro 1524 which banned the use of synthetic pesticides on city-owned properties.
In December 2023, Dr. Maida Galvez joined other health care professionals, farmers and advocates to support proposed state legislation to restrict the use of neonicotinoid pesticides in New York State. The bill was signed into law that month by the Governor.
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