What are pesticides?
Pesticides are substances that prevent, destroy, repel, or reduce the severity of pests. Pests are living things that occur where they are not wanted or that cause damage to humans, crops, or animals. Pests can be insects, mice, unwanted plants such as weeds, bacteria, viruses, or different types of fungus.
Pesticides include algicides, which control algae in swimming pools and other bodies of water; antifouling agents, which kill organisms attached to boat bottoms; fungicides, which kill fungi such as mildew, mold, and rust; herbicides, which kill weeds; insecticides, which kill insects; and rodenticides, which control mice and other rodents.
The U.S. Environmental Protection Agency (EPA) grants licenses, or registrations, to pesticides that it has found do not pose unreasonable risks to human health and the environment; it has registered at least 865 pesticides, which are used in thousands of pesticide products.
Household products that are pesticides include cockroach baits and traps, insect repellants, rat and mouse poison, flea and tick sprays and collars for pets, disinfectants, products that kill mold and mildew, weed killers, bug and mosquito sprays, and some swimming pool chemicals.
Some pesticides are persistent organic pollutants (POPs). Some pesticides are made with ammonia, arsenic, benzene, chlorine, dioxins, ethylene oxide, formaldehyde, and methanol. Polychlorinated biphenyls (PCBs) had been used to make pesticides before they were banned.How might I be exposed to pesticides?
Pesticides are common chemicals found in thousands of household and industrial products. You can be exposed to pesticides by inhaling them or absorbing them through your skin. You can also be exposed by eating food that has been treated with pesticides or drinking water that has been contaminated with pesticides.
You can be exposed to pesticides if you use pesticide products in your home, office, yard, or boat. You can be exposed at home if you use a professional service that uses pesticides, such as a pest control service, lawn maintenance service, or swimming pool maintenance service.
You can be exposed to pesticides at work if you work on a farm or outdoor facility that uses herbicides or insecticides. You can be exposed if you work at a facility that manufactures pesticides or if your office or facility uses a professional pest control service. You can be exposed if you work at a pest control service, lawn maintenance service, swimming pool maintenance service, or boat-cleaning operation.
Pesticides can vary in how toxic they are to humans and the environment. Some are persistent in the environment, animals, and birds, lasting for years; others break down soon after they are released.
Different types of pesticides can affect your health in different ways. Some pesticides are carcinogens, known to cause cancer. Some can cause birth defects. Some affect the nervous system. Some pesticides are endocrine disruptors and affect the body's hormones and endocrine system. Some may irritate the skin and eyes.
The amount of a pesticide you are exposed to is as important as how toxic the pesticide is. A low level exposure to a highly toxic pesticide may pose the same amount of danger as a high level of exposure to a less toxic pesticide.
Infants and children may be especially sensitive to the health risks of pesticides because their internal organs are still developing. In relation to their body weight, they also are exposed to more pesticides in food and water than adults.
Pesticides may harm a developing child by blocking the absorption of important food nutrients necessary for normal healthy growth. There are also critical times in early human development when exposure to a pesticide can permanently alter the way a child's biological system operates.
If you think you are having symptoms from pesticides, contact your health care professional.
For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.
This description is based on the information found in the Web links listed with this topic.
Web Links from MedlinePlus (National Library of Medicine)
Childhood Pesticide Poisoning (World Health Organization) (PDF — 652 KB)
Ingredients Used in Pesticide Products (Environmental Protection Agency)
Map of Superfund Hazardous Waste Sites with Pesticides in the United States. TOXMAP (National Library of Medicine)
National Pesticide Information Center (Environmental Protection Agency, Oregon State University)
Pesticide Exposure. Enviro-Health Links (National Library of Medicine)
Pesticides (National Institute of Environmental Health Sciences)
Pesticides home page (Environmental Protection Agency)
Pesticides in the Nation's Streams and Ground Water 1992 - 2001: A Summary (US Geological Survey)
Pesticides Matter (Program on Reproductive Health and the Environment, University of California San Francisco) (PDF — 1.14 MB)
Pesticides. Haz-Map (National Library of Medicine)
Pesticides. Household Products Database (National Library of Medicine)
Preventing Health Risks from the Use of Pesticides in Agriculture (World Health Organization) (PDF — 569 KB)
Last Updated: June 27, 2016