Pesticide Exposure: Routes, Symptoms and How to Reduce It

Pesticide exposure is contact between the body and chemicals that kill or control pests. It happens mainly through the skin, mouth and lungs, and the eyes add a fourth entry point. Health effects range from acute poisoning to chronic organ damage. Applicators, pest control workers and youth working in agriculture face the most risk. Most acute effects last about 48 hours after spraying. Reducing exposure takes five steps, and first aid starts with leaving the area and moving into fresh air. Urine samples and blood tests measure exposure, and standards include state certification for restricted-use pesticides.

What Is Pesticide Exposure?

Pesticide exposure is contact between the body and chemicals that kill or control pests. Those pests include insects, rodents, bacteria and fungi. Pesticides are inherently toxic, and each product pairs an active ingredient with inert carrier ingredients that can cause health problems. Contact happens in agriculture, forestry, professional and domestic pest control, treated wood, sheep dip, parks and food residues. Pesticides enter the body through the skin, mouth, lungs and eyes. A single acute episode differs from repeated low-level contact. Chronic poisoning shows symptoms only after weeks, months or even years. Chronic problems include chronic obstructive pulmonary disease and cancer. A 2006 study by Linda A McCauley found clear links to health effects only for acute exposure. The United States Environmental Protection Agency registers pesticides for use. It requires manufacturers to print on the label when and how to use each product. Chlorpyrifos, an organophosphate insecticide, shows the scope because it controls foliage and soil-borne insect pests. Aldicarb became a restricted use pesticide in 1981 and went under Special Review in 1984.

What Are the Routes of Pesticide Exposure?

Pesticide exposure occurs mainly through dermal, oral and respiratory routes, and the eyes add a fourth entry point. Pesticides reach the body fastest through the skin, because dermal contact is the most common and effective route. Key routes include:

• Skin (dermal): Skin contact is the most common and effective route of pesticide exposure. Splashing, spillage and spray drift put the chemical on the skin.
• Inhalation (lungs): Inhalation moves airborne pesticide into the lungs. Chloropicrin, a soil fumigant, led California to set buffer zones for workers, neighbors and passersby.
• Ingestion (mouth): Ingestion delivers pesticide through the gastrointestinal tract. After accidental swallowing or touching, the Illinois Poison Center advises a call to 1-800-222-1222.
• Eyes: Eye contact is a separate entry point. The advised response is rinsing with water for 10 to 15 minutes, with contact lenses removed first.

A 1991 study by D H Branson on protective clothing shows that clothing acts as a barrier. Personal protective equipment is fundamental for the safety of workers. Malathion shows the public health context, since this organophosphate controls mosquito-borne illnesses. The Pesticide Handlers Exposure Database supplies the generic unit exposures behind agency exposure assessments. The National Institute for Occupational Safety and Health is the federal agency that researches work-related injury and illness.

How Does Skin Contact Lead to Pesticide Exposure?

Skin contact leads to pesticide exposure when pesticide residues cling to skin and clothing. The residues then pass through the skin into the body. Pesticide residues are often invisible and stay on skin, clothing, hats, boots, tools, lunch coolers and car seats. Cutaneous lesions greatly increase the percentage dose of pesticide that the skin absorbs. Clothing acts as a dermal barrier, as the 1991 Reviews of environmental contamination and toxicology paper by Branson explains. The Agricultural Health Study follows licensed pesticide applicators and their spouses from Iowa and North Carolina. A growing body of evidence links occupational pesticide exposure to pathologies from eczema to neurological diseases and cancer. Washing hands and changing clothes right after using insecticides cuts further contact. Workers remove and wash clothing when finished, apart from regular family laundry. Permethrin effects on human health depend on how much of the chemical reaches the body.

How Does Inhalation Lead to Pesticide Exposure?

Inhalation leads to pesticide exposure when airborne droplets, vapor or dust carry pesticides into the lungs. Pesticide drift spreads this airborne material, and rural residents next door to farms meet it. Outdoor spraying poses the obvious risk, but inhalation exposure occurs indoors as well. Measurable levels of up to a dozen pesticides appear in the air inside homes. An inhaled pesticide calls for moving the person to fresh air right away and loosening tight clothing. Chloropicrin is regulated by the United States Environmental Protection Agency as a restricted use pesticide. Glyphosate reaches the air through aerial sprays and ground broadcast sprayers. The Total Exposure Assessment Methodology study measured personal exposures in the air, drinking water and breath of 400 residents. A 2022 workshop report by Martin Röösli shows that evidence on exposure interventions stays limited. Understanding of the concentrations that produce effects remains insufficient at present.

What Are the Health Effects of Pesticide Exposure?

Pesticide exposure causes health effects that range from acute poisoning to chronic organ damage. The effects depend on the pesticide and the dose. The main effects are:

• Acute poisoning: Acute poisoning is harm that follows one episode of ingestion, inhalation or skin contact. Its effects appear shortly after exposure or within 48 hours, unlike chronic poisoning, which stays silent for weeks or years.
• Organophosphate and carbamate symptoms: These symptoms follow inhibition of acetylcholinesterase. They include difficulty breathing, confusion, runny nose, sweating, salivation, stomach cramps, dizziness, chest tightness, nausea and muscle twitching or weakness.
• Chronic organ damage and cancer: Chronic exposure to some pesticides damages the liver, kidneys, endocrine system and nervous system. Cancer can follow repeated low-level exposure.
• Delayed nerve effects: Intermediate syndrome develops 1 to 3 days after organophosphate exposure despite treatment. Organophosphate-induced delayed neuropathy brings paresthesias, ataxia and paralysis. Some organophosphates, such as chlorpyrifos, cause an axonal neuropathy that begins 1 to 3 weeks after exposure.

Intermediate syndrome may lead to respiratory paralysis and death. A 2007 study by Ashish Goel in The National medical journal of India reports this. A 2014 systematic review by S Karami-Mohajeri examined nerve conduction testing for diagnosing organophosphorus exposure. Diagnosis stays clinical and sometimes relies on a trial of atropine. Atropine is an anticholinergic medication that treats some pesticide poisonings. The Agency for Toxic Substances and Disease Registry protects communities from harmful effects of hazardous substances.

Can Pesticide Exposure Cause Cancer?

It depends. Carcinogenic pesticides cause cancer, and pesticide exposure raises the risk with the dose and duration. Glyphosate shows this, because a 2019 study by Luoping Zhang found a 41% rise in non-Hodgkin lymphoma risk. That meta-analysis covered glyphosate-based herbicide exposure in the highest exposure groups. The International Agency for Research on Cancer classified glyphosate as probably carcinogenic to humans. A study by Zhen Liang published in Oncotarget in 2016 linked pesticide exposure to an increased risk of bladder cancer. Single exposure events rarely cause cancer, but repeated contact does, even at very low doses. Paradichlorobenzene causes cancer in animals, yet substantial scientific uncertainty exists over long-term human exposure. The Agricultural Health Study began in 1993 to learn how farming, lifestyle and genes shape health.

Is Pesticide Exposure Linked to Parkinson’s Disease?

It depends. Pesticide exposure is linked to Parkinson’s disease for some pesticides, and paraquat shows the clearest link. Parkinson’s disease is a condition that James Parkinson described in 1817, marked by progressive tremors, rigidity and akinesia. A 2019 meta-analysis by Wimonchat Tangamornsuksan showed an association between the disease and paraquat exposure. Parkinson’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis seem the diseases most tied to pesticide neurotoxicity. Studies demonstrate adverse effects on the nervous system at low pesticide doses. Adolescent applicators had poorer short-term memory and attention than non-applicators. They carried higher biomarkers of exposure. Rotenone may act as a developmental neurotoxicant in brain cell cultures. The evidence does not show a consistent link for every pesticide.

Who Is Most at Risk From Pesticide Exposure?

Pesticide applicators, pest control workers and youth working in agriculture face the most risk from pesticide exposure. Farmworkers and farm workers face it too, as do household members of farmworkers. Agricultural workers form a potentially vulnerable population, as a 2020 study by Cynthia L Curl from Boise State University reports. Farmers meet pesticides while treating crops, plants and grain stores. Pest control workers treat buildings, forests and wood. Youth in agriculture face hazards that can harm the developing adolescent brain. Exposure to synthetic pesticides may be associated with adverse health outcomes. A paper by Linda A McCauley in Environmental health perspectives found clear linkages only for acute pesticide exposure. The World Health Organization assesses the risks to humans from pesticides. Pesticide Action Network is a coalition of more than 600 groups in 90 countries. NIOSH created the SENSOR-Pesticides Program to reduce occupational injuries and illnesses.

How Can Children and Household Members Be Exposed?

Children and household members are exposed to pesticides when farmworkers carry residues from the field into the home. Residues travel on skin, clothes, boots and containers, so family members meet them in farmworker housing near fields. Direct household pesticide application adds a second route. A United States analysis of all reported pesticide poisonings showed that 57% involved children under the age of 6 years. In households with children under five, almost one-half stored a pesticide product within reach. The pesticide take-home pathway study among children of agricultural workers describes this route. A 2006 paper by McCauley studies health outcomes in farmworker populations exposed to pesticides. Keeping children and pets away from insecticides lowers contact. Unneeded pesticides stay out of the home, and unwanted containers go to safe disposal. Paraquat moved into beverage containers has been swallowed by mistake. Glyphosate residues in food showed no risks of concern for infants and children in the 2017 assessment.

How Long Does Pesticide Exposure Last After Spraying?

Pesticide exposure after spraying lasts about 48 hours for most acute effects. Organophosphates that do not inactivate cholinesterase are metabolized and excreted, mostly within 24 to 48 hours. Carbamates clear spontaneously within approximately 48 hours after exposure. Blood cholinesterase regenerates in about 120 days after organophosphate poisoning when no further exposure occurs. It recovers faster after carbamate poisoning. Weakness of proximal, cranial and respiratory muscles develops 1 to 3 days after organophosphate exposure. Signs that start more than 12 hours after exposure probably have another cause. Pesticides can be found far from the site of spraying. People stay away from sprayed areas until the area is dry. The Restricted Entry Interval protects workers who enter treated areas. Diagnosis of a late effect is clinical and sometimes relies on a trial of atropine. A 2014 systematic review by S Karami-Mohajeri from Tehran University of Medical Sciences describes nerve testing for late effects.

Is Indoor Pesticide Exposure Higher Than Outdoor?

Yes. Indoor pesticide exposure is higher than outdoor exposure. One study suggests that 80% of most people’s exposure to pesticides occurs indoors. In the past year, 75% of US households used at least one pesticide product indoors. Products that kill household pests include insecticides, termiticides and disinfectants. Outdoor products never belong inside. Understanding of indoor pesticide concentrations remains insufficient at present. The amount of pesticide found in homes is greater than recent use explains. Contaminated soil or dust tracked inside is one possible source. Chlorpyrifos has served as a pesticide since 1965 in agricultural and non-agricultural areas. A 2020 study by Cynthia L Curl cautions that exposure to synthetic pesticides may be associated with adverse health outcomes.

Does a Pesticide Smell Mean Exposure Is Still Happening?

It depends. Pesticide odor does not prove that exposure is still happening, since smell does not measure dose. An odor alone cannot show whether exposure continues. Ventilating the area well after pesticide use removes odors. Clean, dry and well ventilated indoor spaces avoid pest and odor problems. Integrated Pest Management is a series of pest management evaluations, decisions and controls. NIOSH determines recommended exposure limits for toxic chemicals. Permethrin effects depend on the length and frequency of exposure. Angelina Duggan in Regulatory toxicology and pharmacology shows that urinary metabolite biomonitoring measures exposure better than smell.

How Can You Reduce Pesticide Exposure?

To reduce pesticide exposure, follow the 5 steps below. You cut exposure when pesticide labels, protective clothing and safe storage block each route of contact. The Swiss Tropical and Public Health Institute workshop report by Martin Röösli found limited evidence on which interventions work.

1. Use pesticides strictly according to the manufacturer directions, since the label sets when and how to apply the product. Never apply insecticides outside on a windy day.
2. Wear protective clothing, including gloves, goggles, long sleeves and long pants, because clothing acts as a dermal barrier, as a study by D H Branson from Oklahoma State University shows.
3. Increase ventilation and move plants and pets outdoors when applying indoors, which keeps inhaled residues low.
4. Remove and wash clothing when finished, separately from family laundry, so residues stay off the family.
5. Store only needed pesticides and dispose of unwanted containers safely, which keeps them away from children.

Integrated Pest Management is the approach that EPA recommends, and it minimizes the use of chemical pesticides. The approach applies to the home, garden and workplace. EPA and Bayer CropScience agreed to end aldicarb use in the United States.

What First Aid Is Needed After Pesticide Exposure?

To give first aid after pesticide exposure, start with leaving the area and moving into fresh air. Move the exposed person to fresh air right away and loosen tight clothing. Remove contaminated clothing or jewelry. Wash affected areas with soap and water. Call 911 if the person is unconscious or has difficulty breathing. Call the Poison Center for advice on what to do and what to watch for after any pesticide exposure. Expect clinical management of proper oxygenation, atropine in escalating doses and pralidoxime in high doses. A 2007 study by Ashish Goel from the All India Institute of Medical Sciences reports this. Know that intermediate syndrome can develop and may lead to respiratory paralysis and death. Note that diagnosis is clinical and sometimes relies on a trial of atropine. Acute exposure to organophosphates can lead to death through respiratory depression. Rinse skin and eyes quickly after paraquat contact to prevent severe injury.

How Is Pesticide Exposure Measured?

To see how pesticide exposure is measured, start with urine samples and blood tests. Urinary metabolites show organophosphate exposure, and researchers test blood and urine for evidence of pesticides. Collect urine samples within one or two days after pesticide application to coincide with maximum metabolite excretion. Compare urinary metabolite levels of adults and children in farmworker households with national reference data. Study biomonitoring of six alkyl phosphate metabolites of organophosphates. A 2003 study by Angelina Duggan in Regulatory toxicology and pharmacology describes it. Expect household variability, since factors such as a non-nuclear family structure change exposure. Check the law, which requires evaluation of both aggregate and cumulative health risks from pesticides. The Pesticide Data Program is a national pesticide residue monitoring program. The Biomarkers of Exposure and Effect in Agriculture study collected biospecimens from over 1,600 farmers and pesticide applicators. The California Department of Pesticide Regulation maintains a comprehensive list of references.

Which Standards Limit Pesticide Exposure?

Pesticide exposure standards include state certification for restricted-use pesticides, warning labels on paradichlorobenzene products and IPM as the recommended approach. Label directions and cancelled cyclodiene uses limit pesticide exposure too. Use inconsistent with a label is illegal under the Federal Insecticide, Fungicide, and Rodenticide Act. State certification covers restricted use pesticides. Unless trained and certified, people never use a pesticide restricted to state-certified pest control operators. The Worker Protection Standard protects farm employees. No further sale or commercial use is permitted for chlordane, aldrin, dieldrin and heptachlor. Heptachlor keeps one exception for fire ants in underground cable boxes. EPA requires that paradichlorobenzene products bear warnings such as avoid breathing vapors. No air concentration standards for pesticides have been set. A 2003 study by Angelina Duggan notes that the law requires cumulative risk evaluation. The Joint Meeting on Pesticide Residues harmonizes risk assessment of pesticide residues. The European Food Safety Authority reviewed the maximum glyphosate levels permitted in food. The World Health Organization and FAO developed the International Code of Conduct on Pesticide Management. EPA denied a petition to revoke all chlorpyrifos tolerances in March 2017.