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Pesticides - Health Effects

What kinds of health effects are associated with pesticides? Pesticides are designed to kill “pests”, but some pesticides can also cause health effects in people.

What kinds of health effects are associated with pesticides?

Pesticides are designed to kill “pests”, but some pesticides can also cause health effects in people. The likelihood of developing health effects depends on the type of pesticide and other chemicals that are in the product you are using, as well as the amount you are exposed to and how long or often you are exposed. Most often, pesticides affect the nervous system (system in your body that controls your nerves and muscles). General health effects from acute (short-term) exposures or poisonings are listed in the table below. NOTE: The term “pesticide” describes a very large and diverse group of chemicals or products. It is very important to always get specific information about the exact product you are using. Some health effects from pesticide exposure may occur right away, as you are being exposed. Some symptoms may occur several hours after exposure. Other effects may not be noticed for years, for example cancer. Some symptoms of pesticide exposure will go away as soon as the exposure stops. Others may take some time to go away. For people exposed to pesticides on a regular basis, long-term health effects are a concern. Women who are pregnant or breast-feeding should check with their doctors before working with pesticides as some pesticides may be harmful to the fetus (unborn baby) or to breast-fed infants. Certified pesticide applicators or people who work with pesticides are encouraged to have regular medical check-ups. Tell your doctor which pesticides you are working with and/or exposed to.

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chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: irritation of the nose, throat, eyes or skin
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: headache
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: dizziness
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: loss of appetite
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: thirst
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: nausea
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: diarrhea
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: sweating
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: weakness or fatigue
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: restlessness
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: nervousness
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: changes in mood
chemical TableGeneral Symptoms that Might Indicate Pesticide Poisoning: insomnia
general vomiting
general excessive salivation
general coughing
general feeling of constriction in throat and chest
general abdominal cramps
general blurring of vision
general rapid pulse
general excessive perspiration
general profound weakness
general trembling
general muscular incoordination
general mental confusion
general inability to breathe
general extra phlegm or mucous in the airways
general small or pinpoint pupils
chemical chemical burns on the skin
general increased rate of breathing
general loss of reflexes
general uncontrollable muscular twitching
general unconsciousness
general death

How do pesticides enter our bodies?

Pesticides can enter your body during mixing, applying, or clean-up operations. There are generally three ways a chemical or material can enter the body:

context through the skin (dermal),
context through the lungs (inhalation), or
context by mouth (ingestion).

Dermal (absorption through skin or eyes)

context In most work situations, absorption through the skin is the most common route of pesticide exposure. Absorption continues as long as the pesticides remain in contact with the skin. People can be exposed to a splash or mist when mixing, loading or applying the pesticide. Skin contact can also occur when you touch a piece of equipment, protective clothing, or a surface that has pesticide residue on it.
context Pesticides can also be absorbed through your eyes. In addition, pesticides, can cause injuries to the eye itself.

Inhalation (through the lungs)

context Inhalation may occur when working near powders, airborne droplets (mists) or vapours. The hazard from low-pressure applications is fairly low because most of the droplets are too large to remain in the air. Applying a pesticide with high pressure, ultra-low volume, or fogging equipment can increase the hazard because the droplets are smaller and they can be carried in the air for considerable distances. Pesticides with a high inhalation hazard will be labelled with directions to use a respirator. Pesticides can be absorbed easily through lung tissues.

Ingestion (by mouth)

context While ingestion (by mouth) is a less common way to be exposed, it can result in the most severe poisonings. There are numerous reports of people accidentally drinking a pesticide that has been put into an unlabelled bottle, beverage cup or container (including soft drink cans or bottles). Workers who handle pesticides may also unintentionally ingest the substance when eating or smoking if they have not washed their hands first.
context (From: British Columbia Ministry of Agriculture, 2022. “Pesticide Toxicity and Hazard”)
context For more information about how chemicals can enter your body, please see the OSH Answers document How Workplace Chemicals Enter the Body.

How do I know if a pesticide will be harmful to me?

Because there are so many types of pesticides, the toxicity can vary greatly. The likelihood of becoming ill from exposure to pesticides depends on a number of factors including: In general, the risk of illness increases as the concentration (strength) of the pesticide, and duration (length) of exposure increases. "How much" and "how long" is necessary to cause illness will depend on the exact type of pesticide. For more information about routes of exposure, and types of toxicity, please see the OSH Answers document What Makes Chemicals Poisonous?.

context the type of pesticide (some pesticides are more harmful than others),
context the amount of pesticide you were exposed to (how much),
context the concentration/strength (how strong/dose),
context the length of exposure or duration (how long/time),
context “route of entry” into the body (skin, ingestion, or inhalation), and
context other carriers or chemicals in the pesticide product.

Can people become allergic to pesticides?

context In some cases, yes. There are two types of allergic sensitization: skin and respiratory. Symptoms of skin sensitization may include swelling, redness, itching, pain, and blistering. Respiratory sensitization symptoms may include wheezing, difficulty in breathing, chest tightness, coughing and shortness of breath. In some cases, respiratory sensitization can produce a severe asthma attack.
context As the allergy develops, the reaction can become worse with each exposure. Eventually, even a short exposure to a low concentration of the pesticide can cause a very severe reaction. Although it is rare, it is important to be aware that pesticides may have the ability to cause life threatening allergic reactions in some people.

Can pesticides cause cancer?

Health Canada recommends buying pesticides that use a Pesticide Control Products (PCP) number on the label. Products using a PCP number have been approved by Health Canada. Before a pesticide is allowed to be used or sold in Canada, it must undergo a rigorous scientific assessment process to ensure that no harm will occur when pesticides are used according to label directions. It is also assessed to determine if it is effective for its stated purpose. All pesticides registered in Canada, including for agricultural, forestry and domestic uses, undergo this level of scrutiny. There are many different ingredients used in pesticide formulations. As with all chemical exposures, it is “good practice” to use products as little as possible (or not at all) or to use a less toxic substance. If you must use a pesticide, always follow the safe use, handling and storage directions.