Pesticide Safety

Safe Use of Herbicides, Fungicides and Insecticides

Herbicides, fungicides and insecticides are classified according to the use hazard and risk involved.

The categories of hazard are:

  • toxicity
  • flammability
  • explosive potential
  • corrosivity

The degree of risk is represented by symbols taken from common traffic sign shapes represented by the stop, caution and yield signs. The signal word for each of the signs is danger, warning and caution. Where the risk is minimal, no designation is required. The label on the container will carry the appropriate signs for the protection of the user. Degree of risk information for herbicides, insecticides and fungicides used in fruit crops are summarized in tables entitled "Hazard Ratings and Relative Toxicities" and located just prior to the product descriptions. The symbols are illustrated in Figure 1.

LD50 values are used to rate the toxicity of pesticides. The LD50 refers to the dose of pesticide (in mg per kg of the test animal's body weight) that is lethal to 50 percent of the group of test animals. For example, if a pesticide has a LD50 value of 10 mg/kg, and the test animals each weigh 1kg, then 50 percent of the animals would die if they each ate 10 mg of the pesticide.

Oral LD50 values as they relate to the Risk/Hazard Symbols:

Different types of protective equipment are required for pesticides that differ in toxicity. Special equipment requirements are described on the product label, but in general the following precautions must be taken when using pesticides of different hazard ratings.

Danger Poison - requires goggles, respirator, gloves and skin protection, avoid fumes and spray mist.

Warning Poison - requires goggles, gloves and skin protection, avoid fumes and spray mist.

Caution Poison - requires gloves and skin protection, avoid fumes and spray mist.

The absence of a hazard symbol on a pesticide label indicates low toxicity to mammals. Nevertheless, protective clothing should be worn when using pesticides that do not have a hazard symbol.

Degree of Risk and Hazard Symbols

Protecting Yourself from Exposure

The use of protective equipment and sound safety procedures will help minimize your exposure to herbicides, insecticides and fungicides. Follow the 10 rules for safe application listed, and wear the safety equipment recommended.

10 Rules for Safe Application

  • Never smoke or eat while applying pesticides.
  • Avoid inhaling sprays or dusts. Wear protective clothing and a respirator.
  • Sprayer lines carrying chemicals should not enter the operator's cab.
  • Have soap, water and a towel available. Should concentrated product spill on skin, hands, face or eyes, wash immediately.
  • Wash hands and face when leaving the treated area, before break periods, lunch or urination.
  • Bathe or shower and change to clean clothing after working with pesticides. Wash clothing each day before re-use.
  • Call a physician or get the patient to a hospital immediately if symptoms of illness occur during or shortly after pesticide application. Be sure to take along the product label or container.
  • Store pesticides out of reach of children and where there is no chance of contact with human food or livestock feeds. Do not store herbicides with insecticides and avoid cross-contamination. Storage areas should be locked.
  • Keep chemicals in their original containers, never in unmarked containers or bottles used for food or drink.
  • Follow proper container disposal methods. All containers should be triple rinsed or pressure rinsed, punctured to render the container non-reusable, and delivered to designated disposal sites.

Protective Clothing

Wear protective equipment as described in the chart to reduce exposure.



How to Wear It


There are two types of coveralls: disposable and reusable. Disposable coveralls are lightweight and comfortable on warm days. They can be worn for mixing and applying pesticides, then discarded at the day's end. If they become contaminated, they should be discarded at once.

The second type of coveralls is made of washable fabric and may be reused many times. These fabric coveralls are adequate for use with all but the most highly toxic and concentrated pesticides.

Button (or zip) right up to the neck. Loose coveralls around the neck will suck and blow pesticide in and out of the interior of the coveralls as you bend and move.

Wear coveralls over a long-sleeved shirt and pants.


When pouring or otherwise handling concentrated pesticides, it makes good sense to wear protection in the form of an apron. The apron protects the front of your body from spills or splashes of the concentrate. The apron should be made of rubber or synthetic liquid-proof material that will resist the solvents used in formulating the pesticide.

Make sure the apron covers your body from your chest to your boots.


Protect your hands by wearing appropriate chemical-resistant gloves. Be sure they are designed for use with solvents and pesticides. Refer to the product label for specific recommendations on the type of personal protective equipment required. Never use lined gloves, gloves with wristbands or leather gloves.

Put gloves on and roll up the first inch or two of the cuff. That way when you lift your hands, any liquid on the gloves won't drip down your arm.


Use a chemical-resistant hat, preferably made of washable plastic. The hat may be a hard hat, or it may be made of flexible plastic. In either case, it should have a plastic sweatband. Wash and dry entire hat after each use and before storing. Ordinary baseball caps with cloth sweatband are dangerous as they absorb the pesticide and recontaminate the forehead each time you wear them. Even small amounts of moderately or slightly toxic pesticides may cause severe skin irritation or other illness if exposure continues for several days.


Wear chemical-resistant, unlined boots. These boots are available in a variety of styles and materials. Neoprene boots are the best. Knee-length boots offer greater protection because they extend above the lower end of the apron. Avoid leather or fabric boots and shoes because they will absorb pesticide and cannot be cleaned effectively.

Wear your pant legs outside the top of your boots. This will prevent spills and splashes from running into the boot and on to your leg.

Protecting Your Eyes, Face and Lungs

Wear the following equipment to protect your facial area from exposure.



How to Wear It


Chemical-resistant goggles keep your eyes safe from both splashing and, if using dry formulations, dust or granules. Don't use goggles with cloth or elastic headbands as these will absorb pesticides.

Wear goggles snugly on your face so that the sides of your head are protected from splashes. If you wear glasses, make sure you purchase goggles which fit snugly over them. Never wear contact lenses when working around pesticides.


Only NIOSH-approved respirators should be used. Do not exchange parts of different respirators. (For example, do not use a cartridge produced by Company "A" with a respirator produced by Company "B" as the combination may not provide adequate protection to the user). Dust masks are ineffective in protecting against herbicide vapors. Similarly, the filters on tractor cabs are intended to remove dust and are not designed to protect against pesticide vapors or mists. Chemical cartridge respirators are recommended for outdoor use when mixing and applying pesticides.

When carrying out operations, change filters each day. The cartridge should be replaced when chemical odour becomes apparent or when breathing becomes difficult. New cartridges should always be installed at the beginning of spray season. Prior to commencing work, check the face seal while the respirator is on the wearer's face. Regardless of design, respirators cannot be worn securely by people wearing beards, moustaches or sideburns.

Face Shields

Goggles offer protection, but frequently full-face protection is advised or required according to the pesticide label. It is especially important to protect your eyes and face when pouring or mixing liquid concentrates. Effective face shields are made of clear plastic.

Since the shield attaches to the hard hat, you can raise or lower it as needed.

Avoiding Spray Drift

To minimize the risk of drift, follow these guidelines:

  • Do not use air-blast or air-mist sprayers to apply herbicides.
  • Do not spray in winds above 20 km/h (12 mph).
  • Avoid using nozzle pressures above 45 psi (300 kPa).
  • Use a minimum of 45 L/acre (10 gallons/acre) water for all herbicides unless otherwise specified for the product.
  • Do not spray when the wind is blowing towards a nearby sensitive crop, shelterbelt or garden.
  • Select nozzles that will produce uniform patterns, correct application rates and low drift hazards. For most conditions, 80o flat fan nozzles produce a better combination of pattern uniformity and drift control than do flooding nozzles, 65o or 73o flat fan nozzles, or cone nozzles.
  • Refer to the Manitoba Agriculture, Food and Rural Initiatives publication "Field Sprayers" and the fact sheet "Calibration and Metric Conversions for Farm Sprayers" for additional information on spraying equipment and calibration.

Laundering Pesticide Soiled Clothing

Skin can absorb chemicals from clothing and equipment that have not been handled and washed properly. Additionally, improper laundering can result in contamination of the washing machine or dryer.

Just as the operator needs to be cautious when handling pesticides, the person doing the laundry needs to be cautious when handling pesticide soiled clothing.

Container Disposal

Rinse all containers prior to disposal to reduce environmental contamination caused by open dumping of unwanted containers.

Triple Rinsing

Triple rinsing renders used pesticide containers (metal, plastic, glass) more than 99.9 percent free of residues, in most cases. Recent data shows that over 78 percent of pesticide containers are being rinsed by farmers. Here are the steps that should be followed:

  • Empty contents of the container into the spray tank and drain in a vertical position for 30 seconds.
  • Add a measured amount of rinse water or other dilutent so container is about one-fifth full.
  • Rinse the container thoroughly and pour the rinsate into the spray tank.
  • Repeat the procedure two times; it should only take about 5 minutes in total.
  • Triple rinsed containers should be punctured or broken to render them non-reusable. Paper bags should be rinsed once prior to disposal.

Pressure Rinsing

Also available are pressure rinsers that can rinse all sizes of empty pesticide containers that can be lifted into position over the spray tank. A 30-second rinse with a pressure rinser is convenient and just as effective as triple rinsing. Pressure rinsers are constructed to be thrust into the bottom of a metal can or plastic jug.

Holes, situated laterally in the rinser tip, direct water from a pressurized source against the inner sides of the container and effectively wash the residual pesticide into the spray tank.

Some farmers have found it convenient to attach a rinser to the pump on their large water storage tank to minimize container handling. Pressure rinsers have the added advantage of rendering containers useless by automatically puncturing them.

Disposal of Containers

Properly rinsed containers should be delivered to a designated pesticide container disposal site. Contact your Agricultural Representative or Weed Supervisor for the locations of pesticide container disposal sites in your municipality.

Pesticide Formulations and Compatibilities

Abbreviations associated with product names indicate the type of formulation.
Abbreviations most often used are:

  • E or EC = emulsifiable concentrate
  • W or WP = wettable powder
  • SC = spray concentrate
  • WDG = wettable dispersable granules
  • DF = dry flowable

When tank mixes are being considered follow any specific label instructions and check label for incompatibilities. Compatibility is usually better if WP is mixed with WP. EC formulations are more likely to cause compatibility problems when mixed with WP formulations.

Compatibility charts only indicate physical mixing properties and do not indicate chemical interactions and for that reason are not included in this guide.