Mixing, Loading, and Application of Pesticides

Mixing, loading, and application are the primary pesticide handling tasks. They are also among the most hazardous aspects of a handler's job. Never try to cut corners where safety is concerned, and do not assume that every job will be like every other. For example, even though you are familiar with a pesticide, take the time to read the labeling -- important directions are changing more often than in the past, and new information may have been added.

Safe Mixing And Loading Practices

Pesticide handlers are most often exposed to harmful amounts of pesticides when mixing or loading concentrated pesticides. Handlers who mix and load concentrated pesticides with high acute toxicity have an especially high risk of accidental poisoning. By observing some simple precautions, you can reduce the risks involved in this part of your job.

Select an Appropriate Area

Choose the pesticide mixing and loading area carefully. It should be outdoors or in a well-ventilated area away from unprotected people, animals, food, other pesticides, and other items that might be contaminated. Choose a place with good light, especially if you are working at night. Be particularly careful not to mix or load pesticides indoors unless lighting and ventilation are adequate.

Protect Your Water Source

Avoid mixing or loading pesticides in areas where a spill, leak, or overflow could allow pesticides to get into water systems. Protect your water source by keeping the water pipe or hose well above the level of the pesticide mixture. This prevents contamination of the hose and keeps pesticides from back-siphoning into the water source. If you are pumping water directly from the source into a mix tank, use a check valve, antisiphoning device, or backflow preventer to prevent back-siphoning if the pump fails.

Personal Protective Equipment

Before opening a pesticide container, you must put on the appropriate personal protective equipment. By law, you must use all of the personal protective equipment that the pesticide labeling requires for mixers and loaders. Consider using additional personal protective equipment in certain mixing and loading situations.

Opening Containers

Do not tear paper or cardboard containers to open them. Use a sharp knife. Clean the knife afterwards, and do not use it for other purposes. Open containers of pesticides only when they are sitting on a flat, stable surface. If they are tipped on an angle or are in an unstable position, they can easily spill over or leak out when the seal is broken.

Transferring Pesticides

When pouring any pesticide from its container, keep the container and pesticide below face level. This will avoid a splash, spill, or dust from getting on your face or into your eyes and mouth. If there is a wind outdoors or a strong air current indoors, stand so the pesticide cannot blow back on you.

Spills

To prevent spills, close containers after each use. Even if you plan to mix more pesticide soon, close the container tightly each time. Never leave a tank unattended while it is being filled. It may overflow and contaminate the area.

If you splash or spill a pesticide on yourself while mixing or loading, stop right away and remove your contaminated clothing. Wash thoroughly with a mild liquid detergent (or soap) and water as quickly as possible. Put on clean personal protective equipment. Then clean up the spill.

Empty Pesticide Containers

Even after it appears that all the pesticide product has been removed from a container, it usually is not truly empty. The pesticide that clings to the inside of the container can be dangerous to you, other people, and the environment. Take care of empty containers at once.

If containers are rinsable, rinse them as soon as they are empty. Return all pesticide containers to the pesticide storage area or the container holding area when you finish your task. Do not leave them unattended at the mixing, loading, or application site. Never give pesticide containers to children to play with or to adults to use.

If you have empty pesticide containers that cannot be refilled, reconditioned, recycled, or returned to the manufacturer, crush, break, or puncture them. This will make the containers unusable and may also save storage space. Dispose of containers in accordance with label directions.

Nonrinsable containers -- You may not be able to rinse bags, boxes, and other containers of dry pesticides, because the container will not hold up to the rinsing. You also may not be able to rinse containers of ready-to-use pesticides, because there is no place to put the rinsate. Containers that cannot or should not be rinsed must be emptied as completely as possible. Shake or tap the container to remove as much of the pesticide product as you can. Drain containers of liquid pesticides for at least an additional 30 seconds.

Rinsable containers -- When you are diluting pesticides, you should rinse the empty pesticide containers, unless the labeling directs you not to. Such rinsing often saves money, because each rinse removes pesticide from the sides and bottom of the container and allows you to add it to the pesticide mixture. If you rinse empty pesticide containers thoroughly, you usually can dispose of them as nonhazardous waste.

Glass, metal, and plastic containers, plastic-lined paper or cardboard containers, and even unlined paper or cardboard containers that can withstand the rinsing process should be triple rinsed or pressure rinsed. The liquid you use for rinsing should be the diluent (water, kerosene, high-grade oil, or another liquid) listed on the pesticide labeling for diluting the pesticide for application. After rinsing, add the rinsate to your pesticide mixture.

To triple rinse a container:

  1. Empty the container into the tank. Let it drain an extra 30 seconds.
  2. Fill it one-fifth to one-fourth full of water.
  3. Replace the closure and rotate the container for about 30 seconds. Invert the container so the rinse reaches all the inside surfaces.
  4. Drain the rinse water from the container into the tank. Let the container drain for 30 seconds.
  5. Repeat steps 2 through 4 two more times for a total of three rinses.

Applying Pesticides Safely

Every time you apply pesticides, you have two major responsibilities:

Personal Protective Equipment

By law, you must wear the personal protective equipment and other clothing that the pesticide labeling requires for applicators. Consider using additional protection for some types of pesticide application tasks. You may need to weigh several factors before you can make good decisions about the personal protective equipment you should wear.

Hand-carried application equipment -- When you carry the application equipment, such as hand-held sprayers or shake cans, you risk being directly exposed to the pesticide. A dripping or partially clogged nozzle, an unfastened cap, a leaky hose, or a loose connection are extremely likely to cause exposure. Consider wearing extra personal protective equipment to protect the area of your body that is in contact with the equipment.

Entering the path of the released pesticide -- Many applications performed while on foot cause you to walk into the path of the pesticide you are releasing. Whenever possible, apply pesticides so that you are backing into the untreated area, away from where the pesticide is being released. Under many conditions, however, it is unsafe to walk backwards in an application site.

If you must walk into the path of the released pesticide, consider wearing shin-high or knee-high boots, or protective footwear with chemical-resistant pants. Spraying a thick coating of fabric starch or fabric stain protectant on the lower legs of your coveralls can provide a temporary barrier for low-toxicity pesticides and also makes the coveralls easier to clean.

Whether you are walking or riding, if the pesticide is not directed downward or if it remains suspended in the air long enough to cause exposure to the front of your body, consider wearing an apron or chemical-resistant suit. If the pesticide mist or dust reaches as high as your face, consider a dust/mist respirator and eye protection.

Walking into a just-treated area -- You may need to walk into an area that you have just treated. For example, you may need to repair or adjust the equipment or check the pesticide dispersal. Consider putting on additional personal protective equipment.

If the vegetation in the treated area is covered with pesticide spray or dust and is fairly short, consider shin-high or knee-high boots, or protective footwear with chemical-resistant pants. In this situation, as with walking into the path of the released pesticide, it may be useful to apply spray starch or fabric stain protector to the pants legs.

If spray is dripping or dust is falling from overhead, consider a hood or wide-brimmed hat in addition to the body protection and footwear. A dust/mist respirator and protective eyewear may be necessary, too.

High-exposure applications -- Certain types of pesticide applications pose a special exposure risk, because they engulf you in pesticide fallout. They include:

Whenever you work in these situations, large amounts of pesticide fallout are likely to be deposited on your skin and clothing, often to the point of completely drenching or covering you. Usually, you cannot avoid this exposure, even if you perform the application in conditions of little or no air currents.

Applications in enclosed spaces -- Pesticides sometimes are applied in enclosed spaces such as warehouses, factories, homes, and other buildings; railcar, ship, and truck cargo areas; silos, elevators, and other grain storage areas; and greenhouses. When you use pesticides in enclosed spaces, you increase the risk of being exposed to the pesticide by inhalation. You may need to use a respirator even if you would not need one for the same application outdoors.

Adjusting pesticide-coated equipment -- You may need to wear a protective apron while doing some types of equipment adjustments and repairs.

Applying in air currents -- If you will be applying pesticides into or across wind or air currents, consider wearing extra personal protective equipment, because pesticide may be blown onto you. More body protection, protective eyewear, and a dust/mist filtering respirator may be appropriate.

Applying concentrates -- You may be exposed to highly concentrated pesticides during some applications. Ultra-low-volume concentrates and fumigant formulations may be close to 100-percent active ingredient and often are highly toxic. Consider using extra personal protective equipment when applying concentrates, such as that required for mixing and loading of those formulations.

Application Procedures

Every time you apply a pesticide, follow these basic procedures to make sure that you are using the pesticide safely and effectively:

Deliver the pesticide to the target -- Take the time to be sure that the pesticide is reaching the surface or space to which you are directing it. Pesticide that is deposited elsewhere is a waste of time and money and may harm the nontarget areas.

Check the delivery rate -- Check to be sure that you are applying the pesticide evenly and in approximately the right amounts. No puddles of liquid pesticide or mounds of dry pesticide should be deposited in the application area. Be especially careful in areas where you turn or pause. Many types of application equipment will continue to release pesticide even when not in motion.

Check for appearance -- As you apply, notice whether the pesticide you are releasing looks the way it should. Applications of wettable powders usually have a whitish color. If the liquid is clear, check to be sure that you are agitating the mixture enough to keep the wettable powder mixed with the water. Granules and dusts should appear dry and should not form clumps. Emulsifiable concentrates usually look milky. If the pesticide does not look right, be sure that you have the right mixture and that it is still blended evenly.

Check the appearance of the target area where you have just released the pesticide. If the surface is changing colors or is stained unexpectedly, stop and check whether you are harming the surface.

Avoid nontarget organisms -- Before you apply a pesticide, clear all unprotected people from the area. Also remove any pets or livestock that are not being treated with the pesticide. Check the pesticide labeling to find out when people and nontarget animals can go back into the application area. Even if the pesticide labeling has no such instructions, do not allow anyone to enter the treated area at least until any dusts and mists have settled out of the air and any vapors have dispersed.

Avoid nontarget surfaces -- When possible, remove from the application site any items that should not be contaminated with pesticides. Cover or protect any items that cannot be removed from the area and that are not involved in the handling activity. Items that should be removed or covered include such things as food and food utensils; bedding; toys; pet or livestock feed, water, or supplies; and other items that could transfer pesticides to people, pets, or livestock.

Operate equipment safely -- Turn off your equipment whenever you pause for any reason. Take special care to turn it off before making any adjustments or repairs. When you stop application to take a break, to move to another site, or for repairs, depressurize any pressurized tanks. Turn off the main pressure valve on the tank and release any pressure remaining at the nozzles.

After Mixing, Loading and Application

As soon as you finish mixing, loading, or applying a pesticide, you should do a few important follow up tasks. Take the time to clean up properly. Wash your pesticide equipment and then wash yourself. Return equipment to its designated place and safely store or dispose of all pesticide materials and other chemicals that you have used. Be sure that your work site presents no hazards to people or to the environment. Never leave the site unattended until everything has been cleaned up and put away. While you can still remember the facts, make a record of what you have applied and the conditions at the application site.

Equipment Cleaning

Always clean mixing, loading, and application equipment as soon as you finish using it -- do not leave equipment with pesticides on or in it at the mixing and loading site or at the application site. When the job is completed and the tank or hopper is empty, return the equipment to the designated equipment cleanup area.

Benefits of correct cleaning -- Sloppy cleanup practices are one of the main causes of equipment failure or malfunction. Never keep excess pesticides in your equipment for more than a short time. Even small amounts of pesticide residues that are left in equipment can damage it.

Cleaning procedures -- After the equipment is empty, clean both the inside and outside thoroughly, including nozzles or hopper openings. Sometimes you may need to use the diluent used in the pesticide mixture (kerosene or high-grade oil), special cleaning agents, or water under pressure. In other cases, ordinary water may be enough.

Collect the rinsate -- the liquid that results from the washing process. If you do not have a way to reuse or dispose of the rinsate, limit the amount of material you use, so you will create less waste.

Rinsates -- Remember that the rinsates you create when you clean your equipment contain pesticides and can be harmful to people and the environment. Do not allow rinsates to flow into water systems, including sink or floor drains, rainwater culverts, wells, streams, lakes, and rivers. Do not create puddles that children, other unprotected persons, or animals could get into.

You may use equipment rinsate as a diluent for future mixtures of pesticides, if:

The rinsate cannot be added to a pesticide mixture if:

If you have any rinsates that you cannot use, dispose of them as you would excess pesticides.

Personal Cleanup

When you finish working with pesticides or pesticide- contaminated equipment, take time for personal cleanup. Wash the outside of your gloves first, before taking them off. Then carefully peel back your personal protective equipment to avoid getting pesticides on your skin. Remove any other clothing that has pesticide on it.

If you cannot take a shower right away, use a mild liquid detergent and warm water to wash your face, hands, forearms, and any other area that may have pesticides on it. As soon as you can -- no later than the end of the work day -- wash your whole body and hair thoroughly with a mild liquid detergent and plenty of warm water.

When you remove your personal protective equipment and work clothing, put it in a plastic box or bag until it can be laundered. Do not allow children or pets to play with these items. Do not wash work clothing and personal protective equipment in the same wash water with the family laundry.

Recordkeeping

Keeping records of pesticide use and application is a good idea. Records can establish proof of proper use. If an error has been made, records are helpful in finding the cause. They also can provide you with information to use in response to claims of excess residues or damages.

Records can help you reduce pesticide mistakes or misuse. If a pest is not controlled, if damage has occurred in the target area, or if a pesticide has moved off the target area and caused problems, you may be able to determine what went wrong. Then you can take steps to avoid such a situation in future pesticide applications.

Authors:
Philip G. Koehler, University of Florida
Robert A. Belmont, Florida Pest Control Association

This file is part of the UF/IFAS Basic Pesticide Training manual (SM-59) which is intended to provide intermediate training to pest control operators. The manual was adapted from a larger manual, Applying Pesticides Properly, which was developed by Ohio State University in cooperation with the Cooperative Extension Service, U.S. Department of Agriculture, and the Office of Pesticide Programs, U.S. Environmental Protection Agency.

Published: March, 1998