Safety Systems

Maggie Scarbrough

Safety systems like closed mixing and loading systems, enclosed application systems and pesticide containment systems, are investments that pesticide handlers should consider. They are excellent for handlers who handle large amounts of pesticides or who handle pesticides that are dangerous. Occasionally these will be required, not optional.


Some products will require the use of a closed mixing and loading system. These are designed to keep pesticide from coming in contact with handlers during these processes. This is the case with pesticides that can cause acute and delayed effects. Labeling will warn you of these situations. Sometimes a state will require their use.


There are two types of the closed mixing and loading systems: those that use mechanical devices to move the pesticide from container to equipment and those that use soluble packaging.


A mechanical system uses equipment that can remove the pesticide from its container, transfer it, rinse the container, and put it into the application equipment. Generally they are for use only with liquid formulations. They are often custom made and use commercial parts. Unfortunately, they cannot be used with all pesticide containers due to the variance of shape and size.


Mechanical closed mixing and loading systems move the concentrate either by gravity or by suction. Sometimes gravity systems are referred to as “punch and drain systems.” In a gravity system, an unopened container is placed inside of a chamber and is then sealed inside. The material is drained into the mixing tank once a punch has cut a hole in the pesticide container. A nozzle that is attached to the punch can then rinse the interior of the container. This allows the rinse to flow into the mix tank as well. The pesticide container can then be disposed of. You can only use this type of system with a full container. It can be used with dry concentrates as well.


A hose and pipe combination are used to move pesticides in a suction system. Some pesticide containers have a built-in probe that is inserted. These can also rinse the container and transfer system and rinse water will be mixed in as well. If you are not going to use all of the pesticide in the container, the system must have a way to measure the amount that is suctioned. Some of these systems will not allow you to reseal the container and they are also difficult to use if the solution is highly viscous.


Soluble packaging allows the handler to just place the entire package into the mixing tank where the container will dissolve. The negatives include accidental pesticide release if the package is exposed to water and a high risk of splashing when adding the package to the tank.


Closed systems may allow for less protective gear during activities. Substitution of long-sleeved shirts and pants for personal protective equipment may be possible. Chemical-resistant gloves and aprons may be necessary if the closed system is used for concentrated pesticides. Eyewear may be needed if the system is being used under pressure.


Even if you choose closed systems, you should keep protective gear available at the site. This is in case of a mechanical breakdown or spill.


An excellent way to reduce exposure during some application is by the use of an enclosed application system. These involve an enclosure that completely surrounds you and prevents contact with the pesticide. These systems include, an enclosed cab, enclosed cabs with air filtering ventilation systems, enclosed cabs with vapor-removing ventilation systems and enclosed cockpits. Each of these may allow you to wear less personal protective gear. However, you should have the gear with you in the enclosed system. You may have to get out during application and the gear would be necessary. If you get out during application, be sure to remove the gear before you get back in. It should then be stored either outside of the cab or in a tightly sealed container that you can take with you.


If you know you will usually be mixing and loading at one site, it is good to invest in a pesticide collection pad or tray. They can catch any overflow, spills, leaks, etc. You can wash them with water and recover the lost pesticide for re use or disposal. Some of these are small enough to be portable while others are larger and require installation. In the long run they will save money and help protect the environment. They reduce waste and protect the mixing and loading area more efficiently.


Sites where only a small amount of pesticide is mixed and loaded are good candidates for a collection tray. It should be made of chemical-resistant rubber or plastic. It should also have a rim to collect the leaks and spills, as well as a spout to pour out contents. Trays are smaller and more portable.


Collection pads are better or sites where large quantities of pesticide are handled. Often this will be outdoors or in a large, open building. The pad has to be made of waterproof material. Porous surfaces are unacceptable. The pad should also be concave and have enough room to handle a large amount from spills or leaks. An automatic sump system or manual pump are also essential to recover the lost material. This pad should be placed out of the way of irrigation or rainwater to prevent overflow. It would also have to be washed out every day after use.