Every day, handlers and applicators transfer potentially hazardous chemicals and concentrates such as herbicides, insecticides, fungicides, and liquid fertilizers from large drums into smaller containers or mixing tanks. This transfer process can have serious consequences if manual “tip-and-pour” techniques or poorly designed pumps are used.
In fact, each year 1,800 to 3,000 preventable occupational incidents involving pesticide exposure are reported. Keeping workers safe is not just a best management practice — it is the law. The federal Worker Protection Standard was revised in 2015 and now provides a greater focus on reducing pesticide exposures.
“When handling pesticides, toxicity and corrosiveness are the main dangers, but even organic pesticides can be harmful if there is exposure,” says Dr. Kerry Richards, President Elect of the American Association of Pesticide Safety Educators and former Director of Penn State’s Pesticide Safety Education Program. “No matter what their toxicity level, all chemicals — even those that are organic — are a particular contact exposure risk if they are corrosive.”
In addition to the potential for injury, there can also be serious financial ramifications for the grower or ag product manufacturing facility if pesticides or liquid chemicals spill.
“Beyond workers compensation issues related to exposure, there can be other huge potential liabilities: EPA (federal) or state regulatory fines, as well as clean-up or remediation costs,” says Richards. “This is particularly true if a pesticide gets into a water source, kills fish, or contaminates drinking water.”
The Costs of Lost Containment
Richards, who works with the National Pesticide Safety Education Center, has seen and heard many examples of worker and environmental exposure from pesticides in over 30 years of pesticide safety education experience. “Exposure risk is highest for those loading chemicals into mix tanks because it is more concentrated and hazardous before diluted with water,” she says. “Any time you lose containment of the chemical, such as a spill, the risks can be serious and spiral out of control.”
Corrosive chemicals, for example, can severely burn skin or eyes, and many chemical pesticides are toxic when touched or inhaled. “Some organic herbicides are so highly acidic that they essentially burn the waxy cuticle off the above ground parts of plants, killing them,” says Richards. “If you splash it in your eye or on your skin, it can burn in the same way and cause significant damage.”
Some chemicals are flammable as well, and if not properly handled and contained, can be ignited by sparking from nearby motors or mechanical equipment. The danger of a fire spreading can be serious both in the field and at ag product manufacturing facilities.
In addition to the cost of clean-up or treating injuries, substantial indirect costs can also be incurred. These include supervisors’ time to document the incident and respond to any added government inspection or scrutiny, as well as the potential for slowed grower production or even a temporary shutdown at the manufacturing plants.
“The direct and indirect costs of a pesticide spill or injury can be substantial, not the least of which is the loss of wasted chemicals,” says Richards. “Pesticides, particularly newer concentrated formulations, are very expensive so spilling a few ounces could cost several hundred dollars in lost product during a single transfer.”
Chemical Transfer Techniques
Traditional practices of transferring liquid chemicals suffer from a number of drawbacks. Manual techniques, such as the tip-and-pour method, are still common today. Tipping heavy barrels or even 2.5 gallon containers, however, can lead to a loss of control and over pouring.
Although a number of pump types exist for chemical transfer — such as rotary, siphon, lever-action, piston and electric — most are not engineered as a sealed, contained system. In addition, these pumps can have seals that leak, are known to wear out quickly, and can be difficult to operate, making precise volume control and dispensing difficult.
In contrast, closed systems can dramatically improve the safety and efficiency of chemical transfer. California’s Department of Pesticide Regulation, in fact, requires a closed system for mixing and loading for certain pesticides so handlers are not directly exposed to the pesticide.
“The availability of new technology that creates a closed or sealed system is ideal for handling pesticides or other dangerous chemicals, and should become a best management practice,” suggests Richards. “With such devices, as the GoatThroat Pumps, pesticide handlers can maintain a controlled containment from one vessel to another and significantly reduce any potential for exposure or spill.”
A sealed system delivers liquids to an intermediate measuring device and is useful for low toxicity liquids. A closed system moves the material from point A to point B through hoses using dry-break fittings on the connection points. This prevents leaking and exposure to the handler which helps guarantee safety. Liquids are transferred from the source container, into the measuring system, and then to the mix tank.
Small, hand-operated pressure pumps are engineered to work as a system which can be either closed or sealed. The pumps can be used for the safe transfer of over 1,400 industrial chemicals, including the most aggressive pesticides.
These pumps function essentially like a beer tap. The operator attaches the pump, presses the plunger several times to build up a low amount of internal pressure, and then dispenses the liquid. The device is configured to provide precise control over the fluid delivery, from slow (1 milliliter per 1 ounce) up to 4.5 gallons per minute, depending on viscosity.
Because such pumps use very low pressure (<6 PSI) to transfer fluids through the line and contain automatic pressure relief valves, they are safe to use with virtually any container from 2-gallon jugs to 55-gallon drums. This keeps expenses to a minimum, with the important bonus of increasing the safety of handlers by reducing the potential exposure to the chemical, which can assist with Worker Protection Standard regulatory compliance.