US EPA paraquat requirements place spotlight on closed transfer system

The liquid herbicide paraquat is widely used throughout North America as an effective herbicide and pre-harvest crop defoliant, but can be fatal if accidentally ingested in small quantities as well as cause eye damage and irritation to skin.

In response to the serious risks associated with paraquat, the EPA has already pursued significant manufacturer labeling and training changes. Now, for growers, the next step in the process is to address changes required to safely dispense the restricted-use pesticide. Consequently, it is urgent that growers quickly get up to speed on what the EPA has mandated in terms of new closed transfer systems required to safely dispense the restricted-use pesticide.

“There are some big changes in the EPA’s rules for paraquat use, and growers need to understand and follow them to remain in compliance,” says Kerry Richards, Ph.D., Director of Delaware's Pesticide Safety Education Program.  “Otherwise, there could be some hefty fines.”

By September 2020, new container standards for paraquat will take effect, with “closed-system packaging for all non-bulk (less than 120 gallon) end use product containers of paraquat,” according to the EPA.

The agency will require “new closed-system packaging designed to prevent transfer or removal of the pesticide except directly into proper application equipment. This will prevent spills, mixing, pouring the pesticide into other containers or other actions that could lead to paraquat exposure,” states EPA’s website.

Paraquat containers from manufacturers will need to be completely sealed, with no screw caps, adaptors or other ways to open and decant the chemicals. To prevent accidental exposure or spills while transferring the liquid herbicide to smaller containers (for mixing or use), certified applicators must also utilize a closed transfer system that connects to the sealed container and cannot be easily circumvented.

Closed transfer systems are specifically designed to transfer liquids safely, while preventing accidental exposure to the concentrated/diluted pesticide or rinse solution. Unfortunately, the EPA is leaving it to growers to engineer their own solutions or find solutions already on the market.

“The grower is going to have to figure out which closed-transfer systems meet the specific EPA requirements to the letter, and if they don’t get it right, they could get fined,” says Richards.

Although many types of closed transfer systems exist, many do not satisfy this new EPA mandate because they can be breached or circumvented in some way.

Within this category are gravity-assisted inversion systems, which are inserted into containers using adaptors and flipped upside down. The adapter depresses a valve so the chemical flows freely out of the container. However, gravity-assisted inversion systems can be easily circumvented and the chemicals decanted if the valve is pressed when the container is not properly seated in the adapter.

Container breaching systems are another alternative. With this approach, sealed 1 to 2.5-gallon containers of product would be placed in an enclosed system and then pierced so the liquid contents drain to the bottom before being fed through hoses to the application equipment.  A water input valve can also be used to safely rinse out the enclosure. The downside is that each grower would have to purchase a container breaching system to use the product at all, and partial container use would not be possible.

Probes inserted into containers for fluid extraction are also commonly used for volumes ranging from 10 to 120 gallons. Because the container doesn’t have to be inverted, like a gravity-assisted device, a larger vessel can be used. However, when the probe is extracted, it is a breach of the closed system. Also, there is no safe or compliant way for growers to rinse out the container after use.

Fortunately, the industry is responding to growers’ need to comply with the EPA’s new closed-system mandate. One industry leader, GoatThroat Pumps, a Milford, Conn.-based pump designer and manufacturer, is developing a system to specifically comply with EPA paraquat use requirements. In fact, California, the largest agriculture-producing state, already requires a closed transfer system for Category 1 pesticides, and the company already produces products that meet those exacting requirements.

The small, versatile, hand-operated pressure pumps are engineered to work as a system, complete with everything needed to move liquids from the source container through measuring and into the mix tank with a simple triple-rinse set-up.

The hand pump version functions 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. A one-touch valve allows growers and pesticide handlers to execute a controlled, steady transfer of liquids from one container to another, and the flow rate can be adjusted from gallons to drops based on their needs. Other systems can be connected through no spill connectors to extraction devices such as the Chem Traveler.

Because the 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 closed container.  Systems are available for 2.5-gallon containers, 5-gallon containers and for all 30- and 55-gallon drums and barrels including Micromatic.

The fact that the pump is hand-operated is ideal for application in areas where there is no access to electricity.

According to Richards, this type of pump is not only for paraquat, but can also be used for a variety of other ag chemicals that growers already use by utilizing various adaptors available from the pump manufacturer.

“Using a hand-operated, closed-transfer pump system will not only help growers meet the new EPA paraquat standards by September, 2020, but also enhance the safety and ease of use of many other chemicals growers are pouring and mixing every day,” says Richards.