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Atrazine closed system advisory
The US Environmental Protection Agency (EPA) has required supplemental labeling for pesticide products containing atrazine since October 2004. That labeling includes the following statement:
“Mixers and loaders supporting aerial applications at a rate greater than 3 lbs ai/A must use a closed system that meets the requirements for dermal protection listed in 40 CFR 170.240(d)(4) and must: wear the personal protective equipment required for mixers and loaders, wear protective eyewear if the system operates under pressure, and be provided and have immediately available chemical resistant footwear for use in an emergency, such as a spill or equipment breakdown.”
Further, the supplemental label states, in part,

“Water-soluble packets when used correctly qualify as a closed mixing/loading system under 40 CFR 170.240(d)(4).”
Oregon requested further clarification from EPA on the above statements.

EPA response
In response to requests for clarification, the Oregon Department of Agriculture consulted with the EPA to answer three questions:
  1. Does the “stinger method” qualify as a closed system?
  2. Does the 250-gallon “tote method” qualify as a closed system?
  3. If an operator used 3 lbs ai/A liquid atrazine and 1 lb ai/A DF atrazine (in water-soluble packets) to make up the desired application rate of 4 lbs ai/A, and loaded the solution without using a “closed system” would it be considered a violation of the supplemental atrazine labeling, aforementioned?
In short, the answers were no, sometimes and yes. More detailed responses follow.
Remember, when performing any chemical handling that the proper PPE must be used in accordance with the label of the product being handled. Read and follow the label instructions.

Stinger method
Picture of stinger
Figure 1
The “stinger method” employs a “stinger” (fig. 1) that is attached to a metered pump and draws liquid from a 30-gallon drum into a batch tank. This method would not be considered “closed system” as defined in 40 CFR 170.240(d)(4) because of the multiple opportunities for the handler to come into contact with the pesticide.
Closed system 30 gal drum
Picture of 30 gallon drum with Micro-Matic
Figure 2
Certain equipment is available for 30 gallon drums that is considered "closed system." The following is an example of how to use equipment that would fall in to this category. The user should read and fully understand the operating instructions prior to using the equipment.
  • Insert a closed system adaptor with a suction tube such as the Micro-Matic assembly into a 30 gallon drum and connect a closed system suction line to the closed system valve, then remove the chemical using the closed system.
  • After the drum has been pumped out, remove the second bung and rinse the drum using a rinsing nozzle (designed for rinsing the insides of chemical containers), remove the rinsate through the closed system (fig. 2).
  • After the drum is rinsed until clean and rinsate is removed, then the rinsed closed system assembly may be transferred to another drum and this procedure repeated.
This procedure will allow the applicator to aerial apply Atrazine 4L up to the 4 lb a.i. per acre rate for aerial applications, conforming with the label’s closed system requirements.

Mini bulk tanks or totes
Picture of dripless coupler on tote
Figure 3
Atrazine 4L is available in 250 -275 gallon totes which have a hatch on the top and a 2 inch connector and valve on the bottom.

If the tote is connected without a dripless connector, there is a space between the tote’s outlet valve and the transfer hose hookup, which can hold a small amount of liquid. Upon disconnecting the hose, the handler may come into contact with the product present in the space. The EPA does not consider this type of hookup to be a "closed system."
If a coupler or valve system is utilized that makes the system completely dripless, the criteria for a “closed system” may be met.
To use these as a closed system,
  • Remove the cap on the bottom connector, then attach a dry break valve.
  • Empty the container through the dry break valve.
  • When emptied, rinse the container thoroughly and remove the rinsate through the dry break valve.
  • When the rinsate is emptied, remove the dry break valve and then attach it to the next tank (fig 3).

WSP plus liquid atrazine
If an operator used 3 lbs ai/A liquid atrazine and 1 lb ai/A DF atrazine (in water-soluble packets) to make up the desired application rate of 4 lbs ai/A, and loaded the liquid without using a “closed system” it would be considered a violation of supplemental atrazine labeling. If the desired final application rate is greater than 3 lbs ai/A (liquid, DF or any combination thereof), you must use a closed system to transfer the solution to the application equipment. This guidance applies only to products containing atrazine and that have the supplemental label language agreed upon by atrazine registrants and the EPA in 2004. Always read and follow pesticide label directions.

Additional information