Worker Protection Standard creates questions

The greenhouse and nursery industries encounter a lot of pesticide-use situations that are somewhat difficult to interpret under general Worker Protection Standard guidelines. I ran across the following on the Dip N Grow Web page. The questions generally pertain to treated potting soil, moving plants and non-contact activity. I hope you find them helpful.

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Entry restrictions -- Potting soil in pots

Q. If potting soil is treated with a pesticide in one location in a nursery or greenhouse and then placed in pots and used to produce plants in another area of the nursery or greenhouse, is the treated area the soil and therefore any REI restrictions would continue to apply in the second location?

A. Yes. The treated area is the area to which the pesticide was directed. In this case, the soil in the pots is the treated area. Therefore, any REI and associated requirements would continue to apply after the application. if the treated area is moved in containers, the REI and associated requirements are in effect for the treated area (Feb. 28, 1995).

Potting soil -- Movement off site

Q. If the treated soil is sold (in the pots with the crop) and moves off site, do any REI and other treated-area restrictions apply?

A. No. if the treated area in a pot with the crop is moved off the agricultural establishment, it is no longer covered under WPS. Therefore, no WPS requirements will apply at the new location. However, any label specific non-WPS REIs or other labeling restrictions must be met. (Feb. 28, 1995)

My note: If the crop is sold to another greenhouse for further production, the REIs are still in effect until the time runs out!

Moving containers during an REI

Q. If the soil/plants in pots are treated, can the container be moved during the REI?

A. Yes, the container may be moved provided there is no contact with the treated area by workers. If only the soil is treated and not the pot along with the soil such as in an overhead spray, then any REI restrictions apply only to the soil which has been treated. Moving the pot without any contact with the soil would not be in violation of the REI.

If plants are treated, a worker can move containers provided there is no contact with the plants or other treated surfaces, and pesticides cannot drop or drip onto the worker. If the pesticide application is directed at the container and plant, then both are considered the treated area and are subject to any REI restrictions. In either of the above situations, the notification requirements, found at 40 CFR 170.120, apply to the treated area whether it is the soil/plant or the soil/plant and pot. (Feb. 28, 1995)

My note: It is difficult to meet the requirements of only treating the soil. Drenches are one way to do this. A drench is applied with a low-pressure apparatus within 12 inches of the soil surface.

Spraying 12 inches from planting medium

Q. The 40 CFR part 170.110 lists entry restrictions for greenhouses and nurseries associated with pesticide applications. One criterion for determining entry restrictions is spraying at a height of greater than 12 inches from the planting medium. In greenhouses with hanging baskets, is the 12-inch height measured from the top of the medium?

A. Yes. (Feb. 28, 1995)

Entry under an REI for no-contact activities

Q. May an unprotected worker enter a treated area under an REI immediately after the application if it is for activities with no contact?

A. Yes. An unprotected worker may enter a treated area immediately after the application is finished as long as any inhalation exposure level or ventilation criteria listed on the labeling has been reached, and he will have no contact with anything that has been treated with pesticide including pesticide residues on plants, on or in the soil, in water, or in the air. (March 7, 1995)

My note: Four hours is the minimum time that must be observed for ventilation after any pesticide application, in any manner. Many labels say a registered product has a “zero” hour REI. This is technically incorrect and remains an unresolved U.S. EPA labeling error. I say it is better to be safe than sorry.

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- Charles C. Powell

July 2008