On Dec. 22, NAAA submitted comments to the Environmental Protection Agency (EPA) on the final pesticide registration review documents for 2020. The first of the 2021 registration review comments were submitted on Jan. 4. The EPA is required by the Federal Insecticide Fungicide and Rodenticide Act (FIFRA) to review the registrations for all crop protection products every 15 years. The comments submitted on Dec. 22 dealt with risk assessments that the EPA conducts for each active ingredient being reviewed. The comments submitted on Jan. 4 were on proposed interim decisions, which are being used by the EPA instead of a full reregistration of a product because the biological evaluations and pollinator protection assessments still need to be completed for most products.
The risk assessments are the “first round” of documents written by the EPA during the pesticide registration review process. They rely heavily on models to assess the risks the pesticides pose to the environment and human health. The human health risk assessments model the risks to consumers, bystanders and pesticide handlers. The proposed interim decisions are the last phase of the review process. They use the risk assessments as basis for deciding whether a product should be reregistered and what restrictions should be placed on how it is used. While risk assessments may find a risk of concern related to aerial applications of a product, it is the proposed interim decision that might place restrictions on the use of aerial applications.
The proposed interim decisions NAAA commented on were for lambda-cyhalothrin and gamma-cyhalothrin, methomyl, myclobutanil, naphthalene acetic acid, salts, ester, acetamide, and triphenyltin hydroxide (TPTH). The decisions for lambda-cyhalothrin and gamma-cyhalothrin found risks of concern to mixers and loaders for aerial applications and proposed banning the aerial application of gamma-cyhalothrin to high-acreage field crops, which NAAA opposed citing the importance of aerial application for treating these crops. NAAA suggested the use of both a closed loading system and an elastomeric half facepiece cartridge respirator to reduce the risk to mixers and loaders. The proposed interim decision also recommended a buffer zone near aquatic sites, which NAAA indicated needs to be wind direction-based, as drift cannot move upwind. NAAA also opposed a maximum wind speed of 10 mph and proposed 15 mph instead, citing numerous labels and interim decisions that allow aerial application in winds speeds up to 15 mph.
In comments on the proposed interim decisions for methomyl, NAAA made the same arguments in favor of wind direction-based buffer zones and against a 10 mph wind speed restriction. The label statements proposed by the EPA in the interim decisions for myclobutanil and naphthalene acetic acid, salts, ester and acetamide were acceptable, so NAAA commented as such. The proposed interim decision for triphenyltin hydroxide (TPTH) recommended requiring the use of both a closed loading system and an elastomeric half facepiece cartridge respirator for mixers and loaders of aerial applications; NAAA agreed with this requirement. NAAA also argued in favor of wind direction-based buffer zones and against a 10 mph wind speed restriction for TPTH.
The risk assessments NAAA submitted comments for on Jan. 4 were for difenoconazole, fenbuconazole, mesotrione, pyrasulfotole, tembotrione, thiram, tolfenpyrad, topramezone and ziram. All of the risk assessments were done using the Tier 1 model in AgDRIFT to estimate drift from aerial applications. This model uses many inaccurate assumptions and substantially overestimates the risk of drift associated with modern aerial applications. These faulty assumptions include a smaller than commonly used droplet size, a swath displacement shorter than industry standards, a slight inversion present during the application despite being prohibited on the label, wind speed measured at a height appropriate for ground applications instead of aerial applications and modeling the application to bare ground instead of a standing crop. NAAA referred the EPA to a letter submitted to the EPA’s Office of Pesticide Programs in June 2020 for a detailed analysis of all the inaccuracies of the Tier 1 model and how to use the Tier 3 AgDRIFT model to improve the accuracy of aerial drift estimates. A few of the risk assessments did examine the use of larger spray droplets in order to reduce drift. NAAA supported this concept but pointed out droplet size is only one variable in the AgDRIFT model and that the EPA needs to address all of NAAA’s concerns with Tier 1, not just droplet size.
NAAA will be commenting on EPA registration review documents throughout 2021 and into 2022. NAAA commented on pesticide registration review documents for 77 pesticide active ingredients in 2020 and expects to comment on a minimum of 50 in 2021, including paraquat, glyphosate and chlorpyrifos.
This work reiterates the importance of supporting NAAA’s efforts through your membership. Your operation depends on products labeled for aerial application, and you depend on NAAA for ensuring you have access to those products.