EPA Draft Contains Dicamba Concerns

LINCOLN, Neb. (DTN) -- A new EPA draft ecological risk assessment released Thursday finds the herbicide dicamba potentially adversely affects birds, mammals, bees, freshwater fish, aquatic vascular plants, and non-target terrestrial plants, with the "primary risk of concern" for non-target terrestrial plants through spray drift and volatilization.

In addition, the agency said it found no evidence new measures put in place in October 2020 for over-the-top applications helped reduce the number of off-target incidents.

"Numerous non-target plant incidents have been reported to be associated with the use of dicamba," EPA said in a news release.

"Since the initial registration of OTT (over-the-top) uses in 2016, there has been a substantial increase in the overall number of reported non-target plant incidents which appear to be linked to the OTT uses. EPA continues to monitor the incidents information for dicamba."

DTN has documented issues with off-target dicamba movement through a number of stories, webinars and discussions leading up to the over-the-top registration in 2016 and through the 2022 season.

In December 2021, the agency released a summary of OTT dicamba-related incident reports from the 2021 growing season. The EPA said the incidents were primarily associated with drift and/or volatilization.

"Despite the control measures implemented in EPA's October 2020 dicamba registration decision, the 2021 incident reports showed little change in number, severity, or geographic extent of dicamba-related incidents when compared to the reports it received before the 2020 control measures were required," the agency said.

"EPA is currently working with states and affected stakeholders to gather available incident information for the 2022 growing season."

Dicamba is currently undergoing routine registration review in the U.S. and the draft risk assessments are part of that review. Dicamba is the active ingredient in a range of agricultural and non-agriculture weed control products sold by a range of companies.

The EPA conducts registration reviews for all approved pesticide active ingredients every 15 years. Dicamba was first approved by the EPA in 1967.

EPA said on Thursday it was reviewing whether "OTT dicamba can be used in a manner that does not pose unreasonable risks" to non-target crops and other plants, or to listed species and their designated critical habitats.

In addition, the agency said it was evaluating "all regulatory options" for addressing future dicamba-related incidents.

"EPA's decisions will continue to consider information submitted by, as well as discussions with, scientists, academics, state agriculture extension agents, pesticide registrants, growers, the U.S. Department of Agriculture, the Association of American Pesticide Control Officials, and the State FIFRA Research and Evaluation Group," the EPA said.

"The agency is committed to acting in a transparent manner, following well-established regulatory processes, while upholding its mission of protecting human health and the environment."

The EPA has launched a 60-day public comment period on the latest assessment.

In addition, the EPA issued an addendum to a March 2016 human health risk assessment for new dicamba uses. That assessment found no inhalation risks of concern except for occupational handlers. The agency expanded the assessment in May 2016 to include all uses subject to registration review.

In 2021, EPA completed a second addendum that superseded both assessments. The agency released that addendum for public comment on Thursday, including updated data that only identifies occupational handler inhalation risks of concern for mixing and loading of dry flowable formulations for aerial and ground-boom applications.

"EPA found no dietary, residential, aggregate, or post-application risks of concern," the EPA said in the announcement.

After reviewing public comments, the EPA said it will create a proposed interim decision set for completion in 2023.

That decision may include possible risk mitigation to "address any potential risks of concern identified in the dicamba DRAs," EPA said in a news release.

DTN has contacted key postemergence dicamba purveyors Bayer and BASF regarding the risk assessment. "We are reviewing the draft documents that the EPA published on Aug. 18, and we plan to formally submit our perspective for the EPA's consideration during the 60-day public comment period that is now open," Bayer said in a statement to DTN. BASF had not yet responded at posting time.

Read the EPA risk assessment here: https://www.regulations.gov/…

Read more on DTN:

"Proposed Changes to Dicamba," https://www.dtnpf.com/…

Todd Neeley can be reached at todd.neeley@dtn.com

Follow him on Twitter @DTNeeley

(c) Copyright 2022 DTN, LLC. All rights reserved.