US EPA addresses ecological risks posed by aminopyralid

On April 23, the U.S Environmental Protection Agency (EPA) is releasing for public comment the proposed interim decision (PID) for aminopyralid, a pyridine herbicide used to control broadleaf weeds and woody brush in both agricultural and non-agricultural settings. The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) requires EPA to periodically review pesticides to ensure that risk assessments reflect the best available science. The PID is part of a multi-step process to identify risks as well as actions that can mitigate risks.   

Based on the findings in the 2020 draft ecological risk assessment and feedback submitted during the public comment period, EPA is proposing new measures to reduce potential spray drift to protect non-target organisms. Additionally, the agency is proposing the following new mitigation measures to address potential residues in compost in the aminopyralid PID:

Prohibiting off-site composting of treated plant matter and manure from grazing animals until residues have adequately declined to reduce compost contamination;
Requiring a clean-out period of at least three days for animals fed with treated plant materials;
Requiring pasture and turf applicators to notify the property owners/operators of the compost prohibition, and for the applicator to keep a record of this notification for two years;  
Updating compost pictogram on pesticide labels showing users when not to compost materials; and,  
Requiring registrants to participate in a stewardship program and provide educational outreach for those affected by herbicide residues in compost.
Upon publication of the Federal Register notice, public comments will be accepted for 60 days in docket ID number EPA-HQ-OPP-2013-0749 at www.regulations.gov.  

After a thorough review of the science and carefully considering scientific peer review and public comments, EPA will proceed with the registration review process for aminopyralid. The next step in the FIFRA registration review process is the interim decision, which finalizes any required risk mitigation measures to reduce the ecological risks.

Additional information on the pyridine and pyrimidine herbicides proposed and interim decisions can be found on EPA's website.

Background   

Aminopyralid is a pyridine herbicide used to control broadleaf weeds and woody brush in both agricultural and non-agricultural settings. Agricultural use sites include wheat, corn, pasture and rangeland. Non-agricultural use sites include conservation reserve program land, forests, rights of ways, industrial areas and other non-agricultural sites.