Fluazifop-p-butyl Registration Review Focus Meeting Held. On July 31, 2014 the OPP 

registration review team met with representatives from USDA and Syngenta to discuss use and 

usage, and previously submitted studies. Fluazifop-p-butyl is a selective, post-emergent herbicide 

registered for the control of perennial and annual grass weeds. Currently, it is registered for use on a 

number of food and feed including soybeans, cotton and carrots. It is also registered for use on 

lawns/turf. The registration review docket initiating a 60-day public comment period on the 

Fluazifop-p-butyl is scheduled to open December 2014, and will include a Preliminary Work Plan 

and supporting documents. 

Participants

BEAD: Sepehr Haddad, Bill Phillips, Steve Smearman

EFED: Nick Federoff, Edmund Wong, Jean Holmes, Brian Anderson

HED: Michael Metzger, William Donovan, Stephen Dapson, Alexandra LaMay

PRD RMIB2: Matthew Manupella, Cathryn Britton, Kevin Costello 

RD: Kathryn Montague, Shanta Adeeb

USDA: Jill Schroeder, Sheryl Kunickis

Syngenta: Tamara Murphy, Adora Clark, Amber Goetz

Dialing in: Jerry Wells, Paul Moore, JiSu Bang, Ted Valenti, Russell Underwood

Discussion Summary

1. The team discussed a previously submitted soil crosswalk report (MRID 49188707), “Evaluating 

the comparability of Foreign Soils used in Environmental Fate Studies for Fluazifop-P-butyl with the use Area 

Soils in the United States.” Syngenta will be submitting a soil crosswalk report for five additional 

soil types not covered in MRID 49188707. Syngenta presented data showing soils collected from 

the European sites (MRIDs 46190602, 87493, 16246545) used in laboratory environmental fate 

and behavior studies for fluazifop-P-butyl and fluazifop-butyl, could be found in areas of 

geographical, climatic, and geo-physicochemical conditions similar to soils in the label uses for 

fluazifop-P-butyl in the United States. 

2. EPA expressed a need for analytical chemistry methods capable of identifying and quantifying 

each separate enantiomer and fluazifop-butyl and fluazifop-acid in soil, water, and tissue. 

Syngenta will be submitting a chiral soil analytical method final report upon completion in early 

2015. Fluazifop-butyl and fluazifop-P-butyl have similar toxicological profiles. Syngenta 

proposed that no chiral methods should be required for water and fish tissues based on similar 

toxicological findings between the R and racemic mixture and no significant epimerization of R 

to S enantiomeric forms have been found in soil or plants. Syngenta will be submitting a 

justification to waive the need for chiral analytical methods for water and fish tissues.

3. Metabolite 5-trifluoromethyl-2-pyridone (TFP) was identified as a residue of concern in plants 

for risk assessment purposes by the 2004 Metabolism Assessment Review Committee (MARC), 

which was unable to conclude that TFP is significantly less toxic than the parent based on 

structural considerations. Syngenta will be submitting pharmacokinetic and toxicological data, 

showing TFP was found to be acutely not toxic, not toxic after repeated administration for 28 

days, and was not a fetal developmental toxicant in rats. Syngenta will submit supporting 

documents for the TFP metabolite.