Bicyclopyrone: Response to Public Comments on EPA's "Proposed Registration of the New 

Active Ingredient Bicyclopyrone" (Docket ID: EPA-HQ-OPP-2014-0355) 

Summary 

This document summarizes the U.S. Environmental Protection Agency's (the agency, EPA) 

responses to public comments received through the public notification ofthe receipt ofthe 

application for registration of the new active ingredient bicyclopryone, and the announcement of 

the proposed decision to conditionally register bicyclopyrone under Section 3(c)(7)(C) of the 

Federal Insecticide, Fungicide, Rodenticide Act (FIFRA). 

On 8113114, EPA published a notice of receipt in the Federal Register of an application for 

registration of bicyclopyrone and announced a public comment period of 30 days. No comments 

were received. On 9/5114, the EPA published a notice of filing in the Federal Register 

announcing the receipt of the initial filing of the bicyclopyrone petition by Syngenta under the 

Federal Food, Drug, and Cosmetic Act (FFDCA) requesting the establishment of regulations for 

residues of bicyclopyrone on various commodities. This publication also announced a public 

comment period of 30 days; seven comments were received on the FFDCA notice of filing. 

Three of the comments were relevant to bicyclopyrone, the other four comments were relevant to 

other actions that were batched together with bicyclopryone in the same Federal Register 

document. The commenters noted that pesticides and bicyclopyrone pose a risk to pollinators. 

The agency has determined that bicyclopyrone is moderately to practically non-toxic to young 

adult honey bees (A pis mellifera) on an acute exposure basis. On 2/ 11/2015, the EPA published 

an additional notice of filing in the Federal Register for the import tolerance on sugarcane 

petition and no rel evant comments were received. 

The EPA announced the proposed decision of the unconditional registration of bicyclopyrone on 

3113115, and held a public comment period for 30 days, closing 4/ 13/ 15. Forty four submissions 

were received in response to the public commenting period. Forty one submissions were in favor 

of and supported the registration of bicyclopyrone and three submissions were in opposition to 

the agency's proposed decision to register bicyclopyrone. One of the submissions in opposition 

to registration was a mail campaign submission containing 5,558 individual letters. The 

agency's review and responses are summarized in this document. 

Summary of Comments Supporting the Agency's Proposed Decision 
Forty one submissions were received from various uni versities, state corn grower associations, 

state agri-business associations, state farm bureaus, state food processors associations, IR-4, 

Syngenta, and the public in favor of and supported the registration of bicyclopyrone noting its 

benefits of controlling hard to control weeds such as cockle bun·, ragweed, etc., helping with 

herbicide resistance management, its ability to be used as part of a one-pass spray system, and 

reduction of the use of atrazine, S-metolachlor, and mesotri one. 

Comment: Christopher Lish (Document ID: EPA-HQ-OPP-2014-0355-0060), Mail 

Campaign submitted by Jonathan Evans, Center for Biological Diversity (Document ID: 

EPA-HQ-OPP-2014-0355-0063, 5558 individual comments), and Center for Biological 

Diversity, Brett Hartl, Director (Document ID: EPA-HQ-OPP-2014-0355-57). 

A number of comments were submitted related to non-target species and policies for protecting 

endangered species. Specific areas cited by the public included: 

"l'm ·writing to you with a simple request: When considering approval for new and potentially 

harmful pesticides like bicyclopyrone and AcuronTM,follow the law and first consult with 

wildlife experts. The Endangered Species Act requires federal agencies--including the 

Environmental Protection Agency (EPA)--to consult with the U.S. Fish and Wildlife Service 

(USFWS) and National Marine Fisheries Service (NMFS) before taking any action that could 

potentially harm wildlife protected under the Act. And yet, too often, this rule is ignored or not 

followed and harmful pesticides are rubber stamped for approval." 

''The National Academy a/Sciences has provided clear guidance to the EPA on the importance 

of a rigorous analysis of pesticide impacts to endangered species, and the requirement to consult 

with the FWS and the NMFS is written directly into the Endangered Species Act. I demand that 

this consultation be pe1jormed before bicyc/opyrone, AcuronTM, or any other such pesticide 

earns your agency's approval. " 

"EPA has an independent duty under the Endangered Species Act to consult with the U.S. Fish 

and Wildlife Service and National Marine Fisheries Service on the registration of any new active 

ingredient I end-use product/hat may affect protected species. " 

"The new corn herbicide bicyc!opyrone,for instance, has potential to harm endangered species, 

both on its own or mixed with other pesticides like atrazine, a known endocrine disruptor to 

amphibians. Millions of pounds of atrazine are used in this count1y and have been found in 

swface water in concentrations far exceeding the threshold/or harming wildlife. Studies have 

also shown that pesticides can have synergistic effects when mixed with other chemicals, causing 

greater harm to species than either chemical would alone. Fast-tracking bicyclopyrone's 

approval for use on millions of acres of corn would be an unthinkably irresponsible move." 

"Label and use restrictions required to protect listed species ... " 
EPA Response: 

The agency has been working collaboratively and actively with the USFWS and the NMFS 

(Services) to design a framework for efficiently completing the consultation process for pesticide 

actions in accordance with the Endangered Species Act (ESA). The agency is focusing most of 

its resources for assessing impacts to listed species on the agency's registration review program 

for currently registered or existing pesticides. EPA believes that, as a general matter, currently 

registered and existing pesticides may present a greater degree of risk to listed species than most 

new chemistries coming to market, and that it is therefore environmentally preferable in most 

circumstances for EPA to assess the impacts of existing pesticides sooner in the process than 

newer pesticides that are designed to compete with more risky alternatives. EPA does not 

believe the environment or the public would be best served by delaying the registration of 

bicyclopyrone to complete consultation. 

EPA received numerous comments from various universities, state com grower associations, 

state agri-business associations, state farm bureaus, state food processors associations, IR-4, 

Syngenta, and the public requesting an expedited registration of bicyclopyrone noting its benefits 

of controlling hard to control weeds such as cockle burr, ragweed, etc., helping with herbicide 

resistance management, its ability to be used as part of a one-pass spray system, and reduction of 

the use of atrazine, S-metolachlor, and mesotrione. Acuron TM can provide its most effective 

weed management with a single pre-emergent application that may not require additional postemergent applications. AcuronTM can provide higher efficacy on difficult to control weeds with 

a lower rate of atrazine, S-metolachlor, and mesotrione; resulting in decreases in the amount of 

atrazine that will be applied to corn as well as smaller reductions in S-metolachlor and 

mesotrione. AcuronTM's introduction will result in reduction in the use of other Syngenta 

products, resulting in a reduction of 3.6 million pounds of atrazine per year on acres that would 

of have been treated vvith those products. The agency is requiring Syngenta to achieve this 

reduction no later than the 2020 growing season. In the event that these reductions are not 

achieved, EPA has a mechanism in place to ensure future atrazine reductions. 

Focusing EPA's, f'WS', and NMFS' limited resou~ces on completing a consultation on the 

effects of bicyclopyrone would by necessity come at the expense of putting more resources into 

evaluating - and consequently regulating, where appropriate - what EPA believes to be more 

toxic compounds. 

EPA currently employs a 3-pronged strategy in managing pesticide registration actions. This is 

intended to protect listed species and their designated critical habitat by focusing resources on 

areas where we can achieve the most important protections. First, EP 1\ will undertake the 

majority of its ES/\ consultation work through registration review. This allows EPA to focus on 

chemicals with higher risk, i.e., the ·'worst first", resulting in the greatest potential benefits for 

listed species. EPA has also negotiated with our pru1er agencies to phase in the interim scientific 

approaches over time. In 1 ovember 20 I 3. EPA. USPWS. MFS, and US Department of 

Agricultmc (USDA) released a white paper containing a summary of their joint interim 

approaches for assessing risks to listed species from pesticides. These interim approaches were 

developed jointly by the agencies in response to the ational/\cademy of Sciences (NAS) 

recommendations. and rc f1 ect a common approach to risk assessment shared by the agencies as a 
way of addressing scientific differences between the EPA and the Services. Details ofthe joint 

interim approaches are contained in the ovember I, 2013 white paper, Interim Approaches for 

National-Level Pesticide Endangered Species Act Assessments Based on the Recommendations 

of the National Academy (~(Sciences April 2013 Report. EPA, FWS, and NMFS are continuing 

to develop and "vorl toward implementation or the interim approaches to assess the potential 

risks or pesticides to listed species and their designated critical habitat, and will apply these 

approaches to initial consultations and, based upon the experience gained with these approaches 

as well as any new science that may develop, modify procedures as appropriate. 

Secondly, EPA intends to complete an endangered species assessment for new herbicide tol erant 

crop uses. The agency believes this is appropriate since these registrations would be expected to 

greatly increase the number of acres treated for a currently registered pesticide. This current 

action does not involve transgenic seeds. 

Thirdly, EPA will provide information that compares the potential hazards of the new active 

ingredients to already registered pesticides with similar use patterns. This will allow 

stakeholders to compare the relative toxicity of the proposed registration to available 

alternatives. The agency will proceed with registration in those instances where there would be a 

favorable shift to the new active ingredient and could chose to conduct an ESA assessment for 

those instances where the new active ingredient poses greater risks to non-target organisms prior 

to making a registration decision. EPA concludes the overall environmental benefit for this 

action is consistent with these policy priorities. 

For the reasons explained above, EPA has not dete1mined whether consultation with the Services 

under section 7 of the ESA for bicyclopyrone would be necessary. The agency believes that the 

reduction in the amount of atrazine and the other pesticides would provide an environmental 

benefit and support the registration of this new active ingredient. However, EPA is currently 

working to prioritize its consultation activities with the Services and will evaluate the appropriate 

timing and scope of any necessary consultation on bicyclopyrone in connection with those 

efforts. In addition, to the extent EPA receives new information indicating that bicyclopyrone 

may pose a greater risk to listed species than indicated by the existing scientific database for this 

pesticide, EPA will re-evaluate the terms of registration and detennine whether additional use 

restrictions to protect listed species are necessary. 

Concerning synergistic effects, the agency does not routinely include a separate evaluation of 

mixtures of active ingredients. However, there are some data available to the agency regarding 

synergistic effects and EPA believes it adequately addressed the issue of synergism between 

bicyclopyrone and atrazine. Although the submitted data and EPA risk assessments tend to 

focus on individual chemicals, for AcuronTM, a formulation where there are multiple active 

ingredients, each is subject to an individual risk assessment for a regulatory decision regarding 

the active ingredient on a particular use site. In the case of AcuronTM, this would be for each 

active ingredients contained in the formulation (i.e., bicyclopyrone, mesotrione, atrazine, and Smetolachlor). If effects data are available for a formulated product for non-target organisms 

containing more than one active ingredient, they may be used qualitatively or quantitatively in 

accordance with the agency's Overview Document and the Services' Evaluation Memorandum 

(USEPA 2004; USFWS/NMFS/NOAA 2004). 
Additionally, for atrazine and bicyclopyrone specificall y, the agency compared the AcuronTM (a 

mixture of bicyclopyrone, mesotrione, atrazine and S-metolachlor) formulation-specific acute 

toxicity data with atrazine only and bicyclopyrone only active ingredient specific acute toxicity 

data. All three formulations demonstrated low acute toxicity for mammals. The acute toxicity 

effects for all three formulations are simi lar and do not indicate a synergistic effect for atrazine 

and bicyclopryone for mammals. 

If evidence from incidents or field observations suggest that cutTcnt label language is not 

providing adequate protection to non-target organisms, county specific use limitations may be 

required. To the extent that county-specific label mitigation is needed, EPA would use the web 

application "Bulletins Live Two" (BLT)" to set fourth geographically-specific pesticide use 

limitations for the protection of threatened and endangered species and their designated critical 

habitat. BL T can be found at http://\n\" .cpa.uov/oppfeacll /cndanuer/hulletins.htm. 

Comment: Syngenta Crop Protection, LLC, (Document ID: EPA-HQ-OPP-2014-0355-66) 

'"In the document "Proposed Registration ofthe New Active Ingredient Bicyc/opyrone" (EPAHQ-OPP-201-1-0355-0024), on page 6 (2nd Paragraph and associated tables), the Lemna gibba 

EC50 (mg/L) listed for bicyclopyrone contained a typographical error of0.003 mg/L instead of 

the correct EC50 value of0.0/3 mg/L. See page 32 in EPA-HQ-OPP-20/.f-0355-0015 for the 

EC50 and NOECfor L. gibba (0. 013 mg/ L and 0. 003 mg/L, respectively). The correct EC50 

value was used in the risk assessment conducted by EFEp, and the typographical correction 

suggested here is for the tables in the Proposed Registration document only. The updated 

comparison tables are provided below. Additionally, we have added isoxajlutole to the tables 

below for additional comparison since it is also a preemergence HPPD inhibitor regisfeJ·ed in 

corn. 

EPA included comparative tables for three taxa (terrestrial plants, mammals, and vascular 

aquatic plants), based on the screening level assessment, stating "Only groups of organisms for 

which LOCs are exceeded/or bicyclopyrone are listed. " (EPA-HQ-OPP-2014-0355-0024, page 

6). Additionally, bicyclopyrone has a favorable toxicity profile for all other taxa for which 

EPA 's screening level assessment showed no LOC exceedances. Forfuture analysis of 

bicyclopyrone, the tables in Allachment I provide a comparison ofthe toxicity o.fbicyclopyrone 

relative to alternative herbicides .for additional environmental endpoints. We suggest that jillure 

comparative analyses should also utilize overall risk comparisons (exposure as well as toxicity). 

These additional comparisons show that this new herbicide provides a highly favorable 

environmental profile. 

EPA conducted screening level assessments in the document "Environmental Fate and 

Ecological Risk Assessment for Use of the New Herbicide Bicyclopyrone (NOA4-19280)" (EPAHQ-OPP-201 -1-0355-0015). Additional data and methodologies are available for use in future 

assessments to jitrther refine the highly conservative assumptions implicit in the screening level 

assessments. Such refinements include use of foliar degradation data and residue decline, 

refinement ofrunoffscreening estimates using established models such as PRZM edge of field 

flux data with chemical specific environmental fate data, terrestrial and aquatic plant recovety 
data, and other best available data and methodologies. In addition, label mitigations added by 

EPA to minimize drift and runoff (25 fool downwind buffer, droplel size requiremenls, wind 

speed, elc.} could be used to refine !he screening level assessmem. Use oflhese refinemenls 

results in risk and exposure conclusions that are below levels of concern for listed and non-lis!ed 

species." 

EPA Response: 

The agency acknowledges the typographical error and has revised the table with the correct 

EC50 value of 0.013 mg/L in the decision document. Isoxatlutole was not included in the tables 

because it was not identified among the top alternatives to bicyclopyrone in corn. The agency 

will use all available information and methods as appropriate, in evaluating any future 

bicyclopyrone actions.