2 

### Table of Contents

Contents

I. INTRODUCTION .................................................................................................................. 3

A. Summary of Sulfentrazone Registration Review ..............................................................4

B. Public Comments ..............................................................................................................5

II. USE AND USAGE .............................................................................................................. 9

III. SCIENTIFIC ASSESSMENTS ......................................................................................... 10

A. Human Health Risk Assessment ...........................................................................................10

1. Risk Conclusions ........................................................................................................ 10

2. Human Incidents ......................................................................................................... 10

3. Tolerances ................................................................................................................... 11

B. Ecological Risk Assessment ............................................................................................... .11

1. Risk Conclusions ........................................................................................................ 12

2. Ecological Incidents ................................................................................................... 14

3. Characterization of Ecological Risk ........................................................................... 14

C. Benefits Assessment ....................................................................................................... ......15

D. Endangered Species Assessment ..........................................................................................17

E. Endocrine Disruptor Screening Program ...............................................................................18

IV. INTERIM REGISTRATION REVIEW DECISION......................................................... 19

A. Risk Mitigation and Regulatory Rationale ......................................................................19

B. Tolerance Amendments ...................................................................................................20

C. Endangered Species .........................................................................................................21

D. Interim Registration Review Decision ............................................................................21

E. Data Requirements ..........................................................................................................21

V. NEXT STEPS AND TIMELINE .......................................................................................... 22

A. Interim Registration Review Decision ............................................................................22

B. Implementation of M itigation Measures .........................................................................22

Appendix A: SULFENTR AZONE Label Table .......................................................................... 233 

### I. INTRODUCTION

This document is the Environmental Prot ection Agency’s (EPA or the Agency) Interim Registration Review Decision for Sulfentrazone (case 7231, PC code 129801) and is being issued pursuant to 40 CFR sections 155.56 and 155.58. A regist ration review decision is the Agency's determination whether a pesticide meets, or does not meet, the standard for registration in the Federal Insecticide, Fungicide, and Rodenticid e Act (FIFRA). The Agency may issue, when it determines it to be appropriate, an Interim Registration Review Deci sion before completing a registration review. Among other things, the Interim Registrati on Review Decision may: 1) require new risk mitigation measures; 2) impose interim risk mitigation measures; 3) identify

additional data or other information re quired to complete the review; and 4) include schedules for submitting the required data, conducting the new risk assessment, and completing the registration review. For furt her information on sulfentrazone, additional documents can be found in EPA’s pub lic docket (EPA-HQ-OPP-2009-0624) at www.regulations.gov

.

FIFRA, as amended by the Food Quality Pr otection Act (FQPA) of 1996, mandated the continuous review of existing pest icides. All pesticides distributed or sold in the United States generally must be registered by the EPA based on sc ientific data showing that they will not cause

unreasonable risks to human health or to the environment when used as directed on product labeling. The registration review program is intended to make sure that, as the ability to assess and reduce risk evolves and as polic ies and practices change, all regi stered pesticides continue to meet the statutory standard of no unreasonable a dverse effects. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review program, the Agency periodically re-evaluates pes ticides to make sure that as these changes occur, products in the marketplace can continue to be used safely. Information on this program is provided at www.epa.gov/oppsrrd1/registration_review/ . In 2006, the Agency implemented the registration review program pursuant to FIFRA s ection 3(g) and will review each registered pesticide every 15 years to determine whether it continues to meet th e FIFRA standard for registration.

EPA is issuing an interim registration review decision for sulfentrazone so that it can (1) move forward with aspects of the registration review that are complete and (2) implement interim risk mitigation. The Agency is curren tly working with the U.S. Fish and Wildlife

Service and the National Marine Fisheries Se rvice to develop met hodologies for conducting national endangered species assessments for pest icides. Therefore, although EPA has not yet fully evaluated risks to threatened and enda ngered species, the Agency will complete its endangered species assessment and any necessa ry consultation with the Services for sulfentrazone prior to completing the sulfentraz one registration review. Likewise, the Agency will complete endocrine screening for sulfen trazone, pursuant to the Federal Food, Drug, and Cosmetic Act (FFDCA) section 408(p), before co mpleting this registration review. Last, EPA will determine whether additional pollinator exposure and effects data are necessary to make a final registration review decision for sulfentrazone and issue a da ta call-in (DCI) to obtain any such data prior to completing the sulfentrazone registration review.

Sulfentrazone is a broad-spectrum herbicide registered to control broadleaf weeds on a variety of field crops, fruits, vege tables, ornamentals and turf. It is primarily applied as a pre-4 emergent herbicide. Because sulfentrazone wa s first registered in 1997, it was not subject to reregistration.

This document is organized in five sectio ns: the Introduction, which includes this summary and a summary of public comments and EPA’s response; Use and Usage, which describes how and why sulfentrazone is used and summarizes data on its use; Scientific Assessments, which summarizes EPA’s risk asse ssment, any revisions, and risk conclusions; Interim Registration Review Decision, which describes the mitigation measures necessary to

address risks of concern and the regulatory rationale for EPA’s re gistration review decision; and, last, the Next Steps and Timeline for co mpletion of this registration review.

A. Summary of Sulfentrazone Registration Review

Pursuant to 40 CFR section 155.50, EPA forma lly initiated registration review for sulfentrazone (case 7231) in 2009. The following list highlights si gnificant events that have occurred during the registration review of sulfentrazone. Docu mentation of these events for sulfentrazone can be found in EPA’s public docket, EPA-HQ-OPP-2009-0624, accessed at www.regulations.gov :

 September 23, 2009 – Publication of Sulfentrazone Preliminary Work Plan (PWP) for a 60-day public comment period. The Preliminary Work Plan (PWP) was accompanied by the scoping document and problem formulation.

 April 5, 2010 – Final Work Plan (FWP) for Sulfentrazone was issued. Three public comments were received during the 60-day co mment period for the sulfentrazone PWP; however, these comments did not change the risk assessment or data needs identified in the PWP. Therefore, the FW P did not modify the PWP.

 September 28, 2010 – Generic Data Call-In (GDC I) Notice for sulfentrazone was issued.

 July 3, 2014 – EPA published the preliminary ri sk assessments for sulfentrazone for a 60- day public comment period: Preliminary Ecological Risk Assessment for the Registration Review of Sulfentraz one and Proposed New Uses on Apples and Sulfentrazone – Preliminary Human Health Ri sk Assessment for Registration Review and the Risk Assessment for the Section 3 Regi stration Request for a New Use on Apples.

EPA received comments from the Center for Biological Diversity (CBD) and FMC Corporation (FMC), the sulfentr azone technical registrant.

 August 2015 – The Agency published the Sulfentrazone Proposed Interim Registration
Review Decision, dated June 17, 2015, for a 60-day public comment perio d. In addition to that document, the Agency also p ublished the following supporting documents:

o Response to Comments on the Preliminar y Ecological Risk Assessment for the Registration Review of Sulfentrazone;

o Response to Comments on the Preliminary Human Health Risk Assessment for the Registration Review of Sulfentrazone;5 o Addendum to the Environmental Fate and Ecological Risk Assessment for Sulfentrazone Registration Review;

o Sulfentrazone Usage Information; and

o Sulfentrazone Qualitative Benefits Assessment.

 December 2015 – The Agency is now publishing the Sulfentrazone Interim Registration

Review Decision in the registration review docket (EPA-HQ-OPP-2009-0624).

B. Public Comments

During the 60-day public comment period on the Sulfentrazone Proposed Interim Registration Review Decision, which opened on August 8, 2015 and closed on October 9, 2015, the Agency received two comments, from th e sulfentrazone technical registrant, FMC Corporation, and from the Center for Biologica l Diversity (CBD), an environmental and public interest group. FMC’s comments focused on the risk mitigation for sulfentrazone and the timing

of label amendments. CBD’s comments focused on EPA’s obligations under Section 7 of the Endangered Species Act (ESA) to complete a na tional endangered species assessment and to

initiate consultation with the U.S. Fish and W ildlife Service and the National Marine Fisheries Service (the Services) prior to completion of the sulfentrazone registration review. The public comments, and EPA’s response, ar e summarized below. Public co mments in their entirety are located in the docket, EPA-HQ-OPP-2009-0624.

C OMMENTS SUBMITTED BY FMC IN EPA-HQ-OPP-2009-0624-0040

Comment: FMC requests that the time frame to submit amended labels, which implement the label changes summarized in Appendix A of the Proposed Interim Decision Document, be extended to 90 days (rather than the original 60 days) due to th e numerous complexities of the labels and the large numbe r of actively registered sulfentrazone products.

Response: EPA will allow 90 days for submission of amended labels. FMC has over 60 FIFRA Section 3 products registered for sulfentraz one and approximately 50 FIFRA Section 24(c) special local need products. Given the larg e number of sulfentrazone product labels, EPA considers this to be a reasonable request.

Comment: FMC emphasizes that there are other regist rants with active sulfentrazone technical registrations as well as e nd-use product registrations containing sulfentrazone. The proposed label mitigation should apply to all sulfentrazone technical and agricultural end-use products. FMC requests that the Agency notify all registra nts of the required mitigation and that each registrant be required to adhere to the sa me label mitigations at the same time.

Response: The sulfentrazone label m itigation applies to all sulfen trazone technical products and all agricultural end-us e products. Through this document and the associated Notice of Availability, EPA is notifying all affected registrants of (1) th eir obligation to implement the mitigation and (2) the timeframe for submission of amended labels implementing the mitigation.6 Comment: The summary of labeling cha nges for sulfentrazone on page 20 of the proposed
interim decision, includes a the fo llowing statement: “Selec t coarse to very coarse droplet size

when sulfentrazone is used alone and a medium to coarse droplet size when sulfentrazone is tank

mixed with a contact bur ndown herbicide.” FMC’s June 24, 2015 commitment letter 1 , submitted after discussions with the Agency on risk mitigati on, stated that coarse to very coarse droplet sizes should be used when sulfentrazone is app lied as a preemergent/preplant application. There are certain applications where medium to coarse droplet size is requir ed for adequate product performance. Therefore, coarse to very coarse droplet size restrictions should be limited to preemergent/preplant applications.

Response : The Agency has amended the Summary of Labeling Changes for Sulfentrazone to clarify the droplet size to be used during preeme rgent/preplant applications to more accurately reflect the mitigation negotiated w ith FMC. In addition, the Agency is requiring registrants to amend product labels to specify application situations where a me dium to coarse droplet size is required for reasons of product performance.

Comment : The summary of labeling changes for sulfentrazone section, on page 21 of the proposed interim decision, includes the followi ng statement: “Ground applicators must use a finished spray volume of 15 gallons per acre.” FMC’s commitment letter, following discussions with the Agency on mitigation measures, stated th at “A minimum spray volume of 10 gallons per acre is required when applyi ng with ground application equipm ent.” Only when tank mixing with a contact burndown herbicide should 15 gallons per acre be require d. Further detail is provided in the FMC commitm ent letter as point #5.

Response : The Agency has amended the Summary of Labeling Changes for Sulfentrazone to clarify the minimum spray volume to be used to more accurately reflect the mitigation negotiated with FMC, as specified in Section IVA2 of th is document. In addition, EPA has amended the summary of labeling changes to specify “When sulfentrazone is tank mixed with a contact burndown herbicide, ground applicators must us e a minimum spray volume of 15 gallons per

acre.”

Comment : Amended anaerobic soil and aerobic aquatic metabolism reports (MRIDs 49501101 and 49501102, respectively) were submitted to the Agen cy to fully satisfy the data requirement and reclassify their status from supplemental to full. FMC requests that these studies be
reviewed, and if EPA finds these data useful, that the Agency use the data in future risk assessments for sulfentrazone. FMC also requests data evaluation records (DERs) for these reports be provided once they become available.

Response : EPA has received and is reviewing thes e amended study reports. The anaerobic soil and aerobic aquatic metabolism data will be used in future risk assessments for sulfentrazone, including the endangered species assessment, as appropriate. The study DERs will be sent to FMC upon completion of the data review s and added to the public docket.

1 This letter is in the public docket, under EPA-HQ-OPP-2009-0624-0038.7 Comment : As a condition of sulfentrazone registra tion, the Agency required FMC conduct three prospective groundwater monitoring studies on soils highly vulnerable to leaching of sulfentrazone to groundwater. FMC committed to satisfying the conditional registration and submitted numerous progress reports and a final report for each (MRIDs 47453602, 47453601, and 46816001, respectively). FMC believes the condi tion of registration has been fulfilled and requests that the condition of registration be remove d and its status indicated as full. FMC also requests DERs for these reports are pr ovided once they become available.

Response : EPA has received and reviewed th e prospective groundwater studies for sulfentrazone. The Agency will send the comp leted DERs for these studies and inform FMC

whether the submitted data fulfill the condition of registration. However, the decision on the conditional registration is separate from the registration review.

C OMMENTS SUBMITTED BY CBD IN EPA-HQ-2009-0624-0041

Comment : CBD opposes the proposed reregistration of sulfentrazone at this time as premature because they assert that the Agency has determin ed that sulfentrazone ha s the potential to cause adverse effects to species. In CBD’s comments on the Proposed Interim Registration Review Decision for Sulfentrazone, they focus on EPA’s duty to initiate consultation with the U.S. Fish

and Wildlife Service and the National Marine Fisheries Service (the Services) prior to completion of the registration review process for su lfentrazone. CBD states that the reregistration of sulfentrazone cannot be completed in comp liance with EPA’s obligations under both FIFRA

and the ESA until the EPA concludes that the continued use of sulfentrazone will have “no effect” on listed species or criti cal habitat or completes consulta tion. CBD contends that there are readily available data and information sources that would allow EPA to complete Step 1 of

the Interim Approaches for National Level Enda ngered Species Assessments Based on the Recommendations of the Nati onal Academy of Science. CBD refers to their previous comments 2 on EPA’s draft ecological risk assessment, whic h provided specific label language to implement

the Bulletins Live! System, stating that this label language would enable EPA to comply with current and continuing ESA duties. (CBD incorpor ated these and all othe r previous comments on the draft ecological risk assessment by reference. ) Last, they state that EPA must take a precautionary approach and enter into consulta tions with the Services on sulfentrazone as

outlined in the Interim Approaches document.

Response : As an initial matter, CBD’s comments s uggest that it may not fully appreciate the

distinction between EPA’s interim and final re gistration review decision. Additionally, CBD seems to use “reregistration” interchangeably wi th “registration review.” Both are separate programs mandated by FIFRA; sulf entrazone is currently under going Registration Review. As provided in EPA’s registration review regulations at 40 CFR section 155.56, EPA may, in its discretion, issue an inte rim decision before the completion of registration review when, among other things, it determines that it cannot co mplete registration review because additional information is necessary to complete the Agency ’s assessment. In addition, section 155.56 also provides that EPA may require risk mitigation measur es in an interim decision. Consistent with

2 Docket number EPA-HQ-OPP-2009-0624-0018.8 this provision, EPA is issuing this interim regist ration review decision for sulfentrazone in part so that it can move forward with aspects of the registration review decisi on that are complete

while EPA continues to work with the Services on developing the interim approaches that will be used to complete its registrati on review endangered species assessm ent for sulfentrazone. Under section 3(g) of FIFRA, EPA must complete the registration review of sulfentrazone by October 1, 2022. While EPA could, therefore, choose not to complete any aspect of the sulfentrazone registration review for several more years until it completes its endangered species assessment and any necessary consultation, EPA believes th e public and the environment benefit from EPA’s early action on the matters covered by this interim decision -- including risk mitigation, such as use of spray nozzles limiting sulfentrazon e droplet size, a spray minimum release height, limitation on aerial application, and other drift reduction measures -- as described in Section IV

of this document. EPA does not believe the Enda ngered Species Act compels a contrary result. Taking early action to address so me risks now serves to benefit the environment and does not preclude EPA from taking any additional necessary actions to address effects to listed species that EPA concludes are necessary as it works to complete registration review.

Accordingly, EPA’s previous response to CBD’s comments on the draft ecological risk assessment (in the Proposed Interim Decision) stat ed that EPA plans to address CBD’s concerns with the development of its Final Registration Re view Decision. This is still EPA’s plan. EPA anticipates initiating consultation with the Servic es after issuing the Inte rim Registration Review Decision, but prior to issuing the Final Registra tion Review Decision. Th is Interim Registration Review Decision, like the Proposed Interim Decision, states that EPA is not making a complete endangered species finding, and that the Agency ’s Final Registration Review Decision for sulfentrazone will depend upon the results of an ESA Section 7 consultation with the Services, an assessment of nontarget exposure to bees, as well as the results of a FFDCA Section 408(P) endocrine screening.

EPA is still in the process of developing th e interim approaches based on the 2013 NAS Report recommendations, including Steps 1 and 2 of th e Biological Evaluation for listed species. CBD’s previous comments provide reference to the available critical habitat; however, as CBD noted, not all species have critical habitat. Furthermore, critical habitat is just one piece of the species’ range. EPA is working with the Servic es to obtain the best available species range information for all listed species. We are also working together to determine the appropriate pesticide use footprint. EPA will be taking public comment on our interim approaches as developed and implemented for th e three pilot chemical s: chlorpyrifos, diazinon and malathion. As a result, EPA may develop a revised approach for Steps 1 and 2 through work on the three pilot chemicals before completing Step 1 for sulfentrazone.

CBD’s previous comments also provided label la nguage referring pesticid e applicators to EPA’s

Bulletins Live! System, and a statement that all product la bels for sulfentrazone must contain this language. However, since there are no Bulletins for sulfentrazone in Bulletins Live! Two , it is unnecessary, at this point in time, to include this language on the label for sulfentrazone. Inclusion of a reference to Bulletins on the pr oduct label when no Bulletins exist is likely to result in confusion for pesticide applicators and growers. However, EPA is in agreement with CBD that Bulletins are the appropriate mechanis m to implement any necessary geographicallyspecific pesticide use limitations intended to protect listed species. EPA plans to use Bulletins9 Live! Two to implement any Bulletins that would be generated as we complete the evaluation of potential risks of sulfentraz one to listed species and de signated critical habitat.



### II. USE AND USAGE

Sulfentrazone is a soil-applied, pre-emergent herbicide which can be applied either preplant incorporated or preemergence to th e weeds. Sulfentrazone is a protoporphyrinogen Oxidase (PPO) Inhibitor, classified by the Weed Science Society of America (WSSA) as a Group 14 herbicide. WSSA Group 14 herbicides inhibit the protoporphyrinogen oxidase enzyme (important in the production of chlorophyll), causing a peroxidation of lipids in the cell membrane leading to cell leakage. Therefore, first symptoms are water-soaked lesions followed by necrosis of these lesions. Sulfentrazone is ab sorbed primarily by the roots and leads to rapid foliar desiccation (WSSA, 2014) 3 . Because sulfentrazone inhibits seed and propagule germination, it needs to be applied as close to the soil surface as po ssible with the lowest possible amount of pesticide remaining on a ny leaf surfaces and the minimum amount of exposure to evaporation or the wind.

Sulfentrazone is registered for use to cont rol a broad spectrum of broadleaf, grass, and sedge weed species on a wide variet y of field crops, fruits, orname ntals, turfgrass, and vegetable crops. The greatest use of sulfentrazone between 2004 and 2013, in terms of pounds applied, was on soybeans and sunflowers, followed by dry beans and peas and tobacco. In terms of percent crop treated, the greatest use was on t obacco (45-65 percent crop treated), followed by asparagus (15-30%) and dry beans and peas (15-25%).

To supplement the summary information pr ovided above, EPA reviewed national usage data for sulfentrazone for individual crops to pr ovide information for potential refinements to the preliminary risk assessment. EPA compiled su mmary data on average annual acres grown for major agricultural crops treated with sulfen trazone; average annual acres treated with sulfentrazone; the maximum singl e application rate (from product labels), average application rate, and the high-end applic ation rate (between the 80 th and 100 th percentile). The Agency also reviewed data on application timing.

In general, the Agency found that sulfentrazo ne is usually applied at rates below the maximum registered application rate, primarily by ground application in either the early spring (before planting) or late fall (aft er harvest). Proprietary usage da ta show that aerial application of sulfentrazone is limited to a few crops: soybean s in four states, sugarcane in two states, and sunflowers in three states. In addition, EPA foun d that sulfentrazone is often used to control

weeds that have become resistant to other herbicides. Please see the April 6, 2015 memo, Sulfentrazone Usage Information, and the June 4, 2015 memo, Sulfentrazone Qualitative Benefits Assessment , for details.

3 Weed Science Society of America. 2014. Herbicide Handbook, 10 th Edition. Dale L. Shaner Ed. Herbicide

Handbook Committee.10 

### III. SCIENTIFIC ASSESSMENTS

A. Human Health Risk Assessment

A summary of the Agency’s human health ri sk assessment is presented below. The Agency used the most updated Agency science policies and risk assessment methodologies to prepare a quantitative risk assessment in support of the sulfentrazone regi stration review. For a

detailed discussion of the human health assessment for sulfentrazone, see Sulfentrazone – Preliminary Human Health Risk Assessment for Registration Revi ew and the Risk Assessment for the Section 3 Registration Re quest for a New Use on Apples dated June 5, 2014, available in the public docket EPA-HQ-OPP-2009-0624, at http://www.regulations.gov/.

1. Risk Conclusions

EPA has no dietary risks of concern for sulfentr azone from exposure to residues in either food or drinking water. The Agency ha s no risk concerns for residential use of

sulfentrazone on residential turf or golf courses or for use on or namentals. Furthermore, EPA has no risk concern from aggregate exposure to sulfentrazone from food, drinking water, and residential/bystander exposure.

Sulfentrazone does not appear to share a co mmon mechanism of toxicity with other substances. In addition, sulfentrazone does not appear to produce any toxic metabolite or degradate also produced by other substances . Therefore, EPA has not made a common mechanism of toxicity finding for sulfentrazone and any other substance. For more information on EPA’s efforts to determine which pesticides share a common mechanism of toxicity and to evaluate cumulative effects, see EPA’s website, http://www2.epa.gov/pesticide-science-andassessing-pesticide-ri sks/cumulative-assessm ent-risk-pesticides

.

For pesticide handlers receiving occupa tional exposure to sulfentrazone, EPA has no risk

concerns associated with inha lation exposure. However, handle rs who are mixing and loading liquid and dry flowable formulations of sulfen trazone have dermal exposures and risks of concern (for high acreage crops) unless chemical-re sistant gloves are worn. Most sulfentrazone labels require chemical-resistant gloves, and EP A is requiring that th e remaining labels be amended to require chemical-resistant gloves. (See Section IVA1 of this document).

The Agency also evaluated exposure and risk to agricultural workers who enter areas

treated with sulfentrazon e after application. EPA determined that postapplication exposures and risks were not of concern on the day of applicati on. Therefore, the sulfentr azone re-entry interval is based on its acute toxicity, Ca tegory III and the restricted en try interval (RE I) is 12 hours in accordance with 40 CFR 156.208c(2)(iii).

2. Human Incidents

EPA consulted the Office of Pesticide Programs Incident Data System (IDS) for potential human poisonings related to sulfentrazone. Between 2002 and 2009, four incidents were found, with generic symptoms not confirmed to be relate d to sulfentrazone exposu re. In addition, there11 was no clear evidence of a trend or exposure pa ttern. At this time, there is no evidence suggesting a plausible associati on between exposure to sulfentrazo ne and a moderate or severe health outcome. Therefore, the Agency believes that no further investigation of human incidents

is warranted.

3. Tolerances

EPA has determined that there are no a dverse human health effects from use of sulfentrazone. The Agency will pursue changes to the tolerances for sulfentrazone to correct the commodity definition for flax, update crop toleran ces for tree nuts, and correct the tolerance

values for indirect or inadvert ent residues. Specific changes are described in the June 5, 2014 document, Preliminary Human Health Risk Assessment for Regist ration Review and the Risk Assessment for the Section 3 Registra tion Request for a New Use on Apples, and in Section IVB

of this document.

B. Ecological Risk Assessment

A summary of the Agency’s ecological risk assessment is presented below. EPA used the most up-to-date Agency science policies a nd risk assessment methodologies to prepare a quantitative ecological risk asse ssment in support of the registration review of sulfentrazone. When EPA published the prelimin ary ecological risk assessment for sulfentrazone in July 2014, the Agency received extensive comments from FMC on the assessment. These comments prompted revisions to the preliminary ecological risk assessment for sulfentrazone. For a detailed discussion of the ecological assessment for sulfentrazone, see th e following documents, all available in the public docket EPA- HQ-OPP-2009-0624, which can be accessed at http://www.regulations.gov/:

 Preliminary Ecological Risk A ssessment for the Registration Review of Sulfentrazone and Proposed New Uses on Apples , dated June 11, 2014,

 Addendum to the Environmental Fate and Ecol ogical Risk Assessment for Sulfentrazone Registration Review, dated June 9, 2015, and

 Response to Comments on the Preliminary Ecological Risk Assessment for the Registration Review of Sulfentrazone, dated June 9, 2015.

EPA is currently working with the Services and other stakeholders to implement an interim approach for assessing pot ential risk to listed species and their designated critical habitats. Once the scientific methods necessary to complete risk assessments for listed species and their designated critical habitats are fina lized, the Agency will complete its endangered species assessment for sulfentrazone. As such, potential risks to listed species will not be

described further in this document. The risk concerns for nonlisted species only are described herein. The Agency will complete its endange red species assessment for sulfentrazone, and any necessary consultation with th e Services, before completing the sulfentrazone registration

review.12 1. Risk Conclusions

In 2014, the Agency conducted a preliminary ecological risk assessment for

sulfentrazone. This conservative assessment s howed that both acute and chronic risk estimates for mammals, freshwater and estuarine/marine fish, and freshwater invertebrates were below

EPA’s level of concern. 4 This assessment also showed that acut e risk estimates for birds, reptiles, amphibians, and estuarine/marine invertebrates were below the level of concern. Therefore, EPA does not have risk concerns for nonlisted speci es in these taxa for th ese exposure durations.

When initially scoping the registration review for sulfentrazone, EPA did not identify the need for any additional studies to evaluate poten tial effects on pollinators. However, since the

issuance of the June 2014 Guidance for Assessing Pesticide Risks to Bees, 5 EPA has begun to require these data where applicable. EPA is currently determini ng whether additional pollinator data are needed for active ingredient s in registration review whose dockets opened prior to June 2014. For those activ e ingredients where EPA determines that additional pollinator exposure and effects data are necessary to help make a final registra tion review decision, EPA

intends to issue a DCI to obtain these data. In the near future, EPA will provide further information and guidance on this effort. The po llinator studies that could be required for sulfentrazone are included in Table 1 below; th e table does not list studies previously submitted to EPA and found to be acceptable. The Agency will require data it believes are needed to help inform the pollinator risk assessment.

Table 1. Potential Pollinator Data Requirements for Sulfentrazone

Guideline # Study

850.3020 * Acute Contact Toxicity with Adult Honey Bees

850.3030 *† Honey bee toxicity of residues on foliage

850.3040 ‡ Full-Field testing for pollinators
Non-Guideline (OECD 237) * Honey bee larvae acute oral toxicity

Non-Guideline * Honey bee adult chr onic oral toxicity

Non-Guideline * Honey bee larvae chronic oral toxicity

Non-Guideline ‡ Field trial of residues in pollen and nectar
Non-Guideline (OECD 75) ‡ Semi-field testing for pollinators

* Tier 1, laboratory studies. †

‡ Tier 2 and 3 Semi-field and full-field colony level studies. The need for a higher tier test for pollinators will be determined based upon lower tiered tests and/or other lines of data and the need for a refined pollinator risk

assessment.

The preliminary ecological risk assessment show ed potential chronic risks of concern to

birds and to estuarine/marine invertebrates. In addition, the assessment showed risks of concern for terrestrial and semi-aquatic nontarget plants. In these instances, EPA refined the preliminary risk assessment by reviewing additional plant to xicity data; incorpora ting a new plant endpoint, and considering additional usage data for sulf entrazone. In addition, information on typical

4 For nonlisted species, the Level of Concern (LOC) is 1; RQs > 1 exceed the LOC. For listed species, the LOC is 0.1; RQs > 0.1 exceed the LOC.

5 http://www2.epa.gov/sites/ production/files/2014- 06/documents/pollinator_risk_assessment_guidance_06_19_14.pdf13 agricultural practices was considered in order to provide additional context and perspective for

these risk concerns.

Birds. In the preliminary risk assessment for sulfentrazone, the Agency estimated acute and chronic risks to birds, expressed as risk quotients (RQs), usi ng a No Adverse Effects Concentration (NOAEC) from an avian reproduc tive toxicity study and environmental effects concentrations (EECs) of sulf entrazone on various avian food ite ms, grouped together into five generic diets. These EECs were derived from the Kenaga Nomogram. The resulting acute RQs ranged from 0 to 0.02, and were below the Agency’s level of concern for all generic avian diets. However, chronic RQs ranged from 1.18 to 9, for all avian diets except for one (fruits/pods/seeds), and exceeded the Agen cy’s level of concern (1.0).

EPA revised the avian RQs using average ap plication rates repres entative of actual

sulfentrazone use. 6 These application rates varied from 0.05 to 0.3 lb a.i./A. The resulting RQs ranged from 0.2 to 7.2 with all app lication rates exceeding the LOC fo r at least one dietary item. RQs derived from mean Kenaga values ranged from <0.1 to 2.6 with RQs exceeding the LOC for at least one dietary item for all application rates with the exception of the lowest application rate modeled (0.05 lb a.i./A.)

Aquatic Invertebrates. In the preliminary risk assessment, EPA estimated acute and chronic RQs for freshwater and estuarine/mari ne aquatic invertebrate s. EPA provided bounding estimates of exposure and risk to invertebrates in both clear and turbid waters because photolysis contributes to the degradation of su lfentrazone in aquatic environments. 7 Although the preliminary risk assessment indicated that the chronic RQs for estuarine/marine invertebrates exceeded the level of concern, the RQs are based on both the worst-case exposure scenario and a chronic NOAEC of 0.003 mg a.i./L based on an acute-to-chronic ratio. EPA has no chronic toxicity data for the mysid shrimp. There is inherent uncertainty in the use of an acute-tochronic ratio because it represents an unbounded m easure of risk. Therefore, the Agency has low confidence in the chronic risk estimates for mysid.

Terrestrial and Semi-aquatic Plants. Initial Findings

. In the preliminary risk assessment for sulfentrazone, the Agency used the TerrPlant model to calculate RQs for nontarget terrestrial and semiaquatic plants exposed to sulfentrazone from spray drift alone and for spray drift and runoff combined, in both dry upland and semi-aquatic wetland habitats. In addition, EPA examined the effect of spray drift to nontarget plants usi ng the AgDrift model. The preliminary

risk assessment showed risk concerns for nontar get plants from use of sulfentrazone. When sulfentrazone is applied by ground, nontarget plant RQs ranged from 0.17 to 10 for monocots and from 1.1 to 31.9 for dicots. For aerial app lications, RQs ranged from 1.6 to 11 for monocots and from 3.4 to 43 for dicots. Initial spray drif t effects distances ranged from 56 to > 1000 feet from the edge of treated fields.

Revised Risk Estimates. In response to public comments submitted by FMC, EPA revisited the Tier II Vegeta tive Vigor data for cucumber 8 , reviewed all of the raw data, and

6 The application rates were taken from proprietary agricultural survey data.

7 EPA adjusted EECs for clear water and turbid water by using different rates of photolysis.

8 The cucumber is the most sensitive species in the vegetative vigor study for sulfentrazone.14 recalculated the 25% Inhi bition Concentration (IC 25 ) value using current statistical models. The

new cucumber IC 25 value is 0.0016 lbs a.i./A. Previously, EPA used an IC 25 of 0.00052 lbs a.i./A from the cucumber study to calcu late terrestrial plant RQs and buffer distances for dicots. EPA recalculated risk quotients (RQs) for dicots using the cucumber endpoint to determine the

reasonable worst case risk to non-ta rget broadleaf plants. Revised RQs for a range of application rates, bracketing both labeled rate s and use rates from agricultur al survey data, range from 0.19 to 17.39 for both ground and aerial ap plication of sulfentrazone. Please see the June 9, 2015

memo, Addendum to the Environmental Fate and Ecol ogical Risk Assessment for Sulfentrazone Registration Review, for additional details.

Revised Spray Drift Analysis. EPA ran th e Ag-Drift model using the new cucumber endpoint to calculate eff ects distances for sulfentr azone. The effects distan ce is the off-field area of potential adverse effects to non-target plants. Beyond this di stances, there would be low potential to adversely affect non- target plants. The revised Ag-D rift runs provide the effects distances at a range of applic ation rates, for both ground and aer ial application, for different boom heights and droplet sizes. For ground application of sulfen trazone, low boom, and fine to medium coarse droplets, the effects distance ranged from 40 to 105 feet for agricultural crops. For aerial application, using an application he ight 10 feet above the crop canopy, the effects distance ranged from 220 to 640 feet for coarse to very coarse droplets and 335 to >1000 feet for medium to coarse droplets.

2. Ecological Incidents

Between 2002 and 2005, EPA received reports of 19 incidents involving injury to nontarget plants associated with herbicide products containing su lfentrazone. Most of these incidents were the result of lega l registered use of herbicides containing sulfentrazone, although some of the products contained more than one he rbicide active ingredient . A total of 7,707 acres were affected. According to the last search of EPA’s environmen tal incident database performed on June 1, 2015, no incidents have been reported since 2005. However, a lack of reports does not necessarily mean that there were no incidents.

3. Characterization of Ecological Risk

The preliminary risk assessment and risk assessment addendum for sulfentrazone identified some RQs that exceeded EPA’s leve l of concern (LOC) for nonlisted species. The Agency uses the LOC as an indicator of potentia l adverse effects to nonta rget organisms. LOC exceedances are only one line of evidence used by EP A to describe the risks posed by a pesticide to nontarget organisms. This risk characterization sect ion describes other lines of evidence for sulfentrazone, and puts the LOC exceed ances into a broader context.

Birds. For sulfentrazone, although the chronic RQ s for birds exceed the LOC, EPA does not expect risk to birds for the following reasons. RQ exceedances were seen for birds eating a diet of arthropods or short grass, exposed to sulf entrazone at a rate of 0.3 lb a.i./A, with RQs of 2.8 and 7.2, respectively. In addition, the avian RQs are based on a NOAEC from an avian reproductive toxicity study in the bobwhite quail, which showed an 8% reduction in body weight of 14 day old hatchlings at the NOAEC, relative to the control group. No adverse effects were seen in an avian reproductive study in the mallard duck. In addition, sulfentrazone was15 practically nontoxic in acut e oral and subacute dietary toxicity studies in birds. Thus, EPA has a

low level of concern and does not expect sulfentrazone to pos e chronic risks to birds.

Aquatic Invertebrates. Although the preliminary risk as sessment for sulfentrazone indicated chronic RQs of concern for estuarin e/marine invertebrates, the Agency has low confidence in these RQ values. These RQs are based on both the worst-case exposure scenario and a chronic NOAEC with high uncertainty. The mysid NOAEC of 0.003 mg a.i./L is based on

an acute-to-chronic ratio because EPA has no chr onic toxicity data for the mysid shrimp. There is inherent uncertainty in the use of an acute -to-chronic ratio because it represents an unbounded measure of risk. Therefore, EPA does not expe ct risks to estuarine/marine invertebrates

associated with use of sulfentrazone.

Terrestrial Plants . The RQs for nontarget terrestri al plants range from 0.19 to 17.9 following exposure to sulfentrazone at both labele d rates and actual use rates. These RQs are based on the vegetative vigor endpoint for cucumber (the most sensitive species), which is within the same order of magnitude of the IC 25 for soybean. These data indicate that sulfentrazone can harm nontarget plants exposed dur ing the vegetative growth ph ase. However, the timing of sulfentrazone application may partially mitig ate adverse effects to nontarget plants. Sulfentrazone is most typically applied in early spring or late fall. In addition, available usage data show that sulfentrazone is typically applied at rates below the maximum labelled application rate, resulting in lower exposure and ri sk than indicated by the RQs.

Although the modeled spray drift effects dist ances for sulfentrazone are as high as 105 feet from edge of field for ground applicati on and >1000 feet for aeria l application at the maximum labeled application ra te, these calculated effects distances are proportional to application rate. Sulfentrazone is seldom applied at the maximu m label rate. Effects distances do not consider many of the drift reduction meas ures on current sulfentrazone product labels due to model limitations. Furthermore, aerial application of sulfentrazone is limited to three crops; of these, sulfentrazone is aerially ap plied to 2% of all s oybeans and 5% of all sunflowers grown in the US. Application to sugarcane is limited to two states in accordance with FIFRA 24(c) special local need registrations. To address concer ns for off-target spray drift, especially from aerial application, EPA is requiring various mitigati on measures to reduce drift. FMC, the lead technical registrant for sulfentrazone, has ag reed to these drift re duction measures.

See the April 4, 2015 memo, Sulfentrazone Usage Information , and the June 9, 2015

memo, Addendum to the Environmental Fate and Ecol ogical Risk Assessment for Sulfentrazone Registration Review, for details.

C. Benefits Assessment

Sulfentrazone has been shown to provide cost -effective weed control in several field and row crops including corn, dry beans and peas, soybean s, sunflowers, and tobacco. It is used in certain crops to control weeds th at are resistant to glyphosate or sulfonylurea herbicides, such as Palmer amaranth and kochia. The major bene fits of sulfentrazone are summarized below; additional details may be found in the June 4, 2015 memo, Sulfentrazone Qualitative Benefits

Assessment

.16 Corn. Sulfentrazone is applied to corn at an average application rate of 0.06 lb/A to approximately 28,700 total acres annually, or le ss than one percent of the corn crop. Although sulfentrazone is only applied to a limited number of acres, EPA considered this crop in the qualitative benefits analysis because of the overa ll importance of this crop in U.S. agriculture.

S ulfentrazone is recommended for the control of a number of difficult to control weeds such as common waterhemp, giant ragweed, and marestail. Overall, sulfentrazone controls several difficult to control weeds and is slightly less expe nsive than several of the competing herbicides.

Dry beans/peas. Sulfentrazone is applied at an aver age application rate of 0.09 lb/A to approximately 415,000 total acres annually, or 15% of the total crop of dry beans and peas grown in the US. S ulfentrazone is used in North and S outh Dakota for the control of acetolactate synthase (ALS) 9 herbicide-resistant kochia, an emerging problem weed, where it provides 6 to 8 weeks of residual control. According to EPA Pr oprietary Data (2009-2013), sulfentrazone is the

second most used herbicide for the control of kochia and other resistant weeds. In dry beans/peas, sulfentrazone effectively controls ALS -resistant kochia and is comparable in price to

available herbicides.

Soybeans. Sulfentrazone is applied at an average application rate of 0.15 lb/A to over 3 million acres of soybeans annually, or 5% of the soybean crop. In soybeans, sulfentrazone is recommended as part of a resi stance management program for control of glyphosate-resistant Palmer amaranth, which can cause extensive crop loss. Of the herbicides used to control Palmer amaranth on soybeans, on average, sulfentrazone was the sixth most used active ingredient and accounted for 9% of total acre applications. Su lfentrazone is applied aer ially to 2% of total soybean acres nationally. In soybeans, sulfentrazone effec tively controls glyphosate-resistant Palmer amaranth and is comparable in price to other available herbicides.

Sunflower. Sulfentrazone is applied at an average application rate of 0.11 lb/A to over 1.2 million acres annually, or 50% of the sunflo wer crop. In terms of percent crop treated, sulfentrazone appears to be an important ch emical control in s unflower production. In sunflowers, sulfentrazone is recommended in Mo ntana for control of AL S-resistant kochia, a

difficult to control weed. Across the United Stat es, sulfentrazone is the most used active ingredient for controllin g kochia on sunflowers. Sulfentrazone is applied aerially to 5% of sunflower fields, effectively controls ALS-resist ant kochia on sunflowers, and is comparable in price to other availa ble herbicides.

Tobacco. Sulfentrazone is applied at an averag e application rate of 0.18 lb/A to 174,000 acres annually, or 45% of the tob acco crop, and appears to be an important chemical control for tobacco production. For tobacco grown in North Carolina sulfentrazone is one of the few herbicides recommended for control of yellow nut sedge, an aggressive and difficult to control perennial weed. According to proprietary data, sulfentrazo ne is primarily used against morning glory, redroot pigweed, and nutsedge species. In tobacco, sulfentrazone effectively controls yellow nutsedge and is comparable in price to available herbicides.

Please see the April 6, 2015 memo, Sulfentrazone Usage Information, and the June 4, 2015 memo, Sulfentrazone Qualitative Benefits Assessment , for details.

9 Herbicide group number 2, sulfonylureas.17 D. Endangered Species Assessment

In November 2013, the EPA, along with the Se rvices and the USDA, released a summary of their joint Interim Approaches for assessing risk s to endangered and threatened (listed) species from pesticides. The Interim Approaches 10 were developed jointly by the agencies in response to the National Academy of Sciences’ (NAS) recomm endations and reflect a common approach to risk assessment shared by the agencies as a way of addressing scientific differences between the EPA and the Services. The NAS report 11 outlines recommendations on specific scientific and

technical issues related to th e development of pesticide risk assessments that EPA and the

Services must conduct in conn ection with their obligations under the ESA and FIFRA.

The joint Interim Approaches were released prior to a stakeholder workshop held on November 15, 2013. In addition, the EPA presen ted the joint Interim Approaches at the December 2013 Pesticide Program Dialogue Co mmittee (PPDC) and State-FIFRA Issues Research and Evaluation Group (SFIREG) meetings. The agenci es also held stakeholder workshops - in April and October 2014, and in April 2015 - allowing additional opportunities for stakeholders to comment on the Interim Appro aches. Additional workshops are planned to enhance stakeholder involvement. As part of a phased, iterative process for developing the Interim Approaches, the agencies will also c onsider public comments on the Interim Approaches in connection with the development of upcoming Registration Review decisions. The details of the joint Interim Approaches ar e contained in the white paper Interim Approaches for NationalLevel Pesticide Endangered Speci es Act (ESA) Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report 12 , dated November 1, 2013.

Given that the agencies are continuing to de velop and work toward implementation of the Interim Approaches to assess the potential risk s of pesticides to listed species and their designated critical habitat, th e ecological risk assessment s upporting this Interim Decision for Sulfentrazone does not contain a complete ESA anal ysis that includes eff ects determinations for specific listed species or designate d critical habitat. Although EP A has not yet completed effects determinations for specific species or habita ts, for this interim d ecision, EPA’s evaluation assumed, for all taxa of non-target wildlife and plants, that listed species and designated critical habitats may be present in the vicinity of th e application of sulfentr azone. This assessment

allows EPA to focus its future evaluations on the types of species where the potential for effects exists once the scientific methods being develope d by the agencies have been fully vetted. When the Agencies have fully developed a nd implemented the scientific methodology for evaluating risks for listed species and their designated critical habitats, these methods will be applied to subsequent analyses for sulfentrazone as part of completing the final registration

review decision.

10 Interim Approaches for National-Level Pesticide Endangered Species Ac t (ESA) Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report. Available at http://www2.epa.gov/endangered-species /interim-approaches-pesticide-endang ered-species-act-assessments-basednas-report

11 Assessing Risks to Endangered and Th reatened Species from Pesticides . National Academy of Sciences. 1983.

Available from http://www.nap.edu/catalog.php?record_id=18344

12 Available at http://www.epa.gov/espp/2013/nas.html18 E. Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA review s numerous studies to assess potential adverse outcomes from exposure to chemicals. Collectively, these studies include acute,

subchronic and chronic toxici ty, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or syst emic toxicity. These studies include endpoints which may be susceptible to endocrine influenc e, including effects on endocrine target organ histopathology, organ weights, es trus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard asse ssments, EPA evaluates

acute tests and chronic studies that assess growth, developmen tal and reproductive effects in different taxonomic groups. As part of its mo st recent registration decision for sulfentrazone,

EPA reviewed these data and selected the most sensitive endpoints for re levant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), sulfentrazone is subject to the endocrine screening part of th e Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingredie nts) may have an effect in hu mans or wildlife similar to an effect produced by a “naturally occurring estr ogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two-tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact w ith the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal sy stems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Ti er 2 tests are necessary based on the available data. Tier 2 testing is designe d to identify any adverse endocr ine-related effects caused by the substance, and establish a dose-re sponse relationship between the dos e and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, which contains 58 pest icide active ingredients and 9 inert ingredients. A second list of

chemicals identified for EDSP scr eening was published on June 14, 2013 13 and includes some pesticides scheduled for Regist ration Review and chemicals found in water. Neither of these

lists should be construed as a list of known or likely endocri ne disruptors. For further information on the status of the EDSP, the policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit EPA’s EDSP website. 14

In this interim decision, EPA is making no human health or environmental safety findings associated with the EDSP screening of sulfen trazone. Before completing this Registration Review, the Agency will make an EDSP FFDCA section 408(p) determination.

13 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of

chemicals.

14 http://www.epa.gov/endo/19 

### IV. INTERIM REGISTRATI ON REVIEW DECISION

A. Risk Mitigation and Regulatory Rationale

1. Occupational Exposure

To address risk concerns associated with occupational exposure, pesticide handlers who are mixing and loading dry flowable and liquid formulations of sulfentrazone must wear chemical-resistant gloves. Most, but not all, sulfentrazone dry flowable and liquid product labels currently require either waterproof or chemical-resistant gloves. Therefore, certain product registrations need to be amended to require use of chemical-resistant gloves. FMC, the lead sulfentrazone registrant, has agre ed to this label amendment.

The re-entry interval (REI) fo r sulfentrazone is 12 hours, based on the acute toxicity of this herbicide (Category III). This re-entry interval is established in accordance with 40 CFR § 156.208c(2)(iii). This REI applies to all pesticid e products containing sulfentrazone that do not also contain another pesticide active ingredient wi th a more restrictive (longer) REI. Therefore, certain product registrations need to be amended to require a 12 hour REI.

2. Environmental Effects

As discussed in the Ecological Risk Assessmen t section of this document, sulfentrazone has been determined to pose a potential risk c oncern for nontarget terrestri al plants, especially dicot species. In addition, ther e is a lack of consistency am ong sulfentrazone product labels regarding mitigation measures to minimize nontarget effects from spray drift. To address these concerns, the Agency is requiri ng label changes for sulfentrazone technical and agricultural enduse products to reduce off-target spray drift. EPA’ s intention is to establish a baseline level of protection against spray drift that is consistent across all sulfentrazone products registered for use in agricultural, wide area, or rights-of-way settin gs. The following label re strictions are required for all sulfentrazone technical grade produc ts and all agricultur al end-use products:

 Use of spray nozzles limiting product droplet size during applications to medium or coarse in

accordance with the American So ciety of Agricultural and Biological Engineering (ASABE) standard S-572;

 For boom spraying, the minimum release height must be 30 inches from the soil for ground applications and 10 feet from the top of th e crop canopy for aerial applications (unless a greater application height is required for pilot safety);

 Applicators may spray only when wi nd speed is between 3 and 10 mph;

 Aerial application is allowed only when local environmental conditions 15 prohibit ground application;

15 Aerial application will be allowed when the field is too wet to safely apply pesticides using ground equipment.20  When aerial application is allowed, the minimum finished spray volume is 5 gallons per acre;

and

 For ground application, the minimum finished sp ray volume is 10 gallons per acre for preemergence use and 15 gallons per acre for use in a tank mix with one or more contact, burndown herbicides.

All registrants who have sulfentrazone techni cal grade or agricultural end-use products are subject to these requirements and must amend their labels accordingly.

3. Herbicide Resistance

To prevent the development of resistance to sulfentrazone among common weeds, the Agency is requiring that all herbicide products containing sulfentrazone (except for those registered solely for homeowner use) c ontain resistance-management labeling. These specifications follow the recommendations of th e Weed Science Society of America publication, Reducing the Risks of Herbicide Resi stance, Best Management Practices and

Recommendations 16

. The Agency first provided guidance on resistance management labeling in Pesticide Registration (PR) Notice 2001-5, Guidance for Pesticide Registrants on Resistance Management Labeling. EPA is requiring the following he rbicide-resistance labeling for

sulfentrazone:

 Mandatory listing of herbicide mechanism of action, and the Weed Science Society of America herbicide group number, at the top of the first page of each product label;

 Instructions to alternate use of products containing sulfentr azone with other herbicides with different mechanisms of action;

 Recommendations to scout for weeds before and after sulfentrazone application, to ensure proper identificati on of weeds and growth stag e and to confirm product performance; and

 Instructions to report herbicid e failure to local extensions specialists, certified crop advisors, and/or sulfen trazone registrants.

EPA believes that the inclusion of herb icide-resistance management language on sulfentrazone labels is important to slowing the development of resi stance to this herbicide while maintaining flexibility for growers. Weed resist ance is a complex issue and registrants play an important role in ensuring effective resistance management. Educating all stakeholders about managing herbicide-resistance is impor tant, and the product label is a cr itical part of this effort.

B. Tolerance Amendments

The Agency has determined that there are no adverse human health effects from use of sulfentrazone, and that the sulfentrazone tole rances established in 40 CFR § 180.498 continue to meet the safety standard of FFDCA. However, so me changes to the sulfentrazone tolerances are necessary to correct commodity definitions, upda te crop group tolerances , and correct tolerance

16 Norsworthy et al. 2012. Weed Science 2012. Special Issue: 31-62.21 values for indirect or inadvert ent residues. Therefore, EPA is pursuing the following changes to

the sulfentrazone tolerances listed in 40 CFR § 180.498:

 The tolerance for “ Flax ” (at 0.15 ppm) will be changed to “ Flax, seed ” to correct the commodity definition. The tolerance le vel remains unchanged at 0.15 ppm.

 The tolerance for “ Nut, tree, group 14 ” will be updated to “ Nut, tree, group 14-12 .” The tolerance level remains unchanged at 0.15 ppm.

 The tolerance for “ Pistachio ” will be revoked concomitant with the revision of the tolerance

for tree nuts to in clude pistachio.

 The tolerances for indirect or inadvertent residues of sulfen trazone established in 40 CFR § 180.498(d) will be corrected to thr ee significant figures, in accordan ce with current policy.

EPA will conduct rulemaking to implement these to lerance changes, in accordance with FFDCA.

C. Endangered Species

As previously mentioned, EPA is current ly working with the Services and other stakeholders to implement an interim approach fo r assessing potential risk to listed species and their designated critical habitats in accordance with the ESA. When the Agencies have fully developed and implemented the scientific met hodology for evaluating risks for listed species and their designated critical habitats, these methods will be applied to subsequent analyses for sulfentrazone as part of completing th e final registration review decision.

D. Interim Registration Review Decision

In accordance with 40 CFR Sections 155.56 and 155.58, the Agency is issuing this Interim Registration Review Decision. Except fo r the EDSP, pollinator, and ESA components of this case, the Agency has made the following Inte rim Registration Review Decision: (1) with the possible exception of pollinator st udies listed in Section IIIB of this document, no additional data are required at this time; and (2 ) changes to the affected registrations and their labeling are necessary at this time.

In this Interim Registration Review D ecision, EPA is making no human health or environmental safety findings associated with the EDSP screening of sulfentrazone, nor is it making a complete endangered species finding or a complete assessment for effects to pollinators. The Agency’s final registration review decision for sulfentrazone will depend upon

the result of an ESA Section 7 consultation with the Services, an EDSP FFDCA section 408(p) determination, and an assessment of non-target exposure to pollinators.

E. Data Requirements

At this time, with the possible exception of pol linator studies listed in Section IIIB of this document, no additional data are required as part of this Interim Regist ration Review Decision. Although the Proposed Interim Decision mentioned th e need for additional analytical reference standards to replenish supplies, these were subsequently submitted to the EPA analytical chemistry lab in Fort Meade, MD, and are no longer needed.22 

### V. NEXT STEPS AND TIMELINE

A. Interim Registration Review Decision

In accordance with 40 CFR Sections 155.56 and 155.58, the Agency is issuing this Interim Registration Review Decision docum ent for sulfentrazone. Except for the EDSP, pollinator, and ESA components of this registra tion review case, EPA has made the following Interim Registration Review Decision for sulf entrazone: (1) with th e possible exception of pollinator studies listed in Section IIIB of this document, no additional data are needed at this time, and (2) changes to affected sulfentraz one product registrations and product labeling are necessary at this time. These changes will incorp orate the mitigation measures described in this document into the terms and conditions of regi stration and be implemented through amendment

of the affected labels.

In this Interim Registration Review Decisi on, the Agency is maki ng no human health or environmental safety findings associated with the EDSP screening of sulfentrazone, nor is it making a complete endangered species finding or a complete assessment for effects to pollinators. EPA’s final registration review decision for sulfentrazone will depend upon the

results of an ESA Section 7 Consultation with the Services, an ED SP FFDCA Section 408(p) determination, and an assessment of non-target exposure to pollinators.

B. Implementation of Mitigation Measures

All sulfentrazone technical registrants and al l end-use registrants of agricultural products containing sulfentrazone must submit amende d labels, which implement the label changes summarized in Appendix A, to EPA within 90 da ys of issuance of this Interim Registration

Review Decision for sulfentrazone.23 Appendix A: SULFENTRAZONE Label Table

Summary of Labeling Changes for Sulfentrazone

Description Amended Labeling Language for Sulfentrazone Products Placement on Label

Technical and Manufacturing Use Products

Use Limitations “Only for formulation into a/n [insert pesticide class] for the following use(s) [list only those uses and application methods that are being supported by technical and MP registrant ].” Directions for Use

Products Labeled for Agricultural Use

HERBICIDE RESISTANCE MANAGEMENT

Herbicide Mode of

Action “Group 14 HERBICIDE” Front Panel, upper right quadrant, surrounded by a

black (or suitable color) rectangle

Weed Resistance

Management  Instructions to alternate use of products containing

sulfentrazone with other he rbicides with different mechanisms of action;

 Recommendations to scout for weeds before sulfentrazone application for identification and growth stage and after sulfentrazone application to look for poor performance or likely resistance;

 Instructions to report herbicide failure to local extension specialists, certified crop advisors, and/or sulfentrazone registrants. Directions for Use, prior to directions for specific crops under the heading”

WEED RESISTANCE

MANAGEMENT”

PERSONAL PROTECTIVE EQUIPMENT AND RE-ENTRY INTERVAL PPE Labeling Requirements for all agricultural end-use products containing

sulfentrazone “PERSONAL PROTECTIVE EQUIPMENT (PPE)

Applicators, mixers, loaders, and other pesticide handlers

must wear:

 Chemical-resistant gloves” Precautionary Statements section, under the heading

Hazards to Humans and

Domestic Animals “Personal Protective Equipment (PPE)”
REI Requirement

 The REI for sulfentrazone products is 12 hours, unless the acute toxicity of the product indicates the need for a longer REI. Precautionary Statementssection, under the heading “Reentry Interval”

ENVIRONMENTAL HAZARDS

Environmental Hazard

 Warning that drift and runoff of sulfentrazone products may be hazardous to plants in adjacent

areas. Environmental Hazards

SPRAY DRIFT
Spray Drift Language SprayNozzles &

Droplet Size  Select nozzles and applica tion pressure that deliver medium to coarse or larger spray droplets as

indicated in the no zzle manufacturer’s

recommendations and in accordance with ASABE*

Standard S-572.

 Select coarse to very coarse droplet size when sulfentrazone is used as a preemergent/preplant application. Directions for Use, prior to directions for specific crops under the heading “SPRAY

DRIFT”24 Summary of Labeling Changes for Sulfentrazone

Description Amended Labeling Language for Sulfentrazone Products Placement on Label

 Select medium to very coarse droplet size when sulfentrazone is used postemergence with a contact

burndown herbicide.

 Applicators may spray only when wind speed is between 3 and 10 mph.

 Do not apply as spray droplets smaller than medium to coarse (defined by the ASABE* standard). Spray Drift Language Spray Volume  Ground applicators must use a minimum finished spray volume of 10 gallons per acre.

 When sulfentrazone is tank mixed with a contact burndown herbicide, ground applicators must use a minimum spray volume of 15 gallons per acre. Directions for Use, prior to directions for specific crops under the heading “SPRAY

DRIFT”

Spray Drift Language Aerial Application  Aerial application is allowed only when environmental conditions prohibit ground application.

 For aerial applications, the maximum release height must be 10 feet from the top of the crop canopy, unless a greater application height is required for pilot safety.

 “When this product is allowed to be applied by air, applicator must use a minimum finished spray volume of 5 gallons per acre.” Directions for Use, prior to directions for specific crops under the heading “SPRAY DRIFT” “Aerial Application”

DIRECTIONS FOR USE
Language to restrict use to target species only “This product may only be used to control [insert pests and

sites ]...” Directions for Use

Under “Use Restrictions”

Maximum single and annual application rates “The maximum single application rate for [insert product name] is [ insert amount of product equivalent to the maximum application rate for each crop or crop group,] the equivalent of [insert maximum application rate in units of lb a.i./A].”

“The maximum annual application rate for [insert product name] is [ insert amount of product equivalent to the maximum annual application rate for each crop or crop group,] the equivalent of [insert maximum application rate in units of lb a.i./A].” Directions for Use for Specific Crops

Aerial Application “Aerial applicati on is allowed only when environmental conditions prohibit ground application.” Directions for Use

Under “Use Restrictions” “Aerial Application” Aerial Application “When this product is a llowed to be applied by air, applicator must use a minimum finished spray volume of 5 gallons per

acre.” Directions for Use

Under “Use Restrictions” “Aerial Application” Aerial Application  The maximum release height must be 10 feet from the top of the crop canopy, unless a greater application height is required for pilot safety.

*ASABE – American Society for Agricu ltural and Biological Engineers.