2 

### Sodium Acifluorfen Proposed Interim Decision

Table of Contents

Contents

I. INTRODUCTION................................................................................

. ...3

II. USE AND USAGE ....................................................................................5

III. SCIENTIFIC ASSE SSMENTS..................................................................

. ..5

A. Human Healt h.................................................................................

. ...5

1. Risk Concl usions........................................................................

. ...6

2. Human Inci dents........................................................................

. ....6

3. Tolerances

.............................................................................. . ... ...6

B. Ecological Risk Assessment.............................. ......................................7

1. Risk Conclu sions............................................................................7

2. Ecological Incid ents........................................................................10

3. Characterization of Ecological Risk...................................................... 10

C. Benefits Assessment...

..................... ....................................................12

D. Endangered Species A ssessment.............................................................12

E. Endocrine Disruptor Screening Program....................................................1 3

IV. PROPOSED INTERIM REGISTRAT ION REVIEW DECISION...........................14

V. NEXT STEPS AND TIMELINE..................................................................1 8 Appendix A: Summary of Actions Taken fo r Sodium acifluorfen .....................................19 Appendix B: Sodium acifluo r fen Lab el Table........................................................

. ... 193



### I. INTRODUCTION

This document is the Environmental Protection Agency’s (EPA or the Agency) Proposed Interim Registration Review Decision for sodium acifluorfen ( case 2605 , PC 114402 ) and is being issued pursuant to 40 CFR sections 155.56 and 155.58. A registration review decision is the Agency's determination whether a pesticide meets, or does not meet, the standard for registration in the
Fede ral Insecticide, Fungicide, and Rodenticide Act (FIFRA). The Agency may issue, when it determines it to be appropriate, a n I nterim R egistration R eview D ecision before completing a registration review. Among other things, the I nterim R egistration R eview D ec ision may : 1) require new risk mitigation measures ; 2) impose interim risk mitigation measures ; 3) identify data or information required to complete the review ; and 4) include schedules for submitting the required data, conducting the new risk assessment a nd completing the registration review. For
further information on sodium acifluorfen , additional documents can be found in EPA’s pub lic docket (EPA

- HQ

- OPP

- 2010

- 0135 ) at www.regulations.gov

.

FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandated the continuous review of existing pesticides. All pesticides distributed or sold in the United States generally must be registered by the EPA based on scientific 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 policies and practices change, all r egistered pesticides continue to meet the statutory standard of no unreasonable adverse effects. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review program, the Agency periodically re

- evalua tes pesticides to make sure that as these changes occur, products in the marketplace can continue to be used safely. Information on this program is provided as http://www .epa.gov/pesticide

- reevaluation/registration

- review

- process

.

In 2006, the Agency implemented the registration review program pursuant to FIFRA section 3(g) and will review each registered pesticide every 15 years to determine whether it continues to

meet the FIFRA standard for registration.

EPA is issuing a proposed interim registrat ion review decision for sodium acifluorfen 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 currently working with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service to develop methodologies for conducting national endangered species assessments for pesticides. Therefore, although EPA has not yet fully

ev aluated risks to threatened and endangered species, the Agency will complete its endangered species assessment and any necessary consultatio n with the Services for sodium acifluorfen prior to completing the sodium acifluorfen registration review. Likewise , the Agency will complete endocrine screening for sodium acifluorfen , pursuant to the Federal Food, Drug, and Cosmetic Act (FFDCA) section 408(p), before completing this registration review. Last, EPA will determine whether additional pollinator exposure and effects data are necessary to make a final registrat ion review decision for sodium acifluorfen and issue a data call

- in (DCI) to obtain any
such data prior to completing the sodium acifluorfen registration review.

Sodium acifluorfen is a selective

, d iphenyl ether herbicide and a light d ependent peroxidizing
herbicide (LDPH) registered for post

- emergent weed control on soybeans, peanuts, rice, and4

strawberries. There are currently 12 FIFRA Section 3 registrations

. All sodium acifluorfen
residential use products have either been cancelled or are undergoing cancellation

. On February 26, 2016, Bonide Products, Inc. requested the voluntary cancellation of the one remaining residential product (EPA Registration Number 4

- 433), which has been suspended for sev eral years and not marketed. The Agency expects to announce shortly the notice of receipt of this request through the Federal Register and anticipates granting the voluntary cancellation request by the end of the year. Sodium acifluorfen was first registe red in the United States in 1980 , and a
Re re gistration Eligibility Decision (RED) was issued in September of 2003. Acifluorfen is a degradate of the herbicide lactofen and is a dissociated product of sodium acifluorfen . EPA assessed lactofen (case number 7210) separately in its own registration review case and issued an
interim decision for that active ingredient in December 2014 (EPA

- HQ

- OPP

- 2005

- 0287).



### Summary of Sodium Acifluorfen Regis t ration Review

Pursuant to 40 CFR section 155.50, EPA formally init iated registration review for sodium
acifluorfen (case 2605 ). The following summary highlights significant events that have occurred during the registration review of sodium acifluorfen

. Documentation of these events can be found in EPA’s sodium acifluorfen public docket, EPA

- HQ

- OPP

- 2010

- 0135 , accessed at www.regulations.gov :

 March 24, 2010

– S odium acifluorfen Summary Document was issued for a 90

- day public comment period. The Summary Document in cluded the Preliminary W ork P lan (PWP)
and was accompanied by the scoping document and problem formulation.

 September 3, 2010

- Final Work Plan (FWP) for sodium acifluorfen was issued . The Agency received one comment during the 90

- day public comment period on the PWP. This comment did not change the risk assessment, data needs, or time line identified in
the PWP.

 October 19, 2011

– Generic Data Call

- In (GDCI) for sodium acifluorfen w a s issued.

 July 8

, 2015

– The Agency published the Preliminary Environmental Fate and Ecological Risk Assessment Endangered Species Effects Determination for Acifluorfen
and the Sodium Acifluorfen. Draft Human Health Risk Assessment for Registration
Review for a 60

- day public comment period. No comments were recei ved

.

 March, 2016

- The Agency is now publishing the Sodium Acifluorfen Proposed Interim Registration Review Decision , in docket number EPA

- HQ

- OPP

- 2010

- 0135

, for a 60

- day public comment period. In addition to this document, the Agency is publishing the following supporting documents:

o Addendum to: Registration Review: Preliminary Environmental Fate and Ecological Risk Assessment Endangered Species Effects Determination for
Acifluorfen

, March 1 , 2016.

o Sodium Acifluorfen Usage Information , March 17 , 2016.5



### II. USE AND USAGE

Sodium acifluorfen is a selective, post

- emergent contact herbicide registered for use to control
annual broadleaf weeds and some grasses in soybeans, rice, peanuts, and strawberries

. Sodium
acifluorfen is a mem b er of the d iphenyl ether group of herbicides and it belongs to a class of compounds, light dependent peroxidizing herbicides (LDPH), known to have a phototropic mode of action in plants. LDPHs act in plants through inhibiti on of the enzyme protoporphyrinogen
oxidase

, lead ing to cell m embrane disruption through reactive oxygen species in the presence of light.

Sodium acifluorfen is applied to approximately one million acres of cropland annually in the
United States. The crops that are most dependent on sodium acifluorfen in terms of average percent crop treated (PCT) include peanuts (1 7 %) and rice (5%)

. For soybeans about 1% of the crop is treated on average which accounts for about 800,000 acres of cropland treated annually
with sodium acifluorfen. B etween 2004 and 2012

, the averag e annual pounds (lbs) active ingredient (AI ) used are as follows: peanuts (50,000 lbs AI /year), rice (20,000 lbs AI /year), soybeans (80,000 lbs AI

/year), and strawberries (5 00 lbs AI /year)

. During the same time period,

on average, one application of sodium acifluorfen wa s applied per year to these registered uses

. More recently, between 2009 and 2013, 2.5% of treated peanuts, 4.6% of treated rice

, and 10% of treated soybeans, received two applications.

While aerial application is permitted for a ll lab eled crops, EPA market research data indicate that sodium acifluorfen is applied aerially to two crops only, rice and soybeans. Aerial application to rice and soybeans accounts for 10% of the total acres treated with sodium acifluorfen per year.
Mo st of the aerial applications of sodium acifluorfen are made on rice with an average of up to 83,000 acres treated annually. This accounts for approximately 70% of the acres treated aerially
with sodium acifluorfen annually from 2010

- 2014. For soybeans, aerial applications are made on about 33,000 acres treated on average, which accounts for the remaining 30% of the acres treated aerially with sodium acifluorfen annually from 2010

- 2014 (Market Research Data, 2010

- 2014). On average, 4% of the sodium acifl uorfen applied to soybeans is made aerially, while approximately 66% of the sodium acifluorfen applications to rice are made aerially. Aerial applications are made to accommodate wet or overgrown fields that are unable to be entered by foot or ground mach inery. For weed control in strawberries, sodium acifluorfen is typically applied using ground equipment as a band application during renovation (over the top of straw mulch) or after transplanting the plants (before laying plastic mulch).

See Sodium Acif

luorfen Usage Information

, dated March 17 , 2016 ; for additional detail on
sodium acifluo r fen use and usage information.



### III. SCIENTIFIC ASSESSMENTS

A. Human Health

A summary of the Agency’s human health risk assessment is presented below. The Agency used
the most recent Agency science policies and risk assessment methodologies to prepare a

qua nti tative risk assessment in support of the registration review of sodium acifluorfen

. For a
detailed discussion of the human health assessment and anticipated tolerance modifications for6

sodium acifluorfen , see Sodium Acifluorfen. Draft Human Health Risk Assessment for Registration Review dated June 17, 2015. This document is available i n the public docket EPA

HQ

- OPP

- 2010

- 0135

, which can be accessed at http://www.regulations.gov/

.

1. Risk Conclusions

EPA has no dietary risks of concern for sodium acifluorfen from exposure to residues in either food or drinking water. The Agency did not conduct a residential risk assessment because all residential products are either suspended or undergoing cancellation. In fact, there is only one residential product that is c urrently registered, EPA Reg. No. 4

- 433, but that product has been suspended and not marketed for several years. On February 26, 2016, the registrant of the suspended product, Bonide Products, Inc., requested voluntary cancellation of that product. EPA exp ects to announce the notice of receipt of this voluntary cancellation request in the Federal Register shortly, and anticipates issuing a final cancellation order for that product by the end of the year. Therefore, the aggregate exposure assessment is equiv alent to the dietary assessment and not of concern. As
acifluorfen is formed from the use of two registered herbicides, sodium acifluorfen and lactofen, the aggregate assessment considered potential exposures to acifluorfen from both of these active ingre dients. However, EPA has not made a common mechanism of toxicity finding for sodium acifluorfen and any other substance for this assessment

.
For pesticide handlers with occupational exposure to sodium acifluorfen

, EPA has found
no risks of concern . The Ag ency also evaluated exposure and risk to agricultural workers
who enter areas treated with sodium acifluorfen after application. EPA determined that postapplication exposures and risks were not of concern. In addition, EPA evaluated off target exposure of adults and children to spray drift and no risk estimates of conce rn were identified

.

2. Human Incidents

On March 26, 2015, t he Agency completed a review of sodium acifluorfen incidents in
the OPP Incident D ata System (IDS) and the Centers for Disease Control and Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) Sentinel Event Notification System for Occupational Risk

- Pesticides (SENSOR) databases. One
minor incident case was ident ified . Based on the low frequency and low severity of incident cases reported , there does not appear to be a concern at this time that would warrant further investigation

. In addition, while sodium acif luor fen is included in the Agricultural Health Study, data are not yet available from this study. The Agency will
continue to monitor the incident and epidemiology information and

, if a concern is triggered, additional analysis will be conducted.

3. Tolerances

The Agency will modify t he tolerance expression so that it appropriately covers the metabolites and degradates of sodium acifluorfen and specifies the residues to be measured for each commodity. In addition, tolerances will be modified to include the
recommended number of significant figures as indicat ed below. No Codex maximum
residue limits have been established for sodium acifluorfen. The U.S. is unable to7

harmonize its tolerance (0.1 ppm) for soybean seed with the Canadian maximum residue
limit (0.02 ppm) for this commodity as the limi t of quantit ation o f the analytical method used to measure residues is 0.1 ppm.

Table 1 : Sodium Acifluorfen Tolerances (40 CFR 180.383 ) Commodity Established Tolerance (ppm) Recommended Tolerance (ppm)
Peanut 0.1 0.10 Rice, grain 0.1 0.10 Rice, straw 0.2 0.20 Soybean, seed 0.1 0.10 Strawberry 0.05 0.05

B. Ecological Risk Assessment

A summary of the Agency’s ecological risk assessment is presented below. The Agency used the most updated Agency science policies and risk assessment methodo logies to prepare a

qua nt itative risk assessment in support of the registration review of sodium acifluorfen . For a
detailed discussion of the ecological assessment for sodium acifluorfen

, see Preliminary
Environmental Fate and Ecological Risk Ass essment Endangered Species Effects Determination for Acifluorfen

, dated June 11, 2015 , and Addendum to: Registration Review: Preliminary Environmental Fate and Ecological Risk Assessment Endangered Species Effects Determination for Acifluorfen

, March 1 , 2016

. Th ese document s are available i n the public docket EPA

- HQ

OPP

- 2010

- 0135

, which can be accessed at http://www.regulations.gov/

.

EPA is currently working with its federal partners and o ther stakeholders to implement an interim approach for assessing potential 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 ha bitats are finalized, the Agency will complete its endangered species assessment for sodium acifluorfen

. As such, the risk conclusions described below pertain to non

- listed species.

1. Risk Conclusions

Terrestrial Assessment

Mammals

– In the preliminary risk assessment for sodium acifluorfen , the Agency
identified chronic risks of concern f or mammals

, with the highest dose

- based risk quotients (RQs) associated with the strawberry use (RQ up to 3.4 )

. Using the dietary

based risk quotient method (i.e. not adju sted for body weight) , there are no chronic risks
of concern. In addition, no acute risk s of concern were identified for any labeled use patter n

.

Birds and Surrogates (Reptiles and Terrestrial Amphibians)

– The a cute dose

- based RQ (0.76) exceed s the level of concern (LOC of 0.5 ) for small birds only (and surrogates) foraging on short grass for the strawberry use

. However, there are no exceedances of the8

LOC using the dietary

- based RQ method for any size class/forage item combination

. There are chronic LOC exceedances for all use patterns for the short grass, tall grass, broadleaf plants and arth ropod forage categ ories, with RQs up to 8 for the strawberry use pattern. There are no chronic LOC exceedances for the fruit/pods/seeds forage class for any use patt ern.

Invertebrates

– The only avail able data for this taxon is an acute contact to honey bees study, which classifies sodium acifluorfen as practically non

- toxic

. P otential risk to nontarget terrestrial invertebrates will be evaluated upon receipt of additional data

.

When initially scoping the registration rev iew for sodium acifluorfen , EPA did not identify the need for any additional studies to evaluate potential effects on pollinators. However, since the issuance of the June 2014 Guidance for Assessing
Pesticide Risks to Bees [1] , EPA has begun to require these data where applicable. EPA is currently determining whether additional pollinator data are needed for active ingredients in registration review whose dockets opened prior to June 2014. For those active ingredients where EPA determines that additional pollinator exposure and effects data are necessary to help make a final registration review decision, EPA intends to issue a DCI to
obtain these data. In the near future, EPA wi ll provide further information and gui dance
on this effort.

For sodium acifluorofen, t he acute contact toxicity study with adult honey bees (guideline
#850.3010 ) study has already been submitted

. Additional pollinator studies that could be required in the future are listed in Table 2 below. The Agency will require data it believes are necessary to help inform the pollinator risk assessment.

Table 2

. Potential Pollinator Data Requirements

Guideline # Study

850.3030* Honey bee toxicity of residues on foliage

850.3040** Field testing for pollinators

Non

- Guideline* (OECD 213) Honey bee adult acute oral toxicity

Non

- Guideline* (OECD 237) Honey bee larvae acute oral toxicity

Non

- Guideline* Honey bee adult chronic oral toxicity

Non

- Guideline* Honey bee larvae chronic oral toxicity

Non

- Guideline** Residues in pollen and nectar/field residue analysis

Non

- Guideline** (OECD 75) Semi

- field testing for pollinators (tunnel or colony feeding studies)

*Tier 1 (Laboratory

- based 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.

[1] http://www2.epa.gov/sites/production/files/2014

- 06/documents/pollinator_risk_assessment_guidance_06_19_14.pdf9

Plants

– As expected with an herbicide, effects on biomass and stand height were observed in terrestrial plant studies. The vegetative vigor exposure route (foliar spray)
and life stage is generally more sensitive to sodium acifluorfen than the seedling

emergence exposure route (s oil exposure) and life stage, based on the available studies. Sensitivity varies by species, with non

- grasses generally more sensitive than grasse s. A ll labeled uses of sodium acifluorfen pose potential risks of concern to non

- target terrestrial plants w hen applied aerially

. Non

- target plants may also be at risk from runoff and drainage from fields. The Addendum to the preliminary ecological assessment corrects the rates used in the TerrPlant model and presents revised RQs that are rou ghly half of
the or iginal RQ s (aerial dr ift RQ for non

- grass species dropped from 9.9 to 4.9). LOCs are exceeded for three out of the ten plant species tested, which are intended to be representative of the non

- target terrestrial plants species potentially exposed

. When

so dium acifluorfen is applied using ground equipment, spray drift RQs are below the
LOC.

Aquatic Assessment

Several studies have documented enhanced toxicity of LDPHs to fish in the presence of
ultra

- violet ( UV ) light as compared to the toxicity observed under standard laboratory lighting. Given that aquatic organisms may be exposed simultaneously to LDPH s and
UV light in natural settings, concerns have been raised that guideline chronic exposure laboratory tests may underestimate the to xicity of LDPH s in the field

. T he Agency is applying an interim adjustment factor of 29X to the no observed adverse effect concentration (NOAEC) values from standard chronic fish studies to account for the potential enhanced toxicity of LDPH chemicals und er natural sunlight. This enhanced sensitivity to LDPHs is not necessarily limited to fish and could be observed in other taxa such as aquatic invertebrates, birds, and mammals . H owever, the Agency is only applying an adjustment factor to fish at this tim e. The Agency is currently working to finalize its approach based on special fish studies required by EPA and submitted by the LDPH Task
Force.

As noted in the sodium acifluorfen preliminary ecological risk assessment, c hronic exposure RQs for freshwater fish were calculated with both the endpoin t derived from the guideline fish early life stage study (standard laboratory lighting) and with the 29X adjustment factor applied (enhanced UV lighting ) . RQ s for fish that may not receive simultaneous exposure to sodium acifluorfen and enhanced UV light are below the Agency’s LOC . RQs for fish with the LPDH adjustment factor applied exceed the LOC by up to 6

- fold for the rice use only

. The risk conclusions for freshwater fish also apply to amphibians in aquatic habitat s

.
Potential chronic risk to estuarine/marine fish cannot be quantified because of lack of definitive data. Although a chronic toxicity study with the fathead minnow is available, it
cannot b e used to calculate an acute to chronic ratio (ACR), and thereby an estimation of risk, as there were no effects at the highest dose tested. However, given that the acute endpoint for sheepshead minnow is greater than that for the rainbow trout, chronic RQ s for estuarine/marine fish would be expected to be lower than those for freshwater fish.10

Based on the available exposure data, acute risk to fish (freshwater and estuarine/marine)

, aquatic invertebrates , and aquatic plants is not exp ected

. There are no chronic data
available for freshwater invertebrates . However, chronic effects can be estimated using an acute to chronic ratio from the mysid endpoint ( the estuarine/marine acute endpoint is two orders of magnitude lower than the acute daphnid endpoint )

. Based on the mysid endpoint, there are no exceedances for chronic exposure except for the rice use pattern, with the highest RQ = 1.3. The assessment of chronic risk for aquatic invertebrates is based on guideline data conducted with standard lighting. It is not clear whether
invertebrates would experience similar enhanced toxicity from the simultaneous exposure
to sodium acifluorfen and enhanced UV light

, as chronic fish studies have demonstrated.

2. Ecological Incidents

In April 2015, the Agency reviewed the Ecological Incident Information System (EIIS) database for incidents involving sodium acifluorfen and the acifluorfen degr a date and identified one fish incident report that was classified as unlikely. The A gency also reviewed
the Avian Inciden t Monitoring System (AIMS) in April 2015 , where no sodium acifluorfen
incidents were identified . Pesticide registrants also report certain types of incidents to the Agency as aggregate counts of incidents per product per quarter. There we re 43 aggregate pl ant incidents reported for acifluorfen between 1995 and 2003. For additional details on the ecological incidents for sodium acifluorfen , see Preliminary Environmental Fate and Ecological Risk Assessment Endangered Species Effects Determination for Acifluor fen dated
June 11

, 2015

.

3. Characterization of Ecological Risk

The preliminary risk assessment a nd risk assessment addendum for sodium acifluorfen
identified some risk s that exceeded EPA’s LOC for non

- listed species. The Agency uses the
LOC as an indicator of potential adverse effects to non

- target organisms. LOC exceedances are only one line of evidence used by EPA to describe the risks posed by a pesticide to non

t arget organisms. This risk characterization section is an attempt to describe other lin es o f
evidence for sodium acifluorfen , and put the LOC exceedances into a broader context.

Mammals

– While the LOC is exceeded for chronic risk to mammals, EPA does not expect risk to mammals based on the following lines of evidence. The greatest LOC exceedance ( dose

- based RQ of 3.4) is for small mammals feeding exclusively on short

grass in treated strawberry fields receiving two applications at the maxi mum label rate of
0.375 lbs AI per acre (A). Risks would be lower with one application, which appe ars to be more typical than two applications based on available usage data. Modeled estimates assume that 100% of an exposed mammal’s diet is derived from treated food items and that the treated items contain maximum expected residues. In addition, t here are no exceedances of the LOC when considering dietary

- based RQs

. B ased on available usage data, less than 1% of strawberries are treated with s odium acifluorfen, thus any adv erse impacts to mammals is expected to be limited in scale , and unlikely

.

Birds

– While the LOC is exce eded for both acute and chronic risk to birds

, EPA does not expect risk to birds based on the following lines of evidence. For acute risk, the LOC11

(0.5) is only exceeded for small birds feeding on short grass in strawberry fields when using acute dose

- based RQs (RQ of 0.76). There are no exceedances of the acute LOC when considering dietary

- based RQs

. For chronic risk, the greatest LOC exceedance (RQ of 7.8) is for small mammals feeding exclusively on short grass in treated strawberry fields receiving two applications at the maximum label rate of 0.375 lbs AI/A. Risks would be lower with one applic ation, which appears to be typical based on available

usa ge data. Modeled estimates assume that 100% of an exposed bird’s diet is derived
from treated food items and that the treated items contain upper

- bound expected residues

, which may be conservative assumptions

. In addition, based on available usage data, l ess than 1% of strawberries are treated with sodium acifluorfen , thus any adv erse impact to birds is expected to be limited in scale

.

Fish

– Chronic RQs for fish that do not receive simultaneous exposure to sodium
acifluorfen and enhanced ultraviolet ( U V ) light are below the Agency’s LOC. Chronic RQs for fish with the LPDH adjustment factor applied exceed the LOC by up to 6

- fold for the rice use only. While the LOC is exceeded for chronic risk to fish for the rice use
under enhanced U V light , EPA does not expect widespread risk to fish based on the following lines of evidence. Not all fish would be expected to be exposed to both sodium
acifluorfen and high UV light at the same tim e. It would seem reasonable to assume that fish inhabiting shallow, clear wat er bodies would be more susceptible to chronic effects than those in deeper, more turbid water bodies. Also, fish inhabiting water bodies at lower elevations or higher latitudes may also be less likely to exhibit chronic effects due

to UV

- enhanced toxicity. At higher latitudes, the sun is lower in the sky, so UV light must travel a greater distance through ozone

- rich portions of the atmosphere, and therefore expose those latitudes to less UV radiation. Alternately, UV intensity decreases

w ith lower elevation because there is more atmosphere to absorb UV rays. The Agency also realizes many other factors can impact the amount of UV light, such as time of day, time of year, stratospheric ozone and weather (cloud cover). Given the complexity o f simultaneous exposure to sodium acifluorfen and enhanced UV light, the Agency has not yet determined the need to mitigate the potential risks of concern to fish and, if one were to mitigate, what measures might address the concern

.

Terrestrial Plants

- When using ground equipment, spray drift RQs do not exce ed the
LOC for non

- target terres trial plants. Wh en aerial application is modeled , a ll labeled
uses of sodium acifluorfen pose potential risks of concern to non

- target terrestrial plants

. The Agency’s principal concern is off

- target spray drift resulting from aerial applications.
The Addendum to the preliminary ecological assessment corrects the rates used in the TerrPlant model and presents revised RQs that are roughly half of the original nu mber ( revised aerial spray drift RQ for non

- grass species is 4.9). In addition, t he Addendum presents revised AgDRIFT modeling to reflect the current droplet size spectrum on labels ( medium to coarse droplet size)

. Effects distances were significantly re duced using medium to coarse droplet size. However, to further address concern of spray drift impact

to non

- target plants, the sodium acifluorfen registrants have agreed to various label changes designed to reduce off

- target spray drift

.

Listed Species

- Although the Agency is not making a complete listed species finding at
this time and the risk conclusions described in this documen t pertain to non

- listed12

species, the proposed lab el changes to address concern for and reduce spray drift impact

to non

- ta rget (non

- listed) terrestrial plants are also expected to reduce the extent of exposure and may reduce ri sk to the following listed taxa whose range and/or critical
habitat co

- occur with the use of sodium acifluorfen : terrestrial, semi

- aquatic and aquatic plants; terrestrial invertebrates; birds; terrestrial and aquatic

- phase amphibians; reptiles; mammals; freshwater and marine/estuarine fish and invertebrates.

EPA has not yet fully eva luated risks to listed species at this time. The Age ncy will complete its listed species assessment and any necessary consultation with the Services
for sodium acifluorfen prior to completing the sodium acifluorfen registration review.

C

. Benefits Assessment

Sodium acifluorfen is registered for use for selective control of broadleaf species and certain grass species in rice, soybeans, peanuts, and strawberries. In evaluating potential risk mitigation for sodium acifluorfen, EPA considered the risks, the benefits, and the use pattern of this

compoun d. EPA believes that there may be potential risk to non

- target plants from the use of
sodium acif

luorfen. However, these risks are outweighed by the benefits associated with use of this compound. About one million acres are treated annually with sodium aci fluorfen. Approximately 1 7 % of peanut acres and 5% of rice acres , on average, are treated with sodium acifluorfen, indicating that it is an important tool for controlling weeds in these crops. For soybeans about 1% of the crop is treated on average annual ly

, which accounts for about 800,000
acres of the one million acres treated annually with sodium acifluorfen. For strawberries, whi le overall usage is relatively low (<500 lbs AI used on average per year), sodium acifluorfen may be an important component of an h erbicide program for some small

- acreage producers who do not fumigate their strawberry beds

. Minor strawberry producers who do not use fumigation may
use herbicides such as sodium acifluorfen for weed control. EPA has limited data to confirm

actua l usage on strawberries. EPA market research data , however, do not show usage of sodium
acifluorfen on strawberries in the major strawberry producing stat es of California and Florida

.

Sodium acifluorfen is reported to be an important alternate mechanism of action (MOA) for crops with species of weeds resistant to other common herbicides such as glyphosate and ALS

inhibitor herbicides 1

.
For additional detail on the qualitative benefits of sodium acifluorfen, see Sodium Aciflu orfen Usage Information, March 17 , 2016

.

D

. Endangered Species Assessment

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

1 Available at http://www.gaweed.com/slides/PAC

- 08/PAC

- 08.pdf13

EPA and the Services. The NAS report 2 outlines r ecommendations on specific scientific and technical issues related to the development of pesticide risk assessments that EPA and the Services must conduct in connection with their obligations under the ESA and FIFRA.

The joint Interim Approaches were rel eased prior to a stakeholder workshop held on November 15, 2013. In addition, the EPA presented the joint Interim Approaches at the December 2013 Pesticide Program Dialogue Committee (PPDC) and State

- FIFRA Issues Research and Evaluation Group (SFIREG) meet ings. The agencies also held stakeholder workshops

— in April and October 2014, and in April 2015

— allowing additional opportunities for stakeholders to comment on the Interim Approaches. Additional workshops are planned to enhance stakeholder
involvement. As part of a phased, iterative process for developing the Interim Approaches, the agencies will also consider public comments on the Interim Approaches in connection with the development of upcoming Registration Review decisions. The details of the joint Interim Approaches are contained in the white paper Interim Approaches for National

- Level Pesticide Endangered Species Act (ESA) Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report 3 , dated November 1, 2013.

Give n that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, the ecological risk assessment supporting this Propo sed I nterim
Decision for sodium acifluorfen does not contain a complete ESA analysis that includes effects determinations for specific listed species or designated critical habitat. Although EPA has not yet completed effects determinations for specific spe cies or habitats, for this preliminary assessment 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 vicinit y of the application of sodium
acifluorfen . This a ssessment will allow EPA to focus its future evaluations on the types of species where the potential for effects exists once the scientific methods being developed by the agencies have been fully vetted. Once the agencies have fully developed and implement ed the scientific methodology for evaluating risks for listed species and their designated critical habitats, these methods will be applied to subsequent analyses for sodium acifluorfen as part of completing t his registration review.

E

. Endocrine Disrupt or Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ weights, estru s cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in diff erent taxonomic groups. As part of its most recent registration decision for sodium acifluorfen , EPA

2 Assessing Risks to Endangered and Threatened Species from Pesticides. Available at http://www.nap.edu/catalog.php?record_id=18344

3 Available at http://www2.epa.gov/endangered

- species/assessing

- pesticides

- under

- endangered

- species

- act#report14

reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as requi red by FFDCA section 408(p),
sodium acifluorfen is subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingre dients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statutorily requir ed determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with 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 systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identif y any adverse endocrine

- related effects caused by the substance, and
establish a dose

- response relationship between the dose 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 pesticide active ingredients and 9 inert ingredients. A second list of chemicals identified for EDSP screening was published on June 14, 2013 4 and includes some pesticides scheduled for Registration Review and chemicals found in water. Neither of these lists should be construed as a list of known or likely endocrine disruptors. For further information on the status of the EDSP, the policies an d procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our website. 5

In this proposed interim decision , EPA is making no human health or environmental safety findings associ ated with the ED SP screening of sodium acifluorfen . Before completing this Registration Review, the Agency will make an EDSP FFDCA section 408(p) determination.



### IV. PROPOSED INTERIM REGISTRATION REVIEW DECISION

A. Risk Mitigation and Regulatory Rationale

As discussed in the Ecological Risk Assessment Section of this document, sodium acifluorfen

may pose a potential risk concern for non

- target terrestrial plants exposed to off

- target spray drift from aerial applications. I n evaluating potential risk mitigation for sodium acifl uorfen, EPA considered the risks, the benefits, and the use pattern of this comp ound. EPA believes that there may be potential risk to non

- target plants from the use of sodium acifluor fen. However, these
risks are outweighed by the benefits associated with use of this compound. To address the se potential risks to non

- target plants, EPA is proposing risk mitigation measures.

Spray Drift Reduction As discussed in the ecological risk assessme nt section of this docume nt, sodium acifluorfen poses a potential risk concern for non

- target terrestrial plants exposed to off

- target spray drift

4 See http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPPT

- 2009

- 0477

- 0074 for the final second list of chemicals.

5 http://w ww.epa.gov/endo/15

from aerial applications . To address spray drift concern s , the sodium acifluorfen registrants have agreed to undertake label language amendments regarding spray drift parameters , including droplet size, uniform across all labels.

T hese label amendments are expected to reduce the extent of environmental exposure and risk to

non

- target plants and animals. Although the Agency is not making a complete listed species safety finding at this time, these label amendments are expected to reduce the extent of exposure

a nd may reduce risk to listed species whose range and/or critical habitat co

- occur with the use of
sodium acifluorfen

. F or sodium acifluorfen , registrants have committed to amending labels where necessary to standardize the following parameters :

 Select nozzles and pressure that deliver medium (VMD 226

- 325) or coarser spray droplets as indicated in nozzle manufacturer’s catalogs and in accordance with ASABE
Standard S

- 572.

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

 For aerial applications, the release height must be no higher than 10 feet from the top of the crop canopy, unless a greater application height is required for pilot safety.

 For aerial applications, the distance of the outer most nozzles on the boom should not
exceed three

- fourths of the length of the wingspan or rotor diameter. To further reduce drift, use one

- half of the length of the wingspan or rotor diameter at the edge of a field

.

 Applicators may not spray during temperature inversions

 For ground applications

, boom height must be no higher than 4 feet above the crop

canopy.

The Agency is encouraging the development of pesticide drift reduction technologies (or DRTs;

see http://www.epa.gov/reducing

- pesticide

- drift/about

- drift

- r eduction

- technology

- program ) that will help realize user, societal, and environmental benefits including:

 reducing the loss of pesticide from the application site,

 improving pest control,

 slowing the advancement of herbicide

- resistant weed populations,

 r educing pesticide exposures to people, wildlife, and the environment, and

 reducing risks of damage and liabilities from off

- target deposition of drift.

Furthermore, EPA believes that the use of proven DRTs will provide users with a wider range of options for addressing drift concerns. Such DRTs could include specialized nozzles, spray shields, and drift

- reducing adjuvant chemicals. The Agency encourages users and producers of
sodium acifluorfen to consider, test, and use these types of innovations as par t of the risk management plan for sodium acifluorfen. DRTs are expected to be useful in mitigating the risks drift poses to non

- target species, and particularly in addressing risks to listed species.

Prohibiting Aerial Applications to Strawberries
Curren t sodium acifluorfen labels permit aerial applications to all registered use sites, including strawberries. Aerial applications provide the greatest potential for exposure to non

- target plants and other taxa because of the increased potential for spray dri ft. To address spray drift concerns, sodium acifluorfen registrants have agreed t o prohibit the aerial application method for strawberries. Usage data available to EPA do not indicate that sodium acifluorfen is applied16

aerially to strawberries

, and EPA bel ieves that removal of this application method will not adversely affect growers.

Herbicide

- Resistance Management The development and spread of herbicide resistant weeds in agriculture is a widespread problem that has the potential to fundamentally change production practices in US agriculture. While
herbicide resistan t weeds have been known since the 1950s, the number of species and their geographical extent, has been increasing rapidly. Currently there are 249 weed species
worldwide with confirmed herb icide resistance, especially since the turn of the century. In the United States there are 155 weed species with confirmed resistance to one or more herbicides.

Management of herbicide resistant weeds, both in mitigating established herbicide resistant weeds and in slowing or preventing the development of new herbicide resistant weeds

, is a complex problem without a simple solution. Coordinated efforts of growers, agricultural extension, academic researcher, scientific societies, pesticide registrants, and state and federal agencies are required to address this problem.

The EPA, Office of Pesticide Programs (OPP) is proposing measures for the pesticide registrants to provide growers and users with detailed information and recommendations to slow the
dev elopment and spread of herbicide resistant weeds. This is part of a more holistic, proactive approach recommended by crop consultants, commodity organizations, professional/scientific societies, researchers, and the registrants themselves. OPP’s approach is measured, based on the inherent risk of weed resistance developing for a given herbicide, considering the target weeds and the agronomic practices of the registered crops. Situations with the least concern for the development of herbicide resistant we eds will have the fewest resistance management elements and the situations with the highest concern will have additional resistance management elements.

Implementation Timeline and Opportunities for Public Comment on Herbicide Resistance Approach

OPP is proposing to implement herbicide resistance measures for existing chemicals during registration review, and to implement herbicide resistance measures for new chemicals and new uses at the time of registration. In registration review, proposed herbicide r esistance elements

will be included in every herbicide proposed interim decision. Comments on these chemical

s pecific measures are welcomed. The Agency will also soon issue a Pesticide Registration Notice (PRN) that will provide additional guidance to reg istrants. All stakeholders are encouraged to

comment

. Public comments received on b oth the sodium acifluorfen PID and the PRN will be considered prior to the final decision on sodium acifluorfen.

S odium acifluorfen acts to inhibit the protoporphyrinogen oxidase (PPO) enzyme, a key enzyme in the production of precursor molecules needed for the photosynthesis. PPO inhibitors also result in the formation of highly reactive molecules that attack and destroy lipids and protein
membranes. This herbicide is cl assified by the Weed Science Society of America (WSSA) as belonging to mechanism of action (MOA) Group 14. This MOA has three confirmed herbicide
resistant weeds.17

This MOA is of moderate concern for weed resistance development because of the existing ca ses of confirmed herbicide resistant weeds. Currently there are no herbicide resistant crops. Proposed herbicide resistance management elements for sodium acifluorfen include:

On the label
1. List Mechanism of Action (MOA) WSSA Group 14.
2. List seasonal and annual maximum number of application s and rates for all crops

. 3. List best management practices for Herbicide Resistance (as appropriate to crop)

. 4. State that user should scout before and after application.
5. List the definition of likely resistance on l abel

. 6. State that user should report lack of performance to registrant or their representative.
7. List confirmed resistant weeds in a separate table and list effective or recommended rates
for these weeds with the table.

Reporting, Education, and Stewardshi p 8. Registrant s should report new cases of likely and confirmed resistance to EPA and users yearly. This will be in addition to any adverse effects reporting.

B. Tolerance Amendments

The Agency will modify the tolerance expression so that it appropriately covers the metabolites and degradates of sodium acifluorfen and that it specifies the residues to be measured for each commodity. In addition, tolerances will be modified to include the recommended number of significant figures.

C. Proposed Interim Registration Review Decision

In accordance with 40 CFR Sections 155.56 and 155.58, the Agency is issuing this P roposed
I nterim R egistration R eview D ecision. Except for the EDSP

, ESA and pollinator components of this case, the Agency has m ade the following Proposed Interim Registration Review Decision: (1) no additional data are required at this time; and (2) changes to the affected registrations and their labeling are needed at this time.

In this proposed interim registration review deci sion, EPA is making no human health or environmental safety findings associated with the EDSP screening of sodium acifluorfen , nor is it making a comple te endangered species finding or a complete assessment of effects to pollinators

. Although the Agency is not making an Endangered Species safety find ing at this time, the proposed mitigation described in this document is expected to reduce overall exposure and may reduce risk to listed species. The Agency’s final registration review decision for
sodium acifluorfen will depend upon the result s of an ESA Section 7 consultation with the
Services

, an EDSP FFDCA section 408(p) determination

, and an assessment of the non

- target exposure to bees

.18



### 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 Proposed Interim Registration Review Decision, and placing it in the sodium acifluorfen registration review docket (EPA

- HQ

- OPP

- 2010

- 0135 ) for public comment for 60 days. A Federal Register Notice will announce the availability of this P roposed I nterim R egistration R eview D ecision for
sodium acifluorfen and initiate a 60

- day comment period. If there are no significant comments or
additional information submitted to the dock et during the comment period that leads the Agency to change its proposed decision, EPA will issue an I nterim R egistration R eview D ecision for
sodium acifluorfen (case 2605 ).

B. Implementation of Mitigation Measures

Once the Interim Registration Review Decision is issued in final form, registrants are to submit
amended labels that include the label changes summarized in Appendix B to the Agency for approval within 60 days following issuance of the Interim Registration Review Decision in final
form

. A summary of t he mitigation measure s are described in Appendices A and B.19

Appendix B: Sodium Acifluorfen Label Table

Sum mary of Proposed Labeling Changes for Sodium A cifluorfen
Description Proposed Labeling Language for Sodium acifluorfen
Products Placement on Label

SPRAY DRIFT Spray Drift Language  Select nozzles and pressure that deliver medium (VMD 226

- 325) or coarser spray droplets as indicated in nozzle manufacturer’s catalogs and in
accordance with ASABE Standard S

- 572.

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

 For aerial applications, the maximum release height
must be no higher than 10 feet from the top of the crop canopy, unless a greater application height is required for pilot safety.

 For aerial applications, the distance of the outer most
nozzles on the boom must not exceed three

- fourths of the length of the wingspan or roto r diameter. To further reduce drift, use one

- half of the length of the wingspan or rotor diameter at the edge of a field.

 Applicators may not spray during temperature
inversions

.

 For ground applications, boom height must be no higher than 4 feet above the crop canopy. Directions for Use

HERBICIDE RESISTANCE MANAGEMENT

- Products Labeled for Agricultural Use

Herbicide Mechanism
of Action “Group 1 4 HERBICIDE” Front Panel, upper right quadrant, surrounded by a black (or suitable color) rectangle

Weed Resistance Management  Listing of herbicide mechanism of action (MOA), and/or WSSA herbicide group number, at the top of the first page of each product label; Directions for Use, prior to directions for specific crops under the heading “WEED 

### Appendix A: Summary of Proposed Actions for Sodium Acifluorfen Registration Review Case#: 2605
PC Code: 114402 Chemical Type: herbicide
Chemical Family: Diphenyl ether
Mechanism of Action: WSSA Group 1 4
Affected Population(s) Source of

Exposure Route of

Exposure Duration of

Exposure Risk(s) of

Concern Proposed Action(s)

 Terrestrial

Plants (dicots)  Aerial

Application  Foliar

absorption  Acute  Acute toxicity  Require spray drift reduction

language
 Require herbicide resistance management language for moderate concern group
 Delete aerial application to strawberry20 Sum mary of Proposed Labeling Changes for Sodium A cifluorfen
Description Proposed Labeling Language for Sodium acifluorfen
Products Placement on Label

 List seasonal and annual maximum number of applications and pounds

.

 Resistance Management language from PR Notice
2001

- 5, and/or Best Management Practices (appropriate to crop) from Weed Science Society of America (WSSA) & Herbicide Resistance Action Committee (HRAC), and/or HRAC proposed guidelines for herbicide labels.

 User should scout befor e and after application.

 Include the definition of likely resistance

.

 User should report lack of performance to registrant or their representative

.

 List confirmed resistant weeds in a separate table
and list effective or recommended rates for these
weeds with the table. RESISTANCE
MANAGEMENT”

DIRECTIONS FOR USE

Delete aerial application for strawberry  For strawberry

, aerial application is prohibited. Directions for Use for Strawberry