Docket Number EPA-HQ-OPP-2012-0896 

www .regulations.gov 

Bromoxynil Final Work Plan 

Registration Review 

Case Number 2070 

September 2013 

Approved by: ~¥:0"·~ p ~~~.~. Richard P. Keigwin, ~ 

Director 

Pesticide Re-evaluation Division 

Date: 
INTRODUCTION 

This is the Environmental Protection Agency's (EPA or the Agency) Final Work Plan (FWP) fl r 

the registration review of bromoxynil. This case includes the active ingredients bromoxynil 

phenol, bromoxynil octanoate, and bromoxynil heptanoate. The octanoate and the heptanoate 

active ingredients are esters of the phenol active ingredient. These three active ingredients 

(collectively, "bromoxynil") are postemergence broadleafweed herbicides that are registered fl r 

use in grass crops and some tolerant broadleaf crops, as well as non-crop sites. Bromoxynil 

products are registered for use in both agricultural and commercial/industrial settings. A third 

ester ofbromoxynil phenol, bromoxynil butyrate (PC 035303), was previously registered with 

the Agency but currently has no active registrations and is therefore not addressed in this 

Registration Review. This work plan addresses public comments received concerning the 

Preliminary Work Plan (PWP), which was posted in the bromoxynil registration review docket 

(EPA-HQ-OPP-20 12-0896). 

The Agency is implementi!lg the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for . 

registration. Changes in science, public policy, and pesticide use practices occur over time. Th 

registration review program is intended to make sure that, as the ability to assess rjsk evolves d 

as policies and practices change, all registered pesticides continue to meet the statutory standar 

The public phase of registration review begins when the initial docket is opened for each case. 

Information on this program is provided on the Agency's website. 1 

The FWP begins with any updates since the PWP was issued. Next is a summary of substantiv 

comments received during the public comment period for the PWP concerning anticipated data 

needs, expected risk assessments, or the estimated timeline identified in the PWP, and a 

summary of the Agency's responses to those comments. This section is followed by registratio 

review planned data needs, risk assessments expected to be conducted, and the projected 

registration review timeline for bromoxynil. Lastly, there is a discussion of next steps. 

UPDATES SINCE THE PWP WAS ISSUED 

The projected timeline has been updated since the PWP to reflect impacts of recent Agency 

actions shortening the timeframe between FWP and Data Call-In (DCI) issuance and adding a 

quarter in between posting of preliminary risk assessments (PRAs) and proposed decisions. 

Since the PWP, an immunotoxicity study has been submitted to the Agency and is currently in 

review. The immunotoxicity data requirement has been added to the list of planned data needs 

for data compensation purposes. 

SUMMARY OF COMMENTS AND AGENCY RESPONSES 

During the 60-day public comment period on the Bromoxynil Preliminary Work Plan, which 

opened on March 27, 2013 and closed on May 28, 2013, the Agency received three public 

1 http://www .epa.gov/oppsrrd 1/registration _review/ 

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comments. The three parties who submitted comments were the FIFRA Endangered Species 

Task Force (FESTF), the Washington State Pest Management Resource Service at Washington 

State University Tri-Cities, and the technical product registrant Bayer CropScience. The 

comments do not address the timeline or the planned ecological and human health risk 

assessments described in the PWP, but they do address the anticipated data requirements. 

General use and usage data are also provided in these comments. In the PWP, EPA also solicit d 

comments on the specific topics of environmental justice, water quality concerns, and trade 

irritants, but no comments or information were received on those issues. 

Summarized public comments and Agency responses related to the anticipated ecological risk . 

assessment or data needs can be found in the July 17, 2013 document EFED Response to Publi 

Comments Submitted in Response to the Bromoxynil Registration Review Problem Formulatio 

PWP in the docket, EPA-HQ-OPP-2012-0896. The Agency thanks all commenters for their 

comments and will consider the information supplied by them as EPA conducts the registratio 

review and makes its registration review decision. 

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PLANNED DATA NEEDS 

Table 1 below summarizes the planned data needs for bromoxynil based on the EFED Respons 

to Public Comments Submitted in Response to the Bromoxynil Registration Review Problem 

Formulation PWP. Since the PWP, an immunotoxicity study has been submitted to the Agenc 

and is currently in review. The immunotoxicity data requirement has been added to the list of 

planned data needs for data compensation purposes. 

Table 1: Planned Data Needs for the Registration Review of Bromoxynil 1 

Estimated 

Guideline Study Title 

Timeframe 

Number Test (Months from Material 2 

receipt of DCI) 

Bromoxynil (phenol) - PC Code 035301 

835.2240 Photodegradation in water 12 

835.4100 Aerobic soil metabolism TGAI or 24 PAIRA 835.4300 Aerobic aquatic metabolism 24 

850.6100 Environmental Chemistry Methods and Associated TGAI 12 lndepen.dent Laboratory Validation 3 

850.2300 A vi an reproduction 4 TGAI 24 

850.4400 Aquatic plant growth (aquatic vascular plant) 12 TGAI 

850.4500 Aquatic plant growth (algal plant) 12 

870.7800 lmmunotoxicity ) TGAI 12 

875.2100 Dislodgeable foliar residue and turf transferable TEP 24 residues 

Bromoxynil octanoate- PC Code 035302 

835.4100 Aerobic soil metabolism TGAl or 

PAIRA 24 

850.6100 Environmental Chemistry Methods and Associated 

Independent Laboratory Validation 3 TGAI 12 

850.2100 A vi an oral toxicity 6 TGAI 12 

875.2 100 Dislodgeable foliar residue; turf transferable TEP 24 Residues 

Bromoxynil heptanoate 7 - PC Code 128920 

835.1230 Adsorption/Desorption (Batch Equilibrium) 12 

835.2120 Hydrolysis 12 

835.2240 Photodegradation in water 12 

835.2410 Soil photolysis TGAI or 12 

835.4100 Aerobic soil metabolism PAIRA 

24 

835.4300 Aerobic aquatic metabolism 24 

835.4400 Anaerobic aquatic metabolism 24 

850.6100 Environmental Chemistry Methods and Associated TGAI 12 Independent Laboratory Validation 3 

875.2100 Dislodgeable foliar residue and turf transferable TEP 24 

residues 

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1 On June 27,2012, EPA announced certain revisions in harmonized guideline series 850 - Ecological Effects Tess 

- including renumbering and other designations or changes for some guideline studies. See "Final Test Guideline ; 

OCSPP 850 Series; Notice of Availability" 77 FR 38282, June 27, 2012. 

http://www.regulations.gov/#! documentDetail ;D=EPA-HO-OPPT -2009-0 154-0028 2 TGAI = technical grade active ingredient; TEP = typical end-use product; PAIRA = pure active ingredient, radio 

labeled 

3 This ECM/ILV anticipated data need is for methods in water. 4 An avian reproduction study with bromoxynil (phenol) is an anticipated data requirement. In absence of these d a 

if they are required, the available endpoints for bromoxynil octanoate will be used for risk assessment. 

5 Bromoxynil (phenol), bromoxynil heptanoate and bromoxynil octanoate have been determined by the Agency to e 

toxicologically equivalent on a molar basis (0374609- Bromoxynil: Human Health Risk Assessment for Amende 

Uses on Grass Grown for Seed, Conservation Reserve Program Areas, and Grain Sorghum, C. Walls, 04/2012011 . 

As such, data from an acceptable immunotoxicity study for one of the three bromoxynil forms data will bridge to e 

other forms and be sufficient for satisfying the immunotoxicity anticipated data need for this registration review 

case. 

6 For this anticipated data requirement, the study expected to be requested would be for a passerine species. The 

anticipated Data Call-In Notice will require that a protocol for the study be submitted to EPA for approval before he 

study begins. 7 The Agency will review where it is appropriate to bridge the results of environmental fate studies conducted wit 

bromoxynil octanoate to bromoxynil heptanoate. If bridging is determined to be an acceptable strategy, aqueous 

photolysis, aerobic aquatic metabolism, anaerobic aquatic metabolism, soil photolysis, and adsorption/desorption 

studies using bromoxyn il heptanoate likely would not be required. 

RISK ASSESSMENTS FOR REGISTRATION REVIEW 

During registration review, the Agency anticipates the need to conduct a comprehensive 

ecological risk assessment, including an endangered species assessment, for all uses of 

bromoxynil. For human health, EPA anticipates the need to conduct an occupational risk 

assessment during registration review. If drinking water estimates do not need revision, a 

revised dietary assessment for bromoxynil may not be required for the purpose of registration 

review. If toxicological endpoints or points of departure are revised based on the data that are 

anticipated to be required for registration review, they will be considered in the new assessmen s, 

as well as any changes to the standard operating procedures or default exposure assumptions. 

Table 2 below summarizes the planned registration review risk assessments based on the EFE 

Problem Formulation and HED Scoping Document. The planned assessments have not change 

from what was included in the PWP. 

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Table 2: Planned Risk Assessments for the Bromoxynil Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecolotdeal and Environmental Fate 

Comprehensive ecological Yes 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Incidents Yes For a discussion ofbromoxynil's reported ecolo r.ical 

incidents, see page 17 of the Problem Forrnulati< n. 

Human Health 

Dietary 

Food No A new dietary risk assessment may not be neede ~ 

because changes in the Agency's assessment me hods 

since the most recently conducted risk assessme tare 

not anticipated to affect the risk conclusion. 

If drinking water estimates do not need revision, a 

revised dietary assessment for bromoxynil may ot be 

required for the purpose of registration review. 

Drinking water Yes 

Occupational 

Handlers (mixers, loaders, Yes 

applicators) 

Post-application Yes 

Residential 

Handlers No There are no residential uses of bromoxynil. 

Post-application No 

Other 

Aggregate Yes Evaluates the combined risk from food and drinl< ing 

water exposures. 

Cumulative No Bromoxynil is not a member of a cumulative grc up 

and no cumulative risk assessment is planned. 

Tolerances Yes Tolerances for bromoxynil are listed in 40 

CFR§ 180.324. 

Incidents No There is not a concern at this time that would wa rrant 

further investigation. The Agency will continue 0 

monitor the incident information and, if a concer s 

triggered, additional analysis will be included in he 

risk assessment. For a discussion ofbromoxynil s 

reported human incidents, see page 1 0 of the Sc< ping 

Document. 

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TIME LINE 

EPA has created the following estimated timeline for the completion of the bromoxynil 

registration review in Table 3 below. The projected timeline has been updated since the PWP p 

reflect impacts of recent Agency actions shortening the time frame between FWP and DCI 

issuance and adding a quarter in between posting of PRAs and proposed decisions. 

Table 3: Registration Review for Bromoxynil - Projected Registration Review Timelin4 

Activities Estimated Date 

Opening the Docket 

Open Docket and 60-day Public Comment Period March 20 13 - Complet! d 

Close Public Comment May 2013 -Completed 

Case Development 

Final Work Plan August 2013 - Complet d 

Issue DCI 2014: Jan. - March 

Data Submission 20 16: Jan. -March 

60-day Public Comment Period for Draft Risk Assessments' 20 17: July - Sept. 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review 2018: Jan. -March 

Decision 

Registration Review Decision and Begin Post-Decision Follow-up 2019 

Total (years) 6 

NEXT STEPS 

As noted previously, the Agency plans to require several environmental fate, ecological effects 

and human health studies for bromoxynil through a Data Call-In Notice, expected to be issued ~ 

January- March of2014. 

7 The regulations governing Registration Review generally require the Agency to provide a public comment perio 

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, tt e 

Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments. 

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