2 

### Chlorsulfuron Preliminary Work Plan

– Table of Contents

Overview 3

Anticipated Data Needs 4

Statutory and Regulatory Authority 4

Chemical Facts 5

Use and Usage Information 6

Recent Actions 7

Anticipated Risk Assessment s for Registration Review 8

Timeline 9

Next Steps 9

Appendix

– Additional Areas Considered in Chlorsulfuron ’s Registration Review 1 0

References:

This Preliminary Work Plan summarize s the Environmental Protection Agency's current position based on the following documents:

1. Registration Review

– Preliminary Problem Formulation for Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments for Chlorsulfuron (PC Code 118601; DP Barcode D403354) . M. Clock

- Rust and K. White. November 15, 2012.

2. Chlorsulfuron: Registration Review Scoping Document for Human Health Assessments

. M. Hawkins, S. Piper, and Y. Yung. December 6, 2012.

3. BEAD Chemical Profile for Registration Revie w : Chlorsulfuron

. C. Doucoure, S. Ratnayake, and S. Smearman. June 25, 2012

4. Chlorsulfuron: Review of Human Incidents. S. Recore. July 31, 2012

5. Chlorsulfuron: Screening Level Usage Analysis . May 5, 2012

6. PRD Label Data Report: Food/Feed & Non

- Food/Non

- Feed Uses Considered in Registration Review Work Planning for Chlorsulfuron (118601) August 3, 2012

7. Chlorsulfuron: EPA and DuPont 12/6/2012 Focus Meeting Minutes . December 10, 2012.

These and other supporting documents for the chlorsulfuron registration review case may be

found in the docket EPA

- HQ

- OPP

- 2012

- 0878 at http://www.regulations.gov

.3 OVERVIEW

The docket for chlorsulfuron is now open , initiating the first public comment period for this registration review (docket number EPA

- HQ

- OPP

- 2012

- 0878 )

. Chlorsulfuron is a sulfonylurea

herbicide that is primarily absorbed through the leaves of plants. Sul fonylurea herbicides disrupt the synthesis of amino acids in plants by inhibiting the enzyme acetolactate synthase (ALS). ALS inhibition in plants adversely affects plant growth and reproduction. Although the sulfonylurea herbicides all act upon the same enzyme system in plants, that system is not present

in animals

. C hlorsulfuron is registered for use on barley, oats, wheat, fallow fields, and

ornamental turf for residential lawns, recreational areas, and golf courses. It is applied as a pre

emergence soil treatment and post

- emergence treatment to control broadleaf weeds and certain grass weed species. This Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Programs knows about chlorsulfuron

, highlighting anticipated data and assessment needs, identifying the types of information that would be especially useful to the Agency in conducting the review , and providing an anticipated timeline for completing chlorsulfuron’s

review

.

The registration review process was designed to in clude a public participation component to solicit input from interested stakeholders. The Agency intends, b y sharing this information in the docket, to inform the public of what it knows about chlorsulfuron and what types of new data or

other information would be helpful for the Agency to receive as it moves toward a decision on chlorsulfuron

. The Agency encourages all interested stakeholders to review the PWP and Appendix and to provide comments and additional information that will help the Agency’s

deci sion

- making process for this chemical. In addition to general areas on which persons may wish to comment, there are some areas identified in the PWP and Appendix about which the Agency specifically seeks comments and information. Interested stakeholders could include

environmental non

- profit or interest groups; pesticide manufacturers; agricultural labor or commodity groups; commercial, institutional, residential, and other users of pesticides; or the public at large.

The Preliminary Work Plan begins by listing the anticipated data needs for chlorsulfuron. Next, it discusses the statutory and regulatory authority for R egistration R eview. Then the document provides chlorsulfuron’s chemical facts, use and usage information, recent actions, the anticipated risk assessments, and a projected registration review timeline. Finally, the Appendix

to this document includes identification and discussion of some areas that are considered generally in R egistration R eview along with some additional chemica l case

- specific information.4 ANTICIPATED DATA NEEDS

Table 1 below summarizes anticipated data needs for chlorsulfuron . For additional discussion of the anticipated data needs, see the Registration Review

– Preliminary Problem Formulation fo r Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments for Chlorsulfuron (PC Code 118601; DP Barcode D403354) and Chlorsulfuron: Registration Review Scoping Document for Human Health Assessments

.

Table 1: Anticipated Data Needs for Chlorsulfuron’s Registration Review

Guideline

Number Study Title Test Material Estimated

Timeframe

(Months from receipt of DCI)

835.4100 Aerobic Soil Metabolism PAIRA; TGAI 24

835.4300 Aerobic Aquatic Metabolism PAIRA; TGAI 24

835.4400 Anaerobic Aquatic Metabolism PAIRA; TGAI 24

835.6200 Aquatic (sediment) Field Dissipation Study TEP 24

850.6100 Environmental Chemistry Methods and Associated

Ind ependent Laboratory Validation for soil, water, and plants 1 TGAI 12

870.7800 Immunotoxicity TGAI 12
TGAI = technical grade active ingredient; TEP = typical end

- use product ; PAIRA = p ure active ingredient radio

labeled

STATUTORY AND REGULATORY AUTHORITY

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program

. All pesticides distributed or sold in the United States (U.S.) generally must be registered by the Environmental Protection Agency (EPA or the Agency), based on scientific data showing that they will not cause unreasonable risks to human health o r the environment when used as directed on product labeling. The registration review program is intended to make sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to

meet the statutor y standard of no unreasonable adverse effects to human health or the

environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review program, the Agency periodically reevaluates pesticides to make sure that as change occurs, products in the marketplace can be used safely. Informatio n on this program is provided on EPA’s website

. 2

The Agency is implementing 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. The regulations governing registration review begin at 40 CFR 155.4 0

. T he Agency will consider benefits information and data as required by FIFRA. The public phase of

1 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850

– Ecological Effects Tests

– including renumbering and/or removal of the Tier designation for some guideline studies. See “Final Test Guidelines; OCSPP 850 Series;

Notice of Availability” 77 FR 38282, June 27, 2012. http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPPT

- 2009

- 0154

- 0028

2 http://www.epa.gov/oppsrrd1/registration_revie w/5 registration review begins when the initial docket is opened for each case. The docket is the Agency’s opportunity to state what it knows about the pesti cide and what additional risk analyses and data or information it believes are needed to make a registration review decision. After reviewing and responding to comments and data received in the docket during this initial comment period, the Agency will de velop a F inal W ork P lan (FWP) and anticipated schedule for the registration review of chlorsulfuron

.

Table 2 provides a summary of the current regulatory status of chlorsulfuron.

Table 2: CHLORSULFRON CHEMICAL FACTS

PC code 118601

Case Number 0631

CAS Number 64902

- 72

- 3

Year First R egistered 1982 Pesticide Type herbicide

Chemical class sulfon ylurea

R eregistration Eligibility Decision (R E D) 2005

Tolerance Reassessment Eligibility Decision (TRED) Not applicable.

Cumulative group Chlorsulfuron is currently not part of a cumulative group. EPA has not made a common mechanism of toxicity finding as to

chlorsulfuron and any other substances. In addition,

chlorsulfuron does not appear to produce a toxic metabolite produced by other substances. For t he purposes of Registration Review, therefore, EPA has not assumed that chlorsulfuron has a common mechanism of toxicity with other substances.

40 CFR Citation Tolerances for residues of chlorsulfuron and its metabolites in or on a variety of food and fee d crops are established in 40 CFR §180. 405.

Non

- pesticidal uses No non

- pesticidal uses of chlorsulfuron.

Pesticide Re

- evaluation Division, Chemical Review Manager Kaitlin Keller, keller.kaitlin@epa.gov , (703) 308

- 8172

Registration Division

, Product Manager Kable Davis, davis.kable@epa.gov, (703) 306

- 04156 USE AND USAGE INFORMATION Table 3 summarizes the use and usage information for halosulfuron. Please see the BEAD Chemical Profile for Registration Revie w : Chlorsulfuron. in the registration review docket for

more details

.

Table 3: USE AND USAGE INFORMATION

Summary of Use Selective sulfonylurea herbicide registered for use as preplant, preemergence, and postemergence treatment s to control grasses and

broadleaf weeds.

Use Sites Chlorsulfuron is labeled for us e on mung beans, barley, field corn, oats, proso millet, safflower, sorghum, soybeans, triticale, wheat cotton, pastures, rangeland, forage and fodder grasses, farm yards, and uncultivated agricultural areas. Non

- agricultural use sites

include ornamental lawn and turf, ditch banks, dry flood plains, swamps/marsh bogs/standing water (vegetation), waterway edges, and nonagricultural uncultivated areas. Summary of Usage From 2006

- 2010, agricultural usage of chlorsulfuron averaged approximately 60,000 pounds annuall y and was applied on average to 5,000,000 acres at an overall average rate of 0.012 lbs active ingredient per acre. Winter wheat accounts for approximately 95% of agricultural usage of chlorsulfuron. Chlorsulfuron is primarily used in Kansas, Oklahoma, an d Texas.

Limited data are available for non

- agricultural uses of

chlorsulfuron . In 2006, small amounts of chlorsulfuron were used by lawn care operators and in nursery and floriculture

. Formulation Type Flowable concentrate, granular, and water dispersi ble granules. Application Methods Products can be applied by broadcast, low volume ground spray, and soil and spot treatment using aircraft, handguns, boom sprayers, backpacks, or hand held sprayers. Technical Registrant s E.I. DuPont de Nemours and Company (DuPont) ; Cheminova, Inc. No. of Registrations 34 Section 3 products 3

Restricted Use No

Guidance for Commente rs: Additi onal areas of use and usage related information requested for this registration r eview , and of particular interest to EPA, are described below.

• Certain chlorsulfuron labels are unclear with respect to use in agricultural and non

agricultural uncultivated areas

. A clear definition of what sites are included or excluded based on these terms is needed. Unclear label terminolog y could lead to use of

chlorsulfuron on areas that are not registered use sites. Information on more specific use sites would allow a more refined risk assessment. Defining certain use sites is important in determining where a product may be used, and wh ich endangered species may be in proximity to locations of p otential uses of chlorsulfuron. The Agency intends to work with registrants to address label uncertainties during registration review.

3 Section 3 product labels can be obtained from the Pesticide Produ ct Label System (PPLS) website

( http://oaspub.epa.gov/pestlabl/ppls.home ).7 • More information on chlorsulfuron use in intermittently fl ooded low lying sites, such as seasonally dry flood plains, bogs, marshes, and swamps would improve the ability to predict potential exposure in aquatic systems.

• Chlorsulfuron is classified as Toxicity Category III for acute dermal toxicity and Toxicity Category IV for acute oral toxicity and eye irritation, which requires the Worker Protection Standard (WPS) Restricted

- Entry Interval (REI) of 12 hours. However, s everal labels only include an REI of 4 hours. The Agency will work with registrants to resolve this issue prior to the risk assessment phase of registration review.

• C onfirmation of the following label information : sites of application ; formulations ; appl ication methods and equipment ; maximum application rates ; frequency of application, application intervals, and maximum number of applications per season ; and geographic limitations on use

.

• U se distribution ( e.g. , acreage and geographical distribution of re levant use sites )

• M edian and 90 th percentile reported use rates (lbs ai/ A ) from usage data

– national, state, and county

.

• A pplication timing (date of first application and application intervals)

– national, state, and county

.

• Usage/use information for non

- agricultural uses

.

• General market share information.

• Typical application interval (days)

.

• S tate or local use restrictions

.

• F oreign technical registrants not listed above who supply technical chlorsulfuron to the

US market

.

RECENT ACTIONS

On Thursday, December 6, 2012, EPA met with representatives from Dupont for a focus meeting to discuss usage information, such as lb a.i./yr sold, general market share information, and information on typical use rates vs. maximum use rates, as well as use sit e clarification for

uncultivated areas. The focus meeting discussion is summarized in Chlorsulfuron: EPA and DuPont 12/6/2012 Focus Meeting Minutes

.

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for chlorsulfuron was completed

in 2002 for a registration related new use request on pasture grasses and to support the chlorsulfuron Reregistration Eligibility Decision (RED)

. T he most recent ecological and

environmental fate risk assessment was completed 2005 in preparation for the chlorsulfuron

RED . Findings and conclusions from these risk assessments are summarized in the Registration

Review

– Preliminary Problem Formulation for Ecological Risk and Environmental Fate, Endangered Species, a nd Drinking Water Assessments for Chlorsulfuron (PC Code 118601 ; DP Barcode D403354) and Chlorsulfuron: Registration Review Scoping Document for Human

Health Assessments

.

During registration review, t he Agency anticipates the need to conduct a comprehensive ecological risk assessment, including an endangered species assessment, for all uses of

chlorsulfuron

. For human health, EPA anticipates the need to conduct revised dietary,

residential

, and occupational risk assessment s during registration review

. If toxicological endpoints or points of departure are revised based on the data that are anticipated to be required8 for registration review

, they will be considered in the new assessment s
, as well as any changes to

the standard operating p rocedur es or default exposure assumptions

.

Table 4 below summarizes the anticipated registration review risk assessments based on the

EFED Problem Formulation and HED Scoping Document

.

The Agency plans to rely on the most recent comprehensive human health assessment in making its registration review decision, as there were no risks of concern at that time and changes in Agency models and policies that have occurred since that assessment are not expected to alter risk conclusions. If the results of the additional toxicity study that is expected to be required changes assessment endpoints or uncertainly/safety factors, the Agency will reconsider the need for updated risk assessments.

Table 4: Anticipated Risk Assessments for Chlorsulfuron’s Registration Review

Type of Risk Assessment Conduct ? Notes

Eco logical and Environmental Fate Comprehensive ecological (species to be assessed include terrestrial and aquatic organisms ), including endangered species Y es

Incidents N o Although a formal review is not planned, the Agency will continue to monitor incident data throughout registration review. For a discussion of chlorsulfuron' s reported ecological incidents,

see page 23 of the Problem Formulation.

Human Health Dietary

Food Y es The dietary and drinking water exposure assessments are adequate based on current standards; however a new exposure analysis may need to be conducted during registration review if there are changes to the chlorsulfuron toxicological points of departure and estimated drinking water

concentrations. Drinking water Y es

Occupational Handlers (mixers, loaders, applicators) Y es Due to recent occupational exposure science policy updates, the occupational exposure assessment may need to be updated to reflect current standard operating procedures and to incorporate any new endpoints or uncertainty factors selected based on the anticipated toxicity data requirement

. Post

- application Y es

Residential

Handlers Yes Due to recent residental exposure science policy updates, the residential exposure assessment may need to be updated to reflect current standard operating procedures and to incorporate any new endpoints or uncertainty factors selected based on the anticipated toxicity data requirement. Post

- application Yes

Other9 Aggregate Y es E valuates the combined risk from dietary and residential exposures.

Cumulative N o EPA has not assumed that chlorsulfuron has a

common mechanism of toxicity with other

substances.

Tolerances Y es EPA anticipates updating the current chlorsulfuron tolerance expression in 40 CFR §180. 405 to reflect current Agency policies.

Incidents No For a discussion of chlorsulfuron’s reported human incidents, see page 11 of the Scoping Document.

Guidance for Commente rs: Additional ecological i nformation r equested for this registration r eview , and of particular interest to EPA, is described below.

• Ec ological incidents (non

- target plant damage and avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency

.

• Water quality m onitoring data (see Appendix for further details)

.

TIMELINE

EPA has created the following estimated timeline for the completi on of chlorsulfuron’s registration review in Table 5 below

.

Projected Registration Review Timeline

Activities Estimated Dat e Opening the Docket Open Docket and 60

- day Public Comment Period 2012

- December

Close Public Comment 2013

- February

Case Development

Final Work Plan 2013

- May

Issue DCI 2014

– Jan

– March

Data Submission 2016

– Jan

– March

30

- day Public Comment Period for Draft Risk

Assessments 2017

– July

– Sept.

Registration Review Decision

60

- day Public Comment Period for Proposed Registration Review Decision 2018

– Jan

– March

Registration Review Decision and Begin Post

- Decision

Follow

- up 2018

Total (years) 6

NEXT STEPS

After the 6 0

- day public comment period closes, the Agency will review and respond to any comments received in a timely manner and then issue a Final Work Plan for the registration

review of chlorsulfuron

.10 

### Appendix

– Additional Areas Considered in Chlorsulfuron’s Registration

Review

PUBLIC COMMENTS AND FEEDBACK :

Guidance for C ommenters: The areas below highlight topics of special interest to the Agency where your comments, data submissions, or reference to sou rces of additional information c ould be of particular use.

Trade Irritants:

Through the registration review process, the Agency intends to solici t information on trade irritants and, to the extent feasible, take steps toward facilitating irritant resolution. The Agency

will work to harmonize tolerances and international maximum residue limits (MRL s ) and may modify tolerance levels to do so, when p ossible

. Growers and other stakeholders are asked to

comment on any trade irritant issues resulting from lack of MRLs or disparities between U.S. tolerances and MRLs in key export markets, providing as much specificity as possible regarding

the nature of the concern.

Water Quality:

Chlorsulfuron is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act

. 4 In addition, n o Total Maximum Daily Load s (TMDL) have been developed for chlors ulfuron

. 5 More information on impaired water bodies

and TMDLs can be found at the Agency’s website

. 6 The Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management Process 7 in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

Environmental Justice:

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all people, regardless of race, color, national origin, or income, in the development, implementation, and enforcement of environmental laws, regulations, and policies. To help address potential environmental justice issues, the Agency seeks information on any groups or segments of the popula tion who, as a result of their location, cultural practices, or other factors, may have atypical, unusually high exposure to chlorsulfuron compared to the general population. Please comment if you are aware of any sub

- populations that may have atypical, u nusually high exposure compared to the general population.

4 ht tp://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

5 http://iaspub.epa. gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_ group_name=PESTICIDES

6 http://www.epa.gov/owow/tmdl/

7 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm11 ENDANGERED SPECIES :

A risk assessment that supports a complete endangered species determination has not been

conducted for chlorsulfuron

. The ecological risk assessment planned during registr ation review will allow the Agency to determine whether chlorsulfuron’s use has “no effect” or “may affect” federally listed threatened or endangered species (listed species) or their designated critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical hab itat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropriate.

ENDOCRINE DISRUPTOR 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, neurotoxici ty, 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, estrus cyclicity, sexual maturati on, 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 different taxonomic groups. As part of its reregistration decision for chlorsulfuron

, EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), chlorsulfuron 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 ingredients) 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 required 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 identify any adverse endocrine

- related effects caused b y 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. Chlorsulfuron is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. Accordingly, as pa rt of registration review, EPA will issue future EDSP orders/data

call

- ins, requiring the submission of EDSP screening assays for chlorsulfuron

. For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals,

futu re lists, the test guidelines and the Tier 1 screening battery, please visit our website 8

.

8 http://www.epa.gov/endo/12 HUMAN STUDIES :

Occupationa l and Residentia l

Past chlorsulfuron risk assessments rely in part on data from studies in which adult human subjects were intentionally exposed to a pesticide to determine their dermal and inhalation exposure. Many such studies, involving exposure to many different pesticides, comprise gen eric pesticide exposure databases such as the Pesticide Ha ndlers Exposure Database (PHED), the Agricultural Reentry Task Force (ARTF) Database , and the Outdoor Residential Exposure Task Force (ORETF) Database

. EPA has reviewed all the studies supporting t hese multi

- pesticide generic exposure databases, and has found no clear and convincing evidence that the conduct of any of them was either fundamentally unethical or significantly deficient relative to the ethical standards prevailing at the time the resea rch was conducted. A ll applicable requirements of EPA’s Rule for the Protection of Human Subjects of Research (40 CFR Part 26) have been

satisfied , and t here is no regulatory barrier to continued reliance on these studies

.