Docket Number EPA-HQ-OPP-20 14-0200 www.regulations.gov



## Imazapyr Preliminary Work Plan

Registration Review: Initial Docket
Case Number 3078 ·

Approved by:

Date: 

## May2014**~~P~,:O** Richard P. Keigwin, Jr.
Director
Pesticide Re-evaluation Division2 

### Imazapyr Preliminary Work Plan

– Table of Contents

OVERVIEW

................................ ................................ ................................ ................................ ... 4

ANTICIPATED DATA NEEDS

................................ ................................ ................................ .... 4

STATU TORY AND REGULATORY AUTHORITY

................................ ................................ ... 4

CHEMICAL FACTS

................................ ................................ ................................ ...................... 5

USE AND USAGE INFORMATION

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

RECENT ACTIONS

................................ ................................ ................................ ....................... 8

ANTICIPATED R ISK ASSESSMENTS FOR REGISTRATION REVIEW

................................ 8

TIMELINE

................................ ................................ ................................ ................................ .... 10

NEXT STEPS

................................ ................................ ................................ ............................... 10

Appendix

– Additional Areas Considered in the Imazapyr Registration Review

.................... 11

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 the Ecological Risk Assessment and Drinking Water Exposure Assessment to be Conducted for Imazapyr and Imazapyr Isopropylamine PC Code 128829 (isopropylamine salt) and 128821 (imazapyr

a cid) . James Hetrick and Tanja Crk. March 10, 2014.

2. Imazapyr, Isopropylamine Salt: Registration Review Scoping Document for Human Health
Assessment . Mohsen Sahafeyan, Nancy McCarroll, and Bridgett Bobowiec. March 4, 2014.

3. Imazapyr: Tier I Review of Human Incidents . Shanna Recore. January 23, 2014.

4. BEAD Chemical Profile for Registration Review: Imazapyr (128821) and Imazapyr, Isopropylamine salt (128829)

. Sunil Ratnayake, Cynthia Doucoure, and Derek Berwald. March 14, 2014.3

5. Imazapyr (128821): Screening L evel Usage Analysis . April 29, 2013

.

6. EFED Table 1 Report: Imazapyr (128821). March 12, 2014



### .

7. HED Master Label Report: Imazapyr (128821)

. March 12, 2014.

These and other supporting documents for the imazapyr registration review case may be found in
the docket EPA

- HQ

- OPP

- 2014

- 0200 at http://www.regulations.gov

.4

OVERVIEW

The docket for i mazapyr (imazapyr and the isopropylamine salt of imazapyr) is now open

, initiating the first public comment period for this registration review (docket number EPA

- HQ

OPP

- 2014

- 0200 )

. This case includes the following active ingredients: imazapyr (PC code 128821) and the isopropylamine salt (PC code 128829) of imazapyr

, the two collectively hereafter referred to as imazapyr

. Imazapyr is a non

- selective systemic herbicide registered for use as pre and post

- emergent treatments for control of a broad spectrum of terrestrial and aquatic
weeds. This Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Progra ms knows about imazapyr

, 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 the registration review for imazapyr

.

The registration review process was designed to include 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 imazapyr and what types of new data or other information would be helpful for the Agency to receive as it moves toward a decision on imazapyr

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

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 speci fically 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 pestici des; or the public at large.

The Preliminary Work Plan begins by listing the anticipated data needs for imazapyr

. Next, it discusses the statutory and regulatory authority for R egistration R eview

. Then the document provides chemical facts, use and usage i nformation, recent actions, the anticipated risk assessments, and a projected registration review timeline for imazapyr

. Finally, the Appendix to this document includes identification and discussion of some areas that are considered generally
in R egistrati on R eview along with some additional chemical case

- specific information.

ANTICIPATED DATA NEEDS

There are no anticipated data needs for the imazapyr registration review. For additional
discussion of why there are no anticipated data needs, see the Regist ration Review

– Preliminary Problem Formulation for the Ecological Risk Assessment and Drinking Water Exposure Assessment to be Conducted for Imazapyr and Imazapyr Isopropylamine (PC Code 128829 (isopropylamine salt) and 128821 (imazapyr acid) and Imazapyr , Isopropylamine Salt: Registration Review Scoping Document for Human Health Assessment

.

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 that5

they will not cause unreasonable risks to human health or the envi ronment 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 statutory 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

. 1

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 155.40

. T he Agency
will consi der benefits information and data as required by FIFRA

. The public phase of 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 pesticide and what additional ri sk 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 develop a F inal W ork P lan (FWP ) and anticipated schedule for the registration review of imazapyr

.

CHEMICAL FACTS

Table 1 provides a summary of the chemical facts for imazapyr

.

Table 1 : Chemical Facts for Imazapyr

PC code 128821 (imazapyr), 128829 ( isopropylamine salt )
Case Number 3078
CAS Number 81334

- 34

- 1 (imazapyr), 81510

- 83

- 0 ( isopropylamine salt )

Year first registered 1985 (technical); however, non

- crop end use registered July 1984 Pesticide Type Herbicide
Chemical class I midazolinone

R eregistration Eligibility
Decision (R E D) September 2006

Tolerance Reassessment Eligibility Decision (TRED) Not applicable ; the tolerance s were reassessed when new food uses were established, 68 FR 55475

- 55485

Cumulative group Not applicable , imazapyr has not been identified as a member of a cumulative group that shares a common mechanism of toxicity
40 CFR Citation Tolerances for imazapyr are established in 40 CFR § 180.500
Dual

- use Imazapyr is registered for conventional pesticidal uses only and has no registered antimicrobial or biopesticidal uses.

Non

- pesticidal uses There are no identified non

- pesticidal uses of imazapyr

1 http://www.epa.gov/oppsrrd1/registration_review/6 Table 1 : Chemical Facts for Imazapyr

Pesticide Re

- evaluation Division, Chemical Review Manager Joel Wolf, wolf.joel@epa.gov

, 70 3

- 347

- 0228

Registration Di vision

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

- 306

- 0415

USE AND USAGE INFORMATION

Table 2 summarizes the use and usage information for imazapyr

. Please see the BEAD Chemical Profile for Registration Review: Imazapyr (128821) and Imazapyr, Isopropylamine salt (128829) in the registration review docket for more details

.

Table 2 : Imazapyr Use and Usage Information

Summary of Use Imazapyr is a non

- selective systemic herbicide registered f or use
as pre

- and post

- emergent treatments to control broad spectrum of terrestrial and aquatic weeds including terrestrial annual and perennial grasses ; broadleaf weeds ; herbs ; woody species ; and riparian and emergent aquatic weed species. In additio n, i mazapyr is registered for use i n controlling grasses and broadleaf weeds in Clearfield® production systems where the crop is tolerant to
imidazolinone herbicides.
Use Sites Agricultural Use Sites: Imazapyr is registered for use on field corn

. I mazapyr and the isopropylamine salt of imazapyr are registered for use on conifer plantations, forestry sites, and grass pastures and rangelands, as well as agricultural non

- crop areas. Non

- Agricultural Use Sites:

I mazapyr is registered for use on wildlife openings, non

agricultural non

- crop areas, animal housing premises (outdoor), outdoor residential areas (paved ar e as, driveways, patios, etc.), recreational areas, commercial/institutional/industrial areas, and in aquatic s ites (ponds, lakes, stre ams, etc.)

. Imazapyr is also registered for use on established turf grass on industrial grounds, athletic fields, cemeteries, parks, golf course roughs, and institutional grounds. In addition, imazapyr is registered for d irect application to potable surfac e water, public waters, private waters, livestock watering ponds, and recreational water areas

. Summary of Usage Agricultural u s age of imazapyr : T he average annual pounds of a.i. applied has decreased by 86% from 19,600 lbs a.i during the period 2003

- 2007 to 2,700 lbs a.i. during the more recent period of 2008

- 2012

. Non

- agricultural usage of imazapyr : I n 2011 ~42 00 lbs a.i. was reportedly used on institutional turf
and lawn care , 50% more than the amount of a.i. used for7 Table 2 : Imazapyr Use and Usage Information

agriculture ; widely reported use as an aquatic herbicide in Florida

, quantity used un known ; Bureau of Land Management usage ranged from ~1200

- 8000 lbs a.i. from 2003

- 2011. Formulation Type(s) Imazapyr is commonly formulated as soluble and emulsifiable concentrates, wettable powder, and water dispersible granules. The isopropylamine salt of imazapyr is commonly formulated as aqueous and ready

- to

- use solutions. Application Method(s) Imazapyr is applied as a ground application using handheld equipment (backpack sprayers, sprinkling cans, handgun sprayers, high

- pressure handwand sprayers) or granular broadcast applications using push

- type or backpack spreaders

. It can also be applied as an aerial spray. Technical Registrant (s) BASF Corporation , E.I. DuPont de Nemours and Co, Agan Chem MFG. Ltd, Nufarm Limited, Tide International, USA, Inc., Forerock, LLC No. of Registrations Imazapyr

- 32 Section 3 products 2 Imazapyr, Isopropylamine Salt

– 46 Section 3 products, 10
Section 24 (c) products
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.

 Information about use in uncultivated non

- agricultural areas, outdoor residential areas (paved areas, driveways, patios, etc.), and aquatic sites (ponds, lakes, streams, etc.), including pounds a.i. applied, application timing, application rate, application method, and application frequency

.

 C onfirmation of the following label information : sites of application ; formulations ; application 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 relevant use sites )

.

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

– national, state,
and cou nty

.

 Typical a pplication timing (date of first application and application intervals)

– national, state, and county

.

 Usage/use information for non

- agricultural uses

.

 Typical application interval (days)

.

 S tate or local use restrictions

.

 F oreign technical re gistrants not listed above who supply technical imazapyr to the US
market

.

2 Section 3 product labels can be obtained from the Pesticide Produ ct Label System (PPLS) website ( http://oaspub.epa.gov/pestlabl/ppls.home ).8

RECENT ACTIONS

An ecological assessment for a special local need FIFRA Section 24(c) was conducted in May
2010 . The FIFRA Section 24(c) action was to allow broadcast application of imazapyr (Arsenal PowerLine EPA Reg. No. 241

- 431) on grass pasture for control of cogongrass (Imperata cylindrica) in areas that may be grazed or cut for hay.

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for imazapyr was completed in 2013 to support import tolerances without U. S. registration for residues of imazapyr on
imidazolinone

- tolerant soybean of Cultivance® weed control s ystem, rapeseed subgroup 20A,
sunf lower subgroup 20B and lentil. T he most recent ecological and environmental fate risk assessment was completed in August 2010 to add aquatic use sites to the Arsenal PowerlineTM herbicide (EPA Reg. No. 241

- 431) label to allow direct application of imazapyr to potable surface water, public waters, private waters, livestock watering ponds, and recreational water
areas at a maximum rate of 1.5 lb a cid equivalents /A per year. Findings and conclusions from
these risk assessments are summarized in the Registratio n Review

– Preliminary Problem Formulation for the Ecological Risk Assessment and Drinking Water Exposure Assessment to be Conducted for Imazapyr and Imazapyr Isopropylamine (PC Code 128829 (isopropylamine salt) and 128821 (imazapyr acid) and Imazapyr, Iso propylamine Salt: Registration Review Scoping Document for Human Health Assessment

.

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 imazapyr

. For human health, EPA will not require a risk assessment for registration review because after reviewing the toxicology database for imazapyr, EPA has concluded, with reason able certainty that dietary, occupational

, and residential exposures to imazapyr do not pose a significant human
health risk and

, therefore, risk assessment s are not needed. This is because although there is potential for exposure to imazapyr and although the existing toxicology studies do not use doses up to the limit dose, the available data are high quality and no hazard was identified from the toxicity studies. Prior to completing the imazapyr registration review case, pursuant to FFDCA section 408(p), EPA will make a determination regarding imazapyr under the Endocrine Disruptor Screening Program (EDSP)

.

T able 3 below summarizes the anticipated registration review risk assessments based on the
EFED Problem Formulation and HED Scoping Document

.9

Table 3 : Anticipated Risk Assessments for the I mazapyr 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 A quantitative risk assessment will be conducted

Incidents Will check for updates For a discussion of currently reported ecological

incidents for imazapyr , see page 14 of the Problem
Formulation.

Human Health Dietary
Food N Because imazapyr does not pose a dietary (food and drinking water) risk, a quantitative dietary risk assessment is not required. Drinking water N

Occupational Handlers (mixers, loaders, applicators) N Because imazapyr does not pose an occupational risk, an updated or revised occupational risk assessment is

not required. Post

- application N
Residential

Handlers N Because imazapyr does not pose a residential risk, an updated or revised residential risk assessment is not required

. Post

- application N

Other Aggregate N E valuates the combined risk from dietary and residential exposures.
Cumulative N I mazapyr has not been identified as a member of a cumulative group that shares a common mechanism of toxicity
Tolerances N
Incidents Will check for updates For a discussion of currently reported human

incidents for imazapyr , see page 5 of the Scoping

Document and the Imazapyr: Tier I Review of Human
Incidents

.10

TIMELINE

EPA has created the following estimated timeline for the completion of the imazapyr registration
review in Table 4 below

.

Table 4 : Projected Imazapyr Registration Review Timeline

Activities Estimated Dat e Opening the Docket Open Docket and 60

- day Public Comment Period 2014

- June
Close Public Comment 2014

- August Case Development
Final Work Plan 2014

- December

Issue DCI N/A
Data Submission N/A

6 0

- day Public Comment Period for Draft Risk
Assessments 3 201 6 April

- June

Registration Review Decision

60

- day Public Comment Period for Proposed Registration Review Decision 201 7 Jan.

- March

Registration Review Decision and Begin Post

- Decision
Follow

- up 2017

Total (years) 3

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 imazapyr.

3 The regu lations governing Registration Review generally require the Agency to provide a public comment period of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c) . For conventional pesticides, t he Agency plans to provide a 60 calendar day public comment period generally for draft risk assessment s

.11



### Appendix

– Additional Areas Considered in the Imazapyr 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 solicit 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 possible

. Growers and other stakeholders are asked to

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

Water Quality:

Imazapyr 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 imazapyr

. 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 rac e, 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 th e population who, as a result of their location, cultural practices, or other factors, may have atypical, unusually high exposure to imazapyr compared to the general population

. Please comment if you are aware of any sub

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

4 http://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.htm12

ENDANGERED SPECIES :

A risk assessment that supports a complete endangered species determination has not been
conducted for imaz apyr

. The ecological risk assessment planned during registration review will allow the Agency to determine whether use of imazapyr has “no effect” or “may affect” federally listed threatened or endangered species (listed species) or their designated critical hab itats

. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropr iate.

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, includi ng 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,

or gan weights, estrus 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 reproductiv e effects in different taxonomic groups

. As part of its most recent registration decision for imazapyr

, 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), imazapyr 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 ingredient s) 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
de terminations. 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 av ailable data. Tier 2 testing is designed to identify 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 EDS P screening was published on June 14, 2013 8 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.

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

- HQ

- OPPT

- 2009

- 0477

- 0074 for the final second list of
chemicals.13

For further information on the status of the EDSP, the policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our
website. 9

HUMAN STUDIES :

Occupationa l and Residentia l

Past imazapyr risk assessments re ly 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 generic pesticide

exposu re 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 these 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 research was conducted

. A l l 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

.

9 http://www.epa.gov/endo/