Docket Number EPA-HQ-OPP-2013-0749

www.regulations.gov

Aminopyralid Preliminary Work Plan

Registration Review: Initial Docket

Case Number 7267

March 2014

Approved by:

Director

Pesticide Re-evaluation Division

Date:
2

Aminopyralid Preliminary Work Plan -Table of Contents

OVERVIEW ....................................................................................................................................4

AN'flCIPATED DATA NEEDS.....................................................................................................5

STATUTORY AND REGULATORY AUTHORITY ...................................................................5

CHEMICAL FACTS .......................................................................................................................6

USE AND USAGE INFORMATION .............................................................................................? 

RECENT ACTIONS .......................................................................................................................9

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW.................................9

TIMELINE ....................................................................................................................................11

NEXT STEPS ................................................................................................................................12

Appendix -Additional Areas Considered in the Aminopyralid Registration Review ..............13

References:

This Preliminary Work Plan summarizes the Environmental Protection Agency's current position 

based on the following documents:

1. Registration Review: Problem Formulation for Environmental Fate, Ecological Risk, 

Endangered Species, and Human Health Drinking Water Exposure Assessments for 

Aminopyralid, Potassium Salt of Aminopyralid, and Triisopropanolamine Salt of 

Aminopyralid. EFED!Edward Scollon, Ph.D. and Katrina White, Ph.D. February 12, 2014.

2. Aminopyralid. Human Health Assessment Scoping Document in Support of Registration 

Review. HED/Douglas Dotson, Ph.D., Jaime D'Agostino, Ph.D. and Zaida Figueroa, 

February 12, 2014.

3. Aminopyralid: Tier l Review of Human Incidents. Shanna Recore. November 12, 2013.

4. BEAD Chemical Profile (BCP )for Registration Review: Aminopyralid Case Level

Composed of Aminopyralid (005100), Aminopyralid, Potassium Salt (005219) and
3

Triisopropcmolamine Salt of Aminopyralid (005209). BEAD/Sunil Ratnayake, Rafael A. 

Prieto and Stephen Smearman, March 31,2014.

5. Aminopyralid (005100, 005209,005219). Screening Level Usage Analysis (SLUA),

March 18, 2014.

6. Environmental Fate and Effects Division Label Data Report Spreadsheet: PC Codes:

005100, 005209,005219. August 23, 2013.

7. Health Effects Division Master Label Report Spreadsheet: PC Codes: 005100,

005209,005219. August 23, 2013.

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

found in the docket EPA-HQ-OPP-2013-0749 at http://www.re!!ulalions.gov.
4

OVERVIEW

The docket for aminopyralid is now open, initiating the first public comment period for this 

registration review (docket number EPA-HQ-OPP-2013-0749). This case includes the 

aminopyralid acid along with its potassium and triisopropanolamine salts. Aminopyralid, 4-

amino-3,6-dichloro-2-pyridinecarboxylic acid, is a systemic herbicide which is registered for use 

to control a number of noxious and invasive annual, biennial and perennial weed species. This 

pesticide belongs to the pyridine carboxylic acid family and is registered for use as a preemergence and post-emergence herbicide to control broadleaf weed species in many agricultural 

and non-agricultural use sites. Aminopyralid acts like a plant growth regulator by mimicking 

natural plant growth hormones (auxins) and disrupting the plant's normal growth process,

causing abnormal growth patterns in the plants. Aminopyralid may be applied via aircraft, 

ground sprayer, hand-held sprayer, and boom sprayer. Aminopyralid may also be applied to 

forest plantings via broadcast, high volume spray, spot treatment, stump treatment, girdle 

treatment, frill treatment, tree wound treatment, and tree injection. This Preliminary Work Plan 

(PWP) document explains what EPA's Office of Pesticide Progra ms knows about aminopyrlid, 

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 aminopyralid.

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The Agency intends, by sharing this information in the 

docket, to inform the public of what it knows about aminopyralid and what types of new data or 

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

aminopyralid. 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 

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 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 aminopyralid. Next, 

it discusses the statutory and regulatory authority for Registration Review. Then the document 

provides chemical facts, use and usage information, recent actions, the anticipated risk 

assessments, and a projected registration review timeline for aminopyralid. Finally, the 

Appendix to this document includes identification and discussion of some areas that are 

considered generally in Registration Review along with some additional chemical case-specific 

information.
5

Table 1: Anticipated Data Needs for the Aminopyralid Registration Review

Guideline

Number Study Title

1

Test Material

Estimated

Timeframe

(Monthsfrom 

receipt of DCI)

Anticipated Data Needsfor the Aminopyralid

835.4300 Aerobic aquatic metabolism TGAI 24

835.7100 Prospective Groundwater monitoring study TEP 1 2

850.1010 Freshwater invertebrate acute toxicit/ TEP 12

850.4100 Seedl ing emergence (soybean, lettuce, onion)

2 TEP 24

850.4150 Vegetative vigor (soybean, lettuce, onion/·

3

TEP 24

850.4500 Aquatic plant growth (fresh diatom, Naviculla

pelliculosa) 3 TEP 1 2

850.4550 Cyanobacteria Toxicity TGAI 12

850.6100 Environmental Chemistry Methods and

Independent Laboratory Val idation for compost

TGAI 12

Nonguideline Compost Dissipation Study TEP 12

Nonguideline

Honey bee larval toxicity test (OECD 237) TGAI 1 2

ANTICIPATED DATA NEEDS

Table 1 below summarizes anticipated data needs for aminopyralid. For additional discussion of 

the anticipated data: needs, see the Registration Review Problem Formulation for Environmental 

Fate, Ecological Risk, Endangered Species, and Human Health Drinking Water Exposure 

Assessments for Aminopyralid, Potassium Salt of Aminopyralid, and Triisopropanolamine Salt of 

Aminopyralid and the Human Health Assessment Scoping Donrment in Support of Registration 

Review.

TGAI == techmcal grade acttve mgredtent; TEP =typ1cal end-use product

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 or the environment when used as directed

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

-incl uding renumbering and other designations or changes for some guideline studies. See "Final Test Guidelines; 

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

2

For these Guideline Numbers, data and/or waiver requests are currently under review.

3 Data are anticipated to be needed for representative Typical End-Use Products (TEPs) that contain i) aminopyralid 

and 2,4-D; ii) aminopyralid and triclopyr; iii) aminopyralid and clopyralid ; iv) aminopyralid and metsulfuron; and v) 

aminopyralid and fluroxypyr-l-methylheptyl ester
6

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 

e.nvironment. 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. Information on this 

program is provided on EPA's website.

4

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 CPR 155.40. The 

Agency will consider 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 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 develop a Final Work Plan (FWP) and anticipated schedule for 

the registration review of aminopyralid.

CHEMICAL FACTS

Table 2 provides a summary of the chemical facts for aminopyralid.

Table 2: Chemical Facts for Aminopyralid

PC codes 005100 (aminopyralid acid), 005219 (aminopyralid potassium 

salt), 005209 (aminopyralid triisopropanolamine [TIPA] salt)

Case Number 7267

CAS Numbers 150114-71-9 (aminopyralid acid), 566192-87 (aminopyralid

potassium salt), 566191-89-7 (aminopyralid TIPA salt)

Year first registered 2005

Pesticide Type Herbicide

Chemical class Pyridine carboxylic acid

Reregistration Eligibility

Decision (RED)

Aminopyralid was registered after November 1984; therefore, it

was not subject to reregistration.

Tolerance Reassessment

Eligibility Decision (TRED)

Aminopyralid was registered after November 1984; therefore, it

was not subject to tolerance reassessment.

Cumulative group No cumulative risk assessment is required at this time since the

Agency has not made a determination regarding a common mode 

of action.

40 CFR Citation Tolerances for aminopyralid are established in 40 CPR§180.610.

Dual-use Aminopyralid is registered for conventional pesticidal uses only

and has no registered antimicrobial or bio

Non-pesticidal uses There are no identified non-pesticidal uses of aminopyralid.

4

http://www.epa.gov/oppsrrd 1/registration_review/
7

Table 2: Chemical Facts for Aminopyralid

Pesticide Re-evaluation 

Division, Chemical Review 

Manager

Veronica Dutch, dutch.veronica@epa.gov, (703) 308-8585

Registration Division,

Product Manager Kathryn Montague, montague.kathryn@ega.gov, (703) 305-1243

USE AND USAGE INFORMATION

Table 3 summarizes the use and usage information for aminopyralid. Please see the BEAD 

Chemical Profile (BCP) for Registration Review: Aminopyralid Case Level Composed of 

Aminopyralid (005100), Aminopyralid, Potassium Salt (005219) and Triisopropanolamine Salt 

of Aminopyralid (005209) in the registration review docket for more details.

Table 3: Aminopyralid Use and Usage Information

Summary of Use Aminopyralid. is a systemic herbicide registered for broadleaf weed

management in agricultural and non-agricultural lands. 

Arninopyralid can be applied as pre-emergence or post-emergence 

treatments using aerial and ground application methods. 

Aminopyralid acts like a plant growth regulator by mimicking 

natural plant growth hormones (auxins).

Use Sites Use sites for amlnopyralid are wheat, hay, and pasture crops.

Use sites for aminopyralid potassium salt are forestry plantings, 

wheat, hay, and pasture crops. It is also registered for use on 

Conservation Reserve Program (CRP) lands, rights-of-way, and 

fallow and non-agricultural uncultivated areas, including seasonally 

flooded wetland areas when dry.

Use sites for aminopyralid TIPA salt include forest plantings, 

wheat, corn (silage, field), and hay and pasture crops. It is also 

registered for use on CRP areas, airports/landing fields, industrial 

and construction areas, fallow and non-agricultural uncultivated 

agricultural uncultivated areas, including seasonally flooded 

wetland areas when dry.

The predominant use for these active ingredients is on pasture

(98+% of usage).

Summary of Usage Based on proprietary data from 2006-2012, average usage was 

approximately 92,000 pounds of active ingredient (a.i.) applied

annually on 1.3 million acres. The average a.i. rate over this time 

period was 0.07 pounds a.i./acre. There are limited usage data 

available for non-agricultural use sites.

Formulation Type(s) Ami

Ami

nopyralid is formulated as an emulsifiable concentrate. 

nopyralid potassium salt is formulated as a dry flowable and
8

Table 3: Aminopyralid Use and Usage Information

emulsifiable concentrate. Aminopyralid triisopropanolainine salt is 

formulated as an emulsifiable concentrate, liquid soluble 

concentrate, and flowable concentrate.

Application Method(s) Products can be applied as a broadcast treatment by aircraft, ground

sprayer, or hand-held sprayer. Additional treatments are spot 

treatment, stump treatment, girdle treatment, frill treatment, tree 

wound treatment, and tree injection.

Technical Registrant Dow Agro $ciences LLC

No. of Registrations 15 Section 3 products:> and 36 Special Local Needs (SLN; Section

24c) registrations.

Restricted Use No

Guidance for Commenters: Additional areas of use and usage related information

requested for this registration review, and of particular interest to EPA, are described below.

• Certain current labels with instructions for applications to trees (e.g., cut surface, cut-stump 

treatment, tree injection, hack and squirt treatment, and frill and girdle method) do not 

specify the maximum amount of aminopyralid that may be applied per tree ( e.g., as a 

function of trunk diameter), or the maximum number of trees that may be treated per acre. 

Maximum application rates (both single and seasonal) in lbs a.i or a.e./A for modeling 

exposures resulting from these types of uses may also be lacking as is the maximum number 

of applications per year and minimum retreatment interval.

• Some labels list nonspecific use sites. Without specific use site information, the Agency 

must employ the assumption that aminopyralid can be used at any of the specific use sites 

that fall within the broad range of agricultural, commercial, residential, and forest sites 

named on the label, and that applications may be made to both aquatic and terrestrial 

environments. The following are examples of nonspecific use sites:

o Non-irrigation ditch banks, seasonally dry wetlands (such as flood plains, deltas,

marshes, swamps, or bogs), transitional areas between upland and lowland sites when 

dry, ditch bank weeds, shoreline weeds, non-cropland areas, and natural areas.

• Some label restrictions are specified on a product basis. rather than on an a.i. basis.

• Some labelsJack maximum annual or seasonal application rates, maximum number of 

applications, and minimum retreatment intervals.

• Some labels with multiple a.i.s provide application rate information on an acid equivalent 

basis but do not specify to which a.i. the rates apply.

• Confirmation of additional label information: application methods and equipment, and 

geographic limitations on use.

• Use distribution (e.g., acreage and geographical distribution of relevant use sites).

5

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

(http://oa\pub.epa.gln,foestlabllppls.home).
9

o Median and 90th percentile reported use rates (lbs ai/A) from usage data -national, state, and 

county.

f) Typical application timing (date of first application and application intervals)-national, 

state, and county.

o Usage/use information for non-agricultural sites.

o State or local use restrictions.

o Foreign technical registrantthat supply technical aminopyralid to the US market.

RECENT ACTIONS

In 2013, an amendment to registration for a Section 3 new use of aminopyralid for control of 

broadleaf and woody plants and annual weeds in aquatic sites was submitted. The proposed labels

defined aquatic sites as "non-irrigation ditch banks; seasonally dry wetlands such as flood

plains, deltas, marshes, swamps, or bogs; transitional areas between upland and lowland sites 

as well as along shorelines; and shallow areas of still and moving water." The submission is 

currently under review. .

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

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

in 2009. The most recent ecological and environmental fate risk assessment was completed in

2010. Findings and conclusions from these risk ass·essments are summarized in Aminopyralid. 

Human Health Assessment Scoping Document in Support of Registration Review and

Registration Review Problem Formulation for Environmental Fate, Ecological Risk, Endangered 

Species, and Human Health Drinking Water Exposure Assessments for Aminopyralid, Potassium 

Salt of Aminopyralid, and Triisopropanolamine Salt of Aminopyralid.

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

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

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

aggregate risk assessments during 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, as will any changes to the standard operating procedures or default 

exposure assumptions.
10

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

EFED Problem Formulation and HED Scoping Document.

Table 4: Anticipated Risk Assessments for the Aminopyralid Registration Review

Type of Risk Assessment Conduct? Notes

Ecolofdcal and Environmental Fate

Comprehensive ecological

(species to be assessed

include terrestrial and aquatic 

organisms), including 

endangered species

y

The Agency will conduct a comprehensive ecological 

assessment, including an endangered species 

assessment. Effects of residues in compost will be 

addressed.

Incidents Will check for 

updates

For discussion of reported ecological incidents for

aminopyralid, see page 17 of the Problem

Formulation.

Human Health

Dietary

Food

y

If new policies are put into place, or new toxicity and

crop treated data become available, the Agency will 

revisit.

Drinking water y

Drinking water will be examined as part of 

registration review.

Occupational

Handlers (mixers, loaders, 

applicators) y

The Agency will consider the need for a new handler

assessment to account for any policy changes that 

take place during registration review.

Post-application

N

An occupational quantitative post-application

assessment will not be necessary during registration 

review because a dermal endpoint has not been

selected for aminopyralid.

Residential

Handlers

N

Aminopyralid is not applied by homeowners;

therefore, a residential handler assessment will not be 

conducted for registration review.

Post-application

y

During registration review, a revised residential

exposure assessment that includes post-application 

incidental oral exposure to children (1 <2 years old) 

playing on treated recreational sites may be needed. 

The Agency may determine that a bystander spray 

drift risk assessment is needed for aminopyralid 

during registration review.

Other

Aggregate

y

If food, drinking water, or residential port-application

reassessments are conducted, a new aggregate risk 

assessment may be needed.
11

Cumulative

N

Aminopyralid has not been identified as belonging to

a cumulative group, so the Agency does not anticipate 

that a cumulative risk assessment will be performed.

Tolerances yThe Agency will revisit the tolerances during

registration review.

Incidents

Will check for 

updates

For a discussion of reported human incidents for

aminopyralid, see page 10 of the Seeping Document 

and Aminopyralid: Tier I Review of Human 

Incidents.

Guidance for Commenters: Additional ecological information requested for this 

registration review, and of particular interest to EPA, is described below.

o Ecological incidents (non-target plant damage and avian, fish, rep_tilian, amphibian 

and mammalian mortalities) not already reported to the Agency.

o The application of aminopyralid to vegetative matter that issubsequently used as 

compost or animal feed has been found to retain aminopyralid residues and affect

non-target plants. Residues in food items that end up in compost may also be found in

compost. The Agency is interested in additional information about this issue, 

which may include incident reports and environmental fate data.

o Water quality monitoring data (see Appendix for further details).

TIMELINE

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

registration review in Table 5 below.

Table 5: Projected Aminopyralid Registration Review Timeline

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period March-2014

Close Public Comment May-2014

Case Development

Final Work Plan August-2014

Issue DCI October-December-2014

Data Submission October-December-2016

60-day Public Comment Period for Draft Risk Assessments

0 April-June-2018

Registration Review Decision

60-day Public Comment Period for Proposed Registration

Review Decision

January-March-2019

Registration Review Decision and Begin Post-Decision

Follow-up

2020

Total (years) 6

6

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, the 

Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments.
12

NEXT STEPS

After the 60-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 aminopyralid.
13

Appendix -Additional Areas Considered in the Aminopyralid Registration Review

. PUBLIC COMMENTS AND FEEDBACK:

Guidance for Commenters: The areas below highlight topics of special interest to the Agency 

where your comments, data submissions, or reference to sources of additional information could 

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 (MRLs) 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. 

tolerances and MRLs in key export markets, providing as much specificity as possible regarding 

the nature of the concern.

Water Quality:

Aminopyralid is not identified as a cause of impairment for any watebodies listed as impaired 

under section 303(d) of the Clean Water Act.

7 In addition, no Total Maximum Daily Loads 

(TMDLs) have been developed for aminopyralid.

8 More information on impaired water bodies 

and TMDLs can be found at the Agency's website.

9 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 Proces/ 0in 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, V!e Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to aminopyralid 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.

7

http://ias.pub.epa.gov/tmdl watersI 0/attamnation cyxause detail 303d'?p cause group id-!Hl5

8

http://iaspub.cpa.gov/tmdl \'>atersI0/attains nation.tmdl pollutant detail?p pollutant l!fOUQ id-885&p pollutant

group name=PESTICIDES

9

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

10

http://www.epa.gov/oppsnd !/registration re\ ie\\/water quality '>Op.htm
ENDANGER ED SPECIES:

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

conducted for aminopyralid. The ecological risk assessment plaiUled during registration review 

will allow the Agency to determine whether use of aminopyralid 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 habitat, 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, 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, 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 reproductive effects in different 

taxonomic groups. As part of its most recent registration decision for aminopyralid, 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), 

aminopyralid is subject to the endocrine screening part of the Endocrine Disrupter 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 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

1 1 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 disrupters.

11 See http://w\vw.regulation-,.gov/#!documcntDetaii:D-EPA-HO-OPPT-2009-0477-0074 for the final second list of 

chemicals.

. 14
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. 12

HUMAN STUDIES:

Past aminopyralid risk assessments rel y 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 exposure databases such as the Pesticide Handlers 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. All applicable requirements of 

EPA's Rule for the Protection of Human Subjects of Research (40 CFR Part 26) have been 

satisfied, and there is no regulatory barrier to continued reliance on these studies.

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

15