Docket Number: EPA-HQ-OPP-2011-0482 

www.regulations.gov 

Ancymidol Summary Document 

Registration Review: Initial Docket 

 June 2011 

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TABLE OF CONTENTS 

 Page No. 

I. Preliminary Work Plan (PWP) ................................................. 4 

II. Fact Sheet .................................................................................... 10 

III. Summary of Data Gaps ............................................................. 13 

 

________________________________________ 

Please Note 

This Preliminary Work Plan and Fact Sheet summarize the Environmental Protection Agency's 

current position based on the following documents: 

1. Registration Review – Preliminary Problem Formulation for the Environmental Fate, 

Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for 

Ancymidol, dated March 28, 2011. 

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

Review, dated June 7, 2011. 

3. Ancymidol Review of Human Incidents. March 1, 2011. 

4. Chemical Profile for Registration Review: Ancymidol. November 19, 2010. 

5. Ancymidol: California Department of Pesticide Regulation Usage Data. July 20, 2010. 

Additional supporting documents for ancymidol may be found in the ancymidol registration 

review docket located on the internet at: www.regulations.gov
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I. Preliminary Work Plan – Ancymidol 

Introduction: 

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

pesticides sold or distributed in the United States 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 

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. Information on this 

program is provided at: http://www.epa.gov/oppsrrd1/registration_review/. 

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 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 and commit to a final work plan and 

schedule for the registration review of ancymidol. 

Ancymidol is a plant growth regulator registered for treating container-grown herbaceous plants, 

ornamental woody shrubs, and bedding plants grown in greenhouses and other plant bedding 

areas for commercial production. There are no food/feed or residential uses of products 

containing this active ingredient. Growth regulator effects produced by ancymidol are the result 

of inhibition of gibberellin biosynthesis. Since gibberellin promotes growth, treatment with 

ancymidol induces a more compact growth form by suppressing growth between nodes. 

Ancymidol was subject to a Reregistration Eligibility Decision (RED), which was completed in 

June 1995. 

 

Anticipated Risk Assessment and Data Needs: 

The Agency anticipates updating and revising the ecological risk assessment, including an 

endangered species risk assessment, for the outdoor uses of ancymidol. EPA believes that the 

existing qualitative human health assessment for ancymidol is adequate to support its registration 

review. Below is a summary of the issues relevant to the registration review of ancymidol and 

the data the Agency anticipates requiring: 
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Ecological Risk: 

• The most recent ecological risk assessment for ancymidol was completed in 1995 

in support of the RED. 

• EPA intends to conduct an ecological risk assessment for the outdoor uses only of 

ancymidol during registration review. The Agency believes that labeled indoor 

uses of ancymidol (i.e., greenhouse, including seed treatment, and interiorscape) 

would not result in sufficient environmental exposure to necessitate an ecological 

risk assessment. 

• The planned assessment would incorporate the most up-to-date modeling 

methodologies, updated assessment endpoints, and data submitted under the 

anticipated registration review data call-in. 

• The Agency has not conducted an ecological risk assessment that supports a 

complete endangered species determination for ancymidol. The ecological risk 

assessment planned during registration review will allow the Agency to determine 

whether ancymidol’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 habitat, the Agency will consult with the U.S. Fish and Wildlife 

Service (FWS) and/or National Marine Fisheries Service (NMFS) (the Services), 

as appropriate. 

• Data gaps exist in the environmental fate and toxicity databases for ancymidol. In 

the ecological risk assessment completed for the 1995 RED, the Agency concluded 

that, because of the limited treated acreage, minor use sites (e.g., ornamental 

flowers and shrubs), and low toxicity cited in the submitted studies, adverse effects 

to birds, mammals, aquatic organisms and non-target plants were expected to be 

minimal. Accordingly, no additional ecological data were required at that time. 

However, based on current environmental fate and ecological risk assessment 

standards, data are anticipated to be needed for the registration review assessment 

of ancymidol. 

• Current formulations with labeled outdoor uses for spray, drench, and chemigation 

applications do not specify maximum application rates per plant type. Maximum 

annual application rates per pot size, or application rates per growing season where 

appropriate, on a chemical weight basis must be specified for the Agency to 

conduct an ecological risk assessment for all outdoor uses; a maximum number of 

sequential applications per plant type must also be defined. 
6

 

• The Agency anticipates requiring the following environmental fate and 

environmental effects data during registration review to support an ecological 

assessment, including an endangered species assessment, of the outdoor uses of 

ancymidol: 

o Guideline (GLN) No. 835. 2240 – Photodegradation in Water 

o GLN No. 835.2410 – Photodegradation in Soil 

o GLN No. 835.4100 – Aerobic Soil Metabolism 

o GLN No. 835.4200 – Anaerobic Soil Metabolism 

o GLN No. 835.4300 – Aerobic Aquatic Metabolism 

o GLN No. 835.4400 – Anaerobic Aquatic Metabolism 

o GLN No. 835.6100 – Terrestrial Field Dissipation 

o GLN No. 835.6200 – Environmental Chemistry Analytical Methods for 

Residues in Water and Sediment and Independent Laboratory Validation 

o GLN No. 850.2100 – Avian Oral Toxicity (passerine and waterfowl or 

upland game) 

o GLN No. 850.2200 – Avian Dietary Toxicity Test (waterfowl) 

o GLN No. 850.2300 – Avian Reproduction Test (waterfowl and upland 

game species) 

o GLN No. 850.1025 – Oyster Acute Toxicity Test 

o GLN No. 850.1035 – Mysid Acute Toxicity Test 

o GLN No. 850.1045 – Penaeid Acute Toxicity Test 

o GLN No. 850.1055 – Bivalve Acute Toxicity Test 

o GLN No. 850.1075 – Fish Acute Toxicity Test (Freshwater) 

o GLN No. 850.1075 – Fish Acute Toxicity Test (Estuarine/Marine) 

o GLN No. 850.1300 – Daphnid Chronic Toxicity Test 

o GLN No. 850.1400 – Fish Early-Life Stage Toxicity Test (Freshwater) 

o GLN No. 850.4100 – Nontarget Area Phytotoxicity Tier II, Seedling 

Emergence1

o GLN No. 850.4150 – Nontarget Area Phytotoxicity Tier II, Vegetative 

Vigor1

 

o GLN No. 850.5400 – Nontarget Area Phytotoxicity Tier II, Aquatic Plant 

Growth (Algal Plants) 1

• Please refer to Registration Review – Preliminary Problem Formulation for the 

Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water 

Exposure Assessments for Ancymidol dated March 28, 2011, located in the docket, 

for a detailed discussion of these anticipated risk assessment and data needs. 

1

A Tier II study is expected to be required. The DCI expected to be issued will provide that a Tier I plant study may 

be conducted in lieu of a Tier II study with the understanding that any adverse effects observed by the Tier I study 

would necessitate conduct and submission of a Tier II study as well. 
7

Human Health Risk:

• The most recent human health risk assessment was completed in 1995 in support 

of the RED. This assessment evaluated occupational exposures only, as no 

food/feed or residential uses are registered for ancymidol. 

• The Agency has evaluated the status of the human health assessments for 

ancymidol and determined that no additional human health exposure or hazard 

information are required to support the registration review of ancymidol. 

• Please refer to the Ancymidol. Human Health Assessment Scoping Document in 

Support of Registration Review, dated June 7, 2011, located in the docket, for a 

detailed discussion of the anticipated risk assessment and data needs for human 

health. 

Endocrine Disruptor Screening Program: 

As required by FFDCA section 408(p), ancymidol 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 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. Ancymidol is 

not among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data callins, requiring the submission of EDSP screening assays for ancymidol. For further information 

on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the 

test guidelines and the Tier 1 screening battery, please visit our website: 

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

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

registration review. 

Registration Review for Ancymidol – Projected Registration Review Timeline

Activities Estimated Date 

Opening the Docket 

Open Docket and Public Comment Period 2011 – June 

Close Public Comment 2011 – August 

Case Development 

Final Work Plan 2011 – November 

Issue DCI 2012 – July – Sept. 

Data Submission 2014 – July – Sept. 

Open Public Comment Period for Draft Risk Assessments 2016 – Jan. – March 

Close Public Comment Period 2016 – April – June 

Registration Review Decision 

Open Public Comment Period for Proposed Registration Review 

Decision 

 2016 – July – Sept. 

Close Public Comment Period 2016 – Oct. – Dec. 

Registration Review Decision and Begin Post-Decision Follow-up 2017 

Total (years) 6 

Guidance for Commenters: 

The public is invited to comment on EPA’s preliminary work plan and rationale. The Agency 

will carefully consider all comments as well as any additional information or data provided in a 

timely manner prior to issuing a final work plan (FWP) for ancymidol. 

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. Growers and 

other stakeholders are asked to comment on any trade irritant issues resulting from lack of 

Maximum Residue Limits (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: 

Ancymidol is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act2

. In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for ancymidol3

. More information on impaired water bodies and 

 

2 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 3 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PESTICIDES
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TMDLs can be found on the Agency’s website4

. 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 Process5 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 

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

atypical, unusually high exposure to ancymidol, 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. 

Other Information: 

Stakeholders are also specifically asked to provide information and data that will assist the 

Agency in refining the risk assessments, including any species-specific ecological effects 

determinations. The Agency is interested in receiving the following information: 

1. confirmation on the following label information; 

a. sites of application 

b. formulations 

c. application methods and equipment 

d. maximum application rates in units related to mass per unit area of treatment 

zone 

e. frequency of application, application intervals and maximum number of 

applications per season 

f. geographic limitations on use 

2. use or potential use distribution (e.g., acreage and geographical distribution of 

relevant crops); 

3. use history; 

4. median and 90th percentile reported use rates (lbs. a.i./acre) from usage data – 

national, state, and county; 

5. application timing (date of first application and application intervals) by crop – 

national, state and county; 

6. sub-county crop location data; 

7. directly acquired county-level usage data (not derived from state level data); 

a. maximum reported use rate (lbs. a.i./acre) from usage data – county 

 

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

5 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
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b. median and 90th percentile number of applications – county 

c. total pounds per year – county 

d. the year the pesticide was last used in the county/sub-county area 

e. the years in which the pesticide was applied in the county/sub-county area 

8. typical interval (days); 

9. state or local use restrictions and 

10. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian 

and mammalian mortalities) not already reported to the Agency. 

Next Steps: 

After the 60-day comment period closes, the Agency will review and respond to any comments 

received in a timely manner, and then issue its Final Work Plan (FWP) for ancymidol. 

II. FACT SHEET 

 

Background Information:

• Ancymidol PC code: 108601, CAS No.: 12771-68-5. 

• Registration review case number: 3017. 

• Technical registrants: SePRO Corporation; Fine Agrochemicals. 

• The first ancymidol pesticide product was registered for use in the U.S. in 1973. 

• The RED for ancymidol was completed in June 1995. 

• Ancymidol product reregistration is complete, and the mitigation specified in the 1995 

RED is on current labels. 

• There are currently three end-use products and two technical products registered. 

• There are no tolerances for use of ancymidol in or on food crops under 40 CFR § 180. 

• Pesticide Re-evaluation Division Chemical Review Manager: Eric Miederhoff, 

miederhoff.eric@epa.gov.

• Registration Division Contact: Tony Kish, kish.tony@epa.gov. 

Use & Usage Information: (For additional details, please refer to the Appendix A, SLUA, and 

Chemical Profile documents in the ancymidol docket.) 

• Ancymidol, in the pyrimidine chemical class, is a plant growth regulator registered for 

treating container-grown herbaceous plants, ornamental woody shrubs, and bedding 

plants grown in greenhouses and other plant bedding areas for commercial production. 

• Ancymidol is formulated as a soluble concentrate (solid) or as an emusifiable concentrate 

(liquid). It may be applied by drip irrigation, spray, to pots or containerized soil, or by 

drench foliar and seed treatments. The amount of active ingredient required for an 

optimum growth response depends on pot size, stage of growth, method of application, 

season, and varietal response. 
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• The available agricultural usage data for ancymidol in nurseries/greenhouses only 

indicated that less than 20 pounds active ingredient per year were used nationwide for the 

years 1999, 2002, 2004, and 2006. 

Recent and Pending Actions: 

• There are currently no new use applications under evaluation. 

Ecological Risk Assessment Status:

The following are key findings of the most recent ecological risk assessment for ancymidol. 

Please refer to the Registration Review – Preliminary Problem Formulation for the 

Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure 

Assessments for Ancymidol dated March 28, 2011, located in the docket, for a detailed discussion 

of the ecological risk assessment. 

• The most recent ecological risk assessment for ancymidol was completed in 1995 in 

support of the RED. This assessment identified minimal adverse effects to listed and 

nonlisted fish, aquatic invertebrates, aquatic plants, birds, mammals, beneficial insects, 

and terrestrial plants from the nursery use of ancymidol on containerized plants only. 

However, this determination was based on an incomplete data set (i.e., effects data on 

terrestrial plants and chronic effects data for all species were not available) and 

unspecified maximum application rates. 

Human Health Risk Assessment Status: 

The following are key findings of the most recent human health risk assessments for ancymidol. 

Please refer to the Ancymidol. Human Health Assessment Scoping Document in Support of 

Registration Review, dated June 7, 2011, located in the docket, for a detailed discussion of the 

human health risk assessment. 

• The most recent human health risk assessment for ancymidol was completed in 1995 in 

support of the RED. 

Hazard Characterization: 

• Ancymidol has low acute oral and dermal toxicities (Toxicity Category III for oral and IV 

for dermal exposure). Ancymidol is a mild eye and skin irritant (Toxicity Category III 

and IV, respectively). Ancymidol has low acute inhalation toxicity (Toxicity Category 

III). It is not a dermal sensitizer. 

Dietary (Food and Water): 

• Ancymidol is not registered for use on agricultural commodities intended for human 

consumption. Additionally, concentrations in drinking water are expected to be minimal 
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since the primary use of ancymidol occurs indoors. Therefore, a dietary assessment was 

not conducted for the 1995 RED. 

Residential: 

 

• Ancymidol is not registered for use in residential settings. Therefore, a residential 

exposure risk assessment was not conducted for the 1995 RED.

Occupational: 

• Given the low toxicity of ancymidol and low application rates, the Agency conducted a 

qualitative occupational risk assessment and concluded potential risks to workers to be 

insignificant. 

Aggregate: 

• Ancymidol is not registered for use on agricultural commodities intended for human 

consumption or for use in residential settings. Therefore, an aggregate exposure risk 

assessment was not conducted for the 1995 RED.

Cumulative: 

• The Agency has not determined whether ancymidol shares a common mechanism of 

toxicity with other chemical substances. If, in the future, the Agency determines that new 

information on ancymidol indicates a shared mechanism of toxicity with other chemicals, 

the Agency will revisit the need for including ancymidol in a cumulative risk assessment. 

Incidents: 

Ecological:

• The Ecological Incident Information System (EIIS) and the Avian Incident Monitoring 

System (AIMS) were consulted for reports of ecological incidents associated with 

ancymidol. No incidents involving ancymidol were found in these databases. 

Human Health: 

• No ancymidol human incidents were reported in the Office of Pesticide Programs 

Incident Data System (IDS) since 2002. 

Tolerances and International Harmonization: 

• There are no food/feed uses of ancymidol, thus no tolerances or exemptions from 

tolerances are necessary for ancymidol. 
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Data Call-In Status: 

• Generic data call-ins (GDCI-108601-17067 and GDCI-108601-17395) were issued in 

February and September 1993, respectively. All of these data requirements have been 

fulfilled. 

Labels: 

 

• The labels for ancymidol can be obtained from the Pesticide Product Label System 

(PPLS) website at: http://oaspub.epa.gov/pestlabl/ppls.home. 

Ancymidol Registrations as of April 29, 2011 

Registration No. Product Name Company Name 

67690-2 A-Rest Solution SePRO Corporation 

67690-5 A-Rest Technical SePRO Corporation 

67690-41 A-Rest Seed Treatment SePRO Corporation 

62097-22 Abide Fine Agrochemicals, Ltd. 

62097-23 Ancymidol Technical Fine Agrochemicals, Ltd. 

III. Summary of Data Gaps 

The table below summarizes the anticipated data requirements for ancymidol. The 

Agency anticipates requiring the following environmental fate and environmental effects data 

during registration review to support an ecological assessment of the outdoor uses of ancymidol. 

Please refer to Registration Review – Preliminary Problem Formulation for the Environmental 

Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments for 

Ancymidol for a detailed discussion of these anticipated risk assessment and data needs. 

Guideline 

Number Study Title Test 

Material 

Estimated 

Timeframe 

835.2240 Photodegradation in Water TGAI 12 

835.2410 Photodegradation in Soil TGAI 12 

835.4100 Aerobic Soil Metabolism TGAI 24 

835.4200 Anaerobic Soil Metabolism TGAI 24 

835.4300 Aerobic Aquatic Metabolism TGAI 24 

835.4400 Anaerobic Aquatic Metabolism TGAI 24 
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Guideline 

Number Study Title Test 

Material 

Estimated 

Timeframe 

835.6100 Terrestrial Field Dissipation TGAI 24 

835.6200 Environmental Chemistry Analytical Methods 

for Residues in Water and Sediment and 

Independent Laboratory Validation

TGAI 12 

850.2100 Avian Oral Toxicity (passerine and waterfowl 

or upland game) TGAI6 12 

850.2200 Avian Dietary Toxicity Test (waterfowl) TGAI 12 

850.2300 Avian Reproduction Test (waterfowl and 

upland game species) TGAI 24 

850.1025 Acute Toxicity Estuarine/Marine Organisms 

(Oyster) TGAI 12 

850.1035 Mysid Acute Toxicity Test TGAI 12 

850.1045 Penaeid Acute Toxicity Test TGAI 12 

850.1055 Bivalve Acute Toxicity Test TGAI 12 

850.1075 Freshwater Fish Toxicity (Estuarine/Marine) TGAI 12 

850.1075 Freshwater Fish Toxicity (Freshwater) TGAI 12 

850.1300 Daphnid Chronic Toxicity Test TGAI 12 

850.1400 Fish Early-Life Stage Toxicity Test 

(Freshwater) TGAI 12 

850.4100 Nontarget Area Phytotoxicity Tier II, Seedling 

Emergence7 TEP8 12 

850.4150 Nontarget Area Phytotoxicity Tier II, 

Vegetative Vigor7 TEP 12 

850.5400 Nontarget Area Phytotoxicity Tier II, Aquatic 

Plant Growth (Algal Plants) 7 TEP 12 

 

6

 Technical Grade Active Ingredient (TGAI). 

7

 A Tier II study is expected to be required. The DCI expected to be issued will provide that a Tier I plant study 

may be conducted in lieu of a Tier II study with the understanding that any adverse effects observed by the Tier I 

study would necessitate conduct and submission of a Tier II study as well. 

8

 Typical End-use Product (TEP)