2

Cyhalofop-butyl Preliminary Work Plan – Table of Contents 

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

ANTICIPATED DATA NEEDS .................................................................................................... 5

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

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

USE AND USAGE INFORMATION ............................................................................................ 6

RECENT ACTIONS ....................................................................................................................... 7

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW ................................ 7

TIMELINE .................................................................................................................................... 10

NEXT STEPS ............................................................................................................................... 10

Appendix – Additional Areas Considered in the Cyhalofop-butyl Registration Review ......... 11 

References:

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

based on the following documents: 

1. Preliminary Ecological Risk Assessment for Registration Review of cyhalofop-butyl. K. 

Garber and R. Shamblen. September 10, 2014 

2. Cyhalofop-butyl. Human Health Assessment Scoping Document in Support of Registration 

Review. D. Dotson, M. Collantes, J. D’Agostino. September 5, 2014 

3. Cyhalofop-butyl: Tier I Review of Human Incidents. S. Recore and E. Evans. June 25, 

2014 

4. BEAD Chemical Profile (BCP) for Registration Review: Cyhalofop-butyl

(082583). B. Phillips, R. Prieto, and D. Berwald. May 7, 2014

5. Cyhalofop-butyl (082583) Screening Level Usage Analysis (SLUA). February 5, 2014

6. EFED Table 1 Report- Ingredient Cyhalofop-butyl (082583). March 14, 2014
3

7. HED Master Label Report- Ingredient Cyhalofop-butyl (082583). March 14, 2014

These and other supporting documents for the cyhalofop-butyl registration review case may be 

found in the docket EPA-HQ-OPP-2014-0115 at http://www.regulations.gov. 
4

OVERVIEW 

The docket for cyhalofop-butyl is now open, initiating the first public comment period for this 

registration review (docket number EPA-HQ-OPP-2014-0115). Cyhalofop-butyl is an herbicide 

that is registered for use for grass weed control in rice only. This Preliminary Work Plan (PWP) 

document explains what EPA’s Office of Pesticide Programs knows about cyhalofop-butyl, 

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 cyhalofop-butyl. 

 

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 cyhalofop-butyl and what types of new data 

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

cyhalofop-butyl. 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 Agency is releasing a Preliminary Risk Assessment (PRA) for ecological risk concurrent 

with the PWP. Rather than providing a Problem Formulation for planning the ecological risk 

assessment for cyhalofop-butyl, as is usual for docket openings, the Agency has already 

completed its preliminary ecological risk assessment. The preliminary ecological risk assessment 

is included in the cyhalofop-butyl registration review docket, and the Agency is requesting 

comments on the preliminary risk assessment as well as the PWP during the docket opening 

comment period. The Agency does not anticipate conducting another ecological risk assessment 

during the registration review of cyhalofop-butyl. 

The Preliminary Work Plan begins by listing the anticipated data needs for cyhalofop-butyl. 

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 

human health risk assessments, and a projected registration review timeline for cyhalofop-butyl. 

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

ANTICIPATED DATA NEEDS 

Table 1 below summarizes anticipated data needs for cyhalofop-butyl. For additional discussion of the 

anticipated data needs, see the Cyhalofop-butyl. Human Health Assessment Scoping Document in Support 

of Registration Review. 

Table 1: Anticipated Data Needs for the Cyhalofop-butyl Registration Review 

Guideline 

Number Study Title Test Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

Anticipated Data Needs for the Parent Cyhalofop-butyl

870.3465 90-day Inhalation Rat1 TGAI 24 

TGAI = technical grade active ingredient; TEP = typical 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 

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 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 155.40. 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 

 

1

 Although the guideline is for a 90-day study, a 28-day study is considered adequate to satisfy the anticipated data 

requirement. HED’s HASPOC recommended, based on weight-of-evidence considerations, that a subchronic 

inhalation toxicity study is needed; however, if the registrant can provide particle size distribution data for the 

granular product such that HED can determine what fraction of the product is both respirable and inhalable, the 

Agency could re-consider the need for the inhalation study. 

2

 http://www.epa.gov/oppsrrd1/registration_review/ 
6

comment period, the Agency will develop a Final Work Plan (FWP) and anticipated schedule for 

the registration review of cyhalofop-butyl. 

CHEMICAL FACTS 

Table 2 provides a summary of the chemical facts for cyhalofop-butyl. 

Table 2: Chemical Facts for Cyhalofop-butyl

PC code 082583 

Case Number 7255 

CAS Number 122008-85-9 

Year first registered 2002 

Pesticide Type Herbicide 

Chemical class Aryloxy-phenoxy propionate

Reregistration Eligibility 

Decision (RED) 

Because it was registered after November 1984, cyhalofop-butyl 

was not subject to reregistration. 

Tolerance Reassessment 

Eligibility Decision 

(TRED) 

Because it was registered after November 1984, cyhalofop-butyl 

was not subject to tolerance reassessment. 

Cumulative group Not applicable. Cyhalofop-butyl has not been identified as a 

member of a cumulative group that shares a common mechanism 

of toxicity. 

40 CFR Citation Tolerances for cyhalofop-butyl are established in 40 CFR part 

§180.576. 

Dual-use Cyhalofop-butyl 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 cyhalofop-butyl. 

Pesticide Re-evaluation 

Division, Chemical 

Review Manager 

Jolene Trujillo 

trujillo.jolene@epa.gov

703-347-0103 

Registration Division, 

Product Manager 

Kathryn Montague 

montague.kathryn@epa.gov

703-305-1243 

USE AND USAGE INFORMATION 

Table 3 summarizes the use and usage information for cyhalofop-butyl. Please see the BEAD 

Chemical Profile (BCP) for Registration Review: Cyhalofop-butyl (082583) in the registration 

review docket for more details.

Table 3: Cyhalofop-butyl Use and Usage Information

Summary of Use Cyhalofop-butyl is an herbicide that is registered for use on grass 

weed control in rice. 

Use Sites Cyhalofop-butyl is only registered for use on rice. There are no other 

uses (agricultural or nonagricultural). 
7

Table 3: Cyhalofop-butyl Use and Usage Information

Summary of Usage For years 2003-2012, cyhalofop-butyl annual usage averaged 

103,000 pounds of active ingredient (A.I.) treating an annual 

average of 406,000 thousand acres, for an overall average 

application rate of 0.25 pounds A. I. per acre. 

Formulation Type(s) Cyhalofop-butyl is formulated as an emulsifiable concentrate, 

soluble concentrate, granular, and ready-to-use solution. 

Application Method(s) Cyhalofop-butyl can be broadcast aerially or by foliar application 

with ground equipment. 

Technical Registrant Dow AgroSciences 

No. of Registrations 10 Section 3 products3

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. 

 Information on any additional niche weeds that cyhalofop-butyl is used specifically to 

control. Information on any weed species that display potential for resistance. 

 Confirmation 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. 

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

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

and county. 

 Typical application timing (date of first application and application intervals) – national, 

state, and county. 

 Typical application interval (days). 

 State or local use restrictions. 

 Foreign technical registrants not listed above who supply technical cyhalofop-butyl to the 

US market. 

RECENT ACTIONS 

There are no recent or pending actions for cyhalofop-butyl. 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW 

The most recent human health risk assessment for cyhalofop-butyl was completed in 2012 when 

HED evaluated a label amendment to increase the single application rate for use of the herbicide 

on rice. Findings and conclusions from that risk assessment are summarized in the cyhalofopbutyl Scoping Document. 

 

3

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

(http://oaspub.epa.gov/pestlabl/ppls.home). 
8

During registration review, the Agency anticipates the need to conduct a revised occupational 

handler risk assessment and will consider the potential for new bystander drift and volatilization 

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

are required for registration review, they will be considered in the new assessments, along with 

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

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

Scoping Document. As noted in Table 4, EFED has already developed its preliminary risk 

assessment for cyhalofop-butyl. 
9

Table 4: Anticipated Risk Assessments for the Cyhalofop-butyl Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecological and Environmental Fate 

Comprehensive ecological 

(species to be assessed 

include terrestrial and aquatic 

organisms), including an 

assessment of risks to 

threatened and endangered 

species 

No A preliminary risk assessment was conducted at the 

problem formulation stage because the database was 

sufficient to support an ecological risk assessment. 

Based on currently registered uses and labeled rates, 

the preliminary assessment identifies potential risks 

to some non-target organisms. An endangered 

species assessment has not been conducted at this 

time. 

Incidents No Four (4) ecological incidents have been reported for 

cyhalofop-butyl; see page 29 of the risk assessment. 

Human Health 

Dietary 

Food No Unless needed due to any updates to points of 

departure or exposure estimates from the diet. The 

dietary exposure database is adequate to support the 

existing registrations. Dietary exposure estimates 

previously were not of concern. 

Drinking water No Unless needed due to any updates to points of 

departure or exposure estimates from drinking water. 

No drinking water risks of concern have been 

identified as of this time. 

Occupational 

Handlers (mixers, loaders, 

applicators) 

Yes A handler inhalation assessment will be needed to 

account for inhalation toxicity or particle size 

distribution data. 

Post-application No An inhalation occupational post-application risk 

assessment will not be required. 

Residential 

Handlers No There are no residential handler scenarios for 

cyhalofop-butyl. 

Post-application Yes During registration review, the Agency will consider 

the potential for inhalation exposure to bystanders 

through spray drift and volatilization. 

Other 

Aggregate No Unless needed due to any updates to points of 

departure or exposure estimates from food and 

drinking water.

Cumulative No EPA has not made a common mechanism of toxicity 

finding as to cyhalofop-butyl and any other 

substances, and cyhalofop-butyl does not appear to 

produce a toxic metabolite produced by other 

substances. 
10

Tolerances No There are no Codex Alimentarius Commission 

(Codex) or Canadian maximum residue limits 

(MRLs) for cyhalofop-butyl. As a result, there are 

no harmonization issues at the present time. 

Incidents Will check for 

updates 

For a discussion of reported human incidents for 

cyhalofop-butyl, see page 10 of the Scoping 

Document and the Cyhalofop-butyl: Tier I Review of 

Human Incidents. 

TIMELINE 

EPA has created the following estimated timeline for the completion of the cyhalofop-butyl 

registration review in Table 5 below. 

Table 5: Projected Cyhalofop-butyl Registration Review Timeline

Activities Estimated Date

Opening the Docket 

Open Docket and 60-day Public Comment Period 2014 – September 

Close Public Comment 2014 – November 

Case Development 

Final Work Plan 2015 – February 

Issue DCI 2015 April - June

Data Submission 2017 April - June

60-day Public Comment Period for Draft Human 

Health Risk Assessment[1]

2018 Oct. – Dec. 

Registration Review Decision 

60-day Public Comment Period for Proposed 

Registration Review Decision 

 2019 July - September

Registration Review Decision and Begin Post-Decision 

Follow-up 

2020

Total (years) 6 

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 cyhalofop-butyl. 

 

[1] The regulations governing Registration Review generally require the Agency to provide a public comment period 

of at least 30 calendar days for preliminary 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 preliminary risk 

assessments. 
11

Appendix – Additional Areas Considered in the Cyhalofop-butyl 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: 

Cyhalofop-butyl 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, no Total Maximum Daily 

Loads (TMDL) have been developed for cyhalofop-butyl.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 Process7 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 cyhalofop-butyl 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.htm
12

ENDANGERED SPECIES: 

In November 2013, the EPA, along with the U.S. Fish & Wildlife Service (USFWS), the 

National Marine Fisheries Service (NMFS) (collectively, the Services), and the U.S. Department 

of Agriculture (USDA) released a summary of their joint Interim Approaches for assessing risks 

to listed species from pesticides. The Interim Approaches were developed jointly by the 

agencies in response to the National Academy of Sciences’ (NAS) recommendations and reflect 

a common approach to risk assessment shared by the agencies as a way of addressing scientific 

differences between the EPA and the Services. The NAS report outlines recommendations on 

specific scientific and technical issues related to the development of pesticide risk assessments 

that EPA and the Services must conduct in connection with their obligations under the 

Endangered Species Act (ESA) and FIFRA. 

The joint Interim Approaches were released prior to a stakeholder workshop held on November 

15, 2013. In addition, the EPA presented the joint Interim Approaches at the December 2013 

Pesticide Program Dialogue Committee (PPDC) and State-FIFRA Issues Research and 

Evaluation Group (SFIREG) meetings, and held a stakeholder workshop in April 2014, allowing 

additional opportunities for stakeholders to comment on the Interim Approaches. As part of a 

phased, iterative process for developing the Interim Approaches, the agencies will also consider 

public comments on the Interim Approaches in connection with the development of upcoming 

Registration Review decisions. The details of the joint Interim Approaches are contained in the 

white paper “Interim Approaches for National-Level Pesticide Endangered Species Act 

Assessments Based on the Recommendations of the National Academy of Sciences April 2013 

Report,” dated November 1, 2013. 

Given that the agencies are continuing to develop and work toward implementation of the 

Interim Approaches to assess the potential risks of pesticides to listed species and their 

designated critical habitat, the preliminary risk assessment for cyhalofop-butyl does not contain a 

complete ESA analysis that includes effects determinations for specific listed species or 

designated critical habitat. Although EPA has not yet completed effects determinations for 

specific species or habitats, for the preliminary assessment EPA conducted a screening-level 

assessment for all taxa of non-target wildlife and plants that assumes for the sake of the 

assessment that listed species and designated critical habitats may be present in the vicinity of 

the application of cyhalofop-butyl. This screening level assessment will allow EPA to focus its 

future evaluations on the types of species where the potential for effects exists once the scientific 

methods being developed by the agencies have been fully vetted. This screening-level risk 

assessment for cyhalofop-butyl indicates potential risks of direct effects to listed mammals, 

birds, terrestrial invertebrates, fish, and aquatic invertebrates on the sole registered use site. 

Listed species of aquatic and terrestrial plants may also be affected through indirect effects 

because of the potential for direct effects on listed and non-listed species upon which such 

species may rely. Potential direct effects on listed mammals, birds, terrestrial invertebrates, fish, 

and aquatic invertebrates from the use of cyhalofop-butyl may be associated with modification of 

Primary Constituent Elements (PCEs) of designated critical habitats, where such designations 

have been made. Once the agencies have fully developed and implemented the scientific 

methods necessary to complete risk assessments for endangered and threatened (listed) species 
13

and their designated critical habitats, these methods will be applied to subsequent analyses for 

cyhalofop-butyl as part of completing this registration review. 

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 cyhalofop-butyl, 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), 

cyhalofop-butyl 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. A second list 

of chemicals identified for EDSP screening was published on June 14, 20138

 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. 

Cyhalofop-butyl does not appear on either of the lists. 

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

 

8

 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 9

 http://www.epa.gov/endo/ 
14

HUMAN STUDIES: 

Occupational 

Past cyhalofop-butyl 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 generic 

pesticide exposure databases such as the Pesticide Handlers Exposure Database (PHED) and the 

Agricultural Reentry Task Force (ARTF) 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.