2

Dimethomorph Preliminary Work Plan – Table of Contents 

Overview 3 

Anticipated Data Needs 4 

Statutory and Regulatory Authority 5 

Chemical Facts 5 

Use and Usage Information 6 

Recent Actions 7 

Anticipated Risk Assessments for Registration Review 7 

Timeline 9 

Next Steps 9 

Appendix – Additional Areas Considered in Dimethomorph’s Registration Review 10 

References:

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

based on the following documents: 

1. Registration Review: Preliminary Problem Formulation for Environmental Fate and 

Ecological Risk, Endangered Species, and Drinking Water Assessments for Dimethomorph.

S. Carey. January, 31, 2013. 

2. Dimethomorph: Human Health Assessment Scoping Document in Support of Registration 

Review. S. Piper. January 31, 2013. 

3. BEAD Chemical Profile for Registration Review: Dimethomorph. C. Chen. July 27, 2012. 

4. Dimethomorph: Review of Human Incidents. S. Recore. November 8, 2012.

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

found in the docket EPA-HQ-OPP-2013-0045 at http://www.regulations.gov. 
3

OVERVIEW

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

registration review (docket number EPA-HQ-OPP-2013-0045). Dimethomorph is a systemic 

morpholine fungicide developed to control downy mildews, late blights, and crown and root rots 

on grapes, potatoes, tomatoes, and other vegetables. Dimethomorph is also registered for use on 

various non-agricultural sites, such as forest trees and ornamental plants, but there are no 

registered residential uses. This Preliminary Work Plan (PWP) document explains what EPA's 

Office of Pesticide Programs knows about dimethomorph, 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 

dimethomorph’s review. 

 

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 dimethomorph and what types of new data or 

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

dimethomorph. 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 dimethomorph. Next, 

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

provides dimethomorph’s chemical facts, use and usage information, recent actions, the 

anticipated risk assessments, and a projected registration review timeline. Finally, the Appendix 

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

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

 
4

ANTICIPATED DATA NEEDS

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

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

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

for Dimethomorph and Dimethomorph: Human Health Assessment Scoping Document in 

Support of Registration Review. 

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

Guideline 

Number1 Study Title1 

Test Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

835.6100 Terrestrial field dissipation study (full study) TEP 24 

850.1400 Fish early-life stage toxicity (freshwater fish, 

rainbow trout) TGAI 12 

850.2100 Avian oral toxicity (passerine species) TGAI 12 

850.6100 Environmental chemistry methods and associated 

independent laboratory validation for water TGAI 12 

TGAI = technical grade active ingredient; TEP = typical end-use product 

 

 

1

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

– including 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. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0028
5

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 website2

. 

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 

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

the registration review of dimethomoprh. 

CHEMICAL FACTS

Table 2 provides a summary of dimethomorph’s chemical facts. 

Table 2: Dimethomorph Chemical Facts

PC code 268800 

Case Number 7021 

CAS Number 110488-70-5 

Year first registered 1998 

Pesticide Type Fungicide 

Chemical class Morpholine 

Reregistration Eligibility 

Decision (RED) 

Because it was registered after November 1984, dimethomorph was 

not subject to reregistration 

Tolerance Reassessment 

Eligibility Decision 

(TRED) 

Not applicable 

Cumulative group Dimethomorph is not part of a cumulative group. 

 

2

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

Table 2: Dimethomorph Chemical Facts

40 CFR Citation Tolerances for dimethomorph are established in 40 CFR Part 

180.493. 

Dual-use Conventional pesticidal uses only. 

Non-pesticidal uses None 

Pesticide Re-evaluation 

Division, Chemical 

Review Manager 

Monica Wait, E-mail: Wait.monica@epa.gov, Phone: (703) 347-

8019 

Registration Division, 

Product Manager 20 

Driss Benmhend, E-mail: Benmhend.driss@epa.gov, Phone: (703) 

308-9525 

USE AND USAGE INFORMATION

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

Chemical Profile for Registration Review: Dimethomorph in the registration review docket for 

more details. 

Table 3: Dimethomorph Use and Usage Information 

Summary of Use Dimethomorph is a systemic morpholine fungicide which is mainly 

used to control two important crop diseases, downy mildew and late 

blight 

Use Sites Agricultural use sites include lettuce, onions, tobacco, potatoes, 

cucurbits, spinach, cabbage, peppers, grapes, and tomatoes. Nonagricultural use sites include forest trees, herbaceous plants, 

ornamentals, woody shrubs and vines, and ferns. There are no 

registered residential uses. 

Summary of Usage Annual agricultural usage is approximately 35,000 pounds of active 

ingredient (a.i.) with lettuce accounting for approximately 60% of 

usage. In 2006 non-agricultural usage in nurseries was reported to 

be 9,800 pounds a.i. 

Formulation Type(s) Dispersible granules, wettable powder, and emulsifiable and soluble 

concentrates. 

Application Method(s) Products can be applied by groundboom, aerially, or chemigation 

Technical Registrant(s) BASF Corporation 

No. of Registrations 11 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. 

 Confirmation of the following label information: sites of application; formulations; 

application methods and equipment; maximum application rates; frequency of 

 

3

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

(http://oaspub.epa.gov/pestlabl/ppls.home). 
7

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. 

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

and county. 

 Usage/use information for non-agricultural uses. 

 Typical application interval (days). 

 State or local use restrictions. 

 Foreign technical registrants not listed above who supply technical dimethomorph to the 

US market. 

RECENT ACTIONS

Dimethomorph risk assessments were completed in 2011 to support requests for new uses on 

grapes, brassica subgroups 5A and 5B, and green onions. The new uses were granted, tolerances 

were established, and other tolerances were revised in a May 4, 2012 Federal Register Notice (77 

FR 26462). 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

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

on September 15, 2011 for registration related new use requests, as described in “Recent 

Actions” above. The most recent ecological and environmental fate risk assessment was also 

completed in 2011 for the same purpose. Findings and conclusions from these risk assessments 

are summarized in the Registration Review: Preliminary Problem Formulation for 

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

for Dimethomorph and Dimethomorph: Human Health Assessment Scoping Document in 

Support of Registration Review. 

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

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

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

occupational risk assessments. 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 in 

the new assessments, as well as any changes to the standard operating procedures or default 

exposure assumptions. 

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

EFED Problem Formulation and HED Scoping Document. 
8

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

Type of Risk Assessment Conduct? Notes 

Ecological and Environmental Fate 

Comprehensive ecological 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Y For terrestrial exposures, risk calculations will be for 

the parent dimethomorph alone. Due to an 

unidentified degradate at up to 16% of the applied 

radioactivity, for aquatic exposures, risk calculations 

are anticipated to be based on two approaches: 1) 

parent alone and 2) parent dimethomorph plus the 

unidentified degradate, assuming the degradate is 

stable and as toxic as the parent. 

Incidents Will check for 

updates 

Currently, there are no reported ecological incidents 

for dimethomorph. For further information, see page 

12 of the EFED Problem Formulation. 

Human Health 

Dietary 

Food Y Only a chronic dietary exposure assessment is 

anticipated because no acute endpoint has been 

identified for dimethomorph. 

Drinking water Y The previous drinking water assessment used a 

conservative Tier I approach and was conducted for 

the parent dimethomorph only. During registration 

review, the Agency will consider whether an 

unidentified degradate, recovered at up to 16% of 

applied radioactivity, should be included in the 

anticipated drinking water assessment. 

Occupational 

Handlers (mixers, loaders, 

applicators) 

Y The anticipated occupational assessment will be for 

inhalation exposures only because no dermal endpoint 

Post-application Y was identified in available studies. 

Residential 

Handlers N There are no registered residential uses. 

Post-application N 

Other 

Aggregate N Because there are no residential exposures, an 

aggregate assessment, which evaluates the combined 

risk from dietary and residential exposures, is not 

needed. 

Cumulative N Dimethomorph is not part of a cumulative group. 

Tolerances Y Current tolerances, established in 40 CFR Part 

180.493, will be evaluated during registration review. 
9

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

Type of Risk Assessment Conduct? Notes 

Incidents Will check for 

updates 

At this time, there does not appear to be a concern 

that would warrant further investigation of 

dimethomorph human incidents. For a more detailed 

discussion, see Dimethomorph: Review of Human 

Incidents in the docket or page 6 of the HED Scoping 

Document. 

Guidance for Commenters: Additional ecological information requested for this 

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

 Ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency. 

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

TIMELINE

EPA has created the following estimated timeline for the completion of dimethomorph’s 

registration review in Table 5 below. 

Table 5: Projected Registration Review Timeline

Activities Estimated Date

Opening the Docket 

Open Docket and 60-day Public Comment Period 2013 – March 

Close Public Comment 2013 – May 

Case Development 

Final Work Plan 2013 – August 

Issue DCI 2014 – April - June 

Data Submission 2016 – April - June 

60-day Public Comment Period for Draft Risk Assessments 2017 – Oct. - Dec. 

Registration Review Decision 

60-day Public Comment Period for Proposed Registration Review 

Decision 

2018 – April - June 

Registration Review Decision and Begin Post-Decision Follow-up 2019 

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 dimethomorph. 

 
10

Appendix – Additional Areas Considered in Dimethomorph’s 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: 

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

under section 303(d) of the Clean Water Act4

. In addition, no Total Maximum Daily Loads 

(TMDL) have been developed for dimethomorph5. More information on impaired water bodies 

and TMDLs can be found at the Agency’s website6. 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 dimethomorph 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
11

ENDANGERED SPECIES:

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

conducted for dimethomorph. The ecological risk assessment planned during registration review 

will allow the Agency to determine whether dimethomorph’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 

and/or National Marine Fisheries Service (the Services), as appropriate. 

On January 19, 2011, the Center for Biological Diversity and the Pesticide Action Network 

North America filed a lawsuit in the United States District Court for the Northern District of 

California, against the Environmental Protection Agency (EPA) for allegedly failing to undergo 

consultation with the United States Fish and Wildlife Service and the National Marine Fisheries 

Service regarding the effects of over 350 pesticides, including dimethomorph, on over 200 

endangered and threatened species throughout the United States (Center for Biological Diversity, 

et al. v. EPA, et al., No. C 11-00293 (N.D.Cal.). 

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 dimethomorph, 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), 

dimethomorph 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 
12

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. Dimethomorph 

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 

call-ins, requiring the submission of EDSP screening assays for dimethomorph. 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 website8

. 

HUMAN STUDIES:

Occupational 

Past dimethomorph 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. 

 

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