2

Hydramethylnon 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 Hydramethylnon’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, 

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

Hydramethylnon. Odenkirchen, Zhong. November 15, 2012.

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

Review. Doherty, Oonnithan, Scollon. November 20, 2012.

3. BEAD Chemical Profile for Registration Review: Hydramethylnon (Pyrimidinone) (PC 

Code 118401). Mallampalli, Haddad, Lee. September 10, 2012.

4. Hydramethylnon: Review of Human Incidents. Recore. July 19, 2012.

5. PRD Label Data Report: Food/Feed & Non-Food/Non-Feed Uses Considered in 

Registration Review Work Planning. July 18, 2012.

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

found in the docket EPA-HQ-OPP-2012-0869 at http://www.regulations.gov.
3

OVERVIEW

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

registration review (docket number EPA-HQ-OPP-2012-0869). Hydramethylnon is a slowacting stomach toxicant insecticide registered for use against ants, cockroaches, crickets, 

earwigs, silverfish, and termites. Hydramethylnon products are primarily used to control ants in 

non-crop lands such as lawns, turf, and non-bearing nursery stock. Hydramethylnon is also 

registered for the control of household ant species and cockroaches in nonfood use areas in and 

around domestic dwellings and commercial establishments. In addition to those uses, 

hydramethylnon is registered for use on grasses, rangelands, and in pineapple orchards. This 

Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Programs 

knows about hydramethylnon, 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 hydramethylnon’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 hydramethylnon and what types of new data 

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

hydramethylnon. 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 hydramethylnon. 

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

document provides hydramethylnon’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

The table below summarizes anticipated data needs for hydramethylnon. The environmental 

data needs are primarily driven by the outdoor broadcast application of loose granules. For 

additional discussion of the anticipated data needs, see the Registration Review: Preliminary 

Problem Formulation for Environmental Fate, Ecological Risk, Endangered Species, and 

Drinking Water Exposure Assessments for Hydramethylnon and Hydramethylnon. Human Health 

Assessment Scoping Document in Support of Registration Review.

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

Guideline 

Number Study Title Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

835.2240 Aquatic photodegradation TGAI 12

835.4300 Aerobic Aquatic Metabolism TGAI 24

835.4400 Anaerobic Aquatic Metabolism TGAI 24

850.1025 Acute toxicity estuarine and marine organisms 

(oyster shell growth) TGAI 12

850.1300 Freshwater invertebrate life cycle1 TGAI 12

850.1350 Saltwater invertebrate life cycle1 TGAI 12

850.1400 Fish early-life stage toxicity test (freshwater and 

estuarine/marine)2 TGAI 12

850.2100 Avian oral toxicity (passerine species) TGAI 12

850.4100 Seedling emergence and seedling growth3 TEP 12

850.4150 Terrestrial plant toxicity, vegetative vigor3 TEP 12

850.4400 Aquatic plant toxicity test using Lemna spp3 TGAI 12

850.4500 Algal toxicity3 TGAI 12

850.4550 Cyanobacteria toxicity3 TGAI 12

850.6100

Environmental Chemistry Methods and Associated 

Independent Laboratory Validation for soil and 

water3

TGAI

870.7800 Immunotoxicity TGAI 12

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

 1 The anticipated DCI will specify that testing with either a freshwater invertebrate or an estuarine/marine 

invertebrate (for a species with a valid acute toxicity test) is to be performed. The resulting acute to chronic ratio 

(ACR) will then be applied to the other invertebrates.

2 The anticipated DCI will specify that testing with either a freshwater fish or an estuarine/marine fish (for a species 

with a valid acute toxicity test) is to be performed. The resulting acute to chronic ratio (ACR) will then be applied 

to the other fish.

3 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 website4

.

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 hydramethylnon.

Table 2 provides a summary of the current regulatory status of hydramethylnon.

Table 2: HYDRAMETHYLNON CHEMICAL FACTS

PC code 118401

Case Number 2585

CAS Number 67485-29-4

Year first registered 1980

Pesticide Type Slow-acting stomach toxicant insecticide

Chemical class Trifluoromethyl aminohydrazone

Reregistration Eligibility 

Decision (RED)

December 1998

Tolerance Reassessment 

Eligibility Decision 

(TRED)

Not applicable

Cumulative group Not applicable

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

40 CFR Citation Tolerances for hydramethylnon are established in § 180.395 for use 

on grass (forage and hay) and pineapple.

Dual-use Conventional pesticidal uses only.

Non-pesticidal uses No non-pesticidal uses of hydramethylnon.

Pesticide Re-evaluation 

Division, Chemical 

Review Manager

Steven Snyderman, snyderman.steven@epa.gov, 703-347-0249

Registration Division, 

Product Manager

Mark Suarez, suarez.mark@epa.gov, 703-305-0120

USE AND USAGE INFORMATION

Please see the BEAD Chemical Profile for Registration Review: Hydramethylnon (Pyrimidinone) 

(PC Code 118401) in the registration review docket for more details.

Table 3: USE AND USAGE INFORMATION

Summary of Use Slow-acting stomach toxicant insecticide registered for use against 

ants, termites, cockroaches, crickets, earwigs, and silverfish.

Use Sites Registered agricultural sites include: fruit and nut crops, pineapple, 

grasses, pastures and rangeland.

Registered non-agricultural sites include: golf courses, livestock 

(sleeping quarters, corrals and holding areas), and poultry facilities 

(including poultry houses), forest lands, nursery stock, ornamental 

turf and trees, mulch, storage areas (feed/food), pet kennels, horse 

trailers, zoos, farm or agricultural structures and equipment, 

households (private or commercial domestic dwellings), 

uncultivated nonagricultural uses, sewers, schools, commercial 

transportation facilities, food and feed processing plants or areas, 

eating establishments, food marketing, storage and distribution 

facilities, and hospitals and related institutions.

Summary of Usage EPA has very limited usage data for hydramethylnon. A review of 

the available proprietary and public databases did not show any 

reported agricultural usage data.

Formulation Type(s) Granular, pellet/tablet, gel formulations, bait stations, impregnated 

materials and ready-to-use solutions.

Application Method(s) Products can be applied via granular pellet, aerial broadcast, or 

individual mound treatments and via impregnated materials, though 

often deployed in bait stations that can be used in residential or 

industrial structures.

Technical Registrant(s) BASF Corporation and Bell Laboratories Inc.

No. of Registrations 37 Section 3 products5

Restricted Use No

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

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

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 the design of bait stations.

• 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

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

and county

• Usage/use information for non-agricultural uses (e.g., food handling/processing 

establishments, in and around commercial and institutional facilities)

• Typical application interval (days)

• State or local use restrictions

• Foreign technical registrants not listed above who supply technical hydramethylnon to 

the US market

RECENT ACTIONS

There are no recent actions for hydramethylnon. 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for hydramethylnon was 

completed for a registration-related new use request in 2003 on pineapples. The most recent 

ecological and environmental fate risk assessment was completed in 2003 for the same purpose. 

Findings and conclusions from these risk assessments are summarized in the Registration 

Review: Preliminary Problem Formulation for Environmental Fate, Ecological Risk, 

Endangered Species, and Drinking Water Exposure Assessments for Hydramethylnon and 

Hydramethylnon. 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

hydramethylnon. EPA does not anticipate the need to update dietary, residential, or occupational

risk assessments in registration review, unless the Agency determines that new data or changes 

to the standard operating procedures/default exposure assumptions could alter the previous risk 

conclusions.

The table 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 Hydramethylnon’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 Regarding degradates of concern: The Agency has 

concluded that the stressor of concern is the parent 

hydramethylnon. Two known major degradates6 will 

not be assessed further because of the low toxicity 

based on the ECOSAR analysis. However, several 

unidentified degradates from photolysis and anaerobic 

degradation studies will be assumed as the parent 

hydramethylnon unless they are properly identified.

Incidents Y For a discussion of hydramethylnon reported 

ecological incidents, see page 16 of the Problem 

Formulation.

Human Health

Dietary

Food N It is unlikely that a new assessment will be needed, 

unless the planned drinking water assessment 

determines significant estimated residues in drinking 

water from surface water sources.

Drinking water Y The Agency plans to conduct an assessment of 

drinking water from surface water sources only, since

hydramethylnon appears to have a low potential for 

groundwater contamination.

Occupational

Handlers (mixers, loaders, 

applicators)

N Absent any new toxicity or exposure data, changes to 

the standard operating procedures, or default exposure 

assumptions, the Agency plans to rely on previous 

assessments where there was no risk estimates of 

concern associated with hydramethylnon handler or 

post-application occupational exposure.

Post-application N

Residential

Handlers N There is very low potential for dermal and inhalation 

exposures to residential handlers due to the properties 

of the gel formulation and bait-station packaging.

Post-application N

Other

Aggregate N Evaluates the combined risk from dietary and 

residential exposures. Based on current estimated risk 

levels a new quantitative aggregate risk assessment is 

not likely to be necessary.

Cumulative N/A Hydramethylnon has not been identified as a member 

of a common mechanism group.

 6 1,5-bis(alpha, alpha, alpha-trifluoro-p-tolyl)-1,4-pentadien-3-one (CL98,724, 28%) and 4H-pyrimido [2-1-c]astriazio-4-one1,6,7,8-tetrahydro-7,7-dimethyl-3-[p-(trifluoromethyl)-styryl] (CL247,176, 25.2% and 30.5%)
9

Tolerances Y The tolerance expression for hydramethylnon will be 

reviewed during registration review to ensure that it 

appropriately covers the metabolites and degradates 

of hydramethylnon and that it specifies the residues to 

be measured for each commodity.

Incidents Y For a discussion of hydramethylnon’s reported human 

incidents, see page 10 of the 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 hydramethylnon’s

registration review.

Table 5: Registration Review for Hydramethylnon – Projected Registration Review 

Timeline

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period 2012 – December

Close Public Comment 2013 – February

Case Development

Final Work Plan 2013 – May

Issue DCI 2014 –Jan – March

Data Submission 2016 – Jan – March

30-day Public Comment Period for Draft Risk Assessments 2017 – July – Sept.

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2018 – Jan – March

Registration Review Decision and Begin Post-Decision Follow-up 2018

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 hydramethylnon.
10

Appendix – Additional Areas Considered in Hydramethylnon’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:

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

impaired under section 303(d) of the Clean Water Act7

. In addition, no Total Maximum Daily 

Loads (TMDL) have been developed for hydramethylnon8

. More information on impaired water 

bodies and TMDLs can be found at the Agency’s website9

. 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 Process10 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 hydramethylnon 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://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

8

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES 9 http://www.epa.gov/owow/tmdl/

10 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 hydramethylnon. The ecological risk assessment planned during registration 

review will allow the Agency to determine whether hydramethylnon’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 hydramethylnon, 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 reregistration decision for hydramethylnon, 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), hydramethylnon

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. 

Hydramethylnon 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

hydramethylnon. 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 website11.

HUMAN STUDIES:

Occupational and Residential

Past hydramethylnon 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), 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.

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