Docket Number EPA-HQ-OPP-2010-0003
www.regulations.gov

Irgarol
Proposed Interim Registration Review Decision
Case Number 5031
September 2020
A MIT A Digitally signed by
/~\|\|| I /~\	ANITA PFASF
PEASE
ANITA PEASE
Date: 2020.09.30
Approved by; c/aol_ -i -i 48:54 -0400'
Anita Pease
Director
Antimicrobials Division
9/30/20
Date: 	

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Table of Contents
I.	INTRODUCTION	4
A. Summary of Irgarol Registration Review	5
II.	USE AND USAGE	6
III.	SCIENTIFIC ASSESSMENTS	7
A.	Human Health Risks	7
1.	Risk Summary and Characterization	7
2.	Human Incidents and Epidemiology	8
3.	Tolerances	8
4.	Human Health Data Needs	8
B.	Ecological Risks	9
1.	Risk Summary and Characterization	9
2.	Ecological Incidents	9
3.	Ecological and Environmental Fate Data Needs	9
C.	International Maritime Organization (IMO) Environmental Actions for Irgarol	10
1. IMO Timeline	10
D.	Alternative Anti foul ant Active Ingredients	10
Table 1: Comparison of Anti foul ant Paint and Coatings	 12
IV.	PROPOSED INTERIM REGISTRATION REVIEW DECISION	 14
A.	Proposed Risk Mitigation and Regulatory Rationale	 14
1.	Proposed Removal of Anti foul ant Paint Uses for Irgarol	 14
2.	Proposed Occupational and Residential Handler Mitigation for the Airless Sprayer
Application of Algaecidal Preserved Paint for Irgarol	 14
3.	Proposed Occupation Handler Mitigation for the Open Pouring of Irgarol Powder
Formulations	15
B.	Tolerance Actions	15
C.	Proposed Interim Registration Review Decision	15
D.	Data Requirements	15
V.	NEXT STEPS AND TIMELINE	15
A.	Proposed Interim Registration Review Decision	15
B.	Implementation of Mitigation Measures	 16
Appendix A: Summary of Proposed Actions for Irgarol	 17
Appendix B: Propose Labeling Changes for Irgarol Products	19
Appendix C: Endangered Species Assessment	20
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Appendix D: Endocrine Disruptor Screening Program
Irgarol Registration Review Team
Human Health and Environmental Fate and Effects
Timothy Dole
Jorge Muniz-Ortiz
Kathryn Korthauer
Siroos Mostaghimi
James Breithaupt
Judy Facey
Timothy Leighton
Melissa Panger
Risk Management
SanYvette Williams
Eric Miederhoff
Rick Fehir
Office of General Counsel
Chris Kaczmarek

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I. INTRODUCTION
This document is the Environmental Protection Agency's (the EPA or the agency) Proposed
Interim Registration Review Decision (PID) for Irgarol (Cybutryne) (PC Code 128996, case
5031), and is being issued pursuant to 40 CFR §§ 155.56 and 155.58. A registration review
decision is the agency's determination whether a pesticide continues to meet, or does not meet,
the standard for registration in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).
The agency may issue, when it determines it to be appropriate, an interim registration review
decision before completing a registration review. Among other things, the interim registration
review decision may require new risk mitigation measures, impose interim risk mitigation
measures, identify data or information required to complete the review, and include schedules for
submitting the required data, conducting the new risk assessment and completing the registration
review. Additional information on irgarol, can be found in the EPA's public docket (EPA-HQ-
OPP-2010-0003) at www.regulations.gov.
FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandates the
continuous review of existing pesticides. All pesticides distributed or sold in the United States
must be registered by the EPA based on scientific data showing that they will not cause
unreasonable risks to human health or to the environment when used as directed on product
labeling. The registration review program is intended to make sure that, as the ability to assess
and reduce risk evolves and as policies and practices change, all registered pesticides continue to
meet the statutory standard of no unreasonable adverse effects. Changes in science, public
policy, and pesticide use practices will occur over time. Through the registration review
program, the agency periodically re-evaluates pesticides to make sure that as these changes
occur, products in the marketplace can continue to be used safely. Information on this program is
provided at https://www.epa.gov/pesticide-reevaluation. In 2006, the agency implemented the
registration review program pursuant to FIFRA § 3(g) and will review each registered pesticide
every 15 years to determine whether it continues to meet the FIFRA standard for registration.
The EPA is issuing a PID for irgarol so that it can (1) move forward with aspects of the
registration review that are complete and (2) implement interim risk mitigation (see Appendices
A and B). The agency is currently working with the U.S. Fish and Wildlife Service and the
National Marine Fisheries Service (collectively referred to as, "the Services") to develop
methodologies for conducting national threatened and endangered (listed) species assessments
for pesticides in accordance with the Endangered Species Act (ESA) Section 7, also identified as
§ 7 in this document. Therefore, although the EPA has not yet fully evaluated risks to federally
listed species, the agency will complete its listed species assessment and any necessary
consultation with the Services for irgarol prior to completing the irgarol registration review.
Likewise, the agency will complete endocrine screening for irgarol, pursuant to the Federal
Food, Drug, and Cosmetic Act (FFDCA) § 408(p), before completing registration review. See
Appendices C and D, respectively, for additional information on the listed species assessment
and the endocrine screening for the irgarol registration review.
The agency has been working with the International Maritime Organization (IMO) that is
proposing to ban cybutryne (irgarol). When the proposal to ban cybutryne (irgarol) was first
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considered at the I MO in 2017, the U.S. Coast Guard consulted with EPA offices (Office of
Chemical Safety and Pollution Prevention, Office of Water, and Office of International and
Tribal Affairs) and other federal agencies. Following consideration of the technical merit of the
proposal, current market demand and alternatives, and the anticipated support at the I MO for the
proposal, the Coast Guard - with concurrence from EPA and other federal agencies
- in 2019 expressed "no objection" to the recommendation to go forward with a comprehensive
proposal to a ban on the anti foul ant paint use. For further discussion on EPA's proposed strategy
to align with the IMO ban, see Section 111 C.
Irgarol, also referred to as cybutryne, (PC Code 128996) is used as an algaecide, fungicide,
antifouling agent, microbicide, microbiostat, molluscicide, and slimicide. Products containing
irgarol are registered for use as an anti foul ant paint on boat hulls and as a material preservative
in paints, caulks, coatings, sealants, grouts, vinyl roofing, roof coatings, cements, stucco, wood
stains, adhesives, plasters, and incorporated into boat hulls themselves.
This document is organized in five sections: thq Introduction, which includes this summary and a
summary of public comments and the EPA's responses; Use and Usage, which describes how
and why irgarol is used and summarizes data on its use; Scientific Assessments, which
summarizes the EPA's risk and benefits assessments, updates or revisions to previous risk
assessments, and provides broader context with a discussion of risk characterization; the
Proposed Interim Registration Review Decision, which describes the mitigation measures
proposed to address risks of concern and the regulatory rationale for the EPA's PID; and, lastly,
the Next Steps and Timeline for completion of this registration review.
A. Summary of Irgarol Registration Review
Pursuant to 40 CFR § 155.50, the EPA formally initiated registration review for irgarol
(l,3,5-Triazine-2,4-diamine, N -cy cl opropy 1 - NT - (1,1 -dimethylethyl )-6-(methylthio)-) also called
cybutryne, with the opening of the registration review docket for the case. The following
summary highlights the docket opening and other significant milestones that have occurred thus
far during the registration review of irgarol.
•	March 3 1, 2010 - The Irgarol Preliminary Work Plan (PWPJ, was posted to the docket
for a 60-day public comment period. No comments were made that impacted the schedule
or risk assessment needs.
•	September 2010 - The Final Work Plan (FWP) for irgarol was issued.
•	September 2014 GDC1-128996-1425 - A Generic Data Call-in (GDC1) for irgarol was
issued for data needed to conduct the registration review risk assessments. All data have
been submitted.
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•	February 2020 - The agency announced the availability of the Registration Review Draft
Risk Assessment for Irgar ol (also called Cybutryne) for a 60-day public comment period.
No public comments were received.
•	July 2020 - The Revised Inhalation Risk Assessment for the Irgarol Registration Review
DRA was completed. The inhalation risk assessment was revised to include the 90-day
inhalation toxicity study that was submitted after the irgarol draft risk assessment was
conducted. Based on the 90-day inhalation toxicity study, inhalation risks were reduced,
but not completely eliminated (See Sections 4 and 5 in the document). The revised
inhalation risk assessment document will be posted in the docket at the same time as the
proposed interim decision (P1D).
•	September 2020 - The agency has completed the Irgarol Proposed Interim Registration
Review Decision and will announce its availability in the Federal Register in the docket
for a 60-day public comment period.
II. USE AND USAGE
Irgarol containing products are currently registered for use in antifoulant paints for boat and/or
vessel hulls in both marine and freshwater settings; as a algicidal preservative in paints, caulks,
coatings, sealants, grouts, vinyl roofing, roof coatings, stucco, wood stains, adhesives, plasters;
and is incorporated into boat hulls themselves. In antifouling paints, irgarol is often combined
with copper, or copper compounds such as cuprous oxide or copper thiocyanate. While irgarol
effectively controls algae, copper is effective at controlling aquatic animals such as mussels and
barnacles. Irgarol is a s-triazine algaecide used in combination with copper in antifoulant paint as
a "booster" biocide, intended to diminish algae growth on ship hulls. In material preservative
products, irgarol is often combined with carbendazim (MBC), chlorothalonil, and/or DCOIT
(3(2H)-Isothiazolone, 4,5-dichloro-2-octy 1 -).
Currently, there are six registrants with 16 active products in this case; one is a technical product
and 15 are end-use products. The end use products are formulated as solid concentrate powders,
liquid concentrates, ready to use liquids (i.e., paints) and pressurized liquids (i.e., paints in spray
cans). Four of the end-use products are irgarol only and contain between 2 and 98.6% irgarol.
The other 1 1 are combinations of cuprous oxide + irgarol, cuprous oxide + carbendazim +
DCOIT or copper thiocyanate + irgarol containing between 0.8 and 3.5% irgarol. Ten end-use
products are antifoulant paint formulations that contain 0.49 to 2.38% irgarol. According to
Kline and Company (2016), irgarol (listed as triazine), accounted for 1.4%) of average market
pricing of selected antifoulant marine coatings in the US. According to Kline and Company
(2004), which lists irgarol specifically, the annual sales were 3.5 million dollars. Kline and
Company (2004) also indicated that irgarol is used primarily for yachts as a booster for copper
based marine antifoulant coatings. Although irgarol compounds are the least expensive active
among co-biocides, it is predicted to witness slow growth for issues related to high toxicity and
low biodegradability (2016).
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III. SCIENTIFIC ASSESSMENTS
A. Human Health Risks
A summary of the agency's human health risk assessment is presented below. The agency used
the most current science policies and risk assessment methodologies to prepare a risk assessment
in support of the registration review of irgarol. For additional details on the human health
assessment for irgarol, see the Irgarol Human Health and Ecological Draft Risk Assessment, and
the Irgarol Revised Inhalation Risk Assessment which are available in the public docket (EPA-
HQ-OPP-2010-0003) at www.regulations.gov.
1. Risk Summary and Characterization
Dietary (Food + Drinking Water) Risks
There are no human health risks from oral exposures to irgarol as there are no dietary uses or
drinking water or incidental oral exposures.
Residential Handler Risks
There was no inhalation risk of concern for anti foul ant paint use in the initial risk assessment or
revised inhalation risk assessment; however, dermal risks of concern were identified for
anti foul ant paint applied with a brush and roller. The margin of exposure (MOE) of 65 for
painting the largest size recreational boat (i .e., 30 ft long) without wearing gloves is of concern
because it is less than the target MOE of 100. Residential inhalation handler risks evaluated for
other smaller treated boats ranging from 14 ft to 20 ft long were greater than the MOE of 100
and not of concern.
Residential handler inhalation exposure risk was identified during the 'Do It Yourself (D1Y)
application rate of 3.94% irgarol as an algicidal preservative in paints. The MOE of 19 is of
concern because it is less than the level of concern (LOC) of 30 for both brush/roller and airless
sprayer methods of application.
Residential Post-Application Risks
There are no residential post-application risks of concern.
Occupational Handler Risks
Occupational handler inhalation risk was identified during the commercial application of irgarol -
containing anti foul ant paints applied to large vessels such as cargo ships, cruise ships and large
pleasure boats (i.e., mega yachts) that ranged between 90 to 680 ft. The inhalation exposures
were calculated as air concentrations using the average 8-hour time weighted average for each
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trial/job combination. The MOE of 15 applied by spray men is of concern for all large boat sizes
because it is less than the LOC of 30.
Occupational handler exposure risk was identified during the open pour powder addition of
irgarol as a preservative during paint manufacturing and commercial application of irgarol as an
algicidal preservative in paints. The product with the lowest application rate of 0.46% irgarol
(EPA Reg No.707-3 12) is not of concern since all MOEs are above the target MOE. The product
with the highest application rate of 3.94% irgarol (EPA Reg No. 40810-15) has the greatest risks
to occupational handlers for these uses. The inhalation MOEs of 0.6 for open pour powder to
preserve paints at 3.94% irgarol and 5.8 for airless spray application of paints containing 3.94%
irgarol, are of concern because they are less than the target MOE of 30. Occupational handler
dermal risks for airless spray application of paint containing 3.94% irgarol is of concern since the
MOE of 5 1 is less than the target MOE of 100.
Occupational Post-Application Risks
There are no occupational post-application risks of concern.
Aggregate Risks
There are no exposures via the oral route. Exposures to irgarol can occur via the inhalation and
dermal routes from anti foul ant paint used by D1Y boat painters and from algicidal preservative
paint used by residential painters. It is extremely unlikely that a residential painter would paint
their boat with irgarol anti foul ant paint and their house with irgarol preserved paint on the same
day; therefore, an aggregate risk assessment is not needed for irgarol.
Cumulative Risks
The EPA has not made a common mechanism of toxicity to humans finding as to irgarol and any
other substance (e.g., other S-triazines) and it does not appear to produce a toxic metabolite
produced by other substances. Therefore, the EPA has not assumed that irgarol has a common
mechanism of toxicity with other substances for this assessment.
2.	Human Incidents and Epidemiology
The search of the Incident Data System (IDS) did not include any reports in the database as of
August 2020. The agency will continue to monitor the incident information. Additional analyses
will be conducted if ongoing human incident monitoring indicates a concern.
3.	Tolerances
There are no tolerances, tolerance exemptions or FDA clearances for irgarol and none are
required for this P1D.
4.	Human Health Data Needs
The agency does not anticipate calling in any further data for irgarol.
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B. Ecological Risks
A summary of the agency's ecological risk assessment is presented below. The agency used the
most current science policies and risk assessment methodologies to prepare a risk assessment in
support of the registration review of Irgarol. For additional details on the ecological assessment
for irgarol, see the Registration review Irgarol Human Health and Ecological Draft Risk
Assessment which is available in the public docket at www.regulations.gov under docket ID
EPA-HQ-OPP-2010-0003.
The EPA is currently working with its federal partners and other stakeholders to implement an
interim approach for assessing potential risk to listed species and their designated critical
habitats. Once the scientific methods necessary to complete risk assessments for listed species
and their designated critical habitats are finalized, the agency will complete its endangered
species assessment for Irgarol. See Appendix C for more details. As such, potential risks for non-
listed species only are described below.
1.	Risk Summary and Characterization
The agency has determined that irgarol is highly toxic to freshwater fish, aquatic invertebrates
and both freshwater and marine plants. Leaching from paints applied to boat hulls will expose
aquatic organisms to parent irgarol and its primary triazine degradation product. Risks to aquatic
plants exceed the level of concern for non-listed species based on modeling using the
environmental fate data and median release rates of parent irgarol from treated paints in saltwater
environments. Because risks were identified for algae, it was determined that there is also a
potential for risk to coral from the antifouling paint use of irgarol. However, the modelled
exposure concentrations do not exceed any acute or chronic level of concern for fish or aquatic
invertebrates. Even though the use as a material preservative may result in leaching, a terrestrial
ecological risk assessment was not conducted because, treated building materials are spatially
dispersed and not expected to occur in any one concentrated area. Therefore, overall terrestrial
exposure is expected to be minimal, and irgarol is practically nontoxic to terrestrial receptors
(including pollinators).
2.	Ecological Incidents
The search of the Incident Data System (IDS) did not include any reports in the database as of
August 2020. The agency will continue to monitor ecological incident information as it is
reported to the agency. Detailed analyses of incidents are conducted if reported information
indicates concerns for risk to non-target organisms.
3.	Ecological and Environmental Fate Data Needs
The ecological and environmental fate database is complete, and no data is anticipated to be
called in at this time.
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C. International Maritime Organization (IMO) Environmental Actions for Irgarol
The IMO is the United Nations technical organization responsible for setting safety,
environmental, and other standards for international shipping.
The U.S. Coast Guard formally represents the U.S. Government in the work of the IMO. It
establishes U.S. negotiating positions in close consultation with EPA, National Oceanic
Atmospheric Administration (NOAA), Department of State, Navy, Maritime Administration
(M ARAD), Department of Justice, and other federal entities.
When the proposal to ban cybutryne (irgarol) was first considered at the IMO in 2017, the Coast
Guard consulted with EPA offices (Office of Chemical Safety and Pollution Prevention, Office
of Water, and Office of International and Tribal Affairs) as well as NOAA, Navy, Department of
State, Department of Transportation, and other federal entities. Following consideration of the
technical merit of the proposal, current market demand and alternatives, and the anticipated
support at the IMO for the proposal, the Coast Guard - with concurrence from EPA and other
federal entities - in 2019 expressed "no objection" to the recommendation to go forward with a
comprehensive proposal to a ban on the antifoulant paint use.
During the discussions of the proposal at IMO meetings, the Coast Guard and NOAA
representatives noted strong support, even among industry entities, for the recommended
ban. EPA's subsequent conversations with industry counterparts, e.g., the American Coatings
Association, confirmed that industry agreed that the IMO's risk assessment was rigorous and
well done and that industry groups do not oppose the ban.
1. IMO Timeline
The recommended IMO timeline1 for the ban on use of irgarol as an antifoulant paint is still
tentative and shifting. The proposed date for prohibition of new applications of irgarol is
currently scheduled to be effective as of October 2025 and the requirement for sealing of
existing irgarol-containing coatings after October 2030. The agency has been in communication
with all the irgarol registrants, and they concur with the cancellation of their antifoulant paint
uses of irgarol, preferably along the same timelines of the IMO (See Section IV for proposed
mitigation).
D. Alternative Antifoulant Active Ingredients
Without the protection of an effective antifoulant paint coat, a boat may be subject to biofouling,
that is, the hull may become colonized by algae, barnacles, or similar species. A boat that is
biofouled will consume more energy and fuel to propel it through the water due to increased
drag. Aside from the costs to boat owners, this also increases fuel-related pollution. In cases of
1 http://wwwimo.org/en/MediaCentre/MeetingSumiiiaries/MEPC/Pases/MEPC-74th-session.aspx
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excessive fouling, damage to the hull and moving parts of the boat such as propellers is expected
to occur. Additionally, the maneuverability and performance of the boat is impaired, creating
safety concerns. The severity of fouling varies greatly with water temperature, salinity, pH,
nutrient content and geographic region all playing a role. As an ecological concern, biofouled
boats that travel to different marinas may cause recreational boaters to unknowingly transport
invasive species.
It is estimated that approximately one-third of the U.S. adult population participates in
recreational boating annually (combining both freshwater and saltwater uses). Recreational boats
comprise the U.S.' largest boat fleet, far outnumbering U.S. merchant shipping, commercial
fishing, passenger traffic, and Armed Services fleets. The agency does not have data to indicate
the percentage of recreational boaters who use antifoulant products but assumes this is a large
proportion of boaters. The irgarol registrants have identified zinc pyrithione, tralopyril and
DCOIT as alternatives. Table 1 provides a comparison of antifoulant paint and coatings.
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Table 1: Comparison of Antifoulaiit Paint and Coatings
Tvpe of Paint
Description
Frequencv of
Application
(appro*.)'
Advantages
Disadvantages
Cuprous oxide (Case
4025, PC Code
025601)2
Coppcr-bascd
biocidc
2-3 years
Low in cost
Widely available
Broad-spectrum biocidc
No human health risks of concern
Toxicant to non-target aquatic species
Copper persists in environment
Irgarol
(Case 5031,
PC Code
128996)2
Organic algicide
< 2 years
Effective against algae
Slower leach rate than
other biocidcs listed in
table based on median
of release rates
Human health and ecological risks of
concern
Ecological risk to non-target aquatic plants
and coral
Must be combined with other antifoulaiit
DCOIT (Case
5023, PC Code
128101)2
Organic, metal-
free biocidc
< 2 years
Broad-spectrum biocidc
Low VOC4 emissions
Docs not persist in environment
Minimal bioaccuniulation
Stripping of old paint not required
Human health and ecological risks of concern
Requires professional application
More frequent application required
Zinc pyrithione
(Case 2480, PC
Code 088002)2
Zinc-based
biocidc
<2 years
Broad-spcctrum biocidc
Human health risks arc being reevaluated. "
Toxicant to non-target aquatic species
Pyrithione persists in environment
More frequent application required
More coats of paint required
Econea™/Tralopy
ril (Case 5114.
PC Code
119093)2
Organic, metal-
free biocidc
< 2 years
Docs not persist in environment
Effective against macro fouling
Human health and ecological risks of concern
More frequent application required
Must be combined with other antifoulaiit
Silicone antifoulaiit
coatings
(Case: N/A, PC
Code: N/A)
Soft non-biocidc
5-10 years
Longevity
Scrubbing, dry docking docs not compromise
effectiveness
Broad-spectrum effectiveness
Can be cleaned at same frequency as copper
More expensive up-front cost
Stripping off old paint layer required
Not widely available
Toxicity not evaluated by the agency
Not a registered antimicrobial antifoulaiit use.
Epoxy antifoulaiit
coatings
(Case: N/A, PC
Code: N/A)
Hard non-biocidc
5-10 years
Longevity
Scrubbing, dry docking docs not compromise
effectiveness
Broad-spcctrum effectiveness
More expensive up-front cost
Stripping off of old paint layer required
Not widely available
Require more frequent cleaning
Toxicity not evaluated by the agency
1 The lifespan of any AFC system is subject to the conditions in which the craft is used and frequency of hull cleaning, thus an approximate range is provided.

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2	Currently undergoing registration review.
3	This case docs not have a completed risk assessment for registration review; thus, the agency has not made a risk determination. Human health studies have
been identified as necessary to assess safety for paint applicators (occupational and residential handlers).
4	Volatile Organic Compound
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IV. PROPOSED INTERIM REGISTRATION REVIEW DECISION
A. Proposed Risk Mitigation and Regulatory Rationale
In evaluating potential risk mitigation for the applications of irgarol, the agency has considered
the risks and benefits. EPA has determined that there are human health and ecological risks of
concern from the use of irgarol in anti foul ant paints, preserved paint, and as a materials
preservative. However, the agency has also identified areas where risk mitigation measures are
appropriate and is proposing to implement label changes for anti foul ant paints and preserved
paints containing irgarol. Mitigation measures are expected to greatly reduce human health and
ecological risks of concern from the use of irgarol in antifoulant and preserved paints. The
agency has notified registrants of the proposed mitigation measures to address the risks of
concern and the registrants are in general agreement with the agency's proposed mitigation.
1.	Proposed Removal of Antifoulant Paint Uses for Irgarol
To mitigate occupational handler inhalation and dermal human health risk as well as the
freshwater and marine ecological exposure risks to aquatic plants that affect coral reefs, the
agency is proposing to remove the antifoulant paint use of irgarol. The agency has been working
with the registrants who are planning to cancel their antifoulant paint uses of irgarol along the
same timelines of the I MO (see Section lll.C). EPA understands the most recent IMO
recommendation is to ban the use of irgarol (cybutryne) as an antifoulant paint with no new
applications as of October 2025 and no existing irgarol-containing coatings after October 2030
unless sealed. Therefore, the agency is proposing that registrants with product labels that include
marine and freshwater antifoulant paints uses must request removal of those uses by September
30, 2023. If the products are only registered for antifoulant paint uses, then registrants must
submit a voluntary cancellation request by September 30, 2023. The timing for the FIFRA 6(f)
process and allowing for use of existing stocks is estimated to take 2 years; therefore, the
antifoulant paints uses will be effectively cancelled by October 2025, which aligns with current
IMO recommendations. Once all labels are received, the agency will use its FIFRA 6(f) authority
to officially cancel the antifoulant paint uses.
The agency would like stakeholder feedback on this proposed timeframe during the comment
period for this PID.
2.	Proposed Occupational and Residential Handler Mitigation for the Airless
Sprayer Application of Algicidal Preserved Paint for Irgarol
To mitigate the potential inhalation and dermal risks for both residential and occupational
handlers applying irgarol-preserved paints via airless sprayer, the agency is proposing to lower
the maximum allowed application rate to 0.76 % a.i. by weight. This rate is not the lowest level
of 0.046% found in the revised risk assessment2; however, it is low enough to mitigate the
painter risks. This paint product is useful for building materials, stucco, sealants, and coatings.
2 Revised Inhalation Risk Assessment for the Irgarol Registration Review DRA. July 16, 2020.

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3. Proposed Occupation Handler Mitigation for the Open Pouring of Irgarol
Powder Formulations.
The agency is proposing water-soluble packaging for powder formulations of irgarol to mitigate
dermal and inhalation risks of concern.
B.	Tolerance Actions
There are no tolerances or exemptions from the requirement of tolerances required for irgarol.
C.	Proposed Interim Registration Review Decision
In accordance with 40 CFR §§ 155.56 and 155.58, the agency is issuing this PID. Except for the
Endocrine Disruptor Screening Program (EDSP) and the Endangered Species Act (ESA)
components of this case, the agency has made the following PID: (1) no additional data are
required at this time; and (2) changes to the affected registrations and their labeling are required
at this time, as described in Section IV. A and Appendices A and B.
In this PID, the agency is making no human health or environmental safety findings associated
with the EDSP screening of irgarol, nor is it making a complete endangered species finding.
Although the agency is not making a complete endangered species finding at this time, the
proposed mitigation described in this document is expected to reduce the extent of environmental
exposure and may reduce risk to listed species whose range and/or critical habitat co-occur with
the use of irgarol. The agency's final registration review decision for irgarol will be dependent
upon the result of the agency's ESA assessment and any needed § 7 consultation with the
Services and an EDSP FFDCA § 408(p) determination.
D.	Data Requirements
The agency does not anticipate calling-in additional data for registration review of irgarol.
V. NEXT STEPS AND TIMELINE
A. Proposed Interim Registration Review Decision
A Federal Register Notice will announce the availability of this PID for irgarol and will allow a
60-day comment period. If there are no significant comments or additional information
submitted to the docket during the comment period that leads the agency to change its PID, the
EPA may issue an interim registration review decision for irgarol. However, a final decision for
irgarol may be issued without the agency having previously issued an interim decision. A final
decision on the irgarol registration review case will occur after: (1) an EDSP FFDCA § 408(p)
determination, and (2) an endangered species determination under the ESA and any needed § 7
consultation with the Services.
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B. Implementation of Mitigation Measures
Once the Interim Registration Review Decision is issued, the irgarol registrants must submit
amended labels (except anti foul ant uses, see below) that include the label changes described in
Appendices A and B. The revised labels and requests for amendment of registrations must be
submitted to the agency for review within 60 days following issuance of the Interim Registration
Review Decision in the docket.
The agency is proposing that registrants with product labels that include marine and freshwater
antifoulant paints uses must request removal of those uses by September 30, 2023. If the
products are only registered for antifoulant paint uses, then registrants must submit a voluntary
cancellation request by September 30, 2023.
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Appendix A: Summary of Proposed Actions for Irgarol
Registration Review
Case#: 5031
PC Code:
128996
Chemical Type: antifoulant, microbicide, molluscicide, slimicide, fungicide
Affected Population(s)
Source of Exposure
Route of
Exposure
Duration of
Exposure
Potential Risk(s) of
Concern
Proposed
Actions
Residential Handler
Airless Sprayer
Application of
paint
Inhalation
Dermal
Short
Upper respiratory tract
irritation
Irritation
Decrease Application Rate
Occupational Handler
Airless Sprayer
Application of
paint
Inhalation
Dermal
Short
Intermediate
Upper respiratory tract
irritation
Irritation
Decrease Application Rate
Occupational Handler
Open pour powders
Open pouring of
powders to
preserve paints
Inhalation
Short
Intermediate
Upper respiratory tract
irritation
Water-Soluble packaging
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Residential Handler
Brash and roller
Application of
antifoulant paint
Dermal
Short
Irritation
Cancel the antifouling paint
use
Occupational Handler
Application of
antifoulant paint
Inhalation
Dermal
Short
Intermediate
Upper respiratory tract
irritation
Irritation
Cancel the antifouling paint
use
Aquatic Plants (and
indirectly Corals)
Leaching of
antifoulant paint
Leaching
Acute
Sub-chronic
Chronic
Risks to aquatic plants
and coral bleaching
Cancel the antifoulant paint
use
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Appendix B: Propose Labeling Changes for Irgaro! Products
Description
Proposed Label Language for Irgaro! Products
Placement on Label
Lower the
application rates
for formulated
algicidal paints,
coatings, stucco,
stains and caulks to
inhibit or control
the growth of algae
on the treated
formulations
The maximum allowed application rate is 0.76 % irgarol by weight.
Directions for Use
Formulated
powders put into
water-soluble
packages
Water-soluble packaging is required for powder formulations.
Directions for Use
Removal of the
antifoulant paint
uses for ecological
risks and
occupational and
residential handler
risks
Antifoulant paint uses must be removed from labels by submitting a label amendment to the agency by September 30,
2023. Products that arc only registered for antifoulant paints uses must request voluntary cancellation by September 30,
2023.
N/A
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Appendix C: Endangered Species Assessment
In 2013, EPA, along with the Fish and Wildlife Service (FWS), the National Marine Fisheries
Service (NMFS), and the United States Department of Agriculture (USDA) released a summary
of their joint Interim Approaches for assessing risks to endangered and threatened (listed) species
from pesticides. These Interim Approaches were developed jointly by the agencies in response to
the National Academy of Sciences" (NAS) recommendations that discussed specific scientific
and technical issues related to the development of pesticide risk assessments conducted on
federally threatened and endangered species.
Since that time, EPA has conducted biological evaluations (BEs) on three pilot chemicals
representing the first nationwide pesticide consultations (final pilot BEs for chlorpyrifos,
malathion, and diazinon were completed in January 2017). These initial pilot consultations were
envisioned to be the start of an iterative process. The agencies are continuing to work to improve
the consultation process. For example, after receiving input from the Services and USDA on
proposed revisions to the pilot interim method and after consideration of public comments
received, EPA released an updated Revised Methodfor National Level Listed Species Biological
Evaluations of Conventional Pesticides (i.e.. Revised Method) in March 2020.3 During the same
timeframe, EPA also released draft BEs for carbaryl and methomyl, which were the first to be
conducted using the Revised Method.
Also, a provision in the December 2018 Farm Bill included the establishment of a F1FRA
Interagency Working Group (IWG) to provide recommendations for improving the consultation
process required under section 7 of the Endangered Species Act for pesticide registration and
Registration Review and to increase opportunities for stakeholder input. This group includes
representation from EPA, NMFS, FWS, USDA, and the Council on Environmental Quality
(CEQ). Given this new law and that the first nationwide pesticide consultations were envisioned
as pilots, the agencies are continuing to work collaboratively as consistent with the congressional
intent of this new statutory provision. EPA has been tasked with a lead role in this group, and
EPA hosted the first Principals Working Group meeting on June 6, 2019. The recommendations
from the IWG and progress on implementing those recommendations are outlined in reports to
Congress.4
Given that the agencies are continuing to work toward implementation of the Revised Method to
assess the potential risks of pesticides to listed species and their designated critical habitat, the
ecological risk assessment supporting this P1D for irgarol 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 this P1D, EPA's evaluation assumed, for all tax a of non-target wildlife and plants,
that listed species and designated critical habitats may be present in the vicinity of the
application of irgarol. This will allow EPA to focus its future evaluations on the types of species
3	https://www.regulations.gov/document?D=EPA-HQ-OPP-2019-0185-0084
4	https://www.epa.gov/endangered-species/reports-congress-improving-consultation-process-under-endangered-
species-act
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where the potential for effects exists once the Revised Method has been fully implemented. Once
that occurs, the Revised Method will be applied to subsequent analyses for irgarol as part of
completing this registration review.
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Appendix D: Endocrine Disrupter Screening Program
As required by FIFRA and FFDCA, the EPA reviews numerous studies to assess potential
adverse outcomes from exposure to chemicals. Collectively, these studies include acute, sub-
chronic 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, the 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 irgarol,
the 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
§408(p), irgarol is subject to the endocrine screening part of the Endocrine Disruptor Screening
Program (EDSP).
The 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 1 1 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 the
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 § 408(p), the agency must screen all pesticide chemicals. Between October 2009
and February 2010, the EPA issued test orders/data call-ins for the first group of 67 chemicals,
which contains 58 pesticide active ingredients and 9 inert ingredients. The agency has reviewed
all of the assay data received for the List 1 chemicals and the conclusions of those reviews are
available in the chemical-specific public dockets. A second list of chemicals identified for EDSP
screening was published on June 14, 2013,5 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. 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 the EPA website.6
In this P1D, the EPA is making no human health or environmental safety findings associated with
the EDSP screening of irgarol. Before completing this registration review, the agency will make
an EDSP FFDCA § 408(p) determination.
5	See http://www.regulations.gov/#!documentDetail;D=EPA-HO-OPPT-2009-0477-0074 for the final second list of
chemicals.
6	https://www.epa.gov/etidocritie-disRiptioti
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