Docket Number: EPA-HQ-OPP-2011-0611 

www .regulations.gov 

Sodium Pyrithione 

Amended Final Work Plan 

Registration Review 

Case Number: 0209 

Approved By: 

Acting Director, Antimicrobials Division 

Date: 
Docket Number: EPA-HQ-OPP-2011-0611 

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2 

Sodium Pyrithione AMENDED FINAL WORK PLAN 

Introduction

This document amends the Final Work Plan (FWP) for the registration review of Sodium 

Pyrithione. Since the publication of the June 2012 Final Work Plan, the Agency has determined 

that certain data requirements identified to support the registration review of sodium pyrithione 

in the Ecological Environmental Scoping Document were inadvertently omitted in the FWP. 

This document amends the June 2012 FWP to include the following studies among the data 

identified as needed for registration review: 

• 850.1075: Acute fish toxicity (Rainbow trout, Tier II) 

• 850.1300: Invertebrate life cycle test (freshwater) 

• 850.1400: Fish early life-stage test (Rainbow trout) 

• 850.4400: Aquatic Plant Test using Lemna sp. 

• 835.1110: Activated Sludge Sorption Isotherm 

Unless otherwise stated by the Agency, all other elements of the Agency's June 2012 Sodium 

Pyrithione FWP remain unchanged. 
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Summary of Data Requirements

A summary table of the data required to support the registration review of Sodium Pyrithione is 

presented below.

Data Requirements for the Registration Review of Sodium Pyrithione (PC Code 088004) 

Guideline 

Number Anticipated Data Requirement Test Material 

Estimated Timeframe 

(Measured in months 

from DCI receipt) 

835.2240 Photodegradation in Water TGAI 12 

850.10751 Acute fish toxicity (Tier II) TGAI 12 

850.1300 Aquatic invertebrate life cycle test (freshwater) TGAI 12 

850.14002 Fish early-life stage toxicity test, freshwater species TGAI 12 

850.44003 Aquatic Plant Test using Lemna sp., Tier II TGAI 12 

850.45004 Algal Toxicity Tier II -- marine diatom, freshwater 

diatom, green algae TGAI 12 

850.45504 Algal Toxicity Tier II – Cyanobacteria TGAI 12 

875.1200 Dermal indoor exposure TGAI 24 

875.1400 Inhalation indoor exposure TGAI 24 

875.1600 Application exposure data reporting and calculations TGAI 24 

875.1700 Product use information TGAI 12 

875.2300 Indoor surface residue dissipation TGAI 24 

850.33005 Activated Sludge Respiration Inhibition TGAI 12 

835.11106 Activated Sludge Sorption Isotherm TGAI 12 

835.31107 Ready Biodegradability TGAI 12 

835.32207 Porous Pot Test TGAI 12 

835.32407 Simulation Test – Aerobic Sewage Treatment: A. 

Activated Sludge Units TGAI 12 

835.32807 Simulation Tests to Assess the Biodegradability of 

Chemicals Discharged to Wastewater TGAI 12 

 

1

 Results from a Tier II study using Rainbow Trout must be submitted to satisfy this requirement. 2

 Results from a study using Rainbow Trout must be submitted to satisfy this requirement. 

3

 If the IC50 for the freshwater green alga, Selenastrum capricornutum is greater than 1000 ppb, the Agency would 

consider waiving data for the aquatic non-vascular plant test. 

4

 Results for studies conducted with the TGAI for (i) the freshwater green alga, Selenastrum capricornutum, (ii) the 

freshwater diatom, Navicula pelliculosa, (iii) the marine diatom, Skeletonema costatum, and (iv) the cyanobacteria 

species Anabaena flos-aquae, must be submitted to satisfy this requirement. Final 850 guidelines for the algal 

testing were posted in June 2012 after posting of the FWP. The Public Draft OPPTS 850.5400 Algal Toxicity 

guideline was split into two separate guidelines and renumbered with the cyanobacteria species separated into 

OCSPP 850.4550 and the other three species under OCSPP 850.4500. If the IC50 for the freshwater green alga, 

Selenastrum capricornutum is greater than 1000 ppb, the Agency would consider waiving data for the three other 

algal species. 

5

 EPA has a published final guideline for this study. The Agency anticipates codifying this study in 40 CFR 158(W) 

in the near future. OECD Test Guideline 209 can also be used as guidance for this study, available online at 

http://www.oecd-ilibrary.org/content/book/9789264070080-en . 6

 EPA has a published final guideline for this study. The Agency anticipates codifying this study in 40 CFR 158(W) 

in the near future. 

7

 EPA has published final guidelines for four biodegradation studies. The biodegradation study required for Sodium 

Pyrithione is based on results of an Activated Sludge Respiration Inhibition test. The Agency anticipates codifying 

these studies in 40 CFR 158(W) in the near future. 
United States Chemical Safety June 2012

Environmental Protection and Pollution Prevention

Agency (7510P)

Sodium Pyrithione

(Sodium Omadine)

Registration Review:

Final Work Plan

June 2012

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Sodium Pyrithione Registration Review Team

Human Health & Environmental Effects

Timothy Dole

Srinivas Gowda

James Breithaupt

David Bays

Risk Management

Wanda Henson

Lance Wormell

Office of General Counsel

Philip Ross

________________________________________

Supporting documents for the Sodium Pyrithione Case may be found in the registration review 

docket EPA-HQ-OPP-2011-0611 located on the internet at www.regulations.gov.
Docket Number: EPA-HQ-OPP-2011-0611

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Introduction

This is the Final Work Plan (FWP) of the Environmental Protection Agency (EPA or “the 

Agency”) for the registration review of Sodium Pyrithione (Case 0209). The work plan includes 

the expected registration review timeline. The work plan also addresses public comments

received concerning the Preliminary Work Plan (PWP) in the Summary Document which was 

posted in the Sodium Pyrithione registration review docket, and any other comments concerning

the initial docket postings. The Summary Document provided information on what EPA knows 

about the pesticide and what additional risk analyses and data or information the Agency 

believes are needed to make a registration review decision.

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. Changes in science, public policy and pesticide use practices will occur over time. 

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 that 

statutory standard. The public phase of registration review begins when the initial docket is 

opened for each case. Information on this program is provided at: 

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

The Sodium Omadine Preliminary Work Plan (PWP) (PC Code 088004) was published on

December 21, 2011 and the 60-day comment period ended on February 21, 2011. This case was 

originally titled “Sodium Omadine” and has since been renamed “Sodium Pyrithione” to replace 

the trade name “Omadine” with the generic active ingredient name, “pyrithione.” The 

Preliminary Work Plan document is available on www.regulations.gov docket number EPA-HQOPP-2011-0611.

The first product containing sodium pyrithione (PC Code 088004) as an active ingredient was 

registered in the United States in 1968. Currently, there are 12 products containing sodium 

pyrithione as an active ingredient registered with EPA. They are used in metalworking cutting 

fluids, cooling and lubricating fluids, adhesives, caulks, patching compounds, sealants, pastes 

and grouts, paints (in-can), inks, sponges, janitorial products (in-container), hides/leather /leather 

products (surfaces), aqueous analytical and diagnostic reagents used in chemical and clinical 

analysis, aqueous synthetic fiber lubricating (spin finishes), carrageenan based gels used in solid 

air fresheners, dry wall and gypsum, pearlite, plaster-like, mineral used in manufacture of tile, 

chrome or vegetable tanned leather, for the dry film preservation of natural, and synthetic 

adhesives, latexes, urethane foams, caulks, patching compounds, sealants, architectural paints, 

industrial paints and coatings (including wood coatings), glues, in-can preservation of latex 

emulsions used in adhesives, laundry rinse additives, laundry detergents, carpet cleaners, surface 

cleaners, floor cleaners, pigment slurries, building materials such as joint cements and concrete 

additives, materials in the textile, paper, polishes waxes, protein solutions, ceramic glazes, fire 

extinguishing materials, cleaning solutions and detergents as a materials preservative. There are 

no tolerances or exemptions from tolerances established by the EPA for sodium pyrithione. 

Sodium pyrithione is approved by FDA as a preservative of adhesives in food contact packaging 

(21 CFR 175.105).
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The Agency completed a Reregistration Eligibility Decision (RED) for Sodium Omadine in 

1996. 

Comments Received on the Preliminary Work Plan

The Agency received two comments during the public comment period on the initial docket, 

described below. In the PWP, the Agency solicited comments on specific topics: environmental 

justice, water body impairment, trade irritants, and structure activity relationships. No comments

or information were received during the public comment period concerning these issues.

COMMENT #1: The registration review case name should be changed to the common 

chemical name - Sodium Pyrithione. OMADINE is a trade name of one of the registrants. 

In addition, all future registration review documents should reflect the common name 

rather than by tradenames, except when it is appropriate as in product brand names.

RESPONSE #1: Case 0209 has been renamed to "Sodium Pyrithione" and future 

documents associated with this registration review will refer to the generic active 

ingredient name, sodium pyrithione.

COMMENT # 2: The footnotes related to the environmental fate testing schemes are 

confusing and could be further clarified. Some specific points are below. i. The footnotes 

speaks of a Modified ASRI study but the footnote mentions just ASRI (not modified). 

Are they the same test and GLN? ii. GLN 835.3280 – Simulation Tests to the 

Biodegradability of Chemicals Discharged to Wastewater is one of the EFATE studies in 

the list of studies, but is not mentioned at all in the footnotes, so it unclear when required 

and how this fits in. iii. The footnote mentions a Biodegradation in Activated Sludge 

study, but this study is not one of those mentioned in the EFATE list of studies needed, 

and there is no Guideline number associated with that study. iv. One of the criteria for the 

second level of testing is whether the EC50 test result from the ASRI study is < or > 20 

mg/L, but except for Ready Biodegradability study for > 20 mg/L the tests are all the 

same. v. It is mentioned that if a Ready Biodegradability study is conducted and the 

product passes then no further testing is required. For antimicrobial chemicals which 

have activity vs microbes it makes more sense to test directly in one of the other 3 

EFATE test options. Is the ready biodegradability a required study or just one of the 4 

options if test results for ASRI giving EC50 > 20 mg/L.

RESPONSE #2: i). EPA has updated the anticipated data requirements to correctly 

reflect the need for the ASRI study rather than the the Modified ASRI study.” ASRI 

(OECD 209) and Modified ASRI for Sparingly Soluble Chemicals (OCSPP 850.6800) 

are similar tests. OCSPP 850.6800 is a modification of OECD 209 that can be used for 

test substances that are not soluble enough to make concentrated stock solutions in water. 

In that case, the test substance can be added directly to individual test vessels or 

alternatively, as a concentrated stock solution in an organic solvent. 

ii) Guideline 835.3280 has five parts. Only one part is required: “314B: Biodegradation 

in Activated Sludge”. In referring to “(ii) Biodegradation in Activated Sludge” in the 

footnote, the Agency is referring to the part of 835.3280 that is required (i.e., 314B: 
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Biodegradation in Activated Sludge). Guideline numbers associated with choices in the 

footnote are as follows:

a. The result of the ASRI EC50 is less than or equal to 20 mg/L, then one of three 

biodegradation simulation tests (835.3220, 835.3280, or 835.3240) will be 

required.

b. The result of the ASRI EC50 is above 20 mg/L, then either a Ready 

Biodegradability test (835.3110) or one of the above three biodegradation 

simulation tests (835.3220, 835.3280, or 835.3240) will be required. If the 

Ready Biodegradability test (835.3110) is run and the result is negative, then 

one of the three biodegradation simulation tests (835.3220, 835.3280, or 

835.3240) is also required.

iii) See response to ii above.

iv) The commenter is correct that, with the exception of the Ready biodegradability test, 

the choice of biodegradation studies is the same whether the results for the ASRI test is 

less than or equal to 20 mg/L or is greater than 20 mg/L. The same biodegradation 

information is needed for both cases. However, to provide flexibility for those test 

substances known to be relatively nontoxic to activated sludge microbes and suspected to 

be readily biodegradable an option to by-pass the biodegradation simulation testing is 

provided in the form of the Ready Biodegradability test. If toxicity of the test substance 

to activated sludge microbes is such that the EC50 is >20 mg/L, there is an option to first 

conduct a Ready Biodegradability test rather than one of the three biodegradation 

simulation tests. If the Ready Biodegradability test passes, there is no need to conduct a 

biodegradation simulation test. Only if the test substance fails the Ready 

Biodegradability test is a biodegradation simulation test required. Alternatively, under 

this option the registrant can choose to by-pass the Ready Biodegradability option and 

conduct one of the three full biodegradation simulation tests.

v) See response to iii above.

COMMENT # 3: The formulation types are not consistently categorized amongst all the 

products. 43813-48 and 87772-2 are also ready-to-use solutions like 1258-843. Products 

43813-49 and 87772-1 are manufacturing concentrates, not a technical chemical or 

formulation intermediate, respectively.

RESPONSE #3: The information presented in Table 1, Registered Products - Sodium 

Pyrithione, is based on information from EPA files. If you believe EPA's information is 

incorrect or outdated, please submit a written request for updates to the EPA Product 

Manager or Chemical Review Manager along with any supporting documentation needed 

to verify the request.

COMMENT # 4: The TGAI is listed as the test material on page 18, Table 2. The 

product chemistry section mentions testing on a 97% technical material, however there is 

no registered technical grade product (see comment 3 above) as most/all products are 
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likely formulated by an integrated process. The most appropriate test material is the 40-

42% products. 

RESPONSE #4: In the case of sodium pyrithione, the Agency would prefer testing be 

conducted with the highest purity technical grade material. This obviates the need for 

duplicate data development for each technical grade active ingredient product unless 

there are unique TGAI impurities that also need to be considered in the effects testing.

COMMENT #5: The Agency is aware of the existence of the Antimicrobial Exposure 

Assessment Task Force II (AEATF II) and the conduct of a liquid pour study by the 

AEATF II and planning of the paint and metal working fluid (MWF) exposure studies. 

Does the Agency plan to accept the liquid pour study for the treated materials mentioned 

(paints, MWF, household cleaners)? AEATF has not envisioned incorporating a separate 

“pour” study into either the MWF or paint studies

RESPONSE #5: The study was designed for liquid pour scenarios and EPAanticipates 

that the results of the study will satisfy the data requirement. Once the AEATF study is 

submitted it will be reviewed by the EPA and Human Studies Review Board (HSRB) to 

determine whether or not the study is acceptable for use in EPA risk assessment.

COMMENT #6: For surface residue dissipation and leaching studies, does the Agency 

view one of the scenarios for each as worst case (dissipation from dishes, floors, carpets, 

or leaching from leather or textiles) to run a single study? 

RESPONSE #6: Residue data are needed for dishes, floors, carpets, and textiles. If the 

registrant believes the results of a single study can represent all of these uses, a written 

justification must be submitted to the Agency for review prior to initating the study. The 

justification should include an explanation of why one study could represent the uses 

intended to be assessed and details of the proposed study (e.g., which use has the high 

concentration, which application technique (e.g., surface application versus impregnated) 

will result in the most residue transfer, which surface will transfer the most residue). 

COMMENT #7: October 12, 2011 Memorandum – The executive summary mentions 

the need for textile and leather leaching studies but table 5, page 13 mentions surface 

residue dissipation studies for textiles and leaching. This should be clarified as these are 

different study types.

RESPONSE #7: The leaching studies in the executive summary and the surface residue 

dissipation studies in the body of the document refer to the same studies.

COMMENT # 8: If photodegradation data show that sodium pyrithione dissociates at 

low levels, existing environmental fate data using other Omadine salts should be 

bridgeable to fulfill the environmental fate data requirements for 850.6800, 835.3220, 

835.3280, 835.3240, 835.3110.

RESPONSE #8: Photodegradation testing results have no bearing on the Agency’s 

decision to require wastewater treatment plant tests (i.e., Activated Sludge Respiration 

Inhibition (ASRI; 850.6800 or OECD 209); Activated Sludge Sorption Isotherm (ASSI; 
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835.1110); and wastewater treatment plant biodegradation (835.3110 or 835.3220 or 

835.3280 or 835.3240)) nor do they inform the Agency’s decision on whether or not to 

bridge data from one pyrithione and/or its degradates to another pyrithione and/or its 

degradates.

The comments received during the initial public comment period did not affect the data needs, 

work plan and timeline described in the PWP and they remain as they were presented initially in 

the PWP. Further, this document makes final the work plan for the Sodium Pyrithione

registration review process.

Risk Assessments and Anticipated Data Needs

The Agency will conduct a comprehensive ecological risk assessment, including an endangered 

species risk assessment, for all uses of sodium pyrithione. The Agency will conduct a human 

health risk assessment for sodium pyrithione. The Agency expects to require additional data for 

use in conducting the registration review for sodium pyrithione.

Ecological Risk Assessment Status and Anticipated Data Needs

No recent ecological risk assessment has been performed for Sodium Pyrithione.

The Agency anticipates the need to require the following additional ecological data for use in 

conducting the registration review of Sodium Pyrithione.

850.5400 -- Algal Toxicity (Tier II) using freshwater green alga, Selenastrum 

capricornutum.

The Agency anticipates the need to require the following additional environmental fate data 

for use in conducting the registration review of Sodium Pyrithione.

835.2240 -- Photodegradation in water

850.6800 -- Activated sludge, respiration inhibition test

835.3110 -- Ready Biodegradability1

835.3220 – Porous Pot Test1

835.3280 -- Simulation Tests to Assess the Biodegradability of Chemicals Discharged 

to Wastewater1

835.3240 – Simulation Tests – Aerobic Sewage Treatment: A. Activated Sludge 

Units1

 

1 The results of the Activated Sludge Respiration Inhibition Test (ASRI) will determine which of these four 

biodegradation tests will be required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the (i) 

Biodegradation in Activated Sludge Study or (ii) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge 

Units or (iii) the Porous Pot Test would be required. If the ASRI test EC50 is greater than 20 mg/L, then the 

registrant can choose to conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or 

b) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready 

Biodegradability study is conducted and passes, then no further testing is required. If, however, the antimicrobial 

fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test –

Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study is required.
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For more information, please refer to Product Chemistry, Environmental Fate, and 

Ecological Effects Scoping Document in Support of Registration Review of Sodium 

Pyrithione, located in the docket.

Human Health Risk Assessment Status and Anticipated Data Needs

No recent human health risk assessment has been performed for sodium pyrithione.

Dietary Assessment

Most of the labels have the statement “Do not use for applications involving direct or indirect 

food/drinking water contact.” Three labels (#1258-990, #1258-1205 and #39967-26) do not 

have this statement; however, and label #39967-26 is approved for uses such as paper, 

cleaning solutions and detergents that might involve food contact. Sodium Pyrithione is also 

approved by FDA as a preservative of adhesives in food contact packaging (21 CFR 

175.105). Given these approvals, it will be necessary to assess indirect food contact 

exposures from these uses and residue data will be needed.

The registered uses of Sodium Pyrithione might result in contamination of surface and 

ground water as a result of discharges of treated water from industries using this 

antimicrobial as a material preservative. Therefore, drinking water exposure might occur. 

However, the need for a drinking water exposure assessment will be determined upon review 

of the environmental fate data that the Agency anticipates requiring. These data will be used 

to determine if Sodium Pyrithione can pass through wastewater treatment plants into drinking 

water. Therefore, the need for a drinking water assessment will be revisited upon submission 

and review of the environmental fate data.

Tolerances and International Harmonization

There are no tolerances or exemptions from tolerances established by the EPA for sodium 

pyrithione. Sodium pyrithione is approved by FDA as a preservative of adhesives in food 

contact packaging (21 CFR 175.105).

Occupational and Residential Assessment and Risk

Occupational post application exposures that occur during the use of treated materials were 

not assessed for the RED because it was believed at the time that these exposures would be 

minimal because of low application rates and because Sodium Pyrithione has low vapor 

pressure. Although it is true that vapor exposures to Sodium Pyrithione will be minimal as 

stated in the RED, there is the potential for dermal and inhalation exposures to aerosols 

during the use of materials such as paints, metal working fluids, surface cleaners and floor 

cleaners treated with Sodium Pyrithione. In addition, it will be necessary to reassess the 

general preservative uses because some materials have application rates of up to 5000 ppm 

which is much greater than the rate of 46 ppm that was assessed in the RED.
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Sodium pyrithione residential exposure may occur during the use of treated products such as 

paints and coatings, surface cleaners, floor cleaners, carpet cleaners, textiles and leather. 

Residential exposures were not assessed in the RED because it was believed at the time that 

the exposures would be very low due to dilution. While it is true that the use rates are fairly 

low, the toxicological endpoints are also fairly low and therefore it will be necessary to 

assess these exposures during registration review.

Aggregate and Cumulative Exposure and Risk

In examining aggregate exposure, EPA takes into account the available and reliable 

information concerning exposures to pesticide residues in food and drinking water, as well as 

non-occupational pesticide exposures. An aggregate risk assessment in the case of sodium 

pyrithione will likely be needed because of the use pattern which is likely to result in dietary, 

drinking water and residential exposures.

EPA does not have, at this time, available data to determine whether sodium pyrithione has a 

common mechanism of toxicity with other substances or how to include this pesticide in a 

cumulative risk assessment.

For the purposes of this Registration Review, EPA has assumed that sodium pyrithione does 

not have a common mechanism of toxicity with other substances when used as an 

antimicrobial as registered. 

Human Health Anticipated Data Needs

The Agency anticipates the need to require the following additional human health data for 

use in conducting the registration review of sodium pyrithione.

875.1100 -- Dermal outdoor exposure

875.1300 -- Inhalation outdoor exposure (HRSB costs not included)

875.1600 -- Application exposure data reporting and calculations

875.2300 -- Indoor surface residue dissipation

875.1700 -- Product use information

For more information, please refer to Sodium Omadine: Human Health Risk Assessment 

Scoping Document in Support of Registration Review, located in the docket.

Product Chemistry Anticipated Data Needs

The Agency does not anticipate the need to require additional product chemistry data for the 

registration review at this time.

For more information, please refer to Product Chemistry, Environmental Fate, and 

Ecological Effects Scoping Document in Support of Registration Review of Sodium Omadine, 

located in the docket.
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Incidents:

Ecological:

No Sodium Pyrithione ecological incidents have been reported in the Agency’s Ecological 

Incident Information System (EIIS).

Human Health:

No Sodium Pyrithione human poisoning incidents have been reported in the Agency’s OPP 

incident database.

Endangered Species

The Agency has not conducted a risk assessment that supports a complete endangered species 

determination for Sodium Pyrithione. The ecological risk assessment planned during registration 

review will allow the Agency to determine whether Sodium Pyrithione’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 Services (the Services), as appropriate.

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, 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), sodium pyrithione 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.
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Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. Sodium Pyrithione is not 

among the group of 58 pesticide active ingredients on the initial list to be screened under the 

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

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

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

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

Timeline

EPA has created the following estimated timeline for the completion of the Sodium Pyrithione

registration review:

Anticipated Schedule

Activities Estimated Month/Year

Phase 1: Opening the docket

Open Public Comment Period for Docket Completed

December 2011

Close Public Comment Period for Docket Completed

Phase 2: Case Development

Develop Final Work Plan (FWP) Completed 

June 2012

Issue DCI June 2013

Data Submission June 2015

Open Public Comment Period for Preliminary Risk Assessments December 2016

Close Public Comment Period for Preliminary Risk Assessments January 2017

Phase 3: Registration Review Decision

Open Public Comment Period for Proposed Reg. Review Decision June 2017

Close Public Comment Period for Proposed Reg. Review Decision August 2017

Final Decision and Begin Post-Decision Follow-up December 2017

Total (years) 6

Next Steps

A DCI will be developed regarding the data needs listed under the “Risk Assessments and 

Anticipated Data Needs” section of this document. The Agency expects to issue the DCI in June 

2013. Human health and environmental fate and ecological hazard assessments will be 

conducted for all uses. 
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Summary of Anticipated Data Requirements – Sodium Pyrithione

The table below summarizes anticipated data needs for the Sodium Pyrithione Case in this 

document (Final Work Plan), Product Chemistry, Environmental Fate, and Ecological Effects 

Scoping Document in Support of Registration Review of Sodium Pyrithione, and Sodium 

Pyrithione: Human Health Risk Assessment Scoping Document in Support of Registration 

Review.

Table 1. Summary of Anticipated Data Requirements – Sodium Pyrithione

Guideline

Number Anticipated Data Requirement Test Material

Estimated Timeframe 

(Measured in months from DCI 

Receipt)

875.110 Indoor Exposure, Dermal TGAI 24

875.1300 Indoor Exposure, Inhalation TGAI 24

875.1600 Data Reporting/Calculations TGAI 24

875.2300 Surface Residue Dissipation TGAI 24

875.1700 Product Use Information TGAI 24

835.2240 Photodegradation in water TGAI 12

850.6800 Activated Sludge Respiration Inhibition TGAI 12

835.3110 Ready Biodegradability2 TGAI 12

835.3220 Porous Pot Test2 TGAI 12

835.3280

Simulation Tests to Assess the 

Biodegradability of Chemicals Discharged to 

Wastewater2

TGAI 12

835.3240 Simulation Test – Aerobic Sewage Treatment: 

A. Activated Sludge Units2 TGAI 12

850.5400 Algal toxicity (Tier II) using freshwater green 

alga, Selenastrum capricornutum TGAI 12

_______________________________

2 The results of the Activated Sludge Respiration Inhibition Test (ASRI) will determine which of these four 

biodegradation tests will be required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the (i) 

Biodegradation in Activated Sludge Study or (ii) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge 

Units or (iii) the Porous Pot Test would be required. If the ASRI test EC50 is greater than 20 mg/L, then the 

registrant can choose to conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or 

b) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready 

Biodegradability study is conducted and passes, then no further testing is required. If, however, the antimicrobial 

fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or b) Simulation Test –

Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study is required.