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HHT Registration Review Team

Human Health & Environmental Effects

David Bays

Najm Shamim

Pat Jennings

Nate Mottl

Jenny Tao

Kristin Rury

Don Wilbur

Risk Management

Tina Pham

Rose Kyprianou

Elizabeth Watkins

Seiichi Murasaki

Office of General Counsel

Philip Ross
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TERMS, ABBREVIATIONS AND SYMBOLS

A.I. or a.i. active ingredient

ASRI activated sludge respiration inhibition

atm-m3/mole atmospheric pressure-cubic meter per mole

°C degrees Celsius

CAS Chemical Abstracts Service 

CFR Code of Federal Regulations 

COC concentration-of-concern

DCI data call-in

EC50 median (or 50 percent) effect concentration

ECOTOX ECOTOXicology

EDI estimated daily intake

EDSP Endocrine Disruptor Screening Program 

E-FAST Exposure and Fate Assessment Screening Tool

EP end-use product

EPI Suite Estimation Program Interface Suite

EPA Environmental Protection Agency

FDA Food and Drug Administration 

FFDCA Federal Food, Drug, and Cosmetic Act

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act

FQPA Food Quality Protection Act 

FWP Final Work Plan

g/mol grams per mole

GLN guideline number

H2S hydrogen sulfide

HHT hexahydro-1,3,5-tris (2-hydroxyethyl)-s-triazine

Koc organic carbon normalized soil-water partition coefficient

Kow octanol-water partition coefficient

LC50 median (or 50 percent) lethal concentration

LD50 median (or 50 percent) lethal dose

LOAEC lowest-observed-adverse-effect-concentration 

LOAEL lowest-observed-adverse-effect-level

Log Kow logarithm of the octanol-water partition coefficient

μg microgram

ml/g milliliter per gram

mg/kg milligram per kilogram

mg/kg/day milligram per kilogram per day 

mg/L milligram per liter

mm Hg millimeter of mercury

MOE margin of exposure 

MP manufacturing-use product

MRID Master Record Identification Number

MRL maximum residue limit 

N/A not applicable 

nm nanometers

NOAEC no-observed-adverse-effect-concentration

NOAEL no-observed-adverse-effect-level

OCSPP Office of Chemical Safety and Pollution Prevention

OECD Organization for Economic Co-operation and Development
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OPP Office of Pesticide Programs

PC Code Pesticide Chemical Code

pH power of hydrogen or power of the concentration of the hydrogen ion

pKa power of the acid dissociation constant or negative base-10 logarithm of the acid 

dissociation constant of a solution

ppb parts per billion 

ppm parts per million

PWP Preliminary Work Plan

QSAR quantitative structure-activity relationship

RED Reregistration Eligibility Decision

SAR structure activity relationship

SF safety factor

TGAI technical grade active ingredient

TMDL total maximum daily loads

UF uncertainty factor

UV/VIS ultraviolet/visible light absorption

WWTPs wastewater treatment plants
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Table of Contents

1 Introduction............................................................................................................................. 7

1.1 Statutory and Regulatory Authority ................................................................................. 7

1.2 Case Overview ................................................................................................................. 8

1.3 Chemical Identification and Properties............................................................................ 9

1.4 Use/Usage Description................................................................................................... 10

1.4.1 Registrations ........................................................................................................... 10

1.4.2 Summary of Registered Uses.................................................................................. 11

1.4.3 Summary of Risk Mitigation Measures from HHT RED ....................................... 11

1.4.4 Usage Information .................................................................................................. 12

1.5 Regulatory History ......................................................................................................... 12

1.5.1 Tolerance Information ............................................................................................ 12

1.6 Incidents......................................................................................................................... 12

1.6.1 Human Health ......................................................................................................... 12

1.6.2 Ecological ............................................................................................................... 13

2 Anticipated Data Needs........................................................................................................ 13

3 Human Health Risk Assessment........................................................................................... 17

3.1 Existing Toxicological Endpoints.................................................................................. 17

3.2 Dietary Exposure............................................................................................................ 18

3.2.1 Drinking Water ....................................................................................................... 18

3.3 Occupational and Residential Exposures....................................................................... 19

3.3.1 Occupational Handler Exposure ............................................................................. 19

3.3.2 Occupational Post-application Exposures............................................................... 19

3.3.3 Residential Handler................................................................................................. 20

3.3.4 Residential Post-Application Exposures................................................................. 20

3.4 Aggregate and Cumulative Exposure............................................................................. 20

3.4.1 Aggregate Exposures.............................................................................................. 20

3.4.2 Cumulative Exposures............................................................................................ 20

4 Environmental Risk Assessment .......................................................................................... 21

4.1 Environmental Fate Assessment .................................................................................... 21

4.1.1 Water Quality.......................................................................................................... 22

4.2 Conceptual Models for Environmental Exposure Pathways.......................................... 22

4.3 Ecological Effects Assessment....................................................................................... 22

4.3.1 Mechanism of Action.............................................................................................. 23

4.3.2 Measures of Effect (Ecotoxicology Endpoints)...................................................... 23

4.4 Exposure Analysis Plan.................................................................................................. 24

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates ............................................ 24

4.4.2 Screening Level Down-the-Drain Analysis............................................................ 25

4.5 Effects Analysis Plan ..................................................................................................... 25

5 Endocrine Disruptor Screening Program (EDSP) ................................................................ 25

6 Label Changes....................................................................................................................... 26

7 Guidance for Commenters.................................................................................................... 26

7.1 Preliminary Work Plan................................................................................................... 26

7.1.1 Trade Irritants.......................................................................................................... 26

7.1.2 Water Quality.......................................................................................................... 27

7.1.3 Environmental Justice............................................................................................. 27
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7.1.4 Structure Activity Relationships............................................................................. 27

7.1.5 Additional Information ........................................................................................... 28

8 Next Steps............................................................................................................................. 28

9 References............................................................................................................................. 29

Appendix A Toxicology Profile .............................................................................................. 30

Appendix B Environmental Fate ............................................................................................. 49

Appendix C Ecotoxicology Profile.......................................................................................... 51

Appendix D Screening Level Down-the-Drain Analysis........................................................ 57

Appendix E Product Chemistry............................................................................................... 58

List of Tables

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for Registration Review: 

HHT ................................................................................................................................................ 8

Table 2 – Anticipated Registration Review Schedule .................................................................... 9

Table 3 – Chemical Identification of HHT..................................................................................... 9

Table 4 – Physical-Chemical and Environmental Fate Properties for HHT................................. 10

Table 5 – Summary of HHT Registered Uses .............................................................................. 11

Table 6 – Risk Mitigation Measures Specified in the HHT RED................................................. 12

Table 7 – Studies Anticipated as Needed for the Registration Review of HHT........................... 14

Table 8 – Data Required by the May 12, 2010 Data Call-In for the HHT RED .......................... 16

Table 9 – Existing Toxicological Endpoints for HHT.................................................................. 17

Table 10 – Occupational Handler Exposure Scenarios for HHT.................................................. 19

Table 11 – Ecological Effects Endpoints Selected for Assessing Risks from HHT Use ............. 23
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1 Introduction

This document is the United States Environmental Protection Agency’s (USEPA, EPA or “the 

Agency”) Preliminary Work Plan (PWP) for hexahydro-1,3,5-tris (2-hydroxyethyl)-s-triazine,

also herein referred to as HHT. The PWP document explains what EPA's Office of Pesticide 

Programs (OPP) knows about HHT, 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 HHT’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 HHT and what types of new data or other 

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

The Agency encourages all interested stakeholders to review the PWP and to provide comments 

and additional information that will help the Agency’s decision-making process for this 

chemical.

The antimicrobial agent in HHT is formaldehyde (HCHO); therefore, this registration review

also addresses potential risks associated with formaldehyde exposure from HHT uses. Products 

containing formaldehyde as an active ingredient will be evaluated under registration review case 

0556. EPA’s formaldehyde RED is available in the formaldehyde public docket at 

http://www.regulations.gov in docket number EPA-HQ-OPP-2008-0121.

1.1 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 generally must be registered by the USEPA 

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 at 

http://www2.epa.gov/pesticide-reevaluation.

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 
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comment period, the Agency will develop and commit to a Final Work Plan (FWP) and 

anticipated schedule for the HHT case. 

1.2 Case Overview

The docket for HHT (case #3074) has been established at http://www.regulations.gov in docket 

number EPA-HQ-OPP-2014-0654. Documents associated with this registration review can be 

viewed at this docket. Tables 1 and 2 below summarize the issues relevant to this registration 

review case and the anticipated registration review schedule. 

Table 1 – Summary of Anticipated Risk Assessments and Data Needs for Registration 

Review: HHT

Risk Assessment 

Assessment 

Necessary to 

Support 

Registration 

Review

Date of 

Most Recent 

Assessment

Type of 

Assessment 

Required 

(New/Updated)

Data Anticipated as Needed

(See Table 7 for details)

Dietary (food) No

(See section 3.2)

6/30/2008 None None

Dietary (drinking water) Yes N/A New None (See section 3.2.1)

Occupational Handler Yes 6/30/2008 Updated Immunotoxicity 

Indoor Inhalation Exposure

Residential Handler No

(See section 3.3.3)

6/30/2008 None None

Residential Post 

Application - Incidental 

Oral and Dermal 

No

(See section 3.3.4)

6/30/2008 None None 

Residential Post 

Application - Inhalation 

No

(See section 3.3.4)

6/30/2008 None None 

Aggregate No N/A None None

Cumulative No

(See section 3.4.2)

N/A None None

Tolerance Review No

(See section 1.5.1)

N/A None None 

Ecological Yes 1/7/2008 Updated

Vascular plant growth

Algae growth

Fish early life stage

Aquatic invertebrate life cycle

Hydrolysis

Aerobic aquatic metabolism

Adsorption/desorption

Waste water treatment plant studies

N/A = Not applicable

* Table 1 is a summary of the anticipated risk assessments and data needs for Registration Review. For data called in through the 

post-Reregistration Eligibility Decision (RED) Data Call-In (DCI), see Table 8.
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Table 2 – Anticipated Registration Review Schedule

Anticipated Activity Target Date* Completion Date

Phase 1: Opening the Docket 

Open Docket and 60-Day Comment Period for Preliminary Work Plan 2014-12 2014-12

Close Public Comment Period 2015-02

Phase 2: Case Development 

Issue Final Work Plan 2015-06

Issue Data Call-In (DCI) 2016-06

Receive Data to be Considered in Risk Assessment 2018-06

Open 30-Day Public Comment Period for Preliminary Risk Assessment(s) 2019-12

Close Public Comment Period 2020-01

Phase 3: Registration Review Decision and Implementation 

Open 60-Day Public Comment Period for Proposed Decision 2020-06

Close Public Comment Period 2020-08

Issue Final Decision 2020-12

Begin Post-Decision Follow-up 2020

Total (years) 6

*The anticipated schedule will be revised as necessary (e.g., need arising under the Endocrine Disruptor Screening Program with 

respect to the active ingredients in this case).

1.3 Chemical Identification and Properties

Table 3 presents the active ingredient to be assessed in case 3074: HHT (PC Code 083301). 

Note: HHT is also a formaldehyde releaser. The remaining compound after the release of 

formaldehyde is 1,3,5-trimethyl triazine.

Table 3 – Chemical Identification of HHT

Chemical Name HHT

Chemical Classification Cyclic triazines

PC Code 083301

CAS Number 4719-04-4

Molecular Formula C9H21N3O3

Molecular Weight 

(grams/mole) 219.29 g/mol

Molecular Structure

HHT

Formaldehyde 

CH2O

1,3,5 trimethyl triazine:

The HHT product chemistry information relevant to risk assessment is summarized in Table 4, 

and the details of the product chemistry and environmental fate information are discussed in 

Appendix E and B, respectively. The Agency has no existing environmental fate data on the 
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degradate 1,3,5 trimethyl triazine; studies are anticipated to be required for the registration 

review risk assessment (see table 7 for a list of anticipated studies on this degradate).

Table 4 – Physical-Chemical and Environmental Fate Properties for HHT

Guideline No. Parameter HHT

Physical/Chemical Properties

830.7000 pH NA

830.7050 UV/Visible Absorption NA

830.7200 Melting point (

o C) 155 o C

830.7550 Octanol-water partition coefficient at 25 o C (Log Kow)

-2.3 (pH 5, 24 C),

-2.0 (pH 7, 24 C);

-1.3 (pH 9 24 C); 

 (MRID # 47284308)

830.7840 Solubility in water (g/L) 3 g/L (EPI Suite, version 4.11)

830.7950 Vapor pressure (mmHg)

11.2 mm Hg, at 20 C;

15.15 mm Hg at 25 C;

61.1 mm Hg at 50 C);

 (MRID # 47284307) 

Mobility

Organic Carbon Partitioning Coefficient Log Koc 10 L/kg (EPI Suite, version 4.11)

Persistence in Water (half-life)

Hydrolysis1at 25 oC: 

Half- life at pH 5: 3.2 days; 

pH 7: 50 days; 

pH 9: 302 days 

 (MRID# 43181001)

Hydrolysis at 37 o C

pH 4, half -life = 0 min; 

pH 11.35, no degradation;

 (MRID# 47353803)

Aerobic aquatic metabolism ( half -life in days) Data gap (See table 7)

Adsorption/ desorption study Data gap (See table 7)

Persistence in WWTP (% removed) Data gap (See table 7)

[Ready biodegradation,....]2 Data gap (See table 7)

1. A hydrolysis study conducted with metalworking fluids was also conducted and is discussed further in Section 

4.1. The hydrolysis in this study resulted in the loss of a significant portion of the material which limited the 

utility of the study. 

2. A published study (Voet et al, 1975) indicated primary biodegradation; however, this study did not follow the 

degradation past the first degradate.

1.4 Use/Usage Description

1.4.1 Registrations

There are 11 EPA-registered products that contain HHT as an active ingredient (a.i.) and used 

primarily as material preservative, bactericide and fungicide in coolants, and for oilfield uses.

The percent a.i. for end-use products ranges from 39.3 percent to 78.5 percent, and the 

formulations include soluble concentrate, ready-to-use solution, flowable concentrate, 

formulation intermediate, emulsifiable concentrate, and wettable powder. Three of these 

products contain other active ingredients such as sodium pyrithione or 1, 2-benzisothiazolin-3-
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one. There is one formulation intermediate product (EPA Registration Number 1839-59) that 

contains 78.5 percent hexahydro-1,3,5-tris (2-hydroxyethyl)-s-triazine.

1.4.2 Summary of Registered Uses

Table 5 presents a summary of the registered uses of HHT that will be assessed for registration 

review. HHT can be applied by the following application methods: liquid pour, liquid pump, 

solid pour, and solid place. Several uses, application methods and application rates are to be 

mitigated as per the RED (see Table 6). 

Table 5 – Summary of HHT Registered Uses

Use Application Method Application Rate*

Material Preservatives

Coatings, inks, dyes and slurries

Liquid Pour

1100 ppm

Liquid Pump

Adhesives, dispersions, and emulsions

Solid Pour

2358 ppm

Solid Place

Liquid Pour

1650 ppm

Liquid Pump

Hydrogen Sulfide Scavenger Systems Unknown 6.44 lb ai/lb H2S

Fuel Oils

Liquid Pour 1180 ppm

Liquid Pump 1180 ppm

Reagents Used in Medical Fluids

Liquid Pour 393 ppm

Liquid Pump 393 ppm

Metal working fluids

Liquid Pour 500 ppm

Liquid Pump 500 ppm

Industrial Processes and Water Systems

Coolants

Liquid Pump

1180 ppm

Liquid Pour

Oilfield Uses

Solid Pour 1200 ppm

Solid Place 1200 ppm

Liquid Pump 1200 ppm

Liquid Pour 1200 ppm

* Only maximum application rates are captured.

1.4.3 Summary of Risk Mitigation Measures from HHT RED

The Agency notes that there are existing labels not yet in compliance with these risk mitigation 

measures. The Agency is actively taking steps to bring these labels into compliance. During 

registration review, the Agency does not anticipate needing to assess those uses that were found 

to be ineligible for reregistration. Table 6 presents the mitigation measures outlined in the 2008 

RED and corrects a typographical error from parts per billion (ppb) to parts per million (ppm).
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Table 6 – Risk Mitigation Measures Specified in the HHT RED

Mitigation Measures for 

HHT Use Site Risk(s) of Concern Mitigation Measures

Paints, Stains, and Coatings 

Residential handler inhalation exposure 

to HHT in paint Delete/cancel use Occupational handler inhalation 

exposure to formaldehyde in paint 

Metal Working Fluids 

Occupational handler inhalation 

exposure to formaldehyde in metal 

working fluids 

Reduce maximum application 

rate from 1600 ppm to 500 ppm1

Institutional and Household 

Cleaning Products 

Residential handler inhalation exposure 

to formaldehyde in cleaners. Residential 

handler inhalation exposure to HHT in 

laundry detergent 

Delete/cancel use 

Oil Field Secondary 

Recovery 

Occupational handler dermal exposure to 

HHT in oil field secondary recovery uses 

Reduce maximum application 

rate from 0.16% active 

ingredient (ai) to 0.12% a.i. 

1. Error in the RED: Units should be parts per million (ppm), not ppb.

1.4.4 Usage Information

No usage information is available for HHT in the Kline Biocides Report for the period spanning 

2004 - 2013.

1.5 Regulatory History

The first product containing HHT as an active ingredient was registered in the United States in 

1972. The Agency completed a Reregistration Eligibility Decision (RED) for HHT in 2008. The 

post-RED DCI was issued on May 12, 2010. See Section 2 for a review of the status of the data 

required by the post-RED DCI.

1.5.1 Tolerance Information

EPA has not established tolerances in raw agricultural commodities or processed food and feed 

products for HHT under the Federal Food, Drug and Cosmetic Act (FFDCA) Section 408. There 

are also no tolerance exemptions for HHT under FFDCA Section 408. HHT has not been cleared 

as a food additive by the US Food and Drug Administration (US FDA) under FFDCA Section 

409. 

1.6 Incidents

1.6.1 Human Health 

In the case of HHT, there are three aggregate incidents listed in the IDS for the year 2008, when 

the RED was written, to the present, based on the search conducted on October 30, 2014. Two of 

these incidents are classified as cannot be rated (HE); no details were included. The remaining 

incident was classified as human minor (HD). Sore throat, watery eyes, respiratory irritation, and 
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burning of the lungs were experienced two weeks after occupational exposure to the aqueous 

product. 

1.6.2 Ecological

No HHT incidents have been reported in the Agency’s Ecological Incident Information System 

(EIIS) as of October 30, 2014.

2 Anticipated Data Needs

The Agency anticipates reviewing any data received in response to the post-RED DCI as well as 

data requested for this registration review prior to conducting the registration review risk 

assessments for HHT. Table 7 presents a summary of the data anticipated as being needed to 

support this registration review, and Table 8 presents a summary of the status of the post-RED 

DCI issued on May 12, 2010. 
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Table 7 – Studies Anticipated as Needed for the Registration Review of HHT

GLN Study Name Test Substance1

Time Frame 

(Measured in months 

from DCI Receipt)

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering 

Anticipated Data 

Requirement

Applicable 

Exposure Scenario

835.2120 Hydrolysis Parent and degradate: 

1,3,5-trimethyl triazine 12 All Industrial Water Processes, Material Preservative Use All

835.4300 Aerobic aquatic 

metabolism

Parent and the degradate: 

1,3,5-trimethyl-triazine 12 All Industrial Water Processes, Material Preservative Use All

835.1230 Adsorption/ desorption Parent and the degradate: 

1,3,5-trimethyl-triazine 12 All Industrial Water Processes, Material Preservative Use All

835.31102

835.32202

835.32402

835.32802

Ready biodegradability 

or one of three 

biodegradation in 

activated sludge 

simulation tests

Parent and the degradate: 

1,3,5-trimethyl triazine 12 All Industrial Water Processes, Material Preservative Use Down the drain

850.33003 Activated sludge, 

respiration inhibition test

Parent and the degradate: 

1,3,5-trimethyl triazine 12 All Industrial Water Processes, Material Preservative Use Down the drain

__________________________

1

Information on the degradate 1,3,5-trimethyl triazine which remains after the release of formaldehyde may potentially be available from information on other 

triazines. The registrants could propose triazine data and bridging information if appropriate in lieu of guideline studies on the degradate.

2 The results of the Activated Sludge, Respiration Inhibition Test (ASRI), GLN 850.3300, will determine which of the four biodegredation tests would be required. 

 If the ASRI test results in an EC50 of less than or equal to 20 mg/L, then either the (i) Simulation tests to assess the biodegradability of chemicals 

discharged in wastewater, GLN 835.3280, (ii) the Simulation Test – Aerobic Sewage Treatment -– A. Activated Sludge Units, GLN 835.3240, or (iii) the 

Porous Pot Test, GLN 835.3220 would be required.

 If the ASRI test results in an EC50 greater than 20 mg/L, then the registrant would be required to conduct either the (i) Ready Biodegradability, GLN 

835.3110, (ii) Simulation tests to assess the biodegradability of chemicals discharged in wastewater, (iii) the Simulation Test – Aerobic Sewage Treatment 

– A. Activated Sludge Units, or (iv) the Porous Pot Test. 

 If the Ready Biodegradability Study is conducted and passes, then no further testing would be required. If, however, the pesticide fails the Ready 

Biodegradability study, then the (i) Simulation tests to assess the biodegradability of chemicals discharged in wastewater, (ii) the Simulation Test –

Aerobic Sewage Treatment – A. Activated Sludge Units, or (iii) the Porous Pot Test would be required.

3 EPA published draft guidance under guideline 850.6800 and has since published final guidance for this study under guideline 

850.3300: http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0021. 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.
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GLN Study Name Test Substance1

Time Frame 

(Measured in months 

from DCI Receipt)

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering 

Anticipated Data 

Requirement

Applicable Exposure 

Scenario

850.1300 Aquatic invertebrate 

life cycle TGAI 12 Ecological Assessment Industrial Water Processes, Material Preservatives Down the drain

850.1400 Fish early life stage TGAI 12 Ecological Assessment Industrial Water Processes, 

Material Preservatives Down the drain

850.4400 Aquatic vascular plant 

growth TGAI 12 Ecological Assessment Industrial Water Processes, Material Preservatives Down the drain

850.45004 Aquatic algal growth TGAI 12 Ecological Assessment Industrial Water Processes, 

Material Preservatives Down the drain

850.45504 Algal Toxicity Tier II TGAI 12 Ecological Assessment Industrial Water Processes, 

Material Preservatives Down the drain

870.7800 Immunotoxicity TGAI 12 All All All

875.25005

Inhalation Exposure Degradate: formaldehyde 24 Occupational Postapplication

Manufacturing Settings of 

Material Preservatives

Post-application 

Exposure Bystanders

__________________________

4 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 Formaldehyde inhalation exposures are expected to occur to worker bystanders as a result of HHT material preservative applications in industrial settings. 

Currently, no data are available to assess these worker bystander exposures, and therefore, monitoring data are anticipated to be needed.
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Table 8 – Data Required by the May 12, 2010 Data Call-In for the HHT RED

GLN Study Name Test 

Substance

Risk Assessment(s) 

Data Will Support

Use Site(s) Triggering 

Anticipated Data 

Requirement

Applicable Exposure 

Scenario Status

870.1300 Acute inhalation toxicity TGAI, MP Occupational Handlers All Human Health Exposure Unsatisfied

870.3150 90-day oral toxicity in non-rodents TGAI Occupational Handlers; 

Drinking Water All Human Health Exposure Unsatisfied1

870.3465 90-day inhalation toxicity TGAI Occupational Handlers All Human Health Exposure Unsatisfied1

870.3700 Prenatal developmental toxicity 

study in non-rodent TGAI Occupational Handlers; Drinking Water All Human Health Exposure Unsatisfied1

870.3800 Reproduction and fertility effects TGAI Occupational Handlers; 

Drinking Water All Human Health Exposure Unsatisfied1

870.4100 Chronic toxicity TGAI Occupational Handler; 

Drinking Water All Human Health Exposure Unsatisfied1

870.4200 Carcinogenicity TGAI Occupational Handler; 

Drinking Water All Human Health Exposure Unsatisfied1

875.1100 Dermal exposure--outdoor EP Occupational Handler

Material Preservatives; 

Industrial Processes and 

Water Systems

Pour Liquid

Pour Solid Unsatisfied

875.1200 Dermal exposure--Indoor EP N/A N/A N/A Waived2

875.1300 Inhalation exposure--outdoor EP Occupational Handler

Material Preservatives; 

Industrial Processes and 

Water Systems

Pour Liquid

Pour Solid Unsatisfied

875.1400 Inhalation exposure--indoor EP N/A N/A N/A Waived2

875.1600 Application exposure monitoring 

data reporting EP N/A N/A N/A Waived3

875.1700 Product Use Information EP Occupational Handler

Material Preservatives; 

Industrial Processes and 

Water Systems

Pour Liquid

Pour Solid Unsatisfied

875.2700 Product Use Information EP Occupational Post-application; 

Occupational Bystander

Metalworking Fluids;

Oil Field

Occupational Post-application; 

Occupational Bystander Unsatisfied

875.2800 Description of human activity EP Occupational Post-application; 

Occupational Bystander

Metalworking Fluids;

Oil Field

Occupational Post-application; 

Occupational Bystander Unsatisfied

875.2900 Data reporting and calculations EP N/A N/A N/A Waived3

*N/A = not applicable

1. Registrants may submit a guideline hydrolysis study (anticipated to be called-in under registration review) to confirm the appropriate test substance for these toxicity studies.

2. Only outdoor exposure data is required.

3. The Agency will waive the data reporting studies (GLN 875.1600 and 875.2900) as the data requirement is now incorporated in the dermal or inhalation exposure study. 
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3 Human Health Risk Assessment

The Agency anticipates the need to conduct a human health risk assessment for HHT and its

degradate, formaldehyde, upon receipt of the additional data required under the post-RED DCI.

Additionally, the Agency anticipates the need to require additional data for currently registered 

uses under registration review. These additional studies include an immunotoxicity and an 

inhalation exposure study (as noted in Table 7).

The Agency is currently reevaluating the carcinogenic potential of formaldehyde and completing 

a new Integrated Risk Information System (IRIS) assessment and unit risk value for 

formaldehyde. The Agency plans to use this revised assessment, once the peer review process is 

completed, to evaluate the risk related to formaldehyde released as a result of the uses of HHT as

an antimicrobial pesticide. 

3.1 Existing Toxicological Endpoints

The Agency anticipates the need to revise the existing toxicological endpoints, shown in Table 9,

as part of this registration review. All available information, including existing toxicology 

studies and valid scientific literature, will be considered in establishing the toxicology endpoints 

to be used in the registration review risk assessment. Additional studies, as outlined in Table 7, 

are anticipated to be required, particularly for registered uses that may result in dietary exposure. 

A detailed description of the available toxicity studies is provided in Appendix A.

Table 9 – Existing Toxicological Endpoints for HHT

Exposure Scenario

Dose Used in Risk 

Assessment 

(mg/kg/day)

Target Margin of 

Exposure (MOE), 

Uncertainty Factor (UF), 

FQPA Safety Factor (SF)

Study and Toxicological Effects

Dietary Risk Assessment

Acute Dietary

(All populations)

NOAELmaternal = 500 MOE = 1,000 (10x 

interspecies, 10x 

intraspecies, 10x database 

uncertainty)

Developmental Toxicity – Rat 

(MRID 41161801) 

LOAELmaternal = 750 mg/kg/day, based on 

decreased body weight gain, ulcerations,

and scarring of the stomach mucosa

Acute RfD Acute RfD = 500 mg/kg/day ÷ 1000 = 0.5 mg/kg/day

Chronic Dietary

(All populations)

NOAEL = 50 UF = 100 (10x – Intra; 10x 

– Inter)

90-day Oral Study – Rat 

(MRID 41483001)

LOAEL = 100 mg/kg/day, based on 

lymphocytic infiltration in females and 

erosion of gastric mucosa and prominence 

of the limiting ridge of the stomach in males

Chronic RfD Chronic RfD = 50 mg/kg/day ÷ 100 = 0.5 mg/kg/day

Occupational/Residential (Non-Dietary) Risk Assessment
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Exposure Scenario

Dose Used in Risk 

Assessment 

(mg/kg/day)

Target Margin of 

Exposure (MOE), 

Uncertainty Factor (UF), 

FQPA Safety Factor (SF)

Study and Toxicological Effects

Incidental Oral 

Short-Term 

(1-30 days)

NOAELmaternal = 500 MOE = 1,000 (10x 

interspecies, 10x 

intraspecies, 10x database 

uncertainty)

Developmental Toxicity – Rat 

(MRID 41161801) 

LOAELmaternal = 750 mg/kg/day, based on 

decreased body weight gain, ulcerations,

and scarring of the stomach mucosa

Incidental Oral

Intermediate-Term 

(30 days- 6 months)

NOAEL = 50 UF = 100 (10x – Intra; 10x 

– Inter)

90-day Oral Study – Rat 

(MRID 41483001)

LOAEL = 100 mg/kg/day, based on 

lymphocytic infiltration in females and 

erosion of gastric mucosa and prominence 

of the limiting ridge of the stomach in males

Dermal Absorption

Factor

Not required as a dermal toxicity study has been used for the dermal endpoint.

Dermal 

Short-Term

(1-30 days)

No risk assessment necessary because no adverse systemic effects observed in a 21-day dermal 

toxicity study up to 1,000 mg/kg/day. 

Dermal

Intermediate-term 

(30 days-6 months)

and long-term

(>6 months)

NOAELsystemic = 250 MOE = 1,000 (10x 

interspecies, 10x 

intraspecies, 10x database 

uncertainty)

90-day dermal Study – Rat 

(MRID 41483002)

Systemic NOAEL was found to be greater 

than 250 mg/kg/day (the HDT); systemic 

LOAEL was not established.

Inhalation

(all durations)

NOAEL = 50 MOE = 1000 

(10x interspecies, 10x 

intraspecies, 10x database 

uncertainty)

90-day Oral Study – Rat 

(MRID 41483001)

LOAEL = 100 mg/kg/day, based on 

lymphocytic infiltration in females and 

erosion of gastric mucosa and prominence 

of the limiting ridge of the stomach in males

3.2 Dietary Exposure

A dietary food exposure assessment is not required for HHT at this time. The registered uses are 

not expected to result in direct or indirect dietary (food) exposure. The Agency anticipates the 

need to determine the potential for discharged residues of HHT to result in human dietary 

exposure via drinking water, which may trigger a dietary (drinking water only) assessment

during Registration Review. 

3.2.1 Drinking Water

A drinking water assessment has not been conducted for HHT and its primary triazine degradate, 

in the past. However, the Agency cannot rule out the potential for HHT to enter drinking water. 

There are uncertainties with respect to the residues of concern in drinking water, the magnitude 

of these potential residues concern, their mammalian toxicities, how persistent they will be, and 

if they are likely to pass through a wastewater treatment plant (WWTP) is unknown. Therefore, 

the Agency anticipates needing certain environmental fate data listed in Section 4 of this PWP. 
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These data will be useful to determine the extent residues of HHT and its primary triazine 

degradate pass through a WWTP. The Agency anticipates using these data and/or other sources 

of information during the risk assessment stage of registration review to determine the potential 

for discharged residues of HHT to result in human dietary exposure via drinking water, which 

may trigger a drinking water assessment.

3.3 Occupational and Residential Exposures

The Agency anticipates the need to update the occupational and residential exposure (ORE) 

assessment done for the 2008 RED during registration review. The assessment from the RED 

will need to be revised to account for scenarios that were identified after the RED and to utilize 

the exposure data anticipated to be received from the post-RED and registration review data callins.

3.3.1 Occupational Handler Exposure

EPA anticipates the need to revise the occupational handler assessment conducted in support of 

the 2008 RED (D346240). Occupational handler dermal and inhalation exposures to HHT were 

assessed in the RED for the following applications: liquid pour, liquid pump, solid pour, and 

solid place. The Agency expects to conduct new assessments for liquid pour and solid pour 

scenarios in registration review upon receipt of the anticipated exposure data expected from the 

post-RED DCI.

The Agency also anticipates that it will need to reassess the exposure of metalworking fluid and 

the oil field secondary recovery uses in registration review. The scenario may need a new risk 

assessment if there will be a change in the toxicological endpoint or if new exposure data are

submitted in registration review. Table 10 lists the scenarios that the Agency anticipates that will 

be need to be assessed in registration review.

Table 10 – Occupational Handler Exposure Scenarios for HHT

Scenario Exposure 

Route(s) Duration

Occupational Exposures

Liquid Pour for Material Preservatives and Industrial Processes and 

Water Systems

Dermal 

Inhalation 

Short and Intermediate 

Term 

Solid Pour for Material Preservatives and Industrial Processes and 

Water Systems

Dermal 

Inhalation 

Short and Intermediate 

Term 

Occupational Handler Inhalation Exposure to Formaldehyde in Metal 

Working Fluids and Oil Fields Inhalation Short and Intermediate Term

3.3.2 Occupational Post-application Exposures

Metalworking Exposure

The RED assessed the dermal and inhalation exposure when a worker handles treated 

metalworking fluids with HHT and the HHT degradate formaldehyde. According to the RED, 

the dermal MOE value for HHT is above the target MOE of 1,000 for intermediate- and long-
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term exposures (MOE = 3,100). The inhalation MOE values for ST/IT/LT exposures to HHT are 

above the target MOE of 100 (ST/IT/LT MOE = 44,000). 

In the RED, the Agency assessed inhalation risks from HHT by using an inhalation monitoring 

study which measured formaldehyde levels in a metalworking facility. For the monitoring study 

(D346240), there were two studies presented: Linnainmaa, 2003 and Cohen, 1993 measured 

formaldehyde exposures from production operations. The majority of the concentrations 

exceeded the 100 ppb level of concern. As a result, the Agency specified reduced maximum 

application rates for HHT metalworking in the RED from concentrations of 1600 ppm to 500 

ppm since some samples were above the OSHA PEL ceiling value. During registration review, 

the need to revise the existing inhalation assessment for formaldehyde will be revisited once data 

have been received.

Industrial Bystander Inhalation Exposure

Formaldehyde inhalation exposures are expected to occur to bystanders as a result of HHT 

material preservative applications in oil fields. Currently, no data are available to assess the 

bystander exposures and therefore, monitoring data are expected to be needed. The data were not 

called in the post-RED DCI, but the Agency anticipates the need for an inhalation chamber test 

to fulfill the post-application exposure data (Series 875.2500) in registration review. 

3.3.3 Residential Handler

All of the HHT residential handler uses such as treated paints, cleaners and detergents were 

already assessed in the RED, and the Agency determined these uses were ineligible for 

reregistration as a result of handler risk concerns. There are no other residential uses for HHT.

3.3.4 Residential Post-Application Exposures

All of the HHT residential post-application uses such as treated paints, cleaners and detergents 

were already assessed in the RED, and the Agency determined these uses were ineligible for 

reregistration as a result of risk concerns identified.

3.4 Aggregate and Cumulative Exposure

3.4.1 Aggregate Exposures 

The Agency does not anticipate conducting an aggregate assessment as only drinking water 

exposures will need to be considered. Residential and dietary uses (such as paint, cleaners and 

detergents) were identified in the RED as risks of concern and found ineligible for reregistration.

3.4.2 Cumulative Exposures 

With respect to cumulative exposure, unlike other pesticides for which EPA has followed a

cumulative risk approach based on a common mechanism of toxicity, EPA has not made a 

common mechanism of toxicity finding as to HHT and any other substances and HHT does not 

appear to produce a toxic metabolite produced by other substances. Therefore, for the purposes 

of this registration review, EPA has not assumed that HHT has a common mechanism of toxicity 
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with other substances. For information regarding EPA’s efforts to determine which chemicals 

have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, 

see http://www.epa.gov/pesticides/cumulative/. 

4 Environmental Risk Assessment

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

species determination for HHT. The ecological risk assessment planned during registration 

review will allow the Agency to determine potential acute and chronic risks to aquatic organisms 

exposed to HHT transported from treatment sites into the aquatic environment. The risk 

assessment also will allow the Agency to determine whether each use of the HHT 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.

4.1 Environmental Fate Assessment

The Agency has received several studies regarding the hydrolysis of HHT including hydrolysis 

in buffered waters and metal working fluids, at different concentrations of HHT and different 

temperature regimes. HHT hydrolyzes rapidly at acidic pHs, shows slow hydrolysis at more 

neutral pHs and is stable at basic pHs. In one study, at 25oC, HHT hydrolyzed within seconds at 

lower pHs (1 to 4), with a half-life of 3.2 days at pH 5, and with a half-life of approximately 50 

days at pH 7. The rate of the hydrolysis reaction is sensitive to temperature with more rapid 

breakdown seen at 37o C than at 25o C. Hydrolysis at all pHs results in the release of 

formaldehyde. After the release of formaldehyde from HHT, the remaining compound is 1,3,5-

trimethyl triazine. A second hydrolysis study designed to estimate the rate of formaldehyde 

release in aqueous metalworking fluid was conducted at 25o and 35o C with HHT concentrations 

of 4, 5 and 6%. Hydrolysis was observed, but approximately 30% of the material was 

unaccounted. Since the study did not provide any rationale for this loss (MRID# 48741001), it 

provides supplemental information on hydrolysis. The Agency anticipates requiring hydrolysis 

information on HHT which follows the formation and decline of the triazine degradate.

HHT is a volatile substance with a measured vapor pressure of 15.15 mm Hg at 25oC and 

volatility is possibly due to slow release of formaldehyde from HHT. HHT is also highly water 

soluble, and as water vapor volatilizes from surface water, it is likely to volatilize along with the 

water vapor. However, since the estimated half-life in air is about 16 minutes, HHT is not 

expected to persist in air.

Although a published literature study (Voets, et al, 1975), concluded that HHT is a ready 

biodegradable pesticide, the study only measured the primary degradation of HHT and did not 

identify or follow biodegradation of the resulting compounds. In order to characterize the 

potential for biodegradation, additional information on the formation and decline of degradates is 

anticipated to be needed.
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The estimated Koc of HHT is 10 L/kg which indicates it is mobile in soils. It has a low Log Kow of

-2.3 and is therefore is not expected to bioaccumulate in the food chain.

The Agency has a fairly complete environmental fate database for formaldehyde, but at this time, 

has no environmental fate and transport data on the degradate 1,3,5-trimethyl triazine and limited 

information on HHT. It has no information on the down-the-drain data (ASRI, ASSI, 

Biodegradability) of HHT and 1,3,5-trimethyl triazine. These studies are anticipated to be 

required during registration review.

4.1.1 Water Quality

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

section 303(d) of the Clean Water Act.

1

In addition, no Total Maximum Daily Loads (TMDL) 

have been developed for HHT.

2 More information on impaired water bodies and TMDLs can be 

found at EPA’s website.

3

4.2 Conceptual Models for Environmental Exposure Pathways

Based on the summary of registered uses of HHT presented in Table 5, physical/chemical 

properties and environmental fate data presented in Table 4 and Appendix B, the Agency has 

determined that some exposure of aquatic organisms to HHT and its degradates can potentially 

occur from releases of HHT and/or its degradates to surface water from industrial uses in metal 

working cutting fluids, and oil field drilling muds/workover fluids/completion fluids; and inservice use of in-can preservation of adhesives, chain lubricants, aqueous mineral slurries, and 

in-service use of caulks, spackling, grout, adhesives, and foams. 

The Agency has created conceptual models for potential routes of environmental exposure which 

are included in “Conceptual Models for Environmental Exposure Pathways of Antimicrobial 

Pesticides” (EPA-HQ-OPP-2014-0638-0002), found in the docket at www.regulations.gov, EPAHQ-OPP-2014-0638. For industrial use of metal working cutting fluids, refer to slide 18. For 

industrial use of oil field drilling muds/workover fluids/completion fluids, refer to slides 19 and 

20. For in-service use of in-can preservation of adhesives, chain lubricants, aqueous mineral 

slurries, paints, stains, and coatings, refer to slides 24 and 25. For in-service use of caulks, 

spackling, grout, adhesives, and foams, refer to slide 17. All relevant pathways of exposure will 

be considered when the Agency performs a risk assessment for HHT and its degradates.

4.3 Ecological Effects Assessment

A hazard assessment was conducted for all uses of HHT in 2008 (EPA, 2008). The hazard 

assessment was used to determine current labeling requirements for precautionary statements and 

to determine hazard endpoints for ecological organisms potentially exposed in the event of a spill 

or other unintended environmental releases. At that time, no ecological risk assessment was 

required for the registered uses. This was based on the use patterns, which indicated that release 

 

1 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

2http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES

3 http://www.epa.gov/owow/tmdl/
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and exposure levels were expected to be low when products were applied according to label 

directions and use precautions. The ecological risk assessment planned during registration review 

will allow the Agency to determine potential acute and chronic risks to aquatic organisms 

exposed to HHT transported from antimicrobial use sites into the aquatic environment. Since 

HHT is a formaldehyde releaser, the Agency has reviewed the eco-toxicity data for 

formaldehyde (EPA, 2008) and has compared the parent compound’s toxicity to that of 

formaldehyde. The toxicity patterns of the two compounds is similar, ranging from practically 

nontoxic to moderately toxic. Since formaldehyde data has been assessed in the RED and does 

not contribute new information to the HHT risk assessment, these data will not be included in 

this review. Therefore, the risk assessment will be based on the HHT toxicity data.

4.3.1 Mechanism of Action

HHT releases formaldehyde. The hydrolysis of formaldehyde-condensates at the cell boundary

(wall) effectively denatures this peptidoglycan structure and, thus, leads to cellular death.

4.3.2 Measures of Effect (Ecotoxicology Endpoints)

Ecological effects data are used as measures of direct and indirect effects to aquatic and 

terrestrial organisms. Acute and chronic toxicity data from registrant-submitted studies 

conducted in accordance with the 850 OCSSP Harmonized Test Guidelines will be used to 

evaluate the potential direct and indirect effects of HHT to animals and plants. Additionally, as 

described below, relevant data from the EPA’s Office of Water and from the open literature also 

may be used to evaluate potential direct and indirect effects. 

All available ecotoxicity endpoints from studies submitted by registrants are tabulated and 

referenced in the Ecological Effects Profile (Appendix C). OPP uses the most sensitive of these 

endpoints for assessing acute and chronic risks to each aquatic receptor group. The avian toxicity 

endpoint is used to determine the need for precautionary labeling for hazards to wildlife. The 

endpoints selected for the assessment for HHT from the data submitted to the Agency are 

provided in Table 11. Data gaps exist for chronic freshwater fish, chronic freshwater 

invertebrates, algae, and aquatic vascular plants, and these data are anticipated to be required.

Table 11 – Ecological Effects Endpoints Selected for Assessing Risks from HHT Use

Receptor Group Surrogate Species Risk 

Scenario Toxicity Endpoint Reference

Freshwater fish

Bluegill Sunfish Acute 96-h LC50 = 39 mg/L MRID# 248883

Rainbow Trout Acute 96-h LC50 = 41.7 mg/L MRID# 247712

Freshwater fish Bluegill Sunfish Chronic Data gap2--

Freshwater 

invertebrates Daphnia magna Acute 48-h EC50 = 26.1 mg/L MRID# 43175401

Chronic Data gap2--

Freshwater benthic 

invertebrates Freshwater midge Subchronic/Chronic Not required4

--

Estuarine/marine fish Sheepshead minnow Acute 96-h LC50 = >118 mg/L MRID# 43143102

Chronic Not required3--

Estuarine/marine 

invertebrates

Mollusk Acute 48-hr EC50 = 2.3 mg/L MRID# 43175402

Shrimp Acute 96-hr LC50 = 12 mg/L MRID# 43143103
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1 Not required for this use pattern based on a lack of exposure to terrestrial organisms.

2 Required for this use pattern. 

3 There are no data available, but acute to chronic ratios using freshwater acute and chronic data and estuarine acute 

data can be used to estimate chronic toxicity to estuarine/marine organisms.

4Not required for this use pattern based on its mobility in the soil (Koc = 10 L/kg). HHT is not expected to 

bioaccumulate in the food chain (Log Kow = -2.3).

4.4 Exposure Analysis Plan

4.4.1 Aquatic and Terrestrial Wildlife Exposure Estimates

To perform an analysis of potential risks from exposure of aquatic animals and plants to HHT 

and/or its degradates as a result of industrial uses of HHT, the Agency plans to use the General 

Population and Ecological Exposure from Industrial Releases module of E-FAST (Exposure and 

Fate Assessment Screening Tool). The input data required to run this E-FAST module include: 

(1) percent removal of antimicrobial during wastewater treatment; (2) environmental releases of 

antimicrobial to surface water in kg/site/day; (3) annual number of days of release to surface 

water; (4) Standard Industrial Classification (SIC) code(s) to represent the industrial uses being 

assessed; and (5) concentrations of concern (COCs) for aquatic animals and plants.

To perform an analysis of potential risks from exposure of aquatic animals and plants to HHT 

and/or its degradates from in-service uses, the Agency plans to use the Down-the-Drain module 

of E-FAST. The inputs required to run this module include percent removal of antimicrobial 

and/or its degradates during wastewater treatment, wastewater treatment plant influent volume, 

and COCs for aquatic animals and plants.

For both of these approaches, the number of days of exceedance of Concentrations of Concern 

(COCs) for HHT and/or its degradates will be used to determine the magnitude of exposure to 

aquatic organisms. The method used to estimate environmental releases of the antimicrobial 

pesticide and/or its degradates to surface water will be based on the specific end-use being 

Chronic Not required3--

Estuarine/marine 

benthic invertebrates Marine amphipod Subchronic/Chronic Not required4

--

Algae Green alga Nonlisted Data gap2--

Aquatic vascular plants Duckweed Nonlisted Data gap2--

Seedling Emergence Rice Nonlisted Not required1--

Vegetative vigor Rice Nonlisted Not required1--

Birds

Northern bobwhite 

quail Acute LD50 = 83.8 mg/kg MRID# 43154301

Mallard duck Subacute 

dietary

LC50 >5000 mg/kg MRID# 240113101

Chronic Not required1 --

Mammals Acute LD50 = 1250 mg/kg (males)

LD50 = 763 mg/kg (females) MRID# 41675206

Chronic Not required1--

Nontarget insects Honey bee Acute Not required1--
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evaluated. Values for ecotoxicity endpoints will be used to develop COCs used in these E-FAST 

modules.

4.4.2 Screening Level Down-the-Drain Analysis

As stated in Appendix D, a screening-level Down-the-Drain analysis of HHT was not performed 

since such an analysis is appropriate only for uses of antimicrobial pesticides that would be 

released solely to domestic wastewater treatment facilities. Uses of HHT include industrial uses 

that would be expected to have the potential to release HHT and/or its degradates to industrial 

wastewater treatment facilities and in-service uses that would be expected to have the potential to 

release HHT and/or its degradates to domestic wastewater treatment facilities. Since HHT has 

the potential to be released to both domestic and industrial wastewater treatment facilities, results 

from a screening-level down-the-drain analysis would provide incomplete information on the 

potential for risks to aquatic organisms from exposure to HHT and/or its degradates.

4.5 Effects Analysis Plan

Additional open literature studies will be identified through EPA’s ECOTOXicology (ECOTOX) 

database. The ECOTOX database will be searched during the risk assessment phase of HHT and 

the data reviewed following the Agency’s policy for reviewing public literature for use in

assessing risks from pesticides.

4 Those ecotoxicity values found in the public literature to be 

more sensitive than those currently in Table 11 and/or which satisfy an existing data gap(s) will 

be used during the risk assessment phase of HHT to update Table 11. ECOTOX was created and 

is maintained by the USEPA, Office of Research and Development, and the National Health and 

Environmental Effects Research Laboratory's Mid-Continent Ecology Division.

5 Endocrine Disruptor Screening Program (EDSP)

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 HHT, 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), HHT 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 

 

4http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/endangered_species_reregistration_wor

kgroup/esa_evaluation_open_literature.htm
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may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

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

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

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals 

identified for EDSP screening was published on June 14, 20135and 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 our 

website.6

6 Label Changes

As noted in section 1.4.3, the Agency is taking steps to bring outstanding HHT labels into 

compliance with risk mitigation measures from the HHT RED. Application rates should be 

lowered for certain HHT uses, including for oil field and metalworking fluids uses. In addition, 

all paints, stains, and coatings uses, and institutional and household cleaning product uses need 

to be removed to address RED mitigation. In addition, the Agency invites comment on any label 

amendments that could be considered to eliminate the anticipated need for EPA to require certain 

data, reduce the possibility that EPA’s planned risk assessments overestimate risk due to reliance 

on conservative assumptions, and/or improve label clarity.

7 Guidance for Commenters

7.1 Preliminary Work Plan

The public is invited to comment on EPA’s PWP and rationale. The Agency will carefully 

consider all comments as well as any additional information or data provided in a timely manner 

prior to issuing a final work plan for the HHT registration review case. 

7.1.1 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

 

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

chemicals.

6 http://www.epa.gov/endo/
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will work to harmonize tolerances and international maximum residue limits (MRLs) and may 

modify tolerance levels to do so, when possible. 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.

7.1.2 Water Quality

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 Process7in order to ensure they 

can be used quantitatively or qualitatively in pesticide risk assessments.

7.1.3 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 HHT 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.

7.1.4 Structure Activity Relationships 

EPA must rely upon information of appropriate quality and reliability for each decision made by 

the Agency. In the OPP, the evaluation process for a pesticide chemical traditionally begins with 

the applicant’s submission of a set of studies conducted with the specific pesticide chemical of 

interest. The use of the results of such testing (measured data) is a logical, scientifically rigorous 

process that identifies the physical, chemical, and environmental fate properties of the pesticide, 

as well as the dose and endpoints at which an adverse effect can occur in various animal species. 

Today, there is significant interest in alternative techniques, i.e., techniques other than data 

generation that could significantly inform the Agency’s decision-making process. Recently, OPP 

has made increasing use of structure activity relationship (SAR) as part of its regulatory 

decision-making process. In the SAR process, a chemical's molecular structure is compared to 

that of other chemicals for which data are available. These structural similarities are then used to 

make predictive judgments about a chemical’s physical, chemical, and biological properties. 

Thus, the chemical’s physical, chemical, and biological properties are a function of (or directly 

related to) the chemical’s molecular structure. Quantitative SAR is referred to as QSAR. To 

develop a QSAR, a selected set of measured data on a single physical, chemical, or biological 

property is used to derive a model (an equation) to predict the value of that property. 

 

7 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
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If stakeholders believe that submission of predicted data can fulfill one of the data needs for the 

HHT case, then the Agency invites submission of this information. The submitter would be 

expected to supply a rationale describing the utility of the information and provide 

documentation on the scientific validity of the information. The determination that the predicted

data fulfills the data requirement would be at the sole discretion of the Agency. Pre-submission 

consultation with the Agency is encouraged. 

7.1.5 Additional Information 

Stakeholders are also specifically asked to provide available information and data that will assist 

the Agency in refining its risk assessments, including any species-specific ecological effects 

determinations. The Agency is interested in receiving the following information: 

1. Confirmation on the following label information: 

A. Sites of application 

B. Formulations 

C. Application methods and equipment 

D. Maximum application rates 

E. Frequency of application, application intervals and maximum number of 

applications 

F. Geographic limitations on use 

2. Use or potential use distribution 

3. Use history 

4. Usage/use information for non-agricultural uses (e.g., materials preservation) 

5. Typical application interval 

6. State or local use restrictions 

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

mammalian mortalities) not already reported to the Agency

8. Monitoring data 

8 Next Steps

After the 60-day comment period closes in February 2015, the Agency will review and respond 

to any comments received in a timely manner, and then issue a Final Work Plan for the HHT

case.
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9 References

Holtzman, G.H., and Rossmoore, H.W. 1977. Evaluation of Action of a Formaldehyde 

Condensate Germicide. Dev Ind Microbiol 18:753-758. 

Linnainmaa, 2003. “Control of Worker’s Exposure to Airborne Endotoxins During Use of 

Metalworking Fluids,” Markuu Linnainmaa, Hannu Kivirata, Juha Laitinen and Sirpa 

Laitinen, Kuopio Regional Institute of Occupational Health and National Public Health 

Institute Department of Environmental Health, Kupio, Finland, Published in the AIHA 

Journal 64:496-5000, July/August 2003.

NIOSH 2003. NIOSH Method 2016 Issue 2: Formaldehyde, NIOSH Manual of Analytical 

Methods (NMAM), Fourth Edition, NIOSH, March 15, 2003.

U.S. EPA, 1999. Compendium of Methods for the Determination of Toxic Organic Compounds 

in Ambient Air, Second Edition, Compendium Method TO-11A, Determination of 

Formaldehyde in Ambient Air Using Adsorbent Cartridge Followed by High 

Performance Liquid Chromatography (HPLC, EPA/625R-96/010b, EPA ORD, January 

1999.

U.S. EPA, 2002. ECOTOX User Guide: ECOTOXicology Database System. Version 3.0. 

Available: http://www.epa.gov/ecotox/

U.S. EPA, 2008. Ecological Hazard and Environmental Risk Assessment Chapter: 

Formaldehyde, Paraformaldehyde. January 29, 2008. 

U.S. EPA, 2008. Reregistration Eligibility Decision (RED) for Grotan (HHT). June, 27, 2008.

Voets, JP, Pipyn, P, Van Lanker, P, and Verstraete, W: 1975: Degradation of Microbiocides 

under Different Environmental Conditions, J. Applied Bact.: 40:67-72
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Appendix A Toxicology Profile

Acute Toxicity for Product Labeling

As listed in Table A1, HHT was found to be low toxic for both acute oral and dermal toxicity 

(Toxicity Category III for both). An acute inhalation toxicity study is not available in the 

Agency’s hazard database and is required. This study was identified as a data gap in the RED. 

HHT was shown to be corrosive to the eyes (Toxicity Category I) but mildly irritating to skin

(Toxicity Category IV). HHT was shown not to be a dermal sensitizer.

Table A1. Acute Toxicity Studies for HHT

Guideline No./ Study Type MRID No. Results Toxicity 

Category

870.1100

Acute oral toxicity – Rat

(Purity 79.4%)

41675206 LD50 = 1250 mg/kg (males);

LD50 = 763 mg/kg (females) III

870.1100

Acute oral toxicity – Mouse

(Purity 78.5%)

00155959 LD50 = 1.30 (1.14 – 1.48) ml/kg III

870.1200

Acute Dermal Toxicity – Rabbit

(Purity 79.96%)

00155984 LD50 > 2000 mg/kg III

870.1300

Acute Inhalation Toxicity – Rat N/A N/A N/A

870.2400

Primary Eye Irritation – Rabbit

(Purity 79.96%)

00155985 Corrosive I

870.2500

Primary Dermal Irritation – Rabbit

(Purity 79.96%)

00155986 Mild irritant IV

870.2600

Dermal Sensitization – Guinea Pigs

(Purity 79.96%)

00155987 Not a sensitizer N/A

N/A=Not available 

Subchronic Toxicity 

Adequacy of Database for Subchronic Toxicity: The database for subchronic toxicity is 

considered incomplete. There are several studies in the Agency’s hazard database to address 

subchronic oral toxicity, including a 90-day oral (gavage) toxicity study (MRID 41483001), a 

90-day oral (drinking water) toxicity study (MRID 47300901), a 21-day (MRID 00155989) 

dermal study, and two 90-day dermal toxicity studies (MRIDs 41483002 & 41858301); all the 

studies are in the rat. A brief summary of each of the studies is provided below. A subchronic 

oral toxicity in non-rodent species and a route-specific subchronic inhalation toxicity study in 
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rodents are anticipated to be required for registration review risk assessment, based on the 

currently registered uses for HHT and its high volatility; these studies were identified as data 

gaps in the RED and are part of the data required by the post-RED DCI issued on May 12, 2010. 

870.3100 90-Day (13-Week) Oral Toxicity – Rat

(1) In a subchronic oral toxicity study (MRID 41483001), groups of Crl:CD(SD)BR rats 

(10/sex/group) received the test material HHT (78.5% a.i.) via gavage at doses of 0, 10, 50, 100, 

or 250 mg/kg/day, 5 days/week for 13 weeks. 

Mortalities were reported during the study period. With the exception of one female from the 

high dose group, the decedents had gross changes in the lung and/or thoracic cavity. The lungs in 

these animals did not collapse upon opening the thoracic cavity and adhesions or fluid was 

present in the area. Inflammatory changes and vascular congestions were present in the thoracic 

viscera. In addition to the thoracic lesions, all decedents from the high dose group showed a 

white discoloration and prominence of the limiting ridge of the stomach.

There were significant differences in the body weight gain and food consumption between 

treated and control rats. Absolute adrenal weights were increased for females in the high-dose 

group, although it was not statistically significant; an increase in splenic weight was also 

observed in all treated males. The sponsor attributes this difference to unusually low weights in 

control animals.

Grossly, a white discoloration and/or prominence of the limiting ridge of the stomach were 

present in all high-dose males and in the remaining high dose females which survived the 

duration of the study as well as in some of the animals in the second high dose groups. This gross 

finding was correlated with the treatment-related microscopic lesions in the stomach, including 

erosion of the glandular mucosa of the stomach, epithelial hyperplasia, and lymphocytic 

infiltration. Microscopic lesion in the liver was also observed including increased incidence of 

hepatocyte vacuolation in high dose males.

A statistically significant reduction in hematocrit was found in all treated males. Additionally, 

males in second high-dose group demonstrated a statistically-significant decrease in hemoglobin 

concentration. Although these findings were statistically significant, they were within the 

expected laboratory range.

Significant differences in blood chemistry values included reduced bilirubin in all treated groups, 

reduced total protein in both sexes of rats in high-dose group, and a statistically significant 

increase in sodium concentration for all treated males and for females in all treated groups except 

for the lowest dose group. The bilirubin and total protein values were within the normal range 

and were not considered to be biologically significant. 

A high frequency of peribronchiolar lymphoid hyperplasia was reported for all groups. The 

incidence of this finding ranged from 70 to 100 percent on both sexes. While this finding is not 

believed to be treatment-related, the significance of this finding was not addressed in the study 

report.
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Based on the results of this study, the systemic NOAEL is 50 mg/kg/day, and the systemic 

LOAEL is 100 mg/kg/day, based on gastric lesions (erosion of the mucosa and lymphocytic 

infiltration) in males and females.

This study is classified as Minimum. 

(2) In a 90-day oral toxicity study (MRID 47300901), Hexahydro-1,3,5-tris-(2-hydroxyethyl)-Striazine (79% a.i., Batch # 1157) was administered to 10 Wistar rats/sex/dose in water at dose 

levels of 0, 200, 1000, or 5000 ppm (equivalent to 0, 14.1, 64.1, or 285.2 mg/kg bw/day for 

males and 0, 21.2, 91.0, or 338.6 mg/kg bw/day for females).

High-dose animals showed reduced food and water consumption, reduced body weight (males 

only), reduced food efficiency, increased blood urea concentrations, and increased urine specific 

gravity as compared to the control group. Decreased water consumption was also observed in 

mid-dose (1000 ppm) animals but was not considered an adverse effect, as urinary and blood 

chemistry did not suggest dehydration. The mean absolute weight of the kidneys was 

significantly increased in the high-dose group, while the relative weight of the kidneys was 

significantly increased in females of both the mid- and high-dose groups. However, this change 

did not correlate to gross or microscopic changes in the kidney and therefore is not considered an 

adverse effect. The mean relative weights of the brain and adrenal glands were significantly 

increased in high-dose males, which are attributed to the weight loss observed in these animals.

The neurological observations revealed no signs of a dose-dependent relationship. However, no 

statistical tests were performed on the neurological data. Other clinical signs, such as alopecia 

and an injury of the right forelimb, were observed in the high-dose group, but were isolated, 

spontaneous in nature, and reflected the natural range of variation.

The LOAEL is 5,000 ppm (285.2 mg/kg body weight/day in males; 338.6 mg/kg body 

weight/day in females), based on decreased body weight and body weight gain, food and water 

consumption, and changes in clinical urinary and blood chemistry. The NOAEL is 1,000 ppm 

(64.1 mg/kg body weight/day in males; 91.0 mg/kg body weight/day in females).

This 90-day oral toxicity study in the rats is Acceptable/Guideline and satisfies the guideline 

requirement for a 90-day oral toxicity study (OPPTS 870.3100; OECD 408) in rats.

870.3200 Subchronic (21-day dermal) Toxicity – Rat 

In a subchronic dermal study (MRID 00155989), Glokill 77 (78.5% a.i., batch TS-704) was 

administered dermally to groups of Sprague-Dawley rats (5/sex/dose) at concentrations of 0, 100, 

500 or 1000 mg/kg/day for 21 days. The test material was used undiluted as supplied. One group 

served as controls and was treated with sterile distilled water in similar fashion as the test 

compound-treated animals. The test compound was held in contact with the skin by a porous 

gauze dressing covered with an Elastoplast elastic adhesive bandage. At the end of each 6-hour 

exposure period the bandage and dressing were removed and the exposure site washed and dried.

All animals survived the study. No toxic signs were reported except for local dermal irritation, 

which was dose-related and increased in severity with the duration of the study. All animals 
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gained weight during the study; however, all groups of treated males gained less weight than 

corresponding controls. Male weight gain in all groups was approximately 70% of the control 

male weight gain. The weights observed for all three treatment groups was within the range 

normally observed in the investigators’ laboratory, and therefore were not considered treatment 

related. Weight gain was comparable in control and treated females.

No difference in food consumption was reported between control and treated males, but during 

week 1, the mid and high-dose female food consumption was significantly decreased (p < 0.05) 

when compared to the controls. No intergroup difference in water consumption was reported.

Mean corpuscular volume was reduced in the low and high-dose males, and hemoglobin was 

reduced in the low and high-dose females, but the reductions were not considered biologically 

significant since they were within the normal range of values for Sprague-Dawley rats in the 

investigators’ laboratory.

The following statistically significant changes were noted in the treated animals when compared 

to the controls (p <0.05), including increased protein in mid and high dose males and high dose 

females, increased sodium in all treated males, increased phosphate in mid and high dose 

females, increased AST in mid and high dose males, decreased A/G ratio in mid and high dose 

males and high dose females, and decreased chloride in mid and high dose females. These 

changes were considered biologically insignificant because the values observed were within the 

range observed in the animals used in the hematology and biochemical screens. 

Except for multifocal scab formation at treatment sites at all dose levels, no macroscopic 

abnormalities were reported. Absolute adrenal weight was significantly decreased in low and 

high-dose males and was reported to be due to two control animals with high adrenal weights. 

No difference was reported in relative organ weights. Treatment-related histopathological 

changes were reported at treated skin sites, but in no other tissues examined. Histopathological 

findings included dose-related epidermal ulceration, acanthosis and dermal inflammatory 

infiltration with occasional necrosis and hemorrhage in the treated animals. 

Based on the dose related epidermal ulceration and dermal inflammation reported at the treated 

skin sites, the dermal LOAEL is 100 mg/kg/day, and the dermal NOAEL is not obtained in 

this study. The systemic NOAEL is 1000 mg/kg/day, the highest dose tested (HDT), and no 

LOAEL for systemic toxicity was established.

This study is classified Minimum.

870.3250 Subchronic (90-day dermal) Toxicity – Rat

(1) In a subchronic dermal study (MRID 41858301), Vanicide TH (96.6% a.i.) was administered 

dermally to groups of Crl:CD BR (Sprague Dawley) rats at concentrations of 0, 10, 30 or 100 

mg/kg/day. An area from the shoulders to the lumbar region was clipped and divided into 

quadrants. Daily applications were rotated from quadrant to quadrant. After the material was 

applied with a gauze patch, the patch was wrapped with COBAN. Material was left in contact 

with the skin for 6 hours and afterward, the residual material was removed with a paper towel 

and was washed with reverse osmosis water. This procedure was repeated for 5 days a week for 
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the next 13 weeks. The test material was applied to approximately 10% of the body surface area 

in one of the prepared quadrants.

Three females died during the study (1 control, 1 mid and 1 high dose). The death in the control 

animal was caused by renal and urinary bladder problems and were believed to be associated 

with dosing procedures in the treatment groups. In addition, all high dose animals were sacrificed 

on Study Day 36 because of the severity of the dermal irritation, including erythema, eschar, 

desquamation, necrosis, exfoliation and ulceration. Females in the high dose group were reported 

to have the most severe dermal lesions, and no healing was observed after the weekend periods 

when the test material was not administered. Some healing was present after the weekends in 

animals in groups 2 and 3. Severe erythema with eschar, as well as exfoliation, necrosis, 

desquamation and ulceration, were reported in the mid dose animals, while slight erythema with 

eschar was observed for low-dose animals. 

A statistically significant decrease (7%) in body weight was reported for males in the high dose 

group when compared to controls. Although there was no statistical significance in mean body 

weights in the low and mid dose groups, there appeared to be a linear response to the dose of the 

test material when these groups were compared to controls. No differences in mean body weights 

were reported for females in any of the treated groups when compared to controls. 

In the mid and high dose males, mean weekly food consumption was statistically lower than 

controls on day 14. This was the only reported difference in food consumption reported for 

males. In females, a statistical significance was reported for animals in the mid and high dose 

groups on day 35; however, the significance was the result of an increase in food consumption 

reported for these animals. 

In the interim evaluation, statistically significant differences in hematology were reported in both 

sexes in the high dose group, including lower hemoglobin, hematocrit, and red blood cell counts, 

when compared to controls; platelet counts were higher. In high-dose females, white blood cell 

counts were also higher than controls during the interim evaluation. At the end of the study, no 

significant differences were reported for any of the hematology parameters. 

In all treated males, albumen, calcium, total protein, sodium and chloride values were 

statistically lower than controls at the interim evaluation. Phosphorus values were statistically 

decreased in mid-dose males. Potassium, AST and ALT values were lower than controls in highdose group animals. In females, significant differences reported for albumen, BUN calcium, 

glucose, total protein, sodium, chloride and potassium during the interim. Most of these values 

were higher than controls with the exception of albumen and total protein in high dose animals. 

Terminal serum chemistry values revealed lower albumen, sodium, calcium and total protein 

values in low- and mid-dose males. Low-dose males also had lower chloride and potassium 

levels when compared to controls. In females, a few clinical chemistry alterations were reported, 

including increased phosphorus and decreased bilirubin and cholesterol in mid-dose group, when 

compared to controls. Decreases in total protein and cholesterol were reported in low-dose 

females. 

No significant differences were reported for organ weights. Relative increases were reported for 

liver and lung weights in females without statistical significance when compared to controls.
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Histologically, there were no treatment related lesions reported with the exception of those 

reported for the skin. There was an increased incidence in hyperplasia and hyperkeratosis of the 

epidermis of the skin in both sexes. Sebaceous gland hyperplasia and denial inflammatory cell 

infiltrations were also increased; other lesions included eschar formation, focal dermal fibrosis, 

focal epidermal necrosis and focal sebaceous gland necrosis.

The dermal NOAEL is < 10 mg/kg/day, the lowest dose tested (LDT); the dermal LOAEL is 

10 mg/kg/day, based on dermal irritation and histological dermal lesions characterized by 

hyperplasia, hyperkeratosis, inflammation, sebaceous gland hyperplasia and eschar formation.

Observations made with regard to serum chemistry and hematology values in both sexes appear 

to be incidental findings that are not biologically significant. No significant differences were 

reported for the hematology values at the end of the study and the serum chemistry values that 

were statistically significant at both the interim and terminal evaluations, were within the range 

of normal values. The systemic NOAEL was 30 mg/kg and the systemic LOAL was 100 

mg/kg, based on severe dermal irritation in both sexes and decreased body weight reported in 

high dose males. At the highest dose tested, both sexes of animals had to be sacrificed on day 36 

due to the severity of the dermal lesions.

This study is classified Minimum.

(2) In a subchronic dermal study (MRID 41483002), groups of Crl:CD(SD)BR rats 

(10/sex/group) received the test material HHT (78.5% a.i.) to the clipped dorsal area at doses of 

0, 5, 50, or 250 mg/kg/day 6 hours/day, 5 days/week for 13 weeks. During the exposure period, 

the application sites were covered with semi-occlusive bandages and animals were fitted with 

Elizabethan collars to minimize ingestion of the test chemical. The test site was not washed 

between doses. 

No deaths were reported during the study. The clinical signs observed during the study included 

periorbital, perianal, and cranial fur staining in all groups; yellow staining at the applications site 

in animals from low- and mid-dose groups. Skin reactions at the applications site were observed

in animals from mid- and high-dose groups, including erythema scored as very slight to severe

with increase in incidence and severity in high-dose animals. Additionally, edema was present 

and characterized as being very severe to moderate in high-dose animals; whereas, only isolated 

incidences of edema were reported in mid-dose group. Occasional incidences of erythema were 

observed in females in the low-dose group.

Statistically significant differences were found in blood chemistry values from individual 

animals, including increased alanine aminotransferase (one low-dose male), increased 

phosphorous (one low-dose female) and increased chloride (one low-dose female). In mid-dose 

group, blood chemistry parameters were increased in two animals, one female had increased 

sodium and one male had increased chlorine levels. In high-dose group, one female had elevated 

glucose levels and one male had elevated sodium levels.

Microscopically, there was an increase in the incidence of epidermal hyperplasia and ulceration 

of the treated area of the skin in animals of the mid- and high-dose groups. Eighty to 100 percent 
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of both the treated and control animals were found to have peribronchiolar lymphoid hyperplasia 

in the lungs. The significance of the lesions was not discussed.

The dermal NOAEL is 5 mg/kg/day and the LOAEL is 50 mg/kg/day, based on skin lesions 

observed at this level. The systemic NOAEL is greater than 250 mg/kg/day, highest dose 

tested (HDT) and the systemic LOAEL is not established.

This study is classified as Minimum.

Developmental Toxicity 

Adequacy of Database for Developmental Toxicity: The database for developmental toxicity is 

considered incomplete. There are two studies in the Agency’s hazard database to address 

developmental toxicity; both studies are in the rat (MRIDs 41161801 & 41865701). A brief 

summary of each of the studies is provided below. A developmental toxicity study in non-rodent 

species is anticipated to be required for registration review risk assessment, based on the 

currently registered uses for HHT; this study was identified as a data gap in the RED. 

870.3700a Prenatal Developmental Toxicity (Gavage) Study – Rat

(1) In a developmental toxicity study in rats (MRID 41161801), artificially inseminated female 

Sprague-Dawley rats (24/group) were administered HHT (78.5%) by gavage at doses of 0, 250, 

500, and 750 mg/kg/day in deionized water on gestation days 6 through 15. 

One high-dose dam was sacrificed on GD 14. Prior to sacrifice on that day the animal exhibited 

labored breathing, rales, emaciation, piloerection, red staining around the mouth and nose and 

pale extremities. All other animals survived the study.

High dose females exhibited post dosing salivation. Rales, labored breathing, wheezing, and 

tachypnea were observed occasionally in the mid and high dose groups toward the end of the 

dosing period. No other clinical signs were reported.

Maternal body weight gain (p<0.01) and food consumption (p<0.001) was significantly lower in 

the high dose females during the dosing period than the controls. 

Stomach lesions, characterized by ulceration and/or scarring of the mucosa were observed in 14 

of 20 high dose females, including the dam sacrificed on day 14. No gross abnormalities were 

reported in the other dosage groups.

The data did not demonstrate any differences between the control and treated dams with respect 

to pregnancy rates, number of corpora lutea, implantation sites, number of live fetuses, or early 

and late resorptions. There were no abortions and no premature deliveries. In addition, those 

dosage levels did not produce any developmental toxicity as measured by fetal pup weight, 

external, or visceral, abnormalities. There were increased incidences of vestigial 14th ribs and 

retarded ossification of the vertebral thoracic centra which appeared to be dose-related. However, 

since they were not statistically significant, and the incidence of these abnormalities is highly 

variable in rats, they are not considered treatment-related.
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The maternal NOAEL is 500 mg/kg/day and the LOAEL is 750 mg/kg/day, based on 

decreased body weight gain, ulcerations and/or scarring of the stomach mucosa. The 

Developmental toxicity NOAEL is greater than or equal to 750 mg/kg/day, the highest dose 

tested (HDT).

This study is classified as Minimum.

(2) In a developmental toxicity study in rats (MRID 41865701), Vanicide TH (96.6% a.i.) was 

administered via gavage to groups of female Crl:CD BR Sprague-Dawley rats (25/dose) at 

concentrations of 0, 10, 75 or 150 mg/kg/day from day 6 through 15 of gestation. 

Mortality was observed in the control (1/25), mid-dose (2/25) and high-dose (6/25) groups but 

these were thought to be associated with incorrect gavaging technique. 

Body weight gain was significantly reduced in the high-dose group (39%) when compared with 

the control animals. Food consumption was higher for the low-dose and mid-dose groups 

through the dosing period and for the low-dose group during the post dosing period. 

No treatment related lesions were observed in the maternal animals at sacrifice. Lesions observed 

in the cervical lymph nodes, liver, lung, kidney, skin and fur were reported as either single 

observances or at incidences that would not suggest an association with the compound. 

Post implantation losses were higher in the treatment groups as compared with the controls but 

only the low-dose group was statistically significant. 

No differences were reported for fetal body weights when control groups were compared with 

the treatment animals. External variations reported included protruding tongue; swollen hind 

paws with hematoma and stunted fetuses but there was no statistical significance in the treatment 

groups for the above mentioned observations. Malformations such as encephaly, micrognathia, 

omphalocele, and thread like tail were observed in the control, low-dose and mid-dose groups. 

No such malformations were seen in the high-dose group. An increase in the incidence of 

hypoplastic sternebrae was reported for animals in the low- and mid-dose groups. There was a 

statistically significant increase in both the fetal and litter incidence of this anomaly. The fetal 

incidence of unossified sternebrae was statistically increased in the mid-dose group when 

compared to controls but this could be an incidental finding. Visceral variations were observed 

for all groups with dilated renal pelvises and convoluted and/or distended ureters being the most 

common variations observed. There was a statistically significant increase in this observation in 

the high-dose pups and a treatment related trend was observed for the occurrence of dilated renal 

pelvises and for bilateral convoluted ureters. 

Based on the results of this study, the maternal NOAEL was 75 mg/kg/day and LOAEL was 

150 mg/kg/day, based on decreased body weight gain. The developmental NOAEL was <10 

mg/kg/day, the lowest dose tested (LDT), based on the observed significant positive trend in the 

incidence of bilateral convoluted ureters and dilated renal pelvises. 

This study is classified Supplementary. However, historical control data should have been 

provided to determine whether the renal observations in the pups were treatment-related.
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Reproductive Toxicity

Adequacy of Database for Reproductive Toxicity: The database for reproductive toxicity is 

considered incomplete. There are no reproductive toxicity studies in the Agency’s hazard 

database; such a study is anticipated to be required for registration review risk assessment, based 

on the currently registered uses for HHT. This study was identified as a data gap in the RED and 

is part of the data required by the post-RED DCI issued on May 12, 2010. 

Chronic Toxicity 

Adequacy of Database for Chronic Toxicity: The database for chronic toxicity is considered 

incomplete. There are no chronic toxicity studies in the Agency’s hazard database; these studies 

are anticipated to be required for registration review risk assessment, based on the currently 

registered uses for HHT. The chronic studies were identified as data gaps in the RED and are 

part of the data required by the post-RED DCI issued on May 12, 2010. 

Carcinogenicity 

Adequacy of Database for Carcinogenicity: The database for carcinogenicity is considered 

incomplete. There are no carcinogenicity studies in the Agency’s hazard database; these studies 

are anticipated to be required for registration review risk assessment, based on the currently 

registered uses for HHT. The carcinogenicity study were identified as data gaps in the RED and 

is part of the data required by the post-RED DCI issued on May 12, 2010. 

Mutagenicity

Adequacy of Database for Mutagenicity: The database for mutagenicity is considered adequate 

for the currently registered uses. Several mutagenicity studies have been submitted and reviewed 

by the Office of Pesticide Programs (OPP) and found acceptable, except for a few in vitro

studies. HHT is found to be mutagenic in a few in vitro studies (e.g., chromosome aberration 

assay and UDS assay) but not in the corresponding in vivo studies. The summaries of these 

studies are provided below. 

Gene Mutation

(1) In a bacterial reverse mutation assay (MRID 41231702), following a range-finding toxicity 

testing with TA98 (only) at doses up to 5000 μg/plate, triplicate cultures of all five Ames strains 

(TA1535, TA1537, TA1538, TA98, TA100) were exposed to Triazine (78.5%) for 72 hours 

(extended from the customary 48 hours because triazine is bacteriostatic, thus slowing growth of 

revertent colonies) at each of five dose levels (0.32, 1.6, 8, 40, and 200 μg/ plate), both in the 

absence and presence of a mammalian metabolic activation system consisting of the liver 

microsomal fraction (S9) prepared from male Fischer 344 rats induced by Aroclor 1254 and 

containing 44 mg protein per mL, plus generating cofactors. The entire experiment was repeated.

In both experiments, the test substance consistently reduced background lawns at the HOT, 200 

μg/mL, in the absence of activation but with one exception did not induce significantly increased 
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revertent colony counts. The exception was a significant F-value (p < 0.05) calculated for 

inactivated TA1537 cultures, derived from a wider-than-usual variation in mean numbers of 

revertents on test plates (3.3 to 7.7) compared to the concurrent mean control value (4.7). This 

was discounted by the investigator because there was neither a doubling of revertent rate nor 

evidence of a dose-relationship. Hence, the investigator concluded that triazine was not 

mutagenic in the Ames testing at levels up to levels of toxicity.

(2) In a reverse gene mutation assay in bacteria (MRID 47284305), strains TA1535, TA100, 

TA102, TA 1537, TA 98 of S. typhimurium and E.coli WP2 urvA were exposed to Protectol HP 

(purity not provided, Batch No.: PK95/222) in water at the following concentrations: 0, 100, 500, 

2500, 5000, 7500 g/plate in the presence and absence of mammalian metabolic activation using 

the plate-incorporation method for strains TA1535, TA100, TA1537, and TA98; and 0, 25, 50, 

100, 200, and 400 g/plate in the presence and absence of mammalian metabolic activation using 

the plate-incorporation and preincubation method for strains TA1535, TA100, TA1537, TA98, 

TA102 and E.Coli WP2 uvrA.

Protectol HP didn’t induce any dose-dependent increases in mean revertants/plate in any strains 

over all concentrations and conditions. The positive controls induced the appropriate responses 

in the corresponding strains. There was no evidence of induced mutant colonies over 

background. There was inconsistency in the results reported for the TA102 plate incorporation 

test; TA102 +S9 did not have a clear positive control response, thus, a new test was conducted 

that elicited an appropriate increase in revertant colonies. This study is classified as 

Unacceptable/Non-guideline (upgradable) due to the lack of detailed description of the test 

material (such as no purity information provided).

(3) In a mammalian cell gene mutation assay at the HPRT locus (MRID 47284303), Chinese 

Hamster V79 cells cultured in vitro were exposed to Protectol HT (79% aqueous solution, batch # 

1157) in deionized water at concentrations of 1.6, 3.1, 6.3, 12.5, 25, or 30 μg/mL,-S9 and at 

concentrations of 1.6, 3.1, 6.3, 12.5, 20, or 25 μg/mL, +S9 for a period of 4 hours. 

Cultures exposed to the test material did not induce dose-dependent increases in the number of 

mutant colonies per 106cells and the mutant frequencies remained within the range of historical 

negative and solvent control values. The positive controls induced the appropriate response.

Mutation frequencies three times above the historical/corresponding negative and/or solvent 

controls, a criterion for a positive response, were not observed in cell cultures treated with 

Protectol HT at any concentration. Therefore, Protectol HT was considered non-mutagenic under 

the conditions of this assay.

This study is classified as Acceptable/Guideline and satisfies the guideline requirement for Test 

Guideline OPPTS 870.5300, OECD 476 for in vitro mutagenicity (mammalian forward gene 

mutation) data. 

Cytogenetics

(1) In an in vitro mammalian cell cytogenetics chromosome aberration assay (MRID 47284302), 

Chinese Hamster V79 Cells (CHC) were exposed to Protectol HT (79 g per 100g aqueous 

solution, Batch No. Partie-Nummer 1157) dissolved in deionized water (10% v/v) at 
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concentrations of 0, 2.5, 5, 10, 20, 30, or 40 μg/mL with and without metabolic activation (S9-

mix) for 4 hours. 

Protectol HT was tested up to cytotoxic concentrations, as determined by an initial range-finding 

study. The range-finding study indicated that the test substance had clastogenic effects after 4 

hours; therefore, a second experiment with a longer exposure time was not performed. At 

concentrations of 20, 30, and 40 μg/mL the number of cells was reduced to 58, 56, and 33% of 

the concurrent solvent controls –S9; and 61, 45, and 41% of solvent controls +S9, respectively. 

At a concentration of 30μg/mL -S9, the number of cells in metaphase was decreased to 45% of 

the control value. Greater test concentrations (30 μg/mL and 40 μg/mL +S9 and 40 μg/mL -S9) 

were not evaluated for mitotic indices, chromosomal aberrations, or polyploidy since the test 

substance was highly toxic at these levels, as shown by the decreased number of metaphase cells.

Dose-dependent increases in aberrant cells, excluding gaps, occurred at doses of 10, 20, and 30 

μg/mL -S9 and at a concentration of 20μg/mL, +S9. A biologically relevant increase in the 

number of cells exhibiting exchanges occurred at concentrations of 10, 20, and 30 μg/mL –S9 

and 20 μg/mL +S9, as compared to solvent controls. No dose-related increases in the rate of 

polyploidy were found after test substance treatment at any concentration ± S9. Positive controls 

induced the appropriate response. There was evidence of chromosome aberrations induced by 

the test material over background incidence rates. Protectol HT is considered to be 

clastogenic in in vitro chromosomal aberration assay in Chinese Hamster V79 Cells in the 

absence as well as presence of S9 activation.

This study is classified as Acceptable/Guideline and satisfies the guideline requirement for Test 

Guideline in vitro mammalian cytogenetics chromosome aberration OPPTS 870.5375; OECD 47 

in cultured Chinese hamster V79 in vitro cytogenetic mutagenicity data. 

(2) In an NMRI mouse bone marrow micronucleus assay (MRID 47284301), 6 males/dose were 

treated once, intraperitoneally, with Protectol HT (79% a.i., Partie-Nummer 1157) at doses of 0, 

37.5, 75, or 150 mg/kg body weight. Bone marrow cells were harvested at 24 hours posttreatment for all dose levels, and 48 hours post-treatment for the negative control and 150 mg/kg 

treatment dose. The vehicle was deionized water. 

The dose range used for the micronuclei was informed by a preliminary study in which 

unscheduled deaths were noted in male and female mice at doses ≥ 200 mg/kg. In the main 

study, there were signs of toxicity in treated animals (i.e., reduction of spontaneous activity, 

eyelid closure, apathy, abdominal position, and death). A slight increase in micronuclei was 

noted in the high-dose animals, indicating cytotoxic effects of the test substance. This increase, 

however, was not higher than the range of negative control values and was not found to be 

statistically significant using the Mann-Whitney test. Protectol HT was tested at an adequate 

maximum dose based on clinical signs of toxicity, lack of unscheduled deaths, and evidence of 

bone marrow cytoxicity. The positive control induced the appropriate response. A significant 

increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow was not 

observed at either analysis time point.

This study is classified as Acceptable/Guideline and satisfies the guideline requirement for Test 

Guideline OPPTS 870.5395; OECD 474 for in vivo cytogenetic mutagenicity data. 
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(3) In a mammalian bone marrow chromosome aberration test in mouse (MRID 41231701), 

Triazine (78.5%) was administered to groups of CD-1 mouse (5/sex/group) by gavage in a single 

dose at 200, 400, and 800 mg/kg, following a rang-finding study (at doses up to 2000 mg/kg) and 

were sacrificed 24, 48, or 72 hours later. Control groups received 0.9% saline (solvent control), 

or cyclophosphamide (CPA, positive control); the latter sacrificed only at 24 hours. 

In the range-finding test, deaths occurred at 1200 and 2000 mg/kg (respectively, 2 of 3 animals 

and 3 of 3 of each sex), but no mortalities at 800 mg/kg or below, providing an estimated LD50 of 

approximately 1000 mg/kg. Based upon the (OECD) convention of applying 80% of the LD50 as 

the MTD for this type of study, the HDT for the main study was selected as 800 mg/kg, with two 

lower doses of 400 and 200 mg/kg.

In the micronucleus assay itself, two high-dose (800 mg/kg) animals (one of each sex) died 

before their scheduled sacrifice at 48 hours. No cytotoxicity, as measured by reduction in 

PCE/NEC ratios, was found in any nabam-treated group. Random variation around control 

values for numbers of micronuclei was found at all sacrifice times and in both sexes of test 

animals. A singular statistically significant increase in micronuclei over concurrent control was 

calculated for the 400 mg/kg male group sacrificed at 72 hours (0.14 vs. 0.02). This increase was 

considered to be of no biological significance since it fell within solvent control ranges at other 

sampling times (notably 24 hours when optimally most of the micronuclei would be visualized).

Hence, the investigator concluded that triazine did not induct micronuclei in bone marrow cells 

of mice treated orally up to a nominal dose (800 mg/kg) considered a MTD by OECD (80% of 

the LD50). 

Other Genotoxicity

(1) In a primary rat hepatocyte unscheduled DNA synthesis (UDS) assay (MRID 41262301), 

hexahydro-l, 3, 5-tris(2-hydroxyethyl)-s-triazine was tested at nine dose levels ranging from 

0.0001 to 1.0 μL/mL in three replicate plates, based on the results of the preliminary cytotoxicity 

the test article. 

Two UDS and parallel cytotoxicity assays were conducted with nine doses of the test material 

(0.0001 to 1.0 μL /mL). Because of unspecified technical difficulties, the first assay was 

terminated.

In the repeat assay, the two highest test doses (0.3 and 1.0 μL/mL) induced marked cytotoxicity 

(85%) and were, therefore, not scored for UDS activity. The five levels selected for the 

evaluation of UDS induction were 0.001, 0.003, 0.01, 0.03, and 0.1 μL/mL. The highest test 

material dose scored for UDS (0.10 μL/mL) induced a marked increase in the net nuclear grain 

count compared to the solvent control. Similarly, the percentage of cells with ≥5 net nuclear 

grains (NGC) was markedly higher at this level compared to the solvent control value. However, 

the evidence for a genotoxic effect was confined to the 0.10 μL/mL dose group. The mean net 

nuclear grain counts and percentage of cells with ≥5 net nuclear grains for hepatocytes exposed 

to 0.001, 0.003, 0.01, or 0.03 μL/mL of the test material, although higher than the solvent 

control, did not indicate a positive or a dose-related response. The study author concluded that 
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hexahydro-l,3,5-tris(2- hydroxyethyl)-s-triazine induced an equivocal positive response in this 

test system.

This study is classified as Unacceptable. In the absence of a dose-related effect, confirmation of

a “significant” increase at a single dose is necessary to conclude a positive response in the UDS 

assay. However, the positive response was not dose related, was limited to the 0.l0 μL/mL 

treatment group, and the results were not confirmed. In addition, the study author failed to 

provide information on test material purity, the batch number of the assayed sample, and 

analytical data to verify actual concentrations used in the assay. Therefore, it was concluded that 

the study is unacceptable, but the test material is classified as presumptively genotoxic in this 

test system.

(2) In an unscheduled DNA synthesis (UDS) study (MRID 43020001), following preliminary 

cytotoxicity testing (by lactate dehydrogenase, LDH, release determinations), triplicate coverslip 

cultures (per does) of rat hepatocytes were exposed to hexahydro-l, 3, 5-tris(2-hydroxyethyl)-striazine for 18-20 hours to a series of nine concentrations of test article (ranging from 0.001 to 

0.30 μg/mL), together with a constant dose of tritiated thymidine (HTdr, 10 μCi/mL). Other 

cultures were treated with 7, 12-dimethylebenz(a)anthracene (DMBA, 3 and 10 μg/mL), to serve 

as positive controls. 

For the UDS assay, examination of the fixed and stained cells which had been treated at doses of 

0.15, 0.2, 0.25, and 0.3 μg/mL revealed that these could not be evaluated for UDS “because of 

excessive cytotoxicity”, resulting in relative cell survivals less than 35%. Although none of the 

remaining (lower) test article doses (0.01, 0.03, 0.05, 0.07, and 0.1 μg/mL) caused a significant 

increase in mean NNC, according to the authors’ criteria established for declaring a positive 

result (i.e., an increases of at least five counts over solvent control), there was a dose-related 

increase trend in both mean NNC, as well as percentage of cells showing DNA repair. On the 

other hand, DMBA-treated cultures showed a definitively significant mean NNC (>5 counts) in 

99% of cells in repair. 

Hence, the authors concluded that the test article was not considered positive according to their 

criterion for a genotoxic response.

This study is classified as Unacceptable, though “equivocally (presumptively) positive”, 

because of slight, but dose-related, increases in both mean net nuclear silver grain counts (NNG), 

as well as percentage of cells in repair at the usable three highest dosage levels 0.05, 0.07 and 

0.10 μg/mL, but which did not reach the criterion for significance proposed by the investigators, 

namely, increase of 5+ counts over control. Higher doses were stated to be “too toxic to be 

evaluated for UDS” (as suggested by LDI4 release at 30-60% lethality), necessitating in the 

reviewer’s opinion a repeat assay to resolve this equivocation, together with (l) a finer sequence 

of dosages to recover viable cultures at higher concentrations, (2) testing hepatocytes from a 

female rat, and (3) providing the purity (% a.i.) of the test article.

In reviewing the data base for this substance, revealed a previous UDS study (MRID 41262301), 

conducted by the same laboratory. This study was also classified Unacceptable, requiring 

confirmation of a positive response (increased NNG >5, and increased % cells in repair) at the 

HDT of 0.10 μg /ml.
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Thus, these two comparable assays, when considered together, constitute the recommended 

confirmation of singularly positive results, and may be re-classified ACCEPTABLLE, in 

ratifying that HHT induces UDS (repair) above background at mildly toxic doses (<20% 

lethality).

(3) In an in vivo unscheduled DNA synthesis assay in rat hepatocytes (MRID 47284304), based 

on the mortality observed in a preliminary acute toxicity test, male and female Wistar rats were 

orally (gavage) exposed to Protectol HT (79% aqueous solution, batch # 1157), in deionized 

water, at concentrations of 0, 375, or 750 mg/kg (male) and at 0, 250, or 500 mg/kg (female) for

a period of either 2 or 16 hours. Rats were also exposed to two positive mutagens (DMH and 2-

AAF) at concentrations of 40 mg/kg and 100 mg/kg, respectively. 

Oral administration of Protectol HT did not induce an increase in unscheduled DNA synthesis in 

male and female rat hepatocytes at any concentration tested. No increase in the nuclear grains or 

net grains was observed in hepatocyte cultures exposed for a period of 2 or 16 hours. The 

positive controls elicited the appropriate responses. There was no evidence of induction of 

unscheduled DNA synthesis in rat primary hepatocytes over the background.

This study is classified as Acceptable/Guideline and satisfies the guideline requirement for Test 

Guideline OPPTS 870.5550; OECD 486 for other genotoxic mutagenicity data. 

Immunotoxicity

870.7800 Immunotoxicity Study

Adequacy of Database for Immunotoxicity: The database for Immunotoxicity is considered 

incomplete. There are no Immunotoxicity studies in the Agency’s hazard database. An 

Immunotoxicity study is anticipated to be required for registration review risk assessment, based 

on the currently registered uses for HHT.

Other Toxicological Effects 

There are two in vitro studies submitted for HHT, one is a dermal penetration study using human 

skin and the other is a metabolism study using human blood and cryopreserved hepatocytes. 

Although the in vitro dermal penetration study using human skin is an acceptable study, only one 

in vitro study does not adequately address dermal absorption of HHT. However, there are 

subchronic dermal studies; therefore, an in vivo dermal penetration study is not expected to be 

required. Brief summary of these studies are provided below. 

(1) In an in vitro dermal penetration study (MRID 47353801; also MRID 47281206), [14C]-

formaldehyde-Hexahydro-1,3,5 tris(2-hydroxyethyl)-s-triazine (HHT) (99.0%; batch #209740/05 

[non-radiolabelled]; 84.30%, 210405/011 [radiolabelled]) was administered at a dose of 9.91 

mg/cm2to 8 human skin preparations (split-thickness membranes) (Experiment 1) or 7.95 

mg/cm2to 4 human skin preparations (Experiment 2) that were mounted in diffusion cells 

occluded with a carbon trap and carbon filter. Receptor fluid was collected at hourly intervals 

from 0-8 hours post-application (Experiments 1 and 2), and every 2 hours from 8-24 hours postapplication (Experiment 1 only). The skin was washed and wiped 8 hours after application 
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(Experiments 1 and 2). The skin was tape stripped 8 hours after application (Experiment 2) or 24 

hours following application (Experiment 1). Carbon filters and traps were removed and extracted 

at 8 hours (Experiments 1 and 2) and 24 hours (Experiment 1).

Recovery of the applied dose (mass balance) in Experiment 1 was unacceptable, ranging from 

63.75% to 78.57%. This low mass balance was possibly due to volatile ([

14C]-formaldehyde) 

components in the carbon trap. A second experiment (Experiment 2) was performed to 

investigate the possible volatility of the test article. Recovery of the applied dose in Experiment 2 

was acceptable in 3 out of the 4 samples. In both experiments, the highest levels of radioactivity 

were recovered from the tissue swabs after 8 hours of exposure: 38 and 40% of the applied dose 

in Experiment 1 and Experiment 2, respectively. The next highest levels of radioactivity were 

present in the skin wash and carbon filter and trap. These three metrics combined with the 

radioactivity of the pipette tip, cell wash, unexposed skin, and tape strips yielded the total 

unabsorbed dose: 68 and 90% of the applied dose in Experiment 1 and 2 respectively. The total 

absorbed dose was 2.87% of the applied dose in Experiment 1 and 2.54% percent of the applied 

dose in Experiment 2. Based on radio Mass-Spectrometry, HHT completely degraded in receptor 

fluid and skin samples.

This in vitro study using human skin is ACCEPTABLE, NON-GUIDELINE. This study is 

considered non-guideline because it is an in vitro human skin penetration and distribution study. 

This study does not satisfy the guideline requirements of OPPTS 870.7600 in vivo dermal 

penetration study conducted on rats. 

(2) In an in vitro metabolism study (MRID 47353802; also MRID 47281205), hexahydro-1,3,5-

tris(2-hydroxyethyl)-S-triazine (radiolabeled test item batch #: 210405/012, 81.72% 

radiochemical purity; non-radiolabeled test item batch #: 209740/05, 99% purity) was 

administered to male human blood and cryopreserved hepatocytes at dose levels of 0 or 6.6 μM.

Radioactive recoveries were determined. The chromatograms of non-radiolabeled hexahydro1,3,5-tris(2-hydroxyethyl)-S-triazine confirmed retention time of the parent compound as 10 

minutes and radiolabelled hexahydro-1,3,5-tris(2-hydroxyethyl)-S-triazine showed an impurity 

eluting at 3.5 minutes. Since this impurity was greater than the impurity observed in the parent 

compound, it suggests instability in this study (incubation matrix, stopping solution, and/or 

mobile phase). Chromatograms for media, hepatocytes, and blood showed no parent compound 

remaining, which suggests instability in this study; therefore, it is not possible to establish 

whether any metabolism of hexahydro-1,3,5-tris(2-hydroxyethyl)-S-triazine occurred. 

This in vitro metabolism study in human cells is classified Unacceptable-Nonguideline and 

does not satisfy the guideline requirement [OPPTS 870.7485, OECD 417] because the test 

system was not appropriate, the test material was unstable, and the study greatly deviated from 

the guidelines. 
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Table A2 – Toxicity Profile for HHT

Guideline No./

Study Type

MRID No./

Study Classification Dosing and Animal Information Results

Subchronic Toxicity

870.3100

90-day Oral (Rat)

MRID 41483001

Minimum

Purity 78.5%

Rats (10/sex/group)

0, 10, 50, 100, or 250 mg/kg/day 

(gavage)

NOAEL = 50 mg/kg/day

LOAEL = 100 mg/kg/day, based on 

lymphocytic infiltration in females 

and erosion of gastric mucosa and 

prominence of limiting ridge of the 

stomach in males.

870.3100

90-day Oral (Rat)

MRID 47300901

Acceptable/Guideline

Purity 79%

Rats (10/sex/group)

0, 200, 1000, or 5000 ppm 

(equivalent to ♂: 0, 14.1, 64.1, or 

285.2 mg/kg bw/day; ♀: 0, 21.2, 

91.0, or 338.6 mg/kg bw/day)

(gavage)

NOAEL = 1000 ppm 

(♂: 64.1 mg/kg/day; ♀: 91.0 

mg/kg/day)

LOAEL = 5000 ppm 

(♂: 285.2 mg/kg/day; ♀: 338.6 

mg/kg/day), based on lymphocytic 

infiltration in females and erosion of 

gastric mucosa and prominence of 

limiting ridge of the stomach in 

males.

870.3200

21-day Dermal (Rats)

MRID 

00155989/260195

Minimum

Purity 78.5%

Rats (5/sex/group)

0, 100, 500, or 1000 mg/kg/day

NOAELdermal < 100 mg/kg/day 

LOAELdermal = 100 mg/kg/day 

(lowest dose tested [LDT]), based on 

multifocal scab formation at 

treatment sites and histological doserelated findings (epidermal 

ulceration, acanthosis and dermal 

inflammatory infiltration with 

occasional necrosis and hemorrhage).

NOAELsystemic ≥ 1000 mg/kg/day

(highest dose tested [HDT])

LOAELsystemic not established.

870.3250

90-day Dermal 

Subchronic (Rats)

MRID 41858301

Minimum

Purity 96.6%

Rats (13sex/group)

0, 10, 30, or 100 mg/kg/day

NOAELdermal < 10 mg/kg/day

(lowest dose tested [LDT])

LOAELdermal = 10 mg/kg/day, based 

on the gross observation of dermal 

irritation and histological dermal 

lesions (hyperplasia, hyperkeratosis, 

inflammation, sebaceous gland 

hyperplasia and eschar formation).

NOAELsystemic = 30 mg/kg/day

LOAELsystemic = 100 mg/kg/day, 

based on severe dermal irritation in 

both sexes and decreased body 

weight reported in high dose males.
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Guideline No./

Study Type

MRID No./

Study Classification Dosing and Animal Information Results

870.3250

90-day Dermal 

Subchronic (Rats)

MRID 41483002

Minimum

Purity 78.5%

Rats (10/sex/dose)

0, 5, 50, 250 mg/kg

NOAELdermal = 5 mg/kg/day 

LOAELdermal = 50 mg/kg/day, based 

on the presence of skin lesions

NOAELsystemic > 250 mg/kg/day

(highest dose tested [HDT])

LOAELsystemic not established.

Developmental Toxicity

870.3700a

Developmental 

Toxicity (Rat)

MRID 41161801

Minimum

Purity 78.5%

Rats (24/dose)

0, 250, 500, or 750 mg/kg/day, 

GD 6-15

NOAELmaternal = 500 mg/kg/day

LOAELmaternal = 750 mg/kg/day, 

based on decreased body weight 

gain, ulcerations, and scarring of the 

stomach mucosa.

NOAELdevelopmental ≥ 750 mg/kg/day

(highest dose tested [HDT]).

LOAELdevelopmental not established.

870.3700a

Developmental 

Toxicity (Rat)

MRID 41865701

Supplementary

Purity: 96.6%

25 rats/group

0, 10, 75 and 150 mg/kg/day, GD 

6-15

NOAELmaternal = 75 mg/kg/day

LOAELmaternal = 150 mg/kg/day, 

based on decreased body weight gain

LOAELdevelopmental ≤ 10 mg/kg/day

(lowest dose tested [LDT]), based on 

the observed significant positive 

trend in the incidence of bilateral 

convoluted ureters and dilated renal 

pelvises.

NOAELdevelopmental not established.

Reproduction Toxicity

870.3800

Reproduction

A reproduction toxicity study is not available for HHT.

Chronic Toxicity

870.4100

Chronic Toxicity

A chronic toxicity study is not available for HHT.

Carcinogenicity

870.4200

Carcinogenicity

A carcinogenicity study is not available for HHT.

Mutagenicity

870.5100

Bacterial reverse 

mutation test

MRID 41231702

Acceptable/Guideline

Purity 78.5%

TA1535, TA1537, TA1538, 

TA98, or TA100

up to 200 μg/plate with and 

without S9 metabolic activation

Negative

870.5100

Bacterial reverse 

mutation test

MRID 

00155991/260195

Unacceptable

Purity 78.5%

Strains TA1535, TA1537, 

TA1538, TA98, or TA100

0, 0.16, 0.8, 4, 20, or 100 

μg/plate; ±S9

Positive

Positive in TA96 with activation and 

in TA1538 with and without 

activation.
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Guideline No./

Study Type

MRID No./

Study Classification Dosing and Animal Information Results

870.5100

Bacterial reverse 

mutation test

MRID 47284305

Unacceptable/Nonguideline 

(upgradable)

Purity not provided

strains TA98, TA100, TA1535, 

TA1537, of S. typhimurium: 0, 

100, 500, 2500, 5000, 7500 

g/plate; ±S9

strains TA98, TA100, TA102; 

TA1535, TA1537, of S. 

typhimurium and E.coli WP2 

urvA: 0, 25, 50, 100, 200, and 

400 g/plate; ±S9

Negative

870.5300

Mammalian cell gene 

mutation test

MRID 47284303

Acceptable/Guideline

Purity 79% aqueous solution

Chinese Hamster V79 cells 

(CHC)

1.6, 3.1, 6.3, 12.5, 25, or 30 

μg/mL,-S9; 1.6, 3.1, 6.3, 12.5, 20, 

or 25 μg/mL, +S9; for a period of 

4 hours

Negative

870.5375

In vitro mammalian 

chromosome 

aberration test

MRID 47284302

Acceptable/Guideline

Purity 79%

Chinese Hamster V79 Cells 

(CHC)

0, 2.5, 5, 10, 20, 30, or 40 μg/mL; 

±S9 for 4 hours

Positive

870.5385

In vivo mammalian 

bone marrow 

chromosome 

aberration test (mouse)

MRID 41321501

Unacceptable

Purity 78.5%

5/sex/group

0, 200, 400, or 800 mg/kg (80% 

of LD50)

Negative

870.5385

In vivo mammalian 

bone marrow 

chromosome 

aberration test (mouse)

MRID 41231701

Acceptable/Guideline

Purity 78.5%

5/sex/dose

0, 200, 400, and 800 mg/kg; 

gavage; marrow cells were 

harvested at 24, 48, or 72 hours 

post-treatment.

Negative

870.5385

In vivo mammalian 

bone marrow 

chromosome 

aberration test (mouse)

MRID 47284301

Acceptable/Guideline

Purity 79%

6 male mice/dose

0, 37.5, 75, or 150 mg/kg; 

intraperitoneally; bone marrow 

cells were harvested at 24 hours 

post-treatment for all dose levels, 

and 48 hours post-treatment for 

the negative control and 150 

mg/kg treatment dose.

Negative
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Guideline No./

Study Type

MRID No./

Study Classification Dosing and Animal Information Results

870.5385

In vivo mammalian 

bone marrow 

chromosome 

aberration test (rat)

MRID 00155992

Unacceptable

Rat micronucleus cells

Purity 78.5%

Intragastric intubation, dermal 

application, or subcutaneous 

injection; 2 equal doses, separated 

by 24 hours, of 15, 60, 240, or 

960 mg/kg

Negative

870.5550

Unscheduled DNA 

synthesis

MRID 41262301 

MRID 43020001

Unacceptable

Purity 78.5%

Rat hepatocyte cells

0, 0.001, 0.003, 0.01, 0.03, and 

0.10 μL/mL

0, 0.001, 0.03, 0.01, 0.03, or 0.1 

μg/mL

Positive

These 2 studies, when considered 

together, constitute the recommended 

confirmation of a singularly positive 

results, based on HHT inducing UDS 

(repair) above background at mildly 

toxic doses (<20% lethality).

870.5550

(In vivo) Unscheduled 

DNA synthesis 

MRID 47284304

Acceptable/Guideline

Purity 79% aqueous solution

Rat hepatocyte cells

♂: 0, 375, or 750 mg/kg; 

♀: 0, 250, or 500 mg/kg; gavage; 

either 2 or 16 hours.

Negative

Metabolism

870.7485

(In vitro) Metabolism

and Pharmacokinetics

MRID 47353802

MRID 47281205

Unacceptable

Purity 81.72% (radiolabeled); 

99% (non-radiolabeled)

Human blood and cryopreserved 

hepatocytes

0, 6.6 μM

The test system was not appropriate, 

the test material was unstable, and 

the study greatly deviated from the 

guidelines.

Dermal Penetration

870.7600

(In vitro) Dermal 

penetration

MRID 47353801

MRID 47281206

Acceptable/Nonguideline

Purity 99.0% (non-radiolabelled); 

84.30% (radiolabelled)

Human skin

9.91 mg/cm2to 8 human skin 

preparations (split-thickness 

membranes) (Experiment 1) or

7.95 mg/cm2to 4 human skin 

preparations (Experiment 2) 

The total absorbed dose was 2.87% 

of the applied dose in Experiment 1 

and 2.54% percent of the applied 

dose in Experiment 2. Based on radio 

Mass-Spectrometry, HHT completely 

degraded in receptor fluid and skin 

samples. 

However, an in vitro study only does 

not adequately address dermal 

absorption of HHT.
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Appendix B Environmental Fate

Environmental Fate and Transport Properties of Hexahydro-1, 3, 

5,-tris(hydroxyethyl)-s-triazine (HHT) 

Water and Sediment

Hydrolysis

EPA has reviewed four hydrolysis studies. These studies which are summarized below give 

conflicting results regarding hydrolysis at high pH. EPA anticipates the need to require a new 

hydrolysis study to address the rate of degradation and formation of any pertinent degradates.

1. MRID#: 47353803: This study was conducted as the pH changed from 1 to 11.35 to estimate 

the stability of HHT at different pHs. The degradation of HHT was followed by changes 

observed in the HPLC chromatograms. It was observed that: 

1) At pH 1, HHT degraded instantly (t= 0).

2) HHT was stable at pH 11.35 but less so at pH 7.2. 

3) At pH 4, HHT degraded fast but the degradation time was measureable.

The temperature of the study was kept at about 37 ̊C. This study showed that HHT is not 

stable in acidic conditions, but is stable under basic conditions.

2. MRID# 43181001: In this study, hydrolytic half-life measured were: 3.2 days at pH 5, 50 

days at pH 7, and 302 days at pH 9. The temperature of the study was 25 ̊C. Hydrolytic 

degradate characterized was formaldehyde. Maximum level (percent) of formaldehyde was 

100, 31 and 20 at pHs 5, 7, and 9.

3. In the third study (Bakke et al study, 2001; open literature study): it was shown that HHT 

degraded fast at –pH 9.5 and 10.9 and 8.0 (T = 22 C).The half-life were: 3.4 hours, 16 

minutes and 32 seconds respectively. When measured at 60 C, the half-life were: 3.1 minutes 

and 6.3 seconds for pH 10.9 and 9.5 respectively. Thus both studies indicate short hydrolytic 

half-lives at neutral to basic pHs.

4. MRID# 48741001: This hydrolysis study in aqueous metalworking fluid was conducted to 

determine the rate of release of formaldehyde when HHT was used in an aqueous MWF 

mixture containing 4, 5, and 6% HHT. The study was conducted at 25, and 35 ̊C. About 30% 

loss of released formaldehyde was noted. No rationale was provided for 30% loss of 

formaldehyde. Incomplete study. 
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Ready Biodegradability:

A ready biodegradability study by Voets et. al, 1975 on HHT showed that a when 70 mg/L of 

HHT was tested with 1/10 th of its intended use concentration, under aerobic and anaerobic 

conditions. 100% of HHT biodegraded; formaldehyde was the only degradation product

measured.

In order to characterize the potential for biodegradation, the Agency anticipates needing 

additional information on the formation and decline of degradates.

Adsorption

MRID#: 47281203: A study on the Estimation of Adsorption Coefficient (Koc) for Mergal 

KM 200 (a product containing 76. % HHT) was conducted on soil and Sewage Sludge using 

High Performance Liquid /chromatography (HPLC). The study was designed based on the 

OECD Test Guideline No. 121.

The results of the study indicated Log Koc could not be determined for Mergal KM 200 

(which contains 76% HHT) as the active showed a peak with the retention that was smaller 

than the retention time of urea which was used as a reference substance. Study authors made 

a tentative interpretation: Test substance is highly water soluble, and with very small 

retention time on the HPLC column, it could indicate that test substance is very mobile on 

soil and sewage sludge systems.

Fate and Transport in WWTP

Activated Sludge Sorption Isotherm: No data was submitted. Data gap.

Activated Sludge Biodegradation: No Data was submitted. Data gap.

Ready Biodegradability: No Data was submitted. Data gap.
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Appendix C Ecotoxicology Profile

Toxicity to Terrestrial Organisms

Birds

The Agency requires one acute-oral study to establish the toxicity of HHT (technical grade active 

ingredient, TGAI) to birds for all registered uses. The preferred test species is either the mallard 

(Anas platyrhynchos) or the northern bobwhite (Colinus virginianus). One available acute-oral 

study indicates that HHT is only slightly toxic to birds (Table C1). Avian dietary toxicity studies 

(northern bobwhite and mallard) are conditionally required for antimicrobial pesticides, 

depending on the avian acute-oral toxicity, pertinent environmental fate characteristics, and a 

potential for exposure. Although not required for the current uses of HHT, the three dietary

studies previously submitted categorize HHT as being practically nontoxic when ingested (Table 

1). An avian precautionary statement is not required on product labels. The guidelines for avian 

acute-oral toxicity (OPPTS 850.2100) and avian dietary toxicity OPPTS 850.2200) are satisfied. 

Table C1. Acute-oral and Dietary Toxicity of HHT to Birds

Test

Species

Test

Type

% ai

tested

Toxicity

Endpoint

Toxicity 

Category

Study

Status

MRID 

No.

Northern 

bobwhite

acute 

oral

83.8 LD50 = 1520 

(mg ai/kg bw)

slightly 

toxic core 43154301

dietary 83.8 LC50 >5620

(ppm)

practically 

nontoxic core 43154302 

dietary ?

(Milidin X-2)

LC50 >5000

(ppm)

practically 

nontoxic supplemental 240113101

Mallard dietary ?

(Milidin X-2)

LC50 >5000

(ppm)

practically 

nontoxic supplemental 240113101

Nontarget Insects 

Toxicity data for beneficial insects (850.3020, 850.3030) are not expected to be required for the 

use patterns of HHT. 

Mammals, Acute and Chronic 

Refer to the human toxicology chapter for details on the available mammalian toxicity studies.
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Toxicity to Aquatic Organisms

Freshwater Fish 

Freshwater Fish, Acute

The Agency requires one acute toxicity study with the TGAI to establish the toxicity of HHT to 

freshwater fish. The preferred test species would be either the rainbow trout (Oncorhynchus 

mykiss), a coldwater fish, or the bluegill (Lepomis macrochirus), a sunfish. For HHT, acute 

studies are available for both the rainbow trout and the bluegill and for the channel catfish 

(Ictalurus punctatus) (Table C2). The acute toxicity values from these studies categorize HHT as 

being slightly toxic to freshwater fish. A precautionary label statement is not required. The 

guideline (OPPTS 850.1075) is satisfied.

Table C2. Acute Toxicity of HHT to Freshwater Fish

Test

Species

% ai

tested

96-h LC50

(mg ai/L)

Toxicity 

Category Study Status MRID No.

Rainbow trout

65.9

(Triadine 10) 41.7 slightly toxic supplemental 247712

?

(Milidin X-2) 71 slightly toxic supplemental 248883

?

(Milidin X-2) 74 slightly toxic supplemental 240113106

Bluegill

?

(Milidin X-2) 39 slightly toxic supplemental 248883

?

(Milidin X-2) 39.8 slightly toxic supplemental 240113106

65.9

(Triadine 10) 77 slightly toxic supplemental 247712

Channel 

catfish

65.9

(Triadine 10) 36 slightly toxic supplemental 247712

The Agency requires one study with the TGAI to establish the chronic toxicity of HHT to 

freshwater fish. The preferred test species is the bluegill sunfish. Data are anticipated to be 

needed for this guideline (fish early-life stage, 850.1400).

Freshwater Invertebrates

The Agency requires one study with the TGAI to establish the acute toxicity (EC50) of HHT to 

freshwater invertebrates. The preferred test species is Daphnia magna, a water flea. Results of 
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two submitted studies are presented in Table 3. Based solely on mortality (LC50), the two 

studies categorize HHT as being moderately toxic to freshwater invertebrates. However, an 

EC50 (based on immobility of exposed daphnids) was not determined in either study. The

guideline requirement (OPPTS 850.1010) is satisfied for current uses. However, a study 

establishing an EC50 (based on mortality and immobility) may be required to support any new 

uses in which HHT is expected to reach the aquatic environment at exposure levels of concern 

for aquatic organisms.

Table C3. Acute Toxicity of HHT to Freshwater Invertebrates

Test

Species

% ai

tested

48-h LC50

(mg ai/L)

Toxicity 

Category Study Status MRID No.

Water flea

65.9

(Triadine 10) 5.4 moderately toxic supplemental 247712

83.8 26.1 slightly toxic supplemental 43175401

The Agency requires one study with the TGAI to establish the chronic toxicity of HHT to 

freshwater invertebrates. The preferred test species is Daphnia magna, a water flea. Data are 

anticipated to be needed for this guideline (aquatic invertebrate life cycle, 850.1300).

Estuarine/Marine Fish and Invertebrates 

The Agency requires acute toxicity testing with estuarine and marine organisms using the TGAI 

when the end-use product is intended for direct application to the marine/estuarine environment 

or the active ingredient is toxic to aquatic organisms and is expected to reach this environment 

via other transport pathways. The preferred test species are the sheepshead minnow (Cyprinodon 

variegatus), mysid shrimp (Mysidopsis bahia), and Eastern oyster (Crassostrea virginica). 

Table 4 presents available data supporting HHT drilling uses in the estuarine/ marine 

environment. Test results indicate that HHT is practically nontoxic to moderately toxic to 

estuarine/marine organisms. The guidelines (OPPTS 850.1025, OPPTS 850.1035, OPPTS 

850.1075) are satisfied. 

Table C4. Acute Toxicity of HHT to Estuarine/Marine Invertebrates

Test Species % ai

tested

96-h LC50 or EC50

(mg ai/L) Toxicity Category Study Status MRID No.

Sheepshead minnow 83.8 >118 practically nontoxic supplemental 43143102

Eastern oyster 83.8 2.3

(shell deposition) moderately toxic core 43175402

Mysid shrimp 83.8 12 slightly toxic supplemental 43143103
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Aquatic Plants 

No data are available. Studies expected to be needed for the TGAI including a toxicity test with a 

vascular species (850.4400) and algal toxicity tests (850.4500 and 850.4550) with four species 

(Anabaena flos-aquae, Navicula pelliculosa, Skeletonema costatum, and Selenatrum 

capricornutum).

Sediment Toxicity

Based on the environmental-fate properties of HHT, sediment toxicity data are not expected to 

be required.
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References

Campbell, S.; Beavers, J. (1994) Triazine: An Acute Oral Toxicity Study with the 

Northern Bobwhite: Lab Project Number: 210/119. Unpublished study prepared by 

Wildlife International Ltd. 19 p. MRID Campbell, S.; Beavers, J. (1994) Triazine: A 

Dietary LC50 with the Northern Bobwhite: Lab Project Number: 210/118. Unpublished 

study prepared by Wildlife International Ltd. 18 p. MRID 43154302

Carson, S. (1968) The Effect of Grotan on Fingerling Fish: Laboratory No. 88969. (Unpublished 

study received Jun 13, 1977 under 1839-59; prepared by Food and Drug Research 

Laboratories, Inc., submitted by Onyx Chemical Co., Jersey City, NJ; CDL:240105-A). 

MRID 123909

Davis, J.; Kernaghan, N. (1994) Acute Toxicity to Rainbow Trout, Oncorhynchus mykiss, under 

Flow-Through Test Conditions: Triazine: Lab Project Number: J9306004E. Unpublished

study prepared by Toxikon Environmental Sciences. 46 p. MRID 43143101

Davis, J. (1994) Acute Toxicity to the Water Flea, Daphnia magna, under Flow-Through Test 

Conditions: Triazine: Lab Project Number: J9306004D. Unpublished study prepared by 

Toxikon Environmental Sciences. 47 p. MRID 43175401

Davis, J. (1994) Acute Toxicity to the Mysid, Mysidopsis bahia, under Flow-Through Test 

Conditions: Triazine: Lab Project Number: J9306004F. Unpublished study prepared by 

Toxikon Environmental Sciences. 46 p. MRID 43143103

Davis, J. (1994) Acute Effect on New Shell Growth of the Eastern Oyster, Crassostrea virginica: 

Triazine: Lab Project Number: J9306004H. Unpublished study prepared by Toxikon 

Environmental Sciences. 49 p. MRID 43175402

Fletcher, D. (1975) Report to De Mille Chemical Corporation: 8-Day Dietary LCI50^ Study with 

Milidin X-2 in Mallard Ducklings: IBT No. 651-07430. (Unpublished study received Sep 

29, 1975 under 21167-2; prepared by Industrial Bio-Test Laboratories, Inc., submitted by 

Demille Chemical Corp., Jersey City, N.J.; CDL: 227630-A). MRID 47528

Fletcher, D. (1973) Report to Demille Chemical Corporation: 8-Day Dietary LCI50^ Study with 

Milidin X-2 in Bobwhite Quail: IBT No. 651-03691. (Unpublished study received May 

14, 1964 under 21167-2; prepared by Industrial Bio-Test Laboratories, Inc., submitted by 

Demille Chemical Corp., Jersey City, N.J.; CDL: 227619-A). MRID 47532

LeBlanc, G.; Sousa, J. (1982) Acute Toxicity of Triadine 10 to Channel Catfish ...: Bionomics 

Report #BW-82-2-1120. (Unpublished study received Jun 11, 1982 under 1258-990; 

prepared by EG & G, Bionomics, submitted by Olin Corp., Stamford, CT; CDL: 247712-

A). MRID 105189

LeBlanc, G.; Sousa, J. (1982) Acute Toxicity of Triadine 10 to Rainbow Trout ...: Report #BW82-2-1117. (Unpublished study received Jun 11, 1982 under 1258-990; prepared by EG 
Docket Number EPA-HQ-OPP-2014-0654

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& G, Bionomics, submitted by Olin Corp., Stamford, CT; CDL:247712-B). MRID 

105190

LeBlanc, G.; Sousa, J. (1982) Acute Toxicity of Triadine 10 to Bluegill ...: Bionomics Report 

#BW-82-2-1119. (Unpublished study received Jun 11, 1982 under 1258-990; prepared by 

EG & G, Bionomics, submitted by Olin Corp., Stamford, CT; CDL:247712-C). MRID 

105191

LeBlanc, G.; Sousa, J. (1982) Acute Toxicity of Milidin X-2 to Rainbow Trout ...: Bionomics 

Report #BW-82-4-1145. (Unpublished study received Nov 8, 1982 under 21167-2; 

prepared by EG & G, Bionomics, submitted by Demille Chemical Corp., Jersey City, NJ; 

CDL:248883-A). MRID 118414

LeBlanc, G.; Sousa, J. (1982) Acute Toxicity of Milidin X-2 to Bluegill ...: Bionomics Report 

#BW-82-4-1144. (Unpublished study received Nov 8, 1982 under 21167-2; prepared by 

EG & G, Bionomics, submitted by Demille Chemical Corp., Jersey City, NJ; 

CDL:248883-B). MRID 118415

LeBlanc, G.; Surprenant, D. (1982) Acute Toxicity of Triadine-10 to the Water Flea ...: 

Bionomics Report #BW-82-2-1122. (Un- published study received Jun 11, 1982 under 

1258-990; prepared by EG & G, Bionomics, submitted by Olin Corp., Stamford, CT; 

CDL:247712-D) MRID 105192

Rausina, G. (1973) Report to Demille Chemical Corporation: Four-Day Static Fish Toxicity 

Studies with Milidin X-2 in Rainbow Trout and Bluegills: IBT No. 665-03509. 

(Unpublished study received May 14, 1974 under 21167-2; prepared by Industrial BioTest Lab- oratories, Inc., submitted by Demille Chemical Corp., Jersey City, N.J.; 

CDL:227625-A). MRID 73588

Ward, S. (1994) Acute Toxicity to the Sheepshead Minnow, Cyprindon variegatus, under FlowThrough Test Conditions: Triazine: Lab Project Number: J9306004G. Unpublished study 

prepared by Toxikon Environmental Sciences. 44 p. MRID 43143102
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Appendix D Screening Level Down-theDrain Analysis

A screening-level Down-the-Drain analysis of HHT was not performed since such an analysis is 

appropriate only for uses of antimicrobial pesticides that would be released solely to domestic 

wastewater treatment facilities. Uses of HHT include industrial uses that would be expected to 

have the potential to release HHT and/or its degradates to industrial wastewater treatment 

facilities and in-service uses that would be expected to have the potential to release HHT and/or 

its degradates to domestic wastewater treatment facilities. Since HHT has the potential to be 

released to both domestic and industrial wastewater treatment facilities, results from a screeninglevel down-the-drain analysis would provide incomplete information on the potential for risks to 

aquatic organisms from exposure to HHT and/or its degradates. 
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Appendix E Product Chemistry

The HHT product chemistry information is summarized in Table E1 (source: MRIDs 47284307, 

47284308, and EPI Suite v4.1).

Table E1 – Product Chemistry of HHT

Guideline Numbers HHT Source

830.1800 Enforcement analytical method HPLC

830.6302 Color Brown to dark brown

830.6303 Physical State TGAI is a solid

830.6304 Odor Aldehyde like

830.6313 Stability Stable for one year

830.6314 Oxidation/Reduction Not applicable

830.6315 Flammability Not applicable

830.6316 Explodability Not applicable

830.7000 pH at25 °C Not applicable

830.7050 UV/Visible Absorption Not applicable

830.7200 Melting point (°C) 155 o C

830.7220 Boiling point (°C) Not applicable

830.7300 Density (g/cm3) 1.2-1.6 g/L

830.7370 Dissociation Constant pKa(s) Not applicable

830.7550 Log Kow

-2.3 (pH 5, 24 C)

-2.0 (pH 7, 24 C); 

1.3 (pH 9, 24 C)

MRID# 47284308

830.7840 Solubility in water (mg/L) at 25 oC 3 g/L (EPI Suite)

830.7860 Solubility in organic solvents Not applicable

830.7950 Vapor pressure (mm Hg) at 25 °C

11.2 mm Hg at 20 C; 

15.15 mm Hg at 25 C; 

61.1 mm Hg at 50 C

MRID 47284307