Docket Number: EPA-HQ-OPP-2009-0725 

www.regulations.gov 

United States Chemical Safety June 2010 

Environmental Protection and Pollution Prevention 

Agency (7510P) 

2-Mercaptobenzothiazole Final Work Plan 

Registration Review 

June 2010 

 

 

Docket Number: EPA-HQ-OPP-2009-0725 

www.regulations.gov 

TABLE OF CONTENTS

2-Mercaptobenzothiazole Registration Review Team................................................... 4 

I. INTRODUCTION..................................................................................................... 5 

II. SUMMARY OF COMMENTS RECEIVED ON PRELIMINARY WORK 

PLAN.......................................................................................................................... 5 

III. RISK ASSESSMENT AND DATA NEEDS........................................................... 6 

IV. TIMELINE.............................................................................................................. 10 

V. GLOSSARY of TERMS & ABBREVIATIONS.................................................. 11 

 
Docket Number: EPA-HQ-OPP-2009-0725 

www.regulations.gov 

2-Mercaptobenzothiazole Registration Review Team

Human Health & Environmental Effects 

William Hazel 

Srinivas Gowda 

Risk Management

Eliza Blair 

Lance Wormell 

Office of General Counsel

Philip Ross 

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Docket Number: EPA-HQ-OPP-2009-0725 

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I. INTRODUCTION

This is the Environmental Protection Agency’s (EPA or “the Agency”) Final 

Work Plan (FWP) for the registration review of 2-Mercaptobenzothiazole (Case 2380). 

The FWP includes the expected registration review timeline. The work plan also 

addresses public comments received concerning the Preliminary Work Plan in the 

Summary Document which was posted in the 2-Mercaptobenzothiazole registration 

review docket, and any other comments concerning the initial docket postings. The 

Summary Document provided information on what EPA knows about the pesticide and 

what additional risk analyses and data or information the Agency believes are needed to 

make a registration review decision. 

The Agency is implementing the Registration Review program pursuant to 

Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and will 

review each registered pesticide every 15 years to determine whether it continues to meet 

the FIFRA standard for registration. Changes in science, public policy and pesticide use 

practices will occur over time. The registration review program is intended to make sure 

that, as the ability to assess risk evolves and as policies and practices change, all 

registered pesticides continue to meet that statutory standard. The public phase of 

registration review begins when the initial docket is opened for each case. Information on 

this program is provided at: http://www.epa.gov/oppsrrd1/registration_review/. 

The 2-Mercaptobenzothiazole Preliminary Work Plan was entered into the docket 

for this registration review on December 16, 2009. The 90-day comment period ended on 

March 16, 2010. The Preliminary Work Plan document is available on 

www.regulations.gov, docket number EPA-HQ-OPP-2009-0725. 

II. SUMMARY OF COMMENTS RECEIVED ON PRELIMINARY WORK 

PLAN

The Agency received one comment from R.T. Vanderbilt, Inc. during the 

comment period on the initial docket as described below. In addition, the Agency 

received one comment from the FIFRA Endangered Species Task Force (FESTF). The 

anticipated data needs, work plan and timeline described in the Preliminary Work Plan 

remain as they were presented initially. This document makes final the work plan for the 

2-Mercaptobenzothiazole registration review process. 

In the Preliminary Work Plan, the Agency solicited comments on three specific 

topics: environmental justice, water body impairment, and trade irritants. No comments 

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

Comment: The FIFRA Endangered Species Task Force (FESTF) submitted a comment 

noting that it has data that will assist the Agency in conducting an endangered species 

risk assessment for 2-Mercaptobenzothiazole, and requesting that any technical registrant 

for 2-Mercaptobenzothiazole who is not a member of the FESTF (or a company having 

met its data compensation obligations) be asked to provide a formal offer-to-pay to 

FESTF for reliance on their data. 

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Docket Number: EPA-HQ-OPP-2009-0725 

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Response: The Agency thanks FESTF for its comment and will consider this information 

as it conducts the registration review and makes its registration review decisions. 

Comment: R.T. Vanderbilt submitted a document responding to the Guidance for 

Commenters section of the 2-Mercaptobenzothiazole Preliminary Work Plan (“2-

Mercaptobenzothiazole Summary Document: Registration Review”, December 2009). 

The document confirmed available information for each section, including application 

information, use sites, and trade irritants. 

Response: The Agency thanks R.T. Vanderbilt for its comment and will use this 

information as it conducts the registration review and makes its registration review 

decisions. 

III. RISK ASSESSMENT AND DATA NEEDS

 2-Mercaptobenzothiazole shares its single product, Vancide 51, with another 

active ingredient, sodium dimethyldithiocarbamate. Vancide 51 contains 2-

Mercaptobenzothiazole at a concentration of 2.4%, and sodium dimethyldithiocarbamate 

at a concentration of 27.6%. In response to the Dimethyldithiocarbamate Salts 

Reregistration Eligibility Decision (RED) in June 2009, the registrant submitted requests 

to voluntarily cancel several uses of Vancide 51. Effective November 12, 2009, upon 

publication of the final cancellation order for this product in the Federal Register, the 

wood veneer, textile fabric, and alginate paste preservation uses were removed from the 

Vancide 51 registration. The remaining registered uses (materials preservation of 

metalworking fluids, paper/paperboard products, and starch/casein pastes and solutions) 

will be assessed in this registration review. 

 A pesticide product containing 2-Mercaptobenzothiazole was first registered in 

1949. A RED was issued for 2-Mercaptobenzothiazole in September 1994. The Agency 

anticipates needing additional data to complete a risk assessment for Registration 

Review. 

Human Health Risk 

 

Toxicity

 

 2-Mercaptobenzothiazole is registered for use as a preservative of metalworking 

fluids, starch/casein pastes and solutions, and paper and paperboard sheet surface 

treatment. In the 1994 RED, dermal risks were well below the Agency’s level of concern 

for occupational handlers. However, a 90-day inhalation toxicity study is needed to 

elucidate potential systemic adverse effects that may result from this route of exposure 

due to aerosolization from metalworking fluids and open-pour addition of preservatives 

in a manufacturing setting. 

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Dietary and Drinking Water Exposure

 All registered use sites for 2-Mercaptobenzothiazole are indoors. Dietary 

exposure via drinking water is possible in the event a discharge of contaminated waste 

water occurs from a facility manufacturing starch or casein suspensions or pastes or from 

metalworking facilities. In such cases, 2-Mercaptobenzothiazole may pass through 

wastewater treatment facilities and into drinking water. The potential for this to occur 

and the extent needs to be assessed and will be based on physicochemical properties and 

environmental fate studies now available or anticipated to be needed in association with 

the subject Registration Review. 

The currently-registered use of the 2.4% SC/L as a surface treatment of paper and 

paperboard sheeting is not expected to result in dietary exposure because the label 

prohibits use for food packaging purposes. 

Occupational and Residential Exposure

 

2-Mercaptobenzothiazole is registered for use as a preservative of metalworking 

fluids, starch/casein pastes and solutions, and paper and paperboard sheet surface 

treatment. An occupational handler risk assessment was conducted in 1994 for the 2-

Mercaptobenzothiazole RED. Application methods such as open pouring of the liquid 

concentrate and open pouring of the powder into adhesives, paints, and other industrial 

products present the potential for dermal and inhalation exposure to applicators. While a 

dermal toxicity study was performed for the RED, and inhalation toxicity study has not 

been performed. A 90-day inhalation toxicity study is anticipated as being needed to 

elucidate potential systemic adverse effects that may result from the inhalation 

occupational route of exposure due to aerosolization from metalworking fluids and openpour addition of preservatives in a manufacturing setting. 

 It is also anticipated that exposure studies to measure inhalation and dermal 

exposures to occupational handlers will be required that address: (i) metalworkers using 

treated metalworking fluids; (ii) open-pouring into starch and casein pastes and solutions 

in the factory; and (iii) paper and paperboard sheet surface treatment. Each of these 

scenarios will need to be assessed to estimate the concomitant risks to workers.

Anticipated Human Health Data Needs 

Human Health Toxicity:

o (GLN 870.3465) 90-Day Inhalation Toxicity (Rat) 

Occupational and Residential Exposure:

o ((GLN 875.2700) Product Use Information – Indoor 

o (GLN 875.2800) Descriptions of Human Activity 

o (GLN 875.1200) Indoor Dermal Exposure 

o (GLN 875.1400) Indoor Inhalation Exposure 

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o (GLN 875.1600) Applicator Exposure Monitoring Data Reporting for 

Dermal and Inhalation Data 

o (GLN 875.2900) Data Reporting and Calculations 

Further information is available in “Summary of Human Health Effects Data for 

the 2-Mercaptobenzothiazole Registration Review Decision Document,” dated December 

7, 2009. 

Anticipated Physical/ Chemical Property Data Needs 

 All product chemistry data requirements have been fulfilled for the active 

ingredient 2-Mercaptobenzothiazole. Therefore, the Agency does not anticipate needing 

additional product chemistry data at this time. 

Further information is available in “Summary of Product Chemistry, 

Environmental Fate, and Ecotoxicity Data for the 2-Mercaptobenzothiazole Registration 

Review Summary Document”, dated December 7, 2009. 

Environmental Fate 

No studies have been submitted regarding the environmental fate of 2-

mercaptobenzothiazole, and none have been reviewed. The Agency has not conducted an 

environmental fate assessment for 2-mercaptobenzothiazole use patterns described in this 

document. The Agency needs to conduct an environmental fate assessment for material 

preservatives that potentially pass through waste water treatment plants (WWTPs) and 

may be discharged into terrestrial and aquatic environments. For this assessment, the 

Agency anticipates needing those data outlined below. 

Ecological Risk 

No risk assessment was performed for 2-mercaptobenzothiazole. The Agency has 

since reviewed four ecotoxicology studies for 2-mercaptobenzothiazole. The four studies 

submitted on the 98.22 - 100% active ingredient were all found to be acceptable for use 

in a hazard assessment. An ecological assessment will be needed for materials 

preservatives uses and paper mill discharges that potentially pass through waste water 

treatment plants (WWTPs) and may be discharged into terrestrial and aquatic 

environments. One additional ecotoxicity study is needed to conduct this assessment. 

Anticipated Environmental Fate and Ecological Data Needs for 2-

mercaptobenzothiazole 

The Agency anticipates needing the following data in order to conduct a complete 

environmental fate and ecotoxicity assessment, including an endangered species 

assessment for all uses: 

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Environmental Fate Risk Assessment Data Needs: 

o (GLN 835.2120) Hydrolysis 

o (GLN 835.2240) Photodegradation in Water 

o (GLN 850.6800) Modified Activated Sludge Respiration Inhibition 

o (GLN 835.1110) Activated Sludge Sorption Isotherm 

o (GLN 835.3110) Ready Biodegradability 

Ecological Risk Assessment Data Needs: 

o (GLN 850.5400) Algal Toxicity (Tier II) using freshwater green alga, 

Selenastrum capricornutum. 

Further information is available in “Summary of Product Chemistry, 

Environmental Fate, and Ecotoxicity Data for the 2-Mercaptobenzothiazole Registration 

Review Summary Document”, dated December 7, 2009. 

Endocrine Disruptor Screening Program 

As required under FFDCA section 408(p), EPA has developed the Endocrine 

Disruptor Screening Program (EDSP) to determine whether certain substances (including 

pesticide active and other ingredients) may have an effect in humans or wildlife similar to 

an effect produced by a “naturally occurring estrogen, or other such endocrine effects as 

the Administrator may designate.” The EDSP employs a two-tiered approach to making 

the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays 

to identify the potential of a chemical substance to interact with the estrogen, androgen, 

or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening 

and are found to have the potential to interact with E, A, or T hormonal systems will 

proceed to the next stage of the EDSP where EPA will determine which, if any, of the 

Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to 

identify any adverse endocrine related effects caused by the substance, and establish a 

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

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. This list of chemicals was selected based on the potential for human 

exposure through pathways such as food and water, residential activity, and certain postapplication agricultural scenarios. This list should not be construed as a list of known or 

likely endocrine disruptors. 

2-Mercaptobenzothiazole is not among the group of 58 pesticide active 

ingredients on the initial list to be screened under the EDSP. Under FFDCA sec. 408(p) 

the Agency must screen all pesticide chemicals. Accordingly, EPA anticipates issuing 

future EDSP test orders/data call-ins for all pesticide active ingredients. 

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For further information on the status of the EDSP, the policies and procedures, the 

list of 67 chemicals, the test guidelines and the Tier 1 screening battery, please visit our 

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

IV. TIMELINE

EPA has created the following estimated timeline for the completion of the 2-

Mercaptobenzothiazole registration review. 

Registration Review for 2-Mercaptobenzothiazole 

Projected Registration Review Timeline

Activities Time 

Opening Docket 

Open Docket Completed December 2009 

Close Public Comment Period Completed March 2010 

Case Development 

Final Work Plan Completed June 2010 

Issue DCI June 2011 

Data Submission June 2012 

Preliminary Risk Assessment June 2014 

Close Public Comment Period September 2014 

Registration Review Decision 

Proposed Registration Review Decision December 2014 

Public Comment Period March 2015 

Final Registration Review Decision & 

Begin Post-Decision Follow-up 2015 

Total (years) 5 

Next Steps:

A Data Call-In (DCI) will be developed regarding the data gaps listed under the 

“Risk Assessment and Data Needs” section. Also, human health and ecological risk 

assessments will be conducted for all uses. 

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V. GLOSSARY of TERMS & ABBREVIATIONS

ai Active Ingredient 

AR Anticipated Residue 

ASTM American Society for Testing and Materials 

AWPA American Wood Preserver’s Association 

CFR Code of Federal Regulations 

cPAD Chronic Population Adjusted Dose 

CSF Confidential Statement of Formula 

CSFII USDA Continuing Surveys for Food Intake by Individuals 

DCI Data Call-In 

DEEM Dietary Exposure Evaluation Model 

DFR Dislodgeable Foliar Residue 

DNT Developmental Neurotoxicity 

DWLOC Drinking Water Level of Comparison 

EC Emulsifiable Concentrate Formulation 

EDWC Estimated Drinking Water Concentration 

EEC Estimated Environmental Concentration 

EPA Environmental Protection Agency 

EUP End-Use Product 

FDA Food and Drug Administration 

FIFRA Federal Insecticide, Fungicide, and Rodenticide Act 

FFDCA Federal Food, Drug, and Cosmetic Act 

FQPA Food Quality Protection Act 

FOB Functional Observation Battery 

GENEEC Tier I Surface Water Computer Model 

IR Index Reservoir 

LC50 Median Lethal Concentration. A statistically derived concentration of a 

substance that can be expected to cause death in 50% of test animals. It is 

usually expressed as the weight of substance per weight or volume of water, air 

or feed, e.g., mg/l, mg/kg or ppm. 

LD50 Median Lethal Dose. A statistically derived single dose that can be expected to 

cause death in 50% of the test animals when administered by the route indicated 

(oral, dermal, inhalation). It is expressed as a weight of substance per unit 

weight of animal, e.g., mg/kg. 

LOC Level of Concern 

LOAEL Lowest Observed Adverse Effect Level 

μg/g Micrograms Per Gram 

μg/L Micrograms Per Liter 

mg/kg/day Milligram Per Kilogram Per Day 

mg/L Milligrams Per Liter 

MOE Margin of Exposure 

MRID Master Record Identification (number). EPA's system of recording and tracking 

submitted studies. 

MUP Manufacturing-Use Product 

NA Not Applicable 

NAWQA USGS National Ambient Water Quality Assessment 

NPDES National Pollutant Discharge Elimination System 

NR Not Required 

NOAEL No Observed Adverse Effect Level 

OPP EPA Office of Pesticide Programs 

OPPTS EPA Office of Prevention, Pesticides and Toxic Substances 

PAD Population Adjusted Dose 

PAIRA Pure Active Ingredient Radiolabelled 

PCA Percent Crop Area 

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PDP USDA Pesticide Data Program 

PHED Pesticide Handler's Exposure Data 

PHI Preharvest Interval 

ppb Parts Per Billion 

PPE Personal Protective Equipment 

ppm Parts Per Million 

PRZM/EXAMS Tier II Surface Water Computer Model 

Q1* The Carcinogenic Potential of a Compound, Quantified by the EPA's Cancer 

Risk Model 

RAC Raw Agriculture Commodity 

RASSB Risk Assessment and Science Support Branch 

RED Reregistration Eligibility Decision 

REI Restricted Entry Interval 

RfD Reference Dose 

RQ Risk Quotient 

SCI-GROW Tier I Ground Water Computer Model 

SAP Science Advisory Panel 

SF Safety Factor 

SLN Special Local Need (Registrations Under Section 24©) of FIFRA) 

TGAI Technical Grade Active Ingredient 

TEP Typical End-Use Product 

USDA United States Department of Agriculture 

UF Uncertainty Factor 

WPS Worker Protection Standard