US Environmental Protection Agency 

Office of Pesticide Programs 

Reregistration Eligibility Decision 

for Terbufos 

When EPA concluded the organophosphate (OP) cumulative risk assessment in July 2006, all 

tolerance reassessment and reregistration eligibility decisions for individual OP pesticides were 

considered complete. OP Interim Reregistration Eligibility Decisions (IREDs), therefore, are 

considered completed REDs. OP tolerance reassessment decisions (TREDs) also are considered 

completed. 

Combined PDF document consists of the following: 

•	 Finalization of Interim Reregistration Eligibility Decisions (IREDs) and Interim Tolerance 

Reassessment and Risk Management Decisions (TREDs) for the Organophosphate Pesticides, and 

Completion of the Tolerance Reassessment and Reregistration Eligibility Process for the 

Organophosphate Pesticides (July 31, 2006) 

•	 Terbufos IRED 
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF 

PREVENTION, PESTICIDES AND TOXIC

SUBSTANCES 

MEMORANDUM

DATE: July 31, 2006 

SUBJECT: Finalization of Interim Reregistration Eligibility Decisions (IREDs) and Interim 

Tolerance Reassessment and Risk Management Decisions (TREDs) for the 

Organophosphate Pesticides, and Completion of the Tolerance Reassessment and 

Reregistration Eligibility Process for the Organophosphate Pesticides 

FROM: Debra Edwards, Director 

Special Review and Reregistration Division 

Office of Pesticide Programs 

TO: Jim Jones, Director 

Office of Pesticide Programs 

As you know, EPA has completed its assessment of the cumulative risks from the 

organophosphate (OP) class of pesticides as required by the Food Quality Protection Act of 

1996. In addition, the individual OPs have also been subject to review through the individualchemical review process. The Agency’s review of individual OPs has resulted in the issuance of 

Interim Reregistration Eligibility Decisions (IREDs) for 22 OPs, interim Tolerance 

Reassessment and Risk Management Decisions (TREDs) for 8 OPs, and a Reregistration 

Eligibility Decision (RED) for one OP, malathion.1 These 31 OPs are listed in Appendix A. 

EPA has concluded, after completing its assessment of the cumulative risks associated 

with exposures to all of the OPs, that: 

(1) the pesticides covered by the IREDs that were pending the results of the OP 

cumulative assessment (listed in Attachment A) are indeed eligible for reregistration; and 

1 Malathion is included in the OP cumulative assessment. However, the Agency has issued a RED for malathion, 

rather than an IRED, because the decision was signed on the same day as the completion of the OP cumulative 

assessment. 

Page 1 of 3 
(2) the pesticide tolerances covered by the IREDs and TREDs that were pending the 

results of the OP cumulative assessment (listed in Attachment A) meet the safety standard under 

Section 408(b)(2) of the FFDCA. 

Thus, with regard to the OPs, EPA has fulfilled its obligations as to FFDCA tolerance 

reassessment and FIFRA reregistration, other than product-specific reregistration. 

The Special Review and Reregistration Division will be issuing data call-in notices for 

confirmatory data on two OPs, methidathion and phorate, for the reasons described in detail in 

the OP cumulative assessment. The specific studies that will be required are: 

− 28-day repeated-dose toxicity study with methidathion oxon; and 

− Drinking water monitoring study for phorate, phorate sulfoxide, and phorate sulfone 

in both source water (at the intake) and treated water for five community water 

systems in Palm Beach County, Florida and two near Lake Okechobee, Florida. 

The cumulative risk assessment and supporting documents are available on the Agency’s website 

at www.epa.gov/pesticides/cumulative and in the docket (EPA-HQ-OPP-2006-0618). 

Page 2 of 3 
Attachment A: 

Organophosphates included in the OP Cumulative Assessment 

Chemical Decision Document Status 

Acephate IRED IRED completed 9/2001 

Azinphos-methyl (AZM) IRED IRED completed 10/2001 

Bensulide IRED IRED completed 9/2000 

Cadusafos TRED TRED completed 9/2000 

Chlorethoxyphos TRED TRED completed 9/2000 

Chlorpyrifos IRED IRED completed 9/2001 

Coumaphos TRED TRED completed 2/2000 

DDVP (Dichlorvos) IRED IRED completed 6/2006 

Diazinon IRED IRED completed 7/2002 

Dicrotophos IRED IRED completed 4/2002 

Dimethoate IRED IRED completed 6/2006 

Disulfoton IRED IRED completed 3/2002 

Ethoprop IRED IRED completed 9/2001 

IRED addendum completed 2/2006 

Fenitrothion TRED TRED completed 10/2000 

Malathion RED RED completed 8/2006 

Methamidophos IRED IRED completed 4/2002 

Methidathion IRED IRED completed 4/2002 

Methyl Parathion IRED IRED completed 5/2003 

Naled IRED IRED completed 1/2002 

Oxydemeton-methyl IRED IRED completed 8/2002 

Phorate IRED IRED completed 3/2001 

Phosalone TRED TRED completed 1/2001 

Phosmet IRED IRED completed 10/2001 

Phostebupirim TRED TRED completed 12/2000 

Pirimiphos-methyl IRED IRED completed 6/2001 

Profenofos IRED IRED completed 9/2000 

Propetamphos IRED IRED completed 12/2000 

Terbufos IRED IRED completed 9/2001 

Tetrachlorvinphos TRED TRED completed 12/2002 

Tribufos IRED IRED completed 12/2000 

Trichlorfon TRED TRED completed 9/2001 

Page 3 of 3 
September 28, 2001 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF 

PREVENTION, PESTICIDES 

AND TOXIC SUBSTANCES 

CERTIFIED MAIL 

Dear Registrant: 

This is to inform you that the Environmental Protection Agency (hereafter referred to as 

EPA or the Agency) has completed its review of the available data and public comments 

received related to the preliminary and revised risk assessments for the organophosphate 

pesticide terbufos. The public comment period on the revised risk assessment phase of the 

reregistration process is closed. Based on comments received during the public comment period 

and additional data received from the registrant, the Agency revised the human health and 

environmental effects risk assessments and made them available to the public on September 14, 

1999. Additionally, the Agency held a Technical Briefing on September 2, 1999, where the 

results of the revised human health and environmental effects risk assessments were presented to 

the general public. This Technical Briefing concluded Phase 4 of the OP Public Participation 

Pilot Process developed by the Tolerance Reassessment Advisory Committee (TRAC), and 

initiated Phase 5 of that process. During Phase 5, all interested parties were invited to participate 

and provide comments and suggestions on ways the Agency might mitigate any estimated risks 

presented in the revised risk assessments. This public participation and comment period 

commenced on September 14, 1999, and closed on November 12, 1999. 

Based on its review, EPA has identified risk management measures that it believes are 

necessary to address the human health and environmental risks associated with the current use of 

terbufos. The EPA is now publishing its interim decision on the reregistration eligibility of and 

risk management decision for the current uses of terbufos and its associated human health and 

environmental risks. The reregistration eligibility and tolerance reassessment decisions for 

terbufos will be finalized once the cumulative risks for all of the organophosphate pesticides are 

considered. The enclosed “Interim Reregistration Eligibility Decision for Terbufos,” which was 

approved on September 28, 2001, contains the Agency’s decision on the individual chemical 

terbufos. 

A Notice of Availability for this Interim Reregistration Eligibility Decision for terbufos is 

being published in the Federal Register. To obtain a copy of the interim RED document, please 

contact the OPP Public Regulatory Docket (7502C), US EPA, Ariel Rios Building, 1200 

Pennsylvania Avenue NW, Washington, DC 20460, telephone (703) 305-5805. Electronic 

copies of the interim RED and all supporting documents are available on the Internet. See 

http:www.epa.gov/pesticides/op. 
The Interim RED is based on the updated technical information found in the terbufos 

public docket. The docket not only includes background information and comments on the 

Agency’s preliminary risk assessments, it also now includes the Agency’s revised risk 

assessment for terbufos (revised as of September 14, 1999), and a document summarizing the 

Agency’s Response to Comments dated August 30, 1999. The Response to Comments 

document describes new studies submitted by the chemical registrant that were used to revise the 

risk assessments, and responds to comments submitted by the registrant, general public, and 

other stakeholders. The docket also includes comments on the revised risk assessment, and any 

risk mitigation proposals submitted during Phase 5. For terbufos, a risk mitigation proposal was 

submitted by the chemical registrant, BASF Corporation (formerly American Cyanamid). 

This document and the process used to develop it are the result of a pilot process to 

facilitate greater public involvement and participation in the reregistration and/or tolerance 

reassessment decisions for these pesticides. As part of the Agency’s effort to involve the public 

in the implementation of the Food Quality Protection Act of 1996 (FQPA), the Agency is 

undertaking a special effort to maintain open public dockets on the organophosphate pesticides 

and to engage the public in the reregistration and tolerance reassessment processes for these 

chemicals. This open process follows the guidance developed by the Tolerance Reassessment 

Advisory Committee (TRAC), a large multi-stakeholder advisory body that advised the Agency 

on implementing the new provisions of the FQPA. The reregistration and tolerance reassessment 

reviews for the organophosphate pesticides are following this new process. 

Please note that the terbufos risk assessment and the attached interim RED concern only 

this particular organophosphate. This interim RED presents the Agency’s reregistration decision 

except for the decision on tolerance reassessment. This interim RED presents the Agency’s 

conclusions on the dietary risks posed by exposure to terbufos alone. The Agency has also 

concluded its assessment of the ecological and worker risks associated with the use of terbufos. 

Because the FQPA directs the Agency to consider available information on the basis of 

cumulative risk from substances sharing a common mechanism of toxicity, such as the toxicity 

expressed by the organophosphates through a common biochemical interaction with the 

cholinesterase enzyme, the Agency will evaluate the cumulative risk posed by the entire 

organophosphate class of chemicals after considering the risks for the individual 

organophosphates. The Agency is working towards completion of a methodology to assess 

cumulative risk and the individual risk assessments for each organophosphate are likely to be 

necessary elements of any cumulative assessment. The Agency has decided to move forward 

with individual assessments and to identify mitigation and risk management measures necessary 

to address those human health and environmental risks associated with the current uses of 

terbufos. The Agency will issue the final tolerance reassessment decision for terbufos and 

finalize decisions on reregistration eligibility once the cumulative risks for all of the 

organophophates are considered. 

This document contains a generic and/or a product-specific Data Call-In(s) (DCI) that 

outline(s) further data requirements for this chemical. Note that a complete DCI, with all 

pertinent instructions, is being sent to registrants under separate cover. Additionally, for 

product-specific DCIs, the first set of required responses to is due 90 days from the receipt of the 

DCI letter. The second set of required responses is due eight months from the date of the DCI. 
In this interim RED, the Agency has determined that terbufos will be eligible for 

reregistration provided that all the conditions identified in this document are satisfied, including 

implementation of the risk management measures outlined in Section IV of the document. The 

Agency believes that current uses of terbufos may pose unreasonable adverse effects to human 

health and the environment, and that such effects can be adequately managed with the risk 

management measures identified in this interim RED. Accordingly, the Agency recommends 

that registrants implement these risk management measures immediately. Sections IV and V of 

this interim RED describe labeling amendments for end-use products and data requirements 

necessary to implement these mitigation and risk reduction measures. Instructions for registrants 

on submitting the revised labeling can be found in the set of instructions for product-specific 

data that accompanies this interim RED. 

Should a registrant fail to implement any of the risk management measures outlined in this 

document, the Agency will continue to have concerns about the risks posed by terbufos. Where 

the Agency has identified any unreasonable adverse effect to human health and the environment, 

the Agency may at any time initiate appropriate regulatory action to address this concern. At 

that time, any affected person(s) may challenge the Agency’s action. 

If you have questions on this document or the label changes necessary for reregistration, 

please contact the Special Review and Reregistration Division’s Chemical Review Manager, 

Eric R. Olson at (703) 308-8067. For questions about product reregistration and/or the Product 

DCI that accompanies this document, please contact Karen Jones (703) 308-8047. 

Sincerely 

Lois A. Rossi, Director 

Special Review and 

Reregistration Division 

Attachment 
Interim Reregistration Eligibility Decision
 

for
 

TERBUFOS
 

Case No. 0109
 
TABLE OF CONTENTS 

Executive Summary ........................................................... 1 
 

I. Introduction ............................................................ 5 
 

II. Chemical 	
 Overview ...................................................... 7 
 

A. Regulatory History .................................................. 7 
 

B. Chemical Identification .............................................. 7 
 

C. Use Profile ......................................................... 8 
 

D. Estimated Usage of Pesticide .......................................... 9 
 

III.	 Summary of Terbufos Risk Assessments .................................... 10
 

A. Human Health Risk Assessment ...................................... 10
 

1. Dietary Risk from Food ........................................ 10
 

a. Toxicity ................................................ 11
 

b. FQPA Safety Factor ...................................... 11
 

c. Population Adjusted Dose (PAD) ........................... 12
 

d. Exposure Assumptions .................................... 12
 

e. Food Risk Characterization ................................ 13
 

2. Dietary Risk from Drinking Water .............................. 13
 

a. Surface Water ........................................... 14
 

b. Ground Water ........................................... 15
 

c. Drinking Water Levels of Comparison (DWLOCs) ............ 15
 

3. Aggregate Risk ............................................... 17
 

4. Occupational and Residential Risk ............................... 18
 

a. Toxicity ................................................ 18
 

b. Exposure ............................................... 20
 

c. Occupational Handler Risk Summary ....................... 22
 

1) Agricultural Handler Risk ....................... 22
 

2) Post-Application Occupational Risk ............... 26
 

B. Environmental Risk Assessment ...................................... 26
 

1. Environmental Fate and Transport .............................. 27
 

a. Degradation and Mobility ................................. 27
 

b. Field Dissipation ......................................... 28
 

2. Risk to Birds and Mammals .................................... 28
 

3. Risk to Aquatic Species ........................................ 29
 

a. Aquatic LOC Assessment ................................. 29
 

b. Aquatic Incidents ........................................ 29
 

4. Endangered Species ........................................... 31
 

IV. 	 Interim Risk Management and Reregistration Decision ....................... 31
 

A. Determination of Interim Reregistration Eligibility ...................... 31
 

B. Summary of Phase 5 Comments and Responses ......................... 33
 

C. Regulatory Position ................................................ 34
 

1. FQPA Assessment ............................................. 34
 

a. “Risk Cup” Determination ................................ 34
 

b. Tolerance Summary ...................................... 35
 
2. Endocrine Disruptor Effects .................................... 38
 

3. Labels ....................................................... 38
 

a. Agricultural Use Exposure Reduction Measures .............. 38
 

b. Homeowner Use Exposure Reduction Measures ............... 39
 

D. Regulatory Rationale ............................................... 39
 

1. Human Health Risk Mitigation .................................. 39
 

a. Dietary Mitigation ....................................... 39
 

1) Acute Dietary (Food) ........................... 39
 

2) Chronic Dietary (Food) ......................... 40
 

3) Drinking Water ................................ 40
 

b. Occupational Risk Mitigation .............................. 41
 

1) Agricultural Uses .............................. 41
 

2) Post-Application Risk ........................... 43
 

c. Homeowner Risk Mitigation ............................... 43
 

2. Environmental Risk Mitigation ................................. 44
 

3. Benefits Assessment ........................................... 44
 

E. Other Labeling .................................................... 45
 

1. Endangered Species Statement .................................. 45
 

V.	 What Registrants Needs to Do ............................................ 46
 

A. Manufacturing Use Products ........................................ 48
 

1. Additional Generic Data Requirements ........................... 48
 

2. Labeling Requirements for Manufacturing Use Products ............ 48
 

B. End-Use Products .................................................. 48
 

1. Additional Generic Data Requirements ........................... 48
 

2. Labeling Requirements for End-Use Products ..................... 49
 

C. Existing Stocks .................................................... 49
 

D. Required Labeling Changes Summary Table ........................... 50
 

VI. Related Documents and How to Access Them ............................... 61
 

VI. APPENDICES ......................................................... 62
 

Appendix A. TABLE OF USE PATTERNS ELIGIBLE FOR
 

Appendix B. TABLE OF GENERIC DATA REQUIREMENTS AND STUDIES
 

Appendix D. CITATIONS CONSIDERED TO BE PART OF THE DATA BASE
 

SUPPORTING THE INTERIM REREGISTRATION DECISION 

Appendix G. EPA’S BATCHING OF TERBUFOS PRODUCTS FOR MEETING
 

ACUTE TOXICITY DATA REQUIREMENTS FOR 

REREGISTRATION ..................................... 63
 

USED TO MAKE THE REREGISTRATION DECISION ...... 68
 

Appendix C. TECHNICAL SUPPORT DOCUMENTS .................... 78
 

(BIBLIOGRAPHY) ...................................... 80
 

Appendix E. GENERIC DATA CALL-IN .............................. 104
 

Appendix F. PRODUCT SPECIFIC DATA CALL-IN .................... 105
 

REREGISTRATION .................................... 106
 

Appendix H. LIST OF REGISTRANTS SENT THIS DATA CALL-IN ...... 108
 

Appendix I. LIST OF AVAILABLE RELATED DOCUMENTS AND

ELECTRONICALLY AVAILABLE FORMS ............... 109
 

TERBUFOS TEAM 

Health Effects Risk Assessment
 

Jeffery Dawson
 

William Hazel
 

Michael Metzger
 

Christina Swartz
 

Environmental Fate (Drinking Water and Ecological) Risk Assessment
 

Thomas Bailey
 

James Breithaupt
 

James Carleton
 

David Farrar
 

Use and Usage Analysis
 

Donald Atwood
 

David Brassard
 

Registration Support 

Marilyn Mautz 

Risk Management
 

Pam Noyes
 

Eric R. Olson
 

Mark Hartman
 
GLOSSARY OF TERMS AND ABBREVIATIONS 

AE Acid Equivalent 

a.i. Active Ingredient 

AGDCI Agricultural Data Call-In 

ai Active Ingredient 

aPAD Acute Population Adjusted Dose 

AR Anticipated Residue 

ARC Anticipated Residue Contribution 

BCF Bioconcentration Factor 

CAS	 Chemical Abstracts Service 

CI Cation 

CNS Central Nervous System 

cPAD Chronic Population Adjusted Dose 

CSF Confidential Statement of Formula 

CFR Code of Federal Regulations 

CSFII USDA Continuing Surveys for Food Intake by Individuals 

DCI Data Call-In 

DEEM Dietary Exposure Evaluation Model 

DFR Dislodgeable Foliar Residue 

DRES Dietary Risk Evaluation System 

DWEL	 Drinking Water Equivalent Level (DWEL) The DWEL represents a medium 

specific (i.e., drinking water) lifetime exposure at which adverse, noncarcinogenic 

health effects are not anticipated to occur. 

DWLOC Drinking Water Level of Comparison. 

EC Emulsifiable Concentrate Formulation 

EEC	 Estimated Environmental Concentration. The estimated pesticide concentration 

in an environment, such as a terrestrial ecosystem. 

EP End-Use Product 

EPA U.S. Environmental Protection Agency 

FAO Food and Agriculture Organization 

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 

G Granular Formulation 

GENEEC Tier I Surface Water Computer Model 

GLC Gas Liquid Chromatography 

GLN Guideline Number 

GM Geometric Mean 

GRAS Generally Recognized as Safe as Designated by FDA 

HA	 Health Advisory (HA). The HA values are used as informal guidance to 

municipalities and other organizations when emergency spills or contamination 

situations occur. 

HAFT Highest Average Field Trial 

HDT Highest Dose Tested 

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. 

LEL Lowest Effect Level
 

LOC Level of Concern
 

LOD Limit of Detection 
 

LOAEL Lowest Observed Adverse Effect Level
 

MATC Maximum Acceptable Toxicant Concentration
 

MCLG Maximum Contaminant Level Goal (MCLG) The MCLG is used by the Agency
 

to regulate contaminants in drinking water under the Safe Drinking Water Act. 

mg/kg/day Milligram Per Kilogram Per Day 

mg/L Milligrams Per Liter 

MOE Margin of Exposure 

MP Manufacturing-Use Product 

MPI Maximum Permissible Intake 

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

studies submitted. 

NA Not Applicable 

N/A Not Applicable 

NAWQA USGS National Water Quality Assessment 

NOEC No Observable Effect Concentration 

NOEL No Observed Effect Level 

NOAEL No Observed Adverse Effect Level 

NPDES National Pollutant Discharge Elimination System 

NR Not Required 

OP Organophosphate 

OPP EPA Office of Pesticide Programs 

OPPTS EPA Office of Prevention, Pesticides and Toxic Substances 

Pa pascal, the pressure exerted by a force of one newton acting on an area of one 

square meter. 

PAD Population Adjusted Dose 

PADI Provisional Acceptable Daily Intake 

PAG Pesticide Assessment Guideline 

PAM Pesticide Analytical Method 

PCA Percent Crop Area 

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 

PRN Pesticide Registration Notice 

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 

RBC Red Blood Cell 

RED Reregistration Eligibility Decision 

REI Restricted Entry Interval 

RfD Reference Dose 

RQ Risk Quotient 

RS Registration Standard 

RUP Restricted Use Pesticide 

SAP Science Advisory Panel 

SCI-GROW Tier I Ground Water Computer Model 

SF Safety Factor 

SLC Single Layer Clothing 

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

TC	 Toxic Concentration. The concentration at which a substance produces a toxic 

effect. 

TD Toxic Dose. The dose at which a substance produces a toxic effect. 

TEP Typical End-Use Product 

TGAI Technical Grade Active Ingredient 

TLC Thin Layer Chromatography 

TMRC Theoretical Maximum Residue Contribution 

torr	 A unit of pressure needed to support a column of mercury 1 mm high under 

standard conditions. 

TRR Total Radioactive Residue 

UF Uncertainty Factor 

Fg/g Micrograms Per Gram 

Fg/L Micrograms Per Liter 

USDA United States Department of Agriculture 

USGS United States Geological Survey 

UV Ultraviolet 

WHO World Health Organization 

WP Wettable Powder 

WPS Worker Protection Standard 
Executive Summary 

EPA has completed its review of public comments on the revised risk assessments and is 

issuing its interim risk management decisions for terbufos. The decisions outlined in this 

document do not include the final tolerance reassessment decision for terbufos. At this time, no 

tolerance actions are necessary for terbufos. The final tolerance reassessment decision for this 

chemical will be issued once the cumulative risks for all of the organophosphates are considered. 

The Agency may need to pursue further risk management measures for terbufos once cumulative 

risks are considered. 

The revised risk assessments are based on review of the required target data base 

supporting the use patterns of currently registered products and new information received. The 

Agency invited stakeholders to provide proposals, ideas or suggestions on appropriate mitigation 

measures before the Agency issued its risk mitigation decision on terbufos. After considering 

the revised risks, as well as mitigation proposed by BASF the technical registrant of terbufos, 

and comments and mitigation suggestions from other interested parties, including the states of 

North Carolina and Indiana, Defenders of Wildlife, several property owners, growers and grower 

organizations, and agricultural extension agents, EPA developed its risk management decision 

for uses of terbufos that pose risks of concern. This decision is discussed fully in this document. 

Terbufos is an organophosphate insecticide-nematicide used to control a variety of insect 

pests, first registered in 1974 to control insect pests on corn, sugar beets, and sorghum. Use data 

from 1987 to 1996 indicate an average domestic use of approximately 7.5 million pounds of 

active ingredient per year during that period. 

Overall Risk Summary 

EPA’s human health risk assessment for terbufos indicates some risk concerns. Food risk, 

both acute and chronic, is below the Agency’s level of concern. Drinking water risk estimates 

based on models, from both ground and surface water for acute and chronic exposures, is of 

concern for most populations, notably infants and children. Even when potential food exposures 

to terbufos are not considered, modeled concentrations of terbufos in groundwater and surface 

water alone exceed the Agency’s level of acute and chronic dietary risk concern based on 

Estimated Environmental Concentrations (EEC’s). The Agency also has some risk concerns for 

handlers who handle terbufos in open bag/open cab and closed systems (i.e., Lock-N-Load 

system and enclosed cabs). Terbufos is not registered for use in residential settings, and so the 

Agency expects no residential/homeowner exposures. 

EPA’s environmental risk assessment for terbufos indicates risk concerns to non-target 

organisms. The Agency is particularly concerned about risks to aquatic species, based on the 

Agency’s aquatic assessment, and supported by fish kill incidents associated with the use of 

terbufos on corn. 

To manage risks of concern posed by the uses of terbufos, EPA considered the risk 

1
 
management proposal submitted by the technical registrant, as well as comments and ideas from 

other interested parties, and has decided on a number of label amendments to address the 

ecological, drinking water, and worker risk concerns. Results of the risk assessments, and 

required label amendments to manage those risks, are presented in this interim RED. 

Dietary Risk 

Acute and chronic dietary risk for food alone do not exceed the Agency’s level of 

concern. However, acute and chronic dietary risks are a concern when potential modeled 

drinking water exposures are added to the acute and chronic dietary risk assessment. Drinking 

water risks of concern are expected to be managed by the steps outlined in the discussion of 

ecological risk explained below. 

Occupational Risk 

Occupational exposures to terbufos are not a risk concern for most handler scenarios. 

However, the Agency does have risk concerns for handlers loading and applying the Counter 

15G Lock-N-Load product and Counter 20CR open bag product. The Agency has determined 

that risk concerns for Counter 15G can be mitigated to acceptable levels if applications are 

restricted to closed cab tractors and the maximum application rate on sorghum is reduced. For 

the Counter 20CR open bag product, risk concerns on sorghum can also be mitigated to an 

acceptable level if there is a reduction in the maximum application rate. The Agency also has 

risk concerns for workers using the Counter 20CR product in open bags under a Special Local 

Need (SLN) registration in North Carolina which allows use on corn at twice the maximum 

application rate of the Section 3 registration. The Agency has determined that this risk concern 

can be mitigated to an acceptable level if North Carolina revises the SLN registration to permit 

use of Counter 20CR in closed loading systems only (i.e., “Lock-N-Load” packaging). 

EPA does not believe there is a significant potential for post-application exposures to 

terbufos based on application methods, timing, and frequency. The Agency concludes that the 

48 hour Restricted Entry Interval (REI) established under EPA’s Worker Protection Standards 

(WPS) is sufficient to protect workers who may re-enter treated areas. Therefore, with the 

addition of the label restrictions and amendments detailed in this document, the Agency has 

determined that, until the outcome of the cumulative risk assessment for all of the 

organophosphates has been decided, all currently registered uses of terbufos may continue. 

Ecological Risk 

Ecological risks to terrestrial and aquatic organisms are of concern to the Agency. The 

Agency is concerned about potential adverse effects to terrestrial and aquatic organisms, based 

on the Agency’s assessment and fish kills associated with the use of terbufos on corn. Aquatic 

incidents reported to EPA indicate that terbufos is the leading cause of fish kills among 

pesticides applied to corn, and is fourth in causing fish kills for any pesticide applied to any crop. 

2
 
The Agency has determined that these risks can be reduced by implementing limitations 

on sales of terbufos and adding buffers to the labels. The registrant has agreed to a phased 

approach that will ultimately reduce sales of terbufos by 55% by 2008 based on 2000 sales 

figures. By reducing the total amount of terbufos available to be applied, the Agency expects 

that risks to aquatic and terrestrial organisms will be reduced. 

The buffers to be implemented are; 1) a 500 ft. vegetative buffer between treated area and 

surface water on neighboring land, 2) a 500 ft. vegetative buffer between a standpipe drain outlet 

and surface water on neighboring land, 3) a 66 ft. setback between the treated area and entry 

points to surface water bodies on non-highly erodible soils and 300 ft. on highly erodible soils, 

4) a 66 ft. setback between treated area and standpipes on terraced fields as well as 66 ft. 

vegetative buffer between the tile outlet and surface water bodies, and 5) restricting loading, 

rinsing, and washing equipment within 300 ft. from surface water bodies or within 50 ft. from 

wells unless conducted on an impervious surface. All setbacks must be planted to a crop or 

seeded with grass or other suitable cover. 

In addition, the registrant has agreed to voluntarily remove from its labels the “over the 

top” application on corn for European corn borer control. Banded applications on corn will also 

require placing granules in a 7 inch band over the row, in front of the press wheel, and 

incorporated into the soil to a depth of 1 inch. To prevent the flow of rainfall down planted 

rows, the label text will read “To prevent channeling of surface water run-off, adjust the planter 

row-cleaners appropriately to prevent rows lower in height than adjacent soil”. 

Benefits 

The benefits of terbufos on corn were estimated using a comparative product 

performance assessment. This assessment aimed at quantifying, to the extent possible, the 

benefits derived from the use of terbufos on corn primarily for control of corn rootworm. It 

relied on data from numerous product performance studies available in the open scientific 

literature. These data were analyzed using statistical methods to determine the relative effects on 

corn yields of using terbufos and other corn insecticides especially tefluthrin. The benefits 

assessment concluded that under most conditions the alternative insecticides produced similar or 

greater yields than fields where terbufos was used. Terbufos did show an advantage over the 

alternatives in controlling billbugs in North Carolina and controlling corn rootworm in the 

Northeast. Terbufos also performed more effectively on some secondary corn pests. However, 

there are uncertainties associated with the assessment that were taken into consideration when 

developing the risk management measures outlined in the IRED. 

For the uses of terbufos the Agency has determined that, with the adoption of all of the 

label amendments noted in this document, use may continue until the outcome of the cumulative 

assessment of all of the organophosphates has been decided. 

The Agency is issuing this interim Reregistration Eligibility Document (RED) for 

terbufos, as announced in a Notice of Availability published in the Federal Register. This 

3
 
interim RED document includes guidance and time frames for complying with any necessary 

label changes for products containing terbufos. There is a 60-day public comment period for this 

document to allow stakeholders the opportunity to review and provide comments on this 

document. With regard to complying with the requirements in this document, the Agency has 

shortened this time period so that the risks identified herein are mitigated as quickly as possible. 

Neither the tolerance reassessment nor the reregistration eligibility decision for terbufos can be 

considered final, however, until the cumulative risks for all organophosphate pesticides are 

considered. The cumulative assessment may result in further required risk mitigation measures 

for terbufos. 

4
 
I. Introduction 

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988 

to accelerate the reregistration of products with active ingredients registered prior to November 

1, 1984. The amended Act calls for the development and submission of data to support the 

reregistration of an active ingredient, as well as a review of all submitted data by the U.S. 

Environmental Protection Agency (referred to as EPA or “the Agency”). Reregistration involves 

a thorough review of the scientific database underlying a pesticide’s registration. The purpose of 

the Agency’s review is to reassess the potential hazards arising from the currently registered uses 

of the pesticide; to determine the need for additional data on health and environmental effects; 

and to determine whether the pesticide meets the “no unreasonable adverse effects” criteria of 

FIFRA. 

On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into 

law. This Act amends FIFRA to require tolerance reassessment of all existing tolerances. The 

Agency had decided that, for those chemicals that have tolerances and are undergoing 

reregistration, the tolerance reassessment will be initiated through this reregistration process. It 

also requires that by 2006, EPA must review all tolerances in effect on the day before the date of 

the enactment of the FQPA, which was August 3, 1996. FQPA also amends the FFDCA to 

require a safety finding in tolerance reassessment based on factors including an assessment of 

cumulative effects of chemicals with a common mechanism of toxicity. Terbufos belongs to a 

group of pesticides called organophosphates, which share a common mechanism of toxicity ­

they all affect the nervous system by inhibiting cholinesterase. Although FQPA significantly 

affects the Agency’s reregistration process, it does not amend any of the existing reregistration 

deadlines. Therefore, the Agency is continuing its reregistration program while it resolves the 

remaining issues associated with the implementation of FQPA. 

This document presents the Agency’s revised human health and ecological risk 

assessments; its progress toward tolerance reassessment; and the interim decision on 

reregistration eligibility for terbufos. It is intended to be only the first phase in the reregistration 

process for terbufos. The Agency will eventually proceed with its assessment of the cumulative 

risk of the OP pesticides and issue a final reregistration eligibility decision for terbufos. 

The implementation of FQPA has required the Agency to revisit some of its existing 

policies relating to the determination and regulation of dietary risk, and has also raised a number 

of new issues for which policies need to be created. These issues were refined and developed 

through collaboration between the Agency and the Tolerance Reassessment Advisory Committee 

(TRAC), which was composed of representatives from industry, environmental groups, and other 

interested parties. The TRAC identified the following science policy issues it believed were key 

to the implementation of FQPA and tolerance reassessment: 

• Applying the FQPA 10-Fold Safety Factor 

• Whether and How to Use "Monte Carlo" Analyses in Dietary Exposure Assessments 

• How to Interpret "No Detectable Residues" in Dietary Exposure Assessments 

5
 
• Refining Dietary (Food) Exposure Estimates 

• Refining Dietary (Drinking Water) Exposure Estimates 

• Assessing Residential Exposure 

• Aggregating Exposure from all Non-Occupational Sources 

•	 How to Conduct a Cumulative Risk Assessment for Organophosphate or Other Pesticides 

with a Common Mechanism of Toxicity 

• Selection of Appropriate Toxicity Endpoints for Risk Assessments of Organophosphates 

• Whether and How to Use Data Derived from Human Studies 

The process developed by the TRAC calls for EPA to provide one or more documents for 

public comment on each of the policy issues described above. Each of these issues is evolving 

and in a different stage of refinement. Some issue papers have already been published for 

comment in the Federal Register and others will be published shortly. 

In addition to the policy issues that resulted from the TRAC process, the Agency issued, 

on Sept. 29, 2000, a Pesticide Registration Notice (PR 2000-9) that presents EPA’s approach for 

managing risks from organophosphate pesticides to occupational users. The Worker PR Notice 

describes the Agency’s baseline approach to managing risks to handlers and workers who may 

be exposed to organophosphate pesticides, and the Agency expects that other types of chemicals 

will be handled similarly. Generally, basic protective measures such as closed mixing and 

loading systems, enclosed cab equipment, or protective clothing, as well as increased reentry 

intervals will be necessary for most uses where current risk assessments indicate a risk and such 

protective measures are feasible. The policy also states that the Agency will assess each 

pesticide individually, and based upon the risk assessment, determine the need for specific 

measures tailored to the potential risks of the chemical. The measures included in this interim 

RED are consistent with the Worker Pesticide Registration Notice. 

This document consists of six sections. Section I contains the regulatory framework for 

reregistration/tolerance reassessment as well as descriptions of the process developed by TRAC 

for public comment on science policy issues for the organophosphate pesticides and the worker 

risk management PR notice. Section II provides a profile of the use and usage of the chemical. 

Section III gives an overview of the revised human health and environmental effects risk 

assessments resulting from public comments and other information. Section IV presents the 

Agency's interim reregistration eligibility and risk management decisions. Section V 

summarizes required label changes based on the risk mitigation and risk reduction measures 

outlined in Section IV. Section VI provides information on how to access related documents. 

Finally, the Appendices lists Data Call-In (DCI) information. The revised risk assessments and 

related addenda are not included in this document, but are available on the Agency's web page 

www.epa.gov/pesticides/op, and in the Public Docket. 

6
 
II. Chemical Overview 

A. Regulatory History 

Terbufos was first registered in the United States in 1974 by EPA for use as a systemic 

insecticide-nematicide on corn. Registrations for the use of terbufos on sugar beets and sorghum 

followed in 1976 and 1982, respectively. A Registration Standard was issued in 1983 and, in 

1988, a Revised Registration Standard was issued for terbufos requiring numerous studies to 

support continued registration. The 1983 Registration standard was amended in February 1985 

to require Restricted Use classification due to acute oral and dermal toxicity. Two Preliminary 

Notifications (i.e., Grassley-Allen letters) were sent to the technical registrant, in 1988 and 1990, 

identifying terbufos as a candidate for Special Review based on risks to nontarget organisms; 

birds, mammals, aquatic species, and endangered species. 

B. Chemical Identification 

Chemical Structure of Terbufos: 

! Common Name: Terbufos 

! Chemical Name: S-[[1,1-dimethylethyl) thio] O,O-di-ethyl 

phosphorodithioate 

! Chemical family: Organophosphate 

! CAS registry number: 13071-79-9 

! OPP chemical code: 105001 

! Empirical formula: C9H21O2PS3 

! Molecular weight: 288.4
 

! Trade and other names: Counter®
 

! Basic manufacturer: BASF Corporation (technical registrant)
 

7
 
Technical terbufos is a colorless to pale yellow clear liquid with a mercaptan-like odor. 

It has a boiling point of 55 EC at 0.02 mm Hg, and a density of 1.11 g/ml at 20 EC. The 

solubility of terbufos in water at 25 EC is 5.4 ppm. Its solubility in acetone, acetonitrile, 

benzene, chloroform, dichloromethane, ethanol, n-heptane, methylene chloride, and toluene is 

reported as $ 100 g/100 ml at 20 EC. Water solubilities of the two major soil/water degradates at 

25 EC are 3214 mg/L and 407 mg/L for terbufos sulfoxide and terbufos sulfone, respectively. 

C. Use Profile 

The following information is based on the currently registered uses of terbufos. 

Type of Pesticide: Systemic insecticide-nematicide 

Summary of Use Sites: 

Food: Terbufos is applied at-plant/at-bedding, post emergent, or at cultivation to 

control many types of insect pests. Registered use sites are corn (field, sweet, and 

pop), sugarbeets, and grain sorghum. Approximately 80 percent of terbufos is 

applied to field corn. Terbufos is also used on imported bananas grown in South 

America and Mexico. 

Residential: None. 

Public Health: None. 

Other Nonfood: None. 

Target Pests: Target pests include corn rootworms, wireworms, white grubs, 

billbugs, sugarbeet root maggots, cutworms, and nematodes. 

Formulation Types Registered: In addition to the technical, there are two enduse formulations registered: a clay-based granular formulation and a polymeric 

granular formulation. 

Method and Rates of Application: 

Equipment - Granular row planters; in front of planter’s press wheel with 

light soil incorporation using, for example, drag chains, tines, or 

cultivators. 

Method and Rate - Applied 1) at-plant/at-bedding (banded, in-furrow, 

knifed-in); 2) post emergent (banded alongside plant); and 3) at 

cultivation. All applications require soil incorporation. 

8
 
•	 The typical application rate for corn is 1.0 lb a.i./A, and the 

maximum application rate for corn is 1.3 lbs a.i./A, applied one 

time per year. A Special Local Need (SLN) registration in North 

Carolina allows use on corn at up to 2.6 lbs a.i./A, one time per 

year. 

•	 The typical application rate for sugarbeets is 1.3 lbs a.i./A and for 

sorghum is 0.7 lbs a.i./A, both limited to one application per year. 

The maximum application rate on these crops is 1.96 lbs a.i./A, 

applied one time per year. 

Timing - At-plant/at-bedding, post-emergent, at-cultivation 

Use Classification: The registered terbufos end-use products are restricted use 

products due to acute oral and dermal toxicity. 

D. Estimated Usage of Pesticide 

This section summarizes the best estimates available for many of the pesticide uses of 

terbufos, based on available pesticide usage information for 1987 to 1996. A full listing of all 

uses of terbufos, with the corresponding use and usage data for each site, has been completed 

and is in the “Quantitative Use Assessment” document, which is available in the public docket. 

The data, reported on an aggregate and site (crop) basis, reflect annual fluctuations in use 

patterns as well as the variability in using data from various information sources. Approximately 

7.5 million pounds of Terbufos a.i. are used annually, according to Agency estimates. 

Table 1. Terbufos Estimated Usage 

Crop Lbs. Active 

Ingredient Applied 

(Wt. Avg.)1 

Percent Crop 

Treated (Likely 

Maximum) 

Percent Crop 

Treated (Wt. Avg.) 

Corn (field, pop) 6,530,000 10% 8% 

Sugar Beets 670,000 43% 35% 

Sorghum 190,000 4% 2% 

Sweet Corn 55,000 6% 5% 

1 Weighted Average is based on data for 1987-1996; the most recent years and more reliable data are weighted more 

heavily. 

The registrant has provided the Agency with proprietary domestic sales figures for 2000. 

It should be noted that while these figures are significantly lower than the Agency estimates 

presented in the table above, the proportions among the crops are comparable. 

III. Summary of Terbufos Risk Assessments 

9
 
Following is a summary of EPA’s revised human health and ecological risk findings and 

conclusions for the organophosphate pesticide terbufos, as fully presented in the documents, 

“Terbufos, Human Health Risk Assessment” dated September 2, 1999, and “Terbufos, Revised 

EFED Reregistration Eligibility Decision (RED) Chapter,” dated August 26, 1999. The purpose 

of this summary is to assist the reader by identifying the key features and findings of these risk 

assessments, and to better understand the conclusions reached in the assessments. 

These risk assessments for terbufos were presented at a September 2, 1999, Technical 

Briefing, which was followed by an opportunity for public comment on risk management. The 

risk assessments presented here form the basis of the Agency’s interim risk management 

decision for terbufos only; the Agency must consider cumulative risks of all the 

organophosphate pesticides before any final decisions can be made. 

A. Human Health Risk Assessment 

EPA issued its preliminary risk assessments for terbufos in August 1998 (Phase 3 of the 

TRAC process). In response to comments and studies submitted during Phase 3, the risk 

assessments were refined and updated. Major revisions to the human health risk assessment are 

listed below: 

–	 Use of new acute and subchronic oral rat neurotoxicity studies in the acute and chronic 

dietary risk assessments. 

–	 Reduction of the FQPA Safety Factor from 3X to 1X, based on reevaluation of the hazard 

and exposure database, including the new acute and subchronic oral rat neurotoxicity 

studies. 

–	 Use of new corn and banana residue field trial studies in the acute and chronic dietary 

risk assessments, in combination with previously submitted field trial data. 

–	 Use of new chemical specific worker exposure studies and formulation-specific 28-day 

rat dermal toxicity studies in the occupational risk assessment. 

–	 Use of separate toxicological endpoints for dermal and inhalation exposures for the 

occupational assessment. 

– 	 Use of the SCI-GROW and PRZM-EXAMS models and new aquatic metabolism data to 

estimate potential environmental concentrations (EECs) of terbufos in drinking water 

through groundwater and surface water. 

1. Dietary Risk from Food 

a. Toxicity 

10
 
The Agency has reviewed all toxicity studies submitted and has determined that the 

toxicity database is sufficiently complete, and that it supports an interim reregistration eligibility 

determination for all currently registered uses. Further details on the toxicity of terbufos can be 

found in the September 2, 1999 Human Health Risk Assessment. A brief overview of the studies 

used for the dietary risk assessment is outlined in Table 2 in this document. 

b. FQPA Safety Factor 

The FQPA Safety Factor was reduced to a 1X. Based on a weight-of-the-evidence 

evaluation of the hazard and exposure database for terbufos, there is no indication of increased 

susceptibility of young rats or rabbits to terbufos. Therefore, the additional 10X factor as 

required by FQPA was reduced to 1X. Terbufos did not cause acute delayed neurotoxicity in 

hens given a single oral dose of terbufos, and there was no evidence of neuropathology in the 

acute, subchronic, and chronic studies in dogs or a long-term mouse study. The toxicity database 

includes acceptable acute and subchronic neurotoxicity studies in rats, which were data gaps 

previously. In the rat acute neurotoxicity study, no effects were observed on motor activity, but 

several functional observational battery (FOB) parameters (e.g., ataxia, decreased forelimb grip 

strength, tremors) were affected. No treatment-related effects were observed on motor activity 

or in the FOB parameters measured in the rat subchronic neurotoxicity study. In the 

developmental and reproduction studies, effects were observed in fetuses/offspring only at or 

above treatment levels, which resulted in evidence of parental toxicity. The dietary food 

exposure assessment does not underestimate potential exposures to infants and children from 

terbufos residues in food. No exposure is expected to infants and children from residential (nonoccupational) sources because terbufos is only registered on three agricultural crops. 

Table 2. Summary of Toxicological Endpoints and Other Factors Used in the Human 

Dietary Risk Assessment for Terbufos. 

Exposure 

Scenario 

Dose 

(mg/kg/day) 

Endpoint Study UF FQPA 

Safety 

Factor 

PAD 

(mg/kg/day) 

Acute 

Dietary 

NOAEL = 

0.15 

Plasma ChE 

inhibition in 

both sexes and 

clinical signs. 

Acute Oral 

Neurotoxicity in Rats 

(MRID 44672003) 

500 1X 0.0003 

mg/kg/day 

Chronic 

Dietary 

NOAEL = 

0.005 

Plasma ChE 

inhibition in 

both sexes. 

Chronic 1-year and 

subchronic oral 

toxicity in dog (MRIDs 

00263678, 40374701) 

100 1X 0.00005 

mg/kg/day 

11
 
c. Population Adjusted Dose (PAD) 

The PAD is a term that characterizes the dietary risk of a chemical, and reflects the 

Reference Dose (RfD), either acute or chronic, that has been adjusted to account for the FQPA 

safety factor (i.e., RfD/FQPA safety factor). A risk estimate that is less than 100% of the acute 

or chronic PAD does not exceed the Agency’s risk concern. The RfD is calculated by taking the 

no observed adverse effect level (NOAEL) from an appropriate toxicity study and dividing it by 

an uncertainty factor (UF) (i.e., NOAEL/UF). In the case of terbufos, the FQPA safety factor is 

1X; therefore, the RfD equals the PAD. 

The acute PAD for terbufos is 0.0003 mg/kg/day (0.15 mg/kg/day/500) based on plasma 

ChE and clinical signs observed in the acute rat neurotoxicity study. The UF of 500 is calculated 

as follows: 10X for interspecies extrapolation x 10X for intraspecies variability x 5X for 

differences in sensitivity between rats and dogs. The additional UF of 5X is required based on 

an analysis of plasma ChE in the rat subchronic neurotoxicity study and a 28-day oral toxicity 

study in dogs. The analysis was performed to determine a species sensitivity factor that would 

be appropriate to apply to the rat acute neurotoxicity study. Previously, EPA had selected results 

from the 28-day dog toxicity study for the acute endpoint, which had a plasma ChE measurement 

at day 7. Using the rat acute neurotoxicity study for the endpoint with a derived species 

sensitivity factor provides the appropriate time-related endpoint and takes into account the 

observed sensitivity between the rat and dog. 

The chronic PAD for terbufos is 0.00005 mg/kg/day (0.005 mg/kg/day ÷ 100) based on 

plasma ChE observed in a 28-day oral toxicity study in dogs (NOAEL = 0.005 mg/kg/day) and a 

1-year oral toxicity study in dogs. 

d. Exposure Assumptions 

Revised acute and chronic dietary risk analyses for terbufos were conducted with the 

Dietary Exposure Evaluation Model (DEEMTM). DEEM incorporates consumption data 

generated in USDA’s Continuing Surveys of Food Intakes by Individuals (CSFII), 1989-91. 

The acute dietary analysis uses anticipated residue values from crop residue field trial 

studies, and percent crop-treated figures. The chronic dietary analysis was refined using 

anticipated residue values from crop residue field trial studies, and weighted average percent 

crop treated figures. The dietary exposure analyses for terbufos are based largely on residue 

values from field trial data below the limit of detection (LOD), between the LOD and limit of 

quantitation (LOQ), or at the LOQ. The Agency considered using monitoring data from 

USDA’s Pesticide Data Program (PDP) and FDA enforcement monitoring data available for 

terbufos on bananas and sweet corn, but determined that these data are not appropriate for use in 

this risk assessment for several reasons, including that the monitoring effort did not measure all 

the terbufos degradates of concern. It should also be noted that exposure from coffee beans 

treated with terbufos was included in the dietary assessment because a proposal to extend the 

time-limited tolerance for that commodity is currently pending. 

12
 
e. Food Risk Characterization 

Generally, a dietary risk estimate that is less than 100% of the acute or chronic 

Population Adjusted Dose does not exceed EPA’s risk concerns. The terbufos acute dietary risk 

from food alone is below the Agency’s level of concern—that is, less than 100% of the acute 

PAD is used. For example, for the most exposed subgroups, non-nursing infants and infants (< 1 

year), the percent acute PAD values are 86% and 82%, respectively, at the 99.9th percentile of 

exposure from consumption of food alone. 

The chronic dietary risk from food alone is well below the Agency’s level of concern. 

For the most exposed subgroups, infants, the percent chronic PAD values are no more than 9%. 

Both the acute and chronic dietary exposure and risks associated with terbufos are below 

the Agency’s level of concern. To further characterize acute dietary risk, additional analysis 

were conducted indicating that bananas are the most significant contributor to the estimated 

acute dietary risk from food alone. Both the acute and chronic dietary risk assessments are 

considered to be refined using the data available. However, the acute and chronic analyses do 

not take into consideration the potential for reduction or concentration of terbufos residues in 

cooked/canned/processed bananas and sweet corn, since there are no chemical-specific cooking 

studies available. EPA could refine the terbufos dietary exposure analysis if these data were 

generated and could be further refined if appropriate monitoring data were available. It should 

be noted that the available PDP monitoring data, while not appropriate for the purposes of 

quantitative risk assessment, found no detections of terbufos or terbufos sulfone residues in over 

100 samples of sweet corn. Any and all available refinements will be considered when the 

cumulative assessment for all of the organophosphates is conducted. 

2. Dietary Risk from Drinking Water 

Drinking water exposure to pesticides can occur through ground water and surface water 

contamination. EPA considers both acute (one day) and chronic (lifetime) drinking water risks 

and uses either modeling or actual monitoring data, if available, to estimate those risks. 

Modeling is considered to be an unrefined assessment and provides a high-end estimate of risk. 

The GENEEC and PRZM-EXAMS models were used to estimate surface water 

concentrations, and SCI-GROW was used to estimate groundwater concentrations. All of these 

are considered to be screening models, with the PRZM-EXAMS model being somewhat more 

refined than the other two. 

In the case of terbufos, EPA is concerned about the potential for parent terbufos and its 

two major degradates in water, terbufos sulfoxide and terbufos sulfone, to runoff to surface water 

sources, and the potential for these degradates to leach to groundwater sources. The PRZMEXAMS model was used to estimate surface water concentrations, and SCI-GROW was used to 

estimate groundwater concentrations. Although some monitoring data for terbufos were 

13
 
available, these data were deemed of limited value for several reasons, including that the 

degradates of concern were typically not included as part of the analyses. Further discussion 

follows below regarding the monitoring data the Agency considered for terbufos. EPA also 

reviewed and considered new environmental fate data submitted on the abiotic hydrolysis and 

aerobic aquatic metabolism of parent terbufos and its degradates. 

a. Surface Water 

The Tier II PRZM-EXAMS screening model is used to estimate upper-bound 

environmental concentrations (EECs) in drinking water derived from surface water. This model, 

in general, is based on more refined, less conservative assumptions than the Tier I GENEEC 

screening model. Acute modeled EECs for terbufos parent and its degradates, terbufos sulfoxide 

and terbufos sulfone, in surface water range from 5.4 ppb to 13.3 ppb, depending on the crop 

site. Chronic modeled EECs for terbufos parent and its degradates range from 1.3 ppb to 5.5 

ppb, depending on the crop site. 

The Agency also used the recently implemented Index Reservoir (IR) and Percent Crop 

Area (PCA) modifications to the Tier II PRZM-EXAMS model to calculate upper-bound EECs 

for terbufos and its degradates in drinking water derived from surface water. Applying the IR 

and PCA modifications, acute modeled EECs for terbufos parent and its degradates, terbufos 

sulfoxide and sulfone, in surface water range from 8.4 ppb to 25.5 ppb depending on the crop 

site. Chronic modeled EECs for terbufos parent and its degradates, terbufos sulfoxide and 

sulfone, range from 1.8 ppb to 5.9 ppb, depending on the crop site. 

The surface water model assumes terbufos applications are made at the maximum rate for 

each crop on the current label, using the labeled methods of application (i.e., T-banded, infurrow, or knifed-in). In addition, the Agency applied the standard assumption that 85 percent of 

the applied end-use product granules would be found in the top two cm of the soil. Finally, halflife inputs in the model were derived using direct measurements of terbufos parent and its 

degradates from aerobic aquatic metabolism data (MRID 44862502), rather than default or 

“worst-case” assumptions, which provides additional refinement to the terbufos modeling. 

Monitoring for terbufos in surface water is limited and has been undertaken by U.S. 

Geological Survey (USGS) in its National Water Quality Assessment (NAWQA) program and 

by some states. Terbufos parent was not found above 2.25 ppb in monitoring data. The Agency 

believes that the terbufos monitoring data available are limited and often not associated with 

periods of terbufos use. For instance, samples were often taken throughout the year rather than 

concentrating sampling during the time period when terbufos application is expected. 

Furthermore, the degradates of concern, terbufos sulfoxide and sulfone, were not included in any 

of the analyses. Given these limitations, the existing surface water monitoring database cannot 

be used to estimate concentrations of terbufos in surface water. However, the Agency notes that 

the available NAWQA data found 17 detections of parent terbufos in 5,198 samples. The 

detections ranged from 0.013 ug/L to 0.56 ug/L. 

14
 
b. Ground Water 

The Tier I screening model, SCI-GROW, was used to estimate drinking water 

concentrations derived from groundwater. Acute and chronic EECs for terbufos parent and its 

degradates, terbufos sulfoxide and sulfone, in groundwater range from 4.8 ppb to 7.4 ppb. The 

groundwater modeling assumes applications are made at the maximum rate for each crop on the 

current label, using the labeled methods of application (i.e., T-banded, in-furrow, or knifed-in). 

The half-life inputs in the model are derived from direct measurements of terbufos parent and its 

degradates from an aerobic soil metabolism study (MRID 00156853). 

Monitoring of groundwater supplies for terbufos has been limited. Information on 

terbufos in groundwater has been gathered by the registrant, USGS NAWQA, EPA’s Pesticides 

in Groundwater Database, and some states within the major use areas. These data represent 

4,563 samples from 13 states, including 20 detections of parent terbufos with an additional 7 

apparent detections in Iowa that are questionable or unconfirmed. Thirteen wells were also 

sampled in Iowa for terbufos sulfone, but no residues were detected. Detections of Terbufos 

parent in groundwater studies has ranged from 0.011 ppb up to 20.0 ppb. However, only two 

detections were about 0.06 ppb. EPA has determined that the groundwater monitoring data 

available to the Agency are inadequate for use in assessing groundwater exposures for several 

reasons, including that the monitoring studies did not analyze for the degradates of concern. 

c. Drinking Water Levels of Comparison (DWLOCs) 

To determine the maximum allowable contribution of water-containing pesticide residues 

permitted in the diet, EPA first looks at how much of the overall allowable risk is contributed by 

food (and if appropriate, residential uses) then determines a “drinking water level of 

comparison”(DWLOC) to determine whether modeled or monitoring levels exceed this level. 

The Agency uses the DWLOC as a surrogate to capture risk associated with exposure from 

pesticides in drinking water. The DWLOC is the maximum concentration in drinking water 

which, when considered together with dietary exposure, does not exceed a level of concern. 

The results of the Agency’s drinking water analysis are summarized here. Details of this 

analysis, which used screening models, are found in the HED Human Health Risk Assessment 

dated September 2, 1999 and the EFED Environmental Risk Assessment dated August 26, 1999. 

For acute risk, groundwater and surface water EECs exceed the acute DWLOCs for 

infants and children (Table 3). Even if it is assumed that there are no food exposures to terbufos, 

drinking water alone, based on model estimates, would result in exceedences of the risk cup, 

particularly for infants and children. The table below presents the calculations for the acute 

drinking water assessment. 

Table 3. Summary of DWLOC Calculations for Acute Risk 

15
 
Population 

Subgroup 

Acute PAD 

(mg/kg/day) 

Food 

Exposure 

(mg/kg/day) 

Allowable 

Water 

Exposure 

(mg/kg/day) 

Maximum 

Groundwater 

EECs (SCIGROW, total 

toxic residue, 

ppb) 

Maximum 

Surface Water 

EECs (PRZM/ 

EXAMS, total 

toxic residue, 

ppb) 

Maximum 

Surface Water 

EECs (PRZM/ 

EXAMS, IR & 

PCA 

modifications, 

total toxic 

residue, ppb) 

DWLOC 

(ppb) 

U.S. 

Population 3.0e-4 7.0e-5 2.3e-4 7.4 13.3 25.5 8.10 

Nonnursing 

Infants 

(<1 yr) 

3.0e-4 2.6e-4 4.1e-5 7.4 13.3 25.5 0.41 

All Infants 

(<1 yr) 3.0e-4 2.5e-4 5.0e-5 7.4 13.3 25.5 0.50 

Children 

(1-6 years) 3.0e-4 1.4e-4 1.6e-4 7.4 13.3 25.5 1.60 

Children 

(7-12 

years) 

3.0e-4 6.9e-5 2.3e-4 7.4 13.3 25.5 2.30 

For chronic risk, groundwater and surface water EEC’s exceed the chronic DWLOC’s for 

all population subgroups, regardless of the treated crop (Table 4). Even if it is assumed that 

there are no food exposures to terbufos, drinking water alone, based on model estimates, would 

result in exceedences of the risk cup, particularly for infants and children. The table below 

presents the calculations for the chronic drinking water assessment. 

16
 
Table 4. Summary of DWLOC Calculations for Chronic Risk 

Population 

Subgroup 

Chronic 

PAD 

(mg/kg/day) 

Food 

Exposure 

(mg/kg/day) 

Allowable 

Water 

Exposure 

(mg/kg/day) 

Maximum 

Groundwater 

EECs ( SCIGROW, total 

toxic residue, 

ppb) 

Maximum 

Surface Water 

EECs (PRZM/ 

EXAMS, total 

toxic residue, 

ppb) 

Maximum 

Surface Water 

EECs (PRZM/ 

EXAMS, IR & 

PCA 

modifications, 

total toxic 

residue, ppb) 

DWLOC 

(ppb) 

U.S. 

Population 5.0e-5 1.0e-6 4.9e-5 7.4 5.5 5.9 1.70 

Nonnursing 

infants 

(<1 yr) 

5.0e-5 5.0e-6 4.5e-5 7.4 5.5 5.9 0.45 

All Infants 

(<1 yr) 5.0e-5 4.0e-6 4.6e-5 7.4 5.5 5.9 0.46 

Children 

(1-6 years) 5.0e-5 2.0e-6 4.8e-5 7.4 5.5 5.9 0.48 

Children 

(7-12 

years) 

5.0e-5 1.0e-6 4.9e-5 7.4 5.5 5.9 0.49 

The acute and chronic dietary risks from drinking water exposure are above the Agency’s 

level of concern for most subpopulations. However, there are uncertainties which lead the 

Agency to expect that exposure from drinking water may not be as high as the levels used in the 

development of the risk assessment. These uncertainties are described in Section IV. 

3. Aggregate Risk 

An aggregate risk assessment looks at the combined risk from dietary exposure (food and 

drinking water routes). Acute and chronic aggregate risk assessments were conducted for 

terbufos. Since terbufos is not registered for use in residential settings, residential exposures are 

not expected, and aggregate short- and intermediate-term exposures were not estimated. Results 

of the aggregate risk assessment are summarized here, and are discussed in the terbufos human 

health risk assessment. 

The Agency was only able to quantify food sources of dietary exposure to terbufos 

because dietary exposures through drinking water have only been estimated using models. 

Neither adequate groundwater or surface water monitoring data were available to estimate 

potential drinking water exposures to terbufos and its degradates. 

Acute Aggregate Risk Assessment: Potential acute dietary risks from food sources alone 

do not exceed the Agency’s level of concern. The most exposed subpopulation, non-nursing 

infants, consume 86% of the acute PAD at the 99.9th percentile of exposure, based on highly 

refined exposure estimates. However, when drinking water exposure concentrations, derived 

17
 
from groundwater and surface water models, are added to the acute dietary risk assessment, the 

potential exists for acute dietary exposures through drinking water that exceed the acute 

DWLOCs, resulting in acute aggregate risks of concern. 

Chronic Aggregate Risk Assessment: In the case of the food component of the chronic 

aggregate risk assessment, risks are well below the Agency’s level of concern. No more than 9% 

of chronic PAD is consumed for infants. However, based on modeled estimates of terbufos 

concentrations in groundwater and surface water, the potential exists for chronic dietary 

exposures through drinking water that exceed the chronic DWLOCs, resulting in chronic 

aggregate risks of concern. 

4. Occupational and Residential Risk 

Occupational workers can be exposed to a pesticide through mixing, loading, and/or 

applying a pesticide, or re-entering treated sites. Terbufos is not registered for use in residential 

settings so homeowner or non-occupational exposures are not expected. Occupational handlers 

of terbufos include individual farmers or growers who load and/or apply pesticides, and 

professional or custom agricultural applicators. Risk for all of the potentially exposed 

populations is measured by a Margin of Exposure (MOE) which determines how close the 

occupational exposure comes to a No Observed Adverse Effect Level (NOAEL). Generally, 

MOEs greater than 100 are considered to not exceed EPA’s risk concern. 

a. Toxicity 

The toxicity of terbufos is integral to assessing the occupational risk. All risk 

calculations are based on the most current toxicity information available for terbufos including a 

28 day dermal toxicity study. The toxicological endpoints, and other factors used in the 

occupational risk assessment for terbufos are listed below in Table 5a. The endpoints selected 

for the dermal and inhalation risk assessments have been applied to both short-term and 

intermediate-term exposure scenarios. 

18
 
Table 5a. Summary of Toxicological Endpoints and Other Factors Used in the Human 

Occupational Risk Assessments for terbufos 

Assessment Dose Endpoint Study Absorption 

factor 

Short-term and 

IntermediateTerm dermal 

Counter 15G: NOAEL 

= 0.32 mg/kg/day 

Counter CR: NOAEL = 

2.0 mg/kg/day 

plasma and 

brain ChE 

inhibition 

plasma and 

RBC ChE 

inhibition 

28-day dermal toxicity study in 

rats using Counter 15G (MRID 

44520501) 

28-day dermal toxicity study in 

rats using Counter CR (MRID 

44690501) 

NA1 

Short-term and 

Intermediateterm inhalation 

NOAEL = 0.0035 

mg/kg/day2 

Red blood cell, 

plasma, and 

brain ChE 

inhibition 

90-day subchronic inhalation 

study in rats (MRID 00258710) 

100% 

1

A dermal absorption factor is not required for terbufos since product-specific data were available from two dermal
 

toxicity studies.
 2

Calculated as follows: 0.00001 mg/L x 100% absorption x 43.5 L/hr/kg for rat strain x 8 hour duration x 1 activity
 

factor = 0.0035 mg/kg/day.
 

In acute toxicity studies, terbufos exhibits severe acute toxicity via the oral, dermal, and 

inhalation routes of exposure (Table 5b). Terbufos is also considered to be a severe eye and 

dermal irritant, although dermal and eye irritant assessments were not possible due to death of all 

test animals within 24 hours of exposure in the eye and dermal irritation studies. The dermal 

sensitization study was waived due to lethality. 

Table 5b. Acute Toxicity Profile for Occupational Exposure for terbufos 

Route of 

Exposure 

Toxicity 

Category 

Category Basis Study Type and Results MRID No. 

Oral I LD50 # 50 mg/kg Acute oral toxicity study in rats, 

LD50 .1.5 mg/kg 

00029863 

Dermal I LD50 # 200 mg/kg Acute dermal toxicity study in rabbits, 

LD50 = 0.87 mg/L males and females 

00258710 

Inhalation I LC50 # 0.05 mg/L Acute inhalation study in rats, 

LC50 = 1.7 Fg/L 

41538101 

Eye Irritation I Corrosive Primary eye irritation study in rabbits, 

all animals died within 24 hrs of exposure 

00044957 

Dermal 

Irritation 

I Corrosive Primary skin irritation study in rabbits, 

all animals died within 24 hrs of exposure 

00044957 

Dermal 

Sensitizer 

NA NA Waived due to lethality NA 

b. Exposure 

19 
Two chemical- and scenario-specific occupational exposure studies were submitted to 

support the terbufos reregistration: 

1) 	 Exposure of farm workers to terbufos while loading Counter 15G with a Lock-NLoad closed handling system and applying Counter 15G to corn at planting time 

(closed cab applications) (MRID 44793301, Exhibit 1). 

2) 	 Exposure of farm workers to terbufos while loading Counter CR from open bags 

and applying to corn at planting time (open cab applications) (MRID 44793301, 

Exhibit 2). 

In addition, a method validation study (MRID 44793301) was submitted to establish the 

parameters for the analytical methods used in the occupational exposure studies. These studies 

were reviewed and accepted by the Agency, and are being used in the terbufos occupational risk 

assessment. The Agency also used the Pesticide Handlers Exposure Database (PHED) for risk 

characterization purposes to evaluate occupational risks at reduced levels of personal protection 

and engineering controls. 

Generally, results from the occupational exposure studies indicate low exposures to 

loaders and applicators when using high levels of PPE and closed loading. Terbufos was not 

detected in many of the exposure scenarios for which it was monitored in the studies. A large 

percentage of the exposure values were either below the limit of detection (LOD) or limit of 

quantification (LOQ). Figures used to calculate unit exposure values in these cases were 1⁄2 the 

LOD or LOQ. Refer to the occupational risk assessment dated August 26, 1999, for additional 

information on results from these two studies. 

When conducting occupational risk assessments, EPA usually combines chemicalspecific data with PHED data to obtain a more robust data set. The terbufos worker exposure 

studies, however, have not been integrated with PHED because the Agency believes physical 

differences in the formulations and packaging preclude combining the data with PHED. The 

terbufos studies are also unique because they represent a slightly higher level of personal 

protection than is typically considered using PHED. In the study, an enclosed cab was used for 

application with the windows open in an attempt to simulate open cab conditions. In PHED, 

applicators in an enclosed cab only wear baseline PPE, however, in this study, applicators wore 

maximum personal protective equipment. 

The Agency uses a concept known as unit exposure as the basis for job scenarios used to 

assess occupational exposures to pesticides. Unit exposures represent the estimated exposures a 

pesticide handler would receive when making a particular application. EPA has developed a 

series of unit exposures unique to each type of job scenario in PHED. For terbufos, unit 

exposures were calculated by the registrant from the occupational exposure studies representing 

the minimum, maximum, and geometric mean values. These values have been verified by the 

Agency, and are being used in the risk assessment to represent typical to maximum exposures. 

The geometric mean values (a measure of the central tendency of the data) are the closest 

20
 
approximation of the unit exposure values, and are the values used to determine whether the 

exposures exceed the Agency’s level of concern. 

Anticipated use patterns, application methods, and range of application rates were 

derived from the current terbufos labeling. Application rates for crops specified on the terbufos 

labeling range from 1.3 to 2.0 lbs. a.i./A. A Special Local Need (SLN) registration in North 

Carolina allows use on corn up to 2.6 lbs a.i./A. 

Because chemical- and scenario-specific occupational exposure studies are available for 

terbufos, the combinations of engineering controls and personal protective equipment (PPE) 

evaluated in the risk assessment are slightly different than combinations typically considered by 

the Agency. First, all Counter 15G is loaded using a Lock-N-Load, closed handling system, 

whereas Counter CR formulation is available in both Lock-N-Load packaging and open bags. 

Secondly, current terbufos labels require applicators and other handlers to wear coveralls over 

long-sleeved shirt and pants, waterproof gloves, chemical-resistant footwear plus socks, 

protective eye-wear, chemical-resistent headgear, a chemical-resistent apron, and a PF 10 APR 

respirator. The levels of protection that form the basis for the terbufos exposure calculations are: 

•	 Baseline: Long-sleeved shirt and long pants, shoes and socks. [Note: 

This scenario was used only for exposure data developed 

using the Pesticide Handlers Exposure Database] 

•	 Minimum PPE: Baseline + chemical resistant gloves and a dust/mist 

respirator with a protection factor of 5. [Note: This scenario 

was used only for exposure data developed using the 

Pesticide Handlers Exposure Database] 

•	 Maximum PPE: Baseline + coveralls, chemical resistant gloves, and an air 

purifying respirator with a protection factor of 10. [Note: 

This scenario was used for exposure data developed using 

the Pesticide Handlers Exposure Database and Counter 20 

CR chemical- and scenario specific exposure monitoring 

studies] 

•	 Engineering controls: Engineering controls such as an enclosed cab tractor or 

closed loading system for granulars. [Note: This scenario 

was used only for exposure data developed using the 

Pesticide Handlers Exposure Database] 

•	 Engineering controls + PPE: Engineering controls such as an enclosed cab tractor or 

closed loading system for granulars with associated PPE 

required by the WPS when engineering controls are used 

(e.g., apron and chemical resistant gloves). [Note: This 

scenario was used only for exposure data developed from 

21
 
the Counter 15 G chemical- and scenario specific exposure 

monitoring studies] 

A chemical can produce different effects depending on how long a person is exposed to 

it, how frequently any exposures occur, and the level of exposure. For terbufos, EPA completed 

occupational risk assessments for short- and intermediate-term duration, to reflect potential 

exposures from 1-30 days up to several months. Some applicators may apply terbufos over a 

period of weeks because they may need to cover large acreage, or they may be professional 

applicators completing numerous applications within a region. A chronic risk assessment was 

not conducted for terbufos because exposures of a chronic duration are not expected. 

c. Occupational Handler Risk Summary 

In the revised risk assessment, risks to handlers has been assessed using separate 

toxicological endpoints for both dermal and inhalation exposures because the dose levels at 

which effects occur differ depending on whether terbufos was deposited on the skin or inhaled. 

In addition, the Agency selected two sets of dermal endpoints to assess dermal exposures 

because the physical nature of each formulated product has different impacts on dermal toxicity. 

A single endpoint has been selected to assess inhalation exposures for both granular formulations 

because only a single study was available. The resulting risks (MOE values) were then added to 

obtain an overall risk for handlers that accounted for both dermal and inhalation exposures. 

These endpoints are believed to be appropriate for both short- and intermediate-term risk 

assessment. All the risk calculations for handlers completed in this assessment are included in 

Appendix A of the Occupational and Residential Exposure (ORE) Chapter dated August 26, 

1999. 

Analyses were conducted to determine the MOEs at typical and maximum application 

rates, and at typical and maximum acreage-treated for the different exposure scenarios. Each of 

these analyses is included in Appendix A, Tables 1-14 of the ORE Chapter. The following 

tables in this document, summarize the exposure scenarios at maximum application rates and 

acreage-treated. 

1) Agricultural Handler Risk 

For terbufos, combinations of target crops, application rates, acreage treated, and worker 

scenarios were assessed for short- and intermediate-term exposures for each of the end-use 

products. The Agency has some remaining risk concerns for exposure scenarios assessed for the 

Counter 15G and Counter 20CR formulations when used in a manner consistent with the 

parameters in the occupational exposure studies. 

Counter 15G is only available in closed system packaging (i.e., Lock-N-Load) according 

to the registrant, and therefore the Agency did not assess other types of packaging for the 

product. The registrant used the occupational exposure study for Counter 15G, which was 

conducted using tractors with enclosed cabs and open windows, to extrapolate to an open cab 

application exposure scenario. The Agency does not believe this is a valid approach for 

22
 
assessing open cab exposures for Counter 15G given the study’s reliance on unrefined protection 

factors and since empirical data exist in PHED for this scenario. Instead, the Agency used this 

data to assess exposures for closed cabs scenarios even though the registrant believes the study 

represents open cab conditions. Current labels do not require the use of an enclosed cab during 

application. The occupational exposure study for Counter 20CR was conducted with open bag 

packaging and open cabs. 

Based on the PHED data (maximum PPE), the Agency has risk concerns for loading and 

applying Counter 15G (Table 6). However, based on the chemical specific study, the Agency 

has risk concerns only for loading Counter 15G (Table 6). This study determined that applying 

15G with a closed cab is not of concern. 

The Counter 20CR formulation is available in open bag packaging and closed (Lock-NLoad) packaging. For Counter 20CR in open bag and open cab, the Agency also has risk 

concerns for some exposure scenarios (Table 7). There are no risk concerns when the Counter 

20CR formulation is used in closed systems (Lock-N-Load) and open or closed cabs. 

All the MOEs in the tables below are based on combined dermal and inhalation MOEs. 

The scenario numbers correspond to the scenario numbers detailed and discussed in Appendix A 

of the ORE Chapter. The current labels do not require an enclosed cab for application of 

terbufos. Thus the remaining risk concerns for Counter 15G are based on the chemical specific 

study for loading and PHED data (maximum PPE). For Counter 20CR, the remaining risk 

concerns are based on the chemical specific study. The scenarios with remaining risk concerns 

are: 

(1b) Loading Counter 15G in closed system using the North Carolina SLN 2x 

rate on corn, the maximum rate/acreage on sugar beets, and the maximum 

rate/acreage on sorghum.; 

(2b) Applying Counter 15G in open cabs (maximum PPE) using the maximum 

rate/acreage on corn, the North Carolina SLN 2x rate on corn, the 

maximum rate/acreage on sugar beets, and the maximum rate/acreage on 

sorghum.; 

(1c) Loading Counter 20CR in open bags using the North Carolina SLN 2x 

rate on corn, the maximum rate and acreage on sugar beets, the maximum 

rate and acreage on sorghum.; 

Table 6 describes the short- and intermediate-term MOEs derived from PHED and 

chemical specific data for Counter 15G exposure scenarios. Table 7 describes the short- and 

intermediate-term MOEs derived from the Agency’s use of the chemical specific worker 

exposure studies for Counter 20CR. 

It is notable that inhalation exposures are driving the Agency’s risk concern for the 

occupational scenarios in question rather than dermal exposures. In addition, the risk concern 

for handlers using Counter on corn is associated with a North Carolina Special Local Need 

(SLN) registration. This use on corn is twice the labeled maximum rate (2.6 lbs a.i./A). 

23
 
24
 
Table 6. Counter 15G, Agricultural Uses: Completed using PHED and chemical specific 

data, combined dermal & inhalation MOEs. 

Short-Term and Intermediate-Term MOEs 

Scenario Crop Type Rate Acres Maximum PPE (PHED 

data) 

Eng. Controls (chemical 

specific data1

) 

(1b) Loading 

Counter 15G 

formulation in 

lock-n-load 

containers 

Corn 1.3 213 4.3 105.2 

2.6 213 2.1 52.6 

2.6 150 n.c.2 75 

Sugar Beets 1.96 213 2.8 69.8 

1.96 130 4.6 114 

Sorghum 1.96 213 2.8 69.8 

1.7 213 n.c. 81 

(2b) Applying 

Counter 15G 

Corn 1.3 213 5.3 314.4 

2.6 213 2.7 157.2 

Sugar Beets 1.96 213 3.5 208.6 

Sorghum 1.96 213 3.5 208.6 

1

 For loading- Chemical-resistant apron over long pants, long sleeve shirt, shoes, socks, chemical-resistant gloves. 

For applying- Enclosed cabs 2

 Not calculated 

Table 7. Counter CR, Agricultural Uses: Completed using chemical specific data, 

combined dermal & inhalation MOEs 

Short-Term and Intermediate-Term MOEs 

Scenario Crop Type Rate Acres Max. PPE1

 without 

respirator 

Max. PPE1 with respirator

2 

(1c) Loading 

Counter CR 

Formulation in 

Open Bags 

Corn 1.3 213 13.0 128.7 

2.6 213 6.5 64.4 

Sugar Beets 1.96 213 8.6 85.4 

1.96 130 n.c.3 140 

Sorghum 1.96 213 8.6 85.4 

1.7 213 n.c. 98 

(2c) Applying 

Counter 20 CR 

Corn 1.3 213 687.0 5752.0 

2.6 213 343.5 2876.0 

Sugar Beets 1.96 213 455.7 3815.1 

25
 
Short-Term and Intermediate-Term MOEs 

Scenario Crop Type Rate Acres Max. PPE1

 without 

respirator 

Max. PPE1 with respirator

2 

Sorghum 1.96 213 455.1 3815.1 

1

 For loading- Apron over long pants, long sleeve shirt, shoes, socks, and chemical-resistant gloves. 

For applying- Coveralls over long pants, long sleeve shirt, shoes, socks, and chemical-resistant gloves. 2

 Respirator = PF 10 3

 Not calculated 

2) Post-Application Occupational Risk 

EPA does not believe there is a significant potential for post-application exposures to 

terbufos based on application methods, timing, and frequency. In addition, the Agency does not 

believe there is significant potential for drift into adjoining areas such as residential areas since 

the product is soil incorporated in granular form using ground equipment only. Terbufos use in 

residential areas is not permitted. Given these factors, the Agency concludes that the Restricted 

Entry Intervals (REIs) established under EPA’s Worker Protection Standards (WPS) are 

sufficient to protect workers who may re-enter treated areas. The REI for areas treated with 

terbufos is 48 hours and 72 hours in areas where average annual rainfall is less than 25 inches 

per years. 

B. Environmental Risk Assessment 

A summary of the Agency’s environmental risk assessment is presented below. For a 

detailed discussion on all aspects of the environmental risk assessment, see the Environmental 

Fate and Effects Division chapter, dated August 26, 1999, available in the public docket, and 

supporting documents dated August 20 and August 5, responding to comments from the 

registrant and other stakeholders. 

Several revisions have been made since the preliminary risk assessment was completed, 

and include: 

•	 modifications to the ecological risk assessment and characterization, including an update 

of the Agency’s aquatic and terrestrial incident database, based on information supplied 

by states, the registrant, and other stakeholders. 

•	 consideration of new environmental fate data submitted on the abiotic hydrolysis and 

aerobic aquatic metabolism of parent terbufos and its degradates. 

•	 revisions to the estimated concentrations of terbufos and its degradates in surface water 

and groundwater using the PRZM-EXAMS and SCI-GROW models; 

•	 use of index reservoir and percent crop area modifications to the PRZM-EXAMS 

modeling, and the available environmental fate data for terbufos, to estimate terbufos and 

its degradates in surface water used for drinking water. 

26
 
EPA has used the quotient method to evaluate potential risks to nontarget organisms from 

use of terbufos. Applying this method, risk quotients (RQs) have been calculated by comparing 

estimated concentrations of terbufos in the environment (or EECs) to results from ecological 

toxicity studies in a variety of organisms. A finding of concern results when an RQ exceeds a 

level of concern (LOC), which is a value calculated based on the category of nontarget organism 

and category of concern. EPA has further characterized the ecological risk to nontarget 

organisms for terbufos based on terrestrial field studies and adverse aquatic and terrestrial 

incidents reported to the Agency associated with the use of terbufos on corn. 

1. Environmental Fate and Transport 

The environmental fate database for terbufos is mostly complete, and provides a 

comprehensive understanding of terbufos fate and transport in the environment. 

a. Degradation and Mobility 

Based on a review of the environmental fate database for terbufos, total toxic residues of 

terbufos (parent + degradates) are considered to be highly mobile and persistent. Hydrolysis and 

microbial degradation are the primary dissipation processes for terbufos in the environment 

when it is incorporated into the soil as required by the current label. The linear metabolic halflife of parent terbufos in aerobic soil is approximately 27 days (5.6 days for non-linear). Under 

abiotic (i.e., not biological) conditions, the hydrolysis half-life for parent terbufos is 12.3 to 13.7 

days in the typical range of environmental pH values (pHs 5,7, and 9). Volatilization may be a 

major dissipation route for the portion of parent terbufos that remains on the soil surface after 

incorporation. The relatively high vapor pressure (3.16 x 10-4 mm Hg) and the observed Henry’s 

Law Constant (6.58 x 10-3) suggest that some parent material will dissipate by diffusion into the 

atmosphere, but that the expected amount varies depending on site conditions and application 

methods. 

The metabolites of toxicological concern, terbufos sulfoxide and terbufos sulfone, are 

more mobile and substantially more persistent than parent terbufos. Terbufos sulfoxide and 

sulfone have non-linear half-lives in aerobic soil of 116 and 96 days, respectively. These 

metabolites are also mobile in all tested soils with Freundlich Kads values ranging from 0.40 to 

2.93, and may reach groundwater when terbufos is used in locations where irrigation or rain 

water moves through the soil profile to groundwater. In addition, terbufos parent and its 

metabolites may reach surface water sources as a result of runoff events. 

In the case of terbufos, EPA is concerned about the potential for parent terbufos and its 

two major degradates, terbufos sulfoxide and sulfone, to runoff to surface water sources, and the 

potential for the degradates to leach to groundwater sources. The PRZM-EXAMS model was 

used to estimate surface water concentrations, and SCI-GROW was used to estimate 

groundwater concentrations. Although some monitoring data for terbufos were available, these 

data were deemed of limited value for several reasons, including that the degradates of concern 

were typically not included as part of the analyses. 

27
 
The data inputs used in the PRZM-EXAMS model were based on results from an aerobic 

aquatic metabolism study in pond water for parent terbufos and the terbufos sulfoxide and 

sulfone degradates (MRID 44862502). EPA used these data to determine the expected 

persistence of parent terbufos and terbufos sulfoxide and sulfone in water, and the formation rate 

of terbufos sulfone from applied sulfoxide. Terbufos parent degraded with a half-life of 1.5 days 

using non-linear analysis in nonsterile pond water, and reached nondetectable levels by 7 days. 

Applied terbufos sulfoxide degraded with a half life of 68 days and declined to 50-62 percent by 

30 days (end of study). Applied terbufos sulfone degraded with a calculated half-life of 32 days 

and declined to 39-43 percent by 30 days. 

EPA did not use the results from the abiotic hydrolysis study (MRID 44862501) for 

estimating concentrations of terbufos in surface water since the aerobic metabolism data were 

deemed to be more relevant. However, for groundwater, the hydrolysis data provided useful 

information on the persistence and degradation products in the event terbufos were to reach 

groundwater sources. 

b. Field Dissipation 

The database for field dissipation is complete. The terrestrial field data submitted 

indicate that terbufos dissipated in the field with half-lives of 24 days in sandy loam in 

California, and 14-40 days in loamy and sandy loam soils in Illinois and Colorado. These halflives are comparable to findings from the aerobic soil metabolism study discussed above (halflife 27 days). Data from the open scientific literature (Felsot, et al., 1987) reported half-lives of 

11-16 days for parent terbufos and total toxic residue half-lives of 25-28 days in silt loam and 

silty clay loam soils in the field when terbufos was applied at a rate of 1.0 lb a.i./Acre. 

2. Risk to Birds and Mammals 

Terbufos presents high acute and chronic risks to non-target terrestrial wildlife species. 

This is based on a weight of evidence evaluation from laboratory and field studies and adverse 

incidents in the field, some of which were associated with misuse/misapplication. Granular 

pesticides, such as the terbufos formulations, present a unique hazard to wildlife in that the 

granules may be ingested directly by birds foraging for seed and grit at or below the soil surface. 

Birds and mammals may also ingest granules adhered to the surface of invertebrate prey, such as 

earthworms and grubs, or through ingestion of water or food sources contaminated with terbufos. 

All currently registered uses of terbufos pose acute risks of concern based on the 

Agency’s standard LOC criteria. Acute RQs for avian species ranges from 1.3 to 32.0 and for 

mammalian species from 2.2 to 327. The ranges provided reflect differences in the application 

method and rate, and size of the bird or mammal. Both acute avian and mammalian risks exceed 

the Agency’s LOC of 0.5, indicating potential risks of concern to terrestrial organisms. Acute 

RQs associated with banded applications tend to be greater than RQs calculated for other 

application methods (e.g., in-furrow) due to less efficient soil incorporation. The database to 

assess risk to birds and mammals is complete. 

28
 
3. Risk to Aquatic Species 

The Agency is concerned about potential adverse effects to nontarget aquatic species, 

based on the Agency’s aquatic LOC assessment, which is strongly supported by fish kill 

incidents associated with the use of terbufos on corn. No aquatic field studies are available. The 

basis for the Agency’s aquatic risk concern is summarized below. The database to assess risk to 

aquatic species is complete. 

a. Aquatic LOC Assessment 

Acute and chronic RQs calculated for terbufos and its degradates exceed the Agency’s 

level of concern. Acute and chronic RQs that exceed the Agency’s acute LOC of 0.5 and 

chronic LOC of 1.0, respectively, are considered to be a risk concern. The acute RQs calculated 

for terbufos and its degradates using banded applications range from 3-17 for fish, and 14-60 for 

invertebrates. The chronic RQs calculated for terbufos and its degradates using banded 

applications range from 2-8 for fish and 113-403 for invertebrates. The ranges in RQs are due to 

the different application rates and EEC values for the crops. 

The Agency’s consideration of the total toxic residue of terbufos (parent + degradates) 

raises the acute EECs and RQs by a factor of 2.5-3X, and raises the chronic EECs and RQs by a 

factor of 15 - 50X. The greater increase for the chronic results may be due to the persistence of 

the degradates. As indicated above, the surface water EECs calculated by the Agency are based 

on measurements obtained from an aerobic aquatic metabolism study on terbufos parent and the 

terbufos sulfoxide and sulfone degradates. 

Note that for application methods other than banded, the Agency’s estimated exposures 

equal zero. However, fish kills associated with other methods of application (i.e., in-furrow) on 

corn suggest that runoff can be associated with in-furrow applications to all three labeled uses, 

corn, sugarbeets, and sorghum. The PRZM-EXAMS model used by EPA to estimate 

concentrations of terbufos and its degradates in surface water may not adequately represent the 

availability of the pesticide for runoff under all conditions. 

b. Aquatic Incidents 

Terbufos is the leading cause of fish kill incidents reported to EPA for any pesticide 

applied to corn, and ranks fourth in fish kill incidents reported to EPA for any pesticide applied 

to any crop. From 1976 to present, 96 fish kill incidents involving terbufos have been reported 

to the Agency, mostly by the registrant under FIFRA 6(a)(2), adverse effects reporting 

requirements. A causal relationship between terbufos and fish kills has not been fully 

established in all of the incidents. 

The average rate of incidents is about 4 per year, although in any given year the number 

of incidents reported can fluctuate broadly. For example, 3 incidents occurred in 2000; zero 

incidents were reported for 1999, 4 in 1997, and 18 incidents were reported for 1990. The 

Agency does not consider the aquatic incidents involving terbufos to be an exhaustive 

29
 
accounting of all the incidents. The following summarizes some other key points concerning the 

incidents. Refer to the environmental assessment and addenda for additional details. 

•	 All the incidents reported to the Agency are associated with the corn use, involve 

all methods of application, and both granular formulations (Counter 15G and 

Counter CR). 

•	 About 85 percent of the incidents to date have occurred in the midwest, corn belt 

region (Iowa, Indiana, Illinois, Nebraska, Ohio). Some incidents have occurred in 

North Carolina. 

•	 Most of the incidents occurred in static water bodies (“farm ponds”) ranging in 

size from 2 to 20 acres; some occurred in canals feeding into rivers. 

• Incidents generally occurred from 2 days to 3 weeks after application. 

•	 Incidents were reported on property not owned by the applicator/farmer, in recent 

cases, and involve reports of substantial economic loss, impacts to quality of life, 

pet mortality, and concerns about health of people swimming in impacted lakes 

and ponds. 

•	 Individual incidents indicate a broad range of mortality; from 30 up to 90,000 fish 

mortalities. On average 3,600 mortalities were reported per incident based on 

data from 1976 to 1998. Nineteen incidents reported greater than 1,000 

mortalities. 

•	 51% of the incidents were defined as highly probable or probable where terbufos 

and/or its degradates were identified from water analysis of impacted surface 

water bodies or there was adequate information on the application of the 

chemical. 46% of the incidents were defined as possible where either no water 

analysis was conducted or the water was analyzed only for the parent. In many of 

these instances terbufos was the only pesticide reported as being used 

near/adjacent to the incident site. 3% of the incidents were due to misapplication. 

•	 In a limited number of cases, in the early 1990's, it appears that pasture/grass 

buffer strips or setbacks did not prevent incidents. 

• Most of the incidents appear to be associated with normal use. 

•	 In some of the incidents, rainfall was reported as occurring over a period of days 

to weeks prior to the incident. Based on the limited weather information 

provided, the Agency believes the incidents could be associated with normal 

spring rain events, as opposed to unusually severe rainfall events over a short 

period of time. 

30
 
4. Endangered Species 

The Agency has initiated three consultations with the Fish and Wildlife Service (FWS) 

on the potential effects of terbufos corn use on endangered and threatened species. To date, the 

FWS has issued two Biological Opinions. In these Opinions, the FWS found jeopardy for 13 

fish species, 25 aquatic invertebrate species, and 4 insect species. An additional 15 fish species 

and 2 aquatic invertebrate species were expected to be affected, but not jeopardized. The FWS 

also found jeopardy for one avian species due to the potential effects of reducing its aquatic food 

source. These consultations and the findings expressed in the Opinions, however, are based on 

old labels and application methods, less refined risk assessment procedures, and an older 

approach to consultation which is currently being revised through interagency collaboration. 

EPA’s current assessment of ecological risks uses both more refined methods to define 

ecological risks of pesticides and new data, such as that for spray drift. Therefore, the 

Reasonable and Prudent Measures (RPMs) in the Biological Opinion(s) may need to be 

reassessed and modified based on these new approaches. 

The Agency is currently engaged in a Proactive Conservation Review with FWS and the 

National Marine Fisheries Service under section 7(a)(1) of the Endangered Species Act. The 

objective of this review is to clarify and develop consistent processes for endangered species risk 

assessments and consultations. Subsequent to the completion of this process, the Agency will 

reassess the potential effects of terbufos use to federally listed threatened and endangered 

species. At that time, the Agency will also consider any regulatory changes recommended in the 

RED that are being implemented. Until such time as this analysis is completed, the overall 

environmental effects mitigation strategy articulated in this document and any County Specific 

Pamphlets described below which address terbufos, will serve as interim protection measures to 

reduce the likelihood that endangered and threatened species may be exposed to terbufos at 

levels of concern. 

IV. Interim Risk Management and Reregistration Decision 

A. Determination of Interim Reregistration Eligibility 

Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after submissions of 

relevant data concerning an active ingredient, whether products containing the active ingredient 

is eligible for reregistration. The Agency has previously identified and required the submission 

of the generic (i.e., an active ingredient specific) data required to support reregistration of 

products containing terbufos active ingredients. 

The Agency has completed its assessment of the occupational and ecological risks 

associated with the use of pesticides containing the active ingredient terbufos , as well as a 

terbufos-specific dietary risk assessment that has not considered the cumulative effects of 

organophosphates as a class. Based on a review of these data and public comments on the 

Agency’s assessments for the active ingredient terbufos, EPA has sufficient information on the 

human health and ecological effects of terbufos to make an interim decisions as part of the 

31
 
tolerance reassessment process under FFDCA and reregistration under FIFRA, as amended by 

FQPA. The Agency has determined that terbufos products are eligible for reregistration 

provided that: (i) current data gaps and additional data needs are addressed; (ii) the risk 

mitigation measures outlined in this document are adopted, and label amendments are made to 

reflect these measures; and (iii) cumulative risks considered for the organophosphates support a 

final reregistration eligibility decision. Label changes are described in Section IV. Appendix B 

identifies the generic data requirements that the Agency reviewed as part of its interim 

determination of reregistration eligibility of terbufos, and lists the submitted studies that the 

Agency found acceptable. 

Although the Agency has not yet considered cumulative risks for the organophosphates, 

the Agency is issuing this interim assessment now in order to identify risk reduction measures 

that are necessary to support the continued use of terbufos. Based on its current evaluation of 

terbufos alone, the Agency has determined that terbufos products, unless labeled and used as 

specified in this document, would present risks inconsistent with FIFRA. Accordingly, should a 

registrant fail to implement any of the risk mitigation measures identified in this document, the 

Agency may take regulatory action to address the risk concerns from use of terbufos. 

At the time that a cumulative assessment is conducted, the Agency will address any 

outstanding risk concerns. For terbufos, if all changes outlined in this document are incorporated 

into the labels, then all current risks will be adequately managed. But, because this is an interim 

RED, the Agency may take further actions, if warranted, to finalize the reregistration eligibility 

decision for terbufos after assessing the cumulative risk of the organophosphate class. Such an 

incremental approach to the reregistration process is consistent with the Agency’s goal of 

improving the transparency of the reregistration and tolerance reassessment processes. By 

evaluating each organophosphate in turn and identifying appropriate risk mitigation measures, 

the Agency is addressing the risks from the organophosphates in as timely a manner as possible. 

Because the Agency has not yet considered cumulative risks for the organophosphates, 

this reregistration eligibility decision does not fully satisfy the reassessment of the existing 

terbufos food residue tolerances as called for by the Food Quality Protection Act (FQPA). When 

the Agency has considered cumulative risks, terbufos tolerances will be reassessed in that light. 

At that time, the Agency will reassess terbufos along with the other organophosphate pesticides 

to complete the FQPA requirements and make a final reregistration determination. By 

publishing this interim decision on reregistration eligibility and requesting mitigation now for 

the individual chemical terbufos, the Agency is not deferring or postponing FQPA requirements; 

rather, EPA is taking steps to assure that uses which exceed FIFRA’s unreasonable risk standard 

do not remain on the label indefinitely, pending completion of assessment required under the 

FQPA. This decision does not preclude the Agency from making further FQPA determinations 

and tolerance-related rulemakings that may be required on this pesticide or any other in the 

future. 

If the Agency determines, before finalization of the RED, that any of the determinations 

described in this interim RED are no longer appropriate, the Agency will pursue appropriate 

action, including but not limited to, reconsideration of any portion of this interim RED. 

32
 
B. Summary of Phase 5 Comments and Responses 

When making its interim reregistration decision, the Agency took into account all 

comments received during Phase 5 of the OP Pilot Process. These comments in their entirety are 

available in the docket. The Agency received comments and a risk mitigation proposal from the 

registrant, BASF Corporation. The International Banana Association also sent comments on the 

risk assessment and USDA commented on ecological risks of terbufos. The Agency also 

received 113 comments from various agri-business companies and associations, commodity 

companies, farm bureaus, universities, extension, and state agencies, as well as private citizens, 

supporting the use of terbufos. Comments opposing the use of terbufos were received from the 

Defenders of Wildlife and a private citizen. The Agency also received six comments on fish kill 

incidents attributed to terbufos. 

BASF Corporation submitted various comments pertaining to the Occupational and 

Residential Revised Risk Assessment. Some of the comments are included below and a 

complete response to the comments can be found in the public docket. 

Comment 

BASF found acceptable MOE’s in their worker exposure studies with Counter 20C. This 

differs from the Agency’s assessment. 

Response 

The Agency does not concur with BASF’s findings and states that if is not clear from the 

registrants letter what input values were used to calculate the risk values. 

Comment 

BASF objected to the Agency’s use of surrogate Pesticide Handlers Exposure Database 

(PHED) data instead of available high quality product specific exposure data. 

Response 

The Agency does not concur with this comment. The Agency did use chemical specific 

data from studies completed by American Cyanamid where appropriate and used PHED data in 

cases where there was a lack of chemical-specific data to calculate risks. 

Comment 

BASF objects to the Agency’s failure to use the enclosed cab tractors with open windows 

scenario as an appropriate surrogate for open cab tractors. 

Response 

Review of the data shows that dermal exposure in the closed cab with open windows 

scenario is two orders of magnitude less than PHED exposures with open cabs. Therefore, the 

Agency feels closed cab tractors with open windows is more analogous to closed cabs than open 

cab tractors. This data was used to assess worker risk for enclosed cab scenarios. 

Comment 

33
 
BASF states that the EPA used 180 acres per day for corn in the chlorethoxyfos 

assessment, a chemical with the same use pattern as terbufos. In addition, 180 acres is an 

appropriate maximum estimate given that it is likely that the exposure is shared by two people an 

average of 20% of the time. 

Response 

The Agency has used the acreage estimates from the corn cluster analysis for several 

years and cannot substantiate why a different value was used for chlorethoxyfos. However, 180 

acres was included in the Occupational and Residential Exposure chapter to allow for a more 

informed risk management decision. 

The International Banana Association (IBA) also sent a comment pertaining to the 

Agency’s use assumptions for terbufos in bananas. Some of the comments are included below 

and a complete response to the comments can be found in the public docket. 

Comment 

The IBA calculated that 10.9% of a banana crop is treated with terbufos whereas the 

Agency calculated the figure to be 26%. 

Response 

The Agency has reviewed the IBA proposal and concluded that this is not a valid 

approach for assessing percent crop treated. The dietary risk from food was not a concern for 

terbufos even with the 26% figure. 

C. Regulatory Position 

1. FQPA Assessment 

a. “Risk Cup” Determination 

As part of the FQPA tolerance reassessment process, EPA assessed the risks associated 

with this organophosphate. The assessment is for this individual organophosphate, and does not 

attempt to fully reassess these tolerances as required under FQPA. FQPA requires the Agency to 

evaluate food tolerances on the basis of cumulative risk from substances sharing a common 

mechanism of toxicity, such as the toxicity expressed by the organophosphates through a 

common biochemical interaction with the cholinesterase enzyme. The Agency will evaluate the 

cumulative risk posed by the entire class of organophosphates once the methodology is 

developed and the policy concerning cumulative assessments is resolved. 

EPA has determined that risk from exposure to terbufos is within its own “risk cup.” In 

other words, if terbufos did not share a common mechanism of toxicity with other chemicals, 

EPA would be able to conclude today that the tolerances for terbufos meet the FQPA safety 

standards. In reaching this determination EPA has considered the available information on the 

special sensitivity of infants and children, as well as the chronic and acute food exposure. An 

aggregate assessment was conducted for exposures through food, residential uses, and drinking 

34
 
water. Results of this aggregate assessment indicate that the human health risks from these 

combined exposures are considered to be within acceptable levels; that is, combined risks from 

all exposures to terbufos “fit” within the individual risk cup. Therefore, with the exception of 

corn, pop fodder, the terbufos tolerances remain in effect and unchanged until a full reassessment 

of the cumulative risk from all organophosphates is considered. The tolerance for corn, pop, 

fodder, has been revoked because it is no longer a significant food item. 

b. Tolerance Summary 

In the individual assessment, tolerances for residues of terbufos in/on plant commodities 

[40 CFR §180.352] are presently expressed in terms of the combined residues of terbufos [(S­

((1, 1-dimethyl)thio)methyl) O, O-diethyl phosphorodithioate] and its cholinesterase-inhibiting 

metabolites [40 CFR §180.352(a)]. The Agency concludes that the tolerance expression should 

be stated in terms of " ...terbufos...and its phosphorylated (cholinesterase-inhibiting) metabolites: 

• phosphorothioic acid, S-(t-butylthio)methyl O,.O-diethyl ester; 

• phosphorothioic acid, S-(t-butylsulfinyl)methyl O,.O-diethyl ester; 

• phosphorothioic acid, S-(t-butylsulfonyl)methyl O,.O-diethyl ester; 

• phosphorodithioic acid, S-(t-butylsulfinyl)methyl O,.O-diethyl ester; 

• phosphorodithioic acid, S-(t-butylsulfonyl)methyl O,.O-diethyl ester; 

The chemical name for terbufos specified in 40 CFR §180.352(a) is incorrect, and should be 

revised to read as "phosphorodithioic acid, S-(t-butylthio)methyl O, O-diethyl ester." 

Tolerances Listed Under 40 CFR §180.352(a): 

The tolerances listed in 40 CFR §180.352(a) are for residues of terbufos and its 

cholinesterase-inhibiting metabolites. Please note that several of the commodity definitions will 

need to corrected to conform with current definitions. 

Sufficient data are available to ascertain the adequacy of the established tolerances listed 

in 40 CFR §180.352(a) for: bananas, beets, sugar, roots; beets, sugar, tops; corn, field, fodder; 

corn, field, forage; corn, pop, fodder; corn, pop, forage; corn, grain; corn, sweet, (K+CWHR); 

corn, sweet, forage; corn, sweet, fodder; sorghum, fodder, sorghum, forage, and sorghum, grain. 

Certain commodity definitions of the above tolerances are not in accordance with the current 

definitions and therefore need to be updated. 

An adequate method is available for data collection and enforcement of terbufos 

tolerances in or on plant commodities. The GLC/flame ionization-detection method for 

determining terbufos and its phosphorylated metabolites is described in PAM, Vol. II, as Method 

I. The hazardous reagent benzene is specified in this method. 

Method M-1754, a modification of Method I in PAM that substitutes acetone for benzene 

and methylene chloride for chloroform, underwent a successful Residue Analytical Laboratory 

method validation trial and was forwarded to FDA for revision of PAM, Vol II. 

35
 
 Table 8a. Tolerance Summary for Terbufos. 

Commodity Current Tolerance, 

ppm 

Tolerance 

Reassessment*, ppm 

Comment/ 

[Correct Commodity Definition] 

Tolerances Listed Under 40 CFR §352 

Bananas 0.025 0.025 Banana 

Beets, sugar, roots 0.05(N) 0.05 

The negligible residue residue (N) 

should be deleted. 

beet, sugar, roots 

Beets, sugar tops 0.1 0.1 beet, sugar, tops 

Corn, field, fodder 0.5 0.5 corn, field, stover 

Corn, field, forage 0.5 0.5 NA 

Corn, pop, fodder 0.5 0.5 corn, pop, stover 

Corn, pop forage 0.5 revoke NA 

Corn, grain 0.05(N) 0.05 

The tolerance for “Corn, grain” 

should be replaced with separate 

tolerances for corn, field, grain 

and Corn, pop, grain. The 

negligible residue residue (N) 

should be deleted 

Corn, sweet (K=CWHR) 0.05(N) 0.05 

corn, sweet, kernel plus cob with 

husks removed 

The negligible residue residue (N) 

should be deleted 

Corn, sweet, forage 0.5 0.5 NA 

Corn, sweet, fodder 0.5 0.5 corn, sweet, stover 

Sorghum, fodder 0.5 0.5 sorghum, grain, stover 

Sorghum, forage 0.5 0.5 sorghum, grain, forage 

Sorghum, grain 0.05 0.05 sorghum, grain, grain 

* The term “reassessed” here is not meant to imply that the tolerance has been reassessed as required by FQPA, since this tolerance may 

be reassessed only upon completion of the cumulative risk assessment of all organophosphates, as required by this law. Rather, it 

provides a tolerance level for this single chemical, if no cumulative assessment was required, that is supported by all of the submitted 

residue data. 

Codex Maximum Residue Limits (MRLs) for the sum of terbufos, its oxygen analog and 

their sulfoxides and sulfones, expressed as terbufos, have been established for a number of plant 

and animal commodities. The Codex definition is compatible with the recommended revision to 

the U.S. Tolerance definition, which specifically names terbufos, its oxygen analog, and their 

sulfoxides and sulfones. 

36
 
No questions of compatibility exist with respect to commodities where: (i) no Codex 

MRLs have been established but U.S. Tolerances exist; and (ii) Codex MRLs have been 

established but U.S. Tolerances do not exist. Tolerances in such commodities as maize (corn), 

popcorn, and sweet corn cannot currently be harmonized with CODEX tolerances; although both 

U.S. and Codex tolerances in these commodities are based on the limit of detection (LOD), the 

LOD under the CODEX system is 0.01 ppm, while the LOD under the U.S. system is 0.05 ppm. 

Table 8b. Codex MRLs and Applicable U.S. Tolerances. 

Commodity MRL (Step) (mg/kg) Reassessed U.S. 

Tolerance (ppm) Codex definition Reassessed U.S. 

definition 

Fodder beet leaves or 

tops 

beet, sugar, tops 1 (5/8) 0.1 

Maize corn, field, grain 0.01 (5/8) 0.05 

Maize forage corn, field, forage 1 (5/8) 0.5 

Popcorn corn, pop, grain 0.01 (5/8) 0.05 

Straw and fodder (dry) 

of cereal grains 

corn, field, stover 

corn, pop, stover 

corn, sweet, stover 

sorghum, grain, stover 

1 (5) 0.5 

0.5 

0.5 

1 

Sugar beet beet, sugar, roots 0.1 (5) 0.05 

Sweet corn (corn-onthe-cob) corn, sweet, kernel plus 

cob with husks removed 

0.01 (5) 0.05 

2. Endocrine Disruptor Effects 

EPA is required under the FFDCA, as amended by FQPA, to develop a screening program 

to determine whether certain substances (including all pesticide active and other ingredients) 

"may have an effect in humans that is similar to an effect produced by a naturally occurring 

estrogen, or other such endocrine effects as the Administrator may designate." Following the 

recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee 

(EDSTAC), EPA determined that there was scientific bases for including, as part of the program, 

the androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA 

also adopted EDSTAC’s recommendation that the Program include evaluations of potential 

effects in wildlife. For pesticide chemicals, EPA will use FIFRA and, to the extent that effects in 

wildlife may help determine whether a substance may have an effect in humans, FFDCA 

authority to require the wildlife evaluations. As the science develops and resources allow, 

screening of additional hormone systems may be added to the Endocrine Disruptor Screening 

Program (EDSP). 

37
 
When the appropriate screening and/or testing protocols being considered under the 

Agency’s EDSP have been developed, terbufos may be subjected to additional screening and/or 

testing to better characterize effects related to endocrine disruption. 

3. Labels 

A number of label amendments, in addition to the existing label requirements, are 

necessary in order for terbufos products to be eligible for reregistration. The Agency has 

determined that these measures, in addition to the existing label requirements, will adequately 

reduce risks to handlers. 

Provided the following risk management measures are incorporated in their entirety into 

labels for terbufos-containing products, the Agency finds that all currently registered uses of 

terbufos are eligible for interim reregistration, pending consideration of cumulative risks of the 

organophosphates. The regulatory rationale for each of the risk management measures outlined 

below is discussed immediately after this list of required risk management measures. 

a. Agricultural Use Exposure Reduction Measures 

For agricultural use, the following measures are required, in addition to the existing 

labeling requirements to address drinking water, occupational handler and ecological risks of 

concern. The registrant has agreed to these measures. 

•	 Amend the North Carolina SLN registration of Counter 20CR to require the use of a 

closed loading system. 

•	 Require that the Counter 15G label be amended to indicate that applications must be 

made using enclosed cab tractors. 

•	 Reduce the application rate on sorghum from 1.96 lbs. a.i. per acre to 1.70 lbs. a.i. 

per acre. 

•	 Require a 500 ft. vegetative buffer between treated area and surface water on 

neighboring land 

•	 Require a 500 ft. vegetative buffer between a standpipe drain outlet and surface 

water on neighboring land. 

•	 Require a 66 ft. setback between the treated area and entry points to surface water 

bodies on non-highly erodible soils 

•	 Require a 300 foot setback between the treated area and entry points to surface water 

bodies on highly erodible soils. 

•	 Require a 66 ft. setback between treated area and standpipes on terraced fields as 

well as 66 ft. vegetative buffer between the tile outlet and surface water bodies 

•	 Restrict loading, rinsing, and washing equipment within 300 ft. from surface water 

bodies or within 50 ft. from wells unless conducted on an impervious surface. 

• Remove the “over the top” application for European corn borer control on corn. 

•	 Require placing granules for banded applications on corn in a 7 inch band over the 

row, in front of the press wheel, and incorporated into the top 1 inch of soil. 

38
 
•	 To prevent the flow of rainfall down planted rows, the label text will be required to 

read “To prevent channeling of surface water run-off, adjust the planter row-cleaners 

appropriately to prevent rows lower in height than adjacent soil”. 

b. Homeowner Use Exposure Reduction Measures 

There are no residential uses for terbufos. 

D. Regulatory Rationale 

The following is a summary of the rationale for managing risks associated with the use of 

terbufos. Where labeling revisions are imposed, specific language is set forth in the summary 

tables of Section V of this document. 

1. Human Health Risk Mitigation 

a. Dietary Mitigation 

1) Acute Dietary (Food) 

Acute dietary risk from food is below the Agency’s level of concern – less than 100% of 

the acute PAD is used. For the most exposed subgroups, non-nursing infants and infants (< 1 

year), the percent acute PAD values are 86% and 82%, respectively, at the 99.9th percentile of 

exposure from consumption of food alone. No mitigation measures are necessary at this time to 

address acute dietary risk from food. Dietary risk from food consumption is estimated using 

anticipated residues from field trial data rather than residues from monitoring data. Anticipated 

residues are generally considered to be more conservative than monitoring data in terms of 

residue levels that consumers are exposed to in their diet. They represent maximum allowed 

treatment parameters and do not account for any reduction in pesticide residue levels that may 

occur from the time the crop is harvested until it is consumed. Additionally, the exposures are 

based largely on residue values from field trial data below the limit of detection (LOD), between 

the LOD and limit of quantitation (LOQ), or at the LOQ for which the Agency assumed residues 

to be one half of the LOD. It should be noted that the available PDP monitoring data, while not 

appropriate for the purposes of quantitative risk assessment, showed no detections of terbufos or 

terbufos sulfone residues in over 100 samples of sweet corn. This suggests that the acute dietary 

assessment is based on conservative exposure values that likely overstate risk. 

2) Chronic Dietary (Food) 

Chronic dietary risk from food alone is well below the Agency’s level of concern. For the 

most exposed subgroups, infants, the percent chronic PAD values are 9% or less. No mitigation 

measures are necessary at this time to address chronic dietary risk from food. 

3) Drinking Water 

39
 
The acute and chronic dietary risks from drinking water exposure are above the Agency’s 

level of concern for most subpopulations. However, there are uncertainties which lead the 

Agency to expect that exposure from drinking water is unlikely to be as high as the levels used in 

the development of the risk assessment. Based on these uncertainties and the anticipated impacts 

on water resources from implementing the risk reduction measures contained in this document, 

the Agency believes that the risks from drinking water are not of concern. 

The drinking water risk assessments are based on screening level models that are 

conservative in their estimates of drinking water exposure. Actual exposure is expected to be 

lower than the EEC’s reported in the IRED. An example of the type of assumptions used in the 

model that can contribute to conservative estimates involves rainfall levels. To determine what 

rainfall level to use in the model, the Agency identifies a peak rainfall level for each of 36 years 

of daily rainfall data. The model then assumes that rainfall will equal the 90th percentile of these 

36 annual peak values when estimating concentrations, a conservative assumption. Also, the 

percent cropped area (PCA) assumption for sugar beets and sorghum used in the model is 0.87, 

the default assumption. This means the model assumes that 87% of a watershed is planted with 

one of these crops and that 100% of this crop is treated with terbufos, which appears unlikely to 

occur especially considering that the PCA calculated for a major crop like corn using data 

submitted to the Agency is 0.46. 

Further, although the available NAWQA monitoring data were deemed insufficient for the 

purpose of quantitative risk assessment primarily due to the failure to include metabolites of 

terbufos, these data yielded surface water concentrations that were lower than the results of the 

model. These levels ranged from 0.013 ppb to 0.56 ppb as compared to the model estimate for 

parent terbufos of 9.39 ppm. 

To provide additional perspective, it should also be noted that the maximum ground water 

and surface water EEC’s result from modeling terbufos use on sorghum. According to sales 

figures for 2000 provided by the registrant, sorghum accounts for approximately 1% of total 

terbufos use. The acute EEC’s for corn which accounts for 90% of terbufos use are significantly 

lower at 4.8 ppb (ground water) and 8.44 (surface water). 

In addition, as explained earlier, the DWLOC is calculated based on dietary risk from food 

consumption that is estimated using conservative exposure estimates (i.e. anticipated residues 

from field trials, etc.). Therefore, the Agency expects that the actual exposure from food is 

lower, which would result in additional space in the risk cup for residues in drinking water. 

The risk reduction measures contained in this IRED, including the limitations on sales of 

terbufos, reducing the maximum application rate for sorghum, increasing the depth of 

incorporation of granules into the soil, removal of “over-the-top” applications, and the use of 

vegetative buffer strips between treated field and water bodies and other areas where water 

contamination could occur, particularly the use of a 500 foot buffer between a treated area and 

water resources on nearby lands which would include such things as reservoirs, are expected to 

provide improved protection of water resources from terbufos contamination. This supports the 

Agency’s belief that drinking water risks will be reduced to a level at which the risk cup is not 

exceeded. 

40
 
Finally, the Agency is requiring surface and ground water monitoring data to confirm the 

Agency’s conclusions on dietary risks from drinking water. The Agency notes that drinking 

water monitoring studies are either planned or underway which will inform the Agency 

regarding its conclusions on levels of terbufos and its metabolites in drinking water. One of 

these studies is related to the Unregulated Contaminant Monitoring Rule under which the EPA is 

considering whether or not to set a drinking water standard for terbufos under the Safe Drinking 

Water Act. This study is monitoring the levels of chemicals, including terbufos, in over 300 

drinking water plants across the United States. The other study is being sponsored by the 

American Crop Protection Association which will also monitor drinking water for pesticide 

residues. In order for these studies to be used the Agency will need to confirm that samples were 

taken from areas of terbufos use and during the time period when terbufos is used. Further, 

monitoring for the important degradates of terbufos, terbufos sulfoxide and terbufis sulfone, will 

need to be addressed. 

b. Occupational Risk Mitigation 

1) Agricultural Uses 

EPA has risk concerns for occupational exposure scenarios assessed for the Counter 15G 

product, even when used in a manner consistent with the engineering control parameters from 

the occupational study. This assumes both use of a closed mixing and loading system (currently 

on labels) and enclosed cabs for application (not a current label requirement) . Specifically, 

handlers have risks of concern when loading Counter 15G at the 2x North Carolina SLN rate on 

corn and loading for sugar beets and sorghum at the maximum labeled rate (1.97 lbs ai/acre) and 

maximum acreage treated per day assumption of 213 acres. In addition, there are risks of 

concern when applying Counter 15G in open cabs (maximum PPE) using the maximum 

rate/acreage on corn, the North Carolina SLN 2x rate on corn, the maximum rate/acreage on 

sugar beets, and the maximum rate/acreage on sorghum. The Agency also has risk concerns for 

the scenario for 15G where application is made without a enclosed cab. 

For application of Counter 15G, applicator risks are of concern at maximum PPE with 

MOEs ranging from 2.7-5.3. When an enclosed cab is used the MOEs range from 157-208 and 

are not of concern. 

For loading of Counter 15G at the 2x North Carolina SLN rate on corn, the MOE is 53, a 

value below the target MOE of 100. This value is based on a maximum acreage treated/day of 

213 acres. However, based on survey data from North Carolina, the Agency has determined the 

typical acreage treated per day to be 150 acres. The analysis conducted using this acreage 

assumption results in a MOE of 75. In addition, the Agency’s benefits assessment determined 

there are currently no effective alternatives to terbufos for controlling billbugs in North Carolina 

fields with high organic matter soil. Therefore, considering that engineering controls are in place 

for this activity and there are significant benefits associated with this use, the Agency concludes 

that no additional exposure reduction is warranted. 

The MOEs for loading Counter 15G on sugar beets at the maximum rate (1.97 lbs ai/acre) 

and acreage (213 acres) is also below the target MOE of 100. However, based on a survey the 

41
 
Agency determined the acreage treated per day to be 130 acres for sugar beets. The analysis 

conducted using this acreage assumption results in an acceptable MOE of 114. 

The MOEs for loading Counter 15G on sorghum at the maximum rate (1.97 lbs ai/acre) 

and acreage (213 acres) is below the target MOE of 100. The registrant has agreed to reduce the 

maximum application rate to 1.7 lbs ai/acre which would result in a MOE of 81. This does not 

reach the target MOE of 100, however, it is believed that reducing the rate further would reduce 

the chemical’s efficacy against sorghum pests. The primary alternative to terbufos, aldicarb, is 

expensive compared to terbufos and the Agency has determined that choosing this alternative 

would reduce the growers net revenues by as much as 78% if used. In addition, other 

alternatives are not as efficacious in controlling wireworms, a pest of sorghum. Therefore, based 

on the benefits of terbufos use on sorghum, the Agency concludes that no additional exposure 

reduction is warranted. 

For the Counter 20CR product, the Agency has some risk concerns when the product is 

handled in open bags. Specifically, the Agency is concerned about risks to agricultural workers 

handling Counter CR in open bags under the Special Local Need (SLN) registration in North 

Carolina and loading for sugar beets and sorghum. There are no risk concerns when Counter CR 

is handled in closed systems (Lock-N-Load) and open or enclosed cabs. 

The MOE for handling Counter 20CR in open bags under the Special Local Need (SLN) 

registration, which permits terbufos use on corn at twice the labeled maximum application rate, 

is 64. This risk concern can be mitigated if the SLN registration is amended to require the use of 

closed loading systems. The North Carolina Department of Agriculture and Consumer Services, 

the department responsible for managing state registrations, and the registrant have agreed to 

amend the SLN registration to make this a requirement on the label. 

The MOEs for loading Counter 20CR in open bags on sugar beets at the maximum rate 

(1.97 lbs ai/acre) and acreage (213 acres) are below the target MOE of 100. As with the Counter 

15G product, a survey of acreage treated per day determined the maximum to be 130 acres for 

sugar beets which results in an acceptable MOE of 140. 

The MOEs for loading Counter 20 CR in open bags on sorghum at the maximum rate (1.97 

lbs ai/acre) and acreage (213 acres) are also below the target MOE of 100. BASF has agreed to 

reduce the maximum rate to 1.7 lbs ai/acre which gives a MOE of 98. 

Table 11 describes the necessary PPE and engineering controls to mitigate worker risks. 

Table 9. Agricultural Uses: Handler Risk Concerns and Mitigation 

Scenario PPE Engineering 

Controls 

Loading granular in lock-n-load 

containers (15G and 20 CR 

formulation) 

long-sleeved shirt and long pants, shoes plus 

socks chemical-resistant gloves and chemicalresistant apron 

lock-n-load 

container 

42
 
Loading granular in open bags (20 

CR formulation) 

coveralls over long-sleeved shirt and long pants, 

chemical-resistant apron, chemical resistant 

gloves, chemical resistant footwear plus socks, 

and OV respirator 

none 

Applying 15G granular formulation long-sleeved shirt and long pants, shoes plus 

socks 

enclosed cab 

Applying 20 CR granular formulation coveralls over long-sleeved shirt and long pants, 

chemical resistant gloves, chemical resistant 

footwear plus socks 

none 

2) Post-Application Risk 

There is a low potential for occupational post-application exposure when pre-emergent 

insecticides are used. Terbufos is applied to the soil directly and is soil incorporated well before 

the crops are mature. The timing of the application of terbufos can greatly reduce the potential 

for post-application exposure. Also, most agricultural operations mechanically plant corn early 

in the season, which minimizes the potential for dermal contact. Minimal exposure during 

harvesting or any other late season activities is expected since terbufos is primarily applied preemergent. Therefore, the Agency does not require a post-application occupational exposure 

assessment (HED Exposure Science Advisory Council Policy No. 008). The REI for crops 

treated with terbufos is 48 hours and 72 hours in areas where average annual rainfall is less than 

25 inches per years. Early entry PPE for crops treated with terbufos is: coveralls worn over 

long-sleeve shirt and long pants, chemical-resistant gloves made of any waterproof material, 

chemical-resistant footwear plus socks, and protective eyewear. 

c. Homeowner Risk Mitigation 

Terbufos is not registered for use in residential settings. 

2. Environmental Risk Mitigation 

The Agency has determined that these risks can be reduced to an acceptable level taking 

into consideration the benefits by a reducing the total amount of terbufos that can be applied 

through imposing an annual sales cap and buffers. The registrant has agreed to a phased 

approach that will ultimately reduce sales of terbufos by more than 55% by 2008 based on 2000 

sales figures. By reducing the amount of terbufos applied in this way the Agency expects that 

risks to aquatic and terrestrial organisms will be reduced. 

The buffers to be implemented are; 1) a 500 ft. vegetative buffer between treated area and 

surface water on neighboring land, 2) a 500 ft. vegetative buffer between a standpipe drain outlet 

and surface water on neighboring land, 3) a 300 ft. setback between the treated area and entry 

points to surface water bodies on highly erodible soils and 66 ft. on non-highly erodible soils, 4) 

a 66 ft. setback between treated area and standpipes on terraced fields as well as 66 ft. vegetative 

buffer between the tile outlet and surface water bodies, and 5) restricting loading, rinsing, and 

washing equipment within 300 ft. from surface water bodies or within 50 ft. from wells unless 

43
 
conducted on an impervious surface. All setbacks must be planted to a crop or seeded with grass 

or other suitable cover. Erosion potential of soils can be determined by consulting with the 

National Resource Conservation Service (NRCS). 

In addition, the registrant has agreed to remove from its labels the “over the top” 

application on corn for european corn borer control. Banded applications on corn will also 

require placing granules in a 7 inch band over the row, in front of the press wheel, and 

incorporated into the soil to a depth of 1 inch. To prevent the flow of rainfall down planted 

rows, the label text will read “To prevent channeling of surface water run-off, adjust the planter 

row-cleaners appropriately to prevent rows lower in height than adjacent soil”. 

The Agency believes that the buffers and other changes in application methods described 

above will reduce the likelihood that terbufos will contaminate surface water. In so doing, nontarget aquatic organisms, especially fish, would be less likely to be exposed to terbufos or its 

metabolites. 

The registrant has also committed to voluntarily remove use from counties where multiple, 

verifiable fish kills occur in that county over a period of two or more years as the result of the 

use of terbufos in accordance with the risk management measures set forth in this document. 

The registrant will conduct product stewardship and educational efforts in counties where an 

incident occurs to address the cause of the incident and seek to prevent a second incident which 

would result in the discontinuation of use in that county. 

3. Benefits Assessment 

Both the preliminary and the revised human health and ecological risk assessments 

identified risks of concern for occupational handlers and terrestrial and aquatic non-target 

organisms. Since risks of concern in these areas are regulated under FIFRA’s requirement that 

the Agency consider the risks and benefits of pesticide use in making its regulatory decision, the 

Agency has conducted a benefits assessment for use in determining the appropriate risk 

management steps to be taken to address these risks. This assessment was aimed at quantifying, 

to the extent possible, the benefits derived from the use of terbufos on corn primarily for control 

of corn rootworm. 

The benefits of terbufos on corn were estimated using a comparative product performance 

assessment (BEAD Memo-Product Performance Assessment Methodology as Applied to 

Terbufos Use on Field Corn, 12/15/2000). This assessment relied on data from numerous 

product performance studies available in the open scientific literature. These data were analyzed 

using statistical methods to determine the relative effects on corn yields of using terbufos and 

other corn insecticides especially tefluthrin. The benefits assessment concluded that under most 

conditions the alternative insecticides produced similar or greater yields than fields where 

terbufos was used. Terbufos did show an advantage over the alternatives in controlling billbugs 

in North Carolina and controlling corn rootworm in the Northeast. Terbufos also performed 

more effectively on some secondary corn pests. However, there are uncertainties associated with 

the assessment that were taken into consideration when developing the risk management 

measures. 

44
 
The benefits assessment was reviewed by several independent external experts and the 

United States Department of Agriculture. The registrant was also provided a courtesy copy. The 

university researchers who provided an independent peer review of the assessment to the Agency 

noted, in some instances, limitations or uncertainties that are associated with the assessment. 

These include the use of yields versus root ratings in determining benefits, the use of small plot 

studies to extrapolate to larger fields, and limitations of the statistical methods used to compare 

and analyze the available data sets. 

The Agency considered the results of the benefits assessment together with the 

uncertainties present in the analysis when developing its risk reduction measures to address 

occupational and ecological risks especially with regard to determining the appropriate level for 

the sales limits considered to be a key aspect of risk management. 

E. Other Labeling 

In order to remain eligible for reregistration, other use and safety information need to be 

placed on the labeling of all end-use products containing terbufos. For the specific labeling 

statements, refer to Section V of this document 

1. Endangered Species Statement 

The Agency has developed the Endangered Species Protection Program to identify 

pesticides whose use may cause adverse impacts on endangered and threatened species, and to 

implement mitigation measures that address these impacts. The Endangered Species Act 

requires federal agencies to ensure that their actions are not likely to jeopardize listed species or 

adversely modify designated critical habitat. To analyze the potential of registered pesticide 

uses to affect any particular species, EPA puts basic toxicity and exposure data developed for 

REDs into context for individual listed species and their locations by evaluating important 

ecological parameters, pesticide use information, the geographic relationship between specific 

pesticides uses and species locations, and biological requirements and behavioral aspects of the 

particular species. This analysis will take into consideration any regulatory changes 

recommended in this RED that are being implemented at that time. A determination that there is 

a likelihood of potential impact to a listed species may result in limitations on use of the 

pesticide, other measures to mitigate any potential impact, or consultations with the Fish and 

Wildlife Service and/or the National Marine Fisheries Service as necessary. 

The Endangered Species Protection Program as described in a Federal Register notice (54 

FR 27984-28008, July 3, 1989) is currently being implemented on an interim basis As part of 

the interim program, the Agency has developed County Specific Pamphlets that articulate many 

of the specific measures outlined in the Biological Opinions issued to date. These Pamphlets are 

available for voluntary use by pesticide applicators, on EPA’s web site at www.EPA.gov/espp . 

A final Endangered Species Protection Program, which may be altered from the interim program, 

is scheduled to be proposed for public comment in the Federal Register before the end of 2001. 

V. What Registrants Needs to Do 

45
 
In order to be eligible for reregistration, registrants need to implement the risk mitigation 

measures outlined in Section IV and V, which include, among other things, submission of the 

following: 

A. For terbufos technical grade active ingredient products, registrants need 

to submit the following items. 

Within 90 days from receipt of the generic data call-in (DCI): 

(1) 	 completed response forms to the generic DCI (i.e., DCI response form and 

requirements status and registrant’s response form); and 

(2) 	 submit any time extension and/or waiver requests with a full written 

justification. 

Within the time limit specified in the generic DCI: 

(1)	 Cite any existing generic data which address data requirements or submit 

new generic data responding to the DCI. 

Please contact Eric R. Olson at (703) 308-8067 with questions regarding generic 

reregistration and/or the DCI. All materials submitted in response to the generic DCI should be 

addressed: 

46
 
By US mail:
 By express or courier service:
 

Document Processing Desk (DCI/SRRD)
 Document Processing Desk (DCI/SRRD)
 

Eric R. Olson
 Eric R.Olson
 

US EPA (7508C)
 Office of Pesticide Programs (7508C)
 

1200 Pennsylvania Ave., NW
 Room 266A, Crystal Mall 2
 

Washington, DC 20460
 1921 Jefferson Davis Highway
 

Arlington, VA 22202 
 

B. For products containing the active ingredient terbufos, registrants need to 

submit the following items for each product. 

Within 90 days from the receipt of the product-specific data call-in 

(PDCI): 

(1)	 completed response forms to the PDCI (i.e., PDCI response form and 

requirements status and registrant’s response form); and 

(2)	 submit any time extension or waiver requests with a full written 

justification. 

Within eight months from the receipt of the PDCI: 

(1) two copies of the confidential statement of formula (EPA Form 8570-4); 

(2)	 a completed original application for reregistration (EPA Form 8570-1). 

Indicate on the form that it is an “application for reregistration”; 

(3)	 five copies of the draft label incorporating all label amendments outlined 

in Table 12 of this document; 

(4)	 a completed form certifying compliance with data compensation 

requirements (EPA Form 8570-34); 

(5)	 if applicable, a completed form certifying compliance with cost share 

offer 

requirements (EPA Form 8570-32); and 

(6) the product-specific data responding to the PDCI. 

Please contact Karen Jones at (703) 308-8047 with questions regarding product 

reregistration and/or the PDCI. All materials submitted in response to the PDCI should be 

addressed: 

By US mail: By express or courier service only: 

Document Processing Desk (PDCI/PRB) Document Processing Desk(PDCI/PRB) 

47
 
Karen Jones Karen Jones
 

US EPA (7508C) Office of Pesticide Programs(7508C)
 

1200 Pennsylvania Ave., NW Room 266A, Crystal Mall 2
 

Washington, DC 20460 1921 Jefferson Davis Highway
 

Arlington, VA 22202 

A. Manufacturing Use Products 

1. Additional Generic Data Requirements 

The generic data base supporting the reregistration of terbufos for the above eligible uses 

has been reviewed and determined to be substantially complete. The following data gaps 

remain: 

•	 Drinking water monitoring data for both surface and groundwater sources for 

terbufos and metabolite levels in corn, sorghum, and sugar beet growing regions. 

This data is requested in order to confirm that the levels of these compounds are 

lower than predicted in the Agency’s water models (OPPTS 167-1-SS). 

•	 Neurotoxic esterase (NTE) data on the hen to support the hen delayed neurotoxicity 

study. (OPPTS 870.6100) 

Also, a Data Call-In Notice (DCI) was recently sent to registrants of organophosphate 

pesticides currently registered under FIFRA (August 6, 1999 64FR 42945-42947, August 18 

1999 64FR 44922-44923). DCI requirements included acute, subchronic, and developmental 

neurotoxicity studies; due dates are 9/2001. Registrant responses are under review. 

2. Labeling Requirements for Manufacturing Use Products 

To remain in compliance with FIFRA, manufacturing use product (MUP) labeling must be 

revised to comply with all current EPA regulations, PR Notices and applicable policies. The 

MUP labeling should bear the labeling contained in Table 10 at the end of this section. 

B. End-Use Products 

1. Additional Generic Data Requirements 

Section 4(g)(2)(B) of FIFRA calls for the Agency to obtain any needed product-specific 

data regarding the pesticide after a determination of eligibility has been made. Registrants must 

review previous data submissions to ensure that they meet current EPA acceptance criteria and if 

not, commit to conduct new studies. If a registrant believes that previously submitted data meet 

current testing standards, then the study MRID numbers should be cited according to the 

instructions in the Requirement Status and Registrants Response Form provided for each 

product. 

48
 
A product-specific data call-in, outlining specific data requirements, accompanies this interim 

RED. 

2. Labeling Requirements for End-Use Products 

Labeling changes are necessary to implement the mitigation measures outlined in Section 

IV above. Specific language to incorporate these changes is specified in Table 10 at the end of 

this section. 

C. Existing Stocks 

Registrants may generally distribute and sell products bearing old labels/labeling for 26 

months from the date of the issuance of this Interim Reregistration Eligibility Decision 

document. Persons other than the registrant may generally distribute or sell such products for 50 

months from the date of the issuance of this interim RED. However, existing stocks time frames 

will be established case-by-case, depending on the number of products involved, the number of 

label changes, and other factors. Refer to “Existing Stocks of Pesticide Products; Statement of 

Policy”; Federal Register, Volume 56, No. 123, June 26, 1991. 

The Agency has determined that registrant may distribute and sell terbufos products 

bearing old labels/labeling for 26 months from the date of issuance of this interim RED. Persons 

other than the registrant may distribute or sell such products for 50 months from the date of the 

issuance of this interim RED. Registrants and persons other than the registrant remain obligated 

to meet pre-existing Agency imposed label changes and existing stocks requirements applicable 

to products they sell or distribute. 

49
 
D. Required Labeling Changes Summary Table 

Table 10: Summary of Required Labeling Changes for Terbufos 

Description Required Labeling 

Manufacturing Use Products 

Formulation Instructions required on all MUP’s 

“Only for formulation into an insecticide for use on corn, sugar beets, and grain sorghum.” 

One of these statements may be added to a label to allow reformulation of the product for a specific use or all additional uses supported by a formulator or user group 

“This product may be used to formulate products for specific use(s) not listed on the 

MUP label if the formulator, user group, or grower has complied with U.S. EPA 

submission requirements regarding support of such use(s).” 

“This product may be used to formulate products for any additional use(s) not listed othe MUP label if the formulator, user group, or grower has complied with U.S. EPA submission requirements regarding support of such use(s).” 

Environmental Hazards Statements Required by the RED and Agency Label Policies 

“Environmental Hazards” “This chemical is highly toxic to aquatic organisms (fish and invertebrates) and wildlife. Do not discharge effluent containing this product into lakes, streams, ponds, estuaries, oceans or other waters unless in accordance with the requirements of a National Pollutant Discharge Elimination System (NPDES) permit and the permitting 

authority has been notified in writing prior to discharge. Do not discharge effluent containing this product to sewer systems without previously notifying the local sewagtreatment plant authority. For guidance contact your state Water Board or Regional 

Office of the EPA” 

50
Description Required Labeling 

End Use Products Intended for Occupational Use (WPS) 

Restricted Use Pesticide “RESTRICTED USE PESTICIDE” 

“Due to Acute Oral and Dermal Toxicity and Risks to Wildlife and Aquatic Organisms.” “For retail sale to, and use only by Certified Applicators or persons under the direct supervision of a Certified Applicator, and only for those uses covered by the Certified Applicator’s certification.” 

Handler PPE requirements (all formulations) 

Note the following information when preparing labeling for all end use products: For sole-active-ingredient end-use products that contain terbufos the product label must be revised to adopt the handler personal protective equipment (PPE)/engineering control requirements set forth in this section. Any conflicting PPE requirements on thcurrent label must be removed. 

For multiple-active-ingredient end-use products that contain terbufos, the handler PPE/engineering control requirements set forth in this section must be compared with the requirements on the current label, and the more protective language must be 

retained. For guidance on which requirements are considered to be more protective, sPR Notice 93-7. PPE that is established on the basis of Acute Toxicity testing with the end-use productmust be compared with the active ingredient PPE specified below in this document. 

The more protective PPE must be placed in the product labeling. For example, the 

Handler PPE in this RED does not require protective eyewear which may be required by the Acute Toxicity testing for the end-use product. For guidance on which PPE is considered more protective, see PR Notice 93-7. 

51
Description Required Labeling 

PPE Requirements “Personal Protective Equipment (PPE)” Established by the RED for the polymer based “Some materials that are chemical-resistant to this product are” (registrant inserts Granular Formulations correct chemical-resistant material). “If you want more options, follow the (20 CR) not marketed instructions for category [registrant inserts A,B,C,D,E,F,G,or H] on an EPA chemicalin a closed loading resistance category selection chart.” system (Lock ‘n Load), or any other system that “Loaders applicators and other handlers must wear: meets the specifications – coveralls over long-sleeved shirt and long pants, of the WPS. – chemical resistant gloves, 

– chemical resistant footwear plus socks.” 

Note: SLN products are not eligible for “In addition to the above, loaders and persons cleaning equipment must wear: reregistration if they are - chemical resistant apron not marketed in a - a non-powered air purifying cartridge respirator equipped with an organic vapor (OVclosed loading system. removing cartridge or canister plus an N-, R- or P- series filter.” 

Note to Registrant: If the product contains oil or bears instructions that will allow application with an oil-containing material, the “N” designation must be dropped. 

52
Description Required Labeling 

PPE Requirements Established by the RED for the polymer based Granular Formulations (20 CR) marketed in a closed loading system (Lock ‘n Load) or any other system that meets the specifications of the WPS. Note: SLN products are only eligible for reregistration if they are marketed in a closed loading system. 

“Personal Protective Equipment (PPE)” “Some materials that are chemical-resistant to this product are” (registrant inserts correct chemical-resistant material). “If you want more options, follow the 

instructions for category [registrant inserts A,B,C,D,E,F,G,or H] on an EPA chemicalresistance category selection chart.” “Loaders must wear: - long-sleeved shirt and long pants, - shoes plus socks - chemical resistant gloves - chemical resistant apron” “See engineering controls for additional requirements” “Applicators and other handlers must wear: - coveralls over long-sleeved shirt and long pants, - chemical resistant gloves, - chemical resistant footwear plus socks.” “In addition to the above, persons cleaning equipment must use a non-powered air purifying cartridge respirator equipped with an organic vapor (OV) removing cartridgor canister plus an N-, R- or P- series filter.” Note to Registrant: If the product contains oil or bears instructions that will allow application with an oil-containing material, the “N” designation must be dropped. 

53
Description Required Labeling 

PPE Requirements Established by the RED for the clay based Granular Formulations (15 G) marketed in a closed loading system (Lock ‘n Load) or any other system that meet the specifications of the WPS 

“Personal Protective Equipment (PPE)” “Some materials that are chemical-resistant to this product are” (registrant inserts correct chemical-resistant material). “If you want more options, follow the 

instructions for category [registrant inserts A,B,C,D,E,F,G,or H] on an EPA chemicalresistance category selection chart.” “Loaders and applicators must wear: - long-sleeved shirt and long pants, - shoes plus socks.” “In addition to the above, loaders must wear: - chemical resistant gloves - chemical resistant apron.” “See engineering controls for additional requirements.” “Handlers engaged in those activities for which use of an engineering control is not possible, such as cleaning up a spill or cleaning or repairing contaminated equipment, 

must wear: - coveralls over long-sleeved shirt and long pants, - chemical resistant gloves, - chemical resistant footwear plus socks, - a non-powered air purifying cartridge respirator equipped with an organic vapor (OV

removing cartridge or canister plus an N-, R- or P- series filter.” 

Note to Registrant: If the product contains oil or bears instructions that will allow application with an oil-containing material, the “N” designation must be dropped. 

54
Description Required Labeling 

User Safety Requirements 

“Follow manufacturer's instructions for cleaning/maintaining PPE. If no such 

instructions for washables exist, use detergent and hot water. Keep and wash PPE separately from other laundry.” “Discard clothing and other absorbent materials that have been drenched or heavily contaminated with this product’s concentrate. Do not reuse them.” 

Engineering controls for the polymer based Granular Formulation (20 CR) marketed in a closed loading system (Lock ‘n Load) or any other closed system that meets the specifications of the WPS 

“Engineering Controls” “This product is formulated into a Lock ‘N Load system that meets the definition of a closed loading system in the Worker Protection Standard for Agricultural Pesticides [4CFR 170.240(d)(4)]. In addition to wearing the required PPE specified above, loaders must be provided and must have immediately available for use in an emergency, such a broken package, spill, or equipment breakdown: coveralls, chemical resistant footwear plus socks, a non-powered air purifying cartridge respirator equipped with an organic vapor (OV) removing cartridge or canister plus an N-, R- or P- series filter.” “When handlers use enclosed cabs, in a manner that meets the requirements listed in th

Worker Protection Standard (WPS) for agricultural pesticides (40 CFR 170.240(d)(4-6

the handler PPE requirements may be reduced or modified as specified in the WPS.” 

Note to Registrant: If the product contains oil or bears instructions that will allow application with an oil-containing material, the “N” designation must be dropped. 

55
Description Required Labeling 

Engineering controls for the polymer based Granular Formulation (20 CR) not marketed in a closed loading system (Lock ‘n Load) or any other closed system that meets the specifications of the WPS 

“When handlers use enclosed cabs, in a manner that meets the requirements listed in th

Worker Protection Standard (WPS) for agricultural pesticides (40 CFR 170.240(d)(4-6

the handler PPE requirements may be reduced or modified as specified in the WPS.” 

56
Description Required Labeling 

Engineering Controls “Engineering Controls” for the clay based Granular Formulations “This product is formulated into a Lock ‘N Load system that meets the definition of a (15 G) marketed in a closed loading system in the Worker Protection Standard for Agricultural Pesticides [4closed loading system CFR 170.240(d)(4)]. In addition to wearing the required PPE specified above, loaders (Lock ‘n Load), that must be provided and must have immediately available for use in an emergency, such meets the specifications a broken package, spill, or equipment breakdown: coveralls, chemical resistant of the WPS footwear plus socks, a non-powered air purifying cartridge respirator equipped with an 

organic vapor (OV) removing cartridge or canister plus an N-, R- or P- series filter.” “Applicators using motorized ground equipment must use an enclosed cab that meets 

the definition in the Worker Protection Standard for Agricultural Pesticides [40 CFR 170.240(d)(5)] for dermal protection. In addition, such applicators must: 

-- wear the personal protective equipment required above for applicators; -- be provided and must have immediately available for use in an emergency when they must exit the cab in the treated area: coveralls, chemical-resistant 

gloves, chemical-resistant footwear, and a non-powered air purifying cartridge respirator equipped with an organic vapor (OV) removing cartridge or canister plus an N-, R- or P- series filter; -- take off any PPE that was worn in the treated area before reentering the cab, and -- store all such PPE in a chemical-resistant container, such as a plastic bag, to prevent contamination of the inside of the cab.” 

57
Description Required Labeling 

User Safety Recommendations 

“User Safety Recommendations” “Users should wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet. Users should remove clothing/PPE immediately if pesticide gets inside. Then wash 

thoroughly and put on clean clothing. Users should remove PPE immediately after handling this product. Wash the outside 

gloves before removing*. As soon as possible, wash thoroughly and change into clean 

clothing.” 

Environmental Hazards “Environmental Hazards” 

“This pesticide is highly toxic to fish and wildlife and has been known to cause fish kills. Runoff may be hazardous to aquatic organisms in neighboring areas. Do not 

apply directly to water or to areas where surface water is present or to intertidal areas below the mean high-water mark. Keep out of lakes, ponds, and streams. Do not 

contaminate water when disposing of equipment wastewater or rinsate. See Directionfor Use for required buffer zones or setbacks. Birds and mammals may be killed if 

granules are not properly covered with soil in all areas of the treated field and in loading areas. Cover, incorporate or clean up product that is spilled during loading or that is visible on the soil surface in turn areas. Do not apply in wet soil conditions that may prevent the equipment from covering 

pesticide granules. Do not apply in frequently flooded areas. Under certain field and weather conditions, terbufos and its degradates have a potentiafor runoff into surface water for several weeks post-application.” 

58
Description Required Labeling 

Restricted-Entry Interval 

“Do not enter or allow worker entry into treated areas during the restricted entry interval (REI) of 48 hours. The REI is 72 hours in areas where average rainfall is less than 25 inches per year.” 

Early Re-entry Personal Protective Equipment established by the RED. 

“PPE required for early entry to treated areas that is permitted under the Worker Protection Standard and that involves contact with anything that has been treated, such as plants, soil, or water, is: - coveralls worn over long-sleeve shirt and long pants, - chemical-resistant gloves made of any waterproof material, - chemical-resistant footwear plus socks, and - protective eyewear” 

Notification Statement “Notify workers of the application by warning them orally and by posting warning 

signs at entrances to treated areas.” 

General Application Restrictions 

“Do not apply this product in a way that will contact workers or other persons, either directly or through drift. Only protected handlers may be in the area during applicatio

For any requirements specific to your State or tribe, consult the agency responsible for 

pesticide regulation.” 

59
Description Required Labeling 

Other Application Restrictions 

Labels must be revised to reflect the reduced the application rate on sorghum from 1.9lbs. a.i. per acre to 1.70 lbs. a.i. per acre. Labels must be revise to reflect the following loader and applicator requirements to minimize the potential for run-off to surface water: “- maintain a 500 ft. vegetative buffer between treated area and surface water on 

neighboring land, 

- maintain a 500 ft. vegetative buffer between a standpipe drain outlet and surface wat

on neighboring land, 

- maintain a 66 ft. setback between the treated area and entry points to surface water 

bodies on non-highly erodible soils, 

- maintain a 300 ft. setback between the treated area and entry points to surface water 

bodies on highly erodible soils, 

- maintain a 66 ft. setback between treated area and standpipes on terraced fields as we

as 66 ft. vegetative buffer between the tile outlet and surface water bodies. 

- No loading, rinsing, and washing equipment within 300 ft. from surface water bodies 

or within 50 ft. from wells unless conducted on an impervious surface. 

- all setbacks must be planted to a crop or seeded with grass or other suitable cover an

all vegetative buffers must be seeded with grass or other suitable cover, 

-place granules in a 7 inch band over the row, in front of the press wheel, and incorporate into the top 1 inch of soil for banded applications on corn, -no over the top applications for European corn borer control, -to prevent channeling of surface water run-off, adjust the planter row-cleaners appropriately to prevent rows lower in height than adjacent soil.” 

Instructions in the Labeling Required section appearing in quotations represent the exact language that must appeaInstructions in the Labeling Required section not in quotes represents actions that the registrant must take to amend product registrations. 

60
VI. Related Documents and How to Access Them 

This interim Reregistration Eligibility Document is supported by documents that are 

presently maintained in the OPP docket. The OPP docket is located in Room 119, Crystal Mall #2, 

1921 Jefferson Davis Highway, Arlington, VA. It is open Monday through Friday, excluding legal 

holidays from 8:30 am to 4 pm. 

The docket initially contained preliminary risk assessments and related documents as of 

August 7, 1998. Sixty days later the first public comment period closed. The EPA then 

considered comments, revised the risk assessment, and added the formal “Response to Comments” 

document and the revised risk assessment to the docket on September 1, 1999. 

All documents, in hard copy form, may be viewed in the OPP docket room or downloaded 

or viewed via the Internet at the following site: "http://www.epa.gov/pesticides/op." 

61
 
VI. APPENDICES 

62
 
Appendix A. TABLE OF USE PATTERNS ELIGIBLE FOR REREGISTRATION 

Site Application Type Application Timing Application Equipment 

Formulation Maximum 

Single 

Application 

Rate, ai 

Maximum 

Number of 

Applications 

Per Season 

Maximum 

Seasonal 

Rate, ai 

Minimum 

Spray 

Interval 

(days) 

Preharvest 

Interval, 

(days) 

Reentry 

Interval 

(days) 

Use Directions and 

Food/Feed Crop Uses 

Corn, field, pop, sweet 

63
Site 

Application Type Application Timing Application Equipment 

Formulation Maximum 

Single 

Application 

Rate, ai 

Maximum 

Number of 

Applications 

Per Season 

Maximum 

Seasonal 

Rate, ai 

Minimum 

Spray 

Interval 

(days) 

Preharvest 

Interval, 

(days) 

Reentry 

Interval 

(days) 

Use Directions and 

Banded, In 

furrow 

At plant Ground 

15% granular 20% granular 

1.3 lb/A 1 1.3 lb/A NA1 NA 2 days Buffers to be implemented are; 1) a 5

between treated area and surface wateft. vegetative buffer between a standp

water on neighboring land, 3) a 66 ft. area and entry points to surface water soils and 300 ft. on highly erodible so

treated area and standpipes on terracevegetative buffer between the tile outrestricting loading, rinsing, and washi

from surface water bodies or within 5

conducted on an impervious surface, application for European corn borer cgranules for banded applications on crow, in front of the press wheel, and iof soil, and 8) the label text will be re

channeling of surface water run-off, a

appropriately to prevent rows lower in All setbacks must be planted to a crop 

suitable cover. Require that the Counter 15G label be applications must be made using encl

Amend the North Carolina SLN regis

require the use of a closed loading sy

Sorghum, grain 

64
Site 

Application Type Application Timing Application Equipment 

Formulation Maximum 

Single 

Application 

Rate, ai 

Maximum 

Number of 

Applications 

Per Season 

Maximum 

Seasonal 

Rate, ai 

Minimum 

Spray 

Interval 

(days) 

Preharvest 

Interval, 

(days) 

Reentry 

Interval 

(days) 

Use Directions and 

Banded, Knifed In At bedding, at plant Ground 

15% granular 20% granular 

1.7 lb/A 1 1.7 lb/A NA NA 2 days Buffers to be implemented are; 1) a 5

between treated area and surface wateft. vegetative buffer between a standp

water on neighboring land, 3) a 66 ft. area and entry points to surface water soils and 300 ft. on highly erodible so

treated area and standpipes on terracevegetative buffer between the tile outrestricting loading, rinsing, and washi

from surface water bodies or within 5

conducted on an impervious surface, required to read “To prevent channeli

adjust the planter row-cleaners appropin height than adjacent soil”. All setbor seeded with grass or other suitable 

Require that the Counter 15G label be 

applications must be made using encl

Sugar beets 

65
Site Formulation Maximum Maximum Maximum Minimum Preharvest Reentry Use Directions and 

Application Type Single Number of Seasonal Spray Interval, Interval Application Timing 

Application 

Rate, ai 

Applications 

Per Season 

Rate, ai Interval 

(days) 

(days) (days) 

Application Equipment Banded, 15% granular 1.97 lb/A 1 1.97 lb/A NA NA 2 days Buffers to be implemented are; 1) a 5Modified In 

furrow, Knifed 

20% granular between treated area and surface wate

ft. vegetative buffer between a standp

In water on neighboring land, 3) a 66 ft. At plant Ground 

area and entry points to surface water soils and 300 ft. on highly erodible sotreated area and standpipes on terracevegetative buffer between the tile outrestricting loading, rinsing, and washi

from surface water bodies or within 5

conducted on an impervious surface, required to read “To prevent channeli

adjust the planter row-cleaners appropin height than adjacent soil”. All setbor seeded with grass or other suitable 

Require that the Counter 15G label be 

applications must be made using encl

Non-Food/Non-Feed Crop Uses 

Corn, field grown for seed 

66
Site Formulation Maximum Maximum Maximum Minimum Preharvest Reentry Use Directions and 

Application Type Single Number of Seasonal Spray Interval, Interval Application Timing 

Application 

Rate, ai 

Applications 

Per Season 

Rate, ai Interval 

(days) 

(days) (days) 

Application Equipment Banded, In 15% granular 1.3 lb/A 1 1.3 lb/A NA NA 2 days Buffers to be implemented are; 1) a 5

furrow 

At plant Ground 

20% granular between treated area and surface wate

ft. vegetative buffer between a standp

water on neighboring land, 3) a 66 ft. area and entry points to surface water soils and 300 ft. on highly erodible so

treated area and standpipes on terracevegetative buffer between the tile outrestricting loading, rinsing, and washi

from surface water bodies or within 5

conducted on an impervious surface, application for European corn borer cgranules for banded applications on crow, in front of the press wheel, and iof soil, and 8) the label text will be re

channeling of surface water run-off, a

appropriately to prevent rows lower in All setbacks must be planted to a crop 

suitable cover. Require that the Counter 15G label be applications must be made using encl

Amend the North Carolina SLN regis

require the use of a closed loading sy

1 NA: Not applicable 

67
Appendix B. TABLE OF GENERIC DATA REQUIREMENTS AND STUDIES USED TO MAKE T

REREGISTRATION DECISION 

GUIDE TO APPENDIX B 

Appendix B contains listing of data requirements which support the reregistration for active ingredients wit

covered by this RED. It contains generic data requirements that apply terbufos in all products, including data requ

"typical formulation" is the test substance. 

The data table is organized in the following formats: 1. Data Requirement (Column 1). The data requirements are listed in the order in which they appear i

the reference numbers accompanying each test refer to the test protocols set in the Pesticide Assessm

are available from the National technical Information Service, 5285 Port Royal Road, Springfield, V

4650. 

2. Use Pattern (Column 2). This column indicates the use patterns for which the data 

requirements apply. The following letter designations are used for the given use patterns. 

A. Terrestrial food B. Terrestrial feed C. Terrestrial non-foodD. Aquatic foodE. Aquatic non-food outdoorF. Aquatic non-food industrial G. Aquatic non-food residentialH. Greenhouse foodI. Greenhouse non-foodJ. Forestry

68
K. Residential 

L. Indoor foodM. Indoor non-foodN. Indoor medicalO. Indoor residential

3. Bibliographic Citation (Column 3). If the Agency has acceptable data in its files, this column list th

each study. This normally is the Master Record 

Identification (MIRD) number, but may be a "GS" number if no MRID number has been assigned. Bibliography appendix for a complete citation of the study. 

69
APPENDIX B
 

Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S)
 

PRODUCT CHEMISTRY
 

New Old
 Guideline Guideline
 Number Number 830.1550 61-1 Product Identity and All 43147501, 41297901 

Composition 

830.1600 61-2A Start. Mat. & Mnfg. All 41049501 

Process 

830.1670 61-2B Formation of All 41049501 

Impurities 

830.1700 62-1 Preliminary Analysis All 41297902 830.1750 62-2 Certification of All 43147502, 41297902 

limits 

830.1800 62-3 Analytical Method All 43147503, 41297902 830.6302 63-2 Color All 41049502 830.6303 63-3 Physical State All 41049502 830.6304 63-4 Odor All 41049502 830.7050 None UV/Visable Absorption All 830.7200 63-5 Melting Point All 41049502 

70
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S)
 830.7220 63-6 Boiling Point All 41049502 
830.7860 


Partition Coefficient 
Action 
characteristics 


ECOLOGICAL EFFECTS
 

830.7300 63-7 Density All 41049502 
830.7840 63-8 Solubility All 41049502 
830.7950 63-9 Vapor Pressure All 41049502 
830.7370 63-10 Dissociation Constant All 41049502 
830.7550 63-11 Octanol/Water All 41049502 
830.7000 63-12 pH All 41049502 
830.6313 63-13 Stability All 41049502 
830.6314 63-14 Oxidizing/Reducing All 41049502, 43147503 
830.6315 63-15 Flammability All 41049502 
830.6316 63-16 Explodability All 41049502 
830.6317 63-17 Storage Stability All 41049502 
830.7100 63-18 Viscosity All 41049502 
830.6319 63-19 Miscibility All 41049502 
830.6320 63-20 Corrosion All 41049502 


71
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S) 850.2100 71-1 Avian Acute Oral 

Toxicity Test 

FEOTER02 

850.2200 71-2 Avian Dietary Toxicity 

Test 

00035120, 00087717, 

850.2300 71-4 Avian Reproduction 

Test 

00097892, 00161574, 

None 71-5A Simulated Field Study FEOTER01, 00085179, 

40985501, 40993501, 41508801, 41849201 

None 71-5B Terrestrial Field 

Study 

BAOTER01, 00085178, 00087726 

850.1075 72-1 Fish Acute Toxicity FEOTER04, FEOTER05, 

00085176, 00087718 

950.1010 72-2 Aquatic Invertebrate FEOTER03, 00085176 None 72-3A Estuarine/Marine 

Toxicity - Fish 

41373602, 41373603 

None 72-3B Estuarine/Marine 

Toxicity - Mollusk 

00162524, 42381501 

None 72-3C Estuarine/Marine 

Toxicity - Shrimp 

00162523, 41297903 

None 72-4A Fish- Early Life Stage 00162525, 40009301, 850.1500 72-5 Life Cycle Fish Reserved 

72
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S) None 72-6 Aquatic Org. 

Accumulation 

Waived, 41373603
 

850.1950 72-7A 

TOXICOLOGY 

Simulated FieldAquatic Organisms Waived
 

870.1100 81.1 Acute Oral-Rat 00029863
 870.1200 81-2 Acute Dermal-Rabbit 258710
 870.1300 81-3 Acute Inhalation-Rat 41538101
 870.2400 81-4 870.2500 81-5 

Primary Eye Irritation Primary Skin 

Irritation 

0044957
 00044957
 

870.2600 81-6 Dermal Sensitization 44942302
 870.6100 81-7 870.6200 81-8 870.3100 82-1 870.3200 82-2 870.3465 82-4 

Delayed Neurotoxicity Acute Neurotoxicity Subchronic 90 Day Oral 

Toxicity 

21-Day Dermal ­

Rabbit/Rat 

Subchronic Inhalation 

Toxicity 

00037472
 44672003
 44842302
 

00085169, 40374701, 44450601, 44520501, 00258710
 

73
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S)
 870.4100 83-1 Chronic Toxicity
 00263678, 40374701
 870.3700 83-3A	 Developmental
 00147533
 

Toxicity-Rat
 

870.3700 83-3B Developmental Toxicity
 00147533, 40886301, 

- Rabbit
 

870.3800 83-4	 2-Generation
 00085172, 43649402
 

Reproduction - Rat
 

870.4300 83-5	 Combined Chronic
 00049236, 40089602, 

Toxicity/
 Carcinogenicity
 

870.7485 85-1 General Metabolism
 42348801
 

OCCUPATIONAL/RESIDENTIAL EXPOSURE
 

875.2100 132-1A	 Foliar Residue
 

Dissipation
 

875.2400 133-3	 Dermal Passive
 

Dosimetry Exposure
 

875.2500 133-4	 Inhalation Passive
 Waived
 

Dosimetry Exposure
 

ENVIRONMENTAL FATE
 

835.2120 161-1	 Hydrolysis of Parent
 44862501
 

and Degradates
 

74
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S) 
835.2240 161-2 Photodegradation -


Water
 

00161567, 41181101
 

835.2410 161-3 Photodegradation -


Soil
 

Waived
 

835.2370 161-4 Photodegradation - Air
 Waived
 835.4100 162-1 Aerobic Soil
 

Metabolism
 

00156853
 

835.4200 162-2 Anaerobic Soil
 

Metabolism
 

41749801
 

835.4300 162-4 Aerobic Aquatic
 

Metabolism
 

44672004, 44862502
 

835.1240 163-1 Leaching/Adsorption/De
 

sorption
 

41373604
 

835-1410 163-2 Volatility-Lab
 Waived
 835-8100 163-3 Volatility-Soil
 Reserved
 835.6100 164-1 Terrestrial Field
 

Dissipation
 

41883100, 44381201
 

835-6500 164-5 Long-Term Soil
 

Dissipation
 

Reserved
 

860-1900 165-2 Field Rotational Crop
 40940701
 

75
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT None 165-4	 Bioaccumulation in
 

Fish
 

RESIDUE CHEMISTRY
 860-1200 171-3 Directions for Use
 860.1300 171-4B	 Nature of Residue -


Livestock
 

USE PATTERN CITATION(S)
 

41373603, 41373605
 41475803, 41475804, 

860.1340 860.1340 860.1380 860.1480 860.1500 860.1500 860.1500 

171-4C	 171-4D	 171-4E 171-4J 171-4K 171-4K	 171-4K	 

Residue Analytical
 Method - Plants
 Residue Analytical
 Method - Animals
 Storage Stability
 Magnitude of Residues
 - Meat/Milk/Poultry
 /Egg
 Crop Field Trials 
 (Sugar Beets)
 Crop Field Trials
 (Corn-Field)
 Crop Field Trials
 (Sorghum)
 

41475804
 Reserved
 

40940701, 41373606, 43649401, 44464601
 

Reserved 
 41569401, 442679
 41955601
 41569402, 42661801
 

76
Data Supporting Guideline Requirements for the Reregistration o

REQUIREMENT USE PATTERN CITATION(S) 860.1520 171-4L 860.1520 171-4L 

OTHER 

Processed Foods (Corn, 

Field) 

Processed Foods 

(Sorghum, Grain) 

41955601, 43237800
 41569402, 43237800
 

None 82-3SS Human Incident Data None 163-ASS Monitoring Studies- Soil 870-6200 870,6200 870-6300 

None None None 

Neurotox Screening 

Battery-Acute 

Neurotox Screening 

Battery-Acute 

Developmental Neurotox 

77
Appendix C. TECHNICAL SUPPORT DOCUMENTS 

Additional documentation in support of this RED is maintained in the OPP docket, located 

in Room 119, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA. It is open Monday 

through Friday, excluding legal holidays, from 8:30 am to 4 pm. 

The docket initially contained preliminary risk assessments and related documents as of 

August 10, 1998. Sixty days later the first public comment period closed. The EPA then 

considered comments, revised the risk assessment, and added the formal “Response to Comments” 

document and the revised risk assessment to the docket on June 16, 1999. 

All documents, in hard copy form, may be viewed in the OPP docket room or downloaded 

or viewed via the Internet at the following site: 

www.epa.gov/pesticides/op 

These documents include: 

HED Documents: 

3.	 Organophosphate Pesticides: Terbufos Availability of Revised Risk 

Assessment (FR Notice) 

4. Human Health Risk Assessment: Terbufos 

5. Terbufos Toxicology Chapter for RED 

6.	 Terbufos: Revised Acute and Chronic Dietary Exposure Analyses for the 

HED Revised Risk Assessment 

7.	 Terbufos: Revised Probabilistic (Monte Carlo) Dietary Exposure Analysis 

and Supporting Documentation 

8.	 Terbufos: Revised Probabilistic (Monte Carlo) Acute Dietary Exposure and 

Risk 

9.	 Terbufos: Comprehensive Report of the Toxicological Endpoints Selection 

Report of the Hazard Identification Assessment Review Committee 

(HIARC) 

10. Terbufos: Report of the FQPA Safety Factor Committee 

11.	 The Revised Occupational and Residential Exposure Aspects of the HED 

Chapter of the RED for Terbufos 

EFED Documents: 

78
 
12.	 Terbufos: Revised EFED RED Chapter Revision of Fate and Transport and 

Water Resources 

79
 
Appendix D.	 CITATIONS CONSIDERED TO BE PART OF THE DATA BASE 

SUPPORTING THE INTERIM REREGISTRATION DECISION 

(BIBLIOGRAPHY) 

GUIDE TO APPENDIX D 

1.	 CONTENTS OF BIBLIOGRAPHY. This bibliography contains citations of all studies 

considered relevant by EPA in arriving at the positions and conclusions stated elsewhere in 

the Reregistration Eligibility Document. Primary sources for studies in this bibliography 

have been the body of data submitted to EPA and its predecessor agencies in support of 

past regulatory decisions. Selections from other sources including the published literature, 

in those instances where they have been considered, are included. 

2.	 UNITS OF ENTRY. The unit of entry in this bibliography is called a "study". In the case 

of published materials, this corresponds closely to an article. In the case of unpublished 

materials submitted to the Agency, the Agency has sought to identify documents at a level 

parallel to the published article from within the typically larger volumes in which they 

were submitted. The resulting "studies" generally have a distinct title (or at least a single 

subject), can stand alone for purposes of review and can be described with a conventional 

bibliographic citation. The Agency has also attempted to unite basic documents and 

commentaries upon them, treating them as a single study. 

3.	 IDENTIFICATION OF ENTRIES. The entries in this bibliography are sorted numerically 

by Master Record Identifier, or "MRID” number. This number is unique to the citation, 

and should be used whenever a specific reference is required. It is not related to the sixdigit "Accession Number" which has been used to identify volumes of submitted studies 

(see paragraph 4(d)(4) below for further explanation). In a few cases, entries added to the 

bibliography late in the review may be preceded by a nine character temporary identifier. 

These entries are listed after all MRID entries. This temporary identifying number is also 

to be used whenever specific reference is needed. 

4.	 FORM OF ENTRY. In addition to the Master Record Identifier (MRID), each entry 

consists of a citation containing standard elements followed, in the case of material 

submitted to EPA, by a description of the earliest known submission. Bibliographic 

conventions used reflect the standard of the American National Standards Institute (ANSI), 

expanded to provide for certain special needs. 

a	 Author. Whenever the author could confidently be identified, the Agency has 

chosen to show a personal author. When no individual was identified, the Agency 

has shown an identifiable laboratory or testing facility as the author. When no 

author or laboratory could be identified, the Agency has shown the first submitter 

as the author. 

80
 
b.	 Document date. The date of the study is taken directly from the document. When 

the date is followed by a question mark, the bibliographer has deduced the date 

from the evidence contained in the document. When the date appears as (1999), the 

Agency was unable to determine or estimate the date of the document. 

c.	 Title. In some cases, it has been necessary for the Agency bibliographers to create 

or enhance a document title. Any such editorial insertions are contained between 

square brackets. 

d.	 Trailing parentheses. For studies submitted to the Agency in the past, the trailing 

parentheses include (in addition to any self-explanatory text) the following 

elements describing the earliest known submission: 

(1)	 Submission date. The date of the earliest known submission appears 

immediately following the word "received." 

(2)	 Administrative number. The next element immediately following the word 

"under" is the registration number, experimental use permit number, petition 

number, or other administrative number associated with the earliest known 

submission. 

(3)	 Submitter. The third element is the submitter. When authorship is defaulted 

to the submitter, this element is omitted. 

(4)	 Volume Identification (Accession Numbers). The final element in the 

trailing parentheses identifies the EPA accession number of the volume in 

which the original submission of the study appears. The six-digit accession 

number follows the symbol "CDL," which stands for "Company Data 

Library." This accession number is in turn followed by an alphabetic suffix 

which shows the relative position of the study within the volume. 

81
 
BIBLIOGRAPHY 

MRID CITATION 

____________________________________________________
 

00029863 	 Consultox Laboratories (1975) Acute Oral and Percutaneous Toxicity 

Evaluations. (Unpublished study received Feb 3, 1976 under 2749-425; 

submitted by Aceto Chemical Co., Inc., Flushing, N.Y.; CDL:241780-A) 

00035120 	 Krize, J.W.; Terrell, Y. (1978) Report: Avian Dietary LC50 (5-Day Dietary 

Exposure) of Enlist Technical (Terbufos Technical) EPA File Symbol 2749 UEL 

to Mallard Duck: Laboratory No. 8E-3451. (Unpublished study received Mar 27, 

1979 under 2749-425; prepared by Cannon Laboratories, Inc., submitted by Aceto 

Chemical Co., Inc., Flushing, N.Y.; CDL:241730-A) 

00035962 	 Fagan, E.B.; Ogg, P.J.; Van Scoik, W.S. (1972) AC 92,100 Residue Study on 

Field Corn. Planting Time and Planting Time plus Cultivation Time Treatments: 

Arcola, Illinois--1972: Report No. 72-43. (Unpublished study received Apr 9, 

1973 under 3G1340; submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:093580-H) 

00035963 	 Fagan, E.B.; Ogg, P.J.; Van Scoik, W.S. (1972) AC 92,100 Residues in Field 

Corn (Forage and Grain) Planted on 20-Inch Rows: Lexington, Illinois--1972: 

Report No. 72-44. (Unpublished study received Apr 9, 1973 under 3G1340; 

submitted by American Cyanamid Co., Princeton, N.J.; CDL:093580-J) 

00036214 	 Thompson, J.P.; Sakamoto, S.S.; Tucker, B.V.; et al. (1973) Summary: Paraquat: 

Temporary Residue Tolerance Petition--Sunflower. (Unpublished study received 

May 24, 1973 under 3G1396; submitted by Chevron Chemical Co., Richmond, 

Calif.; CDL: 095381-B) 

00036238 	 Fagan, E.B.; Owens, J.; Weis, M.E.; et al. (1972) AC 92,100 Residue Study on 

Field Corn. Planting Time and Planting Time plus cultivation Time Treatments: 

Ames, Iowa: Report No. 72-47. (Unpublished study received Apr 9, 1973 under 

3G1340; prepared in cooperation with Iowa State Univ., Dept. of Entomology and 

Zoology, submitted by American Cyanamid Co., Princeton, N.J.; CDL: 

093581-G) 

00037472 	 Smith, J.H.; Rosselet, C.; Cannelongo, B.; et al. (1972) A Neurotoxicity Study of 

AC 92,100, an Organic Phosphate Cholinesterase Inhibitor, in Hens: Project No. 

72S-788. (Unpublished study received Apr 9, 1973 under 3G1340; prepared by 

Bio/dynamics, Inc. submitted by American Cyanamid Co., Princeton, N.J.; CDL: 

093584-H) 

82
 
BIBLIOGRAPHY 

MRID CITATION 

____________________________________________________
 

00037483 	 Sleight, B.H., III (1972) The Acute Toxicity of Cycocel^(R)4 and Experimental 

Insecticide AC 92,100 to Bluegill (~Lepomis mac~μ-μ~rochirus~μ) and Rainbow 

Trout (~Salmo gairdneri~μ). (Unpublished study received Apr 9, 1973 under 

3G1340; prepared by Bionomics, Inc., submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:093584-U) 

00042017 	 American Cyanamid Company (1973) Summary--Counter-Related Residues in 

Corn. (Unpublished study received May 1, 1974 under 4F1496; CDL:091452-A) 

00042018 	 American Cyanamid Company (1973) Exhibit I: [Counter]. (Unpublished study 

received May 1, 1974 under 4F1496; CDL:091452-B) 

00042019 	 Higham, J.W.; Manuel, A.J.; Peterson, R.P.; et al. (1974) [Efficacy of Counter 

and Other Herbicides on Corn]: Report No. C-415. Includes method M-336 dated 

Jun 21, 1972. (Unpublished study including report nos. C-416 and C-425, 

received May 1, 1974 under 4F1496; prepared in cooperation with Quality 

Control Laboratories and others, submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:091452-C) 

00042020 	 Higham, J.W.; Manuel, A.J.; Congleton, W.F.; et al. (1974) Counter^(R)4 15G: 

Total Counter (CL 92,100)-Related Residues in Soybean Commodities: Immature 

Plant, Harvest Plant and Harvest Beans (Kansas and Iowa): Report No. C-429. 

Includes method M-480 dated Jan 9, 1974. (Unpublished study received May 1, 

1974 under 4F1496; prepared in cooperation with Farmland Industries and Iowa 

State Univ., Dept. of Zoology & Entomology, submitted by American Cyanamid 

Co., Princeton, N.J.; CDL: 091452-D) 

00042021 	 Manuel, A.J.; Elenewski, C.A. (1974) Counter (CL 92,100) Stability of Residues 

in Counter-Treated Corn Grain and Forage Samples When Stored in the Frozen 

State: Report No. C-430. Includes method M-336 dated Jun 21, 1972. 

(Unpublished study received May 1, 1974 under 4F1496; submitted by American 

Cyanamid Co., Princeton, N.J.; CDL:091452-F) 

00042022 	 Manuel, A.J. (1973) Counter (CL 92,100): Confirmatory Gas-Liquid 

Chromatography Test for Counter Residues in Corn Grain and Forage, and in 

Animal Tissues: Report No. C-379. Includes method M-460 dated Sep 27, 1973. 

(Unpublished study received May 1, 1974 under 4F1490; submitted by American 

Cyanamid Co., Princeton, N.J.; CDL:091452-G) 

83
 
BIBLIOGRAPHY 

MRID CITATION 

____________________________________________________
 

00044957 	 American Cyanamid Company (1972) Toxicity Data of O,O-Diethyl 

S(tert.-butylthiomethyl) phosphorodithioate: Report A-72-3. (Unpublished study 

received Aug 1, 1974 under 241-241; CDL: 100877-A) 

00049236 	 Rapp, W.R.; Wilson, N.H.; Mannion, M.; et al. (1974) A Three and Twenty-Four 

Month Oral Toxicity and Carcinogenicity Study of AC 92,100 in Rats: Project 

No. 71R-725. (Unpublished study received May 29, 1975 under 241-238; 

prepared by Biodynamics, Inc., submitted by American Cyanamid Co., Princeton, 

N.J.; CDL: 224096-A) 

00085167 	 American Cyanamid Company (1973) Toxicity Data: Sulfoxide,~tert~μ.-Butyl 

(μ~tert~μ.-Butylsolfonyl) Methyl: Report A-73-20. (Unpublished study received 

May 1, 1974 under 4F1496; CDL:090808-H) 

00085169 	 Kruger, R.; Feinman, H.; (1973) 30-day Subacute Dermal Toxicity in Rabbits of 

AC-92100: Laboratory No. 1611. (Unpublished study received May 1, 1974 

under 4F1496; prepared by Food and Drug Research Laboratories, Inc., submitted 

by American Cyanamid Co., Princeton, N.J.; CDL:090808-J) 

00085172 	 Smith, J.M.; Kasner, J.A.; Wilson, N.H.; et al. (1972) A Three Generation 

Reproduction Study of Pesticide AC 92,100 in Rats: Project No. 71R-727. 

(Unpublished study received May 1, 1974 under 4F1496; prepared by 

Bio/dynamics, Inc., submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:090808-M) 

00085176 	 Bentley, R.E. (1973) Acute Toxicity of Counter^(TM)4 to Bluegill (μ~Lepomis 

macrochirus~μ), Channel Catfish (μ~Ictalurus punc~μ-μ~tatus~μ) and Crayfish 

(μ~Procambarus clarkii~μ). (Unpublished study received May 1, 1974 under 

4F1496; prepared by Bionomics, Inc., submitted by American Cyanamid Co., 

Princeton, N.J.; CDL:090808-Q) 

00085178 	 Labisky, R.F.; Anderson, W.L. (1973) Effects of Field Applications of 

Counter^(R)4 Soil Insecticide on Wildlife. (Unpublished study received May 1, 

1974 under 4F1496; prepared by Illinois Natural History Survey, submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:090808-T) 

00085179 	 Labisky, R.F. (1974) Responses of Confined Hen Pheasants to Simulated Field 

Applications of Counter^(R)4 Soil Insecticide. (Unpublished study received May 

84
 
BIBLIOGRAPHY 

MRID CITATION 

____________________________________________________
 

1, 1974 under 4F1496; prepared by Illinois Natural History Survey, submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:090808-U) 

00085180 	 Manuel, A.J. (1973) Counter^(TM)4 15G Soil Insecticide; CL 92,100 and Its 

Metabolites in Wildlife Tissues and Eggs: Report No. C-377. (Unpublished study 

received May 1, 1974 under 4F1496; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL: 090808-V) 

00085183 	 Manuel, A.J. (1973) Counter^(TM)4 (CL 92,100) Related Residues in Pheasant 

Muscle, Liver, Skin, Kidney and Fat: Report No. C-378. (Unpublished study 

received May 1, 1974 under 4F1496; submitted by American Cyanamid Co., 

Princeton, N.J.; CDL: 090808-Y) 

00087717 	 Roberts, S.; Wineholt, R.L. (1976) 81-day Dietary LC50 Study of Terbufos in 

Bobwhite Quail and Mallard Duck: Laboratory No. 6E-3165. (Unpublished study 

received Nov 24, 1976 under 2749-427; prepared by Cannon Laboratories, Inc., 

submitted by Aceto Chemical Co., Inc., Flushing, N.Y.; CDL:226950-A) 

00087718 	 Roberts, S.; Wineholt, R.L. (1976) Static 96-hour Toxicity Study of Terbufos in 

Bluegill Sunfish and Brown Trout: Laboratory No. 6E-3166. (Unpublished study 

received Nov 24, 1976 under 2749-427; prepared by Cannon Laboratories, Inc., 

submitted by Aceto Chemical Co., Inc., Flushing, N.Y.; CDL:226951-A) 

00087726 	 Wang, G.T. (1973) Letter sent to Harold H. Nau dated Jun 21, 1973: Post-mortem 

examination--wildlife. (Unpublished study received on unknown date under 

unknown admin. no.; submitted by American Cyanamid Co., Princeton, N.J.; 

CDL:223457-A) 

00091452 See MRID Numbers 42017 to 42022 

00097892 	 Fink, R.; Reno, F.E. (1973) Final Report: One-generation Reproduction 

Study--Mallard Ducks: Project No. 362-146. (Unpublished study received May 

1, 1974 under 4F1496; prepared by Environmental Sciences Corp., submitted by 

American Cyanamid Co., Princeton, N.J.; CDL:090808-R) 

00109446 	 Daly, I.; Rinehart, W.; Martin, A. (1979) A Three Month Feeding Study of 

Counter Terbufos Insecticide in Rats: Project No. 78-2343. (Unpublished study 

85
 
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MRID CITATION 

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received Aug 5, 1982 under 241-238; prepared by Bio/dynamics, Inc., submitted 

by American Cyanamid Co., Princeton, NJ; CDL:247985-A) 

00144805 	 Fischer, J. (1985) Rabbit Dermal LD50 (Intact Skin): Report No:A85-54. 

Unpublished study prepared by American Cyanamid Co. 3 p. 

00144806 	 Rusch, G. (1980) A Two Week Inhalation Toxicity Study of Technical Counter 

Terbufos in the Rat: Project No. 78-7168. Unpublished study prepared by 

Bio/Dynamics Inc. 346 p. 

00147532 	 MacKenzie, K. (1984) A Teratology Study with AC 92, 100 in Rabbits: Study 

No. 6123-116. Unpublished study prepared by Hazleton Laboratories America, 

Inc. 62 p. 

00147533 	 Rodwell, D. (1985) A Teratology Study with AC 92, 100 in Rats: Project No. 

WIL-35014: Final Report. Unpublished study prepared by WIL Research 

Laboratories, Inc. 212 p. 

00147534 	 American Cyanamid Co. (1983) Sample Identification, Purity and Minor 

Component Profile ?Counter Terbufosσ. Unpublished study. 28 p. 

00156853 	 Peterson, R. (1983) Counter Terbufos (CL 92,100): Aerobic and Anaerobic 

Metabolism of CL 92,100 in a Silt Loam Soil: Project No. 0402: Report No. 

PD-M Volume 20-4. Unpublished study prepared by American Cyanamid Co. 

52 p. 

00158606 	 Higham, J. (1984) Counter Terbufos (CL 92,100/10-G): Residues of Total CL 

92,100-related Residues in Whole Bananas (GND; Costa Rica, 1983) (C-2260): 

Report No. C-2438. Unpublished study prepared by American Cyanamid Co. 

with summary of several residue studies appended. 13 p. 

00158607 	 Bohn, W. (1984) Counter Terbufos (CL 92,100/10-G): Residues of Total CL 

92,100-related Compounds in Whole Bananas (GND; Costa Rica, 1984) 

(C-2260): Report No. C-2494. Unpublished study prepared by American 

Cyanamid Co. 7 p. 

86
 
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00158608 	 Bohn, W.; Behm, J. (1985) Counter Terbufos (CL 92,100/10-G): Residues of 

Total CL 92,100-related Compounds in Bananas (GND; Costa Rica, 1984) 

(C-2260): Report No. C-2621. Unpublished study prepared by American 

Cyanamid Co. 10 p. 

00158609 	 Bohn, W. (1984) Counter Terbufos (CL 92,100/10-G): Residues of Total CL 

92,100-related Compounds in Whole Bananas (GND; Costa Rica, 1984) 

(C-2260): Report No. C-2493. Unpublished study prepared by American 

Cyanamid Co. 7 p. 

00158610 	 Bohn, W.; Behm, J. (1986) Counter Terbufos (CL 92,100/10-G): Residues of 

Total CL 92,100-related Compounds in Bananas (GND; Costa Rica, 1984) 

(C-2260): Report No. C-2674. Unpublished study prepared by American 

Cyanamid Co. 16 p. 

00158611 	 Khunachak, A.; Behm, J. (1986) Counter Terbufos (CL 92,100/10-G): Residues 

of Total CL 92,100-related Compounds in Whole Banana (GND; Costa Rica, 

1985) (C-2260): Report No. C-2705. Unpublished study prepared by American 

Cyanamid Co. 15 p. 

00158612 	 Khunachak, A.; Behm, J. (1986) Counter Terbufos (CL 92,100/10-G): Residues 

of Total CL 92,100-related Compounds in Whole Banana, Peel and Pulp (GND; 

Costa Rica, 1985) (C-2260): Report No. C-2704. Unpublished study prepared by 

American Cyanamid Co. 14 p. 

00158613 	 Khunachak, A.; Behm, J. (1986) Counter Terbufos (CL 92,100/10-G): Residues 

of Total CL 92,100-related Compounds in Whole Banana, Peel and Pulp (GND; 

Honduras, 1985) (C-2260): Report No. C-2706. Unpublished study prepared by 

American Cyanamid Co. 13 p. 

00158614 	 Elenewski, C. (1983) Counter Terbufos (CL 92,100): Validation of GC Method 

M-1340 for the Determination of Total CL 92,100-related Residues in Whole 

Bananas: Report No. C-2260. Unpublished study prepared by American 

Cyanamid Co. 13 p. 

00160387 	 Beavers, J. (1984) A Dietary LC50 Study in the Bobwhite with AC 92,100: Final 

Report: Project No. 130-134. Unpublished study prepared by Wildlife 

International Ltd. 18 p. 

87
 
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00161566 	 McAllister, W. (1986) Letter sent to N. Luke dated May 30, 1986: The early life

stage toxicity of Ýcarbon 14 ̈-Counter (carbon 14-Cl 92,100) to rainbow trout in a 

flow-through system: ABC study No. 34267. Prepared by Analytical BioChemistry Laboratories, Inc. 2 p. 

00161567 	 Mangels, G. (1986) Counter Insecticide, Terbufos (CL 92,100): Water Photolysis: 

Report No. PD-M 23-19: Project No. 0112. Unpublished study prepared by 

American Cyanamid Co. 29 p. 

00161572 	 Shellenberger, T. (1986) One-year Oral Toxicity Study in Purebred Beagle Dogs 

with AC 92,100: Final Report: Report No. 8414. Unpublished American 

Cyanamid Co. Report No. 981-84-118 prepared by Tegeris Laboratories, Inc. 836 

p. 

00161574 	 Beavers, J. (1986) Counter Technical: A One-generation Reproduction Study 

with the Mallard (Anas platyrhynchos): Final Report: Project No. 130-138. 

Unpublished study prepared by Wildlife International Ltd. 129 p. 

00162523 	 Forbis, A.; Schoen, L.; Leak, T.; et al. (1986) Acute Toxicity of ?Carbon 14σ-CL 

92,100 to Mysid Shrimp (Mysidopsis bahia): Final Static Acute Toxicity Report 

#32890. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, 

Inc. 246 p. 

00162524 	 Swigert, J.; McAllister, W.; Bowman, J.; et al. (1986) Acute Toxicity of ?Carbon 

14σ-CL 92, 100 to Sheepshead Minnows (Cyprinodon variegatus): Final Static 

Acute Toxicity Rept. #32889. Unpublished study prepared by Analytical 

Bio-Chemistry Laboratories, Inc. 279 p. 

00162525 	 Forbis, A.; Land, C.; Bunch, B. (1986) Chronic Toxicity of CL 92, 100 to 

Daphnia magna Under Flow-Through Test Conditions: ABC Final Rept. #32891. 

Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 164 

p. 

00258710 See MRID Numbers 00144805 to 00144806 

00258787 See MRID Numbers 00147532 to 00147534 

88
 
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MRID CITATION 

____________________________________________________
 

00262634 See MRID Numbers 00158606 to 00158614 

00263678 See MRID Numbers 00161566 and 00161572 

40009301 	 McAllister, W. (1986) Early Life Stage Toxicity of ?Carbon 14σ-CL 92100 to 

Rainbow Trout (Salmo gairdneri) in a Flow-through System: Fish Early Life 

Stage Study: Study No. 34267: Final Report. Unpublished study prepared by 

Analytical Bio-Chemistry Laboratories, Inc. 382 p. 

40089603 	 Shellenberger, T. (1986) Chronic Dietary Toxicity and Oncogenicity Study with 

AC 92,100 in Mice: Chronic Toxicity and Oncogenicity--Mouse: Laboratory 

Project ID. 8422. Unpublished study prepared by Tegeris Laboratories, Inc. 

1566 p. 

40098602 	 Koons, J.; Sullivan, W. (1987) Determination of Fenarimol and Metabolites in 

Grapes: Laboratory Project AM-AA-CA-R096-AB-755. Unpublished study 

prepared by Lilly Research Laboratories. 10 p. 

40365901 	 Bohn, W. (1984) Counter Terbufos (CL 92,100/10G): Residues of Total CL 

92,100-related Compounds in Coffee Beans (Costa Rica): Report Nos. C-2459 

and C-2351. Unpublished study prepared by American Cyanamid Co. 24 p. 

40374701 	 Shellenberger, T. (1984) 28-Day Oral Toxicity in the Dog with AC 92,100: 

Report No. 87019. Unpublished study prepared by Tegeris Laboratories Inc. 89 

p. 

40886301 	 Hoberman, A. (1988) A Developmental Toxicity (Embryo-fetal Toxicity 

Teratogenicity) Study with AC 92,100 in Rabbits: Project ID: Argus Research 

Laboratories Protocol: 101-008. Unpublished study prepared by Argus Research 

Laboratories, Inc. 243 p. 

40940701 	 Potts, C. (1988) CL 92,100 (Terbufos): Freezer Stability of Total CL 

92,100--Related Residues in Corn Grain, Plants and Straw (Progress Report) 

(C-0607): Storage Stability of Residues: Report No. C-3107: Project No. 0107. 

Unpublished study prepared by American Cyanamid Co. 10 p. 

89
 
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40966401 	 Hoberman, A. (1988) Addendum to Developmental Toxicity (Embryofetal 

Toxicity/Teratogenicity): Study with AC 92,100 in Rabbits: (Sample 

Identification and Analysis of Dosing Solutions.): Report No. 101-003. 

Unpublished study prepared by Argus Research Laboratories, Inc. 14 p. 

40985501 	 Block, E.; Brewer, L.; Carlock-Anderson, L.; et al. (1989) Laboratory, Simulated, 

and Actual Field Testing to Assess the Impacts of Counter on Non-target 

Organisms: Project No. 107. Unpublished compilation prepared by The Institute 

of Wildlife Toxicology. 985 p. 

40993501 	 Brewer, L.; Cobb, G.; Hooper, M.; et al. (1989) Thrid Year Investigation of the 

Response of Selected Wildlife Populations to Planting Time Application of 

Counter 15-G Systemic Insecticide-Nematicide in an Iowa Corn Agroecosystem: 

American Cyanamid Co. Protocol Nos. 985-87-101.1. Unpublished study 

prepared by The Institute of Wildlife Toxicology. 283 p. 

41049501 	 American Cyanamid Co. (1989) Description of Beginning Materials and 

Manufacturing Process and Discussion of Formation of Impurities for Conter 

Technical. Unpublished compilation. 83 p. 

41049502 	 American Cyanamid Co. (1989) Physical and Chemical Characteristics for 

Counter Technical. Unpublished study. 128 p. 

41181101 	 Mangels, G. (1989) Terbufos (AC 92, 100): Photodegradation in Water: 

Laboratory Project ID: E-89-14: Report No. PD-M Volume 26-37. Unpublished 

study prepared by American Cyanamid Co. 57 p. 

41297902 	 Wilson, L.; Galley, M. (1989) Certification of Limits and Analytical Method To 

Verify Certified Limits: Counter: Method Number M-1913. Unpublished study 

prepared by American Cyanamid Co. 53 p. 

41297903 	 Forbis, A. (1989) Acute Flow-through Toxicity of Carbon-14-AC 92,100 to 

Mysid Shrimp (Mysidopsis bahia): Final Report: Lab Project Number 37912; 

971-89-135. Unpublished study prepared by Analytical Bio-chemistry 

Laboratories, Inc. 235 p. 

41373602 	 Bowman, J. (1989) Acute Flow-through Toxicity of [Carbon 14]-AC 92, 100 to 

Sheepshead Minnow (Cyprinodon variegatus): ABC Laboratory Project ID: 

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37911. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, 

Inc. 240 p. 

41373603 	 Wu, J. (1989) Terbufos (CL 92,100): Metabolic Fate of [Carbon 14]-CL 92,100 in 

Bluegill Sunfish (Lepomis macrochirus): XBL Report No. RPT00018. 

Unpublished study prepared by XenoBiotic Laboratories, Inc. 43 p. 

41373604 	 Mangels, G. (1989) Adsorption/Desorption of Terbufos (CL 92,100), Terbufos 

Sulfoxide (CL 94,301), and Terbufos Sulfone (CL 94,320) on Soil Stability 

during Adsorption to Soil of Terbufos (CL 92, 100): Lab Project ID: E-88-10: 

E-89-21: E-88-23. Unpublished study prepared by American Cyanamid Co. 119 

p. 

41373605 	 Burgess, D. (1989) Uptake, Depuration and Bioconcentration of [Carbon 14]-AC 

92,100 by Bluegill Sunfish (Lepomis macrochirus): ABC Laboratory Project ID: 

37914. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, 

Inc. 487 p. 

41373606 	 Dixon, C. (1987) CL 92,100(terbufos): Freezer Stability of Total CL 

92,100-related Residues in Sugar Beet Tops and Roots: Lab Report No. C3298. 

Unpublished study prepared by American Cyanamid Co. 17 p. 

41475801 	 Tank, S.; Brewer, L.; Cobb, G.: et al. (1990) Third Year Investigation of the 

Response of Selected Wildlife Populations to Planting Time Application of 

Counter 15G Systemic Insecticide-nematicide in an Iowa Corn Agroecosystem: 

Project Number 107. Unpublished study prepared by The Institute of Wildlife & 

Environmental Toxicology. 753 p. 

41475802 	 Rhodes, J.; McAllister, W. (1990) Early Life Stage Toxicity of [Carbon 14]-AC 

92,100 to the Rainbow Trout (Oncorhynchus mykiss) under Flow-through 

Conditions: Final Report # 37913. Unpublished study prepred by Analytical 

Bio-Chemistry Laboratories, Inc. 648 p. 

41475803 	 Zulalian, J. (1990) Terbufos (CL92,100): Metabolic Fate of Carbon-14 CL92,100 

Derived Residues in Tissues and Milk of Lactating Goats: Lab Project I.D. 

M89A100PT2: Report No. PD-M Volume 27-3. Unpublished study prepared by 

American Cyanamid Co. 144 p. 

91
 
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41475804 	 Brindle, P. (1990) Terbufos (CL92,100): Metabolic Fate of Carbon-14 CL92,100 

in Tissues, Blood and Eggs of the Laying Hen: Lab Project I.D. M89A100PT1: 

Report No.PD-M Volume 27-13. Unpublished study prepared by American 

Cyanamid Co. 127 p. 

41508801 	 Pedersen, C. (1990) Counter Systemic Insecticide-nematicide: A Simulated (Pen) 

Field Study to Assess the Availability, Persistence and Toxicity of Counter 

Formulations to Brown-Headed Cowbirds (Molothrus ater) and Bobwhite Quail 

(Colinus virginianus): Lab. Project Number: BLAL #89 SP 17: CYANAMID 

971-89-123. Unpublished study prepared by Bio-Life Associates, Ltd. 166 p. 

41538101 	 Hoffman, G. (1987) An Acute Inhalation Toxicity Study with AC 92,100 in Rats: 

Bio/dynamics, Inc. Project No. 86-7970. Unpublished study prepared by 

Bio/dynamics, Inc. 244 p. 

41569401 	 Kleiner, A. (1990) CL92,100 (Terbufos/15-G): Residues of Total CL 

92,100-Related Compounds in Sugarbeet Roots and Foliage: Lab Project 

Number: C3366: C3367: C3368. Unpublished study prepared by American 

Cyanamid Co. 135 p. 

41569402 	 Kleiner, A. (1990) CL 92,100(Terbufos/15G): Residues of Total CL 

92,100-Related Compounds in Grain Sorghum: Lab Project Number: C3374: 

C3375: C3376. Unpublished study prepared by American Cyanamid Co. 103 p. 

41749801 	 Madsen, S.; Williams, M. (1990) "Anaerobic Soil Metabolism of 14c-Terbufos": 

Lab Project Number: 38612. Unpublished study prepared by Analytical 

Bio-Chemistry Laboratories, Inc. 53 p. 

41849201 	 Kendall, R. (1991) Chemical and Biochemical Analysis of Samples from the 

Study "COUNTER Systemic Insecticide-Nematicide: A Simulated (Pen) Field 

Study to Assess the Availabilty, Persistence, and Toxicity of COUNTER 

Formulations to Brown-headed Cowbirds (Molothrus ater) and Bobwhite Quail 

(Colinus virginanus)": Supplement to MRID 41508801: Lab Project Number: 

BLAL #SP 17: 971-89-123. Unpublished study prepared by Clemson Univ., 

Institute of Wildlife and Environmental Toxicology. 93 p. 

41883100 	 American Cyanamid Co. (1991) Submission of Data to Support the Registration 

Standard of Terbufos: Environmental Fate Data. Transmittal of 2 Studies. 

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41883101 	 Banks, V.; Higham, J. (1988) CL 92,100 (Terbufos/15G): Soil Rate of 

Disappearance of Terbufos (CL 92,100) and Related Compounds (CL 94,301 and 

CL 94,320) in California: Lab Project Number: C3532. Unpublished study 

prepared by American Cyanamid Co. 160 p. 

41883102 	 Higham, J. (1991) Terbufos (CL 92,100): Validation of GLC Method M-1912 for 

the Determination of Terbufos (CL 92,100) and Related Compounds (CL 94,301 

and CL 94,320) in Soil: Lab Project Number: C3544. Unpublished study 

prepared by American Cyanamid Co. 76 p. 

41955601 	 Leonard, R. (1991) CL92,100(Terbufos/15G): Residues of Total CL92, 

100-Related Residues in Field Corn after Application at the Mininum Labelled 

Use Rate and 5X the Maximum Labelled Use Rate (At Cultivation; 1990): Lab 

Project Number: C3566: C3567: C3568. Unpublished study prepared by 

American Cyanamid Co. 248 p. 

42267901 	 Glaza, S. (1992) Acute Dermal Toxicity Study of Vinyzene RP-1000 Granulated 

in Rabbits: Lab Project Number: HWI 11205765. Unpublished study prepared by 

Hazleton Wisconsin, Inc. 28 p. 

42348801 	 Cheng, T. (1992) Metabolism of [carbon 14]-Terbufos (CL 92,100) in Rats: 

Preliminary and Definitive Phases: Final Report: Laboratory Project Number: 

HWI 6123-164. Unpublished study prepared by Hazleton Wisconsin, Inc. 203 p. 

42381501 	 Sved, D.; Wisk, J. (1992) Effect of AC 92,100 on New Shell Growth in the 

Eastern Oyster (Crassostrea Virginica) Under Flow Through Test Conditions: 

Final Report: Addendum to the 45 Month Response to the Registration Standard 

Second Round Review for all Products Contained in Terbufos: Lab Project 

Number: 130A-104A: 941-91-151. Unpublished study prepared by Wildlife 

International Ltd. 93 p. 

42576900 	 American Cyanamid Co. (1992) Submission of residue data in support of the 

Terbufos registration standard. Transmittal of 1 study. 

42576901 	 Cheng, T. (1992) Terbufos (CL92,100): Metabolic Fate of (carbon 14)-Labeled 

CL 92,100 in Milk and Edible Tissues of the Lactating Goat: Lab Project 

Number: HWI 6123-174: M92A100WI1. Unpublished study prepared by 

Hazleton Wisconsin, Inc. 117 p. 

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42661801 	 Kleiner, A. (1992) CL 92,100 (terbufos/15G): Residues of Total CL 

92,100-Related Compounds in Dual Purpose Sorghum (KI; TX, 1991): Lab 

Project Number: C-3851. Unpublished study prepared by American Cyanamid 

Co. 52 p. 

43147501 	 Cortes, D.; Thomson, M. (1994) Product Identity and Discussion of Formation of 

Impurities for COUNTER Technical: Addendum: Lab Project Number: 

CHDV/VOL/29/REPORT/2. Unpublished study prepared by American 

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43147502 	 Thomson, M.; Wilson, L. (1994) Preliminary Analysis, Certification of Limits, 

and Analytical Methods for Enforcement for COUNTER Technical: (Addendum): 

Lab Project Number: APBR/308: APBR/307. Unpublished study prepared by 

American Cyanamid Co. 95 p. 

43147503 	 Rahaman, R. (1994) Physical and Chemical Characteristics for COUNTER 

Technical: Addendum: Lab Project Number: CHDV/VOL/29/REPORT/3. 

Unpublished study prepared by American Cyanamid Co. 4 p. 

43237800 	 American Cyanamid Co. (1994) Submission of residue data in support of 

registration standard for terbufos. Transmittal of 2 studies. 

43237801 	 Cheng, T.; Zulalian, J. (1994) Terbufos (CL 92,100): Metabolic Fate of 

Carbon-14 CL 92,100 Derived Residues in Tissues and Milk of Lactating Goats: 

Addendum: Lab Project Number: HWI/6123/174: 6123/174. Unpublished study 

prepared by Hazelton Wisconsin, Inc. 64 p. 

43237802 	 Higham, J.; Fisher, R. (1988) CL 92100 (terbufos/15G): Residues of Total CL 

92,100-Related Compounds in Sweet Corn Following Banded and Post 

Applications in New York, Wisconsin, and Florida: Lab Project Number: C/3093: 

C/3096: C/3109. Unpublished study prepared by American Cyanamid Co. 28 p. 

43649401 	 Wrubel, J. (1995) Summary of Previously Submitted Terbufos Data in Partial 

Fulfillment of the Requirements for Residue Commodity Storage Stability Data. 

Unpublished study prepared by American Cyanamid Co. 11 p. 

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43649402 	 Schroeder, R. (1989) A Two-Generation (Two-Litters) Reproduction Study With 

AC 92,100 to Rats: Lab Project Numbers: 86-3128: 971-87-132. Unpublished 

study prepared by Bio/dynamics, Inc. 1806 p. 

44267901 	 York, C. (1996) Terbufos (CL 92,100): Total CL 92,100-Related Residues in 

Sugar Beets After Treatment with Counter 15G Systemic Insecticide Nematicide 

Applied Postemergence: Lab Project Number: RES 95-039: RES 95-040: RES 

95-045. Unpublished study prepared by American Cyanamid Co. 422 p. 

{OPPTS 860.1500}. 

44267902 	 Higham, J.; Picard, G. (1996) Terbufos (CL 92,100): Validation of Method 

M-2457 for the Determination of Total CL 92,100-Related Residues in Sugar 

Beet Tops and Roots: Lab Project Number: RES 95-118: ABC 42332: 

CT94PT01. Unpublished study prepared by American Cyanamid Co. and ABC 

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44381201 	 Khunachak, A. (1997) CL 92,100 (Counter Systemic Insecticide Nematicide): 

Freezer Storage Stability of Residues of Terbufos (CL 92,100) and its Related 

Compounds (CL 94,301 and CL 94,320) in Soil: (Final Report): Lab Project 

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American Cyanamid Co. and ABC Labs, Inc. 60 p. {OPPTS 840.1100} 

44450600 	 American Cyanamid Co. (1997) Submission of Toxicology Data in Support of the 

Reregistration for Terbufos. Transmittal of 1 Study. 

44450601 	 Compton, D. (1997) A Preliminary Range-Finding Rat Dermal Toxicity Study 

with AC 92100 CR: Lab Project Number: 97-2518: 971-97-125. Unpublished 

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44464601 	 Higham, J. (1997) CL 92100: Freezer Storage Stability of Residues of 

Terbufos-Related Compounds (CL 94301, CL 94320, and CL 94221) in Sugar 

Beet Tops and Roots: Lab Project Number: RES 97-017: CT94PT02: 0107. 

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44520501 	 Kelly, C. (1998) A Four-Week Rat Dermal Toxicity Study with AC 92100 15G: 

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44629302 	 Khunachak, A.; Kleiner, A.; Gross, J. (1998) Crop Residue Studies: Total 

Terbufos-Related Residues in Bananas After Treatment with Counter Systemic 

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44629303 	 York, C.; Fletcher, P. (1998) Crop Residue Studies: Total Terbufos-Related 

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44672003 	 Mandella, R. (1998) An Acute Neurotoxicity Study with AC 92100 in the Rat Via 

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44672004 	 Kloppel, H. (1993) Degradation of (Carbon 14)-Terbufos in Water/Sediment 

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Fraunhofer-Institut fuer Umweltchemie und Okotoxikologie. 57 p. 

44690501 	 Compton, D. (1998) A Four-Week Rat Dermal Toxicity Study with AC 92100 

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44793301 	 Higham, J.; Walls, C.; Sweeney, R. et al. (1999) Occupational Exposure and Risk 

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44834301 	 Barraj, L.; Kidwell, J. (1999) Sensitivity Analysis Considering the Acute Dietary 

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44842302 	 Mandella, R. (1999) 13-Week Dietary Neurotoxicity Study with AC 92100 in the 

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44862501 	 Martin, C.; Heim, D. (1999) (Carbon-14)-Terbufos (AC92100) and its 

Sulfoxide(AC94301) and Sulfone(AC94320) Metabolites: Hydrolysis in Sterile 

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44862502 	 Martin, C.; Xia, C. (1999) (Carbon-14)-Terbufos (AC92100) and its 

Sulfoxide(AC94301) and Sulfone(AC94320) Metabolites: Degradation in Natural 

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Pesticides, People and Nature 1:15-24. 

DeLuca, T., Larson, J., Torma, L. and G. Algard. 1989. A Survey of 

Groundwater Contamination by Pesticides in Montana, Montana Department of 

Agriculture, Technical Report 89-1, August 1989. 

Detroy, M. 1985. Iowa Ground-Water-Quality Monitoring Program, U.S. 

Geological Survey, Open File Report 84-815, December 1985. 

Detroy, M., Hunt, P., and M. Holub. 1988. Ground-Water-Quality Monitoring in 

Iowa: Nitrate and Pesticides in Shallow Aquifers, U.S. Geological Survey, Water 

Resources Investigations Report 88-4123. 

Exner, M. and Roy Spalding. 1990. Occurrence of Pesticides and Nitrate in 

Nebraska's Ground Water, University of Nebraska, Institute of Agriculture and 

Natural Resources. 

Felsot, A., L. Wei, and J. Wilson. 1982. Environmental chemodynamic studies 

with terbufos (CounterTM) insecticide in soil under laboratory and field conditions. 

Journal of environmental science and health. Vol. B17(6), pp. 649-673. 

Felsot, A., W.N. Bruce, and K.S. Steffey. 1987. Degradation of terbufos 

(CounterTM) soil insecticide in corn fields under conservation tillage practices. 

Bulletin of Environmental Contamination and Toxicology Vol. 38:369-376. 

98
 
BIBLIOGRAPHY 

CITATION 

____________________________________________________
 

Hirsch, R.M. Alley, W.M., and Wilbur, W.B. 1988. Concepts of National Water 

Quality Assessment Program. USGS Circular 1021. 

Indiana Department of Environmental Management. 1988. Assessment of 

Nonpoint Source Pollution of Ground Water in Indiana, July 1988. 

Kelley, R.. 1985. Synthetic Organic Compound Sampling Survey of Public 

Water Supplies, Iowa Department of Natural Resources, Des Moines, IA, April 

1985. 

Kelley, R. and Wnuk, M. 1986. Little Sioux River Synthetic Organic Compound 

Municipal Well Sampling Survey, Iowa Department of Natural Resources, Des 

Moines, IA, March 1986. 

Kelley, R. 1986. 1986 Little Sioux River Pesticide Monitoring Report, Iowa 

Department of Natural Resources, Des Moines, IA, March 1988. 

Kelley, R. 1986. University of Iowa, Hygienic Laboratory, personal 

communication. 

Klaseus, T., Buzicky, G. and E. Schneider. 1988. Pesticides and Ground Water: 

Surveys of Selected Minnesota Wells, Minnesota Department of Health and 

Minnesota Department of Agriculture, February 1988. 

Klaseus, T. and Hines, J. 1989. Pesticides and Ground Water: Surveys of 

Selected Minnesota Wells, Minnesota Department of Health, August 1989. 

Kleinbaum, D.G., L.L. Kupper, and H. Morgenstern. 1982. Epidemiological 

Research. Van Nostrand Reinhold. 

Knapton, R.W., and P. Mineau. 1995. Effects of granular formulations of 

terbufos and fonofos applied to cornfields on mortality and reproductive success 

in songbirds. Ecotoxicology 4:138-153. 

Lane, L. 1987. Mississippi Pesticide Hazard Assessment Project: Annual 

Progress Report No. 15, Mississippi State University, May 1987. 

99
 
BIBLIOGRAPHY 

CITATION 

____________________________________________________
 

Mayer, F.L. and Ellersieck, M.R. 1986. Manual of acute toxicity: interpretation 

and data base for 4510 chemicals and 66 species of freshwater animals. USFWS 

Resource publ. 160. 

Mesko, T. and Carlson, G. 1988. Occurrence of Pesticides, Nitrates, Organic 

Compounds, and Trace Elements in Ground Water and Streams, Southeastern 

Missouri, 1986-87, U.S. Geological Survey Open-File Report 88-495. 

Rhode Island Department of Environmental Management. 1990. Rhode Island 

Private Well Survey Final Report. 

Sievers, D. and Fulhage, C. 1991. Quality of Rural Well Water North Missouri 

and Quality of Missouri's Agricultural Groundwater Region II Sampling, 

University of Missouri, June 1991. 

South Dakota Department of Environment and Natural Resources. 1993. 1992 

Pesticide and Nitrogen Sampling Program and Five Year SumM., February 1993. 

USEPA. 1992. Pesticides in Ground Water Database - A Compilation of 

Monitoring Studies: 1971 - 1991. Office of Prevention, Pesticides, and Toxic 

Substances. EPA 734-12-92-001. September 1992. 

USEPA Office of Water. February 1996, Drinking Water Regulations and Health 

Advisories, EPA 822-R-96-001 

United States Environmental Protection Agency, Guidelines for Exposure 

Assessment; Federal Register Volume 57, Number 104 (Friday May 29, 1992). 

USEPA, Draft Standard Operating Procedures (SOPs) For Residential Exposure 

Assessment (December 11, 1997). 

USEPA, Series 875 - Occupational and Residential Exposure Test Guidelines, 

Group B - Postapplication Exposure Monitoring Test Guidelines; Version 5.4; 

(February 10, 1998). 

USEPA, Pesticide Handlers Exposure Database, Version 1.1; (1993). 

100
 
BIBLIOGRAPHY 

CITATION 

____________________________________________________
 

USEPA, Exposure Factors Handbook, EPA Report 600/P-95/002Fa, August, 

1997. 

Terbufos: Revised Risk Assessment; (3/4/99) Chemical ID No. 105001, Case 

0109, DP Barcode D253850, From William Hazel (OPP/HED/RRB-1) to Pamela 

Noyes and Robert McNally (OPP/SRRD). 

Various Correspondence From American Cyanamid to the EPA (letters dated 

June 23, 1999; August 20, 1998; October 12, 1998; and January 15, 1999). 

Authored by Mark Galley, Director U.S. Plant Regulatory Affairs or John 

Wrubel, Product Registrations Manager, U.S. Plant Regulatory Affairs. 

Occupational And Residential Exposure Assessment And Recommendations For 

The Reregistration Eligibility Document For Terbufos; (May 18, 1995) Chemical 

ID No. 105001, Case 0109, DP Barcode D192404, From Alan P. Nielsen 

(OPP/HED/OREB) to Karen Whitby (OPP/HED/RCAB). 

Current ORE Issues Related To Terbufos (Chem # 105001) RED Status; (March 

4, 1998), DP Barcode D241134 and D243778 From Jeff Dawson 

(OPP/HED/RRB-1) to William Hazel (OPP/HED/RRB-1). 

Use and Usage Information; (7/15/99) sent by email by John Wrubel (Product 

Review Manager, American Cyanamid) to Jeff Dawson U.S. EPA 

(OPP/HED/RRB-1) with cc. to EPA CRM and U.S.D.A. 

Quantitative Usage Analysis; (July, 1999) completed by Dhol Herzi 

(EPA/OPP/BEAD). 

Final Usage Analysis For Terbufos RED; (2/8/99) From Donald Atwood and 

Kathy Davis (OPP/BEAD) to Pamela Noyes (OPP/SRRD). 

Occupational Exposure and Risk Assessment For Loaders and Applicators 

Handling Terbufos Products and Supporting Worker Exposure Studies; (3/26/99) 

Authored by Joseph Higham, Richard Honeycutt, D. Larry Merricks, Rose A. 

Sweeney, Cassi L. Walls, and Susan H Youngren; Completed by ABC 

Laboratories of Columbia MO, HERAC of Greensboro NC, Agrisearch of 

Frederick MD, Novigen Sciences of Washington DC, and American Cyanamid of 

Princeton NJ.; Project ID #s include: Exhibit 1 of EPA MRID 447933-01, 

101
 
BIBLIOGRAPHY 

CITATION 

____________________________________________________
 

Terbufos 99-02, EXA 99-004, EXA 99-006, and RES 99-003, Sponsored by 

American Cyanamid. 

Exposure of Farmworkers To Terbufos (CL 92100) While Loading COUNTER 

15G Systemic Insecticide-Nematicide With A Lock-N-Load Closed Handling 

System And Applying COUNTER 15G To Corn At Planting Time; (3/26/99) 

Authored by Joseph Higham; Completed by ABC Laboratories of Columbia MO, 

Agrisearch of Frederick MD, and American Cyanamid of Princeton NJ.; Project 

ID #s include: Exhibit 2 of EPA MRID 447933-01, Terbufos 99-02, EXA 99-004, 

EXA 99-006, and RES 99-003, Sponsored by American Cyanamid. 

Exposure of Farmworkers To Terbufos (CL 92100) While Loading COUNTER 

CR Systemic Insecticide-Nematicide From A Bag And Applying COUNTER CR 

To Corn At Planting Time; (3/26/99) Authored by Joseph Higham; Completed by 

ABC Laboratories of Columbia MO, HERAC of Greensboro NC, and American 

Cyanamid of Princeton NJ.; Project ID #s include: Exhibit 3 of EPA MRID 

447933-01, Terbufos 99-02, EXA 99-004, EXA 99-006, and RES 99-003, 

Sponsored by American Cyanamid. 

CL92100 (terbufos): Validation of GC/FPD Determinative Methods M3153, 

M3154, M3155, and M 3156 For The Determination of CL 92100 Residues In, 

Respectively, Whole Body Dosimeters, Aerosol OT Handwash and Glove Wash 

Solutions, Air Sampling Tubes and Face/Neck Wipes; (3/26/99) Authored by 

Joseph Higham, Jill Cooper, and Rose Sweeney; Completed by ABC Laboratories 

of Columbia MO, and American Cyanamid of Princeton NJ.; Project ID #s 

include: Exhibit 4 of EPA MRID 447933-01, ABC Report 44703, and RES 99­

003, Sponsored by American Cyanamid. 

Terbufos Updated Risk Assessment USDA Comments; (June 25, 1999) 

Forwarded by Therese Murtaugh of USDA. 

Terbufos (AC 92100) - Response To Registrant’s Rebuttal Regarding Reference 

Dose; Dust Generation/Characterization Studies; (July 5, 1996) Authored by Alan 

C. Levy (OPP/HED/Tox-II) to William Hazel and Christina Swartz 

(OPP/HED/RCAB). Provides cursory review of study entitled Counter CR and 

Counter 15G, Dust Generation and Characterization by V Arendt (completed on 

2/16/96, ID F-1356, submitted on 5/23/96). 

102
 
BIBLIOGRAPHY 

CITATION 

____________________________________________________
 

Exposure of Farmworkers To Terbufos (CL 92100) While Loading COUNTER 

15G Systemic Insecticide-Nematicide With A Lock-N-Load Closed Handling 

System And Applying COUNTER 15G To Corn At Planting Time; (3/26/99) 

Authored by Joseph Higham; Completed by ABC Laboratories of Columbia MO, 

Agrisearch of Frederick MD, and American Cyanamid of Princeton NJ.; Project 

ID #s include: Exhibit 2 of EPA MRID 447933-01, Terbufos 99-02, EXA 99-004, 

EXA 99-006, and RES 99-003, Sponsored by American Cyanamid. 

Exposure of Farmworkers To Terbufos (CL 92100) While Loading COUNTER 

CR Systemic Insecticide-Nematicide From A Bag And Applying COUNTER CR 

To Corn At Planting Time; (3/26/99) Authored by Joseph Higham; Completed by 

ABC Laboratories of Columbia MO, HERAC of Greensboro NC, and American 

Cyanamid of Princeton NJ.; Project ID #s include: Exhibit 3 of EPA MRID 

447933-01, Terbufos 99-02, EXA 99-004, EXA 99-006, and RES 99-003, 

Sponsored by American Cyanamid. 

CL92100 (terbufos): Validation of GC/FPD Determinative Methods M3153, 

M3154, M3155, and M 3156 For The Determination of CL 92100 Residues In, 

Respectively, Whole Body Dosimeters, Aerosol OT Handwash and Glove Wash 

Solutions, Air Sampling Tubes and Face/Neck Wipes; (3/26/99) Authored by 

Joseph Higham, Jill Cooper, and Rose Sweeney; Completed by ABC Laboratories 

of Columbia MO, and American Cyanamid of Princeton NJ.; Project ID #s 

include: Exhibit 4 of EPA MRID 447933-01, ABC Report 44703, and RES 99­

003, Sponsored by American Cyanamid. 

Occupational Exposure and Risk Assessment For Loaders and Applicators 

Handling Terbufos Products and Supporting Worker Exposure Studies; (3/26/99) 

Authored by Joseph Higham, Richard Honeycutt, D. Larry Merricks, Rose A. 

Sweeney, Cassi L. Walls, and Susan H Youngren; Completed by ABC 

Laboratories of Columbia MO, HERAC of Greensboro NC, Agrisearch of 

Frederick MD, Novigen Sciences of Washington DC, and American Cyanamid of 

Princeton NJ.; Project ID #s include: Exhibit 1 of EPA MRID 447933-01, 

Terbufos 99-02, EXA 99-004, EXA 99-006, and RES 99-003, Sponsored by 

American Cyanamid 

103
 
Appendix E. GENERIC DATA CALL-IN 

See table in docket for a list of generic data requirements. Note that a complete Data 

Call-In (DCI), with all pertinent instructions, is being sent to registrants under separate cover. 

104
 
Appendix F. PRODUCT SPECIFIC DATA CALL-IN 

See table in docket for a list of product-specific data requirements. Note that a complete 

Data Call-In (DCI), with all pertinent instructions, is being sent to registrants under separate 

cover. 

105
 
Appendix G.	 EPA’S BATCHING OF TERBUFOS PRODUCTS FOR MEETING 

ACUTE TOXICITY DATA REQUIREMENTS FOR 

REREGISTRATION 

In an effort to reduce the time, resources and number of animals needed to fulfill the 

acute toxicity data requirements for reregistration of products containing terbufos as the active 

ingredient, the Agency has batched products which can be considered similar for purposes of 

acute toxicity. Factors considered in the sorting process include each product's active and inert 

ingredients (identity, percent composition and biological activity), type of formulation (e.g., 

emulsifiable concentrate, aerosol, wettable powder, granular, etc.), and labeling (e.g., signal 

word, use classification, precautionary labeling, etc.). Note that the Agency is not describing 

batched products as "substantially similar" since some products within a batch may not be 

considered chemically similar or have identical use patterns. 

Using available information, batching has been accomplished by the process described in 

the preceding paragraph. Notwithstanding the batching process, the Agency reserves the right to 

require, at any time, acute toxicity data for an individual product should the need arise. 

Registrants of products within a batch may choose to cooperatively generate, submit or 

cite a single battery of six acute toxicological studies to represent all the products within that 

batch. It is the registrants' option to participate in the process with all other registrants, only 

some of the other registrants, or only their own products within a batch, or to generate all the 

required acute toxicological studies for each of their own products. If a registrant chooses to 

generate the data for a batch, he/she must use one of the products within the batch as the test 

material. If a registrant chooses to rely upon previously submitted acute toxicity data, he/she 

may do so provided that the data base is complete and valid by today's standards (see acceptance 

criteria attached), the formulation tested is considered by EPA to be similar for acute toxicity, 

and the formulation has not been significantly altered since submission and acceptance of the 

acute toxicity data. Regardless of whether new data is generated or existing data is referenced, 

registrants must clearly identify the test material by EPA Registration Number. If more than one 

confidential statement of formula (CSF) exists for a product, the registrant must indicate the 

formulation actually tested by identifying the corresponding CSF. 

In deciding how to meet the product specific data requirements, registrants must follow 

the directions given in the Data Call-In Notice and its attachments appended to the RED. The 

DCI Notice contains two response forms which are to be completed and submitted to the Agency 

within 90 days of receipt. The first form, "Data Call-In Response," asks whether the registrant 

will meet the data requirements for each product. The second form, "Requirements Status and 

Registrant's Response," lists the product specific data required for each product, including the 

standard six acute toxicity tests. A registrant who wishes to participate in a batch must decide 

whether he/she will provide the data or depend on someone else to do so. If a registrant supplies 

the data to support a batch of products, he/she must select one of the following options: 

Developing Data (Option 1), Submitting an Existing Study (Option 4), Upgrading an Existing 

Study (Option 5) or Citing an Existing Study (Option 6). If a registrant depends on another's 

data, he/she must choose among: Cost Sharing (Option 2), Offers to Cost Share (Option 3) or 

106
 
Citing an Existing Study (Option 6). If a registrant does not want to participate in a batch, the 

choices are Options 1, 4, 5 or 6. However, a registrant should know that choosing not to 

participate in a batch does not preclude other registrants in the batch from citing his/her studies 

and offering to cost share (Option 3) those studies. 

Three products were found which contain Terbufos as the active ingredient. These products 

have been placed into three batches in accordance with the active and inert ingredients and type 

of formulation. 

• The products in Batch 2 may be supported by citing/submitting the acute data from Batch 

1. 

• The products in Batch 3 may be supported by citing/submitting the acute data from Batch 

1. 

NOTE: The technical acute toxicity values included in this document are for informational 

purposes only. The data supporting these values may or may not meet the current acceptance 

criteria. 

Batch EPA Reg. No. % Active Ingredient Formulation Type 

1 241-241 85.0 Solid 

Batch EPA Reg. No. % Active Ingredient Formulation Type 

2 241-314 20.0 Solid 

Batch EPA Reg. No. % Active Ingredient Formulation Type 

3 241-238 15.0 Solid 

107
 
Appendix H. LIST OF REGISTRANTS SENT THIS DATA CALL-IN 

1) BASF Corporation 

108
 
Appendix I.	 LIST OF AVAILABLE RELATED DOCUMENTS AND 

ELECTRONICALLY AVAILABLE FORMS 

Pesticide Registration Forms are available at the following EPA internet site: 

http://www.epa.gov/opprd001/forms/. 

Pesticide Registration Forms (These forms are in PDF format and require the Acrobat reader) 

Instructions 

1.	 Print out and complete the forms. (Note: Form numbers that are bolded can be 

filled out on your computer then printed.) 

2.	 The completed form(s) should be submitted in hardcopy in accord with the

existing policy. 

3.	 Mail the forms, along with any additional documents necessary to comply with

EPA regulations covering your request, to the address below for the Document 

Processing Desk. 

DO NOT fax or e-mail any form containing 'Confidential Business Information' 

or 'Sensitive Information.' 

If you have any problems accessing these forms, please contact Nicole Williams 

at (703) 308-5551 or by e-mail at williams.nicole@epamail.epa.gov. 

The following Agency Pesticide Registration Forms are currently available via the internet: 

at the following locations: 

8570-1 Application for Pesticide 

Registration/Amendment 

http://www.epa.gov/opprd001/forms/8570-1.pdf. 

8570-4 Confidential Statement of Formula http://www.epa.gov/opprd001/forms/8570-4.pdf. 

8570-5 Notice of Supplemental Registration of 

Distribution of a Registered Pesticide Product 

http://www.epa.gov/opprd001/forms/8570-5.pdf. 

8570-17 Application for an Experimental Use Permit http://www.epa.gov/opprd001/forms/8570-17.pdf. 

8570-25 Application for/Notification of State 

Registration of a Pesticide To Meet a Special 

Local Need 

http://www.epa.gov/opprd001/forms/8570-25.pdf. 

8570-27 Formulator's Exemption Statement http://www.epa.gov/opprd001/forms/8570-27.pdf. 

109
 
8570-28 Certification of Compliance with Data Gap 

Procedures 

http://www.epa.gov/opprd001/forms/8570-28.pdf. 

8570-30 Pesticide Registration Maintenance Fee Filing http://www.epa.gov/opprd001/forms/8570-30.pdf. 

8570-32 Certification of Attempt to Enter into an 

Agreement with other Registrants for 

Development of Data 

http://www.epa.gov/opprd001/forms/8570-32.pdf. 

8570-34 Certification with Respect to Citations of Data 

(in PR Notice 98-5) 

http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf. 

8570-35 Data Matrix (in PR Notice 98-5) http://www.epa.gov/opppmsd1/PR_Notices/pr98-5.pdf. 

8570-36 Summary of the Physical/Chemical Properties 

(in PR Notice 98-1) 

http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf. 

8570-37 Self-Certification Statement for the 

Physical/Chemical Properties (in PR Notice 

98-1) 

http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf. 

Pesticide Registration Kit www.epa.gov/pesticides/registrationkit/. 

Dear Registrant: 

For your convenience, we have assembled an online registration kit which contains the

following pertinent forms and information needed to register a pesticide product with the U.S.

Environmental Protection Agency's Office of Pesticide Programs (OPP): 

1.	 The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal

Food, Drug and Cosmetic Act (FFDCA) as Amended by the Food Quality Protection

Act (FQPA) of 1996. 

2. Pesticide Registration (PR) Notices 

a. 83-3 Label Improvement Program--Storage and Disposal Statements 

b. 84-1 Clarification of Label Improvement Program 

c. 86-5 Standard Format for Data Submitted under FIFRA 

d.	 87-1 Label Improvement Program for Pesticides Applied through Irrigation

Systems (Chemigation) 

e. 87-6 Inert Ingredients in Pesticide Products Policy Statement 

f. 90-1 Inert Ingredients in Pesticide Products; Revised Policy Statement 

g. 95-2 Notifications, Non-notifications, and Minor Formulation Amendments 

h.	 98-1 Self Certification of Product Chemistry Data with Attachments (This

document is in PDF format and requires the Acrobat reader.) 

110
 
Other PR Notices can be found at http://www.epa.gov/opppmsd1/PR_Notices. 

3.	 Pesticide Product Registration Application Forms (These forms are in PDF format 

and will require the Acrobat reader.) 

a. EPA Form No. 8570-1, Application for Pesticide Registration/Amendment 

b. EPA Form No. 8570-4, Confidential Statement of Formula 

c. EPA Form No. 8570-27, Formulator's Exemption Statement 

d. EPA Form No. 8570-34, Certification with Respect to Citations of Data 

e. EPA Form No. 8570-35, Data Matrix 

4.	 General Pesticide Information (Some of these forms are in PDF format and will 

require the Acrobat reader.) 

a. Registration Division Personnel Contact List 

B. Biopesticides and Pollution Prevention Division (BPPD) Contacts 

C. Antimicrobials Division Organizational Structure/Contact List 

d.	 53 F.R. 15952, Pesticide Registration Procedures; Pesticide Data

Requirements (PDF format) 

e. 	 40 CFR Part 156, Labeling Requirements for Pesticides and Devices (PDF

format) 

f.. 40 CFR Part 158, Data Requirements for Registration (PDF format) 

g.. 50 F.R. 48833, Disclosure of Reviews of Pesticide Data (November 27,

1985) 

Before submitting your application for registration, you may wish to consult some 

additional sources of information. These include: 

1. The Office of Pesticide Programs' Web Site 

2.	 The booklet "General Information on Applying for Registration of Pesticides in the

United States", PB92-221811, available through the National Technical Information 

Service (NTIS) at the following address: 

National Technical Information Service (NTIS)
 

5285 Port Royal Road
 

Springfield, VA 22161 
 

The telephone number for NTIS is (703) 605-6000. Please note that EPA is currently

in the process of updating this booklet to reflect the changes in the registration

program resulting from the passage of the FQPA and the reorganization of the

Office of Pesticide Programs. We anticipate that this publication will become 

available during the Fall of 1998. 

3.	 The National Pesticide Information Retrieval System (NPIRS) of Purdue 

University's Center for Environmental and Regulatory Information Systems. This 

111
 
service does charge a fee for subscriptions and custom searches. You can contact 

NPIRS by telephone at (765) 494-6614 or through their Web site. 

4.	 The National Pesticide Telecommunications Network (NPTN) can provide

information on active ingredients, uses, toxicology, and chemistry of pesticides. You

can contact NPTN by telephone at (800) 858-7378 or through their Web site: 

ace.orst.edu/info/nptn. 

The Agency will return a notice of receipt of an application for registration or

amended registration, experimental use permit, or amendment to a petition if the

applicant or petitioner encloses with his submission a stamped, self-addressed 

postcard. The postcard must contain the following entries to be completed by OPP: 

Date of receipt 
 

EPA identifying number 
 

Product Manager assignment 
 

Other identifying information may be included by the applicant to link the

acknowledgment of receipt to the specific application submitted. EPA will stamp the

date of receipt and provide the EPA identifying File Symbol or petition number for 

the new submission. The identifying number should be used whenever you contact

the Agency concerning an application for registration, experimental use permit, or 

tolerance petition. 

To assist us in ensuring that all data you have submitted for the chemical are 

properly coded and assigned to your company, please include a list of all synonyms, 

common and trade names, company experimental codes, and other names which 

identify the chemical (including "blind" codes used when a sample was submitted 

for testing by commercial or academic facilities). Please provide a CAS number if 

one has been assigned. 

Documents Associated with this RED 

The following documents are part of the Administrative Record for this RED document and 

may included in the EPA's Office of Pesticide Programs Public Docket. Copies of these documents 

are not available electronically, but may be obtained by contacting the person listed on the 

respective Chemical Status Sheet. 

1. Health and Environmental Effects Science Chapters. 

2. Detailed Label Usage Information System (LUIS) Report. 

112