# 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.

Com b ined PDF docum ent consis ts o f the f o llowing:

• 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 I REDUNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460

OFFICE OF PR EVEN TION , PESTIC ID ES AN D TOXIC SU BSTAN C ES

MEMORANDUM

DATE: July 31, 2006

SUBJECT: Finalization of Interim Reregistration Eligibility Decisions (IREDs) and Interim Tolerance Reassessm ent and Risk Managem e nt Decisions (TREDs) for the Organophosphate Pesticides, and Com p letion of the Tolerance Reassessm ent and Reregistration Eligibility Process for the Organophosphate Pesticides

FROM: Debra Edwards, Director Special Review and Reregistration Division Office of Pesticide Program s

TO: Jim Jones, Director Office of Pesticide Program s

As you know, EPA has com p leted its assessm ent of the cum u lative 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 b een subject to review through the individualchem ical review process. The Agency’s review of individual OPs has resulted in the issuance of Interim Reregistration Eligibility Decisions (IREDs) f o r 22 OPs, interim Tolerance Reassessm ent and Risk Managem e nt Decisions (TREDs) for 8 OPs, and a Reregistration Eligibility Decision (RED) f o r one OP, m alathion. 1 These 31 OPs are listed in Appendix A.

EPA has concluded, after com p leting its assessm ent of the cum u lative 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

cum u lative assessm ent (listed in Attachm ent A) are indeed eligible f o r reregistration; and

1 Malathion is included in the OP cum u lative assessm ent. However, the Agency has issued a RED for m a lathion, rather than an IRED, because the decision was signed on the sam e day as the com p letion of the OP cum u lative

assessm ent.

Page 1 of 3(2) the pesticide tolerances covered by the IREDs and TREDs that were pending the results of the OP cum u lative assessm ent (listed in Attachm ent A) m eet the safety standard under Section 408(b)(2) of the FFDCA.

Thus, with regard to the OPs, EPA has f u lf illed its obligations as to FFDCA tolerance

reassessm ent and FIFRA reregistration, other than product-specific reregistration.

The Special Review and Reregistration Divisi on will be issuing data call-in notices f o r confirm atory data on two OPs, m ethidathion and phorate, for the reasons described in detail in the OP cum u lative assessm ent. The specif i c studies that will be required are:

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

− Drinking water m onitoring study for phorate, phorate sulfoxide, and phorate sulfone in both source water (at the intake) and treated water for five com m unity water system s in Palm Beach County, Florida and two near Lake Okechobee, Florida.

The cum u lative risk assessm ent and supporting docum ents are available on the Agency’s website

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

Page 2 of 3Attachment A: Organophosphates included in the OP Cum u lative Assessm ent

Chemical Decision Document Status
Acephate IRED IRED com p leted 9/2001 Azinphos-m ethy l (AZM) IRED IRED com p leted 10/2001 Bensulide IRED IRED com p leted 9/2000 Cadusafos TRED TRED com p leted 9/2000 Chlorethoxy phos TRED TRED com p leted 9/2000 Chlorpy r ifos IRED IRED com p leted 9/2001 Coum aphos TRED TRED com p leted 2/2000 DDVP (Dichlorvos) IRED IRED com p leted 6/2006 Diazinon IRED IRED com p leted 7/2002 Dicrotophos IRED IRED com p leted 4/2002 Dim e thoate IRED IRED com p leted 6/2006 Disulfoton IRED IRED com p leted 3/2002
Ethoprop IRED IRED com p leted 9/2001 IRED addendum com p leted 2/2006 Fenitrothion TRED TRED com p leted 10/2000 Malathion RED RED com p leted 8/2006 Metham idophos IRED IRED com p leted 4/2002 Methidathion IRED IRED com p leted 4/2002 Methy l Parathion IRED IRED com p leted 5/2003 Naled IRED IRED com p leted 1/2002 Oxy d em eton-m e thy l IRED IRED com p leted 8/2002 Phorate IRED IRED com p leted 3/2001 Phosalone TRED TRED com p leted 1/2001 Phosm e t IRED IRED com p leted 10/2001 Phostebupirim TRED TRED com p leted 12/2000 Pirim iphos-m ethy l IRED IRED com p leted 6/2001 Profenofos IRED IRED com p leted 9/2000 Propetam phos IRED IRED com p leted 12/2000 Terbufos IRED IRED com p leted 9/2001 Tetrachlorvinphos TRED TRED com p leted 12/2002 Tribufos IRED IRED com p leted 12/2000 Trichlorfon TRED TRED com p leted 9/2001

Page 3 of 3Septem ber 28, 2001

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES AND TOXIC S U BS TANCES

CERTIFIED MAIL

Dear Registrant:

This is to inform you that the Environm ental Protection Agency (hereafter referred to as EPA or the Agency) has com p leted its review of the available data and public com m e nts received related to the prelim inary and revised risk assessm ents for the organophosphate pesticide terbufos. The public com m e nt period on the revised risk assessm ent phase of the reregistration process is closed. Based on co m m e nts received during the public com m e nt period and additional data received from the registrant, the Agency revised the hum an health and environm ental effects risk assessm ents and m a de them available to the public on Septem ber 14, 1999. Additionally, the Agency held a Technical Briefing on Septem ber 2, 1999, where the results of the revised hum an health and environm ental effects risk assessm ents were presented to the general public. This Technical Briefing concluded Phase 4 of the OP Public Participation Pilot Process developed by the Tolerance Reassessm ent Advisory Com m ittee (TRAC), and initiated Phase 5 of that process. During Phase 5, all interested parties were invited to participate and provide com m e nts and suggestions on ways the Agency m i ght m itigate any estim ated risks presented in the revised risk assessm ents. This public participation and com m e nt period

com m e nced on Septem ber 14, 1999, and closed on Novem b er 12, 1999.

Based on its review, EPA has identified risk m a nagem e nt m easures that it believes are necessary to address the hum an health and environm ental risks associated with the current use of terbuf os. The EPA is now publishing its interim decision on the reregistration eligibility of and risk m a nagem e nt decision for the current uses of terbufos and its associated hum an health and environm ental risks. The reregistration eligibility and tolerance reassessm ent decisions f or terbufos will be finalized once the cum u lative risks for all of the organophosphate pesticides are considered. The enclosed “Interim Reregistration Eligibility Decision f o r Terbuf os,” which was approved on Septem ber 28, 2001, contains the Agency’s decision on the individual chem ical terbufos.

A Notice of Availability f o r this Interim Reregistration Eligibility Decision f o r terbuf os is being published in the Federal Register

. To obtain a copy of the interim RED docum ent, please contact the OPP Public Regulatory Docket (7502C), US EPA, Ariel Rios Building, 1200 Pennsylvania Avenue NW , W a shington, DC 20460, telephone (703) 305-5805. Electronic copies of the interim RED and all supporting docum ents are available on the Internet. See http:www.epa.gov/pesticides/op.The Interim RED is based on the updated technical inform ation found in the terbufos public docket. The docket not only includes background inform ation and com m e nts on the Agency’s prelim inary risk assessm ents, it also now includes the Agency’s revised risk

assessm ent for terbufos (revised as of Septem ber 14, 1999) , and a docum ent sum m a rizing the Agency’s Response to Com m e nts dated August 30, 1999. The Response to Com m e nts docum ent describes new studies subm itted by the chem ical registrant that were used to revise the risk assessm ents, and responds to com m e nts subm itted by the registrant, general public, and other stakeholders. The docket also includes com m e nts on the revised risk assessm ent, and any risk m itigation proposals subm itted during Phase 5. For terbufos, a risk m itigation proposal was subm itted by the chem ical registrant, BASF Corporation (f orm e rly Am erican Cyanam id).

This docum ent and the process used to develop it are the result of a pilot process to facilitate greater public involvem e nt and participation in the reregistration and/or tolerance

reassessm ent decisions for these pesticides. As part of the Agency’s effort to involve the public in the im plem entation of the Food Quality Protection Act of 1996 (FQPA) , the Agency is undertaking a special effort to m a intain open public dockets on the organophosphate pesticides and to engage the public in the reregistration and tolerance reassessm ent processes for these chem icals. This open process follows the guidance developed by the Tolerance Reassessm ent Advisory Com m ittee (TRAC), a large m u lti-stakeholder advisory body that advised the Agency on im plem enting the new provisions of the FQPA. The reregistration and tolerance reassessm ent reviews for the organophosphate pesticides are following this new process.

Please note that the terbufos risk assessm ent 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 reassessm ent. This interim RED presents the Agency’s conclusions on the dietary risks posed by exposure to terbufos alone. The Agency has also concluded its assessm ent of the ecological and work er risks associated with the use of terbufos. Because the FQPA directs the Agency to consider available inform ation on the basis of

cum u lative risk from substances sharing a com m on m echanism of toxicity, such as the toxicity expressed by the organophosphates through a com m on biochem i cal interaction with the cholinesterase enzym e , the Agency will evaluate the cum u lative risk posed by the entire organophosphate class of chem icals after considering the risks for the individual organophosphates. The Agency is working towards com p letion of a m e thodology to assess

cum u lative risk and the individual risk assessm ents for each organophosphate are likely to be necessary elem ents of any cum u lative assessm ent. The Agency has decided to m ove forward with individual assessm ents and to identify m itigation and risk m a nagem e nt m easures necessary to address those hum an health and environm ental risks associated with the current uses of terbuf os. The Agency will issue the f i nal tolerance reassessm ent decision f o r terbuf os and f i nalize decisions on reregistration eligibility once the cum u lative risks f o r all of the organophophates are considered.

This docum ent contains a generic and/or a product-specific Data Call-In(s) (DCI) that outline(s) f u rther data requirem e nts f o r this chem ical. Note that a com p lete DCI, with all pertinent instructions, is being sent to registrants under separate cover. Additionally, for product-specific DCIs, the first set of required respons es to is due 90 days from the receipt of the DCI letter. The second set of required responses is due eight m onths from the date of the DCI.In this interim RED, the Agency has determ ined that terbuf os will be eligible f or reregistration provided that all the conditions identified in this docum ent are satisfied, including im plem entation of the risk m a nagem e nt m easures outlined in Section IV of the docum ent. The Agency believes that current uses of terbufos m a y pose unreasonable adverse effects to hum an health and the environm ent, and that such effects can be adequately m a naged with the risk

m a nagem e nt m easures identified in this interim RED. Accordingly, the Agency recom m e nds that registrants im plem ent these risk m a nagem e nt m easures im m e diately. Sections IV and V of this interim RED describe labeling am endm ents for end-use products and data requirem e nts necessary to im plem ent these m itigation and risk reduction m easures. Instructions f o r registrants on subm itting the revised labeling can be found in the set of instructions for product-specific data that accom p anies this interim RED.

Should a registrant fail to im plem ent any of the risk m a nagem e nt m easures outlined in this docum ent, the Agency will continue to have concerns about the risks posed by terbufos. W h ere the Agency has identified any unreasonable adverse effect to hum an health and the environm ent, the Agency m a y at any tim e initiate appropriate regulatory action to address this concern. At that tim e, any affected person(s) m a y challenge the Agency’s action.

If you have questions on this docum ent or the label changes necessary for reregistration, please contact the Special Review and Reregi stration Division’s Chem ical Review Manager, Eric R. Olson at (703) 308-8067. For questions about product reregistration and/or the Product DCI that accom p anies this docum ent, please contact Karen Jones (703) 308-8047.

Sincerely

Lois A. Rossi, Director Special Review and

Reregistration Division

Attachm e nt

## Interim Reregistration Eligibility Decision for TERBUFOS

Case No. 0109TABLE 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

.................................... 1 0 A. Human Health Risk Assessment

...................................... 1 0 1. Dietary Risk from Food

........................................ 1 0

a. Toxicity

................................................ 1 1 b. FQPA Safety Factor

...................................... 1 1

c. Population Adjusted Dose (PAD)

........................... 1 2 d. Exposure Assumptions

.................................... 1 2

e. Food Risk Characteriz a tion

................................ 1 3 2. Dietary Risk from Drinking Water

.............................. 1 3

a. Surface Water

........................................... 1 4 b. Ground Water

........................................... 1 5

c. Drinking Water Levels of Comparison (DWLOCs)

............ 1 5 3. Aggregate Risk

............................................... 1 7 4. Occupational and Residential Risk

............................... 1 8

a. Toxicity

................................................ 1 8 b. Exposure

............................................... 2 0

c. Occupational Handler Risk Summary

....................... 2 2 1) Agricultural Handler Risk

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

............... 2 6 B. Environmental Risk Assessment

...................................... 2 6 1. Environmental Fate and Transport

.............................. 2 7

a. Degradation and Mobility

................................. 2 7 b. Field Dissipation

......................................... 2 8 2. Risk to Birds and Mammals

.................................... 2 8 3. Risk to Aquatic Species

........................................ 2 9

a. Aquatic LOC Assessment

................................. 2 9 b. Aquatic Incidents

........................................ 2 9 4. Endangered Species

........................................... 3 1

IV. Interim Risk Management and Reregistration Decision

....................... 3 1 A. Determination of Interim Reregistration Eligibility

...................... 3 1 B. Summary of Phase 5 Comments and Responses

......................... 3 3 C. Regulatory Position

................................................ 3 4 1. FQPA Assessment

............................................. 3 4

a. “Risk Cup” Determination

................................ 3 4 b. Tolerance Summary

...................................... 3 52. Endocrine Disruptor Effects

.................................... 3 8 3. Labels

....................................................... 3 8

a. Agricultural Use Exposure Reduction Measures

.............. 3 8 b. Homeow ner Use Exposure Reduction Measures

............... 3 9 D. Regulatory Rationale

............................................... 3 9 1. Human Health Risk Mitigation

.................................. 3 9

a. Dietary Mitigation

....................................... 3 9 1) Acute Dietary (Food)

........................... 3 9 2) Chronic Dietary (Food)

......................... 4 0 3) Drinking Water

................................ 4 0 b. Occupational Risk Mitigation

.............................. 4 1 1) Agricultural Uses

.............................. 4 1 2) Post-Application Risk

........................... 4 3

c. Homeow ner Risk Mitigation

............................... 4 3 2. Environmental Risk Mitigation

................................. 4 4 3. Benefits Assessment

........................................... 4 4 E. Other Labeling

.................................................... 4 5 1. Endangered Species Statement

.................................. 4 5

V. What Registrants Needs to Do

............................................ 4 6 A. Manufacturing Use Products

........................................ 4 8 1. Additional Generic Data Requirements

........................... 4 8 2. Labeling Requirements for Manufacturing Use Products

............ 4 8 B. End-Use Products

.................................................. 4 8 1. Additional Generic Data Requirements

........................... 4 8 2. Labeling Requirements for End-Use Products

..................... 4 9 C. Existing Stocks

.................................................... 4 9 D. Required Labeling Changes Summary Table

........................... 5 0

VI. R elated Documents and How to Access Them

............................... 6 1

VI. APPENDICES

......................................................... 6 2 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

..................................... 6 3

USED TO MAKE THE REREGISTRATION DECISION

...... 6 8 Appendix C. TECHNICAL SUPPORT DOCUMENTS

.................... 7 8

(BIBLIOGRAPHY)

...................................... 8 0 Appendix E. GENERIC DATA CALL-IN

.............................. 1 04 Appendix F. PRODUCT SPECIFIC DATA CALL-IN

.................... 1 05

REREGISTRATION

.................................... 1 06 Appendix H. LIST OF REGISTRANTS SENT THIS DATA CALL-IN

...... 1 08 LIST OF AVAILABLE RELATED DOCUMENTS AND Appendix I. ELECTRONICALLY AVAILABLE FORMS

............... 1 09TERBUFOS TEAM

Health Effects Risk Assessm ent Jeffery Dawson W illiam Hazel Michael Metzger Christina Swartz

Environm ental Fate (Drinking W a ter and Ecological) Risk Assessm ent Thom as Bailey Jam e s Breithaupt Jam e s Carleton David Farrar

Use and Usage Analysis Donald Atwood David Brassard

Registration Support Marilyn Mautz

Risk Managem e nt Pam Noyes Eric R. Olson Mark Hartm a n

### GLOSSARY OF TERMS AND ABBREVIATIONS

AE Acid Equivalent a.i. Active Ingredient AGDCI A gricultural Data Call-In ai Active Ingredient aPAD Acute Population Adjusted Dose AR Anticipated Residue ARC Anticipated Residue Contribution BCF Bioconcentration Factor CAS C hem i cal Abstracts Service CI Cation CNS C entral Nervous System cPAD Chronic Population Adjusted Dose CSF C onf idential Statem ent of Form ula CFR C ode of Federal Regulations CSFII U SDA Continuing Surveys for Food Intake by Individuals DCI D ata Call-In DEEM Dietary Exposure Evaluation Model DFR D islodgeable Foliar Residue DRES Dietary Risk Evaluation System DW EL Drinking W a ter Equivalent Level (DW EL) The DW EL represents a m e dium specific (i.e., drinking water) lifetim e exposure at which adverse, noncarcinogenic health effects are not anticipated to occur. DW LOC D rinking W a ter Level of Com p arison. EC Em ulsifiable Concentrate Form ulation EEC Estim ated Environm ental Concentration. The estim ated pesticide concentration in an environm ent, such as a terrestrial ecosystem

. EP End-Use Product EPA U .S. Environm ental Protection Agency FAO F ood and Agriculture Organization FDA F ood and Drug Adm i nistration FIFRA F ederal Insecticide, Fungicide, and Rodenticide Act FFDCA Federal Food, Drug, and Cosm etic Act FQPA Food Quality Protection Act FOB F unctional Observation Battery G G ranular Form ulation GENEEC Tier I Surface W a ter Com puter Model GLC G as Liquid Chrom a tography GLN G uideline Num b er GM Geom etric Mean GRAS Generally Recognized as Safe as Designated by FDA HA Health Advisory (HA). The HA values are used as inform al guidance to

m

unicipalities and other organizations when em ergency spills or contam ination situations occur. HAFT H ighest Average Field Trial HDT Highest Dose Tested IR Index ReservoirLC 50 Median Lethal Concentration. A statistically derived concentration of a substance that can be expected to cause death in 50% of test anim als. It is usually expressed as the weight of substance per weight or volum e of water, air or feed, e.g., m g /l,

m g /kg or ppm

. LD 50 Median Lethal Dose. A statistically derived single dose that can be expected to cause death in 50% of the test anim als when adm i nistered by the route indicated (oral, derm al, inhalation). It is expressed as a weight of substance per unit weight of anim al, e.g., m g /kg. LEL Lowest Effect Level LOC L evel of Concern LOD L im it of Detection LOAEL L owest Observed Adverse Effect Level MATC Maxim um Acceptable Toxicant Concentration MCLG Maxim um Contam inant Level Goal (MCLG) The MCLG is used by the Agency to regulate contam inants in drinking water under the Safe Drinking W a ter Act.

m g /kg/day M illigram Per Kilogram Per Day

m g /L Milligram s Per Liter MOE M argin of Exposure MP Manufacturing-Use Product MPI M axim um Perm issible Intake MRID Master Record Identification (num ber). EPA' s system of recording and tracking studies subm itted. NA Not Applicable N/A N ot Applicable NAW QA USGS National W a ter Quality Assessm ent NOEC N o Observable Effect Concentration NOEL N o Observed Effect Level NOAEL N o Observed Adverse Effect Level NPDES N ational Pollutant Discharge Elim ination System NR Not Required OP Organophosphate OPP E PA Office of Pesticide Program s OPPTS E PA 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 m e ter. PAD P opulation Adjusted Dose PADI Provisional Acceptable Daily Intake PAG P esticide Assessm ent Guideline PAM P esticide Analytical Method PCA P ercent Crop Area PDP U SDA Pesticide Data Program PHED Pesticide Handler' s Exposure Data PHI P reharvest Interval ppb Parts Per Billion PPE Personal Protective Equipm ent ppm Parts Per Million PRN P esticide Registration Notice PRZM/EXAMS T ier II Surface W a ter Com puter Model Q 1 * T he Carcinogenic Potential of a Com pound, Quantified by the EPA' s Cancer Risk Model RAC R aw Agriculture Com m odity RBC Red Blood Cell RED R eregistration Eligibility Decision REI R estricted Entry Interval RfD R eference Dose RQ Risk Quotient RS Registration Standard RUP R estricted Use Pesticide SAP S cience Advisory Panel SCI-GROW T ier I Ground W a ter Com puter Model SF Safety Factor SLC S ingle Layer Clothing SLN S pecial 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 Chrom a tography TMRC Theoretical Maxim um Residue Contribution
torr A unit of pressure needed to support a colum n of m e rcury 1 m m high under standard conditions. TRR T otal Radioactive Residue UF Uncertainty Factor

F g/g M icrogram s Per Gram

F g/L M icrogram s Per Liter USDA United States Departm e nt of Agriculture USGS United States Geological Survey UV Ultraviolet W H O W orld Health Organization WP We t t a bl e P ow de r W P S W orker Protection StandardExecutive Summary

EPA has com p leted its review of public com m e nts on the revised risk assessm ents and is issuing its interim risk m a nagem e nt decisions f o r terbuf os. The decisions outlined in this docum ent do not include the final tolerance reassessm ent decision for terbufos. At this tim e, no tolerance actions are necessary for terbufos. The final tolerance reassessm ent decision for this chem ical will be issued once the cum u lative risks for all of the organophosphates are considered. The Agency m a y need to pursue further risk m a nagem e nt m easures for terbufos once cum u lative risks are considered.

The revised risk assessm ents are based on review of the required target data base supporting the use patterns of currently registered products and new inform ation received. The Agency invited stakeholders to provide proposals, ideas or suggestions on appropriate m itigation

m easures bef o re the Agency issued its risk m itigation decision on terbuf os. Af ter considering the revised risks, as well as m itigation proposed by BASF the technical registrant of terbufos, and com m e nts and m itigation suggestions from other interested parties, including the states of North Carolina and Indiana, Defenders of W ildlif e, several property owners, growers and grower organizations, and agricultural extension agents, EPA developed its risk m a nagem e nt decision for uses of terbufos that pose risks of concern. This decision is discussed fully in this docum ent.

Terbufos is an organophosphate insecticide-nem a ticide 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 dom estic use of approxim a tely 7.5 m illion pounds of active ingredient per year during that period.

Overall Risk Sum m a ry

EPA’s hum an health risk assessm ent for terbufos indicates som e risk concerns. Food risk, both acute and chronic, is below the Agency’s level of concern. Drinking water risk estim ates based on m odels, from both ground and surface water for acute and chronic exposures, is of concern for m o st populations, notably infants and children. Even when potential food exposures to terbufos are not considered, m odeled concentr ations of terbufos in groundwater and surface water alone exceed the Agency’s level of acute and chronic dietary risk concern based on Estim ated Environm ental Concentrations (EEC’s). The Agency also has som e risk concerns for handlers who handle terbufos in open bag/open cab and closed system s (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/hom eowner exposures.

EPA’s environm ental risk assessm ent for terbufos indicates risk concerns to non-target organism s. The Agency is particularly concerned about risks to aquatic species, based on the Agency’s aquatic assessm ent, and supported by fish kill incidents associated with the use of terbufos on corn.

To m a nage risks of concern posed by the uses of terbufos, EPA considered the risk

1m a nagem e nt proposal subm itted by the technical registrant, as well as com m e nts and ideas from other interested parties, and has decided on a num ber of label am endm ents to address the ecological, drinking water, and worker risk concerns. Results of the risk assessm ents, and required label am endm ents to m a nage 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 m odeled drinking water exposures are added to the acute and chronic dietary risk assessm ent. Drinking water risks of concern are expected to be m a naged by the steps outlined in the discussion of ecological risk explained below.

Occupational Risk

Occupational exposures to terbufos are not a risk concern for m o st 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 determ ined that risk concerns for Counter 15G can be m itigated to acceptable levels if applications are restricted to closed cab tractors and the m a xim um application rate on sorghum is reduced. For the Counter 20CR open bag product, risk concerns on sorghum can also be m itigated to an acceptable level if there is a reduction in the m a xim um 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 m a xim um application rate of the Section 3 registration. The Agency has determ ined that this risk concern can be m itigated to an acceptable level if North Carolina revises the SLN registration to perm it use of Counter 20CR in closed loading sy stem s 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 m e thods, tim ing, and frequency. The Agency concludes that the 48 hour Restricted Entry Interval (REI) established under EPA’s W o rker Protection Standards (W PS) is sufficient to protect workers who m a y re-enter treated areas. Therefore, with the addition of the label restrictions and am endm ents detailed in this docum ent, the Agency has determ ined that, until the outcom e of the cum u lative risk assessm ent f o r all of the organophosphates has been decided, all currently registered uses of terbufos m a y continue.

Ecological Risk

Ecological risks to terrestrial and aquatic organism s are of concern to the Agency. The Agency is concerned about potential adverse effects to terrestrial and aquatic organism s, based on the Agency’s assessm ent and f i sh kills associated with the use of terbuf os on corn. Aquatic incidents reported to EPA indicate that terbuf os is the leading cause of f

i sh kills am ong pesticides applied to corn, and is f ourth in causing f i sh kills f o r any pesticide applied to any crop.

2The Agency has determ ined that these risks can be reduced by im plem enting lim itations on sales of terbufos and adding buffers to the labels. The registrant has agreed to a phased approach that will ultim ately reduce sales of terbufos by 55% by 2008 based on 2000 sales figures. By reducing the total am ount of terbufos available to be applied, the Agency expects that risks to aquatic and terrestrial organism s will be reduced.

The buffers to be im plem ented are; 1) a 500 ft. vegetative buffer between treated area and surface water on neighboring land, 2) a 500 ft. vege tative 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 erodi ble 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 equipm ent within 300 ft. fr om surface water bodies or within 50 ft. from wells unless conducted on an im pervious surface. All setbacks m u st be planted to a crop or seeded with grass or other suitable cover.

In addition, the registrant has agreed to voluntarily rem ove from its labels the “over the top” application on corn f o r 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 inc h. To prevent the flow of rainfall down planted rows, the label text will read “To prevent channe ling of surface water run-off, adjust the planter row-cleaners appropriately to prevent rows lower in height than adjacent soil”.

Benef its

The benefits of terbufos on corn were estim ated using a com p arative product perform a nce assessm ent. This assessm ent aim e d at quantifying, to the extent possible, the benefits derived from the use of terbufos on corn prim arily for control of corn rootworm

. It relied on data from num erous product perform a nce studies available in the open scientific literature. These data were analyzed using statistical m e thods to determ ine the relative effects on corn yields of using terbufos and other corn insecticides especially tefluthrin. The benefits

assessm ent concluded that under m o st conditions the alternative insecticides produced sim ilar 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 perform e d m o re effectively on som e secondary corn pests. However, there are uncertainties associated with the assessm ent that were taken into consideration when developing the risk m a nagem e nt m easures outlined in the IRED.

For the uses of terbufos the Agency has dete rm ined that, with the adoption of all of the label am endm ents noted in this docum ent, use m a y continue until the outcom e of the cum u lative

assessm ent of all of the organophosphates has been decided.

The Agency is issuing this interim Reregistration Eligibility Docum e nt (RED) f or terbufos, as announced in a Notice of Availability published in the Federal Register

. This

3interim RED docum ent includes guidance and tim e fram es for com p lying with any necessary label changes for products containing terbufos. There is a 60-day public com m e nt period for this docum ent to allow stakeholders the opportunity to review and provide com m e nts on this docum ent. W ith regard to com p lying with the requirem e nts in this docum ent, the Agency has shortened this tim e period so that the risks identif ied herein are m itigated as quickly as possible. Neither the tolerance reassessm ent nor the reregistration eligibility decision f o r terbuf os can be considered final, however, until the cum u lative risks for all organophosphate pesticides are considered. The cum u lative assessm ent m a y result in f u rther required risk m itigation m easures for terbufos.

4I. Introduction

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was am ended in 1988 to accelerate the reregistration of products with active ingredients registered prior to Novem b er 1, 1984. The am ended Act calls for the developm ent and subm ission of data to support the reregistration of an active ingredient, as well as a review of all subm itted data by the U.S. Environm ental 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 determ ine the need for additional data on health and environm ental effects; and to determ ine whether the pesticide m eets 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 am ends FIFRA to require tolerance reassessm ent of all existing tolerances. The Agency had decided that, for those chem icals that have tolerances and are undergoing reregistration, the tolerance reassessm ent will be initiated through this reregistration process. It also requires that by 2006, EPA m u st review all tolerances in effect on the day before the date of the enactm e nt of the FQPA, which was August 3, 1996. FQPA also am ends the FFDCA to require a safety finding in tolerance reassessm ent based on factors including an assessm ent of

cum u lative effects of chem icals with a com m on m echanism of toxicity. Terbufos belongs to a group of pesticides called organophosphates, which share a com m on m echanism of toxicity ­ they all affect the nervous system by inhibiting cholinesterase. Although FQPA significantly affects the Agency’s reregistration process, it does not am end any of the existing reregistration deadlines. Therefore, the Agency is continuing its reregistration program while it resolves the

rem a ining issues associated with the im plem entation of FQPA.

This docum ent presents the Agency’s revised hum an health and ecological risk

assessm ents; its progress toward tolerance reassessm ent; and the interim decision on reregistration eligibility f o r terbuf os. It is intended to be only the f i rst phase in the reregistration process for terbufos. The Agency will eventually proceed with its assessm ent of the cum u lative risk of the OP pesticides and issue a f i nal reregistration eligibility decision f o r terbuf os.

The im plem entation of FQPA has required th e Agency to revisit som e of its existing policies relating to the determ ination and regulation of dietary risk, and has also raised a num ber of new issues for which policies need to be cr eated. These issues were refined and developed through collaboration between the Agency and the Tolerance Reassessm ent Advisory Com m ittee (TRAC), which was com posed of representatives from industry, environm ental groups, and other interested parties. The TRAC identif ied the f o llowing science policy issues it believed were key to the im plem entation of FQPA and tolerance reassessm ent:

• A pplying the FQPA 10-Fold Safety Factor

• W hether and How to Use "Monte Carlo" Analyses in Dietary Exposure Assessm ents

• H ow to Interpret "No Detectable Residues" in Dietary Exposure Assessm ents

5• R efining Dietary (Food) Exposure Estim ates

• R efining Dietary (Drinking W a ter) Exposure Estim ates

• A ssessing Residential Exposure

• A ggregating Exposure from all Non-Occupational Sources

• H ow to Conduct a Cum u lative Risk Assessm ent for Organophosphate or Other Pesticides with a Com m on Mechanism of Toxicity

• S election of Appropriate Toxicity Endpoint s for Risk Assessm ents of Organophosphates

• W hether and How to Use Data Derived from Hum a n Studies

The process developed by the TRAC calls for EPA to provide one or m o re docum ents for public com m e nt on each of the policy issues described above. Each of these issues is evolving and in a different stage of refinem e nt. Som e issue papers have already been published for

com m e nt 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 (P R 2000-9) that presents EPA’s approach for

m a naging risks from organophosphate pesticides to occupational users. The W o rker PR Notice describes the Agency’s baseline approach to m a naging risks to handlers and workers who m a y be exposed to organophosphate pesticides, and the Agency expects that other types of chem icals will be handled sim ilarly. Generally, basic protective m easures such as closed m i xing and loading system s, enclosed cab equipm ent, or protective clothing, as well as increased reentry intervals will be necessary for m o st uses where current risk assessm ents indicate a risk and such protective m easures are f easible. The policy also states that the Agency will assess each pesticide individually, and based upon the risk assessm ent, determ ine the need for specific

m easures tailored to the potential risks of the chem ical. The m easures included in this interim RED are consistent with the W o rker Pesticide Registration Notice.

This docum ent consists of six sections. Section I contains the regulatory fram ework for reregistration/tolerance reassessm ent as well as descriptions of the process developed by TRAC for public com m e nt on science policy issues for the organophosphate pesticides and the worker risk m a nagem e nt PR notice. Section II provides a profile of the use and usage of the chem ical. Section III gives an overview of the revised hum an health and environm ental effects risk

assessm ents resulting from public com m e nts and other inform ation. Section IV presents the Agency' s interim reregistration eligibility and risk m a nagem e nt decisions. Section V

sum m a rizes required label changes based on the risk m itigation and risk reduction m easures outlined in Section IV. Section VI provides inform ation on how to access related docum ents. Finally, the Appendices lists Data Call-In (DCI) inform ation. The revised risk assessm ents and related addenda are not included in this docum ent, but are available on the Agency' s web page www.epa.gov/pesticides/op, and in the Public Docket.

6II. Chemical Overview

A. Regulatory History

Terbufos was first registered in the United States in 1974 by EPA for use as a system ic insecticide-nem a ticide 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 num erous studies to support continued registration. The 1983 Registra tion standard was am ended in February 1985 to require Restricted Use classification due to acute oral and derm al toxicity. Two Prelim inary 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 organism s; birds, m a m m a ls, aquatic species, and endangered species.

B. Chemical Identification

Chemical Structure of Terbufos:

! Common Name: Terbufos

! Chemical Name: S-[[1,1-dim e thylethyl) thio] O,O-di-ethyl phosphorodithioate

! Chemical family: Organophosphate

! CAS registry number: 13071-79-9

! OPP chemical code: 105001

! Empirical formula: C 9 H 21 O 2 PS 3

! Molecular w e ight: 288.4

! Trade and other names: Counter®

! Basic manufacturer: BASF Corporation (technical registrant)

7Technical terbufos is a colorless to pale yellow clear liquid with a m e rcaptan-like odor. It has a boiling point of 55 E C at 0.02 m m Hg, and a density of 1.11 g/m l at 20 E C. The solubility of terbuf os in water at 25 E C is 5.4 ppm

. Its solubility in acetone, acetonitrile, benzene, chloroform , dichlorom e thane, ethanol, n-heptane, m e thylene chloride, and toluene is reported as $ 100 g/100 m l at 20 E C. W a ter solubilities of the two m a jor soil/water degradates at 25 E C are 3214 m g /L and 407 m g /L for terbufos sulfoxide and terbufos sulfone, respectively.

C. Use Profile

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

Type of Pesticide: System ic insecticide-nem a ticide

Summary of Use Sites:

Food : Terbufos is applied at-plant/at-bedding, post em ergent, or at cultivation to control m a ny types of insect pests. Registered use sites are corn (field, sweet, and pop), sugarbeets, and grain sorghum

. Approxim a tely 80 percent of terbufos is applied to field corn. Terbufos is also used on im ported bananas grown in South Am erica and Mexico.

Residential : None.

Public Health : None.

Other Nonfood : None.

Target Pests: Target pests include corn rootworm s, wireworm s, white grubs, billbugs, sugarbeet root m a ggots, cutworm s , and nem a todes.

Formulation Types Registered : In addition to the technical, there are two enduse form ulations registered: a clay-based granular form ulation and a polym eric granular form ulation.

Method and Rates of Application :

Equipm ent - Granular row planters; in front of planter’s press wheel with light soil incorporation using, for exam ple, drag chains, tines, or cultivators.

Method and Rate - Applied 1) at-plant/at-bedding (banded, in-furrow, knifed-in); 2) post em ergent (banded alongside plant); and 3) at cultivation. All applications require soil incorporation.

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

m a xim um application rate for corn is 1.3 lbs a.i./A, applied one tim e 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 tim e per year.

• T he typical application rate for sugarbeets is 1.3 lbs a.i./A and for sorghum is 0.7 lbs a.i./A, both lim ited to one application per year. The m a xim um application rate on these crops is 1.96 lbs a.i./A, applied one tim e per year.

Tim i ng - At-plant/at-bedding, post-em ergent, at-cultivation

Use Classification: The registered terbufos end-use products are restricted use products due to acute oral and derm al toxicity.

D. Estimated Usage of Pesticide

This section sum m a rizes the best estim ates available for m a ny of the pesticide uses of terbufos, based on available pesticide usage inform ation for 1987 to 1996. A full listing of all uses of terbufos, with the corresponding use and usage data for each site, has been com p leted and is in the “Quantitative Use Assessm ent” docum ent, 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 f r om various inf o rm ation sources. Approxim a tely 7.5 m illion pounds of Terbufos a.i. are used annually, according to Agency estim ates.

Table 1. Terbufos Estimated Usage

Cro p Lb s. Activ e Ingredi e nt Appl i e d (W t

. Avg.) 1 Percent Crop Treated (Likely M a x i mu m) Percent Crop Treated (W t. Avg.)

C o rn (fi el d, pop) 6,530,000 10% 8%

Sugar B eet s 670,000 43% 35%
Sorghum 190,000 4% 2%

Sweet C o rn 55,000 6% 5%

1 W e ighted Average is based on data fo r 1987-1996; the m o st recent years and m o re reliable data are weighted m o re heavily.

The registrant has provided the Agency with proprietary dom estic sales figures for 2000. It should be noted that while these figures are significantly lower than the Agency estim ates presented in the table above, the proportions am ong the crops are com p arable.

III. Summary of Terbufos Risk Assessments

9Following is a sum m a ry of EPA’s revised hum an health and ecological risk findings and conclusions for the organophosphate pesticide terbufos, as fully presented in the docum ents, “Terbufos, Hum a n Health Risk Assessm ent” dated Septem ber 2, 1999, and “Terbufos, Revised EFED Reregistration Eligibility Decision (RED ) Chapter,” dated August 26, 1999. The purpose of this sum m a ry is to assist the reader by iden tifying the key features and findings of these risk

assessm ents, and to better understand the conclusions reached in the assessm ents.

These risk assessm ents for terbufos were presented at a Septem ber 2, 1999, Technical Briefing, which was followed by an opportunity for public com m e nt on risk m a nagem e nt. The risk assessm ents presented here form the basis of the Agency’s interim risk m a nagem e nt decision for terbufos only; the Agency m u st consider cum u lative risks of all the organophosphate pesticides before any final decisions can be m a de.

A. Human Health Risk Assessment

EPA issued its prelim inary risk assessm ents for terbufos in August 1998 (Phase 3 of the TRAC process). In response to com m e nts and studies subm itted during Phase 3, the risk

assessm ents were refined and updated. Major revisions to the hum an health risk assessm ent are listed below:

– U se of new acute and subchronic oral rat neurotoxicity studies in the acute and chronic dietary risk assessm ents.

– R eduction 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.

– U se of new corn and banana residue field tr ial studies in the acute and chronic dietary risk assessm ents, in com b ination with previously subm itted f i eld trial data.

– U se of new chem ical specific worker expos ure studies and form ulation-specific 28-day rat derm al toxicity studies in the occupational risk assessm ent.

– U se of separate toxicological endpoints for derm al and inhalation exposures for the occupational assessm ent.

– Use of the SCI-GROW and PRZM-EXAMS m odels and new aquatic m e tabolism data to estim ate potential environm ental concentrations (EECs) of terbufos in drinking water through groundwater and surface water.

1. Dietary Risk from Food

a. Toxicity

10The Agency has reviewed all toxicity studies subm itted and has determ ined that the toxicity database is sufficiently com p lete, and that it supports an interim reregistration eligibility determ ination for all currently registered uses. Further details on the toxicity of terbufos can be found in the Septem ber 2, 1999 Hum a n Health Risk Assessm ent. A brief overview of the studies used f o r the dietary risk assessm ent is outlined in Table 2 in this docum ent.

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 terbuf os. 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 m ouse 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 m o tor activity, but several functional observational battery (FOB) param e ters (e.g., ataxia, decreased forelim b grip strength, trem ors) were affected. No treatm e nt-related effects were observed on m o tor activity or in the FOB param e ters m easured in the rat subchronic neurotoxicity study. In the developm ental and reproduction studies, effects we re observed in fetuses/offspring only at or above treatm e nt levels, which resulted in evidence of parental toxicity. The dietary food
exposure assessm ent does not underestim ate potential exposures to infants and children from terbufos residues in food. No exposure is expected to infants and children fromresidential (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.

Ex po sure Scenario Dose (mg/ kg/ d ay) Endpoint S tudy UF FQPA Safety Factor PAD (mg/ kg/ d ay)

Acute Dietary NOAEL = 0.15 Plasma ChE inhibition in both sexes and clinica l sig n s. Acute Oral Neurotoxi ci ty i n Rats (MRID 44672003) 500 1X 0.0003 mg/kg/day

Chronic Dietary NOAEL = 0.005 Plasma ChE inhibition in both sexes. Chroni c 1-year and subchroni c oral toxi ci ty i n dog (MRIDs 00263678, 40374701) 100 1X 0.00005 mg/kg/day

11c. Population Adjusted Dose (PAD)

The PAD is a term that characterizes the dietary risk of a chem ical, 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 estim ate 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 m g/ kg/day (0.15 m g /kg/day/500) based on plasm a ChE and clinical signs observed in the acute rat neurotoxicity study. The UF of 500 is calculated as f o llows: 10X f o r interspecies extrapolation x 10X f o r intraspecies variability x 5X f or differences in sensitivity between rats and dogs. The additional UF of 5X is required based on an analysis of plasm a ChE in the rat subchroni c neurotoxicity study and a 28-day oral toxicity study in dogs. The analysis was perform e d to determ ine a species sensitivity factor that would be appropriate to apply to the rat acute neurot oxicity study. Previously, EPA had selected results from the 28-day dog toxicity study for the acute endpoint, which had a plasm a ChE m easurem ent at day 7. Using the rat acute neurotoxicity study for the endpoint with a derived species sensitivity factor provides the appropriate tim e-related endpoint and takes into account the observed sensitivity between the rat and dog.

The chronic PAD for terbufos is 0.00005 m g /kg/day (0.005 m g /kg/day ÷ 100) based on plasm a ChE observed in a 28-day oral toxic ity study in dogs (NOAEL = 0.005 m g /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 consum ption 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 fi eld trial studies, and weighted average percent crop treated figures. The dietary exposure anal yses for terbufos are based largely on residue values f r om f

i eld trial data below the lim it of detection (LOD), between the LOD and lim it of quantitation (LOQ), or at the LOQ. The Agency considered using m onitoring data f r om USDA’s Pesticide Data Program (PDP) and FDA enforcem ent m onitoring data available for terbufos on bananas and sweet corn, but determ ined that these data are not appropriate for use in this risk assessm ent for several reasons, including that the m onitoring effort did not m easure all the terbufos degradates of concern. It should also be noted that exposure from coffee beans treated with terbufos was included in the dietary assessm ent because a proposal to extend the tim e-lim ited tolerance f o r that com m odity is currently pending.

12e. Food Risk Characteriz a tion

Generally, a dietary risk estim ate that is less than 100% of the acute or chronic Population Adjusted Dose does not exceed EPA’s ri sk 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 exam ple, for the m o st 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 consum ption of food alone.

The chronic dietary risk from food alone is well below the Agency’s level of concern. For the m o st exposed subgroups, infants, the percent chronic PAD values are no m o re 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 m o st significant contributor to the estim ated acute dietary risk from food alone. Both the acute and chronic dietary risk assessm ents 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 cor n, since there are no chem ical-specific cooking studies available. EPA could refine the terbuf os dietary exposure analysis if these data were generated and could be further refined if appropria te m onitoring data were available. It should be noted that the available PDP m onitoring data, while not appropriate for the purposes of quantitative risk assessm ent, found no detections of terbufos or terbufos sulfone residues in over 100 sam p les of sweet corn. Any and all available refinem e nts will be considered when the

cum u lative assessm ent 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
contam ination. EPA considers both acute (one da y) and chronic (lifetim e) drinking water risks and uses either m odeling or actual m onitoring data, if available, to estim ate those risks. Modeling is considered to be an unrefined assessm ent and provides a high-end estim ate of risk.

The GENEEC and PRZM-EXAMS m odels were used to estim ate surface water concentrations, and SCI-GROW was used to estim ate groundwater concentrations. All of these are considered to be screening m odels, with the PRZM-EXAMS m odel being som e what m o re refined than the other two.

In the case of terbufos, EPA is concerned about the potential for parent terbufos and its
two m a jor 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 m odel was used to estim ate surface water concentrations, and SCI-GROW was used to estim ate groundwater concentrations. Although som e m onitoring data for terbufos were

13available, these data were deem ed of lim ited value for several reasons, including that the degradates of concern were typically not include d as part of the analyses. Further discussion follows below regarding the m onitoring data the Agency considered for terbufos. EPA also reviewed and considered new environm ental fate data subm itted on the abiotic hydrolysis and aerobic aquatic m e tabolism of parent terbufos and its degradates.

a. Surface Water

The Tier II PRZM-EXAMS screening m odel is used to estim ate upper-bound environm ental concentrations (EECs) in drinking water derived from surface water. This m odel, in general, is based on m o re refined, less conservative assum p tions than the Tier I GENEEC screening m odel. Acute m odeled 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 m odeled 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 im plem ented Index Reservoir (IR) and Percent Crop Area (PCA) m odifications to the Tier II PRZM-EXAMS m odel to calculate upper-bound EECs for terbufos and its degradates in drinking wa ter derived from surface water. Applying the IR and PCA m odifications, acute m odeled EECs for te rbufos 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 m odeled 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 m odel assum e s terbufos applications are m a de at the m a xim um rate for each crop on the current label, using the labeled m e thods of application (i.e., T-banded, infurrow, or knifed-in). In addition, the Agency applied the standard assum p tion 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 m odel were derived using direct m easurem ents of terbufos parent and its degradates from aerobic aquatic m e tabolism data (MRID 44862502), rather than default or “worst-case” assum p tions, which provides additional refinem e nt to the terbufos m odeling.

Monitoring for terbufos in surface water is lim ited and has been undertaken by U.S. Geological Survey (USGS) in its National W a ter Quality Assessm ent (NAW QA) program and by som e states. Terbufos parent was not found above 2.25 ppb in m onitoring data. The Agency believes that the terbufos m onitoring data available are lim ited and often not associated with periods of terbufos use. For instance, sam p les were often taken throughout the year rather than concentrating sam p ling during the tim e period when terbufos application is expected. Furtherm ore, the degradates of concern, terbufos sulfoxide and sulfone, were not included in any of the analyses. Given these lim itations, the existing surface water m onitoring database cannot be used to estim ate concentrations of terbufos in surface water. However, the Agency notes that the available NAW QA data found 17 detections of parent terbufos in 5,198 sam p les. The detections ranged from 0.013 ug/L to 0.56 ug/L.

14b. Ground Water

The Tier I screening m odel, SCI-GROW
, was used to estim ate drinking water concentrations derived from groundwater. Acut e 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 m odeling assum e s applications are m a de at the m a xim um rate for each crop on the current label, using the labeled m e thods of app lication (i.e., T-banded, in-furrow, or knifed-in). The half-life inputs in the m odel are derived from direct m easurem ents of terbufos parent and its degradates from an aerobic soil m e tabolism study (MRID 00156853).

Monitoring of groundwater supplies for terbufos has been lim ited. Inform ation on terbufos in groundwater has been gathered by the registrant, USGS NAW QA, EPA’s Pesticides in Groundwater Database, and som e states within the m a jor use areas. These data represent 4,563 sam p les from 13 states, including 20 detections of parent terbufos with an additional 7 apparent detections in Iowa that are questi onable or unconfirm e d. Thirteen wells were also

sam p led in Iowa for terbufos sulfone, but no re sidues 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 determ ined that the groundwater m onitoring data available to the Agency are inadequate for use in assessing groundwater exposures for several reasons, including that the m onitoring studies did not analyze for the degradates of concern.

c. Drinking Water Levels of Comparison (DWLOCs)

To determ ine the m a xim um allowable contribution of water-containing pesticide residues
perm itted in the diet, EPA first looks at how m u ch of the overall allowable risk is contributed by food (and if appropriate, residential uses) then determ ines a “drinking water level of

com p arison”(DW L OC) to determ ine whether m odeled or m onitoring levels exceed this level. The Agency uses the DW LOC as a surrogate to capture risk associated with exposure from pesticides in drinking water. The DW LOC is the m a xim um 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 sum m a rized here. Details of this analysis, which used screening m odels, are found in the HED Hum a n Health Risk Assessm ent dated Septem ber 2, 1999 and the EFED Environm ental Risk Assessm ent dated August 26, 1999.

For acute risk, groundwater and surface water EECs exceed the acute DW LOCs for infants and children (Table 3). Even if it is assum e d that there are no food exposures to terbufos, drinking water alone, based on m odel estim ates, would result in exceedences of the risk cup, particularly f o r inf a nts and children. The table below presents the calculations f o r the acute drinking water assessm ent.

Table 3. Summary of DWLOC Calculations for Acute Risk

15Population Subgroup Acute PAD ( m g/kg/day ) Food Exposure ( m g/kg/day ) Allowable Wa t e r Exposure ( m g/kg/day ) Maximum Groundwater EECs (S CIGROW, total toxic residue, ppb) Maximum S u rface W a ter EECs (PRZM/ EXAMS, total toxic residue, ppb) Maximum S u rface W a ter 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 y r) 3.0e-4 2.6e-4 4.1e-5 7.4 13.3 25.5 0 .41

All Infants

(<1 y r) 3.0e-4 2.5e-4 5.0e-5 7.4 13.3 25.5 0 .50

Children (1-6 y ears) 3.0e-4 1.4e-4 1.6e-4 7.4 13.3 25.5 1 .60

Children

(7-12
y ears ) 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 DW LOC’s for all population subgroups, regardless of the treated crop (Table 4). Even if it is assum e d that there are no food exposures to terbufos, drinking water alone, based on m odel estim ates, would result in exceedences of the risk cup, particularly for infants and children. The table below presents the calculations for the chronic drinking water assessm ent.

16Table 4. Summary of DWLOC Calculations for Chronic Risk

Population Subgroup Chronic PAD ( m g/kg/day ) Food Exposure ( m g/kg/day ) Allowable Wa t e r Exposure ( m g/kg/day ) Maximum GroundwaterEECs ( SCIGROW, total toxic residue, ppb) Maximum S u rface W a ter EECs (PRZM/ EXAMS, total toxic residue, ppb) Maximum S u rface W a ter 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 y r) 5.0e-5 5.0e-6 4.5e-5 7.4 5 .5 5.9 0 .45

All Infants

(<1 y r) 5.0e-5 4.0e-6 4.6e-5 7.4 5 .5 5.9 0 .46

Children (1-6 y ears) 5.0e-5 2.0e-6 4.8e-5 7.4 5 .5 5.9 0 .48

Children

(7-12
y ears ) 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 m o st subpopulations. However, there are uncertainties which lead the Agency to expect that exposure from drinking water m a y not be as high as the levels used in the developm ent of the risk assessm ent. These uncertainties are described in Section IV.

3. Aggregate Risk

An aggregate risk assessm ent looks at the com b ined risk from dietary exposure (food and drinking water routes). Acute and chronic a ggregate risk assessm ents were conducted for terbufos. Since terbufos is not registered for use in residential settings, residential exposures are not expected, and aggregate short- and interm ediate-term exposures were not estim ated. Results of the aggregate risk assessm ent are sum m a rized here, and are discussed in the terbufos hum an health risk assessm ent.

The Agency was only able to quantify food sources of dietary exposure to terbufos because dietary exposures through drinking water have only been estim ated using m odels. Neither adequate groundwater or surface water m onitoring data were available to estim ate potential drinking water exposures to terbufos and its degradates.

Acute Aggregate Risk Assessm ent : Potential acute dietary risks from food sources alone do not exceed the Agency’s level of concern. The m o st exposed subpopulation, non-nursing infants, consum e 86% of the acute PAD at the 99.9th percentile of exposure, based on highly refined exposure estim ates. However, when dr inking water exposure concentrations, derived

17from groundwater and surface water m odels, are added to the acute dietary risk assessm ent, the potential exists for acute dietary exposures through drinking water that exceed the acute DW LOCs, resulting in acute aggregate risks of concern.

Chronic Aggregate Risk Assessm ent : In the case of the food com ponent of the chronic aggregate risk assessm ent, risks are well below the Agency’s level of concern. No m o re than 9% of chronic PAD is consum ed for infants. However, based on m odeled estim ates of terbufos concentrations in groundwater and surface water, the potential exists for chronic dietary exposures through drinking water that exceed the chronic DW LOCs, resulting in chronic aggregate risks of concern.

4. Occupational and Residential Risk

Occupational workers can be exposed to a pesticide through m i xing, loading, and/or applying a pesticide, or re-entering treated sites. Terbufos is not registered for use in residential settings so hom eowner or non-occupational exposur es are not expected. Occupational handlers of terbufos include individual farm ers or gr owers who load and/or apply pesticides, and professional or custom agricultural applicators. Risk for all of the potentially exposed populations is m easured by a Margin of Exposure (MOE) which determ ines how close the occupational exposure com e s 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 m o st current toxicity inform ation available for terbufos including a 28 day derm al toxicity study. The toxicological endpoints, and other factors used in the occupational risk assessm ent for terbufos are listed below in Table 5a. The endpoints selected for the derm al and inhalation risk assessm ents have been applied to both short-term and interm ediate-term exposure scenarios.

18Table 5a. Summary of Toxicological Endpoints and Other Factors Used in the Human Occupational Risk Assessments for terbufos

Assessm ent D ose E ndpoi nt St udy Absorpt i o n factor

Sh o r t-term an d In term ed iateTerm derm al Count er 15G: NOAEL = 0.32 m g / kg/ day

Count er CR: NOAEL = 2.0 m g / kg/ day plasm a and brai n C h E in h i b itio n

plasm a and RBC Ch E in h i b itio n 28-day derm al t oxi ci t y st udy i n rat s usi ng C ount er 15G (M R I D 44520501)

28-day derm al t oxi ci t y st udy i n rat s usi ng C ount er C R (M R I D 44690501) NA 1

Sh o r t-term an d In term ed iateterm in h a latio n NOAEL = 0.0035

m g / kg/ day 2 R e d bl ood cel l
, plasm a , and brai n C h E in h i b itio n 90-day subchroni c i nhal a t i o n st

udy i n rat s (M R I D 00258710) 100%

1 A derm al absorpt i on fact or i s not requi red for t e rbufos si nce product

- speci fi c dat a were avai l a bl e from t w o derm al
t oxi ci t y st udi es.
2 C a l c ul at ed as fol l o ws: 0.00001 m g / L x 100% absorpt i on x 43.5 L/ hr/ kg for rat st rai n x 8 hour durat i on x 1 act i v i t y fact or = 0.0035 m g / kg/ day

. In acute toxicity studies, terbufos exhibits severe acute toxicity via the oral, derm al, and inhalation routes of exposure (Table 5b). Terbufos is also considered to be a severe eye and derm al irritant, although derm al and eye irritant a ssessm ents were not possible due to death of all test anim als within 24 hours of exposure in the eye and derm al irritation studies. The derm al sensitization study was waived due to lethality.

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

R out e of Exposure Toxi ci t y C a t e gory C a t e gory B a si s S t udy Ty pe and R e sul t s M R ID No.

Oral I LD 50 # 50 m g / k g Acut e oral t oxi ci t y st udy i n rat s, LD 50 . 1.5 m g / k g 00029863

Derm al I LD 50 # 200 m g / k g Acut e derm al t oxi ci t y st udy i n rabbi t s, LD 50 = 0.87 m g / L m a l e s and fem a l e s 00258710

In h a latio n I LC 50 # 0.05 m g / L Acut e i nhal a t i on st udy i n rat s, LC 50 = 1.7 F g/ L 41538101

Eye Irritatio n I Co rro siv e Prim ary eye irritatio n stu d y in rab b its, al l ani m al s di ed wi t h i n 24 hrs of exposure 00044957

Derm al Irritatio n I C o rro siv e Prim ary sk in irritatio n stu d y in rab b its, al l ani m al s di ed wi t h i n 24 hrs of exposure 00044957

Derm al Sen s itizer NA NA W a iv ed d u e to leth ality NA

b. Exposure

19Two chem ical- and scenario-specific occupational exposure studies were subm itted 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 tim e (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 tim e (open cab applications) (MRID 44793301, Exhibit 2).

In addition, a m e thod validation study (MRID 44793301) was subm itted to establish the
param e ters for the analytical m e thods used in the occupational exposure studies. These studies were reviewed and accepted by the Agency, and are being used in the terbufos occupational risk

assessm ent. 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 m a ny of the exposure scenarios for which it was m onitored in the studies. A large percentage of the exposure values were either below the lim it of detection (LOD) or lim it 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 assessm ent dated August 26, 1999, for additional inform ation on results from these two studies.

W h en conducting occupational risk assessm ents, EPA usually com b ines chem icalspecific data with PHED data to obtain a m o re robust data set. The terbufos worker exposure studies, however, have not been integrated with PHED because the Agency believes physical differences in the form ulations and packaging preclude com b ining 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 attem p t to sim u late open cab conditions. In PHED, applicators in an enclosed cab only wear baseline PPE, however, in this study, applicators wore

m a xim um personal protective equipm ent.

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 estim ated exposures a pesticide handler would receive when m a king 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 m i nim um , m a xim um , and geom etric m ean values. These values have been verified by the Agency, and are being used in the risk assessm ent to represent typical to m a xim um exposures. The geom etric m ean values (a m easure of the central tendency of the data) are the closest

20approxim a tion of the unit exposure values, and are the values used to determ ine whether the exposures exceed the Agency’s level of concern.

Anticipated use patterns, application m e thods, and range of application rates were derived from the current terbufos labeling. App lication 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 chem ical- and scenario-specific occupational exposure studies are available for terbufos, the com b inations of engineering controls and personal protective equipm ent (PPE) evaluated in the risk assessm ent are slightly different than com b inations typically considered by the Agency. First, all Counter 15G is loaded using a Lock-N-Load, closed handling system
, whereas Counter CR form ulation is available in both Lock-N-Load packaging and open bags. Secondly, current terbufos labels require appli cators and other handlers to wear coveralls over long-sleeved shirt and pants, waterproof glove s, chem ical-resistant footwear plus socks, protective eye-wear, chem ical-resistent headgear, a chem ical-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]

• M inim um PPE: B aseline + chem ical resistant gloves and a dust/m ist respirator with a protection factor of 5. [Note: This scenario was used only for exposure data developed using the Pesticide Handlers Exposure Database]

• Maxim um PPE: Baseline + coveralls, chem ical 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 chem ical- and scenario specific exposure m onitoring studies]

• Engineering controls: E ngineering 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]

• E ngineering controls + PPE: E ngineering controls such as an enclosed cab tractor or closed loading system for granulars with associated PPE required by the W PS when engineering controls are used (e.g., apron and chem ical resistant gloves). [Note: This scenario was used only for exposure data developed from

21the Counter 15 G chem ical- and scenario specific exposure

m onitoring studies]

A chem ical 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 com p leted occupational risk assessm ents for short- and interm ediate-term duration, to reflect potential exposures from 1-30 days up to several m onths. Som e applicators m a y apply terbufos over a period of weeks because they m a y need to cover large acreage, or they m a y be professional applicators com p leting num erous applications within a region. A chronic risk assessm ent was not conducted for terbufos because exposures of a chronic duration are not expected.

c. Occupational Handler Risk Summary

In the revised risk assessm ent, risks to handlers has been assessed using separate toxicological endpoints for both derm al and i nhalation exposures because the dose levels at which effects occur differ depending on whether te rbufos was deposited on the skin or inhaled. In addition, the Agency selected two sets of derm al endpoints to assess derm al exposures because the physical nature of each form ulated product has different im pacts on derm al toxicity. A single endpoint has been selected to assess i nhalation exposures for both granular form ulations 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 derm al and inhalation exposures. These endpoints are believed to be appropriate for both short- and interm ediate-term risk

assessm ent. All the risk calculations f o r handlers com p leted in this assessm ent are included in Appendix A of the Occupational and Residential Exposure (ORE) Chapter dated August 26, 1999.

Analyses were conducted to determ ine the MOEs at typical and m a xim um application rates, and at typical and m a xim um 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 docum ent, sum m a rize the exposure scenarios at m a xim um application rates and acreage-treated.

1) Agricultural Handler Risk

For terbufos, com b inations of target crops, application rates, acreage treated, and worker scenarios were assessed for short- and interm ediate-term exposures for each of the end-use products. The Agency has som e rem a ining risk concerns for exposure scenarios assessed for the Counter 15G and Counter 20CR form ulations when used in a m a nner consistent with the
param e ters 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

22assessing open cab exposures for Counter 15G given the study’s reliance on unrefined protection factors and since em pirical 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 (m axim um PPE), the Agency has risk concerns for loading and applying Counter 15G (Table 6). However, based on the chem ical specific study, the Agency has risk concerns only for loading Counter 15G (T able 6). This study determ ined 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 som e exposure scenarios (Table 7). There are no risk concerns when the Counter 20CR form ulation is used in closed system s (Lock-N-Load) and open or closed cabs.

All the MOEs in the tables below are based on com b ined derm al and inhalation MOEs. The scenario num bers correspond to the scenario num bers 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 rem a ining risk concerns fo r Counter 15G are based on the chem ical specific study for loading and PHED data (m axim um PPE). For Counter 20CR, the rem a ining risk concerns are based on the chem ical specific study. The scenarios with rem a ining risk concerns

are:

(1b) Loading Counter 15G in closed system using the North Carolina SLN 2x rate on corn, the m a xim um rate/acreage on sugar beets, and the m a xim um rate/acreage on sorghum .; (2b) Applying Counter 15G in open cabs (m axim um PPE) using the m a xim um rate/acreage on corn, the North Carolina SLN 2x rate on corn, the

m a xim um rate/acreage on sugar beets, and the m a xim um rate/acreage on sorghum .; (1c) Loading Counter 20CR in open bags using the North Carolina SLN 2x rate on corn, the m a xim um rate and acreage on sugar beets, the m a xim um rate and acreage on sorghum .;

Table 6 describes the short- and interm ediate-term MOEs derived from PHED and chem ical specific data for Counter 15G exposure scenarios. Table 7 describes the short- and interm ediate-term MOEs derived from the Agency’s use of the chem ical 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 derm al 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 m a xim um rate (2.6 lbs a.i./A).

2324Table 6. Counter 15G, Agricultural Uses: Co mpleted using PHED and chemical specific data, combined dermal & inhalation MOEs.

Sh o r t-Term an d In term ed iate-Term MOEs

Scenario Crop Type Rate Acres M axim um PPE (PHED dat a ) Eng. C ont rol s (chem i cal specific data 1 )

(1b) Loadi n g C ount er 15G form ul at i on i n lock-n-load
cont ai ners C o rn 1.3 213 4.3 105.2

2.6 213 2.1 52.6

2.6 150 n.c. 2 75
Sugar B eet s 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) Appl y i ng C ount er 15G C o rn 1.3 213 5.3 314.4

2.6 213 2.7 157.2

Sugar B eet s 1 .96 213 3.5 208.6
Sorghum 1.96 213 3.5 208.6

1 For l o adi ng- C h em i cal -resi st ant apron over l ong pant s, l ong sl eeve shi r t , shoes, socks, chem i cal -resi st ant gl oves. For appl y i ng- Encl osed cabs

2 No t calcu lated

Table 7. Counter CR, Agricultural Uses: Completed using chemical specific data, combined dermal & inhalation MOEs

Sh o r t-Term an d In term ed iate-Term MOEs

Scenario Crop Type Rate Acres M ax. PPE 1 wi t hout respirator Max. PPE 1 with resp irato r 2

(1c) Loading C ount er C R Form ul at i on i n Open Bags C o rn 1.3 213 13.0 128.7

2.6 213 6.5 64.4

Sugar B eet s 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) Appl y i ng C ount er 20 C R C o rn 1.3 213 687.0 5752.0

2.6 213 343.5 2876.0

Sugar B eet s 1 .96 213 455.7 3815.1

25Sh o r t-Term an d In term ed iate-Term MOEs

Scenario Crop Type Rate Acres M ax. PPE 1 wi t hout respirator Max. PPE 1 with resp irato r 2

Sorghum 1.96 213 455.1 3815.1

1 For l o adi ng- Apron over l ong pant s, l ong sl eeve shi r t , shoes, socks, and chem i cal -resi st ant gl oves. For appl y i ng- C overal l s over l ong pant s, l ong sl eeve shi r t , shoes, socks, and chem i cal -resi st ant gl oves.
2 R e spi r at or = PF 10

3 No t calcu lated

2) Post-Application Occupational Risk

EPA does not believe there is a significant potential for post-application exposures to terbufos based on application m e thods, tim ing, and frequency. In addition, the Agency does not believe there is signif i cant potential f o r drif t into adjoining areas such as residential areas since the product is soil incorporated in granular form using ground equipm ent only. Terbufos use in residential areas is not perm itted. Given these f actors, the Agency concludes that the Restricted Entry Intervals (REIs) established under EPA’s W o rker Protection Standards (W PS) are sufficient to protect workers who m a y 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 sum m a ry of the Agency’s environm ental risk assessm ent is presented below. For a detailed discussion on all aspects of the environm ental risk assessm ent, see the Environm ental Fate and Effects Division chapter, dated August 26, 1999, available in the public docket, and supporting docum ents dated August 20 and August 5, responding to com m e nts from the registrant and other stakeholders.

Several revisions have been m a de since the prelim inary risk assessm ent was com p leted, and include:

• m odifications to the ecological risk assessm ent and characterization, including an update of the Agency’s aquatic and terrestrial incident database, based on inform ation supplied by states, the registrant, and other stakeholders.

• c onsideration of new environm ental fate data subm itted on the abiotic hydrolysis and aerobic aquatic m e tabolism of parent terbufos and its degradates.

• r evisions to the estim ated concentrations of terbufos and its degradates in surface water and groundwater using the PRZM-EXAMS and SCI-GROW m odels;

• u se of index reservoir and percent crop area m odifications to the PRZM-EXAMS

m odeling, and the available environm ental fate data for terbufos, to estim ate terbufos and its degradates in surface water used for drinking water.

26EPA has used the quotient m e thod to evaluate potential risks to nontarget organism s from use of terbufos. Applying this m e thod, risk quotients (RQs) have been calculated by com p aring estim ated concentrations of terbufos in the environm ent (or EECs) to results from ecological toxicity studies in a variety of organism s. 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 ch aracterized the ecological risk to nontarget organism s 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 environm ental fate database for terbufos is m o stly com p lete, and provides a

com p rehensive understanding of terbufos fate and transport in the environm ent.

a. Degradation and Mobility

Based on a review of the environm ental fate database for terbufos, total toxic residues of terbufos (parent + degradates) are considered to be highly m obile and persistent. Hydrolysis and

m i crobial degradation are the prim ary dissipation processes for terbufos in the environm ent when it is incorporated into the soil as required by the current label. The linear m e tabolic half

life of parent terbufos in aerobic soil is approxim a tely 27 days (5.6 days for non-linear). Under abiotic (i.e., not biological) conditions, the hydrolys is half-life for parent terbufos is 12.3 to 13.7 days in the typical range of environm ental pH values (pHs 5,7, and 9). Volatilization m a y be a

m a jor dissipation route for the portion of parent terbufos that rem a ins on the soil surface after incorporation. The relatively high vapor pressure (3.16 x 10 -4 m m Hg) and the observed Henry’s Law Constant (6.58 x 10 -3 ) suggest that som e parent m a terial will dissipate by diffusion into the
atm o sphere, but that the expected am ount varies depending on site conditions and application

m e thods.

The m e tabolites of toxicological concern, terbuf os sulf oxide and terbuf os sulf one, are

m o re m obile and substantially m o re persistent than parent terbufos. Terbufos sulfoxide and sulfone have non-linear half-lives in aerobic soil of 116 and 96 days, respectively. These

m e tabolites are also m obile in all tested soils with Freundlich K ads values ranging from 0.40 to 2.93, and m a y reach groundwater when terbufos is used in locations where irrigation or rain
water m oves through the soil profile to groundwater. In addition, terbufos parent and its

m e tabolites m a y 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 m a jor degradates, terbufos sulfoxide and su lfone, to runoff to surface water sources, and the potential for the degradates to leach to groundwater sources. The PRZM-EXAMS m odel was used to estim ate surface water concentrations, and SCI-GROW was used to estim ate groundwater concentrations. Although som e m onitoring data for terbufos were available, these data were deem ed of lim ited value for several reasons, including that the degradates of concern were typically not included as part of the analyses.

27The data inputs used in the PRZM-EXAMS m odel were based on results from an aerobic aquatic m e tabolism study in pond water for parent terbufos and the terbufos sulfoxide and sulfone degradates (MRID 44862502). EPA used these data to determ ine the expected persistence of parent terbufos and terbufos sulf oxide and sulfone in water, and the form ation rate of terbufos sulfone from applied sulfoxide. Ter bufos 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 estim ating concentrations of terbufos in surface water since the aerobic m e tabolism data were deem ed to be m o re relevant. However, for groundwater, the hydrolysis data provided useful inform ation on the persistence and degradation products in the event terbufos were to reach groundwater sources.

b. Field Dissipation

The database f o r f i eld dissipation is com p lete. The terrestrial f i eld data subm itted indicate that terbufos dissipated in the field with half-lives of 24 days in sandy loam in California, and 14-40 days in loam y and sandy loam soils in Illinois and Colorado. These halflives are com p arable to findings from the aerobic soil m e tabolismstudy discussed above (halflife 27 days). Data from the open scientific literature (Felsot, et al., 1987) reported half-lives of 11-16 days f o r parent terbuf os 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 evaluati on from laboratory and field studies and adverse incidents in the field, som e of which were associated with m i suse/m isapplication. Granular pesticides, such as the terbufos form ulations, present a unique hazard to wildlife in that the granules m a y be ingested directly by birds foraging for seed and grit at or below the soil surface. Birds and m a m m a ls m a y also ingest granules adhered to the surface of invertebrate prey, such as earthworm s and grubs, or through ingestion of wate r or food sources contam inated 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

m a m m a lian species from 2.2 to 327. The ranges provided reflect differences in the application

m e thod and rate, and size of the bird or m a m m a l. Both acute avian and m a m m a lian risks exceed the Agency’s LOC of 0.5, indicating potential risks of concern to terrestrial organism s. Acute RQs associated with banded applications tend to be greater than RQs calculated for other application m e thods (e.g., in-furrow) due to less efficient soil incorporation. The database to assess risk to birds and m a m m a ls is com p lete.

283. Risk to Aquatic Species

The Agency is concerned about potential adverse effects to nontarget aquatic species, based on the Agency’s aquatic LOC assessm ent, which is strongly supported by fish kill incidents associated with the use of terbufos on co rn. No aquatic field studies are available. The basis for the Agency’s aquatic risk concern is sum m a rized below. The database to assess risk to aquatic species is com p lete.

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 app lications 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 m a y be due to the persistence of the degradates. As indicated above, the surface water EECs calculated by the Agency are based

on m easurem ents obtained from an aerobic aquatic m e tabolism study on terbufos parent and the terbufos sulfoxide and sulfone degradates.

Note that for application m e thods other than banded, the Agency’s estim ated exposures equal zero. However, fish kills associated with other m e thods 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 m odel used by EPA to estim ate concentrations of terbufos and its degradates in surface water m a y not adequately represent the availability of the pesticide for runoff under all conditions.

b. Aquatic Incidents

Terbuf os is the leading cause of f

i sh kill incidents reported to EPA f o r any pesticide applied to corn, and ranks f ourth in f i sh kill incidents reported to EPA f o r any pesticide applied to any crop. From 1976 to present, 96 fish kill incidents involving terbufos have been reported to the Agency, m o stly by the registrant under FIFRA 6(a)(2), adverse effects reporting requirem e nts. A causal relationship between terbuf os and f i sh kills has not been f u lly established in all of the incidents.

The average rate of incidents is about 4 per year, although in any given year the num ber of incidents reported can fluctuate broadly. For exam ple, 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

29accounting of all the incidents. The following sum m a rizes som e other key points concerning the incidents. Refer to the environm ental assessm ent and addenda for additional details.

• A ll the incidents reported to the Agency are associated with the corn use, involve all m e thods of application, and both gr anular form ulations (Counter 15G and Counter CR).

• A bout 85 percent of the incidents to date have occurred in the m i dwest, corn belt region (Iowa, Indiana, Illinois, Nebraska, Ohio). Som e incidents have occurred in North Carolina.

• M ost of the incidents occurred in static water bodies (“farm ponds”) ranging in size from 2 to 20 acres; som e occurred in canals feeding into rivers.

• I ncidents generally occurred from 2 days to 3 weeks after application.

• I ncidents were reported on property not owned by the applicator/farm e r, in recent cases, and involve reports of substantial econom ic loss, im pacts to quality of life, pet m o rtality, and concerns about health of people swim m i ng in im pacted lakes and ponds.

• I ndividual incidents indicate a broad range of m o rtality; from 30 up to 90,000 fish

m o rtalities. On average 3,600 m o rtalities were reported per incident based on data from 1976 to 1998. Nineteen incidents reported greater than 1,000

m o rtalities.

• 51% of the incidents were defined as highly probable or probable where terbufos and/or its degradates were identified from water analysis of im pacted surface water bodies or there was adequate inform ation on the application of the chem ical. 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 m a ny 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 m i sapplication.

• I n a lim ited num ber of cases, in the early 1990' s, it appears that pasture/grass buffer strips or setbacks did not prevent incidents.

• M ost of the incidents appear to be associated with norm a l use.

• I n som e of the incidents, rainfall was reported as occurring over a period of days to weeks prior to the incident. Based on the lim ited weather inf o rm ation provided, the Agency believes the incidents could be associated with norm a l spring rain events, as opposed to unusually severe rainfall events over a short period of tim e.

304. Endangered Species

The Agency has initiated three consultations with the Fish and W ildlif e Service (FW S ) on the potential effects of terbufos corn use on endangered and threatened species. To date, the FW S has issued two Biological Opinions. In these Opinions, the FW S 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 FW S 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 m e thods, less refined risk assessm ent procedures, and an older approach to consultation which is currently being revised through interagency collaboration.

EPA’s current assessm ent of ecological risks uses both m o re refined m e thods 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) m a y need to be reassessed and m odified based on these new approaches.

The Agency is currently engaged in a Proactive Conservation Review with FW S 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

assessm ents and consultations. Subsequent to the com p letion of this process, the Agency will reassess the potential effects of terbufos use to federally listed threatened and endangered species. At that tim e, the Agency will also consider any regulatory changes recom m e nded in the RED that are being im plem ented. Until such tim e as this analysis is com p leted, the overall environm ental effects m itigation strategy articulated in this docum ent and any County Specific Pam phlets described below which address terbuf os, will serve as interim protection m easures to reduce the likelihood that endangered and threatened species m a y 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 Ag ency to determ ine, after subm issions 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 subm ission of the generic (i.e., an active ingredient specific) data required to support reregistration of products containing terbufos active ingredients.

The Agency has com p leted its assessm ent 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 assessm ent that has not considered the cum u lative effects of organophosphates as a class. Based on a review of these data and public com m e nts on the Agency’s assessm ents for the active ingredient terbufos, EPA has sufficient inform ation on the hum an health and ecological effects of terbufos to m a ke an interim decisions as part of the

31tolerance reassessm ent process under FFDCA and reregistration under FIFRA, as am ended by FQPA. The Agency has determ ined that terbufos products are eligible for reregistration provided that: (i) current data gaps and additional data needs are addressed; (ii) the risk

m itigation m easures outlined in this docum ent are adopted, and label am endm ents are m a de to reflect these m easures; and (iii) cum u lative risks considered for the organophosphates support a final reregistration eligibility decision. Label changes are described in Section IV. Appendix B identif ies the generic data requirem e nts that th e Agency reviewed as part of its interim determ ination of reregistration eligibility of terbuf os, and lists the subm itted studies that the Agency found acceptable.

Although the Agency has not yet considered cum u lative risks for the organophosphates, the Agency is issuing this interim assessm ent now in order to identif y risk reduction m e asures that are necessary to support the continued use of terbufos. Based on its current evaluation of terbufos alone, the Agency has determ ined that terbufos products, unless labeled and used as specified in this docum ent, would present risks inconsistent with FIFRA. Accordingly, should a registrant f a il to im plem ent any of the risk m itigation m easures identif ied in this docum ent, the Agency m a y take regulatory action to address the risk concerns from use of terbufos.

At the tim e that a cum u lative assessm ent is conducted, the Agency will address any outstanding risk concerns. For terbuf os, if all changes outlined in this docum ent are incorporated into the labels, then all current risks will be adequately m a naged. But, because this is an interim RED, the Agency m a y take f u rther actions, if warranted, to f i nalize the reregistration eligibility decision for terbufos after assessing the cum u lative risk of the organophosphate class. Such an increm ental approach to the reregistration process is consistent with the Agency’s goal of im proving the transparency of the reregistration and tolerance reassessm ent processes. By evaluating each organophosphate in turn and identifying appropriate risk m itigation m easures, the Agency is addressing the risks from the organophosphates in as tim ely a m a nner as possible.

Because the Agency has not yet considered cum u lative risks for the organophosphates, this reregistration eligibility decision does not f u lly satisf y the reassessm ent of the existing terbufos food residue tolerances as called for by the Food Quality Protection Act (FQPA). W h en the Agency has considered cum u lative risks, terbuf os tolerances will be reassessed in that light. At that tim e, the Agency will reassess terbufos along with the other organophosphate pesticides
to com p lete the FQPA requirem e nts and m a ke a final reregistration determ ination. By publishing this interim decision on reregistration eligibility and requesting m itigation now f or the individual chem ical terbufos, the Agency is not deferring or postponing FQPA requirem e nts; rather, EPA is taking steps to assure that uses which exceed FIFRA’s unreasonable risk standard do not rem a in on the label indefinitely, pending com p letion of assessm ent required under the FQPA. This decision does not preclude the Agen cy from m a king further FQPA determ inations and tolerance-related rulem a kings that m a y be required on this pesticide or any other in the fut u re.

If the Agency determ ines, before finalization of the RED, that any of the determ inations described in this interim RED are no longer appropriate, the Agency will pursue appropriate action, including but not lim ited to, reconsider ation of any portion of this interim RED.

32B. Summary of Phase 5 Comments and Responses

W h en m a king its interim reregistration decision, the Agency took into account all

com m e nts received during Phase 5 of the OP Pilot Process. These com m e nts in their entirety are available in the docket. The Agency received com m e nts and a risk m itigation proposal from the registrant, BASF Corporation. The International Banana Association also sent com m e nts on the risk assessm ent and USDA com m e nted on ecological risks of terbufos. The Agency also received 113 com m e nts from various agri-business com p anies and associations, com m odity

com p anies, farm bureaus, universities, extension, and state agencies, as well as private citizens, supporting the use of terbufos. Com m e nts opposing the use of terbufos were received from the Defenders of W ildlife and a private citizen. The Agency also received six com m e nts on fish kill incidents attributed to terbufos.

BASF Corporation subm itted various com m e nts pertaining to the Occupational and Residential Revised Risk Assessm ent. Som e of the com m e nts are included below and a

com p lete response to the com m e nts 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 assessm ent.

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 com m e nt. The Agency did use chem ical specific data from studies com p leted by Am erican Cyanam id where appropriate and used PHED data in cases where there was a lack of chem ical-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 derm al exposure in the closed cab with open windows scenario is two orders of m a gnitude less than PHED exposures with open cabs. Therefore, the Agency feels closed cab tractors with open windows is m o re analogous to closed cabs than open cab tractors. This data was used to assess worker risk for enclosed cab scenarios.

Comment

33BASF states that the EPA used 180 acres per day for corn in the chlorethoxyfos

assessm ent, a chem ical with the sam e use pattern as terbufos. In addition, 180 acres is an appropriate m a xim um estim ate given that it is likely that the exposure is shared by two people an average of 20% of the tim e.

Response The Agency has used the acreage estim ates 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 m o re inform ed risk m a nagem e nt decision.

The International Banana Association (IBA) also sent a com m e nt pertaining to the Agency’s use assum p tions for terbufos in bananas. Som e of the com m e nts are included below and a com p lete response to the com m e nts 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 reassessm ent process, EPA assessed the risks associated with this organophosphate. The assessm ent is for this individual organophosphate, and does not
attem p t to fully reassess these tolerances as required under FQPA. FQPA requires the Agency to evaluate food tolerances on the basis of cum u lative risk from substances sharing a com m on

m echanism of toxicity, such as the toxicity expressed by the organophosphates through a

com m on biochem i cal interaction with the cholinesterase enzym e

. The Agency will evaluate the

cum u lative risk posed by the entire class of organophosphates once the m e thodology is developed and the policy concerning cum u lative assessm ents is resolved.

EPA has determ ined that risk from exposure to terbufos is within its own “risk cup.” In other words, if terbufos did not share a com m on m echanism of toxicity with other chem icals, EPA would be able to conclude today that the tolerances for terbufos m eet the FQPA safety standards. In reaching this determ ination EPA has considered the available inform ation on the special sensitivity of infants and children, as well as the chronic and acute food exposure. An aggregate assessm ent was conducted for exposures through food, residential uses, and drinking

34water. Results of this aggregate assessm ent indicate that the hum an health risks from these

com b ined exposures are considered to be within acceptable levels; that is, com b ined risks from all exposures to terbufos “fit” within the indi vidual risk cup. Therefore, with the exception of corn, pop fodder, the terbufos tolerances rem a in in effect and unchanged until a full reassessm ent of the cum u lative 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 assessm ent, tolerances f o r residues of terbuf os in/on plant com m odities [40 CFR §180.352] are presently expressed in term s of the com b ined residues of terbufos [( S

­ ((1, 1-dim e thyl)thio)m e thyl) O
, O -diethyl phosphorodithioate] and its cholinesterase-inhibiting

m e tabolites [40 CFR §180.352(a)]. The Agency concludes that the tolerance expression should be stated in term s of " ...terbufos...and its phosphorylated (cholinesterase-inhibiting) m e tabolites:

• phosphorothioic acid, S -( t -butylthio)m ethyl O
,. O -diethyl ester;

• phosphorothioic acid, S -( t -butylsulfinyl)m et hy l O
,. O -diethyl ester;

• phosphorothioic acid, S -( t -butylsulfonyl)m ethyl O
, . O -diethyl ester;

• phosphorodithioic aci d, S -( t -butylsulfinyl)m ethy l O
,. O -diethyl ester;

• phosphorodithioic acid, S -( t -butylsulfonyl)m ethyl O
, . O -diethyl ester;

The chem ical nam e for terbufos specified in 40 CFR §180.352(a) is incorrect, and should be revised to read as "phosphorodithioic acid, S -( t -butylthio)m ethyl 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 m e tabolites. Please note that several of the com m odity def i nitions 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+CW H R); corn, sweet, forage; corn, sweet, fodder; sorghum , fodder, sorghum , forage, and sorghum , grain. Certain com m odity definitions of the above tolerances are not in accordance with the current definitions and therefore need to be updated.

An adequate m e thod is available for data collection and enforcem ent of terbufos tolerances in or on plant com m odities. The GLC/flam e ionization-detection m e thod for determ ining terbufos and its phosphorylated m e tabolites is described in PAM, Vol. II, as Method I. The hazardous reagent benzene is specified in this m e thod.

Method M-1754, a m odification of Method I in PAM that substitutes acetone for benzene and m e thylene chloride for chloroform , underwent a successful Residue Analytical Laboratory

m e thod validation trial and was forwarded to FDA for revision of PAM, Vol II.

35Table 8a. Tolerance Summary for Terbufos.

Co m m o d ity Current Tolerance,

ppm Tolerance
Reassessm ent*, ppm C o mme n t / [Co rrect Co mmo d ity Defin itio n ]

T o l erances L i sted Under 40 CFR §352

Bananas 0.025 0.025 B a nana

B eets, sugar, roots 0.05(N) 0.05 The negl i g i b l e resi due resi due (N) shoul d be del e t e d. beet , sugar, root s
Beets, sugar tops 0.1 0 .1 beet , sugar, t ops
Corn, field, fodder 0.5 0 .5 corn, fi el d, st over
Corn, field, forage 0.5 0 .5 NA
Corn, pop, fodder 0.5 0 .5 corn, pop, st over
Corn, pop forage 0.5 r evoke NA

Corn, grai n 0.05(N) 0.05 The tolerance for “Corn, grain” should be replaced with separate tolerances for co rn , field , g ra i n and C o rn, pop, grai n

. The negl i g i b l e resi due resi due (N) shoul d be del e t e d

Corn, sweet (K=CWHR) 0.05(N) 0.05 corn, sweet , kernel pl us cob wi t h husks rem oved The negl i g i b l e resi due resi due (N) shoul d be del e t e d

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 , grai n, st over
Sorghum, forage 0.5 0 .5 sorghum , grai n, forage
Sorghum, grain 0.05 0.05 sorghum , grai n, grai n

* The term “reassessed” here is not m e ant to im ply that the tolerance has been reassesse d as required by FQPA, since this toler ance m a y be reassessed only upon com p letion of the cum u lative risk assessm ent of

all organophosphat e s, as required by t h is law

. Rat h er, it provides a tolerance level for this single chem ical, if no cum u lative assessm ent w a s required, that is supported by all of the subm itted

residue data.

Codex Maxim um Residue Lim its (MRLs) for the sum of terbufos, its oxygen analog and their sulfoxides and sulfones, expressed as terbufos, have been established for a num ber of plant and anim al com m odities. The Codex def i nition is com p atible with the recom m e nded revision to the U.S. Tolerance definition, which specifically nam e s terbufos, its oxygen analog, and their sulfoxides and sulfones.

36No questions of com p atibility exist with respect to com m odities 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 com m odities as m a ize (corn), popcorn, and sweet corn cannot currently be harm onized with CODEX tolerances; although both U.S. and Codex tolerances in these com m odities are based on the lim it 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.

C o m m odi t y M R L (St e p) (m g/ kg) R eassessed U.S. Tol e rance (ppm ) Co d e x d e fin itio n R eassessed U.S. defi ni t i on

Fodder beet l eaves or
t ops beet , sugar, t ops 1 (5/ 8 ) 0 .1

Maiz e corn, fi el d, grai n 0 .01 (5/ 8 ) 0 .05

Maiz e forage corn, field, forage 1 (5/8) 0 .5

Popcorn corn, pop, grai n 0 .01 (5/ 8 ) 0 .05

Straw and fodder (dry) of cereal grains corn, fi el d, st over corn, pop, st over corn, sweet, stover sorghum , grai n, st over 1 (5) 0 .5 0.5
0.5

1

Sugar beet beet, sugar, roots 0 .1 (5) 0 .05

Sweet corn (corn-on

the-cob) corn, sweet, kernel plus cob wi t h husks rem oved 0.01 (5) 0 .05

2. Endocrine Disruptor Effects

EPA is required under the FFDCA, as am ended by FQPA, to develop a screening program to determ ine whether certain substances (including all pesticide active and other ingredients) "m ay have an effect in hum ans that is sim ilar to an effect produced by a naturally occurring estrogen, or other such endocrine effects as the Adm i nistrator m a y designate." Following the

recom m e ndations of its Endocrine Disruptor Screening and Testing Advisory Com m ittee (EDSTAC), EPA determ ined that there was scientific bases for including, as part of the program
, the androgen and thyroid horm one system s, in addition to the estrogen horm one system

. EPA also adopted EDSTAC’s recom m e ndation that th e Program include evaluations of potential effects in wildlife. For pesticide chem icals, EP A will use FIFRA and, to the extent that effects in wildlife m a y help determ ine whether a substance m a y have an effect in hum ans, FFDCA authority to require the wildlife evaluations. As the science develops and resources allow, screening of additional horm one system s m a y be added to the Endocrine Disruptor Screening Program (EDSP).

37W h en the appropriate screening and/or testing protocols being considered under the Agency’s EDSP have been developed, terbufos m a y be subjected to additional screening and/or testing to better characterize effects related to endocrine disruption.

3. Labels

A num ber of label am endm ents, in addition to the existing label requirem e nts, are necessary in order for terbufos products to be eligible for reregistration. The Agency has determ ined that these m easures, in addition to the existing label requirem e nts, will adequately reduce risks to handlers.

Provided the following risk m a nagem e nt m easures 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 cum u lative risks of the organophosphates. The regulatory rationale for each of the risk m a nagem e nt m easures outlined below is discussed im m e diately after this list of required risk m a nagem e nt m easures.

a. Agricultural Use Exposure Reduction Measures

For agricultural use, the f o llowing m easures are required, in addition to the existing labeling requirem e nts to address drinking water, occupational handler and ecological risks of

concern. The registrant has agreed to these m easures.

• A m e nd the North Carolina SLN registration of Counter 20CR to require the use of a closed loading system

.

• R equire that the Counter 15G label be am ended to indicate that applications m u st be

m a de using enclosed cab tractors.

• R educe the application rate on sorghum from 1.96 lbs. a.i. per acre to 1.70 lbs. a.i.
per acre.

• R equire a 500 ft. vegetative buffer between treated area and surface water on neighboring land

• R equire a 500 ft. vegetative buffer between a standpipe drain outlet and surface water on neighboring land.

• R equire a 66 ft. setback between the treated area and entry points to surface water bodies on non-highly erodible soils

• R equire a 300 foot setback between the treated area and entry points to surface water bodies on highly erodible soils.

• R equire 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

• R estrict loading, rinsing, and washing equipm ent within 300 ft. from surface water bodies or within 50 ft. from wells unless conducted on an im pervious surface.

• R em ove the “over the top” application for European corn borer control on corn.

• R equire 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• T o prevent the f l ow of rainf a ll 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. Homeow ner Use Exposure Reduction Measures

There are no residential uses for terbufos.

D. Regulatory Rationale

The following is a sum m a ry of the rationale for m a naging risks associated with the use of terbufos. W h ere labeling revisions are im posed, specific language is set forth in the sum m a ry tables of Section V of this docum ent.

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 m o st 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 consum ption of food alone. No m itigation m easures are necessary at this tim e to address acute dietary risk from food. Dietary risk from food consum ption is estim ated using anticipated residues from field trial data rather than residues from m onitoring data. Anticipated residues are generally considered to be m o re conservative than m onitoring data in term s of residue levels that consum ers are exposed to in their diet. They represent m a xim um allowed
treatm e nt param e ters and do not account for any reduction in pesticide residue levels that m a y occur from the tim e the crop is harvested until it is consum ed. Additionally, the exposures are based largely on residue values from field trial data below the lim it of detection (LOD), between the LOD and lim it of quantitation (LOQ), or at the LOQ f o r which the Agency assum e d residues to be one half of the LOD. It should be noted that the available PDP m onitoring data, while not appropriate f o r the purposes of quantitative risk assessm ent, showed no detections of terbuf os or terbufos sulfone residues in over 100 sam p les of sweet corn. This suggests that the acute dietary

assessm ent 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

m o st exposed subgroups, infants, the percent chronic PAD values are 9% or less. No m itigation

m easures are necessary at this tim e to address chronic dietary risk from food.

3) Drinking Water

39The acute and chronic dietary risks from drinking water exposure are above the Agency’s level of concern for m o st 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 developm ent of the risk assessm ent. Based on these uncertainties and the anticipated im pacts on water resources from im plem enting the risk reduction m easures contained in this docum ent, the Agency believes that the risks from drinking water are not of concern.

The drinking water risk assessm ents are based on screening level m odels that are conservative in their estim ates of drinking water exposure. Actual exposure is expected to be lower than the EEC’s reported in the IRED. An ex am ple of the type of assum p tions used in the

m odel that can contribute to conservative estim ates involves rainfall levels. To determ ine what rainfall level to use in the m odel, the Agency id entifies a peak rainfall level for each of 36 years of

daily rainf a ll data. The m odel then assum e s that rainf a ll will equal the 90th percentile of these 36 annual peak values when estim ating concentrations, a conservative assum p tion. Also, the percent cropped area (PCA) assum p tion for sugar beets and sorghum used in the m odel is 0.87, the default assum p tion. This m eans the m odel assum e s 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 m a jor crop like corn using data subm itted to the Agency is 0.46.

Further, although the available NAW QA m onitoring data were deem ed insufficient for the purpose of quantitative risk assessm ent prim arily due to the f a ilure to include m e tabolites of terbufos, these data yielded surface water concentra tions that were lower than the results of the

m odel. These levels ranged from 0.013 ppb to 0.56 ppb as com p ared to the m odel estim ate for parent terbufos of 9.39 ppm

. To provide additional perspective, it should also be noted that the m a xim um ground water and surface water EEC’s result from m odeling terbufos use on sorghum

. According to sales figures for 2000 provided by the registrant, sor ghum accounts for approxim a tely 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 DW LOC is calculated based on dietary risk from food

consum ption that is estim ated using conservative exposure estim ates (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 m easures contained in this IRED, including the lim itations on sales of terbufos, reducing the m a xim um application rate for sorghum , increasing the depth of incorporation of granules into the soil, rem oval of “over-the-top” applications, and the use of vegetative buffer strips between treated field and water bodies and other areas where water
contam ination 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 im proved protection of water resources fr om terbufos contam ination. This supports the Agency’s belief that drinking water risks will be reduced to a level at which the risk cup is not exceeded.

40Finally, the Agency is requiring surface and ground water m onitoring data to confirm the Agency’s conclusions on dietary risks from drinking water. The Agency notes that drinking
water m onitoring studies are either planned or underway which will inform the Agency regarding its conclusions on levels of terbuf os and its m e tabolites in drinking water. One of these studies is related to the Unregulated Contam inant Monitoring Rule under which the EPA is considering whether or not to set a drinking wate r standard for terbufos under the Safe Drinking W a ter Act. This study is m onitoring the levels of chem icals, including terbufos, in over 300 drinking water plants across the United States. The other study is being sponsored by the Am erican Crop Protection Association which will also m onitor drinking water f o r pesticide residues. In order f o r these studies to be used the Agency will need to conf irm that sam p les were taken from areas of terbufos use and during the tim e period when terbufos is used. Further,

m onitoring for the im portant degradates of terbuf os, 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 m a nner consistent with the engineering control param e ters from the occupational study. This assum e s both use of a closed m i xing and loading system (currently on labels) and enclosed cabs for application (not a current label requirem e nt) . 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 m a xim um labeled rate (1.97 lbs ai/acre) and

m a xim um acreage treated per day assum p tion of 213 acres. In addition, there are risks of concern when applying Counter 15G in open cabs (m axim um PPE) using the m a xim um rate/acreage on corn, the North Carolina SLN 2x rate on corn, the m a xim um rate/acreage on sugar beets, and the m a xim um rate/acreage on sorghum

. The Agency also has risk concerns for the scenario for 15G where application is m a de without a enclosed cab.

For application of Counter 15G, applicator risks are of concern at m a xim um PPE with MOEs ranging from 2.7-5.3. W h en 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 m a xim um acreage treated/day of 213 acres. However, based on survey data from North Carolina, the Agency has determ ined the typical acreage treated per day to be 150 acres. The analysis conducted using this acreage

assum p tion results in a MOE of 75. In addition, the Agency’s benefits assessm ent determ ined there are currently no effective alternatives to terbufos for controlling billbugs in North Carolina fields with high organic m a tter 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 m a xim um rate (1.97 lbs ai/acre) and acreage (213 acres) is also below the target MOE of 100. However, based on a survey the

41Agency determ ined the acreage treated per day to be 130 acres for sugar beets. The analysis conducted using this acreage assum p tion results in an acceptable MOE of 114.

The MOEs for loading Counter 15G on sorghum at the m a xim um rate (1.97 lbs ai/acre) and acreage (213 acres) is below the target MOE of 100. The registrant has agreed to reduce the

m a xim um 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 chem ical’s efficacy against sorghum pests. The prim ary alternative to terbufos, aldicarb, is expensive com p ared to terbufos and the Agency has determ ined that choosing this alternative would reduce the growers net revenues by as m u ch as 78% if used. In addition, other alternatives are not as efficacious in controlling wi reworm s, 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 som e 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 system s (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 perm its terbufos use on corn at twice the labeled m a xim um application rate, is 64. This risk concern can be m itigated if the SLN registration is am ended to require the use of closed loading system s. The North Carolina Departm e nt of Agriculture and Consum er Services, the departm e nt responsible for m a naging state registrations, and the registrant have agreed to

am end the SLN registration to m a ke this a requirem e nt on the label.

The MOEs for loading Counter 20CR in open bags on sugar beets at the m a xim um 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 determ ined the m a xim um 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 m a xim um rate (1.97 lbs ai/acre) and acreage (213 acres) are also below the target MOE of 100. BASF has agreed to reduce the m a xim um rate to 1.7 lbs ai/acre which gives a MOE of 98.

Table 11 describes the necessary PPE and engineering controls to m itigate worker risks.

Table 9. Agricultural Uses: Handler Risk Concerns and Mitigation

Scenario PPE Engineering
C ont rol s

Loadi ng granul ar i n l o ck-n-l oad

cont ai ners (15G and 20 C R form ul at i on) l ong-sl eeved shi r t and l ong pant s, shoes pl us socks chem ical-resistant gloves and chem icalresistant apron lock-n-load

cont ai ner

42Loadi ng granul ar i n open bags (20
C R form ul at i on) coveral l s over l ong-sl eeved shi r t and l ong pant s, chem ical-resistant apron, chem ical resistant gloves, chem ical resistan t foot wear pl us socks, and OV respi r at or none

Appl y i ng 15G granul ar form ul at i o n l ong-sl eeved shi r t and l ong pant s, shoes pl us socks enclosed cab

Appl y i ng 20 C R granul ar form ul at i on covera l l s over l ong-sl eeved shi r t and l ong pant s, chem ical resistant glove s, chem ical resistant foot wear pl us socks none

2) Post-Application Risk

There is a low potential for occupational post-application exposure when pre-em ergent insecticides are used. Terbuf os is applied to the soil directly and is soil incorporated well bef o re the crops are m a ture. The tim ing of the application of terbufos can greatly reduce the potential for post-application exposure. Also, m o st agricultural operations m e chanically plant corn early in the season, which m i nim i zes the potential for derm al contact. Minim a l exposure during harvesting or any other late season activities is expected since terbuf os is prim arily applied preem ergent. Therefore, the Agency does not require a post-application occupational exposure

assessm ent (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, chem ical-resist ant gloves m a de of any waterproof m a terial, chem ical-resistant footwear plus socks, and protective eyewear.

c. Homeow ner Risk Mitigation

Terbufos is not registered for use in residential settings.

2. Environmental Risk Mitigation

The Agency has determ ined that these risks can be reduced to an acceptable level taking into consideration the benefits by a reducing the total am ount of terbufos that can be applied through im posing an annual sales cap and buffers. The registrant has agreed to a phased approach that will ultim ately reduce sales of terbufos by m o re than 55% by 2008 based on 2000 sales figures. By reducing the am ount of terbufos applied in this way the Agency expects that risks to aquatic and terrestrial organism s will be reduced.

The buffers to be im plem ented are; 1) a 500 ft. vegetative buffer between treated area and surface water on neighboring land, 2) a 500 ft. vege tative 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 equipm ent within 300 ft. from surface water bodies or within 50 ft. from wells unless

43conducted on an im pervious surface. All setbacks m u st be planted to a crop or seeded with grass or other suitable cover. Erosion potential of soils can be determ ined by consulting with the National Resource Conservation Service (NRCS).

In addition, the registrant has agreed to rem ove from its labels the “over the top” application on corn f o r 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 inc h. To prevent the flow of rainfall down planted rows, the label text will read “To prevent channe ling 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 m e thods described above will reduce the likelihood that terbufos w ill contam inate surface water. In so doing, nontarget aquatic organism s, especially fish, would be less likely to be exposed to terbufos or its

m e tabolites.

The registrant has also com m itted to voluntarily rem ove use from counties where m u ltiple, verifiable fish kills occur in that county over a period of two or m o re years as the result of the use of terbufos in accordance with the risk m a nagem e nt m easures set forth in this docum ent. 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 prelim inary and the revised hum an health and ecological risk assessm ents identified risks of concern for occupational handlers and terrestrial and aquatic non-target organism s. Since risks of concern in these areas are regulated under FIFRA’s requirem e nt that the Agency consider the risks and benefits of pesticide use in m a king its regulatory decision, the Agency has conducted a benefits assessm ent for use in determ ining the appropriate risk

m a nagem e nt steps to be taken to address these risks. This assessm ent was aim e d at quantifying, to the extent possible, the benefits derived from the use of terbufos on corn prim arily for control of corn rootworm

.

The benefits of terbufos on corn were estim ated using a com p arative product perform a nce

assessm ent (BEAD Mem o -Product Perform a nce Assessm ent Methodology as Applied to Terbufos Use on Field Corn, 12/15/2000). Th is assessm ent relied on data from num erous product perform a nce studies available in the open scientific literature. These data were analyzed using statistical m e thods to determ ine the relative effects on corn yields of using terbufos and other corn insecticides especially tefluthrin. The benefits assessm ent concluded that under m o st conditions the alternative insecticides produced sim ilar 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 perform e d

m o re effectively on som e secondary corn pests. However, there are uncertainties associated with the assessm ent that were taken into consideration when developing the risk m a nagem e nt

m easures.

44The benefits assessm ent was reviewed by several independent external experts and the United States Departm e nt of Agriculture. The re gistrant was also provided a courtesy copy. The university researchers who provided an independent peer review of the assessm ent to the Agency noted, in som e instances, lim itations or uncertainties that are associated with the assessm ent. These include the use of yields versus root ratings in determ ining benefits, the use of sm all plot studies to extrapolate to larger fields, and lim itations of the statistical m e thods used to com p are and analyze the available data sets.

The Agency considered the results of the benef its assessm ent together with the uncertainties present in the analysis when developing its risk reduction m easures to address occupational and ecological risks especially with regard to determ ining the appropriate level for the sales lim its considered to be a key aspect of risk m a nagem e nt.

E. Other Labeling

In order to rem a in eligible for reregistration, other use and safety inform ation need to be placed on the labeling of all end-use products containing terbufos. For the specific labeling
statem ents, refer to Section V of this docum ent

1. Endangered Species Statement

The Agency has developed the Endangered Species Protection Program to identify pesticides whose use m a y cause adverse im pacts on endangered and threatened species, and to im plem ent m itigation m easures that address these im pacts. The Endangered Species Act requires federal agencies to ensure that their actions are not likely to jeopardize listed species or adversely m odify 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 im portant ecological param e ters, pesticide use inform ation, the geographic relationship between specific pesticides uses and species locations, and biologi cal requirem e nts and behavioral aspects of the particular species. This analysis will take into consideration any regulatory changes

recom m e nded in this RED that are being im plem ented at that tim e. A determ ination that there is a likelihood of potential im pact to a listed species m a y result in lim itations on use of the pesticide, other m easures to m itigate any potential im pact, or consultations with the Fish and W ildlife 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 im plem ented on an interim basis As part of the interim program , the Agency has developed County Specific Pam phlets that articulate m a ny of

the specif i c m easures outlined in the Biological Opinions issued to date. These Pam phlets are available for voluntary use by pesticide applicators, on EPA’s web site at www.EPA.gov/espp

. A final Endangered Species Protection Program , wh ich m a y be altered from the interim program , is scheduled to be proposed for public com m e nt in the Federal Register before the end of 2001.

V. What Registrants Needs to Do

45In order to be eligible for reregistration, registrants need to im plem ent the risk m itigation

m easures outlined in Section IV and V, which include, am ong other things, subm ission of the f o llowing:

A. For terbufos technical grade active ingredient products, registrants need to subm it the f o llowing item s

. Within 90 days from receipt of the generic data call-in (DCI):

(1) com p leted response form s to the generic DCI (i.e., DCI response form and requirem e nts status and registrant’s response form ); and

(2) subm it any tim e extension and/or waiver requests with a f u ll written justif ication.

Within the time limit specified in the generic DCI:

(1) C ite any existing generic data which address data requirem e nts or subm it 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 m a terials subm itted in response to the generic DCI should be addressed:

46By US m a il: By express or courier service: Docum e nt Processing Desk (DCI/SRRD) D ocum ent Processing Desk (DCI/SRRD) Eric R. Olson E ric R.Olson US EPA (7508C) O ffice of Pesticide Program s (7508C) 1200 Pennsylvania Ave., NW Room 266A, Crystal Mall 2 W a shington, DC 20460 1921 Jefferson Davis Highway Arlington, VA 22202

B. For products containing the active ingredient terbufos , registrants need to subm it the following item s for each product.

Within 90 days from the receipt of the product-specific data call-in (PDCI):

(1) c om pleted response form s to the PDCI (i.e., PDCI response form and requirem e nts status and registrant’s response form ); and

(2) s ubm it any tim e extension or waiver requests with a f u ll written justif ication.

Within eight months from the receipt of the PDCI:

(1) t wo copies of the confidential statem ent of form ula (EPA Form 8570-4);

(2) a com p leted original application for reregistration (EPA Form 8570-1). Indicate on the form that it is an “application for reregistration”;

(3) f ive copies of the draf t label incorporating all label am endm ents outlined in Table 12 of this docum ent;

(4) a com p leted f o rm certif ying com p liance with data com p ensation requirem e nts (EPA Form 8570-34);

(5) i f applicable, a com p leted form certifying com p liance with cost share offer requirem e nts (EPA Form 8570-32); and

(6) t he 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 m a terials subm itted in response to the PDCI should be addressed:

By US m a il: By express or courier service only: Docum e nt Processing Desk (PDCI/PRB) Docum e nt Processing Desk(PDCI/PRB)

47Karen Jones K aren Jones US EPA (7508C) O ffice of Pesticide Program s(7508C) 1200 Pennsylvania Ave., NW Room 266A, Crystal Mall 2 W a shington, 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 determ ined to be substantially com p lete. The following data gaps

rem a in:

• D rinking water m onitoring data for both surface and groundwater sources for terbufos and m e tabolite levels in corn, sorghum , and sugar beet growing regions. This data is requested in order to confirm that the levels of these com pounds are lower than predicted in the Agency’s water m odels (OPPTS 167-1-SS).

• N eurotoxic 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 requirem e nts included acute, subchronic, and developm ental neurotoxicity studies; due dates are 9/2001. Registrant responses are under review.

2. Labeling Requirements for Manufacturing Use Products

To rem a in in com p liance with FIFRA, m a nufacturing use product (MUP) labeling m u st be revised to com p ly 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 af ter a determ ination of eligibility has been m a de. Registrants m u st review previous data subm issions to ensure that they m eet current EPA acceptance criteria and if not, com m it to conduct new studies. If a registrant believes that previously subm itted data m eet current testing standards, then the study MRID num bers should be cited according to the instructions in the Requirem e nt Status a nd Registrants Response Form provided for each product.

48A product-specific data call-in, outlining specific data requirem e nts, accom p anies this interim RED.

2. Labeling Requirements for End-Use Products

Labeling changes are necessary to im plem ent the m itigation m easures 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 m a y generally distribute and sell products bearing old labels/labeling for 26

m onths f r om the date of the issuance of this Interim Reregistration Eligibility Decision docum ent. Persons other than the registrant m a y generally distribute or sell such products for 50

m onths from the date of the issuance of this interim RED. However, existing stocks tim e fram es will be established case-by-case, depending on the num ber of products involved, the num ber of label changes, and other factors. Refer to “Existing Stocks of Pesticide Products; Statem ent of Policy”; Federal Register , Volum e 56, No. 123, June 26, 1991.

The Agency has determ ined that registrant m a y distribute and sell terbufos products bearing old labels/labeling for 26 m onths from the date of issuance of this interim RED. Persons other than the registrant m a y distribute or sell such products for 50 m onths from the date of the issuance of this interim RED. Registrants and persons other than the registrant rem a in obligated
to m eet pre-existing Agency im posed label changes and existing stocks requirem e nts applicable to products they sell or distribute.

49D.Required Labeling Changes Summary TableTable 10:Summary of Required Labeling Changes for TerbufosDescriptionRequired LabelingPlacement on LabelManufacturing Use ProductsFormulationInstructions required onall MUP’s“Only for formulation into an insecticide for use on corn, sugar beets, and grainsorghum.”Directions for UseOne of these statementsmay be added to a labelto allow reformulationof the product for aspecific use or alladditional usessupported by aformulator or user group“This product may be used to formulate products for specific use(s) not listed on theMUP label if the formulator, user group, or grower has complied with U.S. EPAsubmission requirements regarding support of such use(s).”“This product may be used to formulate products for any additional use(s) not listed onthe MUP label if the formulator, user group, or grower has complied with U.S. EPAsubmission requirements regarding support of such use(s).”Directions for UseEnvironmental HazardsStatements Required bythe RED and AgencyLabel Policies“Environmental Hazards”“This chemical is highly toxic to aquatic organisms (fish and invertebrates) andwildlife.Do not discharge effluent containing this product into lakes, streams, ponds,estuaries, oceans or other waters unless in accordance with the requirements of aNational Pollutant Discharge Elimination System(NPDES) permit and the permittingauthority has been notified in writing prior to discharge.Do not discharge effluentcontaining this product to sewer systems without previously notifying the local sewagetreatment plant authority.For guidance contact your state Water Board or RegionalOffice of the EPA”Directions for Use50DescriptionRequired LabelingPlacement on LabelEnd 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 AquaticOrganisms.”“For retail sale to, and use only by Certified Applicators or persons under the directsupervision of a Certified Applicator, and only for those uses covered by the CertifiedApplicator’s certification.”Top of front panelHandler PPErequirements (allformulations)Note the following information when preparing labeling for all end use products:Forsole-active-ingredientend-use products that contain terbufos the product labelmust be revised to adopt the handler personal protective equipment (PPE)/engineeringcontrol requirements set forth in this section.Any conflicting PPE requirements on thecurrent label must be removed.Formultiple-active-ingredientend-use products that contain terbufos, the handlerPPE/engineering control requirements set forth in this section must be compared withthe requirements on the current label, and the more protective language must beretained.For guidance on which requirements are considered to be more protective, seePR Notice 93-7.PPE that is established on the basis of Acute Toxicity testing with the end-use productsmust 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, theHandler PPE in this RED does not require protective eyewear which may be requiredby the Acute Toxicity testing for the end-use product.For guidance on which PPE isconsidered more protective, see PR Notice 93-7.PrecautionaryStatements Under PPERequirements51DescriptionRequired LabelingPlacement on LabelPPE Requirements“Personal Protective Equipment (PPE)”ImmediatelyEstablished by the REDfollowing/belowfor the polymer based“Some materials that are chemical-resistant to this product are” (registrant insertsPrecautionaryGranular Formulationscorrect chemical-resistant material).“If you want more options, follow theStatements:Hazards(20 CR)notmarketedinstructions for category [registrant inserts A,B,C,D,E,F,G,or H] on an EPA chemical-to Humans andin a closed loadingresistance category selection chart.”Domestic Animalssystem(Lock ‘n Load),or any other systemthat“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 arenot eligible for“In addition to the above, loaders and persons cleaning equipment must wear:reregistration if they are- chemical resistant apronnotmarketed in a- a non-powered air purifying cartridge respirator equipped with an organic vapor (OV)closed 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 allowapplication with an oil-containing material, the “N” designation must be dropped.52DescriptionRequired LabelingPlacement on LabelPPE RequirementsEstablished by the REDfor the polymer basedGranular Formulations(20 CR) marketed in aclosed loading system(Lock ‘n Load) or anyother systemthat meetsthe specifications of theWPS.Note: SLN products areonly eligible forreregistration if they aremarketed in a closedloading system.“Personal Protective Equipment (PPE)”“Some materials that are chemical-resistant to this product are” (registrant insertscorrect chemical-resistant material).“If you want more options, follow theinstructions 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 airpurifying cartridge respirator equipped withan organic vapor (OV) removing cartridgeor canister plus an N-, R- or P- series filter.”Note to Registrant:If the product contains oil or bears instructions that will allowapplication with an oil-containing material, the “N” designation must be dropped.Immediatelyfollowing/belowPrecautionaryStatements:Hazardsto Humans andDomestic Animals53DescriptionRequired LabelingPlacement on LabelPPE RequirementsEstablished by the REDfor the clay basedGranular Formulations(15 G) marketed in aclosed loading system(Lock ‘n Load) or anyother systemthat meetthe specifications of theWPS“Personal Protective Equipment (PPE)”“Some materials that are chemical-resistant to this product are” (registrant insertscorrect chemical-resistant material).“If you want more options, follow theinstructions 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 ofan engineering control is notpossible, 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 allowapplication with an oil-containing material, the “N” designation must be dropped.Immediatelyfollowing/belowPrecautionaryStatements:Hazardsto Humans andDomestic Animals54DescriptionRequired LabelingPlacement on LabelUser SafetyRequirements“Follow manufacturer'sinstructions for cleaning/maintaining PPE.If no suchinstructions for washables exist, use detergent and hot water.Keep and wash PPEseparately fromother laundry.”“Discard clothing and other absorbent materials that have been drenched or heavilycontaminated with this product’s concentrate.Do not reuse them.”PrecautionaryStatements:Hazardsto Humans andDomestic Animalsimmediatelyfollowing the PPErequirementsEngineering controls forthe polymer basedGranular Formulation(20 CR) marketed in aclosed loading system(Lock ‘n Load) or anyother closed systemthatmeets the specificationsof the WPS“Engineering Controls”“This product is formulated into a Lock ‘N Load systemthat meets the definition of aclosed loading systemin the Worker Protection Standard for Agricultural Pesticides [40CFR 170.240(d)(4)].In addition to wearing the required PPE specified above, loadersmust be provided and must have immediately available for use in an emergency, such asa broken package, spill, or equipment breakdown:coveralls,chemical resistantfootwear plus socks, a non-powered air purifying cartridge respirator equipped with anorganic 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 theWorker 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 allowapplication with an oil-containing material, the “N” designation must be dropped.PrecautionaryStatements:Hazardsto Humans andDomestic Animalsimmediatelyfollowing the UserSafety Requirements55DescriptionRequired LabelingPlacement on LabelEngineering controls forthe polymer basedGranular Formulation(20 CR)notmarketedin a closed loadingsystem(Lock ‘n Load) or anyother closed systemthatmeets the specificationsof the WPS“When handlers use enclosed cabs, in a manner that meets the requirements listed in theWorker 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.”PrecautionaryStatements:Hazardsto Humans andDomestic Animals(Immediatelyfollowing PPE andUser SafetyRequirements.)56DescriptionRequired LabelingPlacement on LabelEngineering Controls“Engineering Controls”Precautionaryfor the clay basedStatements:HazardsGranular Formulations“This product is formulated into a Lock ‘N Load systemthat meets the definition of ato Humans and(15 G) marketed in aclosed loading systemin the Worker Protection Standard for Agricultural Pesticides [40Domestic Animalsclosed loading systemCFR 170.240(d)(4)].In addition to wearing the required PPE specified above, loaders(Immediately(Lock ‘n Load), thatmust be provided and must have immediately available for use in an emergency, such asfollowing PPE andmeets the specificationsa broken package, spill, or equipment breakdown:coveralls,chemical resistantUser Safetyof the WPSfootwear plus socks, a non-powered air purifying cartridge respirator equipped with anRequirements.)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 meetsthe definition in the Worker Protection Standard for Agricultural Pesticides [40 CFR170.240(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 emergencywhen they must exit the cab in the treated area: coveralls, chemical-resistantgloves, chemical-resistant footwear, anda non-powered air purifying cartridgerespirator equipped with an organic vapor(OV) removing cartridge or canisterplus 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, toprevent contamination of the inside of the cab.”57DescriptionRequired LabelingPlacement on LabelUser SafetyRecommendations“User Safety Recommendations”“Users should wash hands before eating, drinking, chewing gum, using tobacco, orusing the toilet.Users should remove clothing/PPE immediately if pesticide gets inside.Then washthoroughly and put on clean clothing.Users should remove PPE immediately after handling this product.Wash the outside ofgloves before removing*.As soon as possible, wash thoroughly and change into cleanclothing.”PrecautionaryStatements under:Hazards to Humansand DomesticAnimals immediatelyfollowing EngineeringControls(Must be placed in abox.)Environmental Hazards“Environmental Hazards”“This pesticide is highly toxic to fish and wildlife and has been known to cause fishkills.Runoff may be hazardous to aquatic organisms in neighboring areas.Do notapply directly to water or to areas where surface water is present or to intertidal areasbelow the mean high-water mark.Keep out of lakes, ponds, and streams.Do notcontaminate water when disposing of equipment wastewater or rinsate.See Directionsfor Use for required buffer zones or setbacks.Birds and mammals may be killed ifgranules are not properly covered with soil in all areas of the treated field and inloading areas.Cover, incorporate or clean up product that is spilled during loading orthat is visible on the soil surface in turn areas.Do not apply in wet soil conditions that may prevent the equipment fromcoveringpesticide granules.Do not apply in frequently flooded areas.Under certain field and weather conditions, terbufos and its degradates have a potentialfor runoff into surface water for several weeks post-application.”PrecautionaryStatementsimmediatelyfollowing the UserSafetyRecommendations58DescriptionRequired LabelingPlacement on LabelRestricted-EntryInterval“Do not enter or allow worker entry into treated areas during the restricted entryinterval (REI) of 48 hours.The REI is 72 hours in areas where average rainfall is lessthan 25 inches per year.”Directions for Use,Agricultural UseRequirements BoxEarly Re-entry PersonalProtective Equipmentestablished by the RED.“PPE required for early entry to treated areas that is permitted under the WorkerProtection Standard and that involves contactwith anything that has been treated, suchas 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 themorally and by posting warningsigns at entrances to treated areas.”Directions for Use,Agricultural UseRequirements BoxGeneral ApplicationRestrictions“Do not apply this product in a way that will contact workers or other persons, eitherdirectly or through drift.Only protectedhandlers may be in the area during application.For any requirements specific to your State or tribe, consult the agency responsible forpesticide regulation.”Place in the Directionfor Use directly abovethe Agricultural UseBox.59DescriptionRequired LabelingPlacement on LabelOther ApplicationRestrictionsLabels must be revised to reflect the reduced the application rate on sorghum from 1.96lbs. a.i. per acreto 1.70 lbs. a.i. per acre.Labels must be revise to reflect the following loader and applicator requirements tominimize the potential for run-off to surface water:“- maintain a 500 ft. vegetative buffer between treated area and surface water onneighboring land,-maintain a 500 ft. vegetative buffer between a standpipe drain outlet and surface wateron neighboring land,-maintain a 66 ft. setback between the treated area and entry points to surface waterbodies onnon-highly erodible soils,-maintain a 300 ft. setback between the treated area and entry points to surface waterbodies on highly erodible soils,-maintain a 66 ft. setback between treated area and standpipes on terraced fields as wellas 66 ft. vegetative buffer between the tile outlet and surface water bodies.-No loading, rinsing, and washing equipment within 300 ft. fromsurface water bodiesor within 50 ft. fromwells unless conducted on an impervious surface.-all setbacks must be planted to a crop or seeded with grass or other suitable cover andall 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, andincorporate 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-cleanersappropriately to prevent rows lower in height than adjacent soil.”Place in the Directionfor Use UnderApplicationRestrictionsInstructions in theLabeling Requiredsection appearing in quotations represent the exact language that must appear on the label.Instructions in theLabeling Requiredsection not in quotes represents actions that the registrant must take to amend their labels orproduct registrations.60VI. R elated Documents and How to Access Them

This interim Reregistration Eligibility Docum e nt is supported by docum ents that are presently m a intained 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 prelim inary risk assessm ents and related docum ents as of August 7, 1998. Sixty days later the first public com m e nt period closed. The EPA then considered com m e nts, revised the risk assessm ent, and added the form al “Response to Com m e nts” docum ent and the revised risk assessm ent to the docket on Septem ber 1, 1999.

All docum ents, in hard copy form , m a y 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

62Appendix A.TABLE OF USE PATTERNS ELIGIBLE FOR REREGISTRATIONSiteApplication TypeApplicationTimingApplicationEquipmentFormulationMaximumSingleApplicationRate, aiMaximumNumber ofApplicationsPer SeasonMaximumSeasonalRate, aiMinimumSprayInterval(days)PreharvestInterval,(days)ReentryInterval(days)Use Directions and LimitationsFood/Feed Crop UsesCorn, field, pop, sweet63SiteApplication TypeApplicationTimingApplicationEquipmentFormulationMaximumSingleApplicationRate, aiMaximumNumber ofApplicationsPer SeasonMaximumSeasonalRate, aiMinimumSprayInterval(days)PreharvestInterval,(days)ReentryInterval(days)Use Directions and LimitationsBanded,InfurrowAt plantGround15% granular20% granular1.3 lb/A11.3 lb/ANA1NA2 daysBuffersto be implementedare; 1)a 500 ft.vegetative bufferbetween treated area and surface water on neighboring land, 2) a 500ft.vegetative bufferbetween a standpipe drain outlet and surfacewateron neighboring land,3)a 66 ft.setback between the treatedarea and entrypoints to surfacewater bodies on non-highlyerodiblesoils and 300 ft.on highlyerodible soils,4)a 66 ft.setback betweentreated area and standpipes on terraced fields as well as 66 ft.vegetative buffer between the tileoutlet and surface water bodies, 5)restricting loading,rinsing,and washing equipment within 300 ft.fromsurface water bodies or within 50 ft. fromwells unlessconducted on an impervious surface, 6) remove the “over the top”application forEuropean cornborercontrol,7)requireplacinggranules forbanded applicationson cornin a 7 inch band overtherow,in front of the press wheel,and incorporate into the top 1 inchof soil, and 8) the label text will be required to read “To preventchanneling ofsurface water run-off,adjust the planter row-cleanersappropriately to prevent rows lower in height than adjacent soil”.All setbacks must be planted to a crop orseeded with grass orothersuitable cover.Requirethat the Counter15G label be amended to indicate thatapplications must be made using enclosed cab tractors.Amend the North Carolina SLN registration of Counter20CR torequire the use ofa closed loading system.Sorghum, grain64SiteApplication TypeApplicationTimingApplicationEquipmentFormulationMaximumSingleApplicationRate, aiMaximumNumber ofApplicationsPer SeasonMaximumSeasonalRate, aiMinimumSprayInterval(days)PreharvestInterval,(days)ReentryInterval(days)Use Directions and LimitationsBanded,KnifedInAt bedding,atplantGround15% granular20% granular1.7 lb/A11.7lb/ANANA2 daysBuffersto be implemented are; 1)a 500 ft.vegetative bufferbetween treated area and surface water on neighboring land, 2) a 500ft.vegetative bufferbetween a standpipe drain outlet and surfacewateron neighboring land,3)a 66 ft.setback between the treatedarea and entrypoints to surfacewater bodies on non-highlyerodiblesoils and 300 ft.on highlyerodible soils,4)a 66 ft.setback betweentreated area and standpipes on terraced fields as well as 66 ft.vegetative buffer between the tileoutlet and surface water bodies, 5)restricting loading,rinsing,and washing equipment within 300 ft.fromsurface water bodies or within 50 ft. fromwells unlessconducted on an impervious surface, 6) the label text will berequired to read “To prevent channeling ofsurface water run-off,adjust the planter row-cleaners appropriately to prevent rows lowerin height than adjacent soil”.Allsetbacks must be planted to a croporseeded with grass orothersuitable cover.Requirethat the Counter15G label be amended to indicate thatapplications must be made using enclosed cab tractors.Sugar beets65SiteFormulationMaximumMaximumMaximumMinimumPreharvestReentryUse Directions and LimitationsApplication TypeSingleNumber ofSeasonalSprayInterval,IntervalApplicationTimingApplicationRate, aiApplicationsPer SeasonRate, aiInterval(days)(days)(days)ApplicationEquipmentBanded,15% granular1.97 lb/A11.97 lb/ANANA2 daysBuffersto be implemented are; 1)a 500 ft.vegetative bufferModified Infurrow, Knifed20% granularbetween treated area and surface water on neighboring land, 2) a 500ft.vegetative bufferbetween a standpipe drain outlet and surfaceInwateron neighboring land,3)a 66 ft.setback between the treatedAt plantGroundarea and entrypoints to surfacewater bodies on non-highlyerodiblesoils and 300 ft.on highlyerodible soils,4)a 66 ft.setback betweentreated area and standpipes on terraced fields as well as 66 ft.vegetative buffer between the tileoutlet and surface water bodies, 5)restricting loading,rinsing,and washing equipment within 300 ft.fromsurface water bodies or within 50 ft. fromwells unlessconducted on an impervious surface, 6) the label text will berequired to read “To prevent channeling ofsurface water run-off,adjust the planter row-cleaners appropriately to prevent rows lowerin height than adjacent soil”.Allsetbacks must be planted to a croporseeded with grass orothersuitable cover.Requirethat the Counter15G label be amended to indicate thatapplications must be made using enclosed cab tractors.Non-Food/Non-Feed Crop UsesCorn, field grown for seed66SiteFormulationMaximumMaximumMaximumMinimumPreharvestReentryUse Directions and LimitationsApplication TypeSingleNumber ofSeasonalSprayInterval,IntervalApplicationTimingApplicationRate, aiApplicationsPer SeasonRate, aiInterval(days)(days)(days)ApplicationEquipmentBanded,In15% granular1.3 lb/A11.3lb/ANANA2 daysBuffersto be implemented are; 1)a 500 ft.vegetative bufferfurrowAt plantGround20% granularbetween treated area and surface water on neighboring land, 2) a 500ft.vegetative bufferbetween a standpipe drain outlet and surfacewateron neighboring land,3)a 66 ft.setback between the treatedarea and entrypoints to surfacewater bodies on non-highlyerodiblesoils and 300 ft.on highlyerodible soils,4)a 66 ft.setback betweentreated area and standpipes on terraced fields as well as 66 ft.vegetative buffer between the tileoutlet and surface water bodies, 5)restricting loading,rinsing,and washing equipment within 300 ft.fromsurface water bodies or within 50 ft. fromwells unlessconducted on an impervious surface, 6) remove the “over the top”application forEuropean cornborercontrol,7)requireplacinggranules forbanded applicationson cornin a 7 inch band overtherow,in front of the press wheel,and incorporate into the top 1 inchof soil, and 8) the label text will be required to read “To preventchanneling ofsurface water run-off,adjust the planter row-cleanersappropriately to prevent rows lower in height than adjacent soil”.All setbacks must be planted to a crop orseeded with grass orothersuitable cover.Requirethat the Counter15G label be amended to indicate thatapplications must be made using enclosed cab tractors.Amend the North Carolina SLN registration of Counter20CR torequire the use ofa closed loading system.1NA: Not applicable67Appendix B.TABLE OF GENERIC DATA REQUIREMENTS AND STUDIES USED TO MAKE THEREREGISTRATION DECISIONGUIDE TO APPENDIX BAppendix B contains listing of data requirements which support the reregistration for active ingredients within the case terbufoscovered by this RED.It contains generic data requirements that apply terbufos in all products, including data requirements for which a"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 in 40 CFR part 158.the reference numbers accompanying each test refer to the test protocols set in the Pesticide Assessment Guidance, whichare available fromthe National technical InformationService, 5285 Port Royal Road, Springfield, VA 22161 (703) 487­4650.2.Use Pattern(Column 2).This columnindicates the use patterns for which the datarequirements apply.The following letter designations are used for the given use patterns.A.Terrestrial foodB.TerrestrialfeedC.Terrestrial non-foodD.Aquatic foodE.Aquatic non-food outdoorF.Aquatic non-food industrialG.Aquatic non-food residentialH.GreenhousefoodI.Greenhouse non-foodJ.Forestry68K.ResidentialL.Indoor foodM.Indoor non-foodN.Indoor medicalO.Indoor residential3.Bibliographic Citation (Column 3).If the Agency has acceptable data in its files, this columnlist the identify number ofeach study.This normally is the Master RecordIdentification (MIRD) number, but may be a "GS" number if no MRID number has been assigned.Refer to theBibliography appendix for a complete citation of the study.69APPENDIX BData Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)PRODUCT CHEMISTRYNewOldGuidelineGuidelineNumberNumber830.155061-1Product Identity andAll43147501, 41297901Composition830.160061-2AStart. Mat. & Mnfg.All41049501Process830.167061-2BFormation ofAll41049501Impurities830.170062-1Preliminary AnalysisAll41297902830.175062-2Certification ofAll43147502, 41297902limits830.180062-3Analytical MethodAll43147503, 41297902830.630263-2ColorAll41049502830.630363-3Physical StateAll41049502830.630463-4OdorAll41049502830.7050NoneUV/Visable AbsorptionAll830.720063-5Melting PointAll4104950270Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)830.722063-6Boiling PointAll41049502830.7860Partition CoefficientActioncharacteristicsECOLOGICAL EFFECTS830.730063-7DensityAll41049502830.784063-8SolubilityAll41049502830.795063-9Vapor PressureAll41049502830.737063-10Dissociation ConstantAll41049502830.755063-11Octanol/WaterAll41049502830.700063-12pHAll41049502830.631363-13StabilityAll41049502830.631463-14Oxidizing/ReducingAll41049502,43147503830.631563-15FlammabilityAll41049502830.631663-16ExplodabilityAll41049502830.631763-17Storage StabilityAll41049502830.710063-18ViscosityAll41049502830.631963-19MiscibilityAll41049502830.632063-20CorrosionAll4104950271Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)850.210071-1Avian Acute OralToxicity TestFEOTER02850.220071-2Avian Dietary ToxicityTest00035120, 00087717, 00160387850.230071-4Avian ReproductionTest00097892, 00161574, 00191573None71-5ASimulated Field StudyFEOTER01,00085179, 00085183,40985501, 40993501, 41475801,41508801, 41849201None71-5BTerrestrial FieldStudyBAOTER01,00085178, 00085180,00087726850.107572-1Fish Acute ToxicityFEOTER04, FEOTER05, 00037483,00085176, 00087718950.101072-2Aquatic InvertebrateFEOTER03, 00085176None72-3AEstuarine/MarineToxicity - Fish41373602, 41373603None72-3BEstuarine/MarineToxicity - Mollusk00162524, 42381501None72-3CEstuarine/MarineToxicity - Shrimp00162523, 41297903None72-4AFish- Early Life Stage00162525, 40009301, 41475802850.150072-5Life Cycle FishReserved72Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)None72-6Aquatic Org.AccumulationWaived, 41373603850.195072-7ATOXICOLOGYSimulated FieldAquatic OrganismsWaived870.110081.1Acute Oral-Rat00029863870.120081-2Acute Dermal-Rabbit258710870.130081-3Acute Inhalation-Rat41538101870.240081-4870.250081-5Primary Eye IrritationPrimary SkinIrritation004495700044957870.260081-6Dermal Sensitization44942302870.610081-7870.620081-8870.310082-1870.320082-2870.346582-4Delayed NeurotoxicityAcute NeurotoxicitySubchronic 90 Day OralToxicity21-Day Dermal ­Rabbit/RatSubchronic InhalationToxicity00037472446720034484230200085169, 40374701, 44450600,44450601, 44520501, 446905010025871073Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)870.410083-1Chronic Toxicity00263678, 40374701870.370083-3ADevelopmental00147533Toxicity-Rat870.370083-3BDevelopmental Toxicity00147533, 40886301,40966401- Rabbit870.380083-42-Generation00085172, 43649402Reproduction - Rat870.430083-5Combined Chronic00049236, 40089602, 40089603Toxicity/Carcinogenicity870.748585-1General Metabolism42348801OCCUPATIONAL/RESIDENTIAL EXPOSURE875.2100132-1AFoliar ResidueDissipation875.2400133-3Dermal PassiveDosimetry Exposure875.2500133-4Inhalation PassiveWaivedDosimetry ExposureENVIRONMENTAL FATE835.2120161-1Hydrolysis of Parent44862501and Degradates74Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)835.2240161-2Photodegradation -Water00161567, 41181101835.2410161-3Photodegradation -SoilWaived835.2370161-4Photodegradation - AirWaived835.4100162-1Aerobic SoilMetabolism00156853835.4200162-2Anaerobic SoilMetabolism41749801835.4300162-4Aerobic AquaticMetabolism44672004, 44862502835.1240163-1Leaching/Adsorption/Desorption41373604835-1410163-2Volatility-LabWaived835-8100163-3Volatility-SoilReserved835.6100164-1Terrestrial FieldDissipation41883100, 44381201835-6500164-5Long-Term SoilDissipationReserved860-1900165-2Field Rotational Crop4094070175Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTNone165-4Bioaccumulation inFishRESIDUE CHEMISTRY860-1200171-3Directions for Use860.1300171-4BNature of Residue -LivestockUSE PATTERNCITATION(S)41373603, 4137360541475803, 41475804, 42576900860.1340860.1340860.1380860.1480860.1500860.1500860.1500171-4C171-4D171-4E171-4J171-4K171-4K171-4KResidue AnalyticalMethod - PlantsResidue AnalyticalMethod - AnimalsStorage StabilityMagnitude of Residues- Meat/Milk/Poultry/EggCrop Field Trials(Sugar Beets)Crop Field Trials(Corn-Field)Crop Field Trials(Sorghum)41475804Reserved40940701, 41373606, 43237800,43649401, 44464601Reserved41569401, 4426794195560141569402, 4266180176Data Supporting Guideline Requirements for the Reregistration of TerbufosREQUIREMENTUSE PATTERNCITATION(S)860.1520171-4L860.1520171-4LOTHERProcessed Foods (Corn,Field)Processed Foods(Sorghum, Grain)41955601, 4323780041569402, 43237800None82-3SSHuman Incident DataNone163-ASSMonitoring Studies-Soil870-6200870,6200870-6300NoneNoneNoneNeurotox ScreeningBattery-AcuteNeurotox ScreeningBattery-AcuteDevelopmental Neurotox77Appendix C. TECHNICAL SUPPORT DOCUMENTS

Additional docum entation in support of this RED is m a intained in the OPP docket, located in Room 119, Crystal Mall #2, 1921 Jefferson Davi s Highway, Arlington, VA. It is open Monday through Friday, excluding legal holidays, from 8:30 am to 4 pm

.

The docket initially contained prelim inary risk assessm ents and related docum ents as of August 10, 1998. Sixty days later the first public com m e nt period closed. The EPA then considered com m e nts, revised the risk assessm ent, and added the form al “Response to Com m e nts” docum ent and the revised risk assessm ent to the docket on June 16, 1999.

All docum ents, in hard copy form , m a y be viewed in the OPP docket room or downloaded or viewed via the Internet at the following site:

www.epa.gov/pesticides/op

These docum ents include:

HED Docum e nts:

3. Organophosphate Pesticides: Terbufos Availability of Revised Risk Assessm ent (FR Notice)
4. Hum a n Health Risk Assessm ent: Terbufos
5. Terbufos Toxicology Chapter for RED
6. Terbufos: Revised Acute and Chroni c Dietary Exposure Analyses for the HED Revised Risk Assessm ent 7. Terbufos: Revised Probabilistic (Monte Carlo) Dietary Exposure Analysis and Supporting Docum e ntation
8. Terbufos: Revised Probabilistic (Monte Carlo) Acute Dietary Exposure and Risk
9. Terbufos: Com p rehensive Report of the Toxicological Endpoints Selection Report of the Hazard Identification Assessm ent Review Com m ittee (HIARC)
10. Terbuf os: Report of the FQPA Saf e ty Factor Com m ittee
11. The Revised Occupational and Residential Exposure Aspects of the HED Chapter of the RED for Terbufos

EFED Docum e nts:

7812. Terbufos: Revised EFED RED Chapter Revision of Fate and Transport and W a ter Resources

79Appendix 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 bib liography contains citations of all studies considered relevant by EPA in arriving at the positions and conclusions stated elsewhere in the Reregistration Eligibility Docum e nt. Prim ary sources f o r studies in this bibliography have been the body of data subm itted to EPA and its predecessor agencies in support of past regulatory decisions. Selections f r om 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 m a terials, this corresponds closely to an article. In the case of unpublished

m a terials subm itted to the Agency, the Agency has sought to identify docum ents at a level parallel to the published article f r om within the typically larger volum es in which they were subm itted. 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 attem p ted to unite basic docum ents and

com m e ntaries upon them , treating them as a single study.

3. IDENTIFICATION OF ENTRIES. The entries in this bibliography are sorted num erically by Master Record Identifier, or "MRID” num ber. This num ber is unique to the citation, and should be used whenever a specific reference is required. It is not related to the sixdigit "Accession Num b er" which has been used to identif y volum es of subm itted studies (see paragraph 4(d)(4) below for further explanation). In a few cases, entries added to the bibliography late in the review m a y be preceded by a nine character tem porary identifier. These entries are listed af ter all MRID entries. This tem porary identif ying num ber 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 elem ents followed, in the case of m a terial subm itted to EPA, by a description of the earliest known subm ission. Bibliographic conventions used reflect the standard of the Am erican National Standards Institute (ANSI), expanded to provide for certain special needs.

a A uthor. W h enever the author could confidently be identified, the Agency has chosen to show a personal author. W h en no individual was identified, the Agency has shown an identif iable laboratory or testing f acility as the author. W h en no author or laboratory could be identif ied, the Agency has shown the f i rst subm itter as the author.

80b. Docum e nt date. The date of the study is taken directly from the docum ent. W h en the date is followed by a question m a rk, the bibliographer has deduced the date from the evidence contained in the docum ent. W h en the date appears as (1999), the Agency was unable to determ ine or estim ate the date of the docum ent.

c. Title. In som e cases, it has been necessary for the Agency bibliographers to create or enhance a docum ent title. Any such editorial insertions are contained between square brackets.

d. Trailing parentheses. For studies subm itted to the Agency in the past, the trailing parentheses include (in addition to any self-explanatory text) the following elem ents describing the earliest known subm ission:

(1) S ubm ission date. The date of the earliest known subm ission appears im m e diately following the word "received."

(2) A dm inistrative num ber. The next elem ent im m e diately following the word "under" is the registration num ber, experim e ntal use perm it num ber, petition

num ber, or other adm i nistrative num ber associated with the earliest known subm ission.

(3) S ubm itter. The third elem ent is the subm itter. W h en authorship is def a ulted to the subm itter, this elem ent is om itted.

(4) V olum e Identification (Accession Num b ers). The final elem ent in the trailing parentheses identifies the EPA accession num ber of the volum e in which the original subm ission of the study appears. The six-digit accession

num ber follows the sym bol "CDL," which stands for "Com pany Data Library." This accession num ber is in turn followed by an alphabetic suffix which shows the relative position of the study within the volum e.

81

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MRID CITATION



### ____________________________________________________
00029863 Consultox Laboratories (1975) Acut e Oral and Percutaneous Toxicity Evaluations. (Unpublished study received Feb 3, 1976 under 2749-425; subm itted by Aceto Chem ical 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 Sym bol 2749 UEL to Mallard Duck: Laboratory No. 8E-3451. (Unpublished study received Mar 27, 1979 under 2749-425; prepared by Cannon Laboratories, Inc., subm itted by Aceto Chem ical 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 Tim e and Planting Ti m e plus Cultivation Tim e Treatm ents: Arcola, Illinois--1972: Report No. 72-43. (Unpublished study received Apr 9, 1973 under 3G1340; subm itted by Am erican Cyanam id 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; subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:093580-J)

00036214 Thom pson, J.P.; Sakam o to, S.S.; Tucker, B.V.; et al. (1973) Sum m a ry: Paraquat: Tem porary Residue Tolerance Petition--Sunflower. (Unpublished study received May 24, 1973 under 3G1396; subm itted by Chevron Chem ical Co., Richm ond, Calif.; CDL: 095381-B)

00036238 Fagan, E.B.; Owens, J.; W e is, M.E.; et al. (1972) AC 92,100 Residue Study on Field Corn. Planting Tim e and Planting Tim e plus cultivation Tim e Treatm e nts: Am es, Iowa: Report No. 72-47. (Unpublished study received Apr 9, 1973 under 3G1340; prepared in cooperation with Iowa State Univ., Dept. of Entom o logy and Zoology, subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL: 093581-G)

00037472 Sm ith, 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/dynam i cs, Inc. subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL: 093584-H)

82

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MRID CITATION



### ____________________________________________________
00037483 Sleight, B.H., III (1972) The Acute Toxicity of Cycocel^(R) 4 and Experim e ntal Insecticide AC 92,100 to Bluegill (~Lepom is m ac~μ-μ~rochirus~μ) and Rainbow Trout (~Salm o gairdneri~μ). (Unpublished study received Apr 9, 1973 under 3G1340; prepared by Bionom ics, Inc., subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:093584-U)

00042017 Am erican Cyanam id Com p any (1973) Sum m a ry--Counter-Related Residues in Corn. (Unpublished study received May 1, 1974 under 4F1496; CDL:091452-A)

00042018 Am erican Cyanam id Com p any (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 m e thod 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, subm itted by Am erican Cyanam id 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 Com m odities: Im m a ture Plant, Harvest Plant and Harvest Beans (Kansas and Iowa): Report No. C-429. Includes m e thod M-480 dated Jan 9, 1974. (Unpublished study received May 1, 1974 under 4F1496; prepared in cooperation with Farm land Industries and Iowa State Univ., Dept. of Zoology & Entom o logy, subm itted by Am erican Cyanam id 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 Sam p les W h en Stored in the Frozen State: Report No. C-430. Includes m e thod M-336 dated Jun 21, 1972. (Unpublished study received May 1, 1974 under 4F1496; subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:091452-F)

00042022 Manuel, A.J. (1973) Counter (CL 92,100): Confirm a tory Gas-Liquid Chrom a tography Test for Counter Residues in Corn Grain and Forage, and in Anim al Tissues: Report No. C-379. Includes m e thod M-460 dated Sep 27, 1973. (Unpublished study received May 1, 1974 under 4F1490; subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:091452-G)

83

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MRID CITATION



### ____________________________________________________
00044957 Am erican Cyanam id Com p any (1972) Toxicity Da ta of O,O-Diethyl S(tert.-butylthiom e thyl) phosphorodithioate: Report A-72-3. (Unpublished study received Aug 1, 1974 under 241-241; CDL: 100877-A)

00049236 Rapp, W

. R.; W ilson, N.H.; Mannion, M.; et al. (1974) A Three and Twenty-Four Month Oral Toxicity and Carcinogenic ity Study of AC 92,100 in Rats: Project No. 71R-725. (Unpublished study received May 29, 1975 under 241-238; prepared by Biodynam i cs, Inc., subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL: 224096-A)

00085167 Am erican Cyanam id Com p any (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.; Feinm a n, H.; (1973) 30-day Subacute Derm al 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., subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:090808-J)

00085172 Sm ith, J.M.; Kasner, J.A.; W ilson, 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/dynam i cs, Inc., subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:090808-M)

00085176 Bentley, R.E. (1973) Acute Toxicity of Counter^(TM) 4 to Bluegill (μ~Lepom is

m acrochirus~μ), Channel Catfish (μ~Ict alurus punc~μ-μ~tatus~μ) and Crayfish (μ~Procam barus clarkii~μ). (Unpublished study received May 1, 1974 under 4F1496; prepared by Bionom ics, Inc., subm itted by Am erican Cyanam id 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 W ildlife. (Unpublished study received May 1, 1974 under 4F1496; prepared by Illinois Natural History Survey, subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:090808-T)

00085179 Labisky, R.F. (1974) Responses of Confined Hen Pheasants to Sim u lated Field Applications of Counter^(R) 4 Soil Insecticide. (Unpublished study received May

84

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MRID CITATION



### ____________________________________________________ 1, 1974 under 4F1496; prepared by Illinois Natural History Survey, subm itted by Am erican Cyanam id 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 W ildlife Tissues and Eggs: Report No. C-377. (Unpublished study received May 1, 1974 under 4F1496; subm itted by Am erican Cyanam id 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; subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL: 090808-Y)

00087717 Roberts, S.; W i neholt, 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., subm itted by Aceto Chem ical Co., Inc., Flushing, N.Y.; CDL:226950-A)

00087718 Roberts, S.; W i neholt, R.L. (1976) St atic 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., subm itted by Aceto Chem ical Co., Inc., Flushing, N.Y.; CDL:226951-A)

00087726 W a ng, G.T. (1973) Letter sent to Harold H. Nau dated Jun 21, 1973: Post-m ortem

exam ination--wildlife. (Unpublished study received on unknown date under unknown adm i n. no.; subm itted by Am erican Cyanam id Co., Princeton, N.J.; CDL:223457-A)

00091452 See MRID Num b ers 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 Environm ental Sciences Corp., subm itted by Am erican Cyanam id 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

### BIBLIOGRAPHY

MRID CITATION



### ____________________________________________________ received Aug 5, 1982 under 241-238; prepared by Bio/dynam i cs, Inc., subm itted by Am erican Cyanam id Co., Princeton, NJ; CDL:247985-A)

00144805 Fischer, J. (1985) Rabbit Derm al LD50 (Intact Skin): Report No:A85-54. Unpublished study prepared by Am erican Cyanam id Co. 3 p.

00144806 Rusch, G. (1980) A Two W eek Inhala tion Toxicity Study of Technical Counter Terbufos in the Rat: Project No. 78-7168. Unpublished study prepared by Bio/Dynam i cs 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 Am erica, Inc. 62 p.

00147533 Rodwell, D. (1985) A Teratology Study with AC 92, 100 in Rats: Project No. W I L-35014: Final Report. Unpublished study prepared by W I L Research Laboratories, Inc. 212 p.

00147534 Am erican Cyanam id Co. (1983) Sam p le Identification, Purity and Minor Com ponent Profile ? Counter Terbufos σ

. Unpublished study. 28 p.

00156853 Peterson, R. (1983) Counter Ter bufos (CL 92,100): Aerobic and Anaerobic Metabolism of CL 92,100 in a Silt Loam Soil: Project No. 0402: Report No. PD-M Volum e 20-4. Unpublished study prepared by Am erican Cyanam id Co. 52 p.

00158606 Higham
, J. (1984) Counter Terbuf os (CL 92,100/10-G): Residues of Total CL 92,100-related Residues in W hole Banana s (GND; Costa Rica, 1983) (C-2260): Report No. C-2438. Unpublished study prepared by Am erican Cyanam id Co. with sum m a ry 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 Com pounds in W hole Bananas (GND; Costa Rica, 1984) (C-2260): Report No. C-2494. Unpublished study prepared by Am erican Cyanam id 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 Com pounds in Bananas (GND; Costa Rica, 1984) (C-2260): Report No. C-2621. Unpublished study prepared by Am erican Cyanam id Co. 10 p.

00158609 Bohn, W

. (1984) Counter Terbufos (CL 92,100/10-G): Residues of Total CL 92,100-related Com pounds in W hole Bananas (GND; Costa Rica, 1984) (C-2260): Report No. C-2493. Unpublished study prepared by Am erican Cyanam id Co. 7 p.

00158610 Bohn, W

. ; Behm , J. (1986) Counter Terbufos (CL 92,100/10-G): Residues of Total CL 92,100-related Com pounds in Bananas (GND; Costa Rica, 1984) (C-2260): Report No. C-2674. Unpublished study prepared by Am erican Cyanam id Co. 16 p.

00158611 Khunachak, A.; Behm , J. (1986) C ounter Terbufos (CL 92,100/10-G): Residues of Total CL 92,100-related Com pounds in W hole Banana (GND; Costa Rica, 1985) (C-2260): Report No. C-2705. Unpublished study prepared by Am erican Cyanam id Co. 15 p.

00158612 Khunachak, A.; Behm , J. (1986) C ounter Terbufos (CL 92,100/10-G): Residues of Total CL 92,100-related Com pounds in W hole Banana, Peel and Pulp (GND; Costa Rica, 1985) (C-2260): Report No. C-2704. Unpublished study prepared by Am erican Cyanam id Co. 14 p.

00158613 Khunachak, A.; Behm , J. (1986) C ounter Terbufos (CL 92,100/10-G): Residues of Total CL 92,100-related Com pounds in W hole Banana, Peel and Pulp (GND; Honduras, 1985) (C-2260): Report No. C-2706. Unpublished study prepared by Am erican Cyanam id Co. 13 p.

00158614 Elenewski, C. (1983) Counter Ter bufos (CL 92,100): Validation of GC Method M-1340 for the Determ ination of Total CL 92,100-related Residues in W hole Bananas: Report No. C-2260. Unpublished study prepared by Am erican Cyanam id 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 W ildlife 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 BioChem istry Laboratories, Inc. 2 p.

00161567 Mangels, G. (1986) Counter Insecticide, Terbufos (CL 92,100): W a ter Photolysis: Report No. PD-M 23-19: Project No. 0112. Unpublished study prepared by Am erican Cyanam id 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 Am erican Cyanam id Co. Report No. 981-84-118 prepared by Tegeris Laboratories, Inc. 836
p.

00161574 Beavers, J. (1986) Counter Tec hnical: A One-generation Reproduction Study with the Mallard (Anas platyrhynchos): Final Report: Project No. 130-138. Unpublished study prepared by W ildlife International Ltd. 129 p.

00162523 Forbis, A.; Schoen, L.; Leak, T.; et al. (1986) Acute Toxicity of ? Carbon 14 σ -CL 92,100 to Mysid Shrim p (Mysidopsis bahia): Final Static Acute Toxicity Report #32890. Unpublished study prepared by Anal ytical Bio-Chem istry Laboratories, Inc. 246 p.

00162524 Swigert, J.; McAllister, W

. ; Bowm an, J.; et al. (1986) Acute Toxicity of ? Carbon 14 σ -CL 92, 100 to Sheepshead Minnows (Cyprinodon variegatus): Final Static Acute Toxicity Rept. #32889. Unpublished study prepared by Analytical Bio-Chem istry Laboratories, Inc. 279 p.

00162525 Forbis, A.; Land, C.; Bunch, B. (1986) Chronic Toxicity of CL 92, 100 to Daphnia m a gna Under Flow-Through Test Conditions: ABC Final Rept. #32891. Unpublished study prepared by Analytical Bio-Chem istry Laboratories, Inc. 164
p.

00258710 See MRID Num b ers 00144805 to 00144806

00258787 See MRID Num b ers 00147532 to 00147534

88

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MRID CITATION



### ____________________________________________________
00262634 See MRID Num b ers 00158606 to 00158614

00263678 See MRID Num b ers 00161566 and 00161572

40009301 McAllister, W

. (1986) Early Life Stage Toxicity of ? Carbon 14 σ -CL 92100 to Rainbow Trout (Salm o gairdneri) in a Flow-through System : Fish Early Life Stage Study: Study No. 34267: Final Report. Unpublished study prepared by Analytical Bio-Chem istry Laboratories, Inc. 382 p.

40089603 Shellenberger, T. (1986) Chronic Diet ary 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) Determ ination of Fenarim o l 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 Com pounds in Coffee Beans (Costa Rica): Report Nos. C-2459 and C-2351. Unpublished study prepared by Am erican Cyanam id 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 Hoberm an, A. (1988) A Developm ental Toxicity (Em b ryo-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 Residue s: Report No. C-3107: Project No. 0107. Unpublished study prepared by Am erican Cyanam id Co. 10 p.

89

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MRID CITATION



### ____________________________________________________
40966401 Hoberm an, A. (1988) Addendum to Developm ental Toxicity (Em b ryofetal Toxicity/Teratogenicity): Study with AC 92,100 in Rabbits: (Sam ple 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-Anders on, L.; et al. (1989) Laboratory, Sim u lated, and Actual Field Testing to Assess the Im pacts of Counter on Non-target Organism s: Project No. 107. Unpublished com p ilation prepared by The Institute of W ildlife Toxicology. 985 p.

40993501 Brewer, L.; Cobb, G.; Hooper, M.; et al. (1989) Thrid Year Investigation of the Response of Selected W ildlife Populations to Planting Tim e Application of Counter 15-G System ic Insecticide-Nem a ticide in an Iowa Corn Agroecosystem : Am erican Cyanam id Co. Protocol Nos. 985-87-101.1. Unpublished study prepared by The Institute of W ildlife Toxicology. 283 p.

41049501 Am erican Cyanam id Co. (1989) De scription of Beginning Materials and Manuf acturing Process and Discussion of Form ation of Im purities f o r Conter Technical. Unpublished com p ilation. 83 p.

41049502 Am erican Cyanam id Co. (1989) Physical and Chem ical Characteristics for Counter Technical. Unpublished study. 128 p.

41181101 Mangels, G. (1989) Terbufos (AC 92, 100): Photodegradation in W a ter: Laboratory Project ID: E-89-14: Report No. PD-M Volum e 26-37. Unpublished study prepared by Am erican Cyanam id Co. 57 p.

41297902 W ilson, L.; Galley, M. (1989) Certification of Lim its and Analytical Method To Verify Certified Lim its: Counter: Method Num b er M-1913. Unpublished study prepared by Am erican Cyanam id Co. 53 p.

41297903 Forbis, A. (1989) Acute Flow-t hrough Toxicity of Carbon-14-AC 92,100 to Mysid Shrim p (Mysidopsis bahia): Final Report: Lab Project Num b er 37912; 971-89-135. Unpublished study prepared by Analytical Bio-chem istry Laboratories, Inc. 235 p.

41373602 Bowm an, J. (1989) Acute Flow-through Toxicity of [Carbon 14]-AC 92, 100 to Sheepshead Minnow (Cyprinodon variegat us): ABC Laboratory Project ID:

90

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MRID CITATION



### ____________________________________________________
37911. Unpublished study prepared by Anal ytical Bio-Chem istry Laboratories, Inc. 240 p.

41373603 W u, J. (1989) Terbufos (CL 92,100): Metabolic Fate of [Carbon 14]-CL 92,100 in Bluegill Sunfish (Lepom is m acrochirus): XBL Report No. RPT00018. Unpublished study prepared by XenoBiotic Laboratories, Inc. 43 p.

41373604 Mangels, G. (1989) Adsorption/Deso rption 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 Am erican Cyanam id Co. 119
p.

41373605 Burgess, D. (1989) Uptake, Depura tion and Bioconcentration of [Carbon 14]-AC 92,100 by Bluegill Sunfish (Lepom is m acrochirus): ABC Laboratory Project ID: 37914. Unpublished study prepared by Anal ytical Bio-Chem istry 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 Am erican Cyanam id Co. 17 p.

41475801 Tank, S.; Brewer, L.; Cobb, G.: et al. (1990) Third Year Investigation of the Response of Selected W ildlife Populations to Planting Tim e Application of Counter 15G System ic Insecticide-nem a ticide in an Iowa Corn Agroecosystem : Project Num b er 107. Unpublished study prepared by The Institute of W ildlife & Environm ental Toxicology. 753 p.

41475802 Rhodes, J.; McAllister, W

. (1990) Early Life Stage Toxicity of [Carbon 14]-AC 92,100 to the Rainbow Trout (Oncorhynchus m ykiss) under Flow-through Conditions: Final Report # 37913. Unpublished study prepred by Analytical Bio-Chem istry 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 Volum e 27-3. Unpublished study prepared by Am erican Cyanam id Co. 144 p.

91

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### ____________________________________________________
41475804 Brindle, P. (1990) Terbufos (CL 92,100): 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 Volum e 27-13. Unpublished study prepared by Am erican Cyanam id Co. 127 p.

41508801 Pedersen, C. (1990) Counter System ic Insecticide-nem a ticide: A Sim u lated (Pen) Field Study to Assess the Availability, Persistence and Toxicity of Counter Form ulations to Brown-Headed Cowbirds (Molothrus ater) and Bobwhite Quail (Colinus virginianus): Lab. Project Num b er: BLAL #89 SP 17: CYANAMID 971-89-123. Unpublished study prepared by Bio-Life Associates, Ltd. 166 p.

41538101 Hoffm an, G. (1987) An Acute Inhalation Toxicity Study with AC 92,100 in Rats: Bio/dynam i cs, Inc. Project No. 86-7970. Unpublished study prepared by Bio/dynam i cs, Inc. 244 p.

41569401 Kleiner, A. (1990) CL92,100 (Ter bufos/15-G): Residues of Total CL 92,100-Related Com pounds in Sugarbeet Roots and Foliage: Lab Project Num b er: C3366: C3367: C3368. Unpublished study prepared by Am erican Cyanam id Co. 135 p.

41569402 Kleiner, A. (1990) CL 92,100(Terbufos /15G): Residues of Total CL 92,100-Related Com pounds in Grain Sorghum : Lab Project Num b er: C3374: C3375: C3376. Unpublished study prepared by Am erican Cyanam id Co. 103 p.

41749801 Madsen, S.; W illiam s , M. (1990) "Anaerobic Soil Metabolism of 14c-Terbufos": Lab Project Num b er: 38612. Unpublished study prepared by Analytical Bio-Chem istry Laboratories, Inc. 53 p.

41849201 Kendall, R. (1991) Chem ical and Bioc hem i cal Analysis of Sam p les from the Study "COUNTER System ic Insecticide-Nem a ticide: A Sim u lated (Pen) Field Study to Assess the Availabilty, Persistence, and Toxicity of COUNTER Form ulations to Brown-headed Cowbirds (Molothrus ater) and Bobwhite Quail (Colinus virginanus)": Supplem ent to MRID 41508801: Lab Project Num b er: BLAL #SP 17: 971-89-123. Unpublished study prepared by Clem son Univ., Institute of W ildlife and Environm ental Toxicology. 93 p.

41883100 Am erican Cyanam id Co. (1991) Subm ission of Data to Support the Registration Standard of Terbuf os: Environm ental Fate Data. Transm ittal of 2 Studies.

92

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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 Com pounds (CL 94,301 and CL 94,320) in California: Lab Project Num b er: C3532. Unpublished study prepared by Am erican Cyanam id Co. 160 p.

41883102 Higham
, J. (1991) Terbufos (CL 92,100): Validation of GLC Method M-1912 for the Determ ination of Terbufos (CL 92,100) and Related Com pounds (CL 94,301 and CL 94,320) in Soil: Lab Project Num b er: C3544. Unpublished study prepared by Am erican Cyanam id Co. 76 p.

41955601 Leonard, R. (1991) CL92,100(Terbuf os/15G): Residues of Total CL92, 100-Related Residues in Field Corn after Application at the Mininum Labelled Use Rate and 5X the Maxim um Labelled Use Rate (At Cultivation; 1990): Lab Project Num b er: C3566: C3567: C3568. Unpublished study prepared by Am erican Cyanam id Co. 248 p.

42267901 Glaza, S. (1992) Acute Derm al Toxic ity Study of Vinyzene RP-1000 Granulated in Rabbits: Lab Project Num b er: HW I 11205765. Unpublished study prepared by Hazleton W i sconsin, Inc. 28 p.

42348801 Cheng, T. (1992) Metabolism of [carbon 14]-Terbufos (CL 92,100) in Rats: Prelim inary and Def i nitive Phases: Final Report: Laboratory Project Num b er: HW I 6123-164. Unpublished study prepared by Hazleton W i sconsin, Inc. 203 p.

42381501 Sved, D.; W i sk, 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 Num b er: 130A-104A: 941-91-151. Unpublished study prepared by W ildlife International Ltd. 93 p.

42576900 Am erican Cyanam id Co. (1992) Subm ission of residue data in support of the Terbufos registration standard. Transm ittal 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 Num b er: HW I 6123-174: M92A100W I1. Unpublished study prepared by Hazleton W i sconsin, Inc. 117 p.

93

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MRID CITATION



### ____________________________________________________
42661801 Kleiner, A. (1992) CL 92,100 (ter bufos/15G): Residues of Total CL 92,100-Related Com pounds in Dual Purpose Sorghum (KI; TX, 1991): Lab Project Num b er: C-3851. Unpublished study prepared by Am erican Cyanam id Co. 52 p.

43147501 Cortes, D.; Thom son, M. (1994) Product Identity and Discussion of Form ation of Im purities for COUNTER Technical: Addendum : Lab Project Num b er: CHDV/VOL/29/REPORT/2. Unpublis hed study prepared by Am erican Cyanam id Co. 44 p.

43147502 Thom son, M.; W ilson, L. (1994) Prelim inary Analysis, Certification of Lim its, and Analytical Methods for Enforcem ent for COUNTER Technical: (Addendum ): Lab Project Num b er: APBR/308: AP BR/307. Unpublished study prepared by Am erican Cyanam id Co. 95 p.

43147503 Raham a n, R. (1994) Physical and Chem ical Characteristics for COUNTER Technical: Addendum : Lab Project Num b er: CHDV/VOL/29/REPORT/3. Unpublished study prepared by Am erican Cyanam id Co. 4 p.

43237800 Am erican Cyanam id Co. (1994) Subm ission of residue data in support of registration standard f o r terbuf os. Transm ittal of 2 studies.

43237801 Cheng, T.; Zulalian, J. (1994) Terbufos (CL 92,100): Metabolic Fate of Carbon-14 CL 92,100 Derived Residues in Ti ssues and Milk of Lactating Goats: Addendum : Lab Project Num b er: HW I/6123/174: 6123/174. Unpublished study prepared by Hazelton W i sconsin, Inc. 64 p.

43237802 Higham
, J.; Fisher, R. (1988) CL 92100 (terbufos/15G): Residues of Total CL 92,100-Related Com pounds in Sweet Corn Following Banded and Post Applications in New York, W i sconsin, and Florida: Lab Project Num b er: C/3093: C/3096: C/3109. Unpublished study prepared by Am erican Cyanam id Co. 28 p.

43649401 W r ubel, J. (1995) Sum m a ry of Previously Subm itted Terbufos Data in Partial Fulf illm ent of the Requirem e nts f o r Residue Com m odity Storage Stability Data. Unpublished study prepared by Am erican Cyanam id Co. 11 p.

94

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### ____________________________________________________
43649402 Schroeder, R. (1989) A Two-Generation (Two-Litters) Reproduction Study W ith AC 92,100 to Rats: Lab Project Num b ers: 86-3128: 971-87-132. Unpublished study prepared by Bio/dynam i cs, Inc. 1806 p.

44267901 York, C. (1996) Terbufos (CL 92,100): Total CL 92,100-Related Residues in Sugar Beets After Treatm e nt with Counter 15G System ic Insecticide Nem a ticide Applied Postem ergence: Lab Project Num ber: RES 95-039: RES 95-040: RES 95-045. Unpublished study prepared by Am erican Cyanam id Co. 422 p. {OPPTS 860.1500}.

44267902 Higham
, J.; Picard, G. (1996) Terbufos (CL 92,100): Validation of Method M-2457 for the Determ ination of Total CL 92,100-Related Residues in Sugar Beet Tops and Roots: Lab Project Num b er: RES 95-118: ABC 42332: CT94PT01. Unpublished study prepared by Am erican Cyanam id Co. and ABC Laboratories, Inc. 52 p. {OPPTS 860.1340}.

44381201 Khunachak, A. (1997) CL 92,100 (Counter System ic Insecticide Nem a ticide): Freezer Storage Stability of Residues of Terbufos (CL 92,100) and its Related Com pounds (CL 94,301 and CL 94,320) in Soil: (Final Report): Lab Project Num b er: RES 96-073.01: CT95PT01: 0107. Unpublished study prepared by Am erican Cyanam id Co. and ABC Labs, Inc. 60 p. {OPPTS 840.1100}

44450600 Am erican Cyanam id Co. (1997) Subm ission of Toxicology Data in Support of the Reregistration for Terbufos. Transm ittal of 1 Study.

44450601 Com p ton, D. (1997) A Prelim inary Ra nge-Finding Rat Derm al Toxicity Study with AC 92100 CR: Lab Project Num b er: 97-2518: 971-97-125. Unpublished study prepared by Huntingdon Life Sciences. 128 p. {OPPTS 870.3200}

44464601 Higham
, J. (1997) CL 92100: Freezer Storage Stability of Residues of Terbufos-Related Com pounds (CL 94301, CL 94320, and CL 94221) in Sugar Beet Tops and Roots: Lab Project Num b er: RES 97-017: CT94PT02: 0107. Unpublished study prepared by ABC Laboratories, Inc. and Am erican Cyanam id Co. 52 p. {OPPTS 860.1380}

95

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### ____________________________________________________
44520501 Kelly, C. (1998) A Four-W eek Rat Derm al Toxicity Study with AC 92100 15G: Lab Project Num b er: 96-2487: 971-96-149. Unpublished study prepared by Huntingdon Life Sciences. 547 p. {OPPTS 870.3200}

44629302 Khunachak, A.; Kleiner, A.; Gross, J. (1998) Crop Residue Studies: Total Terbufos-Related Residues in Bananas After Treatm e nt with Counter System ic Insecticide-Nem a ticide: Lab Project Num b er: C-2789: C-3136: RES97-062. Unpublished study prepared by Am erican Agricultural Services, Inc. and Centre Analytical Laboratories, Inc. 385 p. {OPPTS 860.1340, 860.1500}

44629303 York, C.; Fletcher, P. (1998) Crop Residue Studies: Total Terbufos-Related Residues in Corn Grain After Treatm e nt with Counter System ic Insecticide-Nem a ticide Applied Post-Em e rgent or at Cultivation: Lab Project Num b er: RES95-058: RES95-059: RES96-021. Unpublished study prepared by Heartland Technologies, Inc. and ABC Laboratories, Inc. 430 p. {OPPTS 860.1500}

44672003 Mandella, R. (1998) An Acute Neurotoxicity Study with AC 92100 in the Rat Via Oral Gavage Adm i nistration: Lab Project Num b er: 98-4525: 97-4517: 971-98-140. Unpublished study prepared by Huntingdon Life Sciences. 763 p. {OPPTS 870.6200}

44672004 Kloppel, H. (1993) Degradation of (Carbon 14)-Terbufos in W a ter/Sedim e nt System s: Lab Project Num b er: CYA- 013/7-19. Unpublished study prepared by Fraunhofer-Institut fuer Um weltchem i e und Okotoxikologie. 57 p.

44690501 Com p ton, D. (1998) A Four-W eek Rat Derm al Toxicity Study with AC 92100 CR: Lab Project Num b er: CY216: 96-2494: 97-2518. Unpublished study prepared by Huntingdon Life Sciences. 253 p. {OPPTS 870.3200}

44793301 Higham
, J.; W a lls, C.; Sweeney, R. et al. (1999) Occupational Exposure and Risk Assessm ent for Loaders and Applicators Handling Terbufos Products and Supporting W o rker Exposure Studies: Lab Project Num b er: CY-24: 9902: EXA-99-004. Unpublished study prepared by ABC Laboratories, Inc. and Novigen Sciences. 607 p. {OPPTS 875.1000, 875.1100, 875.1300}

96

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### ____________________________________________________
44834301 Barraj, L.; Kidwell, J. (1999) Sensitivity Analysis Considering the Acute Dietary Exposure Estim ates in the Terbufos Risk Assessm ent: Lab Project Num b er: 99-01. Unpublished study prepared by Novigen Sciences, Inc. 254 p.

44842302 Mandella, R. (1999) 13-W eek Dietary Neurotoxicity Study with AC 92100 in the Rat: Lab Project Num b er: 98-4521: 971-98-102. Unpublished study prepared by Huntingdon Life Sciences. 734 p. {OPPTS 870.6200}

44862501 Martin, C.; Heim , D. (1999) (Carbon-14)-Terbufos (AC92100) and its Sulfoxide(AC94301) and Sulfone(AC94320) Metabolites: Hydrolysis in Sterile pH 5,7, and 9 Buffers: Lab Project Num b er: ENV97-017: ENV 97-017.01. Unpublished study prepared by ABC Labs., Inc. 388 p. {OPPTS 835.2120}

44862502 Martin, C.; Xia, C. (1999) (Carbon-14)-Terbufos (AC92100) and its Sulfoxide(AC94301) and Sulfone(AC94320) Metabolites: Degradation in Natural Pond W a ter: Lab Project Num b er: ENV-97-018. Unpublished study prepared by ABC Labs., Inc. 133 p. {OPPTS 835.2120, 835.4300}

97

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### ____________________________________________________
Studies Without MRID Numbers

Austin, 1981. Land Resources Regions and Major Land Resource Areas of the United States. USDA Handbook 296, revised 1981. W a shington, D.C. (Soil Conservation Service)

Barrett, M.R., Decem ber 3, 1997. Mem o randum from Joe Merenda to Larry Dorsey of the Science Advisory Panel. U.S. EPA/OPP/EFED.

Blondell JM, Taub SR. 1999. Poisoning incidence per 1000 applications am ong handlers of agricultural insecticides in California and acute derm al toxicity. Pesticides, People and Nature 1:15-24.

DeLuca, T., Larson, J., Torm a, L. and G. Algard. 1989. A Survey of Groundwater Contam ination by Pesticides in Montana, Montana Departm e nt of Agriculture, Technical Report 89-1, August 1989.

Detroy, M. 1985. Iowa Ground-W a ter-Quality Monitoring Program , U.S. Geological Survey, Open File Report 84-815, Decem ber 1985.

Detroy, M., Hunt, P., and M. Holub. 1988. Ground-W a ter-Quality Monitoring in Iowa: Nitrate and Pesticides in Shallow Aquifers, U.S. Geological Survey, W a ter Resources Investigations Report 88-4123.

Exner, M. and Roy Spalding. 1990. Occurrence of Pesticides and Nitrate in Nebraska' s Ground W a ter, University of Nebraska, Institute of Agriculture and Natural Resources.

Felsot, A., L. W e i, and J. W ilson. 1982. Environm ental chem odynam i c studies with terbufos (Counter TM ) insecticide in soil under laboratory and field conditions. Journal of environm ental science and health. Vol. B17(6), pp. 649-673.

Felsot, A., W .N. Bruce, and K.S. Steffey. 1987. Degradation of terbufos (Counter TM ) soil insecticide in corn fields under conservation tillage practices. Bulletin of Environm ental Contam ination and Toxicology Vol. 38:369-376.

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### ____________________________________________________ Hirsch, R.M. Alley, W

. M., and W ilbur, W

. B. 1988. Concepts of National W a ter Quality Assessm ent Program

. USGS Circular 1021.

Indiana Departm e nt of Environm ental Managem e nt. 1988. Assessm ent of Nonpoint Source Pollution of Ground W a ter in Indiana, July 1988.

Kelley, R.. 1985. Synthetic Organic Com pound Sam p ling Survey of Public W a ter Supplies, Iowa Departm e nt of Natural Resources, Des Moines, IA, April 1985.

Kelley, R. and W nuk, M. 1986. Little Sioux River Synthetic Organic Com pound Municipal W e ll Sam p ling Survey, Iowa Departm e nt of Natural Resources, Des Moines, IA, March 1986.

Kelley, R. 1986. 1986 Little Sioux River Pesticide Monitoring Report, Iowa Departm e nt of Natural Resources, Des Moines, IA, March 1988.

Kelley, R. 1986. University of Iowa, Hygienic Laboratory, personal

com m unication.

Klaseus, T., Buzicky, G. and E. Schneider. 1988. Pesticides and Ground W a ter: Surveys of Selected Minnesota W e lls, Minnesota Departm e nt of Health and Minnesota Departm e nt of Agriculture, February 1988.

Klaseus, T. and Hines, J. 1989. Pesticides and Ground W a ter: Surveys of Selected Minnesota W e lls, Minnesota Departm e nt of Health, August 1989.

Kleinbaum , D.G., L.L. Kupper, and H. Morgenstern. 1982. Epidem iological Research. Van Nostrand Reinhold.

Knapton, R.W ., and P. Mineau. 1995. Effects of granular form ulations of terbufos and fonofos applied to cornfields on m o rtality and reproductive success in songbirds. Ecotoxicology 4:138-153.

Lane, L. 1987. Mississippi Pesticide Hazard Assessm ent Project: Annual Progress Report No. 15, Mississippi State University, May 1987.

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### ____________________________________________________ Mayer, F.L. and Ellersieck, M.R. 1986. Manual of acute toxicity: interpretation and data base for 4510 chem icals and 66 species of freshwater anim als. USFW S Resource publ. 160.

Mesko, T. and Carlson, G. 1988. Occurrence of Pesticides, Nitrates, Organic Com pounds, and Trace Elem ents in Ground W a ter and Stream s, Southeastern Missouri, 1986-87, U.S. Geological Survey Open-File Report 88-495.

Rhode Island Departm e nt of Environm ental Managem e nt. 1990. Rhode Island Private W e ll Survey Final Report.

Sievers, D. and Fulhage, C. 1991. Quality of Rural W e ll W a ter North Missouri and Quality of Missouri' s Agricultural Groundwater Region II Sam p ling, University of Missouri, June 1991.

South Dakota Departm e nt of Environm ent and Natural Resources. 1993. 1992 Pesticide and Nitrogen Sam p ling Program and Five Year Sum M ., February 1993.

USEPA. 1992. Pesticides in Ground W a ter Database - A Com p ilation of Monitoring Studies: 1971 - 1991. Office of Prevention, Pesticides, and Toxic Substances. EPA 734-12-92-001. Septem ber 1992.

USEPA Office of W a ter. February 1996, Drinking W a ter Regulations and Health Advisories, EPA 822-R-96-001 United States Environm ental Protection Agency, Guidelines for Exposure Assessm ent; Federal Register Volum e 57, Num b er 104 (Friday May 29, 1992).

USEPA, Draft Standard Operating Proce dures (SOPs) For Residential Exposure Assessm ent (Decem ber 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 Assessm ent; (3/4/99) Chem ical ID No. 105001, Case 0109, DP Barcode D253850, From W illiam Hazel (OPP/HED/RRB-1) to Pam e la Noyes and Robert McNally (OPP/SRRD).

Various Correspondence From Am erican Cyanam id 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 W r ubel, Product Registrations Manager, U.S. Plant Regulatory Affairs.

Occupational And Residential Exposure Assessm ent And Recom m e ndations For The Reregistration Eligibility Docum e nt For Terbufos; (May 18, 1995) Chem ical ID No. 105001, Case 0109, DP Barcode D192404, From Alan P. Nielsen (OPP/HED/OREB) to Karen W h itby (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 W illiam Hazel (OPP/HED/RRB-1).

Use and Usage Inform ation; (7/15/99) sent by em ail by John W r ubel (Product Review Manager, Am erican Cyanam id) 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) com p leted by Dhol Herzi (EPA/OPP/BEAD).

Final Usage Analysis For Terbufos RED; (2/8/99) From Donald Atwood and Kathy Davis (OPP/BEAD) to Pam e la Noyes (OPP/SRRD).

Occupational Exposure and Risk Assessm ent For Loaders and Applicators Handling Terbufos Products and Supporti ng W o rker Exposure Studies; (3/26/99) Authored by Joseph Higham
, Richard Honeycutt, D. Larry Merricks, Rose A. Sweeney, Cassi L. W a lls, and Susan H Youngren; Com p leted by ABC Laboratories of Colum b ia MO, HERAC of Greensboro NC, Agrisearch of Frederick MD, Novigen Sciences of W a shington DC, and Am erican Cyanam id of Princeton NJ.; Project ID #s include: Exhibit 1 of EPA MRID 447933-01,

101

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CITATION



### ____________________________________________________ Terbufos 99-02, EXA 99-004, EXA 99-006, and RES 99-003, Sponsored by Am erican Cyanam id.

Exposure of Farm workers To Terbufos (CL 92100) W h ile Loading COUNTER 15G System ic Insecticide-Nem a ticide W ith A Lock-N-Load Closed Handling System And Applying COUNTER 15G To Corn At Planting Tim e ; (3/26/99) Authored by Joseph Higham ; Com p leted by ABC Laboratories of Colum b ia MO, Agrisearch of Frederick MD, and Am eri can Cyanam id 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 Am erican Cyanam id.

Exposure of Farm workers To Terbufos (CL 92100) W h ile Loading COUNTER CR System ic Insecticide-Nem a ticide From A Bag And Applying COUNTER CR To Corn At Planting Tim e ; (3/26/99) Authored by Joseph Higham ; Com p leted by ABC Laboratories of Colum bia MO, HE RAC of Greensboro NC, and Am erican Cyanam id 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 Am erican Cyanam id.

CL92100 (terbufos): Validation of GC/FPD Determ inative Methods M3153, M3154, M3155, and M 3156 For The Determ ination of CL 92100 Residues In, Respectively, W hole Body Dosim e ters, Aerosol OT Handwash and Glove W a sh Solutions, Air Sam p ling Tubes and Face/Neck W i pes; (3/26/99) Authored by Joseph Higham
, Jill Cooper, and Rose Sweeney; Com p leted by ABC Laboratories of Colum b ia MO, and Am erican Cyanam id of Princeton NJ.; Project ID #s include: Exhibit 4 of EPA MRID 447933-01, ABC Report 44703, and RES 99­ 003, Sponsored by Am erican Cyanam id.

Terbufos Updated Risk Assessm ent USDA Com m e nts; (June 25, 1999) Forwarded by Therese Murtaugh of USDA.

Terbufos (AC 92100) - Response To Regist rant’s Rebuttal Regarding Reference Dose; Dust Generation/Characterization Studies; (July 5, 1996) Authored by Alan C. Levy (OPP/HED/Tox-II) to W illiam Hazel and Christina Swartz (OPP/HED/RCAB). Provides cursory re view of study entitled Counter CR and Counter 15G, Dust Generation and Charact erization by V Arendt (com pleted on 2/16/96, ID F-1356, subm itted on 5/23/96).

102

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CITATION



### ____________________________________________________ Exposure of Farm workers To Terbufos (CL 92100) W h ile Loading COUNTER 15G System ic Insecticide-Nem a ticide W ith A Lock-N-Load Closed Handling System And Applying COUNTER 15G To Corn At Planting Tim e ; (3/26/99) Authored by Joseph Higham ; Com p leted by ABC Laboratories of Colum b ia MO, Agrisearch of Frederick MD, and Am eri can Cyanam id 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 Am erican Cyanam id.

Exposure of Farm workers To Terbufos (CL 92100) W h ile Loading COUNTER CR System ic Insecticide-Nem a ticide From A Bag And Applying COUNTER CR To Corn At Planting Tim e ; (3/26/99) Authored by Joseph Higham ; Com p leted by ABC Laboratories of Colum bia MO, HE RAC of Greensboro NC, and Am erican Cyanam id 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 Am erican Cyanam id.

CL92100 (terbufos): Validation of GC/FPD Determ inative Methods M3153, M3154, M3155, and M 3156 For The Determ ination of CL 92100 Residues In, Respectively, W hole Body Dosim e ters, Aerosol OT Handwash and Glove W a sh Solutions, Air Sam p ling Tubes and Face/Neck W i pes; (3/26/99) Authored by Joseph Higham
, Jill Cooper, and Rose Sweeney; Com p leted by ABC Laboratories of Colum b ia MO, and Am erican Cyanam id of Princeton NJ.; Project ID #s include: Exhibit 4 of EPA MRID 447933-01, ABC Report 44703, and RES 99­ 003, Sponsored by Am erican Cyanam id.

Occupational Exposure and Risk Assessm ent For Loaders and Applicators Handling Terbufos Products and Supporti ng W o rker Exposure Studies; (3/26/99) Authored by Joseph Higham
, Richard Honeycutt, D. Larry Merricks, Rose A. Sweeney, Cassi L. W a lls, and Susan H Youngren; Com p leted by ABC Laboratories of Colum b ia MO, HERAC of Greensboro NC, Agrisearch of Frederick MD, Novigen Sciences of W a shington DC, and Am erican Cyanam id 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 Am erican Cyanam id

103Appendix E. GENERIC DATA CALL-IN

See table in docket for a list of generic data requirem e nts. Note that a com p lete Data Call-In (DCI), with all pertinent instructions, is being sent to registrants under separate cover.

104Appendix F. PRODUCT SPECIFIC DATA CALL-IN

See table in docket for a list of product-specific data requirem e nts. Note that a com p lete Data Call-In (DCI), with all pertinent instructions, is being sent to registrants under separate

cover.

105Appendix G. EPA’S BATCHING OF TERBUFOS PRODUCTS FOR MEETING ACUTE TOXICITY DATA REQUIREMENTS FOR REREGISTRATION

In an ef f o rt to reduce the tim e, resources and num ber of anim als needed to f u lf ill the acute toxicity data requirem e nts for reregistration of products containing terbufos as the active ingredient, the Agency has batched products which can be considered sim ilar for purposes of acute toxicity. Factors considered in the sorting process include each product' s active and inert ingredients (identity, percent com position and bi ological activity), type of form ulation (e.g.,

em ulsifiable concentrate, aerosol, wettable pow der, granular, etc.), and labeling (e.g., signal word, use classification, precautionary labeling, etc. ). Note that the Agency is not describing batched products as "substantially sim ilar" since som e products within a batch m a y not be considered chem ically sim ilar or have identical use patterns.

Using available inform ation, batching has been accom p lished by the process described in the preceding paragraph. Notwithstanding the batching process, the Agency reserves the right to require, at any tim e, acute toxicity data for an individual product should the need arise.

Registrants of products within a batch m a y choose to cooperatively generate, subm it 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

som e 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 m u st use one of the products within the batch as the test

m a terial. If a registrant chooses to rely upon previously subm itted acute toxicity data, he/she

m a y do so provided that the data base is com p lete and valid by today' s standards (see acceptance criteria attached), the f o rm ulation tested is considered by EPA to be sim ilar f o r acute toxicity, and the form ulation has not been significantly altered since subm ission and acceptance of the acute toxicity data. Regardless of whether new data is generated or existing data is referenced, registrants m u st clearly identif y the test m a teri al by EPA Registration Num b er. If m o re than one confidential statem ent of form ula (CSF) exists for a product, the registrant m u st indicate the form ulation actually tested by identifying the corresponding CSF.

In deciding how to m eet the product specific data requirem e nts, registrants m u st follow the directions given in the Data Call-In Notice and its attachm e nts appended to the RED. The DCI Notice contains two response form s which are to be com p leted and subm itted to the Agency within 90 days of receipt. The first form , "Data Call-In Response," asks whether the registrant will m eet the data requirem e nts for each product. The second form , "Requirem e nts 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 m u st decide whether he/she will provide the data or depend on som e one else to do so. If a registrant supplies the data to support a batch of products, he/she m u st select one of the following options: Developing Data (Option 1), Subm itting an Exis ting Study (Option 4), Upgrading an Existing Study (Option 5) or Citing an Existing Study (Op tion 6). If a registrant depends on another' s data, he/she m u st choose am ong: Cost Sharing (O ption 2), Offers to Cost Share (Option 3) or

106Citing 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 form ulation.

• T he products in Batch 2 m a y be supported by citing/subm itting the acute data from Batch 1.

• T he products in Batch 3 m a y be supported by citing/subm itting the acute data from Batch 1.

NOTE: The technical acute toxicity values included in this docum ent are for inform ational purposes only. The data supporting these values m a y or m a y not m eet the current acceptance criteria.

Batch EPA Reg. No. % Active Ingredient Form ulation Type
1 241-241 85.0 Solid

Batch EPA Reg. No. % Active Ingredient Form ulation Type
2 241-314 20.0 Solid

Batch EPA Reg. No. % Active Ingredient Form ulation Type 3 241-238 15.0 Solid

107Appendix H. LIST OF REGISTRANTS SENT THIS DATA CALL-IN

1) BASF Corporation

108Appendix I. LIST OF AVAILABLE RELATED DOCUMENTS AND ELECTRONICALLY AVAILABLE FORMS



### Pesticide Registration Forms are availabl e at the follow i ng EPA internet site:

http://www.epa.gov/opprd001/form s/.

Pesticide Registration Form s (These form s are in PDF form at and require the Acrobat reader)

Instructions

1. Print out and com p lete the form s. (Note: Form num bers that are bolded can be filled out on your com puter then printed.)

2. The com p leted form (s) should be subm itted in hardcopy in accord with the existing policy.

3. Mail the form s, along with any additional docum ents necessary to com p ly with EPA regulations covering your request, to the address below for the Docum e nt Processing Desk.

DO NOT fax or e-m a il any form containing ' C onfidential Business Inform ation' or ' S ensitive Inform ation.'

If you have any problem s accessing these form s, please contact Nicole W illiam s at (703) 308-5551 or by e-m a il at william s .nicole@epam a il.epa.gov.

The following Agency Pesticide Registration Form s are currently available via the internet: at the f o llowing locations:

8570-1 Application for Pesticide Registration/Amendment http://www.epa.gov/opprd001/forms/8570-1.pdf.

8570-4 C onfidential Statement of Formula http://www.epa.gov/opprd001/forms/8570-4.pdf.

8570-5 N otice 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 Regis t ration of a P e s ticide To M eet a S p ecial 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.

1098570-28 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 Phy s ical/Chemical Properties (in PR Notice 98-1) http://www.epa.gov/opppmsd1/PR_Notices/pr98-1.pdf.

8570-37 Self-Certification Statement for the Phy s ical/Chem i cal 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 assem b led an online registration kit which contains the following pertinent form s and inform ation needed to register a pesticide product with the U.S. Environm ental Protection Agency' s Office of Pesticide Program s (OPP):

1. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal Food, Drug and Cosm etic Act (FFDCA) as Am ended by the Food Quality Protection Act (FQPA) of 1996.

2. Pesticide Registration (PR) Notices

a. 83-3 Label Im provem e nt Program --Storage and Disposal Statem ents b. 84-1 Clarification of Label Im provem e nt Program

c. 86-5 Standard Form at for Data Subm itted under FIFRA d. 87-1 Label Im provem e nt Program for Pesticides Applied through Irrigation System s (Chem i gation)

e. 87-6 Inert Ingredients in Pesticide Products Policy Statem ent f. 90-1 Inert Ingredients in Pesticide Products; Revised Policy Statem ent g. 95-2 Notifications, Non-notifications , and Minor Form ulation Am endm ents h. 98-1 Self Certification of Product Chem istry Data with Attachm e nts (This docum ent is in PDF form at and requires the Acrobat reader.)

110Other PR Notices can be found at http://www.epa.gov/opppm sd1/PR_Notices.

3. Pesticide Product Registration Application Form s (These form s are in PDF form at and will require the Acrobat reader.)

a. EPA Form No. 8570-1, Application for Pesticide Registration/Am endm ent b. EPA Form No. 8570-4, Confidential Statem ent of Form ula

c. EPA Form No. 8570-27, Form ulator' s Exem ption Statem ent d. EPA Form No. 8570-34, Certification with Respect to Citations of Data

e. EPA Form No. 8570-35, Data Matrix

4. General Pesticide Inform ation (Som e of these form s are in PDF form at and will require the Acrobat reader.)

a. Registration Division Personnel Contact List B. Biopesticides and Pollution Prevention Division (BPPD) Contacts C. Antim icrobials Division Organiza tional Structure/Contact List d. 53 F.R. 15952, Pesticide Registration Procedures; Pesticide Data Requirem e nts (PDF form at)

e. 40 CFR Part 156, Labeling Requirem e nts for Pesticides and Devices (PDF form at) f.. 40 CFR Part 158, Data Requirem e nts for Registration (PDF form at)
g.. 50 F.R. 48833, Disclosure of Reviews of Pesticide Data (Novem b er 27, 1985)

Before subm itting your application for registration, you m a y wish to consult som e additional sources of inform ation. These include:

1. The Office of Pesticide Program s' W e b Site

2. The booklet "General Inform ation on Applying for Registration of Pesticides in the United States", PB92-221811, available through the National Technical Inform ation Service (NTIS) at the following address:

National Technical Inform ation Service (NTIS) 5285 Port Royal Road Springfield, VA 22161

The telephone num ber 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 Of f i ce of Pesticide Program s. W e anticipate that this publication will becom e available during the Fall of 1998.

3. The National Pesticide Inf o rm ation Retrieval System (NPIRS) of Purdue University' s Center for Environm ental and Regulatory Inform ation System s. This

111service does charge a fee for subscriptions and custom searches. You can contact NPIRS by telephone at (765) 494-6614 or through their W e b site.

4. The National Pesticide Telecom m unications Network (NPTN) can provide inform ation on active ingredients, uses, toxicology, and chem istry of pesticides. You can contact NPTN by telephone at (800) 858-7378 or through their W e b site: ace.orst.edu/info/nptn.

The Agency will return a notice of receipt of an application for registration or

am ended registration, experim e ntal use perm it, or am endm ent to a petition if the applicant or petitioner encloses with his subm ission a stam ped, self -addressed postcard. The postcard m u st contain the following entries to be com p leted by OPP:

Date of receipt EPA identifying num ber Product Manager assignm ent

Other identifying inform ation m a y be included by the applicant to link the acknowledgm ent of receipt to the specific application subm itted. EPA will stam p the date of receipt and provide the EPA identifying File Sym bol or petition num ber for the new subm ission. The identifying num ber should be used whenever you contact the Agency concerning an application for registration, experim e ntal use perm it, or tolerance petition.

To assist us in ensuring that all data you have subm itted for the chem ical are properly coded and assigned to your com p any, please include a list of all synonym s,
com m on and trade nam e s, com p any experim e ntal codes, and other nam e s which identif y the chem ical (including "blind" codes used when a sam p le was subm itted for testing by com m e rcial or academ ic facilities). Please provide a CAS num ber if one has been assigned.



### Documents Associated w i th this RED

The following docum ents are part of the Adm i nistrative Record for this RED docum ent and

m a y included in the EPA' s Office of Pesticide Program s Public Docket. Copies of these docum ents are not available electronically, but m a y be obtained by contacting the person listed on the respective Chem ical Status Sheet.

1. Health and Environm ental Effects Science Chapters. 2. Detailed Label Usage Inform ation System (LUIS) Report.

112