![](media/image1.png){width="1.1in"
height="1.0638888888888889in"}**UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY**

WASHINGTON, D.C. 20460

# 

# 

# 

# MEMORANDUM

Date: February 28, 2006

Subject: TCMTB. Summary of Analytical Chemistry and Residue Data for the

Reregistration Eligibility Decision (RED) Document.

DP Barcode: D322617 PC Code: 035603

40 CFR §: 180.288 Chemical Class: Benzothiazole

From: Samuel Ary, Chemist

Reregistration Branch II

Health Effects Division (7509C)

Through: P. Yvonne Barnes, Chemist

Reregistration Branch II

Health Effects Division (7509C)

William Hazel, Branch Chief

Reregistration Branch II

Health Effects Division (7509C)

To: Deborah Smegal, Risk Assessor

Reregistration Branch I

Health Effects Division (7509C)

Kathryn Avivah Jakob, Chemical Review Manager

Regulatory Management Branch II

Antimicrobial Division (7510C)

**Executive Summary**

As an antimicrobial pesticide, TCMTB \[(2-benzothiazolylthio)methyl
thiocyanate\] is used largely as a wood preservative. It is also used as
a microbiocide/microbiostat and bacteriocide/bacteriostat in industrial
processes and water systems, as well as in industrial materials, as a
preservative. As an agricultural pesticide, TCMTB is a fungicide used as
a seed treatment on barley, corn, cotton, oat, rice, safflower, sorghum,
sugar beet, and wheat.

The reregistration of TCMTB is being supported by Bayer CropScience
(Bayer) and Wilbur-Ellis Company (Wilbur-Ellis). TCMTB food/feed end-use
products are marketed in the United States under the trade names
Busan^®^, Cotguard^®^, Nusan^®^, and Nu-Flow^®^. The Bayer and
Wilbur-Ellis TCMTB formulations registered for food/feed uses include
emulsifiable concentrate (EC) and soluble concentrate (SC). For
food/feed uses, Bayer is supporting TCMTB use on cotton only, while
Wilbur-Ellis is supporting uses on barley, cotton, oat, rice, wheat,
safflower, and sugar beet. The technical registrant of TCMTB, Buckman
Laboratories, Inc. (Buckman) has requested cancellation of all food/feed
uses. Therefore, use on corn and sorghum is no longer being supported.
Bayer and Wilbur-Ellis will be responsible for providing the Agency with
the appropriate data needed to maintain the supported uses on their
product labels.

Tolerances are established for residues of the fungicide
2-(thiocyanomethylthio)benzothiazole in/on barley (grain and straw),
sugar beets (roots and tops), corn (forage, grain, and stover), cotton
(forage and undelinted seed), oats (forage, grain, hay, and straw), rice
(grain and straw), safflower (seed), sorghum (forage, grain, and
stover), and wheat (forage, grain, hay, and straw) at 40 CFR §180.288.
The permanent tolerances for residues in plant commodities are
established at the limit of quantitation (LOQ) of 0.1 ppm (N). The "N"
designation, denoting "negligible" residues must be deleted from 40 CFR
§180.288.

The reregistration requirements for plant metabolism have not been
fulfilled. Data have been submitted depicting the uptake of TCMTB in
corn, cotton, safflower, and wheat and were found to be inadequate due
to lack of identification and/or characterization of parent and/or
metabolites. Additional metabolism studies conducted with tomatoes and
melons have been submitted and briefly reviewed; however, translation to
the currently registered crops is not adequate for reregistration
purposes. Confirmatory metabolism data should be submitted depicting the
nature of residues in wheat, cotton, and sugar beets. Adequate
identification and/or characterization of parent and/or metabolites
should be conducted as required by OPPTS 860 Series Guidelines. The Risk
Assessment Review Committee (RARC) met and determined that the interim
residue of concern for tolerance expression and risk assessment is TCMTB
in/on plants (P. Deschamp, Report of the RARC, 1/11/2006). This is a
preliminary decision and the additional confirmatory plant metabolism
data should be submitted in a timely manner.

No livestock metabolism studies have been submitted for review.
Livestock metabolism studies may be required if the requested plant
metabolism studies show uptake of residues. If livestock metabolism
studies are required, the registrant must provide poultry and ruminant
metabolism studies following OPPTS 860 Series Guidelines.

A tolerance enforcement method is available for determining
thiobenzothiazole-containing residues in barley, corn, cotton, oat,
rice, safflower, sugar beet, and wheat. This method was originally
submitted with Pesticide Petition (PP) 0F0954 by Buckman. Residues are
converted to 2-chlorobenzothiazole, which is determined by a gas-liquid
chromatography (GLC) method using an electron capture detector (ECD).
The quantitation limit of the method has been determined at 0.10 ppm.
This method is listed as Method B in PAM Vol. II. The method is outdated
and uses toxic reagents; therefore, if an additional method that is
adequate for tolerance enforcement is available, it should be submitted
immediately for review.

Two data-collection methods are available for determining
thiocyanate-containing residues. The first method was originally
submitted with PP 0F0954 by Buckman for the determination of residues in
barley, corn, cottonseed, oat, rice, and wheat. The method is listed as
Method I in PAM Vol. II. The second method was originally submitted with
PP 5F1613 by Buckman for the determination of residues in safflower
seed, sorghum grain and foliage, and sugar beet and foliage. The method
is listed as Method A in PAM Vol. II. Residues are converted from
thiocyanate to cyanogen bromide; then the cyanogen bromide is treated
with pyridine-benzidine reagent to form an intensely colored dye. The
absorbance of the dye solution is determined at 532 nm. In a method
tryout (Method I), the Agency obtained recoveries of 90% and 110%
(duplicate samples) at the 0.10 ppm fortification level and 105% and
115% (duplicate samples) at the 0.20 ppm fortification level. The
quantitation limit of both methods has been determined at 0.10 ppm.

If the requested metabolism studies show additional residues are of
concern and the current enforcement method does not capture these
additional residues, development of a method capable of doing so will be
required.

The requirement of a tolerance enforcement method for livestock is put
on reserve pending the results from the requested plant metabolism
studies, and, if required, the livestock metabolism studies.

The FDA PESTDATA database dated 11/2001 (PAM Volume I, Appendix I)
indicates that TCMTB *per se* is completely recovered (\>80%) using
Multiresidue Methods Section 302 (Luke Method), but is only partially
recovered (50-80%) using 303 (Mills, Onley, Gaither Method) and 304
(Mills fatty food Method). If additional residues of concern are
determined from the requested metabolism studies, all additional
residues of concern for tolerance expression will need to be tested
through Multiresidue Methods.

Storage stability data for TCMTB in/on barley, cotton, oat, rice, wheat,
safflower, and sugar beet have not been submitted by the registrant. No
data were provided on how long samples from the submitted field trials
were stored prior to analysis; therefore, storage stability data for the
previously submitted field trials are required and should be submitted
immediately. Additionally, if field trials are required or additional
uses are requested, concurrent storage stability data will be required
under this guideline topic.

TCMTB is not intended for application to livestock and no livestock
feeding studies have been submitted. The grain crops, their byproducts
and forages, are livestock feed items. It is therefore necessary to
consider if TCMTB residues are transferred to meat, milk, poultry, and
eggs of livestock through ingestion of the residue bearing commodities.
It has been indicated in the foregoing considerations that the nature of
residue in plants has not been adequately described. In the absence of
such data, the residue level is unclear. If the requested residue data
show finite residues in the feed items, livestock feeding studies would
be essential to an evaluation of the transfer of residues to milk, meat,
poultry, and eggs. Therefore, no valid conclusions relative to 40 CFR
§180.6 (the necessity of tolerances in livestock commodities) can be
made in the absence of livestock feeding studies.

The available field trial data are not adequate according to current
OPPTS 860 Series Guidelines. The correct number of field trials, number
of samples collected, and locations of trials are all insufficient.
Additionally, no storage stability data was submitted with the field
trial studies and the application rates are unknown for the barley,
corn, oat, rice, and wheat studies. The method used for determining
residues in barley, corn, oat, rice, and wheat is the data-collection
method which only determines the thiocyanate ion (Method I or A in PAM
Vol. II). The method used for determining residues in cotton is the
tolerance enforcement method which determines
thiobenzothiazole-containing residues (Method B in PAM Vol. II). If the
requested metabolism studies show additional metabolites of concern are
expected, new field trials should be conducted using a method which is
capable of determining all residues of concern as determined by the
tolerance expression. Additionally, tolerances should be proposed in/on
barley hay and cotton gin byproducts as these are now considered
significant livestock feed items according to Table 1 of OPPTS 860.1000.
Field trial data are not available for sugar beets; therefore, magnitude
of residue data in sugar beets should be submitted following all OPPTS
860 Series Guidelines.

No processing studies have been submitted. Once the requested metabolism
studies have been submitted, reviewed, and the metabolites of concern
are determined, data should be submitted which show whether residues
concentrate in the byproducts of the registered raw agricultural
commodities.

No confined accumulation data in rotational crops are available;
however, soil persistence studies are available. The registrant should
provide confirmatory method data along with storage stability data in
order for the data to be considered scientifically adequate. Contingent
upon the adequacy of the storage stability and method data, soil
persistence is not likely to be a concern with respect to follow-up
crops. However, the method used is unknown and the exact compounds that
make up the residues found is unknown; therefore, this data requirement
is put on reserve awaiting submission of the requested data and pending
the results from the plant metabolism studies.

**Residue Chemistry Deficiencies and Regulatory Guidelines**

1.  Confirmatory metabolism data should be submitted depicting the
    nature of residues in wheat, cotton, and sugar beets.

2.  The available enforcement method (Method B in PAM Vol. II.) is
    outdated and uses toxic reagents; therefore, if an additional method
    that is adequate for tolerance enforcement is available, it should
    be submitted immediately for review.

3.  Storage stability data were not included with the original field
    trial data submissions; therefore, storage stability data for the
    previously submitted field trials are required and should be
    submitted immediately.

4.  Storage stability and method data were not provided with the
    original soil persistence studies summarized under OPPTS 860.1850 in
    this document. Storage stability and method data are required and
    should be submitted immediately.

5.  Application rates in lbs a.i./100 lbs seed for all the submitted
    field trial studies should be provided.

6.  Tolerances for barley hay and cotton gin byproducts should be
    proposed once the requested metabolism data are submitted and
    reviewed.

7.  Data should be submitted which show whether residues concentrate in
    the byproducts of the registered raw agricultural commodities.

8.  Magnitude of residue data in sugar beets following all OPPTS 860
    Series Guidelines should be submitted.

9.  Additionally, numerous OPPTS 860 Series Guidelines have been placed
    on reserve pending the requested plant metabolism data (see Table
    4).

**Background**

The TCMTB Phase 4 Review dated 3/11/1991 summarized the status of
available residue chemistry data for the reregistration of TCMTB. The
Phase 4 Review requested plant metabolism data on corn or wheat, cotton,
and sugar beet. Data requirements for livestock metabolism, residue
analytical methods, storage stability, and magnitude of the residue in
plants were put on reserve status pending the results from the plant
metabolism studies. This document presents an overall and up-to-date
Residue Chemistry Science Assessment with respect to the reregistration
of TCMTB. The PC Code and nomenclature of TCMTB are listed below in
Table 1 and the physicochemical properties are listed in Table 2. The
structure of TCMTB and metabolites/degradates of concern are presented
in Table 3.

  -----------------------------------------------------------------------
  **Table 1. TCMTB       
  Nomenclature.**        
  ---------------------- ------------------------------------------------
  Chemical structure     ![](media/image2.wmf)

  Common name            TCMTB or TCMB

  Molecular formula      C~9~H~6~N~2~S~3~

  IUPAC name             2-(thiocyanomethylthio)benzothiazole

  CAS name               (2-benzothiazolylthio)methyl thiocyanate

  CAS number             21564-17-0

  PC Code                035603

  Supported food/feed    barley, cotton, oat, rice, safflower, sugar
  site uses              beet, and wheat
  -----------------------------------------------------------------------

+------------------------+-------------------------+------------------+
| **Table 2.             |                         |                  |
| Physicochemical        |                         |                  |
| Properties of TCMTB**  |                         |                  |
+========================+=========================+==================+
| Parameter              | Value                   | Reference        |
+------------------------+-------------------------+------------------+
| Molecular weight       | 238.35 g/mol            | Merck Index      |
|                        |                         | 12^th^ Edition   |
+------------------------+-------------------------+------------------+
| Melting point/range    | Not applicable (NA) for | NA               |
|                        | liquids                 |                  |
+------------------------+-------------------------+------------------+
| Boiling point/range    | Decomposed at 191C at  | C. Jiang,        |
|                        | 741.9 mm Hg             | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+
| pH                     | 5.99 (1:100 dilution in | C. Jiang,        |
|                        | water)                  | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+
| Density                | 1.3761 g/cm^3^          | C. Jiang,        |
|                        |                         | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+
| Water solubility       | 45 mg/L                 | C. Jiang,        |
|                        |                         | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+
| Vapor pressure         | 1.45 x 10^-4^ mm Hg at  | C. Jiang,        |
|                        | 20C                    | D322899,         |
|                        |                         | 11/17/05         |
|                        | 1.72 x 10^-4^ mm Hg at  |                  |
|                        | 25C                    |                  |
+------------------------+-------------------------+------------------+
| Vapor pressure^1^      | 2.44 x 10^-10^ mm Hg at | C. Jiang,        |
|                        | 20C                    | D322899,         |
|                        |                         | 11/17/05         |
|                        | 4.04 x 10^-10^ mm Hg at |                  |
|                        | 25C                    |                  |
+------------------------+-------------------------+------------------+
| Dissociation constant, | NA                      | NA               |
| pK~a~                  |                         |                  |
+------------------------+-------------------------+------------------+
| Octanol/water          | log K~ow~ of 3.23 at    | C. Jiang,        |
| partition coefficient  | 20C                    | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+
| Viscosity              | 352.4 cSt               | C. Jiang,        |
|                        |                         | D322899,         |
|                        |                         | 11/17/05         |
+------------------------+-------------------------+------------------+

1\. Tests done with pure active ingredient (PAI).

+------------------------+--------+-----+-----+----------------------+
| **Table 3. Chemical    |        |     |     |                      |
| Names, Metabolism      |        |     |     |                      |
| Data, and Structures   |        |     |     |                      |
| of TCMTB and Its       |        |     |     |                      |
| Met                    |        |     |     |                      |
| abolites/Degradates.** |        |     |     |                      |
+========================+========+=====+=====+======================+
| Chemical Name          | Com    | P   |     | Structure            |
|                        | modity | erc |     |                      |
|                        |        | ent |     |                      |
|                        |        | TRR |     |                      |
|                        |        | ^1^ |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        |        | Ma  | Mi  |                      |
|                        |        | jor | nor |                      |
|                        |        | R   | R   |                      |
|                        |        | esi | esi |                      |
|                        |        | due | due |                      |
|                        |        | (\> | (\< |                      |
|                        |        | 10% | 10% |                      |
|                        |        | T   | T   |                      |
|                        |        | RR) | RR) |                      |
+------------------------+--------+-----+-----+----------------------+
| TCMTB                  | Melon  |     | ND  | !                    |
|                        | fruit  |     | ^2^ | [](media/image3.wmf) |
| \[2-ben                |        |     |     |                      |
| zothiazolylthio)methyl |        |     |     |                      |
| thiocyanate\]          |        |     |     |                      |
|                        |        |     |     |                      |
| CAS number: 21564-17-0 |        |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Melon  |     | 0   |                      |
|                        | plant  |     | .9% |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | fruit  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | plant  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | A      |     | 0   |                      |
|                        | erobic |     | .6% |                      |
|                        | soil   |     |     |                      |
|                        | (58    |     |     |                      |
|                        | D      |     |     |                      |
|                        | PT^3^) |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
| 2-BTSA                 | Melon  | 31  |     | !                    |
|                        | fruit  | .9% |     | [](media/image4.wmf) |
| \[2                    |        |     |     |                      |
| -benzothiazolesulfonic |        |     |     |                      |
| acid\]                 |        |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Melon  | 14  |     |                      |
|                        | plant  | .0% |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato | 61  |     |                      |
|                        | fruit  | .7% |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato | 32  |     |                      |
|                        | plant  | .6% |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | A      | 70  |     |                      |
|                        | erobic | .8% |     |                      |
|                        | soil   |     |     |                      |
|                        | (58    |     |     |                      |
|                        | DPT)   |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
| OH-2-BTSA^4,5^         | Melon  |     | 8   | !                    |
|                        | fruit  |     | .4% | [](media/image5.wmf) |
| \[2-(hydroxyb          |        |     |     |                      |
| enzothiazolyl)sulfonic |        |     |     |                      |
| acid\]                 |        |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Melon  |     | 2   |                      |
|                        | plant  |     | .6% |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | 8   |                      |
|                        | fruit  |     | .5% |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato | 21  |     |                      |
|                        | plant  | .2% |     |                      |
+------------------------+--------+-----+-----+----------------------+
| 2-OH-BT                | Melon  |     | 1   | !                    |
|                        | fruit  |     | .3% | [](media/image6.wmf) |
| \[2-                   |        |     |     |                      |
| hydroxybenzothiazole\] |        |     |     |                      |
| or                     |        |     |     |                      |
|                        |        |     |     |                      |
| BTOL                   |        |     |     |                      |
|                        |        |     |     |                      |
| \[2-benzothiazolol\]   |        |     |     |                      |
|                        |        |     |     |                      |
| CAS number: 934-34-9   |        |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Melon  |     | 2   |                      |
|                        | plant  |     | .5% |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | fruit  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | plant  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | A      |     | 7   |                      |
|                        | erobic |     | .0% |                      |
|                        | soil   |     |     |                      |
|                        | (21    |     |     |                      |
|                        | DPT)   |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
| 2-MBT or 2-SH-BT       | Melon  |     | 0   | !                    |
|                        | fruit  |     | .7% | [](media/image7.wmf) |
| \[2-m                  |        |     |     |                      |
| ercaptobenzothiazole\] |        |     |     |                      |
|                        |        |     |     |                      |
| CAS number: 149-30-4   |        |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Melon  |     | 0   |                      |
|                        | plant  |     | .1% |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | fruit  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Tomato |     | ND  |                      |
|                        | plant  |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | Cotton |     | ND  |                      |
|                        | forage |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | A      | 30  |     |                      |
|                        | erobic | .3% |     |                      |
|                        | soil   |     |     |                      |
|                        | (1.5   |     |     |                      |
|                        | DPT)   |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
|                        | A      |     | 0.  |                      |
|                        | erobic |     | 3-0 |                      |
|                        | soil   |     | .4% |                      |
|                        | (14-21 |     |     |                      |
|                        | DPT)   |     |     |                      |
+------------------------+--------+-----+-----+----------------------+
| 2,2'-DTBB or DBB       | A      |     | 6   | !                    |
|                        | erobic |     | .7% | [](media/image8.wmf) |
| \[2,2'-di              | soil   |     |     |                      |
| thiobis(benzothiazole) | (m     |     |     |                      |
|                        | aximum |     |     |                      |
| CAS number: 120-78-5   | at 1   |     |     |                      |
|                        | DPT)   |     |     |                      |
+------------------------+--------+-----+-----+----------------------+

1\. TRR = Total radioactive residue.

2\. ND = Not detected.

3\. DPT = Days post-treatment.

4\. Two isomers make up 2-(hydroxybenzothiazolyl)sulfonic acid. The
exact position of the hydroxyl group was not determined. The numbers
presented in the table are the summation of the two isomers. The
following is the breakdown of TRR for each isomer (in parenthesis)
following each individual commodity: melon fruit: 8.4% (1.1% and 7.3%);
melon plant: 2.6% (1.4% and 1.2%); tomato fruit: 8.5% (6.9% and 1.6%);
and tomato plant: 21.2% (6.7% and 14.5%).

**Summary of Science Findings**

Number range CHAPTERA tabular summary of the residue chemistry science
assessments for reregistration of TCMTB is presented below in Table 4.
The conclusions listed in Table 4 regarding the reregistration
eligibility of TCMTB food/feed uses are based on the use patterns being
supported by Bayer and Wilbur-Ellis. When end-use product data-call-ins
(DCIs) are developed (e.g., at issuance of the RED), the Registration
Division (RD) should require that all end-use product labels (e.g., MAI
labels, special local needs (SLNs), and products subject to the generic
data exemption) be amended such that they are consistent with labels
registered to Bayer and Wilbur-Ellis.

+---------------------------+------------+----------+-----------------+
| Number range              |            |          |                 |
| CHAPTER**Table 4. Residue |            |          |                 |
| Chemistry Science         |            |          |                 |
| Assessment for the        |            |          |                 |
| Reregistration of         |            |          |                 |
| TCMTB.**                  |            |          |                 |
+===========================+============+==========+=================+
| GLN Data Requirements     | Current    | Must     | References      |
|                           | T          | Ad       |                 |
|                           | olerances, | ditional |                 |
|                           | ppm \[40   | Data Be  |                 |
|                           | CFR\]      | Su       |                 |
|                           |            | bmitted? |                 |
+---------------------------+------------+----------+-----------------+
| 860.1200 Directions for   | Not        | No       | None            |
| Use                       | applicable |          |                 |
|                           | (NA)       |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1300 Plant Metabolism | NA         | Yes^4^   | 42376801^1^,    |
|                           |            |          | 20431471^2^,    |
|                           |            |          | 44654101^3^,    |
|                           |            |          | 44654102^3^     |
+---------------------------+------------+----------+-----------------+
| 860.1300 Livestock        | NA         | Reserved | None            |
| Metabolism                |            |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1340 Residue          |            |          |                 |
| Analytical Methods        |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Plant commodities         | NA         | Yes^6^   | PP 5F1613, PP   |
|                           |            |          | 0F0954, FDA PAM |
|                           |            |          | Vol. II         |
+---------------------------+------------+----------+-----------------+
| Livestock commodities     | NA         | Res      | None            |
|                           |            | erved^7^ |                 |
+---------------------------+------------+----------+-----------------+
| 860.1360 Multiresidue     | NA         | Res      | None            |
| Methods                   |            | erved^8^ |                 |
+---------------------------+------------+----------+-----------------+
| 860.1380 Storage          |            |          |                 |
| Stability Data            |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Plant commodities         | NA         | Yes^5^   | None            |
+---------------------------+------------+----------+-----------------+
| Processed commodities     | NA         | Reserved | None            |
+---------------------------+------------+----------+-----------------+
| Livestock commodities     | NA         | Reserved | None            |
+---------------------------+------------+----------+-----------------+
| 860.1400 Water, Fish, and | NA         | No       | None            |
| Irrigated Crops           |            |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1460 Food Handling    | NA         | No       | None            |
+---------------------------+------------+----------+-----------------+
| 860.1480 Meat, Milk,      | NA         | Res      | None            |
| Poultry, and Eggs         |            | erved^7^ |                 |
+---------------------------+------------+----------+-----------------+
| 860.1500 Crop Field       |            |          |                 |
| Trials                    |            |          |                 |
+---------------------------+------------+----------+-----------------+
| [Root and Tuber           |            |          |                 |
| Vegetables                |            |          |                 |
| Group]{.underline}        |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Beet, sugar, roots        | 0.1(N)     | Res      | None            |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| [Leaves of Root and Tuber |            |          |                 |
| Vegetables                |            |          |                 |
| Group]{.underline}        |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Beet, sugar, tops         | 0.1(N)     | Res      | None            |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| [Cereal Grains            |            |          |                 |
| Group]{.underline}        |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Barley, grain             | 0.1(N)     | Res      | 00117874^12^    |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, field, grain and    | 0.1(N),    | No^11^   | 00117874^12^    |
| aspirated grain           | grain      |          |                 |
|                           |            |          |                 |
| fractions                 | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, pop, grain          | None       | No^11^   | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, sweet, K+CWHR       | None       | No^11^   | None            |
|                           | E          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Oat, grain                | 0.1(N)     | Res      | 00117874^12^    |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Rice, grain               | 0.1(N)     | Res      | 00117874^12^    |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Sorghum, grain, grain and | 0.1(N),    | No^11^   | None            |
| aspirated                 | grain      |          |                 |
|                           |            |          |                 |
| grain fractions           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Wheat, grain and          | 0.1(N),    | Res      | 00117874^12^    |
| aspirated grain           | grain      | erved^9^ |                 |
|                           |            |          |                 |
| fractions                 | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| [Fodder, Forage, Hay, and |            |          |                 |
| Straw of Cereal Grains    |            |          |                 |
| Group]{.underline}        |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Barley, hay and straw     | 0.1(N),    | Res      | 00117874^12^    |
|                           | straw      | erved^9^ |                 |
|                           |            |          |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, field, forage and   | 0.1(N)     | No^11^   | 00117874^12^    |
| stover                    |            |          |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, pop, stover         | None       | No^11^   | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, sweet, forage and   | None       | No^11^   | None            |
| stover                    | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Oat, forage, hay, and     | 0.1(N)     | Res      | 00117874^12^    |
| straw                     |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Rice, straw               | 0.1(N)     | Res      | 00117874^12^    |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Sorghum, grain, forage    | 0.1(N)     | No^11^   | None            |
| and stover                |            |          |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Wheat, forage, hay, and   | 0.1(N)     | Res      | 00117874^12^    |
| straw                     |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| [Miscellaneous            |            |          |                 |
| Commodities]{.underline}  |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Cotton, undelinted seed   | 0.1(N),    | Res      | 00004239^13^    |
| and gin                   |            | erved^9^ |                 |
|                           | undelinted |          |                 |
| byproducts                | seed       |          |                 |
|                           |            |          |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| Safflower, seed           | 0.1(N)     | Res      | None            |
|                           |            | erved^9^ |                 |
|                           | \[§18      |          |                 |
|                           | 0.288(a)\] |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1520 Processed        |            |          |                 |
| Food/Feed                 |            |          |                 |
+---------------------------+------------+----------+-----------------+
| Barley                    | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Beet, sugar               | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Corn, field               | None       | No^11^   | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Cotton                    | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Oat                       | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Rice                      | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Safflower                 | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Sorghum                   | None       | No^11^   | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| Wheat                     | None       | Yes      | None            |
|                           | e          |          |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1650 Submittal of     | NA         | Yes^10^  | None            |
| Analytical Reference      |            |          |                 |
| Standards                 |            |          |                 |
+---------------------------+------------+----------+-----------------+
| 860.1850 Confined         | NA         | Res      | None            |
| Rotational Crops          |            | erved^9^ |                 |
+---------------------------+------------+----------+-----------------+
| 860.1900 Field Rotational | None       | Res      | None            |
| Crops                     | e          | erved^9^ |                 |
|                           | stablished |          |                 |
+---------------------------+------------+----------+-----------------+

1\. F. Fort, D187529, MRID 42376801, 00/00/0000.

2\. M. Perry, D221887, MRID 20431471, 5/11/1998.

3\. Both studies (MRID 44654101 and 44654102) are summarized in this
chemistry summary document. Full review of both studies is currently
underway.

4\. Confirmatory metabolism data should be submitted depicting the
nature of residues in wheat, cotton, and sugar beets.

5\. Storage stability data was not included with the original field
trial data submissions, therefore, it is required.

6\. The available enforcement method (Method B in PAM Vol. II.) is
outdated and uses toxic reagents; therefore, if an additional method
that is adequate for tolerance enforcement is available, it should be
submitted immediately for review. Additionally, if the requested
metabolism studies show additional residues are of concern and the
current enforcement method does not capture these additional residues,
development of a method capable of doing so will be required.

7\. This requirement is put on reserve pending the results from the
requested plant metabolism studies, and if required, the livestock
metabolism studies.

8\. If additional residues of concern are determined from the requested
metabolism studies, all additional residues of concern for tolerance
expression will need to be tested through Multiresidue Methods.

9\. This requirement is put on reserve pending the results from the
requested metabolism studies.

10\. Analytical standards must be replenished as requested by the
Repository. If additional residues are included in the tolerance
expression based on the requested metabolism data, analytical reference
standards should be submitted and replenished as requested by the
Repository.

11\. The registrants are not supporting use of TCMTB on corn and
sorghum; therefore, all tolerances associated with those uses should be
revoked.

12\. MRID 00117874 was reviewed in PP 2F1264.

13\. MRID 00004239 was reviewed in PP 0F0954.

**860.1200 Directions for Use**

[Product List]{.underline}

There are two Bayer and two Wilbur-Ellis end-use products containing the
active ingredient TCMTB, which are registered for use on domestically
grown food/feed crops as indicated in Table 5.

  ---------------------------------------------------------------------------------------
  **Table 5. TCMTB                                                
  End-use Products                                                
  (EPs) Registered                                                
  by Bayer and                                                    
  Wilbur-Ellis.**                                                 
  ----------------- ---------------- -------------- ------------- -----------------------
  EPA Reg. No.      Formulation^1^   Registrant     Product Name  Supported Seed
                                                                  Treatment Use Sites

  264-965           30% EC           Bayer          Busan^®^ 30A  cotton
                                     CropScience                  

  264-983^2^        5% EC            Bayer          Cotguard^®^   cotton
                                     CropScience                  

  2935-389          30% EC           Wilbur-Ellis   Nusan^®^ 30   barley, cotton, oat,
                                     Co.            EC            rice, safflower, sugar
                                                                  beet, and wheat

  2935-413^3^       9% SC            Wilbur-Ellis   Nu-Flow^®^ ND cotton on farm
                                     Co.                          
  ---------------------------------------------------------------------------------------

1\. EC = Emulsifiable Concentrate and SC = Soluble Concentrate.

2\. Formulation also contains Carboxin (PC Code 090201) at 14.35% and
Metalaxyl (PC Code 113501) at 2.4%.

3\. Formulation also contains Chloroneb (PC Code 027301) at 23.5%.

[Use Patterns]{.underline}

As an agricultural pesticide, TCMTB is a fungicide used as a seed
treatment on barley, corn, cotton, oat, rice, safflower, sorghum, sugar
beet, and wheat. It is used in commercial and on-farm settings. For
food/feed uses, Bayer is supporting TCMTB use as a seed treatment on
cotton only, while Wilbur-Ellis is supporting uses on barley, cotton,
oat, rice, wheat, safflower, and sugar beet (K. Jakob, TCMTB Use Closure
Memo, 1/30/2006). Use on corn and sorghum are not being supported. The
technical registrant of TCMTB, Buckman, has requested cancellation of
all food/feed uses (K. Jakob, TCMTB Use Closure Memo, 1/30/2006). An
analysis of the current labeling and available use information was
completed by HED. A summary of directions for the use of TCMTB is
presented below in Table 6.

+-----+------+-------+-------+-----------+------------+--------------+
| *   |      |       |       |           |            |              |
| *Ta |      |       |       |           |            |              |
| ble |      |       |       |           |            |              |
| 6.  |      |       |       |           |            |              |
| S   |      |       |       |           |            |              |
| umm |      |       |       |           |            |              |
| ary |      |       |       |           |            |              |
| of  |      |       |       |           |            |              |
| M   |      |       |       |           |            |              |
| axi |      |       |       |           |            |              |
| mum |      |       |       |           |            |              |
| Ap  |      |       |       |           |            |              |
| pli |      |       |       |           |            |              |
| cat |      |       |       |           |            |              |
| ion |      |       |       |           |            |              |
| Ra  |      |       |       |           |            |              |
| tes |      |       |       |           |            |              |
| for |      |       |       |           |            |              |
| R   |      |       |       |           |            |              |
| egi |      |       |       |           |            |              |
| ste |      |       |       |           |            |              |
| red |      |       |       |           |            |              |
| TC  |      |       |       |           |            |              |
| MTB |      |       |       |           |            |              |
| Foo |      |       |       |           |            |              |
| d/F |      |       |       |           |            |              |
| eed |      |       |       |           |            |              |
| S   |      |       |       |           |            |              |
| eed |      |       |       |           |            |              |
| Tre |      |       |       |           |            |              |
| atm |      |       |       |           |            |              |
| ent |      |       |       |           |            |              |
| U   |      |       |       |           |            |              |
| ses |      |       |       |           |            |              |
| .** |      |       |       |           |            |              |
+=====+======+=======+=======+===========+============+==============+
| EPA | Pro  | F     | Crop  | Ap        | Max. App.  | Max. App.    |
| R   | duct | ormul |       | plication | Rate       | Rate         |
| eg. | Name | ation |       | Equipment |            |              |
| No. |      |       |       |           | (fl oz/100 | (lbs ai/100  |
|     |      |       |       |           | lbs of     | lbs of seed) |
|     |      |       |       |           | seed)      |              |
+-----+------+-------+-------+-----------+------------+--------------+
| 2   | Busa | 30%   | c     | c         | 4.5 fl     | 0.093 lbs    |
| 64- | n^®^ | EC    | otton | ommercial | oz/100 lbs | a.i./100 lbs |
| 965 | 30A  |       |       | treater   | of seed    | of seed      |
+-----+------+-------+-------+-----------+------------+--------------+
| 2   | Cot  | 5% EC | c     | c         | 9.0 fl     | 0.032 lbs    |
| 64- | guar |       | otton | ommercial | oz/100 lbs | a.i./100 lbs |
| 983 | d^®^ |       |       | treater   | of seed    | of seed      |
+-----+------+-------+-------+-----------+------------+--------------+
| 29  | Nusa | 30%   | c     | c         | 5.0 fl     | 0.10 lbs     |
| 35- | n^®^ | EC    | otton | ommercial | oz/100 lbs | a.i./100 lbs |
| 389 | 30   |       |       | treater   | of seed    | of seed      |
|     | EC   |       |       |           |            |              |
+-----+------+-------+-------+-----------+------------+--------------+
|     |      |       | ba    | c         | 1.25 fl    | 0.026 lbs    |
|     |      |       | rley, | ommercial | oz/100 lbs | a.i./100 lbs |
|     |      |       | oat,  | treater   | of seed    | of seed      |
|     |      |       | rice, |           |            |              |
|     |      |       | wheat |           |            |              |
+-----+------+-------+-------+-----------+------------+--------------+
|     |      |       | saffl | c         | 2.0 fl     | 0.041 lbs    |
|     |      |       | ower, | ommercial | oz/100 lbs | a.i./100 lbs |
|     |      |       | sugar | treater   | of seed    | of seed      |
|     |      |       | beet  |           |            |              |
+-----+------+-------+-------+-----------+------------+--------------+
| 29  | Nu   | 9% SC | c     | c         | 19.7 fl    | 0.13 lbs     |
| 35- | -Flo |       | otton | ommercial | oz/100 lbs | a.i./100 lbs |
| 413 | w^®^ |       |       | treater   | of seed    | of seed      |
|     | ND   |       |       |           |            |              |
+-----+------+-------+-------+-----------+------------+--------------+
|     |      |       |       | on-farm   | 8.0 fl     | 0.051 lbs    |
|     |      |       |       | treater   | oz/100 lbs | a.i./100 lbs |
|     |      |       |       |           | of seed    | of seed      |
+-----+------+-------+-------+-----------+------------+--------------+

**860.1300 Nature of the Residue - Plants**

The reregistration requirements for plant metabolism have not been
fulfilled. In the Phase 4 review (3/11/1991) the registrant, Buckman,
was instructed to provide three new plant metabolism studies, one each
on corn or wheat, cotton and sugar beets, to determine if any uptake
occurred in the aerial portion and/or edible root portion of the growing
crop. Based on this information, a determination would be made as to
whether TCMTB uses are food or nonfood. Data have been submitted
depicting the uptake of TCMTB in corn, cotton, safflower, and wheat and
were found to be inadequate due to lack of identification and/or
characterization of parent and/or metabolites. Additional metabolism
studies conducted with tomatoes and melons have been submitted; however,
translation to the currently registered crops is not adequate for
reregistration purposes. Confirmatory metabolism data should be
submitted depicting the nature of residues in wheat, cotton, and sugar
beets. Adequate identification and/or characterization of parent and/or
metabolites should be conducted as required by OPPTS 860 Series
Guidelines.

The Risk Assessment Review Committee (RARC) met and determined that the
interim residue of concern for tolerance expression and risk assessment
is TCMTB in/on plants (P. Deschamp, Report of the RARC, 1/11/2006). This
is a preliminary decision dependent on the results from the requested
metabolism data. For drinking water, the RARC decided that the residues
of concern for risk assessment are TCMTB and 2-MBT. Summary of the
preliminary decisions concerning the residues of concern in plants and
drinking water are presented below in Table 7.

  -------------------------------------------------------------------------------
  **Table 7.                                                 
  Summary of                                                 
  TCMTB Residues                                             
  to be Included                                             
  in the Risk                                                
  Assessment and                                             
  Tolerance                                                  
  Expression.**                                              
  --------------- --------------------- -------------------- --------------------
  Matrix                                Residues Included in Residues Included in
                                        Risk Assessment      Tolerance Expression

  Plants          Primary crop -        TCMTB                TCMTB
                  barley, cotton, oat,                       
                  rice, safflower,                           
                  sugar beet, and wheat                      

                  Rotational crop       NA = not applicable  NA

  Livestock       Ruminant              NA                   NA

                  Poultry               NA                   NA

  Drinking water                        TCMTB and 2-MBT      NA
  -------------------------------------------------------------------------------

All submitted studies are summarized below. No data have been submitted
depicting the uptake of TCMTB in sugar beets.

[Corn, Cotton, Safflower, and Wheat (MRID 42376801 and
43147201)]{.underline}

Buckman submitted a study (MRID 42376801) entitled \"Uptake and
Translocation of ^14^C-Busan 30A Used in Seed Treatment Combustion
Analysis Phase\".

Uniformly labelled ^14^C-TCMTB in the benzene ring was applied (as a
solution of unknown concentration in an unspecified solvent) to four
seed types, corn, cotton, safflower, and wheat at the maximum
application rate at the time. No data were submitted depicting residues
in/on sugarbeets. The specific activity and radiopurity of the test
substance were determined to be 45,600 dpm/ug (5.26 mCi/mmol) and 100%,
respectively. Seeds were added to amber bottles that contained the
radioactive material and placed on a roller for an hour to insure
uniform coating. Acetonitrile washes of ten seeds were analyzed by
liquid scintillation counting (LSC) and the washed seeds were combusted
to determine the rate of application. The remaining seeds were planted.
Samples were taken from the aerial portion of the plant at various
growth stages. Corn silage, haylage, grain and stover; wheat forage,
hay, grain and straw; safflower forage, seed, thinnings, and stalk; and
cotton forage samples were obtained. Control samples showed some uptake
of radioactivity which increased with time. The registrant concluded
that this was a result of housing the control samples in the same
greenhouse with the treated plants. The Health Effects Division (HED)
previously concurred with this assumption; however, some of the control
samples contained higher radioactive residues than its treated
counterpart. The treated samples were stored frozen before processing
and were analyzed by high-performance liquid chromatography (HPLC) using
an ultraviolet detector (UV).

Radioactive residues were found in all plant parts with the least amount
of residue in corn commodities (0.0011-0.0021 ppm). The highest residues
were found in cotton forage samples (2.7856 ppm). Cotton forage samples
were analyzed for the presence of 2-MBT. No 2-MBT residues were found in
the aqueous or organic cotton forage extracts. During the HPLC analysis
of both the aqueous and organic extracts, a peak was noted to elute with
a retention time similar to that of TCMTB. The identity of this peak was
not confirmed by alternative means. Additionally, the registrant stated
that subsequent analyses for the presence of 2-MBT in other plant
extracts were being performed; however, no additional data have been
submitted to the Agency for review.

Buckman submitted an addendum (MRID 43147201) to the previous study
report (MRID 42376801) evaluating the uptake and translocation of
C^14^-TCMTB in seed treatment of corn, wheat, safflower and cotton. This
addendum includes the results of combustion analysis of radioactive
residues in cotton seed, lint, and stalk. These results were not
included in the previous study report because the treated cotton plants
were not mature when the report was prepared. Table 8 below presents the
results of the initial study and the addendum report.

+-------------+-------------+-------------+-------------+-------------+
| **Table 8.  |             |             |             |             |
| Ra          |             |             |             |             |
| dioactivity |             |             |             |             |
| in Corn,    |             |             |             |             |
| Cotton,     |             |             |             |             |
| Safflower,  |             |             |             |             |
| and         |             |             |             |             |
| Wheat.**    |             |             |             |             |
+=============+=============+=============+=============+=============+
| Crop        | Harvest     | Days        | Total       | Corrected   |
|             | Point       | Harvested   | DPM/G^1^    | ppm^2^      |
|             |             | After       |             |             |
|             |             | Planting    |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Corn        | Haylage     | 62 days     | 68.4        | 0.0015      |
|             |             |             |             |             |
|             | Silage      | 114 days    | 95.8^3^     | 0.0021      |
|             |             |             |             |             |
|             | Grain       | 139 days    | 54.7        | 0.0012      |
|             |             |             |             |             |
|             | Stover      | 139 days    | 50.2        | 0.0011      |
+-------------+-------------+-------------+-------------+-------------+
| Cotton      | Forage      | 52 days     | 127000      | 2.7856      |
|             |             |             |             |             |
|             | Seed        | 211 days    | 192         | 0.0041      |
|             |             |             |             |             |
|             | Lint        | 211 days    | 264         | 0.0058      |
|             |             |             |             |             |
|             | Stalk       | 211 days    | 502         | 0.0110      |
+-------------+-------------+-------------+-------------+-------------+
| Safflower   | Forage      | 49 days     | 948.5       | 0.0208      |
|             |             |             |             |             |
|             | Seed        | 147 days    | 478.8       | 0.0105      |
|             |             |             |             |             |
|             | Stalk       | 147 days    | 1860        | 0.0408      |
+-------------+-------------+-------------+-------------+-------------+
| Wheat       | Forage      | 22 days     | 18660       | 0.4092      |
|             |             |             |             |             |
|             | Hay         | 63 days     | 1158        | 0.0254      |
|             |             |             |             |             |
|             | Grain       | 141 days    | 538.1       | 0.0118      |
|             |             |             |             |             |
|             | Straw       | 141 days    | 3083        | 0.0676      |
+-------------+-------------+-------------+-------------+-------------+

1\. Total dpm/g = corrected ppm X specific activity.

2\. Corrected for machine recovery and matrix recovery.

3\. Sample was combusted twice. Number represents average of both
combustions.

Residues of 0.0011 ppm to 2.7856 ppm total radioactivity (TCMTB
equivalents) were found demonstrating uptake of TCMTB residues in crop
parts. Identification and/or characterization of parent and/or
metabolites were not performed. The solvent and TCMTB concentration in
the treatment solution was not provided as well as the seed treatment
rate. Both of these should be comparable with the
commercial/agricultural practices. Residues were found above 0.005 ppm,
which is the trigger value for food-use classification. Additional
metabolism studies should be conducted with corn or wheat, cotton, and
sugar beets where identification and/or characterization of parent
and/or metabolites are completed.

[Melon (MRID 44654101)]{.underline}

Transplanted melon plants were grown in two confined plots. The treated
plot received two soil-drench applications of ^14^C-TCMTB containing
20.0 mCi and supplementary unlabelled TCMTB in blank formulation of
Busan 30 WB, so that the applications were equivalent to approximately
5.0 lb a.i./A. The applications were made at the time of transplanting
and again 14 days later. Immature melons (0.78 kg) were sampled at a
preliminary sampling, at 29 days after last application. At the sampling
at maturity, approximately 5.4 kg of melons was sampled and 0.59 kg of
mature plant material was also taken. At all sampling events, the plant
material was promptly frozen. It was stored frozen and shipped frozen to
the analytical laboratory. The melons were stored and shipped under
refrigeration to facilitate handling and chopping at the analytical
laboratory.

On receipt at Xenobiotic Laboratories, the fruit and plant material were
frozen and homogenized and samples were taken for determination of the
total radioactive residue (TRR) of each matrix. No radioactivity was
detected in any of the untreated samples (\<0.001 ppm). The immature
treated melons contained 0.304 ppm and the immature plant material
contained 0.532 ppm and the mature plant material contained 8.00 ppm of
radioactivity as TCMTB-equivalents.

The parent compound, TCMTB, was found only in the plant material and at
very low concentration, 0.073 ppm. One principle metabolite, 2-BTSA, was
found in both the fruit and plant material. It was present in the fruit
at 0.170 ppm and in the plant material at 1.12 ppm. 2-OH-BT and 2-MBT
were also detected, but at \<0.01 ppm in fruit and at 0.203 ppm and
0.010 ppm in the plant, respectively. Two positional isomers of
OH-2-BTSA were also detected, but primarily in the plant at 0.113 ppm
and 0.097 ppm. In addition, ^14^C incorporation was also detected in
sucrose, fructose, and glucose at more than 27% of TRR. Table 9 presents
the results of the melon metabolism study.

  ------------------------------------------------------------------------
  **Table 9. Major                                           
  TCMTB Metabolites                                          
  Found in Melons.**                                         
  ------------------ ------------ ------------ ------------- -------------
  Compound           Residue                                 

                     Melon Fruit               Melon Plant   

                     ppm          \%           ppm           \%

  TCMTB              \<0.001      0            0.073         0.9

  2-BTSA             0.170        31.9         1.12          14.0

  2-OH-BT            0.007        1.3          0.203         2.5

  2-MBT              0.004        0.7          0.010         0.1

  OH-2-BTSA^1^       0.006        1.1          0.113         1.4

  OH-2-BTSA^1^       0.039        7.3          0.097         1.2

  Sugars^2^          0.144        27.1         0.032         0.4

  **Totals**         0.370        69.4         1.65          20.5

  Post-Extraction    0.109        20.5         5.80          72.5
  Solids                                                     

  **Grand Totals**   0.479        89.9         7.45          93.0
  ------------------------------------------------------------------------

1\. Two positional isomers of hydroxy-2-benzothiazolesulfonic acid were
detected. The exact position of the hydroxyl group could not be
determined.

2\. Sucrose + glucose + fructose with ^14^C incorporation.

[Tomato (MRID 44654102)]{.underline}

Transplanted tomato plants were grown in two confined plots. The treated
plot received two soil-drench applications of ^14^C-TCMTB containing
20.0 mCi and supplementary unlabelled TCMTB in blank formulation of
Busan 30 WB, so that the applications were equivalent to approximately
5.0 lb a.i./A. The applications were made at the time of transplanting
and again 14 days later. Immature tomatoes (0.24 kg) were sampled at a
preliminary sampling, at 29 days after last application. Tomatoes were
sampled twice at maturity, approximately 1.0 kg of ripe tomatoes was
sampled at 56 days after last application and 1.5 kg of ripe tomatoes as
well as 1.2 kg of green tomatoes were sampled two weeks later. In
addition, approximately 1.0 kg of mature plant material was also taken.
Samples were taken from the untreated control plants on the same
schedule. At all sampling events, the plant material was promptly
frozen. It was stored frozen and shipped frozen to the analytical
laboratory. The tomatoes were stored and shipped under refrigeration to
facilitate handling and chopping at the analytical laboratory.

On receipt at Xenobiotic Laboratories, the fruit and plant material were
frozen and homogenized and samples were taken for determination of the
total radioactive residue (TRR) of each matrix. No radioactivity was
detected in any of the untreated samples (\<0.001 ppm). The immature (29
day sampling) treated tomatoes contained 0.298 ppm and the immature
plant material contained 6.41 ppm of radioactivity as TCMTB-equivalents.
The mature (56 day sampling) treated tomatoes contained 0.221 ppm and
the mature plant material contained 4.08 ppm of radioactivity as
TCMTB-equivalents.

The parent compound, TCMTB, was not found in the tomato fruit of in the
plant material, \<0.001 ppm. One principle metabolite, 2-BTSA, was found
in both the fruit and plant material. It was present in the fruit at
0.136 ppm and in the plant material at 1.33 ppm. Two positional isomers
of OH-2-BTSA were also detected, but only in significant quantities in
the plant material (0.272 ppm and 0.590 ppm). In addition, ^14^C
incorporation was also detected in sucrose, fructose, and glucose at
more than 18% of TRR. Table 10 presents the results of the tomato
metabolism study.

  ------------------------------------------------------------------------
  **Table 10. Major                                          
  TCMTB Metabolites                                          
  Found in                                                   
  Tomatoes.**                                                
  ------------------ ------------ ------------ ------------- -------------
  Compound           Residue                                 

                     Tomato Fruit              Tomato Plant  

                     ppm          \%           ppm           \%

  TCMTB              \<0.001      0            \<0.001       0

  2-BTSA             0.136        61.7         1.33          32.6

  OH-2-BTSA^1^       0.015        6.9          0.272         6.7

  OH-2-BTSA^1^       0.004        1.6          0.590         14.5

  Sugars^2^          0.031        14.1         0.193         4.7

  Unidentified       0.008        3.6          0.494         12.1

  **Totals**         0.194        87.9         2.88          70.6

  Post-Extraction    0.017        7.8          0.927         22.7
  Solids                                                     

  **Grand Totals**   0.211        95.7         3.81          93.3
  ------------------------------------------------------------------------

1\. Two positional isomers of hydroxy-2-benzothiazolesulfonic acid were
detected. The exact position of the hydroxyl group could not be
determined.

2\. Sucrose + glucose + fructose with ^14^C incorporation.

The reregistration requirements for plant metabolism have not been
fulfilled. Data have been submitted depicting the uptake of TCMTB in
corn, cotton, safflower, and wheat and were found to be inadequate due
to lack of identification and/or characterization of parent and/or
metabolites. Additional metabolism studies conducted with tomatoes and
melons have been submitted; however, translation to the currently
registered crops is not adequate for reregistration purposes.
Confirmatory metabolism data should be submitted depicting the nature of
residues in wheat, cotton, and sugar beets. Adequate identification
and/or characterization of parent and/or metabolites should be conducted
as required by OPPTS 860 Series Guidelines. The Risk Assessment Review
Committee (RARC) met and determined that the interim residue of concern
for tolerance expression and risk assessment is TCMTB in/on plants (P.
Deschamp, Report of the RARC, 1/11/2006). This is a preliminary decision
and additional confirmatory data should be submitted in a timely manner.
For drinking water, the RARC decided that the residues of concern for
risk assessment are TCMTB and 2-MBT.

The determination of the residues of concern in plant commodities is
based on the tomato and melon metabolism studies and the available
toxicity data. 2-BTSA was found at significant levels (62% in tomato
fruit); however, it should be excluded as a residue of concern because
it is expected to be less toxic than the parent TCMTB. 2-BTSA is likely
to not contribute significantly to the chronic toxicity of the parent
based on the following considerations:

1.  2-BTSA has a very polar structure lacking the structural features of
    the parent (TCMTB) that might lead to toxicologically significant
    species. Although the mode of toxic action of the parent is not
    known, its thiocyanomethylthio group is likely to be metabolized to
    toxic species. This group is not present in 2-BTSA. Thus, 2-BTSA
    cannot contribute to toxicity via this group.

2.  If the benzimidazole ring of TCMTB is involved in its toxic effects
    by biotransformation to electrophilic species, 2-BTSA is not likely
    to undergo this type of biotransformation. 2-BTSA, being a sulfonic
    acid, is expected to undergo little or no metabolism. Small-molecule
    sulfonic acids generally undergo little or no biotransformation. For
    example, methanesulfonic, benzenesulfonic, and naphthylaminesulfonic
    acids are excreted untransformed in laboratory animals (Biological
    Basis of Detoxication, Caldwell J. & Jakoby W.B. \[eds\], 1984, p.
    162).

3.  In a chemical with a mercapto group (-SH), oxidation of the mercapto
    group to the corresponding sulfonic acid is known to produce a
    marked decrease in toxicity. For example, phenyl mercaptan (i.e.
    benzenethiol) is a fairly toxic chemical producing neurotoxicity,
    liver toxicity, and other effects and has a rat acute oral LD~50~ of
    46 mg/kg (McCord & Witheridge, 1949, cited in NIOSH website). In
    contrast, the oxidized form, benzenesulfonic acid is reported as
    having a rat acute oral LD~50~ of 890 mg/kg (Benzenesulfonic acid
    MSDS). This marked decrease of toxicity can be attributed to
    polarity resulting from the replacement of the -SH group with a
    sulfonic acid group.

4.  2-BTSA is the oxidized (sulfonic acid) form of 2-MBT; thus, it is
    expected to be equally or less systemically toxic than 2-MBT by
    analogy with the benzenethiol/benzenesulfonic acid pair of
    compounds. Barring high-dose effects such as gastrointestinal
    effects, the chronic RfD for 2-MBT of 0.6 mg/kg/day set by the HED
    RfD/Peer Review suggests that the chronic toxicity of 2-BTSA is much
    smaller than that of the parent TCMTB with a chronic RfD of 0.013
    mg/kg/day. Although there are concerns for the carcinogenic
    potential of 2-MBT (Group C), there are no such concerns for 2-BTSA
    due to its very high polarity and probable absence of metabolism.

Additionally, 2-MBT and other TCMTB metabolites were not found at
significant levels to be considered residues of concern. Therefore, only
TCMTB should be considered a residue of concern in plant commodities.

For drinking water, the residues of concern should include TCMTB and
2-MBT and is based on the available aerobic soil metabolism study (MRID
43532201). 2-BTSA was found at 71% TRR; however, it should be excluded
as a residue of concern for reasons noted in the above section. 2-MBT
was found at 30% TRR after 1.5 days post-treatment and should be
considered a residue of concern. 2-MBT is distinctly less toxic than the
parent; however, it can not be ruled out as a residue of concern and
should be included in the dietary risk assessment. All other metabolites
were not found at significant levels; therefore, they should not be
considered residues of concern.

Number range CHAPTER**860.1300 Nature of the Residue -- Livestock**

Livestock metabolism studies may be required if the requested plant
metabolism studies show uptake of residues. If livestock metabolism
studies are required, the registrant must provide poultry and ruminant
metabolism studies following OPPTS 860 Series Guidelines.

**860.1340 Residue Analytical Methods -- Plants**

A tolerance enforcement method is available for determining
thiobenzothiazole-containing residues in barley, corn, cotton, oat,
rice, safflower, sugar beet, and wheat. This method was originally
submitted with Pesticide Petition (PP) 0F0954 by Buckman. Residues are
extracted by blending with water and the extract is refluxed with NaOH.
After partition with CH~2~Cl~2~, glacial acetic acid and sulfuryl
chloride are added to convert the residues to 2-chlorobenzothiazole,
which is determined by a gas-liquid chromatography (GLC) method using an
electron capture detector (ECD). The quantitation limit of the method
has been determined at 0.10 ppm. This method is listed as Method B in
PAM Vol. II. The method is outdated and uses toxic reagents; therefore,
if an additional method that is adequate for tolerance enforcement is
available, it should be submitted immediately for review.

Two data-collection methods are available for determining
thiocyanate-containing residues. The first method was originally
submitted with PP 0F0954 by Buckman for the determination of residues in
barley, corn, cottonseed, oat, rice, and wheat. Residues are extracted
with benzene and the extract is cleaned up with liquid-liquid
extractions (isooctane to H~2~SO~4~-water and then H~2~SO~4~-water to
CH~2~Cl~2~). The TCMTB residue is heated with sodium polysulfide
solution to liberate thiocyanate ion. Bromine is added to convert the
thiocyanate to cyanogens bromide; then the cyanogen bromide is treated
with pyridine-benzidine reagent to form an intensely colored dye. The
absorbance of the dye solution is determined at 532 nm. In a method
tryout, the Agency obtained recoveries of 90% and 110% (duplicate
samples) at the 0.10 ppm fortification level and 105% and 115%
(duplicate samples) at the 0.20 ppm fortification level. The
quantitation limit of the method has been determined at 0.10 ppm. The
method is listed as Method I in PAM Vol. II.

The second method was originally submitted with PP 5F1613 by Buckman for
the determination of residues in safflower seed, sorghum grain and
foliage, and sugar beet and foliage. TCMTB is extracted from samples by
blending with acetone. The extract is filtered and cleaned up on a
Florisil column, and TCMTB is eluted with benzene. After liquid-liquid
partitioning, the same procedure described above for Method I is
followed. Samples of safflower seed, sorghum grain and foliage, and
sugar beet and foliage were fortified with 0.10 ppm to 0.30 ppm TCMTB
and recoveries ranged from 70% to 93%. The quantitation limit of the
method has been determined at 0.10 ppm. The method is listed as Method A
in PAM Vol. II.

If the requested metabolism studies show additional residues are of
concern and the current enforcement method does not capture these
additional residues, development of a method capable of doing so will be
required.

**860.1340 Residue Analytical Methods - Livestock**

This requirement is put on reserve pending the results from the
requested plant metabolism studies, and if required, the livestock
metabolism studies.

**860.1360 Multiresidue Methods**

Number range CHAPTERThere is no information in the review documents
regarding submittal of data for FDA Multiresidue Methods by the
petitioner. However, the FDA PESTDATA database dated 11/2001 (PAM Volume
I, Appendix I) indicates that TCMTB *per se* is completely recovered
(\>80%) using Multiresidue Methods Section 302 (Luke Method), but is
only partially recovered (50-80%) using 303 (Mills, Onley, Gaither
Method) and 304 (Mills fatty food Method).

If additional residues of concern are determined from the requested
metabolism studies, all additional residues of concern for tolerance
expression will need to be tested through Multiresidue Methods.

**860.1380 Storage Stability**

Storage stability data for TCMTB in/on barley, cotton, oat, rice, wheat,
safflower, and sugar beet have not been submitted by the registrant. No
data were provided on how long samples from the submitted field trials
were stored prior to analysis; therefore, storage stability data for the
previously submitted field trials are required and should be submitted
immediately. Additionally, if field trials are required or additional
uses are requested, storage stability data will be required under this
guideline topic.

**860.1400 Water, Fish, and Irrigated Crops**

TCMTB is not intended for direct use on water and aquatic food and feed
crops; therefore, no residue chemistry data are required under this
guideline topic.

**860.1460 Food Handling**

TCMTB is not intended for use in food-handling establishments;
therefore, no residue chemistry data are required under this guideline
topic.

**860.1480 Meat, Milk, Poultry, and Eggs**

TCMTB is not intended for application to livestock. The grain crops,
byproducts, and forages are livestock feed items. It is therefore
necessary to consider if TCMTB residues are transferred to meat, milk,
poultry, and eggs of livestock through ingestion of the residue-bearing
commodities.

It has been indicated in the foregoing considerations that the nature of
residue in plants has not been adequately described. In the absence of
such data, the residue level is unclear.

No livestock feeding studies have been submitted. If the requested
residue data show finite residues in the feed items, livestock feeding
studies would be essential to an evaluation of the transfer of residues
to milk, meat, poultry, and eggs. Therefore, no valid conclusions
relative to 40 CFR §180.6 (the necessity of tolerances in livestock
commodities) can be made in the absence of livestock feeding studies.

**860.1500 Crop Field Trials**

The available field trial data are not adequate according to current
OPPTS 860 Series Guidelines. The correct number of field trials, number
samples collected, and locations of trials are all insufficient.
Additionally, no storage stability data were submitted with the field
trial studies and the application rates are unknown for the barley,
corn, oat, rice, and wheat studies. The method used for determining
residues in barley, corn, oat, rice, and wheat is the data-collection
method which only determines the thiocyanate ion (Method I or A in PAM
Vol. II). The method used for determining residues in cotton is the
tolerance enforcement method which determines
thiobenzothiazole-containing residues (Method B in PAM Vol. II). If the
requested metabolism studies show that additional metabolites of concern
are expected, new field trials should be conducted in which the method
samples for all residues of concern as determined by the tolerance
expression. Field trial data are not available for sugar beets;
therefore, magnitude of residue data in sugar beets should be submitted
following all OPPTS 860 Series Guidelines.

[Cotton (MRID 00004239)]{.underline}

Cotton: Four studies reflecting seed treatments of 2-3 oz of Busan
72/100 lbs seed are reported. The exact application rate in lbs a.i./100
lbs of seed is unknown. Control values ranged from 0.01 ppm to 0.04 ppm,
with values from treated samples ranging from 0.01 ppm to 0.09 ppm.
These data are inadequate to determine whether of not real residues are
present. Additionally, no data on cotton gin byproducts have been
provided and are currently required.

[Barley, Corn, Oat, Rice, and Wheat (MRID 00117874)]{.underline}

Barley: Grain and foliage samples were obtained from crops in Wisconsin,
Tennessee, and North Dakota which had received seed treatments of 0.7x
to 5.6x the original application rate. Apparent residues in grain or
foliage were 0.01-0.04 ppm. Untreated grain or foliage samples had
residues of 0.01-0.04 ppm.

Corn: Grain and foliage samples were obtained from crops in Indiana,
Illinois, Kansas, Missouri, and Wisconsin which had received seed
treatments of 1x to 1.5x the original application rate. Apparent
residues in grain or foliage were 0.01-0.04 ppm. Untreated grain and
foliage samples had residues of 0.01-0.05 ppm.

Oat: Grain and foliage samples were obtained from crops in Arkansas and
Wisconsin which had received seed treatments of 0.6x to 1.4x the
original application rate. Apparent residues in grain and foliage were
0.02-0.04 ppm. Residues in untreated grain and foliage samples were
0.02-0.04 ppm.

Rice: Grain and foliage samples were collected from crops in Arkansas
and Louisiana which had received seed treatments of 1x to 2.4x the
original application rate. Apparent residues in grain and foliage were
0.02-0.04 ppm. Residues in untreated grain or foliage were 0.02-0.04
ppm.

Wheat: Samples of grain and foliage were taken from crops in Arkansas
and North Dakota which had received seed treatments of 1.2x to 5.6x the
original application rate. Apparent residues in grain and foliage were
0.02-0.04 ppm. Residue in untreated grain and foliage samples were
0.02-0.04 ppm.

A comparison of the data for the field studies of all the crops
indicates that there is no significant difference between residue levels
for the treated and untreated crops (grain or foliage). It may be
concluded that no residues of the parent compound, TCMTB, are likely to
occur in the grain or foliage of barley, cotton, corn, oats, rice, and
wheat from the current use pattern. Thus, the tolerance level of 0.1 ppm
represents the analytical method's sensitivity rather than determinable
residues.

The above conclusions apply only to the residues of the parent compound.
No data have been submitted indicating if plant residues contain
components other than the parent compound. If additional metabolism data
show the presence in the residue of components other than the parent
compound in significant quantities, then residue data on the subject
crops may be necessary.

**860.1520 Processed Food and Feed**

No processing studies have been submitted. Once the requested metabolism
studies have been submitted, reviewed, and the metabolites of concern
are determined, data should be submitted which show whether residues
concentrate in the byproducts of the registered raw agricultural
commodities. If concentration occurs, and the concentrated residue
levels exceed the proposed tolerance, then food additive tolerances to
cover such residues will be necessary.

**860.1650 Submittal of Analytical Reference Standards**

Number range CHAPTERAn analytical reference standard for TCMTB was
submitted by Buckman in February of 2002 and expires February of 2012.
The standard is available at the EPA National Pesticide Standards
Repository. If additional residues are included in the tolerance
expression based on the requested metabolism data, analytical reference
standards should be submitted and replenished as requested by the
Repository.

**860.1850 Confined Accumulation in Rotational Crops and 860.1900 Field
Accumulation in Rotational Crops**

TCMTB treated seeds were planted in silt loam and yellow clay loam
soils. The seeds were treated at 0.75-4.5 fl oz/100 lbs seed. Less than
0.10 ppm of TCMTB residues were noted in the soils at intervals of 30
days and beyond.

Loess and clay loam soils were treated in-furrow or broadcast at 1.2-1.6
lbs a.i./100 lbs seed (9x the current maximum seed treatment rate).
Residues were 1.1-1.7 ppm at 30 days, 0.6-1.0 ppm at 100 days, less than
0.10-1.0 ppm at 189 days, and less than 0.10 ppm at 215 days.

Sandy loam and silt loam soils were treated at 0.72-4.32 lb a.i./100lbs
seed. Residues were less than 0.10-1.0 ppm at 30 days and less than 0.10
ppm at 60 days.

It is unclear which method was used to determine residue levels in the
above soil persistence studies. The registrant should provide method
data along with storage stability data in order for the data to be
considered scientifically adequate. However, with the exception of
storage stability and method data, soil persistence is not likely to be
a concern with respect to follow-up crops. However, the method used is
unknown and the exact compounds that make up the residues found is
unknown; therefore, this data requirement is put on reserve awaiting
submission of the requested data and pending the results from the plant
metabolism studies.

**Tolerance Reassessment Summary**

Number range CHAPTERTolerances for residues in/on plant livestock
commodities have been established under 40 CFR §180.288. Number range
CHAPTERThe tolerances for residues of TCMTB in/on plant commodities is
expressed in terms of residues of TCMTB *per se*
\[(2-benzothiazolylthio)methyl thiocyanate\].

[Tolerances Established Under 40 CFR §180.288]{.underline}

Confirmatory metabolism data conducted with wheat, cotton, and sugar
beet are requested to determine the nature of residues in plants.
Depending on the results from the requested confirmatory metabolism
studies, additional guideline requirements may be requested for:
livestock metabolism; enforcement and data-collection methods;
multiresidue methods; storage stability; and livestock, crop, processed
commodity, and rotational crop magnitude of residue studies. A summary
of the TCMTB tolerance reassessment is presented below in Table 11.

[Tolerances To Be Proposed Under 40 CFR §180.288]{.underline}

Number range CHAPTERBecause of changes to Table 1 (OPPTS 860.1000),
tolerances for barley hay and cotton gin byproducts must be proposed.

  ---------------------------------------------------------------------------
  **Table 11.                                       
  Tolerance                                         
  Reassessment                                      
  Summary for                                       
  TCMTB.**                                          
  ------------------ ------------- ---------------- -------------------------
  **Commodity**      **Current     **Tolerance      **Comment/\[Correct
                     Tolerance**   Reassessment**   CommodityDefinition\]**

  **Tolerances                                      
  Established Under                                 
  40 CFR §180.288:**                                

  Barley, grain      0.1 (N^1^)    TBD^2^           

  Barley, straw      0.1 (N)       TBD              

  Beet, sugar, roots 0.1 (N)       TBD              

  Beet, sugar, tops  0.1 (N)       TBD              

  Corn, grain        0.1 (N)       Revoke           The registrants do not
                                                    intend to support use of
                                                    TCMTB on corn.

  Corn, forage       0.1 (N)       Revoke           The registrants do not
                                                    intend to support use of
                                                    TCMTB on corn.

  Corn, stover       0.1 (N)       Revoke           The registrants do not
                                                    intend to support use of
                                                    TCMTB on corn.

  Cotton, forage     0.1 (N)       Revoke           No longer considered a
                                                    significant livestock
                                                    feed item.

  Cotton, undelinted 0.1 (N)       TBD              
  seed                                              

  Oat, forage        0.1 (N)       TBD              

  Oat, grain         0.1 (N)       TBD              

  Oat, hay           0.1 (N)       TBD              

  Oat, straw         0.1 (N)       TBD              

  Safflower, seed    0.1 (N)       TBD              

  Sorghum, grain,    0.1 (N)       Revoke           The registrants do not
  forage                                            intend to support use of
                                                    TCMTB on sorghum.

  Sorghum, grain,    0.1 (N)       Revoke           The registrants do not
  grain                                             intend to support use of
                                                    TCMTB on sorghum.

  Sorghum, grain,    0.1 (N)       Revoke           The registrants do not
  stover                                            intend to support use of
                                                    TCMTB on sorghum.

  Wheat, forage      0.1 (N)       TBD              

  Wheat, grain       0.1 (N)       TBD              

  Wheat, hay         0.1 (N)       TBD              

  Wheat, straw       0.1 (N)       TBD              

  **Tolerances To Be                                
  Proposed Under 40                                 
  CFR §180.288:**                                   

  Barley, hay        None          TBD              
                     established                    

  Cotton, gin        None          TBD              
  byproducts         established                    
  ---------------------------------------------------------------------------

1\. N = Negligible. The "N" designation must be removed from all
tolerances.

2\. TBD = To be determined. Tolerances cannot be determined at this time
because additional data are required.

**Codex Harmonization**

There are no Codex maximum residue limits (MRLs) for TCMTB; therefore,
no questions of compatibility with U.S. tolerances exist.

**Bibliography**

**Agency Memoranda Citations**

  -------------- --------- -------- --------- ---------- ---------- --------------------------
  **Table 12.                                                       
  Agency                                                            
  Memoranda                                                         
  Citations.**                                                      

  Date           DP        PP No.   From      To         MRID Nos.  Subject
                 Barcode                                            

  12/16/1993     D187529   None     F. Fort   V.         42376801   TCMB. Uptake of ^14^C from
                                              Dietrich              Seed Treatment. Case No.
                                              and B.                2625. Chemical No. 035603.
                                              Sidwell               MRID No. 42376801. CBRS
                                                                    No. 11294. DP Barcode
                                                                    D187529.

  5/11/1998      D221887   None     M. Perry  M.         20431471   TCMTB. Uptake of ^14^C
                                              Swindell              from seed treatment. Case
                                                                    No. 2625. Chemical No.
                                                                    035603. MRID No. 43147201.
                                                                    DP Barcode D221887.

  7/31/1970      None      0F0954   A.        None       None       PP #0F0954: TCMTB on
                                    Rathman                         cotton, as amended.
                                                                    Evaluation of analytical
                                                                    method and residue data.

  9/23/1972      None      2F1264   A. Smith  None       None       PP #2F1264. TCMTB in small
                                                                    grain crops.
  -------------- --------- -------- --------- ---------- ---------- --------------------------

**Master Record Identification Numbers**

00004239 Wilbur-Ellis Company (1979) Residue Data Summary. Unpublished
study including letter dated Oct 16, 1978 from J.H. Stoner to Dave T.
Schulteis, received Feb 6, 1979 under 2935-413; pre-pared in cooperation
with Stoner Laboratories; CDL:237334-A

00004241 Wilbur-Ellis Company (1979) Results of Tests on the Amount of
Resi- due Remaining, Including a Description of the Analytical Method:
Nu-Flow ND. Unpublished study received Feb 6, 1979 under 2935-413;
CDL:237335-B.

00046073 Buckman Laboratories, Incorporated (1975) Analytical Procedures
and Results of Residue Analyses: Busan 30. Undated method. Unpublished
study received Nov 12, 1976 under 7F1885; CDL: 095601-D.

00078556 Buckman Laboratories, Incorporated (1972) Analytical Procedures
and Results of Residue Analyses: Busan 30. Includes undated methods
entitled: Analyses of 2-(thiocyanomethylthio)benzothiazole in soil;
Regulatory method of analysis. Unpublished study re- ceived Mar 26, 1975
under 4F1613; CDL:095525-F.

00112618 Buckman Laboratories, Inc. (1970) Results of Tests on the
Amount of Residue Remaining, Including a Description of the Analytical
Method: 2-(Thiocyanomethylthio)benzothiazole. Compilation; unpublished
study received on unknown date under 0F0954; CDL: 091624-K.

00117874 Buckman Laboratories, Inc. (1967) Study: TCMTB Residues in
Selected Grains). (Compilation; unpublished study received Sep 28, 1972
under 2F1264; CDL:091795-A.

00124027 Buckman Laboratories, Inc. (19??) Analysis of Grains for
Thioben- zothiazole-Containing Residues. Unpublished study received Oct
20, 1972 under 2F1264; CDL:094858-A.

00136342 Buckman Laboratories, Inc. (19??) Analysis of Grains for
Thioben- zothiazole-Containing Residues. Unpublished study received on
unknown date under 2F1264; CDL:097967-A.

00138078 Buckman Laboratories, Inc. (1975) Residue Data: Busan 30: Sugar
Cane. Unpublished study received Nov 12, 1976 under 7F1885;
CDL:097566-B.

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