Russell Wasem 

Chemical Review Manager 

EPA Pesticide Re-Evaluation Division 

One Potomac Yard 

2777 S. Crystal Drive 

Arlington, VA 22202 

TM/MBC Task Force 

c/o Nisso America Inc. 

88 Pine Street, 14th Floor 

New York, NY 10005 

June 10, 2014 

RE: Thiophanate-methyl and Carbendazim Registration Review (Case 2680) 

Comments to Docket ID No. EPA-HQ-OPP-2014-0004 

Dear Mr. Wasem: 

The Thiophanate-Methyl and Carbendazim Task Force (TM/MBC Task Force) is hereby providing 

comments to the public docket opened for the Registration Review ofthiophanate-methyl and 

carbendazim. The TM/MBC Task Force is composed of the following registrant companies: 

Adama USA, Gowan Company, Nippon Soda Co., Ltd., Nufarm Americas, Inc., and Troy Corporation. 

The TPM/MBC Task Force appreciates the opportunity to review and provide comments on EPA's 

preliminary work plan and anticipated data requirements for thiophanate-methyl (TM) and carbendazim 

(MBC). These comments primarily focus on the Environmental Fate and Effects Division's (EFED) and 

the Health Effects Division's (HED) anticipated data requirements for TM and MBC, and are offered in 

the spirit of making the best use of both EPA's and the registrants resources for the registration review 

of TM and MBC. 

The purpose of this letter is to provide additional information to the EPA with respect to the anticipated 

data needs outlined in the Preliminary Work Plan and its supporting documents from BEAD, EFED, and 

HED. 

In EPA's preliminary work plan and EFED's Preliminary Problem Formulation document, EFED has listed a 

number of anticipated data requirements for TM and MBC. As a general comment, a number of the 

proposed environmental fate data requirements are for repeat studies for which acceptable studies 

have already been submitted (see Table 8 in the EFED Preliminary Problem Formulation document). 

Repeating these studies is unlikely to result in any significant new data, or provide any substantial new 

information concerning the environmental fate properties of TM or MBC. Except for a general 

observation that a number of the environmental fate studies are old, for many of these repeat studies, 

EFED has not provided a rationale for why it believes new studies are necessary. The TM/MBC Task 

Force believes that in order to fully appreciate the shortcomings of the existing data (and thereby 
prevent the same situation from occurring should a study be repeated), the Agency should release the 

Data Evaluation Records (DERs) for the individual studies in question. 

Regarding Anticipated Data Needs as Outlined in the Preliminary Work Plan for Thiophanate-methyl 

Anticipated Environmental Fate Data Needs for TM 

EFED's proposed data requirements for TM include batch equilibrium testing, hydrolysis testing, aerobic 

soil metabolism, aerobic aquatic metabolism, anaerobic aquatic metabolism, and an environmental 

chemistry method and associated ILV for water. 

•Batch Equilibrium Adsorption/Desorption (835.1230) 

As mentioned in the EPA/EFED internal memorandum B. Montegue eta/ to R. Wasem eta/ 

dated March 18, 2014 (DP Barcodes D413007 and D480778) on page 36, a previously submitted study 

(MRID 42351001; Shiotani, H. (1992) Thiophanate-methyl Batch Equilibrum (Adsorption/Desorption on 

Soild): Lab Project Number: NISSO EC-362. Unpublished study prepared by Nippon Soda Co., Ltd., Envir. 

Tox. Lab. 106 p.) may address this anticipated data need. EPA indicated that this study is currently 

under review. The TM/MBC Task Force believes this study satisfies the batch equilibrium data 

requirement, and that no further testing is necessary. 

• Hydrolysis (835.2120) 

In the EPA/EFED internal memorandum B. Montegue et alto R. Wasem et al dated March 18, 

2014 (DP Barcodes D413007 and D480778), the Agency states on page 35 that "Existing [hydrolysis] 

studies will be re-reviewed." EPA indicated that this hydrolysis study is also currently under review. The 

TM/MBC Task Force believes that this study adequately satisfies the data requirement, and that no 

further testing is necessary. 

•Aerobic Soil Metabolism (835.4100) 

The TM/MBC Task Force would like to point out an inconsistency associated with this 

anticipated data need. The Preliminary Work Plan identifies the anticipated data need for an aerobic 

soil metabolism study; however, in Table 8 on page 37 of the EPA/EFED internal memorandum B. 

Montegue et alto R. Wasem et al dated March 18, 2014 (DP Barcodes D413007 and D480778), the 

Agency states than an existing study (MRID 00106085) is "acceptable" and that "Due to the rapid 

transformation [of TM] to MBC (half-life< 1 day in all 3 soils) study may meet requirements for MBC as 

well." EFED proposed requesting additional studies on three soils with specific pH values (<6.0, <6.3, 

and> 7.5). Acceptable aerobic soil metabolism data are already available for TM on three soils, and 

EFED has not explained why it is requesting additional aerobic soil metabolism data as the results of 

these three studies are consistent. 

While EFED has hypothesized that TM is more stable in acidic soils, this does not explain EFED's 

request for testing in a soil with a pH <6.0, and in another soil with a pH <6.3; or EFED's request for 

testing in a soil with a pH >7.5, particularly for TM, for which all the available data indicate degrades 

very rapidly (DT50 <=1 day). This rationale concerning TM being more stable under acidic conditions 

than basic conditions is more applicable to abiotic degradation than microbially-mediated degradation, 

and therefore it is not clear how this hypothesis concerning the effect of soil pH is relevant to the 

microbially-mediated degradation that occurs in aerobic soil metabolism testing. 
•Aerobic Aquatic Metabolism (835.4200) 

Similarly with the aerobic soil metabolism, the Preliminary Work Plan mentions an anticipated 

data need for this study but the March 18, 2014 EFED internal memorandum's Table 8 on page 37 

doesn't reflect this as the existing study (MRID 45621401) is considered "supplemental" but no 

additional data were deemed necessary. 

EPA is proposing aerobic aquatic metabolism testing in three systems; however, the guidelines 

only require aerobic aquatic metabolism testing in two systems. EFED has not provided a rationale as to 

why it is proposing to request aerobic aquatic metabolism testing in three separate systems. 

EFED has not provided a clear rationale as to why it is anticipating a need for aerobic aquatic 

metabolism testing in three separate systems. EFED is suggesting testing with soils/sediments of pHs 

<6.0, <6.3, and >7.5). EFED has not provided a rationale for these selected pHs, particularly the request 

for testing soils/sediments with pHs of such a narrow range (i.e., <6.0 and <6.3). These are the same pH 

values that EFED listed for its proposed aerobic soil metabolism testing, and it is not clear whether or 

how this request concerning pH values is applicable to the proposed request for aerobic aquatic 

metabolism testing. EFED's hypothesis that TM is more stable under acidic conditions than basic 

conditions is more applicable to abiotic degradation than the microbially-mediated degradation that is 

the focus of aerobic metabolism testing. Even if this hypothesis is accurate, it does not explain EFED's 

request for testing two acidic pH values. 

An acceptable study (classified as "supplemental") for two systems (a river water system and a 

pond water system) is available for TM, so the anticipated need for additional testing is indistinct. The 

TM/MBC Task Force would benefit from receipt of the DER for the existing study to clarify why it was 

classified as supplemental and why EFED believes this testing on two aerobic aquatic systems needs to 

be repeated. 

•Anaerobic Aquatic Metabolism (835.4300) 

Table 8 on Page 37 of the EFED's March 18, 2014 internal memorandum states that the existing 

anaerobic aquatic metabolism study with TM (MRID 40061501) is "acceptable." This is inconsistent with 

the Preliminary Work Plan's list of anticipated data needs. The data referenced in the Preliminary 

Problem Formulation document indicate that TM degrades very rapidly (half-life of 1 day) under 

anaerobic aquatic conditions. Since an acceptable study is available, EPA-EFED's rationale for requiring 

additional anaerobic aquatic metabolism testing in three systems is unclear. 

EPA is requesting anaerobic aquatic metabolism testing in three systems; however, the 

guidelines only require aerobic aquatic metabolism testing in two systems. EFED has not provided a 

rationale as to why it is proposing to request anaerobic aquatic metabolism testing in three separate 

systems. 

As with its request for aerobic soil metabolism testing and aerobic aquatic metabolism testing, 

EFED is requesting testing with soils/sediments of pHs <6.0, <6.3, and >7.5). EFED has not provided a 

rationale for these selected pHs, particularly the request for testing soils/sediments with pHs of <6.0 and 

<6.3. These are the same pH values that EFED listed for its proposed aerobic soil metabolism testing, 

and it is not clear whether or how this request concerning pH values is applicable to the proposed 

request for anaerobic aquatic metabolism testing. EFED's hypothesis that TM is more stable under 

acidic conditions than basic conditions is more applicable to abiotic degradation than the microbially-
mediated degradation that is the focus of anaerobic metabolism testing. Even if this hypothesis is 

accurate, it does not explain EFED's request for testing a two acidic pH values. 

•Environmental Chemistry Methods and Associated ILVs for Water (835.6200) 

An LC-MS/MS analytical method and validation report for quantitation of thiophanate-methyl 

(and carbendazim) in drinking water, ground water, and surface water is available for submission to the 

Agency. The Limit of Quantitation (LOQ) of the method for both analytes is 0.05 ~g/liter. The Task 

Force intends to submit this method to fulfill the Agency's request for an updated environmental 

chemistry method for TM in water. 

Anticipated Ecological Effects Data Needs for TM 

EFED's proposed data requirements for TM include seedling emergence and vegetative vigor studies as 

well as honey· bee acute oral and larval toxicity studies. 

•Terrestrial Plant Toxicity, Seedling Emergence (850.4100) 

Existing studies conducted at up to 1.41b ai/A are acceptable and reflect the maximum use rate 

on agricultural crops. Available data indicate no adverse effects on non-target terrestrial plants at the 

maximum agricultural use rate of 1.41b a. i./A. However, application rates on golf course tees and 

greens are higher (up to 8.161b a.i./A) while rates on fairways range up to 5.45lb a.i./A. Therefore the 

TM/MBC Task Force will consider the conduct of the study relative to rate adjustments (if any) on turf. 

•Terrestrial Plant Toxicity, Vegetative Vigor (850.4150) 

Existing studies conducted at up to 1.4 lb ai/ A are acceptable and reflect the maximum use rate 

on agricultural crops. Available data indicate no adverse effects on non-target terrestrial plants at the 

maximum agricultural use rate of 1.41b a .i./A. However, application rates on golf course tees and 

greens are higher (up to 8.16 lb a.i./A) while rates on fairways range up to 5.45 lb a.i./A. Therefore the 

TM/MBC Task Force will consider the conduct of the study relative to rate adjustments (if any) on turf. 

•Honey Bee Acute Oral Toxicity (OECD 213) 

A honeybee acute oral toxicity study (Nippon Soda Co., Ltd.; RD-1131) conducted under GLP and 

the applicable OECD guidelines in 2005 is available and shows the 48 hour acute oral LD50 value is> 114 

~g a. i./bee. These results indicate that TM is practically non-toxic to honeybees on an acute oral basis. 

The contact toxicity to honey bees was also determined in the study and was found to be > 100 ~g 

a.i./bee. The TM/MBC Task Force intends to submit this study to address the acute oral toxicity testing 

with honeybees anticipated data need. 

•Honey Bee Larval Toxicity (OECD 237) 

Both the acute contact and acute oral toxicity of TM are >100 ~g/bee therefore the TM/MBC 

Task Force questions the need for a honeybee larval toxicity study. EPA has not provided a rationale for 

needing data on larval toxicity given that TM is practically non-toxic to honeybees on both an acute 

contact and acute oral basis. These two studies are sufficient to evaluate the toxicity of TM to both adult 

and larval honeybees. Therefore, the TM/MBC Task Force requests that this anticipated data need be 

held in reserve until EPA has reviewed the acute oral toxicity study on honeybees. 
Anticipated Toxicology Data Needs for TM 

HE D's proposed data requirements for TM include a subchronic inhalation study and a developmental 

thyroid study. 

•Subchronic Inhalation Study 

Based on discussion with EPA during a meeting held on May 7, 2014, a 28-day inhalation study is 

acceptable in lieu of a 90-day inhalation study to fulfill this data requirement. In the meeting the Agency 

mentioned the need to include evaluation of thyroid effects and therefore the TM/MBC Task Force plans 

on submitting a protocol for EPA review prior to initiating any study ofthis type. 

•Developmental Thyroid Assay 

The TM/MBC Task Force recommends that the requirement for developmental thyroid assay 

data be placed on reserve until the results of the on-going 2-Generation Modified Rat Reproduction 

Study with Carbendazim are submitted and reviewed by the Agency. The on-going study includes an 

assessment of thyroid parameters and is scheduled for submission in September 2014. 

The following thyroid related parameters were assessed in the ongoing F1-extended two 

generation reproductive toxicity study of carbendazim {MBC): thyroid hormone assessment for multiple 

life stages: P adults (male and female, T4 and TSH); F1 PND 4 pups (pooled samples, T4 and TSH); F1 

PND 23 pups (male and female T4 and TSH); F1 adults (male and female T3, T4 and TSH, including from 

females at the end of gestation (Cohort 1A) and T4 and TSH at the end of lactation (Cohort 1B)); and F2 

PND 23 pups (male and female T4 and TSH). Thyroid weights were taken for all groups except PND 4 

pups. Thyroid histopathology, including subjective semi-quantitative scoring for follicular cell height and 

colloid area was performed for P adults, F1 cohort 3 PND 23 weanlings, F1 Cohort 1B adult males and 

adult females, F2 PND 23 weanlings and a subset of F2 female weanlings held to PND 45. As some 

developmental neurotoxicity parameters may be affected by changes in thyroid hormone levels, it is 

also relevant that Cohort 2 {F1) of the MBC F1-extended two generation reproductive toxicity study 

evaluated potential developmental neurotoxicity, including Functional Observational Battery, motor 

activity, and auditory startle in adults; and neuropathology of perfused pups and adults (including 

staining for myelin deposition) and brain morphometry. Given the rapid breakdown of thiophanate 

methyl to MBC, and the extensive thyroid and DNT data recently developed for MBC, we consider the 

Agency should hold the data requirement for a comparative thyroid evaluation ofthiophanate methyl in 

reserve, pending review and evaluation of the MBC F1-extended two generation reproductive toxicity 

study. 

Regarding Anticipated Data Needs as Outlined in the Preliminary Work Plan for Carbendazim (MBC) 

Anticipated Environmental Fate Data Needs for MBC 

EFED's proposed data requirements for MBC include batch equilibrium testing, hydrolysis testing, 

aerobic soil metabolism, aerobic aquatic metabolism, anaerobic aquatic metabolism, an environmental 

chemistry method and associated ILV for soil and water, and leaching studies with various treated 

matrices. 

•Batch Equilibrium Adsorption/Desorption {835.1230) 

As with thiophanate-methyl mentioned earlier, a previously submitted study (MRID 42351001; 

Shiotani, H. {1992) Thiophanate-methyi--Batch Equilibrum (Adsorption/Desorption on Soild): Lab Project 
Number: NISSO EC-362. Unpublished study prepared by Nippon Soda Co., Ltd., Envir. Tax. Lab. 106 p.) 

may address this anticipated data need. Table 8, page 38 in EFEO's March 18, 2014 internal 

memorandum also states that MRIO 42351001 is "acceptable" and no further data are needed. The 

TM/MBC Task Force believes the currently available study satisfies the batch equilibrium data 

requirement, and that no further testing is necessary. 

•Hydrolysis (835.2120) 

On page 35 of the EFED internal memorandum dated March 18, 2014, the Agency states that 

existing hydrolysis data will be "re-reviewed." EPA indicated that the currently available hydrolysis 

study is under review. The TM/MBC Task Force believes that the currently available study adequately 

satisfies the data requirement, and that no further testing is necessary. 

In addition to conducting a hydrolysis study at a standard temperature of 20 or 25°C, EPA also 

indicated that it has an anticipated data need for a non-guideline hydrolysis study conducted at 35°C. 

EPA has not provided a rationale for requesting this additional hydrolysis testing, nor, except for a vague 

reference to the PRZM-GW model, has EPA indicated how it intends to use these data. Model inputs for 

hydrolysis typically include hydrolysis rates at three different pHs (4-5, 7, and 9), but do not include 

hydrolysis rates at different temperatures. Since 35°( is not an environmentally relevant temperature, 

particularly for groundwater, the TM/MBC Task Force sees little regulatory need for conducting an 

additional, high temperature hydrolysis study. 

•Aerobic Soil Metabolism (835.4100) 

The Preliminary Problem Formulation indicates that an acceptable study conducted with 

benomyl is available and that no additional data are required. According to the information provided in 

the Preliminary Problem Formulation, in this study, benomyl was rapidly converted to MBC, and the 

degradation of MBC was clear in this study. Therefore, it is not clear why EPA is requesting additional 

aerobic soil metabolism data. 

The EPA internal memorandum B. Montegue eta/ to R. Wassem eta/ dated March 18, 2014 (OP 

Barcodes 0413007 and 0480778) on page 5 states that, "In the environment, TM [thiophanate-methyl] 

is expected to degrade rapidly to its primary degradate methyl2-benzimidazolylcarbamate (MBC)" and 

that " ... the half-life for conversion from TM to MBC may be from less than one day to several days by 

various environmental pathways ... " The document continues on page 10-11 with, "Rapid degradation [of 

TM] to MBC is expected based on the short half-live observed in aerobic soil and anaerobic aquatic 

systems via biotic and abiotic processes" and that "No evidence has been presented to refute this 

assumption that rapid conversion to MBC will occur from TM applied to soils or transported to water 

bodies." Also on page 37 of the March 18, 2014 EFED internal memorandum, Table 8 states that no 

further aerobic soil metabolism data are necessary for carbendazim since an MBC half-life in soil was 

calculated based on an acceptable benomyl study (MRIO 41255801). Based on this information, and 

considering the well-studied rapid degradation of thiophanate methyl (and benomyl) to carbendazim 

the TM/MBC Task Force proposes the Agency can rely on TM and benomyl aerobic soil metabolism data 

to support carbendazim. 

•Aerobic Aquatic Metabolism (835.4200) 

Table 8, page 37 in the EFEO internal memorandum dated March 18, 2014 states that an 

"acceptable" study exists (MRIO 41291501). Although the study was conducted with benomyl, the 

compound rapidly degrades to carbendazim (as does thiophanate-methyl) and a MBC decline rate was 

calculated. 
EPA is requesting repeat aerobic aquatic metabolism testing in three systems. However, the 

guidelines only require aerobic aquatic metabolism testing in two water-sediment systems. EFED has 

not provided a rationale as to why it is proposing to request repeat aerobic aquatic metabolism testing 

in three separate systems, particularly since an acceptable study on MBC is already available. 

The Preliminary Problem Formulation in the docket indicates an acceptable aerobic aquatic 

study, conducted with benomyl, is already available for MBC. Based on information provided in the 

Preliminary Problem Formulation document, benomyl was rapidly converted to MBC (in less than one 

day), and the metabolism of MBC was followed in this study, with reported half-lives of 23 and 61 days; 

EFED has already calculated an upper goth percentile confidence limit on the mean of 100 days using 

these data. Therefore, it is unclear why EPA is requesting additional data using three test systems. EPA 

has also specified that it is requesting testing in one system with a pH <6.0, one system with a pH <6.3, 

and one system with a pH >7.5. However, EPA has not explained its rationale for requesting testing with 

water-sediment systems with these specific pH values (other than indicating that MBC expected to be 

more stable at acidic pHs). However, this rationale relates more to abiotic degradation than microbiallymediated degradation. However, even if MBC is more stable at acidic pH values, EPA has not explained 

its rationale for testing with systems with pH values of <6.0 and <6.3. 

•Anaerobic Aquatic Metabolism (835.4300) 

As above, Table 8 page 37 in the EFED internal memorandum dated March 18, 2014, states that 

existing anaerobic aquatic metabolism data (MRID 41137701) is acceptable and that although the study 

was conducted with benomyl, the compound rapidly degrades to carbendazim (as does thiophanatemethyl) and a MBC decline rate was calculated. 

EPA is requesting repeat anaerobic aquatic metabolism testing in three systems. However, the 

guidelines only require anaerobic aquatic metabolism testing in two water-sediment systems. EFED has 

not provided a rationale as to why it is proposing to request repeat anaerobic aquatic metabolism 

testing in three separate systems, particularly since an acceptable study on MBC is already available. 

The Preliminary Problem Formulation indicates an acceptable anaerobic aquatic metabolism 

study, conducted with benomyl, is already available for MBC. Based on information provided in the 

document, benomyl was rapidly converted to MBC, and the metabolism of MBC was followed in this 

study. The results of this study indicate that MBC is essentially stable under anaerobic aquatic 

conditions. Therefore, it is unclear why EPA is requesting additional data using three test systems, 

particularly since the updated environmental fate testing guidelines only require testing in two watersediment systems. Since MBC was stable in the available study under anaerobic aquatic conditions, 

there is little point in conducting additional anaerobic aquatic metabolism testing. EPA has also 

specified that it is requesting testing in one system with a pH <6.0, one system with a pH <6.3, and one 

system with a pH >7.5. However, EPA has not explained its rationale for requesting anaerobic aquatic 

metabolism testing with water-sediment systems with these specific pH values (other than MBC 

expected to be more stable at acidic pHs). In particular, EPA has not explained the rationale for testing 

with systems with pH values of <6.0 and <6.3. Even if EFED's hypothesis about MBC being more stable 

under acidic pH values is correct, this hypothesis is more applicable to abiotic degradation that the 

microbially-mediated degradation that is the focus of anaerobic metabolism testing. 
•Environmental Chemistry Methods and Associated ILVs for Soil and Water (83S.6200) 

EPA indicated that it plans on requesting environmental chemistry methods and ILVs for soil and 

water for MBC. An LC-MS/MS analytical method and validation report for quantitation of carbendazim 

(and thiophanate-methyl) in drinking water, ground water, and surface water is available for submission 

to the Agency. The Limit of Quantitation (LOQ) of the method for both analytes is O.OS 1-lg/liter. This 

method satisfies the data requirement for an environmental chemistry method in water. The TM/MBC 

Task Force intends to submit this method and validation to fulfill the Agency's request for an updated 

environmental chemistry method for water. 

A validated QuEChERS method for carbendazim (and thiophanate-methyl) in soil is also 

available. The LOQ of the LC-MS/MS method is 0.01 mg/kg. This method satisfies the data requirement 

for an environmental chemistry method in soil. The Task Force intends to submit this method and 

validation to fulfill the Agency's request for an updated environmental chemistry method for MBC in 

soil. 

• Leaching Studies for the Following Use Scenarios: Exterior Painted Surfaces/Wood Protective 

Stains/Roof Coatings; Treated Textiles (Non-Guideline) 

The sole registrant of anti-microbial uses indicates data are available to address the anticipated 

data need for exterior painted surfaces/wood protective stains/roof coatings. The registrant is currently 

evaluating the market for MBC in the textile industry and the anticipated data need for leaching studies 

in treated textiles should be placed on reserve while the use pattern is clearly defined. 

Anticipated Ecological Effects Data Needs for MBC 

EFED's proposed data requirements for MBC include aquatic plant toxicity, honey bee acute oral and 

larval toxicity, and chronic whole sediment testing with aquatic invertebrates. 

•Aquatic Plant Toxicity (8S0.4400, 4SOO, 4SSO) 

A full battery of aquatic plant testing is available for TM. Results of these studies indicate that 

ECSO values and NOECs for algae and a representative aquatic vascular plant (Lemna) are well above (by 

more than an order of magnitude) the aquatic EECs for both TM and MBC. Therefore, the Task Force 

sees little regulatory value in conducting a full battery of non-target aquatic plant testing for MBC. The 

TM/MBC Task Force proposes to conduct testing with a representative aquatic vascular plant (Lemna 

gibba) and the most sensitive algal species tested with TM (Navicula pellicosa). The TM/MBC Task Force 

requests that testing with additional algal species be placed on reserve pending the results of these 

initial tests. If the results of the initial tests with MBC are consistent with the available results for 

testing with TM, the TM/MBC Task Force sees little point in conducting additional non-target aquatic 

plant testing with MBC. 

• Honey Bee Acute Oral Toxicity (OECD 213) 

An acute contact toxicity of carbendazim to honey bee (MRID 001S469S) resulted in a 

"practically non-toxic" classification (i.e., > SO 1-lg ai/bee). Based on these data, along with considering 

that thiophanate-methyl has an acute contact toxicity to honey bee of >100 1-lg ai/bee ("practically nontoxic") (MRID 400S3209) and an acute oral toxicity to bees of >114 1-lg ai/bee (practically non-toxic, see 

TM section on honey bee studies above), it can be inferred that the acute oral toxicity of MBC to honey 

bees would be in the area of ~SO j..lg ai/bee and therefore classified as practically non-toxic. Considering 

the available data on MBC and TM overall, there is little regulatory value in conducting an acute oral 

toxicity study with MBC on bees. The TM/MBC Task Force has not seen data that support EPA's 
contention that acute contact toxicity is not always a reliable indicator of acute oral toxicity; however, in 

the case of TM, the acute contact and acute oral toxicity data are consistent, and indicate very low 

toxicity to bees, and there is no reason to suspect that the low toxicity exhibited to bees by MBC in the 

acute contact study would not also be exhibited in an acute oral toxicity study. 

• Honey Bee Larval Toxicity (OECD 237) 

As with TM, if a compound is considered practically non-toxic to honey bees exposed via contact 

and oral routes, the information is sufficient to predict similarly low toxicity to bee larvae. It is not clear 

why EPA believes that it needs both a honeybee larval toxicity study and an acute oral toxicity study 

with MBC when all the available data indicate that both TM and MBC display low toxicity to bees. At 

this time, it seems appropriate to place this study on reserve until the available data on MBC and TM are 

reviewed. In particular, if an acute oral honey bee toxicity study is conducted with MBC and is 

consistent with available data indicating low toxicity of MBC and TM to bees, as expected, then the 

TM/MBC Task Force sees little regulatory value in generating data on the toxicity of MBC to larval bees. 

• Whole Sediment Chronic Toxicity Test for Aquatic Invertebrates (Non-Guideline) 

The EFED Preliminary Problem Formulation document indicates that EPA anticipates the need 

for sediment toxicity testing on both freshwater and marine species (guidelines 850.1735 and 

850.1740). EPA has not provided a rationale or justification for requesting sediment toxicity testing on 

both freshwater and marine organism, so it is not clear why the Agency anticipates this data need. The 

available data on freshwater and estuarine-marine invertebrates indicates that representative 

freshwater invertebrate species are more sensitive to MBC than representative estuarine-marine 

invertebrates. Therefore, should the Agency require sediment studies, the TM/MBC Task Force 

proposes to initially conduct sediment toxicity testing with a representative freshwater species and 

placing the requirement for testing with estuarine-marine species on reserve pending the results of 

testing with a freshwater species. If the results of sediment toxicity testing with a representative 

freshwater species indicates that the toxicity of MBC to sediment-dwelling organisms is less than the 

toxicity of MBC to representative freshwater pelagic invertebrates that have already been tested (e.g., 

daphnids), then the TM/MBC Task Force sees little point in conducting sediment toxicity testing with an 

estuarine-marine species given that MBC has already been shown to be less toxic to representative 

estuarine-marine invertebrates than to representative freshwater invertebrates. 

Anticipated Toxicology and Exposure Data Needs for MBC 

HED's proposed data requirements for MBC include an immuntoxicity study and various exposure 

studies depending upon the use pattern. 

•lmmunotoxicity (870.7800) 

An extended one generation rat reproduction study with MBC is currently underway. The 

following immunotoxicity parameters are measured in the study: white blood cell counts and spleen 

and thymus weights and histopathology. The anticipated data need for an immunotoxicity study with 

MBC should be placed on hold pending the review and evaluation of the rat reproduction study. 

•Occupational Handler Dermal and Inhalation Exposure Applying Paint/Stain (Airless Sprayer, Low 

Pressure Handwand and Brush/Roller) (875.1200/875.1400) 

The registrant intends to supply this information via its membership in the American Chemistry 

Council's (ACC) Antimicrobial Exposure Assessment Task Force II (AEATF II). 
• Occupational Dermal and Inhalation for Pouring Liquid and/or Solid Material Preservatives 

Formulations (Paint/Stains, Slurries) (875.1200/875.1400) 

The registrant intends to supply this information via its membership in the American Chemistry 

Council's (ACC) Antimicrobial Exposure Assessment Task Force II (AEATF II). 

• Residential Handler Dermal and Inhalation Exposure Applying Paint/Stain (Airless Sprayer and 

Brush/Roller) (875.1200/875.1400) 

The registrant intends to supply this information via its membership in the American Chemistry 

Council's (ACC) Antimicrobial Exposure Assessment Task Force II (AEATF II). 

• Product Use for Applying Paints/Stains (875.1700) 

The registrant intends to supply this information via its membership in the American Chemistry 

Council's (ACC) Antimicrobial Exposure Assessment Task Force II (AEATF II). 

• Product Use Information for Pouring Liquid/Solid Material Preservative Formulation (875.1700) 

The registrant intends to supply this information via its membership in the American Chemistry 

Council's (ACC) Antimicrobial Exposure Assessment Task Force II (AEATF II). 

• Indoor Surface Residue Dissipation for Plastic Toys and Textiles (875.2300) 

The registrant is reassessing the role of MBC in the textile market and intends to limit the use of 

MBC products in plastic articles which are not for toys. This anticipated data need should be placed on 

reserve while the use pattern is clearly defined. 

Regarding Benefits ofThiophanate-methyl and Carbendazim 

Thiophanate-methyl belongs to the benzimidazole class of chemistry (FRAC Code 1) and is the only 

fungicide in the class currently registered for use in the United States. As such, it is a valuable tool in 

Integrated Pest Management programs where fungicides with different modes of action are 

recommended to reduce the potential for disease resistance. There is a continued need for the 

compound in crop production, particularly minor use crops, as noted by various projects undertaken by 

IR-4. 

Carbendazim is one ofthe few broad spectrum fungicides available for use in the paints and coatings 

industry. At this point in time, water-based dispersion concentrates with carbendazim are the leading 

products used by paint and coating manufacturers. This is also the case for adhesives and 

concrete/stucco mixtures. Formulations based on dispersion technology are easily incorporated into 

various manufacturing processes; and, because they are water-based, avoid additional loading of 

volatile organic compounds (VOC's) into the air. Carbendazim is rarely used as the sole active ingredient 

and typically acts with other fungicides to provide a wide spectrum of activity against fungal attack in 

various matrices. Where currently approved fungicides have specific "gaps" in microbial control, the 

addition of carbendazim reduces overall product use rates and provides all encompassing fungal control.. 

Lastly, the TM/MBC Task Force is particularly interested in receiving the Data Evaluation Records (DERs) 

for the existing reviewed studies that are now included in the list of anticipated data needs and would 

like the opportunity to meet with the EPA to fully describe the use patterns associated with 

thiophanate-methyl and carbendazim and address any questions the Agency may have in this area. 
Thank you for this opportunity to provide comments on the Preliminary Work Plan. Please feel free to 

contact me should you have any questions or comments on our proposals. 

cc: TM/MBC Task Force 

il~ On the behalf of: 

John J. Wrubel 

Chairman 

TM/MBC Task Force