1 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

Date: May 6, 2014

PC Code: 084701 

MEMORANDUM DP Barcode: 417576 

SUBJECT: Registration Review: Draft Problem Formulation for Environmental Fate, 

Ecological Risk, Endangered Species, and Human Health Drinking Water 

Exposure Assessments for Etridiazole 

FROM: Karen Milians, Ph.D., Chemist 

 Catherine Aubee, Biologist 

Environmental Risk Branch IV 

Environmental Fate and Effects Division (7507P) 

REVIEWED 

BY: Jim Carleton, Ph.D., Senior Scientist 

 Thomas Steeger, Ph.D., Senior Advisor 

Environmental Risk Branch IV 

Environmental Fate and Effects Division (7507P) 

THROUGH: Sarah Winfield, Acting Branch Chief 

Environmental Risk Branch IV 

 Environmental Fate and Effects Division (7507P) 

 

TO: Margaret Hathaway, Chemical Review Manager 

 Tom Myers, Team Leader 

 Risk Management and Implementation Branch II 

Pesticide Re-Evaluation Division (7508P) 

1. Executive summary 

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem 

formulation for the ecological risk, environmental fate, endangered species, and drinking water 

assessments to be conducted as part of the registration review of the fungicide etridiazole (also 

referred as Terrazole®, CAS No: 2593-15-9). The problem formulation describes the methods to 

be used during the completion of drinking water and ecological risk assessments in support of 

registration review and provides an overview of the environmental fate, ecological effects, and 
2 

potential risks associated with the use of etridiazole. It describes uncertainties which may be 

encountered in the risk assessment and identifies additional studies and other information that 

would be beneficial to its conduct. Below is a summary of data needs and uncertainties. 

 The following additional studies are recommended to support the risk assessment for 

etridiazole (40 CFR Part 158.1300): 

o Environmental Chemistry Methods (ECM) for Soil and Water and Associated 

Independent Laboratory Validation (ILV), OCSPP Guideline 850.6100 is needed 

to support field dissipation studies. 

o Aerobic aquatic metabolism study, OCSPP Guideline 835.4300. 

o Anaerobic aquatic metabolism study, OCSPP Guideline 835.4400. 

 The revised ecological risk assessment (DP Barcode 265767+, 2000) for the Reregistration Eligibility Decision (RED) identified ecological data gaps for etridiazole 

degradates. The following studies were neither submitted nor waived and remain as data 

gaps: 

o Acute toxicity to estuarine/marine fish using the degradate 3-DCMT (Guideline 72-

3, OCSPP Guideline 850.10751

) 

o Acute toxicity to freshwater fish using the degradate 3-Carb-T (Guideline 72-1, 

OCSPP Guideline 850.1075) 

o Acute toxicity to freshwater invertebrates using the degradate 3-Carb-T (Guideline 

72-2, OCSPP Guideline 850.10102

) 

 The following additional studies are recommended to support the risk assessment for 

etridiazole, based on the most current ecological data requirements (40 CFR Part 158.6303

et seq.) and risk assessment guidance: 

o Acute oral toxicity to passerine birds using etridiazole technical grade active 

ingredient (TGAI) (OCSPP Guideline 850.21004

) 

o Acute contact toxicity to adult honey bee using TGAI (OCSPP Guideline 

850.30205

) 

o Acute oral toxicity to adult honey bee using TGAI (e.g., OECD 2136

) 

o Larval toxicity to honey bee using TGAI (e.g., OECD 2377, requires protocol 

submission) 

 

1

 USEPA. 1996. Ecological Effects Test Guidelines OPPTS 850.1075 Fish Acute Toxicity Test, Freshwater and Marine. EPA 712-C-96-118. 

April 1996. http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-

1075.pdf (last accessed 03/26/14). 2

 USEPA. 1996. Ecological Effects Test Guidelines OPPTS 850.1010. Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids. EPA 

712-C-96.114. April 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-1010.pdf (last 

accessed 03/26/14). 

3

 CFR. 2014. Title 40 (Protection of the Environment), Part 158 (Data Requirements for Pesticides) Subpart G (Ecological Effects) §158.630 

(Terrestrial and aquatic nontarget organism data requirements table). http://www.ecfr.gov/cgi-bin/textidx?SID=b89b30110740e33a25b44c51806f0f62&node=40:25.0.1.1.9.7.1.1&rgn=div8 (last accessed 03/26/14). 4

 USEPA. 2012. Ecological Effects Test Guidelines OCSPP 850.2100: Avian Acute Oral Toxicity Test. EPA 712-C-025 January 2012.

file:///C:/Users/tsteeger/Downloads/EPA-HQ-OPPT-2009-0154-0010%20(3).pdf (last accessed 03/26/14). 5

 USEPA. 2012. Ecological Effects Test Guidelines OCSPP 850.3020: Honey Bee Acute Contact Toxicity Test. EPA 712_C-019. January 

2012. file:///C:/Users/tsteeger/Downloads/EPA-HQ-OPPT-2009-0154-0016%20(12).pdf (last accessed 03/26/14). 6

 OECD. 1998. OECD Guidelines for the Testing of Chemicals. Honeybees, Acute Oral Toxicity Test. OECD/OCDE 213 Adopted: 21st

September 1998. http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1395850163&id=id&accname=guest&checksum=DA5C05C00A6B947E222C562C20D

9EDA1 (last accessed 03/26/14) 7

 OECD. 2013. OECD Guidelines for the Testing of Chemicals. Honey bee (Apis mellifera) larval toxicity test, single exposure. OECD/OCDE 

237 Adopted 26 July 2013. http://www.oecdilibrary.org/docserver/download/9713171e.pdf?expires=1395849980&id=id&accname=guest&checksum=486E98B9ADBE06C29723801743480

A3B (last accessed 03/26/14)
3 

o Freshwater fish full life cycle test using TGAI (OCSPP Guideline 850.15008

, 

requires protocol submission) 

o Fish early life stage test (estuarine/marine species) using TGAI (OCSPP Guideline 

850.14009

) 

o Mysid chronic toxicity test using TGAI (OCSPP Guideline 850.135010) 

o Terrestrial plants seedling emergence and seedling growth using an etridiazole 

typical end-use product (TEP) (OCSPP Guideline 850.410011) 

o Terrestrial plants vegetative vigor using TEP (OCSPP Guideline 850.415012) 

o Aquatic plant toxicity test using Lemna ssp. using TEP (OCSPP Guideline 

850.440013) 

Additionally, the mass of active ingredient (a.i.) per granule is needed to assess exposure and risk 

to terrestrial vertebrates from granular products. 

2. Introduction 

Etridiazole is a soil fungicide that belongs to the thiazole family. Etridiazole is used against a 

narrow range of plant pathogenic soil fungi (water mold species of the Fusarium, Pythium, 

Rhizoctonia, and Phytophthora genera of fungi). In addition, the chemical is also an inhibitor of 

soil nitrification and is applied to delay nitrification of ammonia and urea-based fertilizers by 

inhibiting the activity of bacteria in the Nitrosomonas genus (USEPA, 2000a). 

Etridiazole is formulated as emulsifiable concentrate, wettable powder, granular, and soluble 

concentrate with application methods that include: ground spray, aerial spray, soil in furrow 

treatment, broadcast, soil drench treatment, and chemigation. The maximum single application 

rate for etridiazole is on ornamentals at 26.1 pounds of active ingredient per acre (lbs a.i./A). 

EFED examined the most recent environmental fate and ecological risk assessments for the reregistration eligibility decision (RED) of etridiazole (USEPA, 2000a) in association with updated 

toxicity, exposure, and usage information to determine if additional data are needed to support 

Registration Review. In addition, EFED considered the latest Agency science policies and risk 

assessment methodologies. There have not been any new actions for etridiazole since publication 

of the RED in September, 2000. 

 

8

 USEPA. 1996. Ecological Effects Test Guidelines OPPTS 850.1500 Fish life cycle toxicity. EPA 712-C-96-122. April 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-1500.pdf (last 

accessed 03/26/14). 

9

 USEPA. 1996. Ecological Effects Test Guidelines OPPTS 850.1400 Fish Early-Life Stage Toxicity Test. EPA 712-C096-121. April 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-1400.pdf (last 

accessed 03/26/14). 

10 USEPA. 1996. Ecological Effects Test Guidelines OPPTS 850.1350 Mysid Chronic Toxicity Test. EPA 712-C-96-120. April 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-1350.pdf (last 

accessed 03.26.14).

11 USEPA. 2012. Ecological Effects Test Guideline OCSPP 850.4100: Seedling Emergence and Seedling Growth. EPA 712-C-012. January

2012. file:///C:/Users/tsteeger/Downloads/EPA-HQ-OPPT-2009-0154-0023%20(1).pdf (last accessed 03/26/14) 12 USEPA. 2012. Ecological Effects Test Guidelines OCSPP 850.4150: Vegetative Vigor. EPA 712-C-011. January 2012. 

file:///C:/Users/tsteeger/Downloads/EPA-HQ-OPPT-2009-0154-0024%20(2).pdf (last accessed 03/26/14) 13 USEPA. 2012. Ecological Effects Test Guidelines OCSPP 850.4400: Aquatic Plant Toxicity Test Using Lemna spp. EPA 712-C-008. January 

2012. file:///C:/Users/tsteeger/Downloads/EPA-HQ-OPPT-2009-0154-0027%20(1).pdf (last accessed 03/26/14). 
4 

3. Use Characterization 

Etridiazole is used as a soil-incorporated fungicide, and is currently registered for use on cotton, 

tobacco, tomato, turf (golf-course tees, greens and fairways), on ornamental plants, and 

commercial nurseries. Currently, etridiazole has a total of seventeen active labels. 

 

The current maximum single application rate is 26.1 lbs a.i./A for ornamentals (granular 

formulation, EPA Reg. No.: 58185-13); however, the maximum annual application is not specified 

for this use on the label and it is the soluble concentrate formulation (EPA Reg. No.: 400-575) that 

has the maximum annual application rate of 28 lbs a.i./A (14 lbs a.i./A x 2 applications) for the 

same use. 

A Screening Level Usage Analysis (SLUA) was prepared by Biological and Economical Analysis 

Division (BEAD) for etridiazole in 2014 that provides percent crop treated for cotton for which 

usage data was available. Use for cotton over the SLUA timeframe (1998-2011) accounted for 

l00% of the agricultural etridiazole usage. For the years 1998-2012, etridiazole annual agricultural 

usage averaged 23,000 pounds of active ingredient (a.i.) treating an average of 126,000 acres, for 

an overall average application rate of 0.1825 lbs a.i./acre. Use in terms of both pounds a.i. and total 

area treated peaked in 2000, and has been steadily declining until the most recent years for which 

data are available (Proprietary data, 1998-2012). 

This chemical's usage both in terms of total pounds and total area treated are in decline. BEAD 

information indicates 14,000 lbs etridiazole used on U.S. turf and ornamental uses for 2012 

(EPA Proprietary Data, 2012). 

The chemical profile produced by BEAD lists the use patterns of maximum exposures for the 

current uses of etridiazole. EFED will use application scenarios that result in maximum exposure 

scenarios for a given use for the risk assessment. 

4. Conclusions from Previous Risk Assessments 

The RED document for etridiazole (USEPA, 2000b) was issued in September 2000. Based on the 

RED analysis of the environmental fate, ecotoxicity, and registered uses of etridiazole, exposure 

to etridiazole resulting from the maximum application rate may cause chronic risk levels of 

concern (LOCs) to be exceeded for terrestrial and aquatic organisms. 

a. Ecological Risk Assessment 

 The major environmental fate conclusions presented in the RED were as follows: 

1. Etridiazole has properties and characteristics associated with chemicals detected in 

ground water. The use of this chemical in areas where soils are permeable, 

particularly where the water table is shallow, may result in ground-water 

contamination. 
5 

2. Etridiazole may contaminate drinking water when etridiazole reaches surface water 

through spray drift. Additionally, under some conditions, it may also have high 

potential for runoff into surface water for several weeks post-application. These 

include poorly draining or wet soils with readily visible slopes toward adjacent 

surface waters, frequently flooded areas, areas over-laying extremely shallow 

ground water, areas with in-field canals or ditches that drain to surface water, areas 

not separated from adjacent surface water with vegetated filter strips. 

Potential risk issues identified in the RED are briefly summarized in Table 1. The use of 

etridizaole on turf at the maximum labeled rate was associated with risk exceeding LOCs for most 

taxa for which toxicity data were available. The use on cotton was associated with chronic risk to 

birds. Seed treatment uses were assessed in the RED but have since been removed from the current 

list of active labels. 

Table 1. Summary of Potential Issues Identified for Etridiazole in Previous Assessments

Birds Mammal

s 

Terr. 

Plants 

Terr. 

Inverts Fish BCF Aquatic Inverts 

Aquatic 

Plants 

Groundwater 

Contamination 

Persistenc

e 

Degradates 

of Concern 

Yes Yesa No 

Data 

No 

Data Yes No Yesb Yes Possible Risk LowModeratec Yesd

Yes = at least one LOC has been exceeded in previous assessments; No = LOCs have not been exceeded in previous 

assessments. 

a Data gap for chronic toxicity to mammals. 

b RQs exceeded the LOC for acute risk to listed species only. 

c

 Moderately persistent in aquatic environment and non-persistent in terrestrial environment (Goring scale, 1975). 

d Pending the submission of additional data for 3-DCMT and 3-Carb-T. 

b. Drinking Water Exposure Assessments 

EFED conducted a risk assessment of etridiazole as part of the RED in 2000 for the uses on barley, 

beans, corn, cotton, peanuts, peas, sorghum, soybeans, safflower, wheat, horticultural nurseries, 

non-bearing coffee, and golf course fairways, tees and greens for parent only (USEPA, 2000b). 

The turf use was expected to pose the highest risk due to having the highest annual application rate 

(3.8 lb a.i./A x 2 applications/year, 10 day interval) for golf course and 3.8 lb a.i./A x 5 

applications/year for tees and greens, 5-10 days interval) and was therefore used to estimate the 

environmental concentrations (EECs) in surface as well as ground water. The EECs were 

calculated using GENEEC plus PRZM/EXAMS (surface water) and SCIGROW (ground water). 

For surface water, the acute (peak) value was 228.09 ppb (Tier I, turf) or 2.2277 ppb (Tier II, 

cotton), and chronic values were 0.146 ppb (Tier II, cotton scenario) and 0.05 ppb (Tier II cotton, 

overall mean). The ground water screening concentration was 0.926 ppb. The Tier I value from 

GENEEC represented the upper-bound estimate of the concentration that might be found in surface 

water, which was the worst case scenario (no turf scenario was available in 2000). Based on 5 

applications the EEC was 437 μg/L at 10-day intervals. The ground water reported was 0.93 μg/L. 
6 

c. Clean Water Act Programs 

Etridiazole is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act. No Total Maximum Daily Loads (TMDLs) or 

water quality criteria have been developed for etridiazole. 14

5. Environmental Fate and Transport 

Etridiazole is a mobile compound (FAO 2000) with low to moderate persistence (Goring et al. 

1975). These properties generally would raise concerns related to the potential for ground and/or 

surface water contamination. However, application rates (on tobacco and tomatoes) are sufficiently 

low that prior assessments have found the chemical to pose relatively low contamination hazard 

to such waters. Relatively rapid dissipation via volatilization may be expected for the low 

application rates for tobacco and tomatoes. Turf, nurseries and ornamental plant uses, however, 

present a different situation because the application rates are very high (ranging from 9.81 lb a.i./A 

to 28 lb a.i./A for these uses) and therefore are more likely to result in surface and/or ground water 

contamination. Once in the aqueous environment, etridiazole may persist for long periods of time 

due to its resistance to abiotic degradation (i.e., etridiazole is moderately persistent to hydrolysis 

and stable to aqueous photolysis). 

Table 2 summarizes the physico-chemical properties of etridiazole. Based on the chemical’s 

Henry’s Law Constant (3.08 x 10-5 atm· m 3

·mole -1), volatilization from water may or may not be 

significant depending on environmental conditions (e.g., depth of the water, temperature, wind 

speed and flow rate) (Thomas 1990). The chemical’s solubility in water is high (106 ppm) and the 

log octanol/water partition coefficient (Kow) is 2340, which indicates a potential to bioaccumulate. 

However, the BCF data suggest that the parent compound is being metabolized in fish and rapidly 

depurated. 

The primary route of dissipation of etridiazole is volatilization and to a lesser degree aerobic soil 

metabolism. Etridiazole is stable to hydrolysis and aqueous photolysis; however, it is susceptible 

to soil photolysis. In aerobic soils etridiazole declines slowly, following a biphasic pattern 

consistent with a chemical that readily volatilizes and undergoes slow aerobic degradation. In the 

organic volatiles traps etridiazole was 10% of the applied at day 1, 30.1% by day 14 and 49.9% of 

the applied at 180 days post-treatment. Terrestrial field dissipation studies show that etridiazole 

has low to moderate persistence (t1/2= 4-33 days, based on Goring et al. 1975) and appears to 

suggest substantial volatilization as evidence by low recoveries one day after application (although 

no air sampling was conducted). 

Etridiazole is expected to be moderately mobile in the environment, and is not expected to partition 

strongly to sediment Freundlich Kads values were 8.2 for the sandy loam soil (4.0% organic matter, 

o.m.), 8.2 for the clay soil (7.2% o.m.), 5.1 for the silt loam soil (2.7% o.m.), and 0.44 for the sand 

soil (0.16% o.m.); corresponding Koc values of 349, 195, 323 and 469 mL/g, respectively (FAO 

scale, 2000). Despite its overall persistence, under ideal conditions (e.g. when the compound is 

 

14 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 
7 

present in favorable light conditions) the compound may rapidly photodegrade in soil (t1/2=14.3 

day). 

Table 2. Chemical Properties and Environmental Fate Parameters of Etridiazole 

Parameter Value Description Reference 

Chemical Classification Thiadiazole 

Product 

Chemistry 

Molecular Formula C5H5Cl3N2OS 

PC Code 084701 

Chemical Name 

(IUPAC) 

ethyl 3-trichloromethyl-1,2,4-thiadiazol-5-

yl ether 

Chemical Name (CAS) 5-ethoxy-3-trichloromethyl-1,2,4-

thiadiazole

CAS Number 2593-15-9 

Pesticide Classification fungicide 

Physical/ 

chemical property 

data 

Molecular Weight 247.5 g/mol 

Water Solubility at 

20oC (ppm) 106 

Vapor pressure (25oC) 1.073 x 10-2 mmHg Volatile 

Henry's Law Constant 

at pH 7 3.08 x 10-5 atm· m 3

·mole -1 May volatilize 

Log Octanol/Water 

Partition coefficient 

(log Kow) 

2340 Potential to 

bioaccumulate 

Product 

Chemistry 

Persistence 

Hydrolysis 

t1⁄2 = 82 days at pH 5.1 

t1⁄2 = 83 days at pH 7.1 

t1⁄2 = 81 days at pH 8.9 

Moderately persistent Accession No. 

00001650 

Direct photolysis in 

water at pH 7 Stable Based on the absorption spectrum MRID 42872501 

Photolysis on soil t1⁄2 = 14.3 days on sandy loam Non-persistent MRID 43124301 

Aerobic soil 

metabolism t1/2 = 34 days Non-persistent MRID 43504301 

Anaerobic soil 

metabolism Not submitted 

Anaerobic Aquatic 

metabolism Invalid MRID 43504305 

Aerobic aquatic 

metabolism Not submitted 

Field Dissipation 

Terrestrial field 

dissipation 

t1/2= 8 days (sandy loam soil) in bare 

ground and wettable product formulation 

Non-persistent when 

applied in different 

formulations under 

MRID 44689602 
8 

Parameter Value Description Reference 

3-Carb-T in bare ground 

 t1/2= 16 days (loamy sand) emulsifiable 

concentrate formulation 

t1/2= 4 days (Montell clay) granules 

formulation 

diverse meteorological 

conditions at different 

locations MRID 44689603 

3-DCMT in bare ground 

t1/2= 33 days (sandy loam) and WP 

formulation and formulation wettable 

product formulation 

MRID 44689604 

Mobility 

Leaching and 

absorption/desorption 

Parent 

Koc and Kd in mL/g 

349 and 8.2, sandy loam 

195 and 8.2, clay 

469 and 0.44, sand 

 323 and 5.1, Silt loam 

Moderately Mobile MRID 43504302 

T-Carb Metabolite 

Koc and Kd in mL/g 

20 and 0.46, sandy loam 

13 and 0.55, clay 

16 and 0.01, sand 

 22 and 0.34, Silt loam 

Mobile MRID 43504303 

3-DCMT Metabolite 

Koc and Kd in mL/g 

118 and 2.8, sandy loam 

50 and 2.1, clay 

148 and 0.13, sand 

 128 and 2.0, Silt loam 

Mobile to Moderately 

Mobile MRID 43504304 

Fish Bioconcentration 

Bioconcentration in 

fish (BCF) 

94 X (muscle) 

328 X (non-edible tissue) 

193 X (fish) 

Not prone to 

bioaccumulate 

MRID 

43241401 

Laboratory Volatility 

Laboratory Volatility 

0.11-0.28 μg/cm2

 · hour at 6 hours 

0.04-0.16 μg/cm2

 · hour at 24 hours 

≤0.02 μg/cm2

 · hour at 120 through 336 

hours 

Volatility is 

proportional to soil 

moisture and relative 

humidity (mostly 

parent was detected) 

MRID 

43024101 

AR=Applied Radioactivity 

Classification of persistency was based on Goring scale, 1975. 

Mobility was described using FAO, 2000. 

Etridiazole’s dissipation from soil is presumably dependent upon volatilization, soil metabolism, 

leaching, and/or runoff. It may reach surface waters following rain events that produce runoff a 

few days to weeks after applications. Because etridiazole is moderately persistent to hydrolysis 

degradation it may persist in water bodies that have long residence times. 
9 

a. Transformation Products 

Two degradates of concern have been identified in laboratory studies and monitored in the field: 

3-dichloromethyl-5-ethoxy-1,2,4-thiadiazole (3-DCMT) and 5-ethoxy-1,2,4-thiadiazole-3-

carboxylic acid (3-Carb-T). In hydrolysis, photolysis in soil and aerobic soil, 3-Carb-T was found 

up to 72 %, 38% and 6.7% of the applied radioactivity, respectively. Only 7% of the applied 

formed as 3-DCMT in the aerobic soil metabolism study, however, because of the structure 

similarities with the parent molecule, 3–DCMT was included as degradate of concern. In field 

dissipation studies, 3-Carb-T was persistent, mobile (relative to the parent compound) and was 

detected in the 24-30 inch depth while the degradate 3-DCMT appeared to be persistent, but it did 

not leach substantially (was not detected below 6 inch depth at 123 days of treatment). However, 

in batch equilibrium studies both degradates had high mobility (refer to Table 2 for values). 

Representing lower percentages of the total applied radioactivity, the following degradates have 

been detected in some studies: 5-hydro-3-trichloro methyl-1,2,4-thiadiazole (5-hydroxyetridiazole or 5-OH-Terr), 5-ethoxy-monochloromethyl-1,2,4-thiadizole (3-monochloromethyletridiazole or 3-MCL-Terr) and oxalic acid. 

It is unlikely for the etridiazole parent molecule to partition into sediment. However, there is 

uncertainty regarding the potential for degradates of concern to form in other anaerobic 

environments. The submitted anaerobic aquatic metabolism study (MRID 43504305) was 

classified as invalid, due in part to uncertainty in the study conditions, but the data showed that 3-

DCMT formed up to 29% of applied. Without adequate data on anaerobic metabolism of 

etridiaozole, the Agency will be unable to quantitatively assess the potential exposure of nontarget 

organisms to etridiazole degradates of concern. Organisms may be exposed to degradates which 

form under anaerobic conditions if they inhabit anoxic or hypoxic environments, or if degradates 

formed under anaereobic conditions are distributed to aerobic environments. 
10 

Table 3. Etridiazole and Its Major Environmental Degradates 

Code Name/ Synonym Chemical Name Chemical Structure Study Type Ref. (MRID) Maxim

%AR 

PARENT

Etridiazole 5-ethoxy-3-

trichloromethyl-1,2,4-

thiadiazole

CAS No.: 2593-15-9 

Formula: C5H5Cl3N2OS

MW: 247.5 g/mol 

Smile code: 

C(OC1=NC(=NS1)C(Cl)(Cl)C

l)C 

TRANSFORMATION PRODUCTS 

3-dichloromethyl-5-

ethoxy-1,2,4-

thiadiazole 

(3-DCMT)

Formula: C5H6Cl2N2OS

MW: 213.1 g/mol Smile string:CCOC1=NC(=NS1)C(Cl)Cl 

Photolysis in 

soil 43124301 2.19-2

at 14 

Aerobic soil 

metabolism 43504301 

7% a

days in 

0.32 at 

in vola

5-ethoxy-1,2,4-

thiadiazole-3-

carboxylic acid 

(3-Carb-T) 

CAS No.: Formula: C5H6N2O3S 

MW: 174.2 g/mol

Smile string: O=C(O)C1=NSC(=N1)OCC 

Hydrolysis 00001650 65.4-7

Photolysis in 

soil 43124301 26.4-3

Aerobic soil 

metabolism 43504301 6.7% 

day

5-hydro-3-trichloro 

methyl-1,2,4-

thiadiazole (5-

hydroxy-etridiazole or 

5-OH-Terr) 

Formula: C3HCl3N2OS 

MW: 219.473

Smile string: O(C1=NC(=NS1)C(Cl)(Cl)Cl)[H] 

Photolysis on 

soil 43124301 <0.6
11 

Code Name/ Synonym Chemical Name Chemical Structure Study Type Ref. (MRID) Maxim

%AR 

5-ethoxymonochloromethyl1,2,4-thiadizole (3-

monochloromethyletridiazole or 3-MCLTerr) 

Formula: C5H7ClN2OS 

MW: 178.636 g/molSmile string: C(OC1=NC(=NS1)C(Cl)([H])[H])C 

Photolysis on 

soil 43124301 <0.6

Oxalic acid 

CAS No: 144-62-7Formula: C2H2O4

MW: 90.03 g/mol Smile string: C(=O)(C(=O)O)O 

Hydrolysis 00001650 

Sm

amount

specifi

the st

CO2

CAS No: 124-38-9 

Formula: CO2

MW: 44.01 g/mol Smile string: C(=O)=O 

Aerobic soil 

metabolism 43504301 

21.5-2

at 120

day
12 

6. Receptors 

The most sensitive aquatic and terrestrial toxicity data for etridiazole and its degradates are 

summarized in Table 4 and Table 5, respectively. On an acute exposure basis, etridiazole 

is moderately toxic to both coldwater rainbow trout (Oncorhynchus mykiss) with a median 

lethal concentration to 50% of the organism tested (LC50) of 1.21 mg/L; Accession No. 

0001703) and the warmwater bluegill sunfish (Lepomis macrochirus) (LC50 = 3.27 mg/L; 

Accession No. 0001703). Additional data were provided on the toxicity of the etridiazole 

degradate 3-DCMT (MRID 44606702); the degradate is highly toxic (LC50 = 0.77 mg/L) 

to freshwater fish on an acute exposure basis. 

Because of etridiazole’s acute toxicity to freshwater fish (rainbow trout LC50 = 1.21 mg/L), 

likely persistence in water, and repeated application, an early life stage toxicity test is 

required. A rainbow trout early life-stage (ELS) test produced a no-observed adverse effect 

concentration (NOAEC) of 0.12 mg/L (MRID 42834604) with the most sensitive endpoint 

being reduced larval weight in treated fish. The study was initially classified as 

supplemental but was upgraded to acceptable after the registrant provided additional 

information to demonstrate that neither pH nor water hardness affects the toxicity or 

solubility of etridiazole. A freshwater fish full lifecycle study is recommended based on 

the ratio of EECs to the ELS NOAEC. 

A study submitted after publication of the RED supported the previous classification of 

etridiazole as moderately toxic to freshwater aquatic invertebrates (waterfleas; Daphnia 

magna) with a median effect concentration to 50% of the organism tested (EC50) of 3.1 

mg/L; MRID 45774801). A daphnid life cycle test produced a NOAEC = 0.37 mg/L (Putt 

1993) with the most sensitive endpoint being reduction in growth. 

Etridiazole has moderate toxicity (LC50 4.0 mg/L) to the estuarine/marine sheepshead 

minnow (Cyprinodon variegatus; Machado 1993c) and is moderately toxic (EC50 2.5 

mg/L) both to estuarine/marine invertebrate mysid shrimp (Americamysis bahia; Machado 

1993a) and Eastern oyster (Crassostrea virginica) with an EC50 of 2.6 mg/L (Dionne 1993). 

Given the potential for estuarine/marine exposure, particularly as a result of the chemical’s 

use on turf, both an estuarine/marine fish early life stage test and a mysid life cycle test are 

recommended. There are currently no chronic toxicity data available for estuarine/marine 

organisms exposed to etridiazole. 

Based on both acute oral (LD50 560 - 1,640 ppm) (Fletcher 1972a; Fletcher 1972c) and 

subacute dietary (LC50 1,650 to > 5,000 ppm; MRID 00624790 and MRID 00624780) data, 

etridiazole is categorized as slightly toxic to birds. In mallard ducks (Anas platyrhynchos), 

food consumption was negatively correlated with the concentration of etridiazole in the 

diet. No data have been submitted on the toxicity of etridiazole to passerine birds. An 

avian reproduction study using bobwhite quail (Colinus virginianus) resulted in reduced 

numbers of eggs laid, viable embryos, normal hatchlings and 14-day survivors (NOAEC = 

50 ppm) (MRID 43744101). In mallard duck, dietary exposure in the avian reproduction 
13 

study resulted in reduced body weight in treated females as compared to controls (MRID 

43744102). 

Etridiazole is no more than slightly toxic to small mammals on an acute oral basis (LD50

>1,028 ppm; MRID 43724501). Chronic toxicity testing suggested a potential for chronic 

effects, but the two-generation reproduction study in rats was classified as invalid and 

provides no endpoints suitable for risk assessment (Accession No. 000041698). A new 

two-generation reproduction study with rats has been submitted and is in review by the 

Health Effects Division (HED). An inhalation study with Sprague-Dawley rats (Rattus 

norvegicus) resulted in clinical signs of toxicity but no mortalities for 14 days following 

the four-hour exposure period (MRID 43724503). 

No toxicity data have been submitted for non-target terrestrial plants. With respect to 

aquatic plants, etridiazole appears to be more toxic to nonvascular plants using green algae 

(Raphidocelis subcapitata, formerly Pseudokirchneriella subcapitata) with an LC50 of 

0.072 mg/L (Hoberg 1993b), than to vascular plants based on a study with duckweed 

(Lemna gibba) and an LC50 of 8.1 mg/L (Hoberg 1993e). However, there is greater 

uncertainty surrounding the duckweed data due to poor test substance recovery and failure 

to include solvent controls. A new test with vascular aquatic plants exposed to etridiazole 

(preferably TEP) is recommended to support risk estimation. 

No data have been submitted on the toxicity of etridiazole to terrestrial invertebrates (i.e., 

honey bee; Apis mellifera) or to benthic aquatic invertebrates (e.g., midge larvae; 

Chironomus spp.). Three screening-level tests (adult acute contact toxicity, adult acute 

oral toxicity, and larval toxicity) with honey bee are recommended. No data are 

recommended for benthic invertebrates at this time because etridiazole is not expected to 

partition to sediment. 

Table 4. Summary of the Most Sensitive Toxicity Endpoints for Etridiazole TGAI. 

Group Species 

(Common Name) 

Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID or Acc. No. 

(Study 

Classification) 

Aquatic Organisms 

Freshwater 

Fish§

Oncorhynchus mykiss 

(Rainbow Trout) 

LC50 

(96 hours) 

1,210 μg a.i./L

(Mortality) 

0001703 

(Acceptable) 

NOAEC 

(60 days posthatch) 

120 μg a.i./L 

 (Larval weight) 

42834604 

(Supplemental) 

Freshwater 

Invertebrates 

Daphnia magna 

(Water Flea) 

EC50

(48 hours) 

3,080 μg a.i./L 

(Immobility) 

45774801 

(Acceptable) 

NOAEC 

(21 days) 

370 μg a.i./L 

(Dry weight) 

42834605 

(Acceptable) 

Estuarine/ 

Marine Fish 

Cyprinodon variegatus 

(sheepshead minnow) 

LC50 

(96 hours) 

4,000 μg a.i./L 

 (Mortality) 

4283601 

(Acceptable) 
14 

Group Species 

(Common Name) 

Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID or Acc. No. 

(Study 

Classification) 

NOAEC 

(28 days posthatch) 

Data Gap N/A 

Estuarine/ 

Marine 

Invertebrates 

Crassostrea virginica 

(eastern oyster)

EC50

(96 hours) 

2,600 μg a.i./L 

 (Shell Deposition) 

4234602 

(Supplemental) 

Americamysis bahia 

(mysid shrimp)

LC50

(96 hours) 

2,500 μg a.i./L 

 (Mortality) 

42834603 

(Acceptable) 

Americamysis bahia 

(mysid shrimp)

NOAEC 

(28 days) Data Gap N/A 

Vascular Plants Lemna gibba 

(duckweed) 

IC50

(14 days) 

8,120 μg a.i./L 

 (Frond number) 

42834610 

(Supplemental – 

Data Gap) NOAEC 

(14 days) 

1,400 μg a.i./L 

(Frond number) 

Nonvascular 

Plants 

Raphidocelis 

subcapitata* 

(green algae) 

IC50

(120 hours) 

72 μg a.i./L 

(Cell Density) 42834606 

(Acceptable) NOAEC 

(120 hours) 

2 μg a.i./L 

(Cell Density) 

Terrestrial Organisms 

Avian‡

Colinus virginianus

(northern bobwhite 

quail) 

Oral LD50 

560 mg a.i./kg-bw 

(Survival) 

00002238 

(Acceptable) 

Dietary LC50 

(5 days) 

>5,000 mg/kg-diet 

(Survival) 

624780 

(Supplemental) 

NOAEC 

(27 weeks) 

50 mg/kg-diet 

(Hatchling viability) 

43744101 

(Supplemental) 

Anas platyrhynchos 

(mallard duck) 

Oral LD50 

1,640 mg a.i./kg-bw 

(Survival) 

0003276 

(Supplemental) 

Dietary LC50 

(5 days) 

1,650 mg/kg-diet 

(Survival) 

624790 

(Supplemental) 

NOAEC 

 (27 weeks) 

50 mg a.i./kg-diet†

(Female body weight) 

43774102 

(Supplemental) 

passerine Oral LD50 Data Gap N/A 

Mammals Rattus norvegicus

(laboratory rat) 

LD50 1028 mg a.i./kg-bw 43724501 

(Acceptable) 

NOAEL Data Gap N/A 

Inhalation LC50 >5.7 mg/L 43724503 

(Acceptable) 

Terrestrial 

Invertebrates 

Apis mellifera 

(honey bee) 

LD50 

(48 hours) Data Gap N/A 

Plants 

(Vegetative 

Vigor) 

Dicots IC25

Data Gap (TEP) N/A NOAEC 

Monocots IC25

NOAEC 

Plants 

(Seedling 

Emergence) 

Dicots IC25

NOAEC Data Gap (TEP) N/A 

Monocots IC25
15 

Group Species 

(Common Name) 

Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID or Acc. No. 

(Study 

Classification) 

NOAEC 

Abbreviations: ECx Concentration that results in an effect to x% of the population. ICx Concentration that 

results in average inhibition of x%. LCx Lethal concentration to x% of the population. TEP Typical end-use 

product. TGAI Technical grade active ingredient. 

‡ Birds are surrogates for terrestrial-phase amphibians and reptiles. 

§

 Freshwater fish are surrogates for aquatic-phase amphibians. 

* Formerly Pseudokirchneriellaa subcapitata and Selenastrum capricornutum. 

The etridiazole degradate 3-DCMT is classified as highly toxic to fish (bluegill sunfish 

LC50 = 770 μg 3-DCMT/L, MRID 44606702). Following the RED, additional data were 

submitted showing that 3-DCMT is moderately toxic to freshwater invertebrates (daphnid 

EC50 = 1,100 μg 3-DCMT/L, MRID 45369401). These data support the hypothesis that 3-

DCMT is a residue of concern in the risk assessment. Data gaps remain for the acute 

toxicity of 3-DCMT to estuarine/marine fish and for the acute toxicity of 3-Carb-T to 

freshwater fish and invertebrates. 

Table 5. Summary of Degradate Toxicity Data 

Group Species Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID 

(Study 

Classification) 

5-ethxy-3-dichloromethyl-1,2,4-thiadiazole (3-DCMT) 

Freshwater fish Onchorynchus mykiss LC50

(96 hours) 770 μg 3-DCMT/L 44606702 

(Acceptable) 

Freshwater 

invertebrates Daphnia magna 

EC50

(48 Hours) 1,100 μg 3-DCMT/L 45369401 

(Acceptable) 

Estuarine/marine 

fish 

Cyprinodon 

variegatus 

LC50

(96 hours) Data Gap (Degradate) N/A 

5-ethoxy-1,2,4-thiadiazole-3-carboxylic acid (3-Carb-T) 

Freshwater fish Onchorynchus mykiss LC50

(96 hours) Data Gap (Degradate) N/A 

Freshwater 

invertebrates Daphnia magna EC50(48 Hours) Data Gap (Degradate) N/A 

a. Ecological Incidents 

The Ecological Incident Information System (EIIS) is an internal OPP database that houses 

ecological incidents that have been reported to the Agency. When available, EIIS includes 

date and location of an incident, type and magnitude of effects observed in various species, 

use(s) of pesticides known or suspected of contributing to the incident, and results of any 

chemical residue analysis or other analyses conducted during incident investigation. EIIS 

incidents are categorized according to the certainty that the incident resulted from pesticide 

exposure. A search of the EIIS for ecological incidents run on March 25, 2014, identified 

no incident reports for etridiazole. However, incidents may have occurred due to 

etridiazole exposures but may not have been reported due to various factors, such as a lack 
16 

of reporting, or a lack of observation of effects. Therefore, the lack of incident reports does 

not necessarily indicate the absence of incidents. 

No plant or wildlife incidents have been reported through OPP’s aggregate incident report 

database and no avian incidents have been captured in the Avian Incident Monitoring 

System (AIMS; American Bird Conservancy 2013)15 as of March 25, 2014. The AIMS 

database contains publicly available reports on pesticide-related avian incidents through 

2005. 

7. Exposure Pathways of Concern 

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves 

in the environment from a source to an ecological receptor. For an ecological pathway to 

be complete, it must include a source, a release mechanism, an environmental transport 

medium, a point of exposure for ecological receptors, and a feasible route of exposure. 

The environmental fate properties of etridiazole indicate the following transport 

mechanisms for potential exposure to aquatic and terrestrial organisms: 

 Direct contact 

 Spray drift 

 Runoff 

 Groundwater discharge 

 Volatilization 

The environmental fate properties and use patterns of etridiazole indicate that direct spray, 

spray drift, and runoff represent likely transport mechanisms of etridiazole to aquatic and 

terrestrial organisms. Aquatic animals may also be exposed to etridiazole via groundwater 

in subterranean habitats, or following discharge of subsurface water to the surface (e.g., via 

springs, seeps, tile drainage); however, the potential for exposure via groundwater is 

expected to be lower than via runoff to surface water. 

Environmental fate data suggest (but have not clearly demonstrated) that etridiazole has 

the potential to volatilize; thus, inhalation exposure is plausible. The Screening Tool for 

Inhalation Risk (STIR)16 identifies inhalation to vapor (but not droplet) phase etridiazole 

as a potentially significant exposure route for avian species and suggests proceeding to 

refinements (Appendix C). Therefore, we considered the extent to which an acute 

inhalation toxicity study with birds would provide useful and necessary information for the 

ecological risk assessment. In the case of etridiazole, no mortality was observed in 

mammals exposed to aerosolized test substance at orders of magnitude above the saturation 

point. A comparison of the maximum anticipated vapor dose to adjusted inhalation toxicity 

 

15 Available at: http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/index.cfm 16 The SIP and STIR models are described in detail at 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm. 
17 

data for birds suggests that birds may be exposed briefly at a level that elicited transient 

sublethal effects via inhalation exposure in mammals. However, given the complete 

absence of mortality at much higher inhalation exposure concentrations in mammals, it is 

unlikely that an acute avian inhalation toxicity test would result in a definitive toxicity 

endpoint for birds up to the maximum theoretical (i.e., saturation) concentration. 

Therefore, the inhalation exposure pathway will be considered in the ecological risk 

assessment, but additional data are not requested at this time because they are unlikely to 

change the risk conclusions. Based on the STIR results, inhalation is not expected to be a 

significant route of exposure for mammals. 

The potential for non-target organisms to be exposed to etridiazole in drinking water is 

evaluated using the Screening Imbibition Program (SIP) (Appendix D)

3

. Based on this 

screen, etridiazole exposure through drinking water is identified as a potential concern for 

both acute and chronic risk to birds. However, SIP indicates that exposure through 

drinking water alone is not expected to be a concern for acute risk to wild mammals. The 

potential contribution of drinking water exposure to chronic risk to mammals cannot be 

determined in the absence of chronic toxicity data. 

8. Analysis Plan 

In order to address the risk hypothesis, the potential for adverse effects on the environment 

is estimated. The uses, environmental fate, and ecological effects of etridiazole are 

characterized and integrated to assess the risks. This is accomplished using a risk quotient 

(ratio of exposure concentration to effects concentration) approach. Although risk is often 

defined as the likelihood and magnitude of adverse ecological effects, the risk quotientbased approach does not provide a quantitative estimate of likelihood and/or magnitude of 

an adverse effect. However, as outlined in the Overview Document (USEPA, 2004), the 

likelihood of effects to individual organisms from particular uses of etridiazole is estimated 

using the probit dose-response slope and either the level of concern (discussed below) or 

actual calculated risk quotient value. 

This analysis plan may be revised depending upon the information submitted by the public 

in response to the opening of the Registration Review docket for etridiazole. 

a. Stressors of Concern 

i. Ecological Risk Assessment 

The stressors of concern are as follows: 

 Terrestrial and Aquatic Environment: etridiazole (parent), 3-Carb-T 

(transformation product), and 3-DCMT (transformation products). 

The degradates 3-Carb-T and 3-DCMT will be considered major degradates in the drinking 

water assessment due to the structural similarities with the parent compound and because 

in the last RED, etridiazole was classified as a probable human carcinogen (USEPA, 2000). 
18 

These degradates were characterized as potential degradates of concern in the RED, and 

aquatic ecotoxicity data were required to address uncertainties regarding their hazard 

relative to parent etridiazole. For the terrestrial risk assessment, risk from 3-Carb-T and 3-

DCMT will be characterized as an uncertainty. There are currently no ecotoxicity data for 

terrestrial wildlife exposed to etridiazole degradates. 

ii. Drinking Water 

The drinking water assessments conducted to support the Registration Review human 

health risk assessments of etridiazole will incorporate model estimates of residues of 

concern, which are parent compound and 3-Carb-T and 3-DCMT, in surface and ground 

water source drinking water. In the absence of data for degradates, the Agency will follow 

a total toxic residues (TTR) approach for estimation of half-lives. 

b. Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms as described at 

http://www.epa.gov/pesticides/science/models_db.htm. 

i. Available Monitoring Data 

The Agency is not aware of surface or ground water monitoring conducted by federal and 

state agencies. However, if monitoring data of etridiazole become available, they will be 

considered in the assessment. 

c. Measures of Effect 

Toxicity data presented in Section 3 of this problem formulation will be used to calculate 

risk quotients. Any additional information submitted by the registrant or found in the open 

literature meeting the standards established by the Agency prior to conduct of the risk 

assessment will also be considered. The open literature studies are identified using EPA’s 

ECOTOXicology database (ECOTOX)17, which employs a literature search engine for 

locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The 

evaluation of both sources of data can also provide insight into the direct and indirect 

effects of pesticides on biotic communities from loss of species that are sensitive to the 

chemicals and from changes in structure and functional characteristics of the affected 

communities. 

 

17 http://cfpub.epa.gov/ecotox/
19 

9. Endangered Species Assessments 

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to listed species from registered uses of pesticides in 

Registration Review. The process for evaluating potential risks to listed species is further 

described at http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm. 

10. Endocrine Disruptor Screening Program 

Etridaizole was not included in the first group of 67 chemicals issued an order to conduct 

Tier 1 and Tier II EDSP testing. For additional information the EDSP program, visit 

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

11. Preliminary Identification of Data Gaps 

a. Environmental Fate 

Table 6 identifies environmental fate studies, by MRID, that provide data for each 

guideline requirement, as well as study classifications and whether or not further data are 

needed in order to support risk assessment. 

Table 6. Submitted Environmental Fate Data for Etridiazole. 

OCSPP 

Guideline Data Requirement Submitted 

MRIDs 

Study 

Classification 

Are data needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

835.2120 Hydrolysis 00001650 Acceptable No 

835.2370 Aqueous Photolysis Waived No 

835.2410 Soil Photolysis 43124301 Acceptable No 

835.4100 Aerobic Soil 

Metabolism 43504301 Acceptable No 

835.4200 Anaerobic Soil 

Metabolism Not submitted No 

835.4300 Aerobic Aquatic 

Metabolism 45366003 Invalid Yes 

In the absence of data 

the Agency will assume 

that etridiazole is stable 

to aerobic aquatic 

metabolism* 
20 

OCSPP 

Guideline Data Requirement Submitted 

MRIDs 

Study 

Classification 

Are data needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

835.4400 Anaerobic Aquatic 

Metabolism 43504305 Invalid Yes 

In the absence of data 

the Agency will have 

uncertainty regarding 

the role of anaerobic 

aquatic environment in 

the parent molecule, 3-

DCMT and 3-Carb-T*

835.1230 

Adsorption/ 

Desorption batch 

equilibrium 

43504302, 

43504303, 

43504304 

Acceptable No 

835.1240 Aged Column 

Leaching 

0120367 

0120370 Supplemental No 

835.1410 Lab Volatility 43024101 Acceptable No 

835.6200 Terrestrial; Field 

Dissipation 

44689601 Supplemental 

44689602 Supplemental No 

44689603 Supplemental 

835.6100 Aquatic Field 

Dissipation 0120383 Unacceptable No 

835.1730 Bioaccumulation in 

Fish 43241401 Acceptable No 

850.6100 

Environmental 

Chemistry Methods 

(ECM) and 

Independent 

Laboratory 

Validation (ILV) in 

soil and water 

N/A Not submitted Yes 

This is a standard data 

requirement for field 

dissipation and ground 

water monitoring 

studies. ECM and 

associated ILV are not 

available for the 

method used in the 

field dissipation 

studies, though this is a 

requirement for 

acceptance of such 

studies. 

850.1730 Bioconcentration in 

Fish 43241401 Acceptable No 
21 

OCSPP 

Guideline Data Requirement Submitted 

MRIDs 

Study 

Classification 

Are data needed to 

conduct risk 

assessment? 

Justification and 

Assumptions EPA will 

Make in Absence of 

Data 

*Formation and decline of degradates, 3-Carb-T and 3-DCMT will be useful in the risk assessment. 

b. Effects 

Table 7 identifies ecological effects studies with etridiazole, by MRID (or Accession 

number), for each guideline requirement, as well as study classifications and whether or 

not additional data are needed in order to support risk assessment. Rationale for any 

additional data requested is presented below the tables. Table 8 identifies ecological 

effects studies with transformation products of etridiazole. 

Table 7. Submitted Ecological Effects Data for Etridiazole

Guideline Description—Test 

Substance 

MRID or 

Acc. No. 

Study 

Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

Avian and Mammalian Testing 

71-1 

(850.2100) 

Avian acute oral 

toxicity, waterfowl 

—TGAI 

00002238 

(Fletcher 

1972) 

Acceptable No 

71-1 

(850.2100) 

Avian acute oral 

toxicity, upland 

game bird species 

—TGAI 

00003276 

(Fletcher 

1972) 

Supplemental No 

850.2100 

Avian acute oral 

toxicity, passerine 

species—TGAI 

None N/A Yes 

In the absence of data, the 

Agency will assume that toxicity 

to passerine birds may be greater 

than to the upland game and 

waterfowl species tested. 

Nonguideline 

Avian acute 

inhalation toxicity, 

most sensitive 

species from oral 

toxicity tests -- 

TGAI 

None N/A No 

850.2200 

Avian dietary 

toxicity, waterfowl 

species—TGAI 

624780 

(Fletcher 

1973) 

Supplemental No 

Avian dietary 

toxicity, upland 

game bird—TGAI 

624790 

(Fletcher 

1973) 

Supplemental No 
22 

Guideline Description—Test 

Substance 

MRID or 

Acc. No. 

Study 

Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

71-4 

(850.2300) 

Avian reproduction, 

waterfowl 

species—TGAI 

43744102 

(Pederson 

and 

Solatycki 

1995) 

Supplemental No 

71-4 

(850.2300) 

Avian reproduction, 

upland game bird 

species—TGAI 

43744101 

(Pederson 

and 

Solatycki 

1995) 

Supplemental No 

850.2400 Wild mammal 

toxicity—TGAI None N/A Yes 

Data are needed to evaluate 

chronic toxicity to wild 

mammals, but EFED is not 

currently recommending a wild 

mammal toxicity test per OCSPP 

850.2400. Instead, EFED will 

evaluate risk to mammals based 

on toxicity data for laboratory rat 

or other mammals tested. EFED 

will consult with HED to identify 

the most appropriate acute and 

chronic toxicity endpoints. 

The RED noted a data gap for 

chronic toxicity to mammals

(two-generation reproduction in 

rat). This data gap may be 

satisfied by a more recent twogeneration rat reproduction study, 

which is in review by HED. 

850.2500 Simulated or actual 

field testing—TEP None N/A No 

Not triggered based on 

ecotoxicity data, predicted EECs, 

fate properties, and use pattern 

criteria. 

Aquatic Animal Testing 

72-2 

(850.1010) 

Freshwater 

invertebrate, acute 

toxicity—TGAI 

45774801 Acceptable No 

72-3 

(850.1025) 

Estuarine/Marine 

Mollusc acute 

toxicity—TGAI 

42834602 

(Dionne 

1993) 

Supplemental No 
23 

Guideline Description—Test 

Substance 

MRID or 

Acc. No. 

Study 

Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

72-3 

(850.1035) 

Estuarine/Marine 

crustacean acute 

toxicity—TGAI 

42834603 

(Machado 

1993a) 

Acceptable No 

850.1075 

Freshwater fish, 

acute toxicity, 

warm water 

species—TGAI 

0001703 

(Sleight 

1971) 

Acceptable No

850.1075 

Freshwater fish, 

acute toxicity, cold 

water species—

TGAI 

0001703 

(Sleight 

1971) 

Acceptable No

850.1075 

Estuarine/Marine 

fish acute 

toxicity—TGAI 

42834601 

(Macahdo 

1993) 

Acceptable No 

72-4 

(850.1300) 

Freshwater 

invertebrate, 

reproduction test—

TGAI 

42834605 

(Putt 1993) Acceptable No 

850.1350 

Estuarine/marine 

invertebrate, 

reproduction test—

TGAI 

None N/A Yes 

In the absence of data, EPA will 

be unable to assess chronic risk to 

estuarine/marine invertebrates. 

Risk will be assumed. 

850.1400 

Freshwater fish, 

early life stage 

test—TGAI 

42834604 

(Machado 

1993) 

Supplemental No 

850.1400 

Saltwater fish, early 

life stage test—

TGAI 

None N/A Yes 

In the absence of data, EPA will 

be unable to assess chronic risk to 

estuarine/marine fish. Risk may 

be assumed. 

850.1500 

Freshwater fish life 

cycle test None N/A Yes 

Aquatic EECs exceed the FW fish 

early life-stage (ELS) NOAEC 

(120 μg a.i./L); a full life cycle 

test is recommended when the 

EEC is at least one-tenth the 

NOAEC. Reproductive effects 

have been observed in other taxa 

(e.g., birds) and the ELS study 

does not provide data for 

reproductive toxicity. 

Estuarine/marine 

fish life cycle test None N/A No 

This data recommendation may 

be triggered in the future 

depending on results of the e/m 

early life stage test. 

850.1950 

Simulated or actual 

field testing for 

aquatic organisms 

None N/A No 

Higher-tier testing to address risk 

uncertainties have not been 

identified at this time. 
24 

Guideline Description—Test 

Substance 

MRID or 

Acc. No. 

Study 

Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

Sediment Testing 

850.1735 

Whole sediment 10-

d freshwater 

invertebrate—

TGAI 

None N/A No Sediment toxicity testing is not 

recommended at this time 

because etridiazole is not 

expected to partition to sediment 

(Koc=195-469 mL/g); although its 

octanol-water partition 

coefficient (Kow = 2,340) 

suggests a potential to 

bioaccumulate, bioconcentration 

factors in bluegill sunfish were 

relatively low (BCF <328x). 

850.1740 

Whole sediment 10-

d estuarine/marine 

invertebrate—

TGAI 

None N/A No 

Agency-wide 

guideline 

Whole sediment 

chronic freshwater 

and/or marine 

invertebrate—

TGAI 

None N/A No 

Insect Pollinator Testing 

850.3020 

Honey bee acute 

contact toxicity—

TGAI 

None N/A Yes 

In the absence of data, EPA will 

be unable to screen potential 

hazard and risk to terrestrial 

invertebrates from contact 

exposure. 

Nonguideline 

Honeybee acute 

oral toxicity 

study—TGAI 

None N/A Yes

In the absence of data, EPA will 

be unable to screen potential 

hazard and risk to terrestrial 

invertebrates from oral exposure.

Nonguideline Larval Toxicity 

Test—TGAI None N/A Yes

No information is available on 

toxicity of etridiazole to 

honeybee larvae. A honeybee 

larval toxicity test is part of 

EPA’s current screening process 

for terrestrial invertebrates. 

A protocol should be submitted 

before conducting this test. 

See Appendix E for further 

justification for recommending 

this study. 

850.3030 

Honeybee toxicity 

of residues on 

foliage—TEP 

None N/A No 

There is insufficient information 

on etridiazole toxicity to honey 

bee to determine whether this test 

is triggered. 

850.3040 Field testing for 

pollinators None N/A No 

Field testing to address risk 

uncertainties have not been 

identified at this time. 
25 

Guideline Description—Test 

Substance 

MRID or 

Acc. No. 

Study 

Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

Terrestrial Plant Testing 

850.4100 Seedling emergence 

(10 species)—TEP None N/A 

Yes In the absence of data, EPA will 

be unable to assess risk to nontarget terrestrial plants. Risk will 

be assumed. 850.4150 Vegetative vigor 

(10 species)—TEP Yes 

Aquatic Plant Testing 

850.4400 

Aquatic plant 

growth, vascular 

plant 

—TGAI 

42834610 Supplemental 

Yes (7-day, 

TEP 

preferred) 

Test substance recovery in this 

14-day study was poor and the 

study lacked solvent controls. In 

the absence of new data, EPA 

will be unable to estimate risk to 

vascular aquatic plants. EPA will 

assume that toxicity is greater 

than demonstrated in the 

submitted study. 

850.4500* 

Aquatic Plant, 

freshwater green 

alga species—

TGAI 

42834606 Acceptable No 

Aquatic Plant, 

freshwater diatom 

—TGAI 

42834608 Acceptable No 

Aquatic Plant, 

marine diatom 

—TGAI 

42834609 Acceptable No 

850.4550†

Aquatic Plant, 

cyanobacterium—

TGAI 

42834607 Acceptable No 

TGAI = Technical Grade Active Ingredient 

TEP = technical end product 

* Algal toxicity tests are now under guideline OCSPP 850.4500 (formerly 850.5400) 

†

 Cyanobacterium tests are now under guideline 850.4550 (formerly 850.5400) 

Table 8. Submitted Ecological Effects Data for Etridiazole Transformation 

Products.

Guideline Description—

Test Substance MRID Study Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

850.1075 

Freshwater fish, 

acute toxicity, 

cold water 

species— 

3-DCMT 

44606702 Acceptable No 
26 

Guideline Description—

Test Substance MRID Study Classification

Are data 

Needed for 

Risk 

Assessment?

Comments 

(Justification and Assumptions 

EPA will Make in Absence of 

Data) 

850.1010 

Freshwater 

invertebrate, 

acute toxicity— 

3-DCMT 

45369401 Acceptable No 

850.1075 

Estuarine/marine 

fish, acute 

toxicity — 

3-DCMT 

None N/A Yes 

In the absence of data, EPA will 

assume that 3-DCMT toxicity to 

estuarine/marine fish is equal to or 

greater than toxicity to freshwater 

fish. 

850.1075 

Freshwater fish, 

acute toxicity, 

cold water 

species— 

3-Carb-T 

None N/A Yes 

In the absence of data, EPA will be 

unable to assess the relative hazard 

and risk of 3-Carb-T to freshwater 

animals, including amphibians. Its 

toxicity will be assumed to be equal 

to or greater than the toxicity of 3-

DCMT. 850.1010 

Freshwater 

invertebrate, 

acute toxicity— 

3-Carb-T 

None N/A Yes 

* Algal toxicity tests are now under guideline OCSPP 850.4500 (formerly 850.5400) 

12. References 

Goring, C.A. I.; Laskowki; D.A., Hamaker, J.H.; and Meikle, R.W. 1975. Principles of pesticide 

degradation in soil. pp. 135-172 in (Haque, R. and Freed, V.H. eds.) Environmental 

dynamics of pesticides. Plenum Press, NY. 

USDA Crop Profiles. Available online at: http://www.ipmcenters.org/cropprofiles/CP_form.cfm 

Food and Agriculture Organization of the United Nations. FAO Pesticide Disposal Series 8. 

Assessing Soil Contamination: A Reference Manual. Appendix 2. Parameters of pesticides 

that influence processes in the soil. Editorial Group, FAO Information Division: Rome, 

2000. http://www.fao.org/docrep/003/X2570E/X2570E00.htm. 

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. United States Environmental Protection Agency (USEPA). Environmental 

Fate and Effects Division. Office of Pesticide Programs. Available at 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf. 

Thomas, R. G. 1990. Volatilization from water. In W. J. Lyman, W. F. Reehl, and D. H. 

Rosenblatt, editors. Handbook of Chemical Property Estimation Methods. American 

Chemical Society, Washington D.C.: pp 15-1 - 15-33. 

USEPA, 2000a. Revised EFED Risk Assessment for the Reregistration Eligibility Decision on 5-

ethoxy-e-tricholoromethyl-1,2,4-thiadiazole (Etridiazole; Terrazole®) Environmental 
27 

Protection Agency (USEPA). From Environmental Fate and Effects Division To Special 

Review and Reregistration Division. Memorandum issued: May 22, 2000. 

USEPA, 2000b. Reregistration Eligibility Decision (RED) Etridiazole (Terrazole®). United States 

Environmental Protection Agency (USEPA). Prevention, Pesticides And Toxic 

Subtances. Issued: Sep 2000. 

USEPA. 2014. BEAD Chemical Profile for Registration Review: Etridiazole (PC084701) 

Memorandum From Biological and Economic Analysis Division to Pesticide Reevaluation 

Division To the Pesticide Re-evaluation Divison. 
ted Environmental Fate and Effects Studies of Etridiazole 

D FATE STUDIES (as of 12/27/11) 

mas, R.J. (1976) Analytical Investigations Concerned with the Rate of Hydrolysis of Terrazole® 3-C14I: CASR-7-75 Supplement #1. 

ublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div.; Little Rock, Ark.; CDL:228143-J) 

ngh, J.E.; Thomas, R.J. (1976) Photochemical Studies of Terrazole® (5-Ethoxy-3-Trichloromethyl-1,2,4-Thiadiazole) in Aqueous 

ion: CASR-5-76. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div., Little Rock, 

CDL:228143-K) 

on-water 

J. (1993) UV-Visible Spectra of Terrazole: Lab Project Number: 9355. Unpublished study prepared by Uniroyal Chemical Co, Inc. 30

mas, R.; Chacon, M. (1982) Photochemical Studies of Terrazole in Aqueous Solutions and Soil, Dark Controls: CASR-2-82; 3760. 

ublished study received Dec 15, 1982 under 1258-812; submit- ted by Olin Corp., Stamford, CT; CDL:249071-F) 

on-soil 

mas, R.J. (1975) The Liquid Chromatographic Determination of 3-Carboxy-5-Ethoxy-1,2,4-Thiadiazole in Soil. Method CAM-37-75 

ative dated Oct 8, 1975. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div., Little 

, Ark.; CDL:228143-I) 

ar, E.J. (1976) Photochemical Studies of Terrazole® (5- Ethoxy-3-Trichloromethyl-1,2,4-Thiadiazole) in Soil: CASR-27-76. 

ublished study received Oct 20, 1976 under 1258-812; sub- mitted by Olin Corp., Agricultural Div., Little Rock, Ark.; CDL:228143-
29 

1655 Thomas, R.J. (1976) Laboratory Soil Leaching Studies Concerned with Terrazole®I (5-Ethoxy-3-Trichloromethyl

CASR-4-76. (Unpublished study received Oct 20, 1976 under 1258- 812; submitted by Olin Corp., Agricultural D

CDL:228143-M) 

120366 Redfield, D.; Gay, W.; Sieckhaus, J.; et al. (1981) Terrazole Volatization from Soils: Report No. LS-5-81; 3722. T

(Unpublished study received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249071

120369 Thomas, R.; Chacon, M. (1982) Photochemical Studies of Terrazole in Aqueous Solutions and Soil, Dark Control

(Unpublished study received Dec 15, 1982 under 1258-812; submit- ted by Olin Corp., Stamford, CT; CDL:24907

43124301 Wu, D. (1994) Soil Photolysis of 3-(carbon 14) Terrazole: Lab Project Nos. 93021; RPT00148; 9306. Unpublishe

XenoBiotic Laboratories, Inc. 135 p. 

45052001 Schocken, M. (2000) Response for the Etridiazole Soil Photolysis Study: Lab Project Number: 4009306. Unpubli

Uniroyal Chemical Company. 5 p. 

162-1 Aerobic soil metabolism 

120371 Thomas, R.; Chacon, M. (1982) Aerobic Laboratory Soil Metabolism with Terrazole (5-Ethoxy-3-trichloromethyl

CASR-5-82; 3797. (Unpublished study received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamfor

43504301 Nag, J.; Yu, W. (1994) Aerobic Soil Metabolism of (3-(carbon 14)) Terrazole: Lab Project Number: 9309. Unpub

Uniroyal Chemical Co., Inc. 95 p. 

45250201 Nag, J.; Regis, R. (1998) Determination of Aerobic Degradation Rates of (3-(carbon 14)) Etridiazole in Two Soils

97095. Unpublished study prepared by Uniroyal Chemical Company, Inc. 319 p. 

162-3 Anaerobic aquatic metab. 

43504305 Lansinger, J.; Comezoglu, S. (1994) Anaerobic Aquatic Metabolism of (3-(carbon 14)) Terrazole: Lab Project Nu

RPT00168. Unpublished study prepared by XenoBiotic Labs, Inc. 152 p. 
30 

45052002 Schocken, M. (2000) Response to the Etridiazole Anaerobic Aquatic Metabolism Study. Unpublished study prepa

Chemical Company. 6 p. 

162-4 Aerobic aquatic metab. 

45308501 Schanne, C. (1998) (Carbon 14)-Etridiazole: Aerobic Aquatic Metabolism: Lab Project Number: 97062: 1055.000

Unpublished study prepared by Springborn Laboratories (Europe) AG. 215 p. 

45366003 Shocken, M. (2001) Characterization of Sediments (Based on USDA Classification System) and Waters Used in a

Aquatic Metabolism Study (UCC 97062)--Supplement: Lab Project Number: 2001-048. Unpublished study prepa

Chemical and Agvise Labs. 23 p. 

 163-1 Leach/adsorp/desorption 

1649 

Thomas, R.J. (1976) Chemodynamic Parameters of Terrazole®I (5-Ethoxy-3-Trichloromethyl-1,2,4-Thiadiazole) 

20-76. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div., LiCDL:228143-G) 

1655 Thomas, R.J. (1976) Laboratory Soil Leaching Studies Concerned with Terrazole®I (5-Ethoxy-3-Trichloromethyl

CASR-4-76. (Unpublished study received Oct 20, 1976 under 1258- 812; submitted by Olin Corp., Agricultural D

CDL:228143-M) 

59110 Thomas, M.P. (1965) Letter sent to R.F. Philpitt dated Sep 15, 1965: Soil persistence of Olin 2424 (Terrazole). (U

received Sep 21, 1965 under unknown admin. no.; submitted by Olin Corp., Stamford, Conn.; CDL:127122-A) 

59117 Thomas, M.P. (1965) Letter sent to H.H. Klein dated Oct 22, 1965: Olin 2424 residues in cotton bolls, leaves and 

studies started on July 7, 1965). Unpublished study received May 28, 1970 under 0F0977; submitted by Olin CheProducts, Div. of Olin Corp., Stamford, Conn.; CDL: 091717-W) 

59118 Thomas, M.P. (1965) Letter sent to H.H. Klein dated Nov 3, 1965: Olin 2424 and Terraclor residues in soils from 

(EC) fall cotton seedling tests run in Texas. (Unpublished study received May 28, 1970 under 0F0997; submitted 

Consumer Products, Div. of Olin Corp., Stamford, Conn.; CDL:091717-AA) 
31 

120364 Thomas, R.; Horvath, J. (1982) Chemodynamic Parameters of Terrazole (5-Ethoxy-3-trichloromethyl-1,2,4-thiadi

CASR-20-76; 2919. (Unpublished study received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamfo

120367 Thomas, R.; Humphrey, E.; Horvath, J.; et al. (1982) Laboratory Soil Leaching Studies Concerned with Terrazole 

Trichloromethyl-1,2,4-thiadiazole): CASR-1-82; 3747. (Unpub- lished study received Dec 15, 1982 under 1258-8Corp., Stamford, CT; CDL:249071-D) 

120370 Thomas, R.; Burger, R. (1982) Laboratory Soil Leaching Studies with Terrazole [Ring-3-14C| and 3-Carboxy-5-et

Dutch Guidelines: CASR-4-82; 3793. (Unpublished study received Dec 15, 1982 under 1258-812; submitted by O

CDL:249071-G) 

5001190 Helling, C.S.; Dennison, D.G.; Kaufman, D.D. (1974) Fungicide movement in soils. Phytopathology 64(8):1091-43504302 Dzialo, D. (1994) Adsorption/Desorption of Etridiazole: Lab Project Number: 93127. Unpublished study prepared 

Co., Inc. 51 p. 

43504303 Dzialo, D. (1994) Adsorption/Desorption of 5-Ethoxy-1,2,4- thiadiazole-3-carboxylic Acid: A Soil Metabolite of 

Number: 9456. Unpublished study prepared by Uniroyal Chemical Co., Inc. 52 p. 

43504304 Dzialo, D. (1994) Adsorption/Desorption of 5-Ethoxy-3- dichloromethyl-1,2,4-thiadiazole: A Soil Metabolite of E

Number: 9457. Unpublished study prepared by Uniroyal Chemical Co., Inc. 52 p. 

163-2 Volatility - lab 

158122 

Reinhart, J. (1964) Letter sent to R. Philpitt dated Nov 30, 1964: Volatility of Olin 2424. Prepared by Squibb Divi

43024101 Reynolds, J. (1993) Laboratory Volatility of (3-carbon 14) Terrazole: Lab Project Number: 93023: RPT00146: 93

prepared by XenoBiotic Labs., Inc. 151 p. 

164-1 Terrestrial field dissipation 
32 

1659 Kuchar, E.J. (1976) Field Soil Dissipation Studies Concerned with Terrazole® I (5-Ethoxy-3-Trichloromethyl-1,2

6-76. (Unpublished study received Oct 20, 1976 under 1258- 812; submitted by Olin Corp., Agricultural Div., LiCDL:228143-S) 

1660 Kuchar, E.J. (1976) Field Soil Dissipation Studies Concerned with Terrazole® I (5-Ethoxy-3-Trichloromethyl-1,2

CASR-6-76: Supplement #1. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp

Little Rock, Ark.; CDL:228143-T) 

59110 Thomas, M.P. (1965) Letter sent to R.F. Philpitt dated Sep 15, 1965: Soil persistence of Olin 2424 (Terrazole). (U

received Sep 21, 1965 under unknown admin. no.; submitted by Olin Corp., Stamford, Conn.; CDL:127122-A) 

59114 Kuchar, E.J. (1969) Letter sent to H.H. Klein dated Aug 7, 1969: Soybeans--Emory Fultz--soil. (Unpublished stu

1970 under 0F0997; submitted by Olin Chemicals, Consumer Products, Div. of Olin Corp., Stamford, Conn.; CD

59115 Kuchar, E.J. (1969) Letter sent to H.H. Klein dated Aug 7, 1969: Soybean soil--Emory Fultz. (Unpublished study 

under 0F0997; submitted by Olin Chemicals, Consumer Products, Div. of Olin Corp., Stamford, Conn.; CDL:09

59116 Kuchar, E.J. (1969) Letter sent to H.H. Klein dated Aug 7, 1969: Soil--PAG Farm, Urbana, Illinois. (Unpublishe

1970 under 0F0997; submitted by Olin Chemicals, Consumer Products, Div. of Olin Corp., Stamford, Conn.; CD

59118 Thomas, M.P. (1965) Letter sent to H.H. Klein dated Nov 3, 1965: Olin 2424 and Terraclor residues in soils from 

(EC) fall cotton seedling tests run in Texas. (Unpublished study received May 28, 1970 under 0F0997; submitted 

Consumer Products, Div. of Olin Corp., Stamford, Conn.; CDL:091717-AA) 

59133 Thomas, R.J. (1976) Letter sent to E.J. Kuchar dated Sep 20, 1976: Field leaching. (Unpublished study received O

812; submitted by Olin Corp., Stamford, Conn.; CDL: 228143-N) 

59152 Thomas, M.P. (1965) Letter sent to R.F. Philpitt dated Nov 11, 1965: Soils from 1965 Terraclor Super X (EC), fa

(Unpublished study received Feb 16, 1968 under 1258-818; submitted by Olin Corp., Stamford, Conn.; CDL: 10

59153 Sisken, H.R. (1966) Letter sent to H.H. Klein dated Dec 1, 1966: PCNB and 2424 residue in cotton. (Unpublishe

1968 under 1258-818; submitted by Olin Corp., Stamford, Conn.; CDL:101585-W) 

59154 Sisken, H.R. (1967) Letter sent to H.H. Klein dated Apr 11, 1967: Degradation of 2424 and PCNB in cotton soil 

study received Feb 16, 1968 under 1258-818; submitted by Olin Corp., Stamford, Conn.; CDL:101585-X) 

93750 Kuchar, E.J.; Griffith, W.P.; HH, H.H.; et al. (1970) Analytical Studies of the Metabolism of Terrazole® (5-Ethox

1,2,4-thiadiazole) in Animals and Plants: 3467. (Unpublished study received Jan 20, 1982 under 1258-812; sub- 

Stamford, Conn.; CDL:070614-F) 
33 

120373 Csinos, A.; Peets, N. (1981) Residue Data Report: Bush Bean Soil: Blue Lake Variety Treated with Dwell 4E|: R

2. (Unpublished study received Dec 15, 1982 under 1258- 812; submitted by Olin Corp., Stamford, CT; CDL:249

120374 Turner, F.; Jund, M. (1981) Residue Data Report: Rice Soil: Pecos Variety Treated with Dwell|: Report No. 81-7

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249071-K) 

120375 Turner, F.; Jund, M. (1981) Residue Data Report: Rice Soil: Newrex Variety Treated with Dwell|: Report No. 81

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249071-L) 

120376 Nelson, D. (1982) Residue Data Report: Corn Soil Treated with Dwell|: Report No. 81-8-2. (Unpublished study 

under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249071-M) 

120377 Maples, R. (1981) Residue Data Report: Cotton Soil: Variety D+ PL 61 Treated with Dwell|: Report No. 81-8-3

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249071-N) 

120378 McDaniel, M. (1982) Residue Data Report: Turf Soil|: Report No. 81-11-1. (Unpublished study received Dec 15

submitted by Olin Corp., Stamford, CT; CDL:249072-A) 

120379 Wells, B. (1981) Residue Data Report: Rice Soil: Labonnet Variety Treated with Dwell|: Report No. 81-12-3. (U

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249072-B) 

120380 Wells, B. (1982) Residue Data Report: Rice Soil: Labonnet Variety Treated with Dwell 1 lb/A|: Report No. 82-1

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249072-C) 

120382 Mikkelsen, D. (1982) Residue Data Report: Rice Soil: M 101 Variety Treated with Dwell|: Report No. 82-3-1. (U

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249072-E) 

120384 Ohr, H. (1982) Residue Data Report: Avacado Soil: Fuerte Variety Treated with Terrazole 5% Granular (.18 oz. 

No. 82-8-1. (Unpublished study received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; 

44452501 Uniroyal Chemical Company, Inc. (1997) Progress Report: Etridiazole Field and Turf Dissipation Studies: Lab P

RP96026: RP96029: 97058. Unpublished study. 19 p. 

44689601 Singer, G. (1998) Field Soil Dissipation of Terrazole 35 WP in Turf and Bareground in North Carolina: Final Re

Number: 97058: AA970306: NCL 20.064. Unpublished study prepared by American Agricultural Services, Inc. Laboratories. 674 p. 
34 

44689602 Singer, G. (1998) Field Soil Dissipation of Terraclor Super X 18.8 G and Terraclor Super X EC in Bareground in 

Amended Final Report: Lab Project Number: RP-96026: NCL 20.062. Unpublished study prepared by American Inc. and North Coast Laboratories. 651 p. 

44689603 

Singer, G. (1998) Field Soil Dissipation of Terrazole 35 WP in Turf and Bareground in California: Final Report: RP-96029: NCL 20.060. Unpublished study prepared by American Agricultural Services, Inc. and North Coast L

44864901 Wood, B. (1999) Freezer Storage Stability of Etridiazole and Two Metabolites in Texas Clay Soil: Final Report: 

98028: 20.065: AA98031. Unpublished study prepared by North Coast Labs., Ltd. and American Agricultural Se{OPPTS 860.1380} 

45052003 Schocken, M. (2000) Response to the Terrazole Field Dissipation: Lab Project Number: 96029. Unpublished stud

Chemical Company. 14 p. 

45366002 Shocken, M. et al. (2001) Characterization of Soils Used in Etridiazole Soil Degradation Rate Study (UCC 97095

Classification System--Supplement: Lab Project Number: 2001-045. Unpublished study prepared by Uniroyal Ch22 p. 

 164-2 Aquatic field dissipation 

120383 Mikkelsen, D. (1982) Residue Data Report: Rice Water: M 101 Variety Treated with Dwell|: Report No. 82-3-2. (

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249072-F) 

165-1 Confined rotational crop 

44311401 Yu, W.; Nag, J.; Chan, J.; et al. (1997) Confined Accumulation Study on Rotational Crops with (carbon 14)-Etrid

Report): Lab Project Number: 93182/9389: 93276: 9389. Unpublished study prepared by ABC Labs California anCo., Inc. 540 p. {OPPTS 860.1850} 

165-4 Bioaccumulation in fish 
35 

43241401 Schocken, M. (1994) Etridiazole (Terrazole)-Bioconcentration Exposure with Bluegill Sunfish (Lepomis macroch

Resulting Metabolites: Amended Final Report: Lab Project Number: 41.0693.6139.140: 93-12-5104: 9356. UnpubSpringborn Labs., Inc. 127 p. 

1663 Iwan, G.R. (1976) Olin--14C Terrazole Channel Catfish, Ictalurus punctatus (Rafinesque), Static Bioaccumulation 

study received Oct 20, 1976 under 1258-812; prepared by Union Carbide Corp., Aquatic Environmental Sciences, Agricultural Div., Little Rock, Ark.; CDL:228143-AB) 

Non Guideline Selections 

1567 Kvien, C. (1975) Nitrification Inhibition in Soils by Terrazole: (Master's thesis, Southern Illinois University, Depa

Science). (Unpublished study that includes report no. 3067, received Feb 4, 1977 under 1258-812; submitted by ODiv., Little Rock, Ark.; CDL: 095799-J) 

1595 Kuchar, E.J. (1970) Determination of Terraclor (Pentachloronitrobenzene) and Terrazole (5-Ethoxy-3-Trichlorom

in Soil: Analytical Method. Method CAM-12-70 dated Apr 28, 1970. (Unpublished study received May 28, 1970 u

by Olin Corp., Stamford, Conn.; CDL:091717-B) 

1646 Thomas, R.J. (1976) Chemodynamic Parameter of Terrazole®I (5-Ethoxy-3-Trichloromethyl-1,2,4-Thiadiazole) P

Octanol vs Water: CASR-18-76. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Co

Little Rock, Ark.; CDL:228143-D) 

1657 Thomas, R.J. (1976) Laboratory Soil Metabolism Studies Concerned with Terrazole®I (5-Ethoxy-3-Trichlorometh

CASR-7-76. (Unpublished study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural DiCDL:228143-Q) 

1658 Thomas, R.J. (1976) Identification of 3-Dichloromethyl-5-Ethoxy- 1,2,4-Thiadiazole as a Metabolite of Terrazole® 

(Unpublished study received Oct 20, 1976 under 1258- 812; submitted by Olin Corp., Agricultural Div., Little Roc

1661 Kuchar, E.J. (1973) Residues of Terraclor® and Terrazole® in Soil--1972 Studies: CASR-19-73. (Unpublished stud

under 1258-812; submitted by Olin Corp., Agricultural Div., Little Rock, Ark.; CDL:228143-X) 

1662 Kuchar, E.J. (1976) Terrazole® (5-Ethoxy-3-Trichloromethyl-1,2, 4-Thiadiazole) Greenhouse Studies in Soil: CAS

study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div., Little Rock, Ark.; CDL:

1664 Ercegovich, C.D. (1976) Effects of 5-Ethoxy-3-(Trichloromethyl)- 1,2,4-Thiadiazole (Terrazole) on Microorganis

Processes in Soil: Report No. E-1/1-76 (0). (Unpublished study received Oct 20, 1976 under 1258-812; prepared bUniv.--University Park, Pesticide Research Laboratory, submitted by Olin Corp., Agricultural Div., Little Rock, A
36 

1717 Thomas, M.P. (1965) Summary of Terraclor Super X Residues in Soil from 1965: Standard Cotton Tests: Table 4. 

includes tables 25 and 26, received Mar 24, 1970 under 9F0754; submitted by Olin Mathieson Chemical Corp., Ne

CDL:091299-Y) 

28421 or 100334 Iacoviello, S.A. (1977) Determination of Terrazole® (5-Ethoxy- 3-trichloromethyl-1,2,4-thiadiazole) and Terraclor

chloronitrobenzene) Impurities and Allied Metabolites in Water Samples. Method CAM-30-77 dated Jun 1, 1977

received Jan 23, 1980 under 1258-1003; submitted by Olin Corp., Stamford, Conn.; CDL:099210-D) 

64188 or 1651 Thomas, R.J. (1975) The Liquid Chromatographic Determination of 3-Carboxy-5-ethoxy-1,2,4-thiadiazole in Soil

CAM-37-75 dated Sep 26, 1975. (Unpublished study received Oct 13, 1977 under 6E1747; prepared by Olin Corp

California, Dept. of Food and Agriculture, Sacramento, Calif.; CDL:097259-D) 

64193 Kuchar, E.J.; Griffith, W.P. (1970) Determination of Terraclor (Pentachloronitobenzene) and Terrazole (5-Ethoxy

1,2,4-thiadiazole) in Soil. Method no. CAM-12-70 dated Apr 28, 1970. (Unpublished study received Jul 20, 1971 

by Olin Corp., Stamford Conn.; CDL:111186-B) 

100333 Iacoviello, S.A.; DeFonzo, D.J. (1979) Activated Sludge Test for Terrazole® 3-C14 (3-Trichloromethyl-5-ethoxy-1

CASR-14-79. (Unpublished study received Jul 6, 1979 under 1258-812; submitted by Olin Corp., Stamford, Conn

5011881 Laski, R.R.; Watts, R.R. (1973) Gas chromatography of organonitrogen pesticides, using a nitrogen-specific detec

the Association of Official Analytical Chemists 56(2):328-332. 

45366001 Ma, Q.; Cohen, S.; Barnes, N. et al. (2001) Use of PRZM-EXAMS to Estimate Aquatic Concentrations of Etridiaz

Following Use on Golf Courses: Lab Project Number: ETS 0028-AG: 2001-003. Unpublished study prepared by EServices, Inc. 55 p. 

1656 Schingh, J.E. (1976) Determination of Soil Moisture Retention by Tensiometric Technique: CASR-2-76. Undated 

study received Oct 20, 1976 under 1258-812; submitted by Olin Corp., Agricultural Div., Little Rock, Ark.; CDL:

120381 Wells, B. (1982) Residue Data Report: Rice Water: Labonnet Variety Treated with Dwell 1 lb/A|: Report No. 81-1

received Dec 15, 1982 under 1258-812; submitted by Olin Corp., Stamford, CT; CDL:249072-D) 
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

PC Code 084701-SUBMITTED EFFECT STUDIES (as of 2/3/2014) 

71-1 Avian Single Dose Oral Toxicity

MRID Citation Reference

2226 Dieterich, W.H. (1965) Acute Dietary Administration-Wildfowl: Terraclor Super X: Final Report: Project No. 791-100. (Unpublished 

unknown admin. no.; prepared by Hazleton Laboratories, Inc., submitted by Squibb Institute for Medical Research, New Brunswick, 

2238 Fletcher, D. (1972) Report to Olin Corporation: Acute Oral Toxicity Study with Olin Terrazole in Mal ard Ducks: IBT No. J891. (Un- 

Feb 15, 1972 from J.C. Calandra to John H. Wedig, received Mar 3, 1972 under 1258-826; prepared by Industrial Bio-Test Labora

Stamford, Conn.; CDL:005836-A)

3276 Fletcher, D. (1972) Report to Olin Corporation: Acute Oral Toxicity Study with Olin Terrazole, D8364 FOG in Bobwhite Quail: IBT No

J890. (Unpublished study including letter dated Jan 26, 1972 from J.C. Calandra to John H. Wedig, received Mar 3, 1972 under 125

prepared by Industrial Bio-Test Laboratories, Inc., submitted by Olin Corp., Stamford, Conn.; CDL:005836-B)

71-2 Avian Dietary Toxicity

MRID Citation Reference

59122 Dieterich, W.H. (1965) Letter sent to Sylvan I. Cohen dated Aug 2, 1965 Review of wildlife testing of Terraclor Super X status|. (Unp

21, 1965 under 1258-740; pre- pared by Hazleton Laboratories, Inc., submitted by Olin Corp., Stamford, Conn.; CDL:050929-

62478 Fletcher, D.W. (1981) Report to Olin: 8-Day Dietary LC50 Study with Terrazole® Technical in Bobwhite Quail: BLAL No. 80 QC 

study received Apr 7, 1981 under 1258-812; prepared by Bio-Life Associates, Ltd., sub- mitted by Olin Corp., Stamford, Conn

62479 Fletcher, D.W. (1981) Report to Olin: 8-Day Dietary LC50 Study with Terrazole® Technical in Mallard Ducklings: BLAL No. 80 DC

4; Olin Report No. 3651. (Unpublished study received Apr 7, 1981 under 1258-812; prepared by Bio-Life Associates, Ltd., sub

Conn.; CDL:244770-D)

97777 Dieterich, W.H. (1965) Acute Dietary Administration--Wildfowl: Project No. 791-100. (Unpublished study received on unknown date un

prepared by Hazleton Laboratories, Inc.; CDL:103201-A)

43715601 Pedersen, C.; Solatycki, A. (1995) 28-Day Dietary Toxicity and Reproduction Pilot Study with Terrazole Technical in Bobwhite Quail

109-019-05: 653-005. Unpublished study prepared by Bio-Life Associates, Ltd. 276 p.

43744101 Pedersen, C.; Solatycki, A. (1995) Toxicity and Reproduction Study with Terrazole Technical in Bobwhite Quail: (Final Report): Lab

Project Number: 109-021-07: 653-006. Unpublished study prepared by Bio-Life Associates, Ltd. 516 p.

43744102 Pedersen, C.; Solatycki, A. (1995) Toxicity and Reproduction Study with Terrazole Technical in Mallard Ducks: (Final Report): Lab

Project Number: 109-022-08: 653-006. Unpublished study prepared by Bio-Life Associates, Ltd. 524 p.
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

43744103 Pedersen, C.; Solatycki, A. (1995) 28-Day Dietary Toxicity and Reproduction Pilot Study with Terrazole Technical in Mallard Ducks

06: 653-005. Unpublished study prepared by Bio-Life Associates, Ltd. 268 p.

71-4 Avian Reproduction

MRID Citation Reference

43715601 Pedersen, C.; Solatycki, A. (1995) 28-Day Dietary Toxicity and Reproduction Pilot Study with Terrazole Technical in Bobwhite Quail

109-019-05: 653-005. Unpublished study prepared by Bio-Life Associates, Ltd. 276 p.

43744101 Pedersen, C.; Solatycki, A. (1995) Toxicity and Reproduction Study with Terrazole Technical in Bobwhite Quail: (Final Report): Lab

Project Number: 109-021-07: 653-006. Unpublished study prepared by Bio-Life Associates, Ltd. 516 p.

43744102 Pedersen, C.; Solatycki, A. (1995) Toxicity and Reproduction Study with Terrazole Technical in Mallard Ducks: (Final Report): Lab

Project Number: 109-022-08: 653-006. Unpublished study prepared by Bio-Life Associates, Ltd. 524 p.

43744103 Pedersen, C.; Solatycki, A. (1995) 28-Day Dietary Toxicity and Reproduction Pilot Study with Terrazole Technical in Malard Ducks: 

06: 653-005. Unpublished study prepared by Bio-Life Associates, Ltd. 268 p.

72-1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

1572 Dieterich, W.H. (1965) Acute Aqueous Exposure--Fish: Terraclor Super X--Final Report: Project No. 791-101. (Unpublished study rec

prepared by Hazleton Laboratories, Inc., submitted by Squibb Institute for Medical Research, New
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Brunswick, N.J.; CDL:131392-A)

1703 Sleight, B.H., III (1971) Bioassay Report: Acute Toxicity of Terrazole (D-8364) to Bluegill (Lepomis macrochirus) and Rainbow Trout (

study that in- cludes wel water quality analysis p. 13, received Nov 23, 1971 under 1258-826; prepared by Bionomics, Inc., subm

CDL:101583-A)

97776 Dieterich, W.H. (1965) Acute Aqueous Exposure--Fish: Project No. 791-101. (Unpublished study received on unknown date under unk

Hazleton Laboratories, Inc.; CDL:103200-A)

44606702 Sousa, J. (1998) 5-Ethoxy-3-Dichloromethyl-1,2,4-Thiadiazole (T-03)--Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) Und

Final Report: Lab Project Number: 41.0198.6158.108: 98-3-7284. Unpublished study prepared by Springborn Labs., Inc. 68 p.

45774802 Dionne, E. (2002) Etridiazole--Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss) Under Flow-Through Conditions: Lab Projec

Number: 41.6177. Unpublished study prepared by Springborn Smithers Laboratories. 54 p. {OPPTS 850.1075}

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

62477 LeBlanc, G.A.; Surprenant, D.C.; Sleight, B.H., III. (1979) Acute Toxicity of Terrazole to the Water Flea (Daphnia magna): Report 

#

BW-79-12-580; Olin Report No. 1029-79. (Unpublished study received Apr 7, 1981 under 1258-812; prepared by EG&G, Bio

Stamford, Conn.; CDL: 244770-B)

44606701 Putt, A. (1998) 5-Ethoxy-3-Dichloromethyl-1,2,4-Thiadiazole (T-03)--Acute Toxicity to Daphnids (Daphnia magna) Under Flow- Th

Final Report: Lab Project Number: 41.0198.6157.115: 98-3-7294. Unpublished study prepared by Springborn Labs., Inc. 65 p.

44848301 Lengen, M. (1999) Response to EPA Review for Acute Toxicity Test with Terrazole Metabolite T-03. Unpublished study prepared by

Uniroyal Chemical Company, Inc. 25 p.

44992901 Lengen, M. (1999) DER Response for Acute Toxicity Test with Terrazole Metabolite T-03 and Daphnia magna. Unpublished study p

Co., Inc. 6 p.

45369401 Putt, A. (2001) 5-Ethoxy-3-Dichloromethyl-1, 2, 4-Thiadiazole (T-03)--Acute Toxicity to Daphnids (Daphnia magna) Under Flow- T

Number: 41. 6167: 060900/OECD/EC/115. Unpublished study prepared by Springborn Labs., Inc. 53 p.
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

45774801 Dionne, E. (2002) Etridiazole--Acute Toxicity to Daphnids (Daphnia magna) Under Flow-Through Conditions: Lab Project Number:

41.6176. Unpublished study prepared by Springborn Smithers Laboratories. 55 p. {OPPTS 850.1010}

72-3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

42834601 Machado, M. (1993) Terrazole Technical--Acute Toxicity to Sheepshead Minnow (Cyprinodon variegatus) under Flow-Through Con

Number: 93-3-4675: 41.1092.6130.505. Unpublished study prepared by Springborn Labs, Inc. 67 p.

42834602 Dionne, E. (1993) Terrazole Technical--Acute Toxicity to Eastern Oyster (Crassostrea virginica) under Flow-Through Conditions: Fin

Report: Lab Project Number: 93-2-4650: 41.1092.6131.504. Unpublished study prepared by Springborn Labs, Inc. 64 p.

42834603 Machado, M. (1993) Terrazole Technical--Acute Toxicity to Mysid Shrimp (Americamysis bahia formerly Mysidopsis bahia) under F

Final Report: Lab Project Number: 93-2-4622: 41.1092.6132.515. Unpublished study prepared by Springborn Labs, Inc. 67 p.

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

42834604 Machado, M. (1993) Terrazole Technical--The Toxicity to Rainbow Trout (Oncorhynchus mykiss) During an Early Life-Stage Exposur

Number: 93-5-4767: 41.1092.6128.121. Unpublished study prepared by Springborn Labs, Inc. 111 p.

42834605 Putt, A. (1993) Terrazole Technical--The Chronic Toxicity to Daphnia magna under Flow-Through Conditions: Final Report: Lab Proj

Number: 93-3-4662: 41.1092.6129.130. Unpublished study prepared by Springborn Labs, Inc. 104 p.

45052004 Lengen, M. (2000) DER Response for the Toxicity Tests with Terrazole and Rainbow Trout and Daphnia magna. Unpublished study p

Company. 25 p.

81-1 Acute oral toxicity in rats
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

MRID Citation Reference

... 43724501 Warshawsky, L. (1994) Acute Oral Toxicity Study in Rats: Terrazole Technical: Lab Project Number: 399-148. Unpublished study pr

...

81-3 Acute inhalation toxicity in rats

MRID Citation Reference

... 43724503 Hilaski, R. (1994) EPA (FIFRA) Acute Inhalation Toxicity Evaluation on Terrazole Technical in Rats: Lab Project Number: 399-147.

Unpublished study prepared by IRDC. 46 p.

... 

121-1 Phytotoxicity

MRID Citation Reference

1626 Mal inckrodt Chemical Works (1970?) Phytotoxicity Limits: Soil Drench and Soil Mix with Bedding, Foliage and Potted Plants.| (Unpublishe

experimental formulation numbers, received Oct 10, 1970 under 372-UG(43); CDL: 003213-I)

1627 Mil er, H.N. (1970?) Soil Mix Phytotoxicity Using M-4 Formulations. (Unpublished study received Oct 5, 1970 under 372-UG(43): sub- m

Works; CDL:003213-K)

1628 Mil er, H.N. (1970?) Soil Drench Phytotoxicity: M69-2, M69-4. (Unpublished study received Oct 13, 1970 under 372-UG(43); sub- mitte

Works; CDL:003213-L)

1633 Mil er, H.N. (1970?) Soil Mix Phytotoxicity Studies on Foliage Plants. (Unpublished study received Oct 5, 1970 under 372-UG(43);

submitted by Mal inckrodt Chemical Works, St. Louis, Mo.; CDL:003213-Q)

1639 Nichols, L.| (1970) Phytotoxicity Test of Truban at Stan Cassel Greenhouse, Chalfont, Pa. (Unpublished study received Oct 5, 1970 under 

Mal inckrodt Chemical Works, CDL:003213-X)

1640 Nichols, L.| (1970) Phytotoxicity Test of Truban at Herman Lederer and Sons, Parkerford, Pa. (Unpublished study received Oct 5, 1970 u

Mal inckrodt Chemical Works, St. Louis, Mo.; CDL:003213-Y)

1641 Mal inckrodt Chemical Works (1970) Growth Response of Potted Chrysanthemums. (Unpublished study received Oct 5, 1970 under

372-UG(43); CDL:003213-Z)
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

1772 Mal inckrodt Chemical Works (1972?) Foliage Plants--Phytotoxicity of MF-562 and MF-563: Philodendron oxycardum. (Unpublished stu

372-EXP-9G; CDL:123408-K)

1778 Mal inckrodt Chemical Works (1973?) Fungicide Phytotoxicity on Carefree Geraniums. (Unpublished study received Jun 12, 1973 under

372-47; CDL:003217-F)

1782 Mal inckrodt Chemical Works (1973?) Bedding Plants--Phytotoxicity of MF-562 and 563: Aster, Celosia, Petunia and Salvia. (Unpublishe

under 372-47; CDL:003217-M)

1783 Mal inckrodt Chemical Works (1973?) Bedding Plants--Phytotoxicity of MF-562 and MF-563: Petunia, Snapdragon and Marigold. (Unpu

12, 1973 under 372-47; CDL:003217-N)

1784 Mal inckrodt Chemical Works (1973?) Bedding Plants--Phytotoxicity of MF-562 and 563: Marigold. (Unpublished study received Jun 12,

1973 under 372-47; CDL:003217-O)

1786 Mal inckrodt Chemical Works (1973?) Bedding Plants: Rates Tested Ozs/100 Gal. (Unpublished study received Jun 12, 1973 under 372-

47; CDL:003217-R)

1787 Mal inckrodt Chemical Works (1973?) Container and Bedgrown Plants: Rates Tested Ozs/100 Gals. (Unpublished study received Jun 12,

1973 under 372-47; CDL:003217-S)

1788 Mal inckrodt Chemical Works (1973?) Phytotoxicity Trials Using MF- 508 and MF-512 on Pittosporum, Tobira and Buxus. (Unpublished 

372-47; CDL:003217-T)

1791 Powel , C.C., Jr. (1971) Topsin-M, Trial I, II, III, IV, V, VI on Rose Powdery Mildew, Chrysanthemum Phytotoxicity, Rhizoctonia Stem R

Lophodermium Needlecast on Scotch Pine. (Unpublished study including letter dated Nov 9, 1971 from C.C. Powel , Jr. to Frederic

under 372-47; prepared by Ohio State Univ., Cooperative Extension Service, submitted by Mal inckrodt Chemical Works, St. Louis

1795 Mal inckrodt Chemical Works (1973) Bedding Plants: Rates Tested Ozs/100 Gals. (Unpublished study received Jun 19, 1973 under 372-

46; CDL:003216-E)

1796 Mal inckrodt Chemical Works (1973) Foliage Plants: Rates Tested Ozs/100 Gal ons. (Unpublished study received Jun 19, 1973 under

372-46; CDL:003216-P)

1797 Mal inckrodt Chemical Works (1973?) Container and Bedgrown Plants: Rates Tested Ozs/100 Gall ons. (Unpublished study received Jun

19, 1973 under 372-46; CDL:003216-T)

1800 DeNeve, R.T. (1973) Soil Drench Phytotoxicity Test (73-1) of Banrot and Truban 25% E.C. on Selected South Florida Nursery Plants. (U

dated Jun 13, 1973 from R.T. DeNeve to Bil W.A. Smal |, received Jun 19, 1973 under 372-46; prepared by La Casa Verde, Inc.

Chemical Works, St. Louis, Mo.; CDL:003216-AA)

1813 Mal inckrodt Chemical Works (1972) Chrysanthemum--Disease Control and Phytotoxicity. (Unpublished study received Jun 7, 1972 under 

2231 Raabe, R.D. (1970) African Violet: Toxicity Trial. (Unpublished study received Oct 5, 1970 under 372-43; prepared by Univ. of

California--Berkeley, submitted by Mal inckrodt, Inc., St. Louis, Mo., CDL:003213-S)

2246 Mal inckrodt Chemical Works (19??) Pothos--Root Rot. (Unpublished study received Jun 12, 1973 under 372-47; CDL:003217-H). Da
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

2251 Mal inckrodt Chemical Works (19??) Bedding Plants--Phytotoxicity of MF-562 and 563: Marigold Seedlings. (Unpublished study received

Jun 7, 1972 under 372-EX-9; CDL:123408-S)

2252 Mal inckrodt Chemical Works (19??) Bedding Plants--Phytotoxicity of MF-563 and MF-562: Seedlings of Celosia and Balsam. (Unpublis

372-EX-9; CDL:123408- T)

2256 Mal inckrodt, Incorporated (1975?) Bedding Plants: Phytotoxicity. (Unpublished study received Feb 4, 1975 under 372-46; CDL:

006409-A)

2265 Ol er, M.B. (1967) Ef icacy of Terraclor Super X as Saf lower Seed Treatment and Phytotoxicity: FTFDR No. MBO 5-1, MBO 6-1. (Un

16, 1968 under 1258-813; sub- mitted by Olin Corp., Stamford, Conn.; CDL:005784-BB)

2910 Uniroyal Chemical (1973) Field Performance and Phytotoxicity Report. (Unpublished study received May 1, 1974 under 4F1499; CDL:09

3001 Uniroyal Chemical (1974) Phytotoxicity. (Unpublished study received Jul 15, 1976 under 400-118; CDL:224933-B)

3126 Uniroyal Chemical (1972) 1972 Regional Cottonseed Treatment Test. (Unpublished study received May 16, 1973 under 400-107;

prepared in cooperation with Seed Treatment Committee of the Cotton Disease Council; CDL:003284-I)

5845 El is, M.A.; Hepperly, P.R.; Paschal, E.H., II; Foor, S.R. (19??) Seed treatments. Pages 189-190,~In~Fungicide and Nematicide Test, V

Phytopathological Society. St. Paul, Minn.: APS. (Also In unpublished submission received Dec 11, 1977 under

400-112; submitted by Uniroyal Chemical, Bethany, Conn.; CDL:238081-B)

9407 Pfrimmer, T.R. (1968) LV Conventional Spray Test. (Unpublished study received on unknown date under PP1144; prepared by U.S.

Agricultural Research Service, Delta Branch Experiment Station, submitted by E.I. du Pont de Nemours & Co., Inc., Wilmington, De

10205 Backman, P.A.; Rodriguez-Kabana, R.; Clark, E.M. (1972) Soil-Borne Disease Tests: Sclerotium rolfsi . (Unpublished study received Ma

prepared by Auburn Univ., Dept. of Botany and Microbiology, submitted by PPG Industries, Inc., Chemical Div., Pittsburgh, Pa.; CD

10206 Backman, P.A.; Rodriguez-Kabana, R.; Clark, E.M.; et al. (1973) Control of Sclerotium rolfsi White Mold of Peanuts. (Unpub- lished stud

748-EX-12; prepared by Auburn Univ., Dept. of Botany and Microbiology, submitted by PPG Industries, Inc., Chemical Div., Pittsb

19876 DeNeve, R.T. (1971) Foliar Phytotoxicity Tests of Truban 25% E.C. on Selected Ornamental Plants. (Unpublished study received on unkn

prepared in cooperation with Univ. of Florida, Institute of Food and Agricultural Sciences, Dept. of Plant Pathology, submitted by Ma

CDL:003215-A)

19877 DeNeve, R.T. (1971) Phytotoxicity and Disease Studies Using Truban 30% W.P. on Rhododendrons. (Unpublished study received on un- 

in cooperation with Pennsylvania State Univ., submitted by Mal inckrodt, Inc., St. Louis, Mo.; CDL:003215-C)

19881 Mal inckrodt, Incorporated (19??) ?Phytotoxicity and Ef icacy of Plants|. (Unpublished study received Apr 1, 1971 under 372-44; CDL:00

19882 Raabe, R.D. (1970) Truban: Toxicity Data on Plants|. (Unpublished study including addenda, received Apr 1, 1971 under 372-44; pre- pa

Agricultural Experiment Station, Dept. of Plant Pathology, submitted by Mal inckrodt, Inc., St. Louis, Mo.; CDL:003215-J)

19885 Mal inckrodt, Incorporated (1970) Soil Drench Phytotoxicity Studies on Foliage Plants. (Unpublished study received Apr 1, 1971 under

372-44; CDL:003215-O)

30715 Simone; Jackson, ; Couch, ; et al. (1978) Results from Tersan 1991 & Daconil Alone & in Combination on Turfgrass. (Unpublished study r

357; prepared in cooperation with Univ. of Illinois and others, submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

59132 May, J.T. (1971) Letter sent to R.T. DeNeve dated Sep 27, 1971 ?Pythium fungicides applied to pine seedbeds|. (Unpublished study rece

43; prepared by Univ. of Georgia, School of Forest Resources, submitted by Mal inckrodt, Inc., St. Louis, Mo.; CDL:003214-F)

115593 Olin Corp. (1982) Efficacy: Dwel on Rice|. (Unpublished study received Oct 13, 1982 under 1258-EX-15; CDL:071177-A)

136645 Olin Corp. (1969) Terraclor Super X Granular 10%--2.5%: Bean Utility. (Compilation; unpublished study received May 13, 1969 under

1258-758; CDL:005779-A)

163386 Interregional Research Project No. 4 (1981) Ethazole on Melons, Cucumbers, Cabbage and Peppers: [Efficacy]. Unpublished comp

163388 Interregional Research Project No. 4 (1980) Banrot on Lettuce [Cu- cumbers, Melons, Tomato and Eggplant]. Unpublished compilation.

32 p.

5006097 McCain, A.H.; Byrne, T.G. (1966) Chemical control of Pythium root rot in ornamentals with Dexon and Terrazole. California Agricultur

20(5):14-15.

5009249 Westerman, R.L.; Tucker, B.B. (1977) An evaluation of the effectiveness of Terrazole as a nitrification inhibitor when urea is applied to g

16,~In~Oklahoma Agricultural Experiment Station Research Report No. 758. Stillwater, Okla.: Oklahoma State University, Agricultu

122-2 Aquatic plant growth

MRID Citation Reference

42834606 Hoberg, J. (1993) Terrazole Technical--The Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: Amended Final Repo

4757: 41.1292.6133.430. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42834607 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Freshwater Blue-Green Alga, Anabaena flos-aquae: Final Report: Lab Project

Number: 93-3-4710: 41.1292.6136.420. Unpublished study prepared by Springborn Labs, Inc. 61 p.

42834608 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Freshwater Diatom, Navicula peliculosa: Amended Final Report: Lab Project

Number: 93-5-4763: 41.1292.6134.440. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42834609 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Marine Diatom, Skeletonema costatum: Final Report: Lab Project Number: 93

4742: 41.1292.6135.450. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42834610 Hoberg, J. (1993) Terrazole Technical--Toxicity to Duckweed, Lemna gibba: Final Report: Lab Project Number: 93-4-4714:

41.1292.6137.410. Unpublished study prepared by Springborn Labs, Inc. 63 p.

123-2 Aquatic plant growth

MRID Citation Reference
https://w2032pcctr562.aa.ad.epa.gov:8080/pls/prism10p/OPP_STUDY_Result.ST_Bibliography_Print 

42834606 Hoberg, J. (1993) Terrazole Technical--The Toxicity to the Freshwater Green Alga, Pseudokirchneriella subcapitata formerl

Amended Final Report: Lab Project Number: 93-5-4757: 41.1292.6133.430. Unpublished study prepared by Springborn Labs, I

42834607 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Freshwater Blue-Green Alga, Anabaena flos-aquae: Final Report: Lab Project

Number: 93-3-4710: 41.1292.6136.420. Unpublished study prepared by Springborn Labs, Inc. 61 p.

42834608 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Freshwater Diatom, Navicula pel iculosa: Amended Final Report: Lab Project

Number: 93-5-4763: 41.1292.6134.440. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42834609 Hoberg, J. (1993) Terrazole Technical--Toxicity to the Marine Diatom, Skeletonema costatum: Final Report: Lab Project Number: 93

4742: 41.1292.6135.450. Unpublished study prepared by Springborn Labs, Inc. 62 p.

42834610 Hoberg, J. (1993) Terrazole Technical--Toxicity to Duckweed, Lemna gibba: Final Report: Lab Project Number: 93-4-4714:

41.1292.6137.410. Unpublished study prepared by Springborn Labs, Inc. 63 p.

132-1 Dissipation of Dislodgeable Foliar & Soil Residues

MRID Citation Reference

44227801 Belcher, T.; Schuster, L.; Korpalski, S. (1997) Greenhouse Worker Reentry Exposure to Etridiazole: Lab Project Number: 96629: RP

96017: ABC/CA-174. Unpublished study prepared by ABC Labs. California. 326 p.

133-4 Inhal. passive dosimetry expo

MRID Citation Reference

40350501 Nigg, H.; Stamper, J.; Mahon, W. (1987) Pesticide Exposure to Florida Greenhouse Applicators: CR-810743. Unpublished study pr

Florida. 111 p.

43666001 Lunchick, C. (1995) Assessment of Worker Exposure and Potential Risk for Ornamental and Turf Uses of Etradiazole (sic). Unpublish

Schwartz & Connolly, Inc. 129 p.
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43717901 Lunchick, C. (1995) Assessment of Worker Exposure and Potential Risk for the Treatment of Cotton with Etradiazole. Unpublishe

Uniroyal Chemical Co., Inc. 68 p.

44227801 Belcher, T.; Schuster, L.; Korpalski, S. (1997) Greenhouse Worker Reentry Exposure to Etridiazole: Lab Project Number: 96629

96017: ABC/CA-174. Unpublished study prepared by ABC Labs. California. 326 p.
Appendix B. Complete Summary of Toxicity Endpoints for Etridiazole and 

Degradates. 

Table B1. Ecotoxicity Profile for Etridiazole. 

Group Species 

(Common Name) 

Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID or Acc. No. 

(Study 

Classification) 

Aquatic Organisms 

Freshwater 

Fish§

Oncorhynchus mykiss 

(Rainbow Trout) 

LC50 

(96 hours) 

1,210 μg a.i./L

(Mortality) 

0001703 

(Acceptable) 

2,410 μg a.i./L

(Mortality) 

45774802 

(Supplemental) 

NOAEC 

(60 days posthatch) 

120 μg a.i./L 

 (Larval weight) 

42834604 

(Supplemental) 

Freshwater 

Invertebrates 

Daphnia magna 

(Water Flea) 

EC50

(48 hours) 

3,080 μg a.i./L 

(Immobility) 

45774801 

(Acceptable) 

4,900 μg a.i./L 

(Immobility) 

00062427 

(Supplemental) 

NOAEC 

(21 days) 

370 μg a.i./L 

(Dry weight) 

42834605 

(Acceptable) 

Estuarine/ 

Marine Fish 

Cyprinodon variegatus 

(sheepshead minnow) 

LC50 

(96 hours) 

4,000 μg a.i./L 

 (Mortality) 

4283601 

(Acceptable) 

NOAEC 

(28 days posthatch) 

Data Gap N/A 

Estuarine/ 

Marine 

Invertebrates 

Crassostrea virginica 

(eastern oyster)

EC50

(96 hours) 

2,600 μg a.i./L 

 (Shell Deposition) 

4234602 

(Supplemental) 

Americamysis bahia 

(mysid shrimp)

LC50

(96 hours) 

2,500 μg a.i./L 

 (Mortality) 

42834603 

(Acceptable) 

Americamysis bahia 

(mysid shrimp)

NOAEC 

(28 days) Data Gap N/A 

Vascular Plants Lemna gibba 

(duckweed) 

IC50

(14 days) 

8,120 μg a.i./L 

 (Frond number) 

42834610 

(Supplemental – 

Data Gap) NOAEC 

(14 days) 

1,400 μg a.i./L 

(Frond number) 

Nonvascular 

Plants 

Raphidocelis 

subcapitata* 

(green algae) 

IC50

(120 hours) 

72 μg a.i./L 

(Cell density) 42834606 

(Acceptable) NOAEC 

(120 hours) 

2 μg a.i./L 

(Cell density) 

Anabaena flos-aquae 

(blue-green alga) 

IC50

(120 hours) 

290 μg a.i./L 

(Cell density) 

42834607 

(Acceptable) 
Group Species 

(Common Name) 

Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID or Acc. No. 

(Study 

Classification) 

NOAEC 

(120 hours) 

56 μg a.i./L 

(Cell density) 

Navicula pelliculosa

(freshwater diatom) 

IC50

(120 hours) 

430 μg a.i./L 

(Cell density) 42834608 

(Acceptable) NOAEC 

(120 hours) 

6.7 μg a.i./L 

(Cell density) 

Skeletonoma costatum

(marine diatom) 

IC50

(120 hours) 

245 μg a.i./L 

(Cell density) 42834609 

(Acceptable) NOAEC 

(120 hours) 

11 μg a.i./L 

(Cell density)

Terrestrial Organisms 

Avian‡

Colinus virginianus

(northern bobwhite 

quail) 

Oral LD50 

560 mg a.i./kg-bw 

(Survival) 

00002238 

(Acceptable) 

Dietary LC50 

(5 days) 

>5,000 mg/kg-diet 

(Survival) 

624780 

(Supplemental) 

NOAEC 

(27 weeks) 

50 mg/kg-diet 

(Hatchling viability) 

43744101 

(Supplemental) 

Anas platyrhynchos 

(mallard duck) 

Oral LD50 

1,640 mg a.i./kg-bw 

(Survival) 

0003276 

(Supplemental) 

Dietary LC50 

(5 days) 

1,650 mg/kg-diet 

(Survival) 

624790 

(Supplemental) 

NOAEC 

 (27 weeks) 

50 mg a.i./kg-diet†

(Female body weight) 

43774102 

(Supplemental) 

passerine Oral LD50 Data Gap N/A 

most sensitive species 

from oral toxicity tests Inhalation LC50 Data Gap N/A 

Mammals Rattus norvegicus

(laboratory rat) 

LD50 1028 mg a.i./kg-bw 43724501 

(Acceptable) 

NOAEL Data Gap N/A 

Inhalation LC50 >5.7 mg/L Acceptable 

(43724503) 

Terrestrial 

Invertebrates 

Apis mellifera 

(honey bee) 

LD50 

(48 hours) Data Gap N/A 

Plants 

(Vegetative 

Vigor) 

Dicots IC25

Data Gap (TEP) N/A NOAEC 

Monocots IC25

NOAEC 

Plants 

(Seedling 

Emergence) 

Dicots IC25

Data Gap (TEP) N/A NOAEC 

Monocots IC25

NOAEC 

§ Birds are surrogates for terrestrial-phase amphibians and reptiles. 

¶

 Freshwater are surrogates for aquatic-phase amphibians 

* Formerly Pseudokirchneriella subcapitata and Selenastrum capricornutum.
Table B2. Summary of Degradate Toxicity Data 

Group Species Endpoint 

(Duration) 

Toxicity Value 

 (Measured Effect) 

MRID 

(Study 

Classification) 

5-ethxy-3-dichloromethyl-1,2,4-thiadiazole (3-DCMT) 

Freshwater fish Onchorynchus mykiss LC50

(96 hours) 770 μg 3-DCMT/L 44606702 

(Acceptable) 

Freshwater 

invertebrates Daphnia magna 

EC50

(48 Hours) 1,100 μg 3-DCMT/L 45369401 

(Acceptable) 

Estuarine/marine 

fish 

Cyprinodon 

variegatus 

LC50

(96 hours) Data Gap (Degradate) N/A 

5-ethoxy-1,2,4-thiadiazole-3-carboxylic acid (3-Carb-T) 

Freshwater fish Onchorynchus mykiss LC50

(96 hours) Data Gap (Degradate) N/A 

Freshwater 

invertebrates Daphnia magna EC50(48 Hours) Data Gap (Degradate) N/A 

 
Appendix C. Results from the Screening Tool for Inhalation Risk Assessment 

(STIR) 
Appendix D. Results from Screening Imbibition Program (SIP) 
Appendix E. Data Call-In Recommendations and Justification Tables for Select 

Studies 

Justification tables are not provided for studies which are well-documented in existing 

US EPA test guidelines. 

With etridiazole technical grade active ingredient (TGAI): 

 Acute oral toxicity to passerine birds (OCSPP Guideline 850.2100) 

 Acute contact toxicity to honey bee (OCSPP Guideline 850.3020) 

 Acute oral toxicity to honey bee (e.g., OECD 213) 

 Larval toxicity to honey bee (e.g., OECD 237, requires protocol submission) 

 Freshwater fish full life cycle test (OCSPP Guideline 850.1500, requires protocol 

submission) 

 Fish early life stage test (estuarine/marine species) (OCSPP Guideline 850.1400) 

 Mysid chronic toxicity test (OCSPP Guideline 850.1350) 

 Environmental Chemistry Methods (ECM) for Soil and Water and Associated 

Independent Laboratory Validation (ILV), OCSPP Guideline 850.6100 is needed 

to support field dissipation studies. 

 Aerobic aquatic metabolism study, OCSPP Guideline 835.4300. 

With etridiazole typical end-use product (TEP): 

 Terrestrial plants seedling emergence and seedling growth (OCSPP Guideline 

850.4100) 

 Terrestrial plants vegetative vigor (OCSPP Guideline 850.4150)

 Aquatic plant toxicity test using Lemna ssp. (OCSPP 850.4400)

With etridiazole transformation products: 

 Acute toxicity to estuarine/marine fish using the degradate 3-DCMT (Guideline 72-

3, OCSPP Guideline 850.1075) 

 Acute toxicity to freshwater fish using the degradate 3-Carb-T (Guideline 72-1, 

OCSPP Guideline 850.1075) 

 Acute toxicity to freshwater invertebrates using the degradate 3-Carb-T (Guideline 

72-2, OCSPP Guideline 850.1010) 

Guideline Number: 850.2100 

Study Title: Avian Acute Oral Toxicity Test 

Test Substance: Etridiazole—TGAI 

Rationale for Requiring the Data 

Acceptable acute avian oral toxicity data were not submitted for a passerine species exposed to 

etridiazole, which is now required under the 40 CFR Part 158 (CFR 40 2008) data 

requirements for conventional pesticides. The revised Part 158 data requirements specify that 

acute avian oral toxicity data be submitted for either one waterfowl or one upland game 

species and one passerine species. The available acute oral toxicity data for bobwhite quail, 

when compared to estimated environmental concentrations, indicate that levels of concern are 
exceeded for birds on an acute exposure basis. Because passerine species have higher 

metabolic rates due to their smaller sizes than either waterfowl or upland game bird species 

and because they may utilize different metabolic pathways, they may be more or less sensitive 

to etridiazole. In order to properly characterize risk to passerines, an avian oral toxicity test is 

required for passerine birds. At this time, it is recommended that a passerine study protocol be 

submitted for review by the Agency prior to initiation of the study. 

Practical Utility of the Data 

How will the data be used? 

Acute avian oral toxicity data for passerine species will be used to refine the screening-level 

risk assessment by determining whether there are differences in avian species sensitivity to 

etridiazole between currently tested passerine and upland game and waterfowl species that are 

beyond the simple allometric predictions currently employed in the absence of such passerine 

data. The current extrapolation method may be under- or over-estimating risks to passerines. 

How could the data impact the Agency’s future decision-making? 

If future risk assessments, including listed species assessments, are performed without these 

data, the Agency would have to assume that etridiazole “may affect” listed birds directly (and 

listed species from other taxa indirectly), and use of etridiazole and its formulated products 

may need to be restricted in areas where listed species could be exposed. The lack of these data 

will limit the flexibility the Agency and registrants have in complying with the Endangered 

Species Act and could result in restrictions for etridiazole use that might prove to be 

unnecessary given data to address this area of uncertainty. In addition, the lack of these data 

may result in an uncertain assumed risk and potential mitigation of etridiazole formulations 

under FIFRA. 

Study Title: Honey Bee Acute Oral Toxicity Test 

Guideline Number: Non-guideline 

Test Substance: Etridiazole—TGAI

Rationale for Requiring the Data

No data are available to assess the toxicity of etridiazole to honey bees on an acute exposure 

basis. Based on the registered use patterns, terrestrial invertebrates have the potential to be 

exposed by contacting and consuming etridiazole residues. Therefore, the acute oral toxicity 

test is needed for EFED’s current screening-level process for assessing potential effects to 

terrestrial invertebrates. 

The Agency does not have a guideline for the acute oral honey bee study; however, the OECD 

213 guideline may be useful in protocol development. 

Practical Utility of the Data 

How will the data be used? Data will be used to assess hazard and characterize risk to nontarget listed and nonlisted terrestrial invertebrate species. 

How could the data impact the Agency’s future decision-making? If future endangered 

species risk assessments are performed without these data, the Agency would have to assume 

that etridiazole "may affect" endangered terrestrial insects directly (and endangered species 

from other taxa indirectly), and use of etridiazole might need to be restricted in areas where 

endangered species could be exposed. The lack of these data will limit the flexibility the 
Agency and registrants have in coming into compliance with the Endangered Species Act and 

could result in use restrictions for etridiazole which are unnecessarily severe. In addition, the 

lack of these data may result in an uncertain assumed risk and potential mitigation of 

etridiazole formulations under FIFRA. 

Study Title: Honeybee Larval Toxicity Study 

Guideline Number: Non-guideline 

Test Substance: Etridiazole—TGAI 

Rationale for Requiring the Data 

No data have been submitted on the toxicity of etridiazole to honey bee larvae. A larval 

toxicity study is needed to determine the toxicity of the compound to developing brood (i.e., 

larvae and pupae). This study is part of EFED’s current screening-level process for 

determining potential effects to terrestrial invertebrates. Therefore, a non-guideline honeybee 

larval toxicity study is recommended. The registrant should submit a proposed protocol for 

review and approval by EFED prior to initiation of the study.

Practical Utility of the Data 

How will the data be used? 

Data will be used to assess risk to non-target listed and non-listed terrestrial invertebrate 

species. This study would allow the Agency to refine the screening-level hazard assessment for 

beneficial terrestrial invertebrates. The effects data will be used to determine the potential for 

adverse effects on beneficial terrestrial invertebrates through direct effects on larval bees. 

How could the data impact the Agency’s future decision-making? 

EPA is required by section 7(a)(2) of the Endangered Species Act (ESA) to ensure that any 

action it authorizes or takes “...is not likely to jeopardize the continued existence of any 

endangered or threatened species or result in the destruction or adverse modification of 

critical habitat” and “to use the best scientific data available” in carrying out this obligation. 

The data EPA intends to call in are necessary to inform the determination required by ESA as 

to whether continued registration of a pesticide is or is not likely to jeopardize the species or 

its designated critical habitat. The lack of these data will limit the flexibility that the Agency 

has in coming into compliance with ESA and could result in use restrictions that are 

unnecessarily severe. In addition, the lack of these data may result in an uncertain assumed 

risk and potential mitigation of etridiazole formulations under FIFRA.