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EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

EPA Registration Division contact: Reuben Baris, PM 25, 703-305-7356

Gowan Company

5F8355

EPA has received a pesticide petition (5F8355) from [Gowan Company, LLC, 

P.O. Box 556 Yuma, AZ 85366, proposing, pursuant to section 408(d) of the Federal 

Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180.

by establishing a tolerance for residues of

EPTC, (S-ethyl dipropylthiocarbamate) in or on the raw agricultural 

commodity Grass, grown for seed, forage at 0.6 parts per million (ppm) and Grass, 

grown for seed, hay at 0.5 ppm. EPA has determined that the petition contains data or

information regarding the elements set forth in section 408 (d)(2) of FDDCA; however, 

EPA has not fully evaluated the sufficiency of the submitted data at this time or whether 

the data supports granting of the petition. Additional data may be needed before EPA 

rules on the petition.

A. Residue Chemistry

1. Plant metabolism. EPTC is systemic and is rapidly metabolized in plants 

into numerous products. The Agency has determined that EPTC and three hydroxy

metabolites will serve as markers to represent EPTC residues in plants. 

2. Analytical method. Adequate methods are available for the determination of 

EPTC and three hydroxy metabolites in grass grown for seed. EPTC is analyzed by 

extraction of the samples with toluene with subsequent quantification using gas 

chromatography with nitrogen-phosphorus detection. The three hydroxy 

metabolites are extracted from the samples with a mixture of acetone and water. 

The acetone is dispelled and the aqueous fraction is digested with acid. The 

hydrolyzed metabolites are then extracted with a mixture of hexane and ether, and 

the extract is purified through a solid phase extraction cartridge. The residues are 

then derived and quantified using a gas chromatograph equipped with a massselective detector. The Limit of Quantification (LOQ) for EPTC was 0.05 ppm and 

0.01 ppm for the hydroxy metabolites. 

3. Magnitude of residues. Residues of EPTC and hydroxy metabolites ranged 
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from <LOQ (0.0286 ppm) to 0.152 ppm on six ryegrass forage RAC samples 

collected 29-30 DAA application. A permanent tolerance of grass grown for seed in 

grass, hay, of 0.5 ppm and grass, forage, of 0.6 ppm is proposed. 

B. Toxicological Profile

1. Acute toxicity. EPTC is moderately toxic (Toxicity Category III) via the 

oral and dermal routes, and in primary eye irritation study in rabbits, the technical 

product was found to be slightly irritating (Toxicity Category III). EPTC is most 

toxic via the inhalation route (Toxicity Category II). 

2. Genotoxicty. Testing of EPTC for genotoxicity through an in vivo and in 

vitro assays indicated no concern. 

3. Reproductive and developmental toxicity. Studies in rats and rabbits showed 

developmental and reproductive toxicity only in the presence of maternal or 

parental toxicity. In a prenatal developmental toxicity study in rats, developmental 

toxicity (in part, decreased fetal body weights and decreased litter size, but effects 

were attributed to maternal stress) was seen in the presence of marked maternal 

toxicity (increased mortality and decreased body weight). In developmental toxicity 

study in rabbits, developmental toxicity (decrease fetal body weight) was again seen 

in the presence of marked maternal toxicity (in part, decreased body weight and 

increased mortality). In a two generation reproduction test in rats, effects in the 

offspring were observed only at or above treatment levels which resulted in parental 

toxicity. 

4. Subchronic toxicity. Cardiotoxicity and neurotoxicity were observed in 

subchronic studies in rats. Cardiotoxicity was attributed to myocardial 

degeneration by histological exam. The acute neurotoxicity study in the hen did not 

show neurotoxicity, however. 

5. Chronic toxicity. Chronic testing in rats and dogs also showed 

cardiotoxicity and neurotoxicity. 

6. Animal metabolism. A study in rats indicated that EPTC was rapidly 

absorbed and excreted via radiolabeled product. Study indicates that only 1.2% of 

radiolabeled product was present in tissues after 7 days. 

7. Metabolite toxicology. The Agency has determined that metabolites 

incorporating the thiocarbamate moiety are of concern. These residues include 

various acid conjugates. 

8. Endocrine disruption. Per the Tier I test battery of the EDSP established by 

the Agency, EPTC does not indicate any endocrine disruptor effects. 

C. Aggregate Exposure

1. Dietary exposure. Tolerances have been established in the 40 CFR 180.117 
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for the residues of EPTC in or on a variety of raw agricultural commodities. Risk 

assessments were performed to assess dietary exposures from EPTC in food as 

follows: 

i. Food. Results of the aggregate dietary exposure assessment for all uses 

indicate that the estimated risks are below the level of concern for both acute and 

chronic dietary per the following EPA document, EPTC: Registration Review 

Scoping Document for Human Health Assessment, March 5, 2013, DP Barcode 

D405957, pg 2 of 23. 

ii. Drinking water. Estimation of drinking water levels for EPTC did not 

result in levels of concern. 

2. Non-dietary exposure. Exposures by non-dietary means were determined to 

be not of concern in the EPTC RED. 

D. Cumulative Effects

The Agency has determined that thiocarbamates cannot be regulated as a 

single class due to differing neurotoxic activity patterns. Due to incomplete 

information regarding developmental neurotoxicity, EPA has retained the 10X 

FQPA Safety Factor. 

E. Safety Determination

1. U.S. population. The proposed grass for seed use of EPTC results in 

exposures to the general population and all subpopulations that are within 

acceptable ranges. 

2. Infants and children. [Risk calculations for the proposed grass for seed use 

result in acceptable exposures. The Agency retained a 10X Safety Factor in the 

toxicological endpoints for EPTC which was included in the calculation of 

exposures. 

F. International Tolerances

There are no international Tolerances/MRLs currently established for 

EPTC.