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EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

EPA Registration Division contact: [PV Shah, (703) 308-1846]

INSTRUCTIONS: Please utilize this outline in preparing the pesticide petition. In 

cases where the outline element does not apply, please insert “NA-Remove” and 

maintain the outline. Please do not change the margins, font, or format in your 

pesticide petition. Simply replace the instructions that appear in green, i.e., “[insert 

company name],” with the information specific to your action.

TEMPLATE:

Taminco US Inc., a subsidiary of Eastman Chemical Company

IN-10854

EPA has received a pesticide petition (IN-10854) from SciReg Inc. (12733 

Director’s Loop, Woodbridge, VA 22192) on behalf of Taminco US Inc., a 

subsidiary of Eastman Chemical Company, [Two Windsor Plaza, Suite 400, 7450 

Windsor Drive, Allentown, PA 18195] 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 180.920 to establish an exemption from the requirement of a tolerance for [2-

Pyrrolidinone, 1-butyl- (CAS No. 3470-98-2) under 40 CFR 180.920 when used as an 

inert ingredient (solvent/co-solvent) in pesticide formulations]. 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.

2. Analytical method. [Taminco is requesting that 2-Pyrrolidinone, 1-butyl- be 

exempt from the requirement of a tolerance under 40 CFR 180.920. Therefore, 

Taminco believes that an analytical method to determine residues in treated crops is 

not relevant.]

3. Magnitude of residues. [Taminco is requesting that 2-Pyrrolidinone, 1-

butyl- be exempt from the requirement of a tolerance under 40 CFR 180.920. 

Therefore, Taminco believes that data on the magnitude of residues in treated crops 

is not relevant.]
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B. Toxicological Profile

1. Acute toxicity. [Acute Oral Toxicity

2-Pyrrolidinone, 1-butyl- was tested for acute oral toxicity in WIST (SPF) rats 

according to OECD Guideline No. 423 and in compliance with the Swiss Ordinance 

relating to Good Laboratory Practice which is based on OECD Good Laboratory 

Practice.

Three female RccHan: WIST (SPF) rats were treated with the test item, 

2-Pyrrolidinone, 1-butyl-, by oral gavage at a dose of 2,000 mg/kg body weight and 

two further groups of three females each were treated with 300 mg/kg body weight 

of the test item. The test item was formulated in purified water at a concentration of 

0.2 g/mL and 0.03 g/mL and administered at a dose volume of 10 mL/kg. 

All animals were examined for clinical signs approximately 30 minutes after 

treatment and again at approximately 1, 2, 3, and 5 hours after treatment on Day 1, 

and once daily during test Days 2 - 15. Mortality/viability was recorded together 

with clinical signs twice daily during Days 2 - 15. Body weights were recorded on 

Day 1 (prior to administration) and on Days 8 and 15. All animals were necropsied 

and examined macroscopically.

All animals treated with 300 mg/kg of 2-Pyrrolidinone, 1-butyl- survived until the 

end of the study period. Two females treated with 2,000 mg/kg of the test item died 

after the administration and one of them was sacrificed in extremis also on the day 

of treatment. The females treated with 2,000 mg/kg showed shortly after treatment 

moderate convulsions, tachypnea, prostration, clear lacrimation in both eyes, and 

were found unconscious; two of them were found dead later. The females treated 

with 300 mg/kg of the test item had slightly to moderately decreased activity and 

slightly ruffled fur. The three further females treated with 300 mg/kg had no clinical 

signs. No clinical signs were observed during Days 2 to 15. The body weight of the 

animals was within the range commonly recorded for this strain and age. No 

macroscopic findings were recorded at necropsy. The median lethal dose of 2-

Pyrrolidinone, 1-butyl- after single oral administration to female rats, observed over 

a period of 14 days is: 300 mg/kg body weight < LD50 (female rat) < 2,000 mg/kg 

body weight.

Acute Dermal Toxicity

The test item, 2-Pyrrolidinone, 1-butyl-, was tested for acute dermal toxicity in 

Wistar (RccHanTM:WIST) rats according to OECD Guideline No. 402 and in 

compliance with OECD Good Laboratory Practice. 

Initially, two animals (one male and one female) were given a single, 24 hour, semioccluded dermal application of the undiluted test item to intact skin at a dose level 

of 2,000 mg/kg body weight. Based on the results of the initial test, a further group 

of eight animals (four males and four females) were similarly treated. Clinical signs 
3

and body weight development were monitored during the study. The test sites were 

examined for evidence of primary irritation once daily for fourteen days. All 

animals were subjected to gross necropsy. 

There were no deaths and no signs of systemic toxicity. Very slight erythema was 

noted at the test sites of two females. Small superficial scattered scabs and glossy 

skin were also noted at the test site of one female. No other signs of dermal irritation 

were noted. Animals showed expected gains in body weight except for two females 

which showed no gain in body weight or body weight loss during the first week with 

expected gain in body weight during the second week. No abnormalities were noted 

at necropsy. Therefore, the acute dermal LD50 for 2-Pyrrolidinone, 1-butyl- was 

greater than 2,000 mg/kg body weight.

Primary Eye Irritation

2-Pyrrolidinone, 1-butyl- was tested for acute ocular irritation in three male New 

Zealand White rabbits according to EPA Guideline OPPTS 870.2400 and in 

compliance with EPA (40 CFR Parts 160 and 792) and OECD Good Laboratory 

Practice. 

Each of three rabbits received a single 0.1 mL dose of the test substance, 2-

Pyrrolidinone, 1-butyl-, in the conjunctival sac of the right eye. The contralateral 

eye of each animal remained untreated and served as a control. Test and control 

eyes were examined for signs of irritation for up to 10 days following dosing. 

Animals were observed for general health/mortality and moribundity twice daily 

throughout the study.

Exposure to the test article produced corneal opacity in 1/3 test eyes by the 24 hour 

scoring interval and complete resolution occurred by the Day 7 scoring interval. 

Iritis was observed in 1/3 test eyes by the 1 hour scoring interval and in 2/3 test eyes 

by the 24 hour scoring interval. Complete resolution of the iritis occurred in 1/3 test 

eyes by the Day 7 scoring interval and in 2/3 test eyes by the Day 10 scoring interval. 

Conjunctivitis (redness, swelling, and/or discharge) occurred in 3/3 test eyes by the 1 

hour scoring interval and complete resolution occurred in 1/3 test eyes by the Day 7 

scoring interval and in 2/3 test eyes by the Day 10 scoring interval. An additional 

ocular finding of neovascularization (2/3 test eyes) was noted during the study. 

Decreased fecal output was observed in all animals. This observation, which is a 

known pharmacological effect of opioids, was likely due to the buprenorphine 

treatment that the animals received from Days 0 to 5. According to the Kay and 

Calandra Evaluation Criteria, 2-Pyrrolidinone, 1-butyl- is considered to be a 

moderate irritant to the ocular tissue of the rabbit.

Primary Dermal Irritation

2-Pyrrolidinone, 1-butyl- was tested for acute skin irritation in three male New 

Zealand White rabbits according to EPA Guideline OPPTS 870.2500 and in 
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compliance with EPA (40 CFR Parts 160 and 792) and OECD Good Laboratory 

Practice. 

Each of three rabbits received a 0.5 mL dose of the test substance, 2-Pyrrolidinone, 

1-butyl-, as a single dermal application. The dose was held in contact with the skin 

under a semi-occlusive binder for exposure periods of 3 minutes, 1 hour, and 4 

hours for one animal and an exposure period of 4 hours for two animals. Following 

the completion of each exposure period, the binder was removed and the remaining 

test substance was wiped from the skin using gauze moistened with deionized water 

followed by dry gauze. Test sites were subsequently examined and scored for dermal 

irritation for up to 21 days following patch removal. 

Three-Minute Exposure: Exposure to the test substance produced no erythema or 

edema through 72 hours postdose; however, very slight erythema was noted at the 

single test site on Day 14, which subsequently resolved by Day 21.

One-Hour Exposure: Exposure to the test substance produced very slight erythema 

at the single test site immediately after patch removal. The dermal irritation was not 

observed at the 1-hour scoring interval, but was present again at the 24-, 48-, and 

72-hour scoring intervals. The dermal irritation was not observed on Day 7, but was 

observed again on Day 14. Day 21 scoring revealed no irritation. Additional dermal 

findings included desquamation.

Four-Hour Exposure: Exposure to the test substance produced very slight erythema 

at 3/3 test sites and very slight edema at 1/3 test sites by the 1-hour scoring interval. 

Well-defined erythema was observed in 1/3 test sites at the 24-, 48-, and 72-hour 

scoring intervals. The dermal irritation was not observed in 1/3 test sites on Day 7, 

but was again observed in that animal on Day 10. Dermal irritation did not resolve 

completely in the remaining two test sites. Additional dermal findings included 

blanching (focal and/or pinpoint areas up to 10% of the test site) in 1/3 test sites and 

desquamation in 3/3 test sites. Under the conditions of the test (4-hour exposure), 2-

Pyrrolidinone, 1-butyl- is considered to be a slight irritant to the skin of the rabbit. 

The calculated Primary Irritation Index (P.I.I.) for the test substance was 1.33.

Dermal Sensitization

Two dermal sensitization studies were conducted with 2-Pyrrolidinone, 1-butyl-. 

Taminco is relying on the second study for the following reasons. A local lymph 

node assay in mice was previously conducted at LPT Laboratory of Pharmacology 

and Toxicology GmbH & Co. KG (“LPT”) in April 2013. Subsequent review of this 

study revealed significant deviations from the OECD Guideline 429, as well as 

significant concerns with the quality of the work. Per the Guideline, a laboratory 

may deviate from a requirement when there is a valid reason which should be stated 

and supported in the final report. In the case of the LPT Study, there were a 

number of significant deviations from the Guideline that were not supported in the 

final report including, but not limited to the following:
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• Use of lymph node weight as the metric for cellular proliferation instead of 

more sensitive metrics such as radiolabeled thymidine as prescribed by the 

Guideline or flow cytometric analysis of isolated cells.

• Use of a customized Stimulation Index instead of the index specified by the 

Guideline.

• Study duration of four days instead of six days as specified by the Guideline.

Each of these deviations from the Guideline is significant and was not justified by 

the laboratory. Moreover, Taminco does not believe that any of these deviations 

were necessary and that the test article could have been accurately assessed within 

the requirements of the Guideline.

Taminco also has significant concerns with the quality of the work performed by 

LBT. The most conspicuous example involves the reproducibility of the results 

wherein certain concentrations of the test article that were not irritating in the 

range finder were subsequently found to be irritating in the actual study. The 

inability of the laboratory to reproduce findings for a simple endpoint raises 

significant concerns regarding the quality of work done in performance of this 

study.

Given the significant deviations from the Guideline and the concerns regarding the 

quality of the work, Taminco conducted another local lymph node assay in the 

mouse in accordance with the Guideline OECD 429, and wishes to rely on the 

results of this study to support the tolerance exemption for 2-Pyrrolidinone, 1-butyl-

. Both dermal sensitization studies are summarized below.

Dermal Sensitization Study #1

The test item, 2-Pyrrolidinone, 1-butyl-, was assessed for skin sensitization potential 

in female NMRI mice, using the local lymph node assay.

This study did not employ the use of radioactive labelling to measure cell 

proliferation. An alternative method was used employing lymph node weight and 

lymph node cell count. This method was established by a European interlaboratory 

validation exercise. In addition, the acute inflammatory skin reaction was measured 

by ear weight determination of circular biopsies of the ears and ear thickness 

measurements on test day one and test day four to identify skin irritation properties 

of the test item. Values above 1.4 (lymph node cell count to identify sensitisation) or 

1.1 (ear weight to identify irritation) were considered positive.

Five concentrations of the test item (1%, 5%, 10%, 25%, and 50% w/w) diluted 

with acetone/olive oil (3+1 v/v) were tested in six female NMRI mice per group and 

compared to a vehicle control group. In addition, a positive control group [25% 

solution v/v of α-hexyl cinnamic aldehyde in acetone/olive oil (3+1 v/v)] was tested.
6

The positive control group caused the expected increases in lymph node cell count 

and lymph node weight (statistically significant at p ≤ 0.01). Therefore, the study 

was regarded as valid.

Treatment with 2-Pyrrolidinone, 1-butyl- at concentrations of 1% and 5% did not 

reveal statistically significant increased values for lymph node cell count and lymph 

node weight. The stimulation indices of the lymph node cell count did not exceed the 

threshold level of 1.4. Therefore, the test item was classified as not sensitizing. The 

threshold level for the ear weight of 1.1 was not exceeded and no increase of ear 

thickness was observed.

Treatment with 2-Pyrrolidinone, 1-butyl- at concentrations of 10, 25, and 50% 

(w/w) revealed statistically significant increased values (p ≤ 0.01 or p ≤ 0.05) for 

lymph node cell count and lymph node weight. However, ear weights were also 

significantly increased at these concentrations pointing to strongly irritating 

properties on the mouse ear. The stimulation indices of the lymph node cell count 

(sensitizing properties) and ear weight (irritation properties) exceeded the threshold 

levels of 1.4 or 1.1.

No signs of local or systemic intolerance were recorded. Body weight was not 

affected by the treatment. 

2-Pyrrolidinone, 1-butyl- did not reveal any sensitizing properties in the local lymph 

node assay at concentrations of 1% or 5% (w/w) in acetone/olive oil (3 + 1 v/v). 

Concentrations of 10% or higher did not permit an evaluation due to the irritating 

properties of the test item shown through increased ear weight and an increase in 

ear thickness.

Dermal Sensitization Study #2

The test item, 2-Pyrrolidinone, 1-butyl-, was assessed for skin sensitization potential 

in CBA/Ca strain mice using the local lymph node assay according to OECD 

Guideline 429 and in compliance with OECD Good Laboratory Practice. 

Following a preliminary screening test in which no clinical signs of toxicity were 

noted at a concentration of 50% v/v, this concentration was selected as the highest 

dose investigated in the main test of the local lymph node assay. Three groups, each 

of five animals, were treated with 50 μL (25 μL per ear) of the test item as a solution 

in acetone/olive oil 4:1 at concentrations of 50%, 25% or 10% v/v. A further group 

of five animals was treated with acetone/olive oil 4:1 alone. A concurrent positive 

control test, using a group of five animals, was also performed with the known 

sensitizer, a-Hexylcinnamaldehyde tech., 85%, at a concentration of 25% v/v in 

acetone/olive oil 4:1. The test item was applied topically to the dorsal surface of the 

ear. 

The Stimulation Index expressed as the mean radioactive incorporation for each 
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treatment group divided by the mean radioactive incorporation of the vehicle 

control group was as follows: 0.70, 0.91, and 1.22 for the 10%, 25%, and 50% 

treatment groups, respectively. The Stimulation Index for the positive control was 

5.39.

Therefore, the test item was considered to be a non-sensitizer under the conditions 

of the test. a-Hexylcinnamaldehyde, tech., 85% gave a Stimulation Index of greater 

than 3 when tested at a concentration of 25% v/v in acetone/olive oil 4:1.]

2. Genotoxicty. [Bacterial Reverse Mutation Test

The mutagenic potential of 2-Pyrrolidinone, 1-butyl- was assessed in the Salmonella 

typhimurium reverse mutation assay according to OECD Guideline 471 and in 

compliance with OECD Good Laboratory Practice.

Salmonella typhimurium strains TA98, TA100, TA102, TA1535, and TA1537 were 

tested in the presence and absence of metabolic activation from a microsomal 

preparation derived from Aroclor 1254-induced rat liver. The first experiment was 

carried out as a plate incorporation test and the second as a preincubation test. 

Doses ranged from 31.6 to 5,000 μg 2-Pyrrolidinone, 1-butyl-/plate.

2-Pyrrolidinone, 1-butyl- up to 5,000 μg/plate caused no mutagenic effects in the 

plate incorporation and preincubation tests, with or without metabolic activation.

In Vitro Mammalian Cell Gene Mutation Test

The mutagenic potential of the test item, 2-Pyrrolidinone, 1-butyl-, was assessed on 

the thymidine kinase, TK+/- locus of the L5178Y mouse lymphoma cell line 

according to OECD Guideline 476 and in compliance with OECD Good Laboratory 

Practice.

Two independent experiments were performed. In Experiment 1, L5178Y TK +/-

3.7.2c mouse lymphoma cells (heterozygous at the thymidine kinase locus) were 

treated with the test item at six dose levels, in duplicate, together with vehicle

(solvent) and positive controls using 4-hour exposure groups, both in the absence 

and presence of metabolic activation (2% S9). In Experiment 2, the cells were 

treated with the test item at six dose levels using a 4-hour exposure group in the 

presence of metabolic activation (1% S9) and a 24-hour exposure group in the 

absence of metabolic activation. The doses of test item used in both tests (44.1, 88.2, 

176.4, 352.8, 705.6, and 1,411.2 μg/mL) were selected following the results of a 

preliminary toxicity test. 

The maximum dose level used in the main test was the 10 mM Maximum 

Recommended Dose level. No precipitate of test item was observed. Negative 

(vehicle) and positive controls responded adequately. The study was, therefore, 

considered valid.
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2-Pyrrolidinone, 1-butyl- did not induce any toxicologically significant or doserelated (linear-trend) increases in the mutant frequency at any of the dose levels, 

either with or without metabolic activation, in either the first or the second 

experiment. Therefore, 2-Pyrrolidinone, 1-butyl- is considered to be non-mutagenic 

under the conditions of the test.

In Vitro Mammalian Cell Micronucleus Test

The clastogenic and aneugenic potential of the test item, 2-Pyrrolidinone, 1-butyl-, 

was tested on the nuclei of normal human lymphocytes according to OPPTS 

Guideline 870.5300 and in compliance with OECD Good Laboratory Practice.

Duplicate cultures of human lymphocytes, treated with the test item, were evaluated 

for micronuclei in binucleate cells at multiple dose levels, together with vehicle and 

positive controls. The dose levels (44.1, 88.2, 176.4, 352.8, 705.6, 1,411.2 μg/mL) were 

selected using data from a preliminary toxicity test. Experiment 1 used a 4-hour 

exposure in the presence and absence of a standard metabolizing system (2% S9). 

Experiment 2 used a 24-hour exposure in the absence of metabolic activation and 

was performed concurrently with the exposure groups of Experiment 1. At the end 

of the exposure period, the cell cultures were washed and then incubated for a 

further 28 hours in the presence of Cytochalasin B.

Negative (solvent) and positive controls responded adequately. The study was, 

therefore, considered valid.

2-Pyrrolidinone, 1-butyl- did not induce any statistically significant increases in the 

frequency of cells with micronuclei, in either of the two experiments, using a dose 

range that included the maximum recommended dose level. 2-Pyrrolidinone, 1-

butyl- was considered to be non-clastogenic and non-aneugenic to human 

lymphocytes in vitro.]

3. Reproductive and developmental toxicity. [Prenatal Development

Prenatal development was evaluated with the test item, 2-Pyrrolidinone, 1-butyl-, in 

accordance with OECD Guideline 414 and in compliance with OECD Good 

Laboratory Practice.

Pregnant Crl:CD(SD) rats were exposed to the test item or vehicle control (tap 

water) at concentrations of 0, 5, 50, or 500 mg/kg bw/day by oral gavage on Days 6 

to 19 of gestation. 

Animals were observed daily for mortality and clinical signs. Body weights were 

recorded on Day 0 of gestation and daily thereafter. Food consumption was 

measured daily. On Day 20 of gestation, rats were sacrificed and examined 

macroscopically. The gravid uterus weight was determined. The placenta was 

observed for focal indurations, number of fetuses (alive and dead), and number and 

size of resorptions. Corpora lutea in the ovaries, and implantations and location of 
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fetuses in the uterus were determined. Sex and viability of fetuses were also 

determined. Fetus weights and weights of the placentae were taken. Fetuses were 

examined for skeletal and soft tissue retardations, variations, or malformations.

No mortality was observed and no signs of toxicity were noted in dams treated with 

2-Pyrrolidinone, 1-butyl- up to 500 mg/kg bw/day. At 500 mg/kg bw/day, a slight, 

but statistically significant reduction in body weight was noted from gestation Day 7 

to gestation Day 20. Body weight gain was statistically significantly reduced in dams 

treated with 500 mg/kg bw/day between gestation Days 6 and 9. A statistically 

significant reduction in the net body weight change and absolute body weight 

change was noted for dams treated with 500 mg/kg bw/day from gestation Day 6 

until the day of necropsy. A reduction in food consumption was noted after the start 

of treatment on gestation Day 7 and on gestation Day 8 in dams treated with 500 

mg/kg bw/day. Thereafter, a normal level of food intake was reached. No 

macroscopic findings were noted. A reduced gravid uterus weight and carcass 

weight were noted at necropsy for dams treated with 500 mg/kg bw/day. No test 

item-related changes were noted for the number of corpora lutea, implantation sites, 

resorptions, and live and dead fetuses. The percentages of pre- and postimplantation loss were also not influenced by the test item. No dead fetuses and no 

test item-related influence on sex distribution were noted. No test item-related 

influence was noted on the mean placental weights or mean fetal weights per dam. 

No test item-related malformations, variations, or retardations were noted in the 

fetuses during external/internal examination, skeletal examination, and/or soft tissue 

evaluation. 

Therefore, the NOAEL for administration of 2-Pyrrolidinone, 1-butyl- was 

determined to be 50 mg/kg bw/day for the dams and greater than 500 mg/kg bw/day 

for the fetuses.

Benchmark Dose (BMD) Modeling Support for n-Butylpyrrolidone 

Toxicology Excellence for Risk Assessment (TERA) evaluated the critical effects of 

2-Pyrrolidinone, 1-butyl- in a range-finding and a prenatal developmental study in 

CD rats to 1) determine the key study with data appropriate for conducting 

benchmark dose (BMD) modeling, 2) identify the data for modeling, and 3) conduct 

the modeling. 

Initial modeling was conducted using the continuous models in U.S. EPA’s BMD 

modeling software (BMDS version 2.5.0) for the mean and individual data for fetal 

body weights and gravid uterine weights. A benchmark response (BMR) of 5%, the 

standard BMR for developmental toxicity studies was modeled along with one 

standard deviation for comparison. Several of the models for the BMR of 5% and 1 

standard deviation model runs fit the data well, and criteria for all of these models 

were comparable. The ranges of BMDs and benchmark dose model lower 

confidence limits (BMDLs) varied from 196 to 308 mg/kg-day. An average within 

these ranges would be an acceptable choice for a point of departure. For a BMR of 
10

one standard deviation, the average BMD is 394 mg/kg-day and the average BMDL 

is 250 mg/kg-day. For a BMR of 5%, the average BMD is 306 mg/kg-day and the 

average BMDL is 201 mg/kg-day. In this case, the BMDL of 201 mg/kg-day for a 

5% response is recommended because the modeling was based on a BMR of 5% 

decreased fetal body weight, which is more biologically appropriate than the use of 1 

standard deviation.]

4. Subchronic toxicity. [90-day Oral – rat

A subchronic oral toxicity study was conducted with the test item, 2-Pyrrolidinone, 

1-butyl-, according to OECD Guideline 408 and in compliance with OECD Good 

Laboratory Practice. 

Ten male and ten female Wistar HanTM:RccHanTM:WIST strain rats were assigned

to each dose level (0, 10, 100, and 500 mg/kg bw/day) and were administered vehicle 

(distilled water) or test item daily by oral gavage for ninety days. Animals were 

observed daily, and body weight, food consumption, and functional observations 

were recorded weekly for all animals. Estrous cycle was evaluated for all females 

during the last three weeks of the study. After 13 weeks of treatment, 

ophthalmoscopic exams were conducted on the control and high dose animals, and 

hematology and chemistry, were analyzed for all animals. At termination, all 

animals were sacrificed and necropsied. All animals were subject to macroscopic 

examination and select organ weights were taken. Males were also subject to sperm 

assessment. Microscopic examination was performed on select tissues from all 

animals in the control and high does groups. Also, the liver and thymus were 

examined from all animals in the low and intermediate dose groups, and the kidney 

was examined from males only in the low and intermediate dose groups.

No mortality was observed with treatment of 2-Pyrrolidinone, 1-butyl- up to 500 

mg/kg bw/day. Neither the type, incidence or distribution of clinical signs apparent 

indicated an adverse effect of treatment at 10, 100, or 500 mg/kg bw/day. There 

were no toxicologically significant changes in the behavioral parameters measured, 

functional performance or sensory reactivity at 10, 100, or 500 mg/kg bw/day. There 

were no adverse effects of treatment on body weight development, food consumption 

or food efficiency, or water consumption at 10, 100, or 500 mg/kg bw/day. There 

were no treatment-related ocular effects and no adverse effects were detected 

during the estrous cycle assessments or in sperm concentration, morphological 

assessments, or in homogenization-resistant spermatid counts. There were no 

toxicologically significant effects of treatment on the hematology parameters 

measured. Males treated with 500 mg/kg bw/day showed a statistically significant 

increase in total protein, calcium, creatinine, and bile acid, and a statistically 

significant reduction in albumin/globulin ratio. Females treated with 500 mg/kg 

bw/day showed a statistically significant reduction in albumin/globulin ratio, 

chloride, and alkaline phosphatase and a statistically significant increase in 

cholesterol, bilirubin, and bile acid. Males treated with 100 mg/kg bw/day showed a 

statistically significant increase in chloride. Eight males treated with 500 mg/kg 

bw/day had enlarged livers at necropsy. No toxicologically significant macroscopic 
11

findings were evident in females treated with 500 mg/kg bw/day or in animals of 

either sex treated with 10 or 100 mg/kg bw/day. Animals of either sex treated with 

500 mg/kg bw/day and males treated with 100 mg/kg bw/day had a statistically 

significant increase in kidney and liver weights, both absolute and relative to 

terminal body weight. No such effects were evident in females treated with 100 

mg/kg bw/day or animals of either sex treated with 10 mg/kg bw/day. Liver 

hypertrophy or centrilobular hypertrophy was observed in males and females 

treated with 500 mg/kg bw/day and in males treated with 100 mg/kg bw/day. An 

increase in incidence and severity of hyaline droplet accumulation, multifocal 

basophilic tubules (degenerating/regenerating), and the presence of proteinaceous 

casts in the tubules of kidneys of males were observed at 100 mg/kg bw/day and 

above. Minimal atrophy in the thymus was noted in males and females treated with 

500 mg/kg bw/day and in males treated with 100 mg/kg bw/day. Vacuolation in the 

adrenal cortex was present in males only at an increased incidence and severity at 

100 mg/kg bw/day and above. One male treated with 10 mg/kg bw/day had 

vacuolation above the expected level; however, the toxicological significance of this 

in only one male is equivocal.

Oral administration of 2-Pyrrolidinone, 1-butyl- to rats by gavage for a period of 

ninety consecutive days at dose levels of 10, 100, and 500 mg/kg bw/day resulted in 

treatment related effects in animals of either sex treated with 500 mg/kg bw/day and 

males treated with 100 mg/kg bw/day. The NOEL was considered to be 10 mg/kg 

bw/day for males and 100 mg/kg bw/day for females. The following effects were 

considered to be treatment-related and adaptive in nature and, therefore, not 

adverse: 1) the microscopic liver changes in animals of either sex treated with 500 

mg/kg bw/day and males treated with 100 mg/kg bw/day, and the associated blood 

chemistry changes identified in animals of either sex treated with 500 mg/kg bw/day 

were likely a represent an adaptive response to treatment and, therefore, considered 

not to represent a serious risk to health, 2) the microscopic changes in the adrenals 

of males treated with 500 and 100 mg/kg bw/day and the microscopic thymus 

changes are likely the result of the adaptive changes apparent in the liver or a 

secondary stress related response. In terms of extrapolation to man, and risk 

assessment calculations, the effects relating to renal changes in the male rat are 

species- and sex-specific and, therefore, are not relevant. For these reasons, the 

NOAEL was considered to be 500 mg/kg bw/day for animals of either sex.]

5. Chronic toxicity. [Carcinogenicity

The 90-day toxicity study in rats (Harlan Laboratories Ltd. Study No. 41303953; 

Volume 19) provided a basis for evaluation of the carcinogenic potential of 2-

Pyrrolidinone, 1-butyl-. In that study, the liver, kidney, thymus, and adrenals were 

target organs for toxicity. Evaluation of the database for n-methylpyrrolidone 

(NMP) shows similar target organ toxicity as 2-Pyrrolidinone, 1-butyl- and 1-

ethylpyrrolidin-2-one (NEP), as both chemicals are considered suitable surrogates 

for evaluation. Neither 2-Pyrrolidinone, 1-butyl-, n-methylpyrrolidone, nor 1-

ethylpyrrolidin-2-one was found to be genotoxic or mutagenic in a number of 

assays. In carcinogenicity studies, n-methylpyrrolidone was not carcinogenic in two 
12

year rat studies by the inhalation dietary routes. An increased incidence of liver 

adenomas and carcinomas were seen in mice exposed to a dietary level of nmethylpyrrolidone exceeding 1,000 mg/kg/day for 18 months. No tumors were seen 

at lower concentrations. Liver tumor induction in mice and its relevance to humans 

has been an area of great debate for decades. A mode of action study with

n-methylpyrrolidone at the high dose used in the mouse oncogenicity study strongly 

suggests that exposure to n-methylpyrrolidone at high concentrations leads to a 

mitogenic burst in the mouse liver that ultimately may lead to a tumorigenic 

response in the liver. This mode of action has been proposed for phenobarbital. 

Based on the lack of mutagenicity or genotoxicity and the similarity of

2-Pyrrolidinone, 1-butyl- to n-methylpyrrolidone, it can be concluded that 

2-Pyrrolidinone, 1-butyl- should not be considered as potentially carcinogenic. 

Further, liver changes seen in the studies were considered as adaptive, nonadverse 

findings. Kidney pathological lesions were consistent with hydrocarbon 

nephropathy in male rats induced by α-2-microglobulin accumulation, a finding 

that is considered as not relevant to humans. The only evidence of a tumorigenic 

response was seen at an exceedingly high dose in mice treated with 

n-methylpyrrolidone.]

6. Animal metabolism. [NA-Remove.]

7. Metabolite toxicology. [NA-Remove.]

8. Endocrine disruption. [There is no available evidence demonstrating that 

2-Pyrrolidinone, 1-butyl- is an endocrine disruptor in humans.]

C. Aggregate Exposure

1. Dietary exposure. [In examining aggregate exposure, section 408 of the 

Federal Food, Drug, and Cosmetic Act (FFDCA) directs EPA to consider available 

information concerning exposures from the pesticide residue in food and all other 

nonoccupational exposures, including drinking water from ground water or surface 

water and exposure through pesticide use in gardens, lawns, or buildings 

(residential and other indoor uses).

It is anticipated that 2-Pyrrolidinone, 1-butyl- will be used as a solvent/co-solvent in 

pesticide formulations at a concentration no higher than 75% with a potential enduse pesticide rate up to 4 pints/acre. 2-Pyrrolidinone, 1-butyl- is not expected to be 

persistent in the environment. Further, 2-Pyrrolidinone, 1-butyl- has a low toxicity 

profile as demonstrated through acute, subchronic, reproductive, developmental, 

and mutagenicity testing, and evaluation of its carcinogenicity potential. Therefore, 

dietary exposure to 2-Pyrrolidinone, 1-butyl- should not be of concern. 

2-Pyrrolidinone, 1-butyl- is not intended for direction application to water. 

Agricultural practices minimize spray drift and typical end-use product labels 

prohibit direct application to water. 2-Pyrrolidinone, 1-butyl- is ultimately 

biodegradable and is not expected to be persistent in the environment. Therefore, 
13

use of 2-Pyrrolidinone, 1-butyl- as a solvent/co-solvent in pesticide formulations 

does not pose a risk to drinking water.

Overall, 2-Pyrrolidinone, 1-butyl- is considered to be a low toxicity substance with a 

reasonable certainty of no harm from dietary exposure and all other 

nonoccupational sources of exposure.]

i. Food. [NA-Remove.]

ii. Drinking water. [NA-Remove.]

2. Non-dietary exposure. [NA-Remove.]

D. Cumulative Effects

[Section 408(b)(2)(D)(v) of the FFDCA requires that, when considering 

whether to establish, modify, or revoke a tolerance, the Agency consider available 

information concerning the cumulative effects of the particular pesticide’s residues 

and other substances that have a common mechanism of toxicity.

Taminco has not found 2-Pyrrolidinone, 1-butyl- to share a common mechanism of 

toxicity with any other substances, and 2-Pyrrolidinone, 1-butyl- does not appear to 

produce a toxic metabolite produced by other substances. 

Resultant risks, separately and/or combined with other substances that may have a 

common mechanism of toxicity, should be low for 2-Pyrrolidinone, 1-butyl-. 

Taminco does not expect any adverse cumulative effects associated with the use of 2-

Pyrrolidinone, 1-butyl-.]

E. Safety Determination

1. U.S. population. [2-Pyrrolidinone, 1-butyl- exhibits a low toxicity profile, 

as demonstrated by the acute, mutagenicity, subchronic, reproductive, and 

developmental studies summarized above, as well as the evaluation of its 

carcinogenetic potential.

When 2-Pyrrolidinone, 1-butyl- is used on raw agricultural commodities in 

accordance with good agricultural practice, it is expected to meet EPA’s reasonable 

certainty of no harm requirement. Based on the low toxicity profile of 2-

Pyrrolidinone, 1-butyl-, there is no reason to believe that adverse effects on the U.S. 

population will result from the use of this inert ingredient in pesticide formulations. 

In addition, there is no information or data to suggest that infants and children will 

be disproportionately at risk to the use of 2-Pyrrolidinone, 1-butyl- in pesticide 

formulations.]

2. Infants and children. [NA-Remove.]
14

F. International Tolerances

[There are no known U.S. or international tolerances or tolerance 

exemptions for 2-Pyrrolidinone, 1-butyl-. 

The similar substance, n-methylpyrrolidone (NMP), is exempt from the requirement 

of a tolerance under 40 CFR 180.920 when used as solvent or cosolvent in pesticide 

formulations.]