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EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

EPA Registration Division contact: William Cutchin 703-305-7990

Jeneil Biosurfactant Company

IN-10848

EPA has received a pesticide petition (IN-10848) from Jeneil Biosurfactant 

Company, 400 N. Dekora Woods Blvd. Saukville, WI 53080 requesting, 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 to establish an exemption from the requirement of a 

tolerance for methyl isobutyrate (CAS No.547-63-7) when used as an inert solvent 

applied to growing crops or harvested crops under 40 CFR 180.910 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. NA

2. Analytical method. NA

3. Magnitude of residues. NA

B. Toxicological Profile

There was little in the toxicity database of methyl isobutyrate. Structurally similar 

compounds were employed as read-across substances, including isobutyl isobutyrate, 

which was categorized by the Joint FAO/WHO Expert Committee on Food Additives 

(JECFA) into the same category as methyl isobutyrate, esters of aliphatic acyclic primary 

alcohols with branched chain aliphatic acyclic acids. Compounds in this category are 

natural components of a wide variety of foods and are metabolized by the 

carboxylesterases that hydrolyze them to component alcohols and carboxylic acids in the 

intestines, blood, and liver. In the case of methyl isobutyrate, the alcohol metabolite is 

methanol and for isobutyl isobutyrate, it is isobutanol. The acid metabolite in both cases 

is isobutyric acid.
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JECFA carried out a structural assessment of methyl isobutyrate toxicity using the 

method of Cramer, a peer-reviewed approach to classifying chemicals with respect to 

non-cancer risk from oral exposure. It primarily uses information on the toxicity of a 

chemical's substructures and the predicted pathway of mammalian metabolism. Other 

factors in the classification include whether the compound occurs naturally in the body 

and in food. The Expert Committee reviewed methyl isobutyrate as a member of the 

group esters of aliphatic acyclic primary alcohols with branched chain aliphatic acyclic 

acids, and determined that methyl isobutyrate and the other 31 compounds in this group 

belong in Cramer Structural Class I, the class of lowest concern, based on the absence of 

substructures associated with toxicity, an efficient metabolic pathway, and the fact that it 

is an endogenous chemical in food.

1. Acute toxicity. An LD50 value of 16,000 mg/kg/bw was determined in rats for 

methyl isobutyrate. The LC50 of methyl isobutyrate was reported to be 25.5 mg/L in 

mice. These correspond to acute toxicity category of IV for oral and inhalation routes of 

exposure. No further information was available on this compound's acute toxicity. The 

structurally similar compound isobutyl isobutyrate, which was also in the JECFA group 

esters of aliphatic acyclic primary alcohols with branched chain aliphatic acyclic acids, 

was Toxicity Category IV for dermal acute toxicity indicating low dermal toxicity 

potential.

2. Genotoxicty. Methyl isobutyrate did not significantly induce chromosome loss 

in mitotically growing Saccharomyces cerevisiae D61.M cells, without the presence of a 

known inducer. The structurally similar isobutyl isobutyrate did not induce reverse 

mutations in Salmonella typhimurium strains TA98, TAIOO, TA1535, and TA1537, or in 

Escherichia coli strain WP2 uvrA at concentrations as high as 5000 ug/mL in the absence 

or presence of metabolic activation.

An evaluation of the structure of methyl isobutyrate for alerts to genotoxicity 

yields no identifiable structures of concern. A "structural alert" is defined as a molecular 

substructure with a high correlation (>90% overall) to mutagenicity. The structural alert 

QSAR analysis is derived from data from 44 substructures and mutagenicity data from 

over 4000 chemicals from National Toxicology Program's (NTP) database and the 

Japanese Industrial Safety and Health Law (ISHL) database. None of the substructures 

are found in methyl isobutyrate, suggesting that is unlikely to be genotoxic.

3. Reproductive and developmental toxicity. In two prenatal developmental 

toxicity inhalation studies, mated female Wistar rats and Flimalayan rabbits were exposed 

to isobutanol (99.8%) at vapor concentrations of 0,151, 758 or 3030 ppm (0, 500, 2,500 

or 10,000 mg/m3

) for six hours/day. The rats were dosed on post-coitum days 6-15. No 

mortality or significant differences in clinical signs, body weight development, or gross 

pathology between controls and treated groups were observed. No effects on 

development were noted. The maternal and developmental rat NOAELs were 3030 ppm. 

Rabbits (15/dose) were dosed on postinsemination days 7-19. High-dose rabbit dams had 

a slightly lower body weight gain, particularly during the first phase of exposure. The 

maternal NOAEL for rabbits was 758 ppm. Fetuses exhibited no signs of developmental 
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changes in response to isobutanol. Therefore, the rabbit developmental NOAEL was 

3030 ppm, the highest dose.

In a 2-generation reproductive inhalation study isobutanol (99.9%) was 

administered to 30 Crl:CD(SD)IGS BR rats/sex/dose by whole body exposure at 0, 

500,1000 and 2500 ppm (0,1476, 2952, and 7380 mg/m^) for 6 hours per day 7 days per 

week. Exposure began at the commencement of the study for the F0 generation, and on 

postnatal day 28 for the F1 generation. It ended after weaning of the pups (F0 generation 

postnatal day 28, F1 generation postnatal day 21). For dams, exposure was discontinued 

after day 20 of gestation through lactation day 5. No exposure-related effects were 

observed on F0 and F1 parental survival or on F0 and F1 reproductive performance, body 

weights, food consumption and food efficiency in males or females. There were no 

significant spermatogenic or macroscopic findings, changes in primordial follicle or 

corpora lutea counts, changes in mean organ weights or histopathologic lesions in the F0

or F1 rats at any dose. Pup endpoints were not significant for either F1 or F2 generations, 

including survival, general physical condition, and mean body weights. There were no 

macroscopic findings, changes in mean organ weights, or maturation of F1 pups. The 

NOAEL of isobutanol for parental systemic, reproductive and neonatal toxicity is 2500 

ppm (7380 mg/m3 the maximum applied dose) in males and females of the F0, F1 and F2 

generations. The study was rated "reliable without restriction" by the European 

Chemicals Agency (ECHA).

4. Subchronic toxicity. No repeat-dose studies of methyl isobutyrate were 

identified in a search of the toxicological literature. Methyl isobutyrate was categorized 

by JECFA into the same category as isobutyl isobutyrate, for which a subchronic toxicity 

study exists. Isobutyl isobutyrate is similar in structure to methyl isobutyrate; both 

compounds contain an isobutyl ester group and are therefore expected to be similarly 

metabolized. 

In an 18-week oral gavage study Wistar rats (15/sex/dose) received doses of 0, 

10,100, or 1000 mg/kg bw/day. No lasting significant effects were noted in blood or urine 

parametes, histological examination, behavior, appearance, body weight, or food/water 

consumption. There were no significant changes in organ weights related to treatment of 

animals with isobutyl isobutyrate. The NOAEL was reported to be 1000 mg/kg/day.

The repeat-dose toxicity of isobutanol was also considered in the evaluation of 

methyl isobutyrate. Methyl isobutyrate and isobutanol have long been consumed by 

humans because both compounds are natural food chemicals as well as being food 

additives permitted for direct addition to food (21 CFR 172.515). This approach is further 

justified based on the structural similarity and metabolic relationship between the two 

compounds. Both have an oxy-isobutane group, plus both compounds are metabolized in 

vivo to form isobutyric acid in a 1:1 molar ratio. Based on these structural and metabolic 

similarities, it seems reasonable to conclude that isobutanol could also approximate the 

toxicity of methyl isobutyrate.

In a 90-day oral rodent toxicity study on isobutanol, which served as the scientific 

basis for US ERA's oral Reference Dose (RfD) for that compound, isobutanol was 
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administered to 30 Crj:CD(SD) rats/sex/dose by gavage for 90 days at dose levels of 

0,100, 316, or 1000 mg/kg bw/day. Treatment related effects were seen only at 1000 

mg/kg bw/day, and included hypoactivity, which was significant during week one and 

decreased markedly after week 4, and lower body weight gain (18% below that of control 

rats) in males during week one. Food consumption averages were below those of the 

controls for both males and females during weeks 1 and 2. Clinical signs and effects on 

body weight and food consumption were all transient and were considered as adaptive 

and therefore as not adverse. In addition, serum potassium levels were 11-15% lower in 

both sexes compared to controls on day 29, but group mean serum potassium

concentrations were similar for treated and control groups at the final clinical pathologic 

evaluation. No difference between dosed groups and controls were found for 

ophthalmoscopic examination, hematology, urinalysis, organ weights, gross pathology 

and histopathology. The NOEL determined to be 316 mg/kg bw/day and the NOAEL was 

1000 mg/kg/day. U.S. EPA derived an oral RfD of 0.3 mg/kg/day for isobutanol by 

applying uncertainty factors totaling 1000 to this NOEL.

Wistar rats (10/sex/group) were exposed to isobutanol in drinking water at 

concentrations of 0, 1000, 4000, or 16,000 ppm, equivalent to approximately 0, 80, 340, 

or 1450 mg/kg bw/day isobutanol actually ingested. The highest dose was chosen based 

on palatability. The 90-day study was carried out under OECD Test Guideline 408 and 

included full hematology, clinical chemistry, urinalysis, and ophthalmological endpoints 

as well as post-sacrifice histological exam. Body weight, food and water consumption, 

and clinical signs of toxicity were monitored throughout the study. The following organs 

were weighed: livers, kidneys, adrenal glands, and testes. There were no significant dosedependent signs of toxicity in any of these parameters. Study authors concluded that the 

NOAEL for isobutanol was the highest dose, 1450 mg/kg/day.

In a 90-day inhalation study, 99% pure isobutanol was administered by dynamic wholebody exposure to 10-20 Sprague-Dawley rats/sex/dose at 0, 250, 1000, or 2500 ppm for 6 

hours per day, 5 days/week. During exposure time only, there was a slight decreased 

response to external stimuli that disappeared immediately after exposure. ECHA 

considered it an effect of the narcotic properties of isobutanol rather than an adverse 

effect. In high dose females, total erythrocyte count, hemoglobin, and hematocrit were 

slightly elevated compared to controls (p < 0.05). ECHA considered this to be not 

biologically significant. No differences were found in body weight, food consumption, 

ophthalmoscopic examination, clinical observation, clinical chemistry, neurobehavioral 

observations, organ weights, gross pathology, and histopathology. The NOAEL for 

repeat-dose effects including neurotoxicity is 2500 ppm.

5. Chronic toxicity. There were no adequate studies on the carcinogenic potential 

of methyl isobutyrate or isobutanol. Methyl isobutyrate was not genotoxic in one study 

and it does not contain reactive substructures of concern.

6. Animal metabolism. Metabolism of aliphatic esters such as methyl isobutyrate

proceeds rapidly through hydrolysis to form an alcohol and carboxylic acid. These are 

reactions of the carboxylesterases or esterases, which predominate in hepatocytes but are 

present in most tissues throughout the body, including small intestine, colon, kidney, 
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trachea and lung. Hydrolysis of methyl isobutyrate is extensive and will form methanol 

and isobutyric acid. Isobutyric acid is metabolized to propionic acid which, in turn, is 

converted to succinic acid and ultimately to glucose and glycogen. Methanol is oxidized 

and excreted ultimately as CO2 and water.

7. Metabolite toxicology. NA

8. Endocrine disruption. Toxicity data related to endocrine disruption were not 

identified in the methyl isobutyrate database. As the scientific knowledge develops, 

screening of additional compounds may be added to the Endocrine Disruptor Screening 

Program (EDSP). When additional screening and/or testing is conducted, methyl 

isobutyrate may be the focus of screening and/or testing to better characterize effects 

related to endocrine disruption.

C. Aggregate Exposure

1. Dietary exposure. The estimated dietary exposure to methyl isobutyrate was

determined using methods to estimate chronic dietary exposure for a generic inert 

ingredient. This assessment considers drinking water and crop-specific residues from preharvest applications of agricultural insecticides, herbicides and fungicides, assuming the 

highest established tolerance level residue for each commodity. The assessment assumes 

that the ingredient is used on all crops. The inert ingredient is assumed to be present in all 

commodities treated with 57 of the most significant active ingredients at the maximum 

tolerance level as identified by the U.S. EPA for the default assessment. Chronic dietary 

exposure estimates were derived for the general US population and sub-groups of the 

population using the Dietary Exposure Evaluation Model, DEEMTM. The inert ingredient 

is assumed to be in the formulation at a concentration of 50% for the default assessment. 

Chronic dietary exposure estimates were derived for the general US population and 

subgroups of the population. The estimated exposure for the total US population is 

0.1893 mg/kg bw/day, or 1.89% of the cPAD. Children age 1 to 2 years old have the 

highest estimated exposure at 0.7062 mg/kg bw/day, or 7.06% of the cPAD.

i. Food. Dietary exposures of concern are not anticipated for methyl isobutyrate 

due to its lack of persistence in the environment and low general toxicity. A significant 

source of dietary methyl isobutyrate comes from natural food sources and its use as a 

food additive. Methyl isobutyrate occurs naturally in a wide variety of foods, including 

apple juice, bananas, blueberry, dill herb, grape, kiwi fruit, kumquat peel oil, melon, 

naranjilla fruit, papaya, pineapple, potato fried potato, starfruit, and strawberry juice. 

JECFA (1999) estimated the current level of intake of methyl isobutyrate as a flavoring 

agent to be 270 ug/day in the U.S., equivalent to approximately 0.00386 mg/kg bw/day 

for a 70-kg person.

ii. Drinking water. Methyl isobutyrate exposure via drinking water from use as an 

inert ingredient is not expected to be significant. The physical and chemical properties of 

methyl isobutyrate indicate it is moderately volatile, readily biodegradable, and therefore 

not persistent in water. Exposure via the drinking water was estimated in the DEEM 

dietary exposure assessment assuming a concentration of 100 ppb.
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2. Non-dietary exposure. Residential exposures of concern are not anticipated for

methyl isobutyrate due to its inherent ability to biodegrade in the environment, low 

projected use-level in pesticides, and low general toxicity.

D. Cumulative Effects

Section 408(b)(2)(D) (9v) 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 a particular pesticide's residues and "other 

substances that have a common mechanism of toxicity."

To our knowledge there are no available data or other reliable information that 

suggests any toxic effects produced by methyl isobutyrate would be cumulative with 

those of any other chemical compounds. EPA has not made a common mechanism of 

toxicity finding as to methyl isobutyrate and other compounds. Isobutyl isobutyrate does 

not produce toxic metabolites in common with other substances of potential concern. For 

the purpose of the tolerance exemption proposed, it is assumed that methyl isobutyrate 

does not share a common mechanism of toxicity with other substances.

E. Safety Determination

1. U.S. population. Taking into consideration all available information on methyl 

isobutyrate, there is a reasonable certainty that no harm to any population subgroup will 

result from dietary and other non-occupational exposures to methyl isobutyrate when 

used as an inert ingredient in an inert mixture intended for use in pesticide formulations. 

The toxicity profile of methyl isobutyrate indicates a low hazard from all routes of 

exposure, and a lack of genotoxicity. The NOAEL of 1000 mg/kg/day derived for 

isobutyl isobutyrate was used as a point of departure for methyl isobutyrate. Uncertainty 

factors often each for intra- and interspecies extrapolations were used, totaling l00x. An 

RfD was then established for methyl isobutyrate of 10 mg/kg/day. The chronic

Population Adjusted Dose (cPAD) was determined to be the same as the RfD because no 

effects of isobutanol on development or reproduction were observed and therefore there 

was insufficient evidence for increased susceptibility of sensitive populations. Therefore,

the oral RfD and cPAD for methyl isobutyrate are both 10 mg/kg/day. For the total US

population, the estimated chronic dietary exposure from food and drinking water for 

methyl isobutyrate, calculated as 50% of all agricultural formulations, is 1.89% of the 

cPAD. This estimated exposure to methyl isobutyrate is well below any level of potential 

concern.

2. Infants and children. There is a reasonable certainty that no harm to infants and

children will result from the use of methyl isobutyrate as an inert ingredient in pesticide

products. There is no indication that this chemical is a developmental toxin or that there 

is a concern for increased sensitivity to infants and children to methyl isobutyrate when 

used as an inert ingredient in pesticide formulations. For this reason, a safety factor 
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analysis has not been implemented to assess risk and the additional tenfold safety factor 

for the protection of infants and children is also unnecessary.

F. International Tolerances

NA