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EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

EPA Registration Division contact: Laura Nollen, (703) 305-7390

Interregional Research Project Number 4 (IR-4)

Pesticide Petition Number 2E7991

EPA has received a pesticide petition, 2E7991, from Interregional Research 

Project Number 4 (IR-4), Rutgers, The State University of New Jersey, 500 College Road 

East, Suite 201 W, Princeton, NJ 08540 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 by establishing a tolerance for residues of 1-Naphthaleneacetic acid (NAA) and 

its conjugates in or on the raw agricultural commodities rambutan at 3 parts per million 

(ppm); avocado, mamey sapote and mango at 0.05 ppm; and fruit, pome, group 11-10 at 

0.15 ppm. Upon approval of the aforementioned tolerances, this petition additionally

requests to remove the tolerance for fruit, pome, group 11 at 0.15 ppm, as it will be 

superseded by the tolerance on fruit, pome, group 11-10 at 0.15 ppm.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. HED has now determined that the terminal residues of 

concern in plants are the parent compounds, NAA and its conjugates, based on the nature 

of residues identified from apple and olive studies [MRID 43948501 and 44190501].1

2. Analytical method. The nature of the residues of NAA is adequately understood 

and an acceptable analytical method is available for enforcement purposes.2

3. Magnitude of residues. . Avocados – All total NAA residues from five avocado 

field trials were <0.050 ppm at a 10 (+/-1) PHI after each application. All total NAA 

residues were also <0.050 ppm in the decline trial. Rambutan – The results from two 

rambutan trials show that the maximum total residue of NAA in rambutan fruit was 0.636 

ppm after one application of NAA (90 ppm solution applied to runoff) and a 2 day PHI.2

B. Toxicological Profile

1. Acute toxicity. NAA and all its conjugates show low acute toxicity.3
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2. Genotoxicty. NAA and all its conjugates are not mutagenic.3

3. Reproductive and developmental toxicity. There was no evidence of 

developmental toxicity at highest doses tested of 250 mg/kg/day in the rat or 150 

mg/kg/day of NAA in the rabbit administered by gavage during the critical gestation 

period of pregnancy. Reproductive effects of NAA sodium salt occurred at 210 

mg/kg/day and were limited to reduced litter survival and pup weight throughout 

lactation in both generations of offspring in a two generation reproduction study. Parental 

effects (reduced body weight gain and reduced food consumption) occurred at the same 

dose level.4

4. Subchronic toxicity The most common short term effect from high exposures to 

NAA and all its conjugates is reduced body weight gain, seen at dose levels of 200 

mg/kg/day and higher. 3

5. Chronic toxicity. Repeated exposure in the oral toxicity studies primarily 

resulted in decreased body weight and body weight gain accompanied by decreased food 

consumption. Other chronic effects included vomiting, stomach lesions and slight 

sinusoidal histiocytosis in the livers of males (dogs) .Studies in the rat and mouse have 

shown no evidence of carcinogenicity .4

6. Animal metabolism. The metabolism studies of the acid and its acetamide and 

the ethyl ester in animals provide supporting evidence that the toxicity of these various 

forms of NAA would be expected to be similar since all are metabolized to the acid form 

and eliminated from the body within 36 to 48 hours after exposure as glycine and 

glucuronic acid conjugates.4

7. Metabolite toxicology. EPA has not identified any metabolites of toxicological 

concern.3

8. Endocrine disruption. As the appropriate screening and/or testing protocols 

under the Agency’s EDSP have now been developed and vetted, the naphthalene acetates 

may be subjected to additional screening and/or testing to better characterize effects 

related to endocrine disruption.

C. Aggregate Exposure

1. Dietary exposure. The acute and chronic aggregate risk assessments for 

naphthalene acetates include exposure from food and drinking water only. Both acute 

and chronic aggregate risks are not of concern.3

i. Food. Based on analyses of estimated dietary risks for the general U.S. 

population and various population subgroups, the acute and chronic dietary exposure 

estimates for naphthalene acetates are significantly below EPA’s level of concern for all 

supported commodities and not a risk of concern.3
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ii. Drinking water. Based on screening level computer models that provide highend estimates of pesticide concentrations for surface and ground water sources, all 

EDWCs are low and do not pose risks of concern.3

2. Non-dietary exposure. Residential – Estimated dermal and inhalation MOEs for 

the most highly exposed scenario of residential exposure to the naphthalene acetates are 

well above the target MOE of 100 and do not pose risks of concern. Occupational 

Handler – The Agency believes all naphthalene acetate handler risks are not of concern 

and all handlers will only be required to wear baseline PPE. Post-Application Exposure –

The MOEs for the two post-application exposure scenarios are well above the target 

MOE of 100 on the day of application and, therefore, not of risk concern.3

D. Cumulative Effects

Unlike other pesticides for which EPA has followed a cumulative risk approach 

based on a common mechanism of toxicity, EPA has not made a common mechanism of 

toxicity finding for the naphthalene acetates. They do not appear to produce a toxic 

metabolite produced by other substances. Therefore, for the purpose of risk assessments, 

EPA has not assumed that the naphthalene acetates have a common mechanism of 

toxicity with other substances.3

E. Safety Determination Acute and chronic risk estimates for all commodities are less 

than 100% of the aPAD (0.5 mg/kg/day) and cPAD (0.15 mg/kg/day).2 The % aPAD and 

% cPAD utilized by the proposed tolerances are for small use minor crops and are not 

expected to add to the existing percentages.

1. U.S. population. 2% of the aPAD and 1% of the cPAD.3

2. Infants and children. Infants – 8% of the aPAD and 6% of the cPAD. 

Children – 10% of the aPAD and 8% of the cPAD.3

F. International Tolerances

No maximum residue limits (MRLs) for NAA, its salts, ester, and acetamide have 

been established in the Codex Alimentarius, the food code established by the UN’s World 

Health Organization and the Food and Agriculture Organization; therefore, issues of 

compatibility between Codex MRLs and U.S. tolerances do not exist. Moreover, no 

Canadian or Mexican MRLs have been established for naphthalene acetates.3

FOOTNOTES:

1. 1-Naphthaleneacetic Acid (NAA), its Salts, Ester, and Acetamide. Residue Chemistry Considerations 

for Reregistration Eligibility Decision. Case No. 0379.

2. Enclosed Petition Proposing Tolerances for NAA Use in Avocado, Mango, Mamey Sapote and 

Rambutan

3. Amended Reregistration Eligibility Decision. October 2007.
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4. 1-Naphthaleneacetic Acid – Toxicology Disciplinary Chapter for the Reassessment Eligibility Decision 

(RED) (or Registration Support) Document (Revised). March 8, 2004