UNITED STATES ENVIRONMENT AL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

MEMORANDUM 

DATE: June 4, 2015 

SUBJECT: 1-Naphthaleneacetic acid (NAA): Response to Comments on the HED Human 

Health Scoping Document. 

PC Code: 056001 , 056002, 056003, 056004, 056007, DP Barcode: 0427651 

056008 

Decision No.: 505619 Registration No.: NA 

Petition No.: NA Regulatory Action: Registration Review 

Risk Assessment Type: Single Chemical Aggregate Case No.: 0379 

TXRNo.: NA CAS No.: 86-87-3 (NAA) 

MRID No.: NA 40 CFR: § 180. 155 

FROM: Thurston Morton, Senior Chemist ~ ((( 

Abdallah Khasawinah, PhD., Toxicologist · ('"~ 

Ivan Nieves, Chemist 

Risk Assessment Branch IV 

Health Effects Division (7509P) 

THROUGH: Charles Smith, Branch Chie ....___ __ ---., 

Risk Assessment Branch IV ----

Health Effects Division (7509P) 

TO: Lata Venkateshwara, Chemical Review Manager (RM 53) 

Risk Management and Implementation Branch III 

Pesticide Re-Evaluation Division (7508P) 

-

Attached is HED's Response to Comment on the human health risk assessment scoping 

document for NAA to support Registration Review. 

The HED NAA Risk Assessment team has received comments on the Registration Review 

Scoping Document (EPA Docket ID: EPA-HQ-OPP-2014-0773-0009). Comments relevant to 

HED's scoping document were provided by the Physicians Committee for Responsible Medicine 

AMVAC. 

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EPA'S RESPONSE TO COMMENTS FOR NAA 

I. Introduction 

The following is EPA's response to public comments on the human-health assessment scoping 

document in support of Registration Review for NAA. Some of the responses serve as 

clarification or a restatement of Agency policies and guidance and it is hoped that this will 

provide a greater understanding of the Agency's position and procedures on these matters. 

Comments concerning the rationale behind Agency decisions, toxicology, exposure assessment, 

and interpretation of available data, were submitted. 

II. Comments 

870.3-165 Subchronic inhalation study 

AMV AC Comment: 

AMY AC is willing to accept the additional 1 OX safety factor for this study guideline data base 

om1ss1on. 

HED Response: 

The Agency acknowledges the acceptance of the additional IOX for the lack of the subchronic 

inhalation study. If in the future, the inhalation MO Es are of concern the inhalation study may 

be required. 

Physicians Committee for Responsible Medicine Comment: 

With respect to the subchronic inhalation data requirement (870.3465), we found the following 

data which may fulfill the Agency's needs without additional testing, or in a read-across 

assessment. 

" CAS Number 86-87-3: > 0.45 mg/I (1-NAA, whole body, rat) 

0 CAS Number 61-31-4: > 5.0 mg/l (1-NAA-Na, nose-only, rat) 

11 CAS Number 86-86-2: > 2. 17 mg/I (whole body, rat) 1 

1 European Food Safety Authority; Conclusion on the peer review of the pesticide risk assessment of the active 

substance 1-naphthylacetic acid. EFSA Journal 2011 ;9(2):2019. Web accessed on February 11 , 2015 at: 

http://www.efsa.europa.eu/en/efsajoumal/doc/20 19.pdf. 

HED Response: 

The referenced material are acute inhalation LCso values and do not satisfy the requirement for a 

subchronic inhalation study. The subchronic inhalation study is required. However, in another 

comment from AMY AC they accept the additional I OX safety factor for this study guideline data 

base omission. 

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860.1380 Storage stability data (processed commodities of apples or citrus and olives) All six 

NAA compounds 

AMV AC Comment: 

AMV AC is committing to conduct this study. Because of chemistry considerations, AMY AC 

intends to demonstrate that NAA and its salts have a high level of chemical stability at ca. -20° 

for a I -year period. On this basis, the study design will entail fortification of the processed 

matrices at ca. 1 ppm using an equal-molar amount ofNAA and its salts. The acetamide and 

ethyl ester will be conducted separately. Because of the high water solubility ofNAA and its 

salts, there is no likelihood of residues in oils and AMY AC would propose not including stability 

testing of olive oil within the program. Otherwise, the commodities to be tested for all six NAA 

compounds would include apple wet pomace and apple juice. 

HED Response: 

The Agency looks forward to the submittal of the storage stability data. A waiver request must 

be submitted for the proposal for not conducting the olive oil storage stability data along with 

rationale. The Agency will review and utili ze them (if adequate), during the Registration Review 

ofNAA. 

860. 1520 Citrus Processing Study (dried pulp, oil andjuice) All six NAA compound'i 

AMV AC Comment: 

AMY AC intends to register only the potassium salt of naphthalene acetic acid (NAA) for use on 

citrus. For that reason, a processing study on citrus would only employ the use of this salt as the 

test substance. On this basis, AMY AC is committing to performing a citrus processing study for 

determining the potential for residue concentration in dried pulp, oil, and juice. We are also 

requesting waivers for the citrus processing studies for NAA, its sodium and ammonium salts, 

the ethyl ester, and the acetarnide. 

HED Response: 

The Agency looks forward to the submittal of the processing data for the potassium salt and 

waiver requests for NAA's sodium and ammonium salts, the ethyl ester, and the acetamide. The 

Agency will review and utilize them (if adequate), during the Registration Review ofNAA. 

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860. 1650 Analytical Reference Standards PAI, all six NAA compounds 

AMV AC Comment: 

AMV AC commits to fulfilling this requirement. 

HED Response: 

The Agency looks forward to the submission of the analytical standards. Please submit them to 

the following address: 

Analytical standards and all residues of concern must be submitted and replenished as requested 

by the EPA Pesticide Repository. 

The analytical reference standards must be sent to the Analytical Chemistry Lab, which is 

located at Fort Meade. Send them to the attention of either Theresa Cole or Thuy Ngygen at the 

following address: 

USEPA 

National Pesticide Standards Repository/ Analytical Chemistry Branch/OPP 

70 I Mapes Road 

Fort George G. Meade, MD 20755-5350 

The extended zip code must be used or the mail will be returned. 

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