[Federal Register Volume 59, Number 143 (Wednesday, July 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17774]


[[Page Unknown]]

[Federal Register: July 27, 1994]


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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180

[OPP-300296; FRL-4635-3]
RIN No. 2070-AC18

 

Acrylonitrile-Butadiene Copolymer; Tolerance Exemption

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to establish an exemption from the 
requirement of a tolerance for residues of acrylonitrile-butadiene 
copolymer(CAS Reg. No. 9003-18-3) when used as an inert ingredient 
(component of ear tags and similar slow-release devices) in pesticide 
formulations applied to animals. Y-Tex Corp. requested this regulation.
DATES: Comments, identified by the document control number, [OPP-
300296], must be received on or before August 26, 1994.

ADDRESSES: By mail, submit written comments to: Public Response and 
Program Resources Branch, Field Operations Division (7506C), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460. In person, bring comments to: Rm. 1132, CM #2, 
1921 Jefferson Davis Hwy., Arlington, VA 22202.
    Information submitted as a comment concerning this document may be 
claimed confidential by marking any part or all of that information as 
``Confidential Business Information'' (CBI). Information so marked will 
not be disclosed except in accordance with procedures set forth in 40 
CFR part 2. A copy of the comment that does not contain CBI must be 
submitted for inclusion in the public record. Information not marked 
confidential will be included in the public docket by EPA without prior 
notice. The public docket is available for inspection in Rm. 1132, at 
the address given above, from 8 a.m. to 4 p.m., Mondays through 
Fridays, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: By mail: Kerry B. Leifer, Registration 
Support Branch, Registration Division (7505W), Office of Pesticide 
Programs, Environmental Protection Agency, 401 M St., SW., Washington, 
DC 20460. Office location and telephone number: 2800 Crystal Drive, 
Arlington, VA 22202, (703)-308-8323.

SUPPLEMENTARY INFORMATION:

I. Background

    EPA issued a proposed rule in the Federal Register of February 3, 
1989 (54 FR 5502), in which it announced that the Y-Tex Corp., P.O. Box 
1450, 1825 Big Horn Ave., Cody, WY 82414, had requested that the 
Administrator amend 40 CFR 180.1001(e) by establishing an exemption 
from the requirement of a tolerance under section 408(e) of the Federal 
Food, Drug and Cosmetic Act (FFDCA) (21 U.S.C. 346a(e)) for 
acrylonitrile-butadiene copolymer, FD & C Yellow No. 6 aluminum lake, 
2-(2'-hydroxy-5'-methylphenyl)benzotriazole and octadecyl 3,5-di-tert-
butyl-4-hydroxyhydrocinnamate when used as components of ear tags and 
similar slow-release devices in pesticide formulations applied to 
animals.
    One comment was received in response to the proposed rule. The 
commenter claimed that among the bases for approval of the 
acrylonitrile-butadiene copolymer is an erroneous interpretation of the 
results of a risk assessment conducted by the U. S. Food and Drug 
Administration (FDA).
    One of the bases for approval listed in the proposed rule under the 
subheading ``acrylonitrile-butadiene copolymer'' references an FDA risk 
assessment for acrylonitrile monomer and states, ``. . . the worst case 
exposure to this monomer would result in an upper daily lifetime 
oncogenic risk of less than 1.2 X 10-7, based upon a daily 
lifetime consumption of 1,060 grams of soft drinks contained in 
acrylonitrile/styrene plastic beverage bottles (from which the monomer 
might be expected to migrate) with acrylonitrile monomer concentration 
not exceeding 80 ppm.'' The quoted language (49 FR 36635; September 19, 
1984) was part of the preamble of a Federal Register document that 
amended the food additive regulations at 21 CFR 177.1040(c) to add a 
description of an acrylonitrile/styrene copolymer suitable for use in 
packaging soft drinks.
    The commenter noted that the maximum residual acrylonitrile monomer 
content of a finished article intended for such use is specified in the 
regulation as 0.10 ppm rather than 80 ppm. The FDA assessment of risk 
used as a basis of approval was based upon the 0.10-ppm value. In 
addition, the commenter asserted that the barrier properties of the 
acrylonitrile/styrene copolymer that is the subject of 21 CFR 177.1040 
are such that the migration of the residual acrylonitrile monomer would 
occur more slowly and to a lesser extent than would be the case for the 
acrylonitrile-butadiene copolymer for which the exemption from the 
requirement of a tolerance was proposed. For the reasons cited above, 
the commenter claimed that EPA's citation of the FDA calculation of the 
lifetime risk from exposure to monomeric acrylonitrile does not support 
the action proposed.
    EPA agrees with the comment and in response EPA has decided to 
reissue a proposal to establish an exemption from the requirement of a 
tolerance for the acrylonitrile-butadiene copolymer that includes a 
revised calculation of lifetime risk from exposure to monomeric 
acrylonitrile.

II. Application of Assessment in Proposed Rulemaking

A. Exposure to Acrylonitrile Monomer

    Data provided by the petitioner regarding the levels of 
acrylonitrile monomer typically expected to be present in the subject 
acrylonitrile-butadiene copolymer indicate that the concentration does 
not exceed 1 part per million (ppm). Using this concentration of 
acrylonitrile monomer and the conditions of use of the acrylonitrile-
butadiene copolymer in animal ear tags, an estimation of exposure to 
acrylonitrile monomer resulting from the use of acrylonitrile-butadiene 
copolymer as a component of an animal tag or similar devices was 
conducted.
    The following assumptions were incorporated into a ``worst-case'' 
exposure assessment:
    1. The subject acrylonitrile-butadiene copolymer contains a 
residual acrylonitrile monomer concentration of 1 ppm.
    2. The copolymer comprises 50% of the weight of the tag.
    3. The tag weight does not exceed 15 grams.
    4. Each animal wears two tags.
    5. The animal weighs 800 pounds (363.2 kilograms). This would 
correspond to the lower range of weight for beef cattle, the 
predominant wearers of insecticidal animal tags.
    6. All acrylonitrile monomer present in the tags migrates into the 
animal and is not metabolized and/or excreted.
    7. A human diet of 3,000 grams per day consists solely of meat 
emanating from cattle wearing tags containing acrylonitrile monomer.
These ``worst-case'' assumptions produce an estimate of human 
acrylonitrile monomer dietary consumption of 0.12 microgram per day.

B. Toxicity of Acrylonitrile Monomer

    As described in the previously cited Federal Register document 
establishing a food-additive regulation for acrylonitrile-styrene 
copolymer, the FDA's Center for Food Safety and Applied Nutrition 
Cancer Assessment Committee concluded from its quantitative risk 
assessment that acrylonitrile monomer exposure corresponding to an 
upper-limit lifetime risk of 10-6, i.e., 1 in 1 million, is about 
0.5 to 1.0 microgram per day.

C. Extrapolation of Risk for Acrylonitrile Monomer

    Using the above FDA quantitative risk assessment and the ``worst-
case'' exposure estimate, EPA concludes that the upper-limit individual 
lifetime risk for acrylonitrile monomer resulting from the use of 
acrylonitrile-butadiene copolymer as a component of an animal ear tag 
is about 1.2 X 10-7 to 2.4 X 10-7, or slightly more than 1 in 
7 million.
    Because of the numerous conservative assumptions included in the 
worst-case exposure estimate, lifetime-averaged individual exposure to 
acrylonitrile monomer is expected to be significantly less than the 
estimated exposure and, therefore, the calculated upper-bound risk 
would be significantly less.

III. Additional Bases of Approval

    In the case of certain chemical substances which are defined as 
``polymers,'' the Agency has established a set of criteria which 
identify categories of polymers that present low risk. These criteria 
(described in 40 CFR 723.250) identify polymers that are relatively 
unreactive and stable compared to other chemical substances as well as 
polymers that typically are not readily absorbed. These properties 
generally limit a polymer's ability to cause adverse effects. In 
addition, these criteria exlcude polymers about which little is known. 
The Agency believes that polymers meeting the criteria noted above will 
present minimal or no risk. Acrylonitrile-butadiene copolymer conforms 
to the definition of a polymer given in 40 CFR 723.250(b)(11) and meets 
the following criteria which are used to identify low-risk polymers.
    1. The minimum number average molecular weight of acrylonitrile-
butadiene copolymer is greater than 1,000. Substances with molecular 
weights greater than 400 are generally not readily absorbed through the 
intact skin, and substances with molecular weights greater than 1,000 
are generally not absorbed through the intact gastrointestinal (GI) 
tract. Chemicals not absorbed through the skin or GI tract are 
generally incapable of eliciting a toxic response.
    2. Acrylonitrile-butadiene copolymer is not a cationic polymer nor 
is it reasonably expected to become a cationic polymer in a natural 
aquatic environment.
    3. Acrylonitrile-butadiene copolymer does not contain less than 
32.0 percent by weight of the atomic element carbon.
    4. Acrylonitrile-butadiene copolymer contains as an integral part 
of its composition the atomic elements carbon, hydrogen, nitrogen, and 
oxygen.
    5. Acrylonitrile-butadiene copolymer does not contain as an 
integral part of its composition, except as impurities, any elements 
other than those listed in 40 CFR 723.250(d)(3)(ii).
    6. Acrylonitrile-butadiene copolymer is not a biopolymer, a 
synthetic equivalent of a biopolymer, or a derivative or modification 
of a biopolymer that is substantially intact.
    7. Acrylonitrile-butadiene copolymer is not manufactured from 
reactants containing, other than as impurities, halogen atoms or cyano 
groups.
    8. Acrylonitrile-butadiene copolymer does not contain reactive 
functional groups that are intended or reasonably anticipated to 
undergo further reaction.
    9. Acrylonitrile-butadiene copolymer is not designed or reasonably 
anticipated to substantially degrade, decompose, or depolymerize.
    Based upon the information above and review of its use, EPA has 
found that, when used in accordance with good agricultural practice, 
this ingredient is useful and that the establishment of a tolerance is 
not necessary to protect the public health. Therefore, EPA proposes 
that the exemption from the requirement of a tolerance be established 
as set forth below.
    Any person who has registered or submitted an application for 
registration of a pesticide, under the Federal Insecticide, Fungicide, 
and Rodenticide Act (FIFRA), as amended, which contains the ingredient 
listed herein, may request, within 30 days after publication of this 
document in the Federal Register, that this rulemaking proposal be 
referred to an Advisory Committee in accordance with section 408(e) of 
FFDCA.
    Interested persons are invited to submit written comments on the 
proposed regulation. Comments must bear a notation indicating the 
document control number, [OPP-300296]. All written comments filed in 
response to this petition will be available in the Public Response and 
Program Resources Branch, at the address given above from 8 a.m. to 4 
p.m., Monday through Friday, except legal holidays.
    The Office of Management and Budget has exempted this rule from the 
requirements of section 2 of Executive Order 12866.
    Pursuant to the requirements of the Regulatory Flexibility Act 
(Pub. L. 96-354, 94 Stat. 1164, 5 U.S.C. 601-612), the Administrator 
has determined that regulations establishing new tolerances or raising 
tolerance levels or establishing exemptions from tolerance requirements 
do not have a significant economic impact on a substantial number of 
small entities. A certification statement to this effect was published 
in the Federal Register of May 4, 1981 (46 FR 24950).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.

Dated: June 29, 1994.

Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.

    Therefore, it is proposed that 40 CFR part 180 be amended as 
follows:

PART 180--[AMENDED]

    1. The authority citation for part 180 continues to read as 
follows:

    Authority: 21 U.S.C. 346a and 371.

    2. In Sec. 180.1001, by amending paragraph (e) in the table therein 
by adding and alphabetically inserting the inert ingredient, to read as 
follows:


Sec. 180.1001   Exemptions from the requirement of a tolerance.

* * * * *
    (e) * * *

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    Inert ingredients            Limits                   Uses          
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                              * * * * * * *                             
Acrylonitrile-butadiene    ..................  Carrier in animal tag and
 copolymer (CAS Reg. No.                        similar slow-release    
 9003-18-3) conforming to                       devices.                
 21 CFR 180.22, minimum                                                 
 average molecular weight                                               
 1,000..                                                                
                                                                        
                              * * * * * * *                             
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[FR Doc. 94-17774 Filed 7-26-94; 8:45 am]
BILLING CODE 6560-50-F