[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
