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Isobutane; Exemption From the Requirement of a Tolerance

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Information about this document as published in the Federal Register.

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AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Final rule.

SUMMARY:

This regulation establishes an exemption from the requirement of a tolerance for residues of isobutane (CAS Reg. No. 75-28-5) when used as an inert ingredient (propellant) in pesticide formulations applied to growing crops and raw agricultural commodities after harvest, and when used as an inert ingredient (propellant) in pesticide formulations applied to animals (used for food). Landis International, on behalf of Whitmire Micro-Gen, submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting establishment of an exemption from the requirement of a tolerance. This regulation eliminates the need to establish a maximum permissible level for residues of isobutane.

DATES:

This regulation is effective February 2, 2011. Objections and requests for hearings must be received on or before April 4, 2011 and must be filed in accordance with the instructions provided in 40 CFR part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES:

EPA has established a docket for this action under docket identification (ID) number EPA-HQ-OPP-2009-0676. All documents in the docket are listed in the docket index available at http://www.regulations.gov. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available in the electronic docket at http://www.regulations.gov, or, if only available in hard copy, at the OPP Regulatory Public Docket in Rm. S-4400, One Potomac Yard (South Bldg.), 2777 S. Crystal Dr., Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The Docket Facility telephone number is (703) 305-5805.

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FOR FURTHER INFORMATION CONTACT:

Elizabeth Fertich, Registration Division (7505P), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (703) 347-8560; e-mail address: fertich.elizabeth@epa.gov.

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SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. Potentially affected entities may include, but are not limited to:

  • Crop production (NAICS code 111).
  • Animal production (NAICS code 112).
  • Food manufacturing (NAICS code 311).
  • Pesticide manufacturing (NAICS code 32532).

This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. If you have any questions regarding the applicability of this action to a particular entity, consult the person listed under FOR FURTHER INFORMATION CONTACT.

B. How can I get electronic access to other related information?

You may access a frequently updated electronic version of 40 CFR part 180 through the Government Printing Office's e-CFR site at http://www.gpoaccess.gov/​ecfr. To access the harmonized test guidelines referenced in this document electronically, please go to http://www.epa.gov/​ocspp and select “Test Methods and Guidelines.”

C. How can I file an objection or hearing request?

Under FFDCA section 408(g), 21 U.S.C. 346a, any person may file an objection to any aspect of this regulation and may also request a hearing on those objections. You must file your objection or request a hearing on this regulation in accordance with the instructions provided in 40 CFR part 178. To ensure proper receipt by EPA, you must identify docket ID number EPA-HQ-OPP-2009-0676 in the subject line on the first page of your submission. All objections and requests for a hearing must be in writing, and must be received by the Hearing Clerk on or before April 4, 2011. Addresses for mail and hand delivery of objections and hearing requests are provided in 40 CFR 178.25(b).

In addition to filing an objection or hearing request with the Hearing Clerk as described in 40 CFR part 178, please submit a copy of the filing that does not contain any CBI for inclusion in the public docket. Information not marked confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA without prior notice. Submit a copy of your non-CBI objection or hearing request, identified by docket ID number EPA-HQ-OPP-2009-0676, by one of the following methods:

  • Federal eRulemaking Portal: http://www.regulations.gov. Follow the on-line instructions for submitting comments.
  • Mail: Office of Pesticide Programs (OPP) Regulatory Public Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001.
  • Delivery: OPP Regulatory Public Docket (7502P), Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South Bldg.), 2777 S. Crystal Dr., Arlington, VA. Deliveries are only accepted during the Docket Facility's normal hours of operation (8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays). Special arrangements should be made for deliveries of boxed information. The Docket Facility telephone number is (703) 305-5805.

II. Petition for Exemption

In the Federal Register of October 7, 2009 (74 FR 51597) (FRL-8792-7), EPA issued a notice pursuant to section 408 of FFDCA, 21 U.S.C. 346a, announcing the filing of a pesticide petition (PP 9E7586) by Whitmire Micro-Gen, c/o Landis International, P.O. Box 5126, Valdosta, GA 31603-5126. The petition requested that 40 CFR 180.910 and 40 CFR 180.930 be amended by establishing an exemption from the requirement of a tolerance for residues of isobutane (CAS Reg. No. 75-28-5) when used as an inert ingredient (propellant) in pesticide formulations applied pre- and post-harvest and pesticide formulations applied to animals. That notice referenced a summary of the petition prepared by Start Printed Page 5688Landis International, on behalf of Whitmire Micro-Gen, the petitioner, which is available in the docket, http://www.regulations.gov. There were no comments received in response to the notice of filing.

III. Inert Ingredient Definition

Inert ingredients are all ingredients that are not active ingredients as defined in 40 CFR 153.125 and include, but are not limited to, the following types of ingredients (except when they have a pesticidal efficacy of their own): Solvents such as alcohols and hydrocarbons; surfactants such as polyoxyethylene polymers and fatty acids; carriers such as clay and diatomaceous earth; thickeners such as carrageenan and modified cellulose; wetting, spreading, and dispersing agents; propellants in aerosol dispensers; microencapsulating agents; and emulsifiers. The term “inert” is not intended to imply nontoxicity; the ingredient may or may not be chemically active. Generally, EPA has exempted inert ingredients from the requirement of a tolerance based on the low toxicity of the individual inert ingredients.

IV. Aggregate Risk Assessment and Determination of Safety

Section 408(c)(2)(A)(i) of FFDCA allows EPA to establish an exemption from the requirement for a tolerance (the legal limit for a pesticide chemical residue in or on a food) only if EPA determines that the tolerance is “safe.” Section 408(b)(2)(A)(ii) of FFDCA defines “safe” to mean that “there is a reasonable certainty that no harm will result from aggregate exposure to the pesticide chemical residue, including all anticipated dietary exposures and all other exposures for which there is reliable information.” This includes exposure through drinking water and in residential settings, but does not include occupational exposure. Section 408(b)(2)(C) of FFDCA requires EPA to give special consideration to exposure of infants and children to the pesticide chemical residue in establishing a tolerance and to “ensure that there is a reasonable certainty that no harm will result to infants and children from aggregate exposure to the pesticide chemical residue.* * *”

EPA establishes exemptions from the requirement of a tolerance only in those cases where it can be clearly demonstrated that the risks from aggregate exposure to pesticide chemical residues under reasonably foreseeable circumstances will pose no appreciable risks to human health. In order to determine the risks from aggregate exposure to pesticide inert ingredients, the Agency considers the toxicity of the inert in conjunction with possible exposure to residues of the inert ingredient through food, drinking water, and through other exposures that occur as a result of pesticide use in residential settings. If EPA is able to determine that a finite tolerance is not necessary to ensure that there is a reasonable certainty that no harm will result from aggregate exposure to the inert ingredient, an exemption from the requirement of a tolerance may be established.

Consistent with section 408(c)(2)(A) of FFDCA, and the factors specified in FFDCA section 408(c)(2)(B), EPA has reviewed the available scientific data and other relevant information in support of this action. EPA has sufficient data to assess the hazards of and to make a determination on aggregate exposure for isobutane including exposure resulting from the exemption established by this action. EPA's assessment of exposures and risks associated with isobutane follows.

A. Toxicological Profile

EPA has evaluated the available toxicity data and considered their validity, completeness, and reliability as well as the relationship of the results of the studies to human risk. EPA has also considered available information concerning the variability of the sensitivities of major identifiable subgroups of consumers, including infants and children.

Isobutane is an asphyxiant and acute exposure may cause tachypnea and tachycardia. While direct contact with the liquid may cause burns, the vapor has no effects on the skin and eyes. Sudden death has also been reported from abusive “sniffing” of products containing isobutane, especially lighter refills. In a safety assessment of isobutane as a cosmetic ingredient (1982), dermal irritation in humans was very slight and transient erythema occurred randomly. Repeated inhalation exposure did not result in any changes in electroencephalograms, adrenocortical function, pulmonary function, neurological response, subjective response, cardiac function or cognitive response.

Acute toxicity data on isobutane were limited to inhalation exposure and eye and skin irritation. Isobutane was not acutely toxic via the inhalation route and was basically non-irritating to the skin and eyes of rabbits.

Several studies were found in which monkeys, rabbits, and rats were exposed to formulations or to mixtures containing isobutane. No toxicity was reported for two species of monkeys and one species of rabbit exposed for 90 days to various formulations containing isobutane.

No effects on survival, body weight, hematology, clinical pathology, or liver and kidney weights were observed in rats exposed to 0, 1,000, or 4,500 ppm (equivalent to 0, 622 or 2,803 milligrams/kilogram/day (mg/kg/day) of a 50:50 mixture of isobutane: isopentane for 13 weeks, however clinical signs included hunched posture, lethargy and crusted eyes in both exposure groups. There were no clinical signs of toxicity observed and no gross or microscopic lesions seen in Sprague-Dawley rats exposed to 0, 44, 432, or 4,437 ppm (equivalent to 0, 27, 269, or 2,763 mg/kg/day) of a mixture containing 25% each of n-butane, isobutane, n-pentane, and isopentane for 3 weeks.

In a 4-week sub-chronic toxicity study combined with reproduction/developmental toxicity screening and neurotoxicity screening study, Sprague Dawley CD rats were treated with isobutane (purity 99.0%) to assess the repeated dose, reproductive and developmental toxicity potential of this material when administered by whole body inhalation exposure. A no-observed-adverse effect level (NOAEL) of 9,000 ppm (equivalent to 5,600 mg/kg/day) was concluded for general systemic/neurotoxic (parental) endpoints in this study. Based on decreased male and female fertility and increased post-implantation loss in the 9,000 ppm group, the fertility and reproductive endpoints NOAEL was determined to be 3,000 ppm (equivalent to 1,867 mg/kg/day). There were no effects on offspring survival, body weight and development up to post-natal day 4. A NOAEL of 9,000 ppm (equivalent to 5,600 mg/kg/day) was concluded for developmental effects. No effects on functional observational battery parameters and motor activity were observed in this study.

In terms of neurotoxicity, acute toxicity studies show effects on the central nervous system (CNS) with rodents more sensitive than dogs. Exposure to a concentration of 55% was lethal in dogs, while 41-52% was lethal to mice within 2-3 minutes. The 10-minute EC50 for CNS effects was listed as 200,000 ppm (equivalent to 124,560 mg/kg/day) for the rat.

Several tests were found measuring the cardiopulmonary toxicity of isobutane. No effects were seen in anesthetized Rhesus monkeys exposed for 5 minutes to 5% isobutane through a tracheal cannula. Effects on the heart were shown in the dog with concentration-related decreased Start Printed Page 5689contractility, pressure, and output measured between 2-10% isobutane. Mongrel dogs were also anesthetized and exposed to isobutane through a tracheal cannula. Blood pressure and heart rate were not affected by exposure. All concentrations significantly increased pulmonary resistance and decreased pulmonary compliance. Similarly, anesthetized male Osburn-Mendel rats exposed to 27% isobutane showed apnea after 8.7 minutes of exposure followed by cardiac arrest; decreased respiratory rate, tidal volume, and pulmonary compliance and increased airway resistance were also found. In another test with anesthetized male Swiss mice, 20-40% isobutane did not induce cardiac arrhythmia, but did sensitize the heart to epinephrine-induced arrhythmia.

No evidence of an increase in mutation frequency was found in five strains of Salmonella typhimurium exposed to up to 50% isobutane in air. Strains TA98, TA100, TA1535, TA1537, and TA1538 were exposed for 6 hours with and without metabolic activation. No chronic toxicity or carcinogenicity studies with isobutane were identified. However, the concern for carcinogenicity is low based on rapid metabolism, lack of mutagenicity and lack of systemic toxicity at doses up to 1,867 mg/kg/day. In addition, the Agency used a qualitative structure activity relationship (SAR) database, DEREK11, to determine if there were structural alerts suggestive of carcinogenicity. No structural alerts were identified.

Specific information on the studies received and the nature of the adverse effects caused by, as well as the no-observed-adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-level (LOAEL) from the toxicity studies can be found at http://www.regulations.gov in the document “PC Code 800015: Isobutane (CAS Reg. No. 75-28-5); Human Health Risk Assessment and Ecological Effects Assessment to the Support Proposed Exemption from the Requirement of a Tolerance When Used as an Inert Ingredient in Pesticide Formulations” at [6] in docket ID number EPA-HQ-OPP-2009-0676.

B. Toxicological Points of Departure/Levels of Concern

Due to the low potential hazard of isobutane, quantitative dietary, occupational and residential exposure assessments are not necessary. In a 4-week sub-chronic toxicity study combined with reproduction/developmental toxicity screening and neurotoxicity screening study, exposure of male and female rats to target concentrations of 900, 3,000 or 9,000 ppm (equivalent to 560, 1,867, and 5,600 mg/kg/day) of isobutane by whole-body inhalation for four weeks resulted in no general systemic/neurotoxic effects. Based on decreased male and female fertility and increased post-implantation loss in the 5,600 mg/kg/day group, the fertility and reproductive endpoints NOAEL was determined to be 1,867 mg/kg/day. There were no effects on offspring survival, body weight and development up to post-natal day 4. A NOAEL of 5,600 mg/kg/day was concluded for developmental effects. Since no toxicity was observed at high doses, quantitative risk assessment is deemed unnecessary.

C. Exposure Assessment

No hazard was identified for the acute and chronic dietary assessment (food and drinking water), or for the short-, intermediate-, and long-term residential assessments, and therefore no aggregate risk assessments were performed. Available toxicological studies indicate lack of systemic toxicity at doses up to 1,867 mg/kg/day. Therefore, no quantitative dietary or occupational and residential risk assessment was conducted.

1. Dietary exposure from food and feed uses and drinking water. In evaluating dietary exposure to isobutane, EPA considered exposure under the proposed exemption from the requirement of a tolerance. Since toxicity effects were seen only at high doses for isobutane, a quantitative exposure assessment for isobutane was not conducted. Any possible dietary exposure to isobutane from its use as an inert ingredient in pesticide products would be through consumption of food to which pesticide products containing it have been applied and possibly through drinking water (from runoff). Isobutane is expected to exist in the atmosphere as a gas and volatilize rapidly from surface water and soil. This will reduce the amount of isobutane that is available for uptake by plants. Run-off into surface water is not anticipated due to rapid volatization, and therefore, contributions of concern to drinking water are not expected.

2. From non-dietary exposure. The term “residential exposure” is used in this document to refer to non-occupational, non-dietary exposure (e.g., textiles (clothing and diapers), carpets, swimming pools, and hard surface disinfection on walls, floors, tables).

Isobutane is widely used as a propellant in a variety of household products, such as cleaners and air fresheners. It is also used in nonfood use insecticide products and personal care products. Considering the low toxicity of isobutane, residues of concern are not anticipated from residential exposures (inhalation and dermal) and therefore a quantitative aggregate risk assessment was not performed.

3. Cumulative effects from substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) of 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.”

EPA has not found isobutane to share a common mechanism of toxicity with any other substances, and does not appear to produce a toxic metabolite produced by other substances. For the purposes of this tolerance action, therefore, EPA has assumed that isobutane does not have a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see EPA's Web site at http://www.epa.gov/​pesticides/​cumulative.

D. Safety Factor for Infants and Children

Section 408 of the FFDCA provides that EPA shall apply an additional tenfold (10X) margin of safety for infants and children in the case of threshold effects to account for prenatal and postnatal toxicity and the completeness of the database on toxicity and exposure unless EPA determines that a different margin of safety will be safe for infants and children. This additional margin of safety is commonly referred to as the FQPA safety factor (SF). In applying this provision, EPA either retains the default value of 10X or uses a different additional safety factor when reliable data available to EPA supports the choice of a different factor.

The toxicity database is sufficient for isobutane and potential exposure is adequately characterized given the low toxicity of the chemical. In terms of hazard, there are low concerns and no residual uncertainties regarding prenatal and/or postnatal toxicity. In the OECD 422 study via the inhalation route, the NOAEL for general systemic toxicity and neurotoxicity was 5,600 mg/kg/day (the highest dose tested). Based on decreased male and female fertility and increased post-implantation loss in the Start Printed Page 56905,600 mg/kg/day group, the fertility and reproductive endpoints NOAEL was determined to be 1,867 mg/kg/day. There were no effects on offspring survival, body weight and development up to post-natal day 4. A NOAEL of 5,600 mg/kg/day was concluded for developmental effects. Based on this information, there is no concern at this time for increased sensitivity to infants and children to isobutane when used as an inert ingredient in pesticide formulations and a safety factor analysis has not been used to assess risk. For the same reason, EPA has determined that an additional safety factor is not needed to protect the safety of infants and children.

E. Aggregate Risks and Determination of Safety

Given the lack of concern for hazard posed by isobutane, EPA concludes that there are no dietary or aggregate dietary/non-dietary risks of concern as a result of exposure to isobutane in food and water or from residential exposure. Residues of concern are not anticipated for dietary exposure (food and drinking water) or for residential exposure (dermal and inhalation) from the use of isobutane as an inert ingredient in pesticide products. As discussed above, EPA expects aggregate exposure to isobutane to pose no appreciable dietary risk given that the data show a lack of any systemic toxicity at doses up to 1,867 mg/kg/day and a lack of any apparent developmental effects.

Taking into consideration all available information on isobutane, EPA has determined that there is a reasonable certainty that no harm to any population subgroup, including infants and children, will result from aggregate exposure to isobutane under reasonable foreseeable circumstances. Therefore, the establishment of an exemption from tolerance under 40 CFR 180.910 for residues of isobutane when used as an inert ingredient in pesticide formulations applied pre- and post-harvest and under 40 CFR 180.930 for residues of isobutane when used as an inert ingredient in pesticide formulations applied to animals, is safe under FFDCA section 408.

V. Other Considerations

A. Analytical Enforcement Methodology

An analytical method is not required for enforcement purposes since the Agency is establishing an exemption from the requirement of a tolerance without any numerical limitation.

B. International Residue Limits

In making its tolerance decisions, EPA seeks to harmonize U.S. tolerances with international standards whenever possible, consistent with U.S. food safety standards and agricultural practices. EPA considers the international maximum residue limits (MRLs) established by the Codex Alimentarius Commission (Codex), as required by FFDCA section 408(b)(4). The Codex Alimentarius is a joint U.N. Food and Agriculture Organization/World Health Organization food standards program, and it is recognized as an international food safety standards-setting organization in trade agreements to which the United States is a party. EPA may establish a tolerance that is different from a Codex MRL; however, FFDCA section 408(b)(4) requires that EPA explain the reasons for departing from the Codex level.

The Codex has not established a MRL for isobutane.

VI. Conclusions

Therefore, an exemption from the requirement of a tolerance is established under 40 CFR 180.910 and 40 CFR 180.930 for isobutane (CAS Reg. No. 75-28-5) when used as an inert ingredient (propellant) in pesticide formulations applied pre- and post-harvest and when applied to animals.

VII. Statutory and Executive Order Reviews

This final rule establishes a tolerance under section 408(d) of FFDCA in response to a petition submitted to the Agency. The Office of Management and Budget (OMB) has exempted these types of actions from review under Executive Order 12866, entitled Regulatory Planning and Review (58 FR 51735, October 4, 1993). Because this final rule has been exempted from review under Executive Order 12866, this final rule is not subject to Executive Order 13211, entitled Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use (66 FR 28355, May 22, 2001) or Executive Order 13045, entitled Protection of Children from Environmental Health Risks and Safety Risks (62 FR 19885, April 23, 1997). This final rule does not contain any information collections subject to OMB approval under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et seq., nor does it require any special considerations under Executive Order 12898, entitled Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations (59 FR 7629, February 16, 1994).

Since tolerances and exemptions that are established on the basis of a petition under section 408(d) of FFDCA, such as the tolerance in this final rule, do not require the issuance of a proposed rule, the requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply.

This final rule directly regulates growers, food processors, food handlers, and food retailers, not States or Tribes, nor does this action alter the relationships or distribution of power and responsibilities established by Congress in the preemption provisions of section 408(n)(4) of FFDCA. As such, the Agency has determined that this action will not have a substantial direct effect on States or Tribal governments, on the relationship between the national government and the States or Tribal governments, or on the distribution of power and responsibilities among the various levels of government or between the Federal Government and Indian Tribes. Thus, the Agency has determined that Executive Order 13132, entitled Federalism (64 FR 43255, August 10, 1999) and Executive Order 13175, entitled Consultation and Coordination with Indian Tribal Governments (65 FR 67249, November 9, 2000) do not apply to this final rule. In addition, this final rule does not impose any enforceable duty or contain any unfunded mandate as described under Title II of the Unfunded Mandates Reform Act of 1995 (UMRA) (Pub. L. 104-4).

This action does not involve any technical standards that would require Agency consideration of voluntary consensus standards pursuant to section 12(d) of the National Technology Transfer and Advancement Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note).

VIII. Congressional Review Act

The Congressional Review Act, 5 U.S.C. 801 et seq., generally provides that before a rule may take effect, the agency promulgating the rule must submit a rule report to each House of the Congress and to the Comptroller General of the United States. EPA will submit a report containing this rule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States prior to publication of this final rule in the Federal Register. This final rule is not a “major rule” as defined by 5 U.S.C. 804(2).

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List of Subjects in 40 CFR Part 180

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Dated: January 24, 2011.

Lois Rossi,

Director, Registration Division, Office of Pesticide Programs.

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Therefore, 40 CFR chapter I is amended as follows:

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PART 180—[AMENDED]

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

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Authority: 21 U.S.C. 321(q), 346a and 371.

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2. In the table to § 180.910 add alphabetically a new inert ingredient to read as follows:

End Amendment Part
Inert ingredients used pre- and post-harvest; exemptions from the requirement of a tolerance.
* * * * *
Inert ingredientsLimitsUses
*         *         *         *         *         *         *
Isobutane (CAS Reg. No. 75-28-5)NonePropellant.
*         *         *         *         *         *         *
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3. In the table to § 180.930, add alphabetically a new inert ingredient to read as follows:

End Amendment Part
Inert ingredients applied to animals; exemptions from the requirement of a tolerance.
* * * * *
Inert ingredientsLimitsUses
*         *         *         *         *         *         *
Isobutane (CAS Reg. No. 75-28-5)NonePropellant.
*         *         *         *         *         *         *
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[FR Doc. 2011-2265 Filed 2-1-11; 8:45 am]

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