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Pesticides; Guidance on Phenol Resistance Testing for Antimicrobial Disinfectant and Sanitizer Pesticides

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Information about this document as published in the Federal Register.

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Environmental Protection Agency (EPA).


Notice of availability.


The Agency is announcing the availability of guidance titled ``Elimination of Phenol Resistance Testing for Antimicrobial Disinfectant and Sanitizer Pesticides.'' This final Pesticide Registration (PR) Notice provides guidance to registrants concerning the discontinuation of phenol resistance testing as a part of efficacy testing for antimicrobial disinfectants and sanitizers. Adoption of this guidance will eliminate unnecessary testing and will result in resource savings for both the Agency and registrants. Responses to public comments received in response to the previously issued draft guidance are also being made available.

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Michele Wingfield, Antimicrobials Division, (7510C), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703) 308-6349; fax number: (703) 308-8481; e-mail address:

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I. General Information

A. Does this Action Apply to Me?

This action is directed to the public in general. Although this action may be of particular interest to those persons who manufacture or formulate pesticides. Since other entities may also be interested, the Agency has not attempted to describe all the specific entities that may be affected by this action. If you have any questions regarding the information in this notice, consult the person listed under FOR FURTHER INFORMATION CONTACT.

B. How Can I Get Additional Information, Including Copies of this Document and Other Related Documents? -

1. Electronically. You may obtain electronic copies of this document, the PR Notice, and the Agency's response to public comments from the Office of Pesticide Programs' Home Page at​pesticides/​. You can also go directly to the listings from the EPA Internet Home Page at​. To access this document, on the Home Page select “Laws and Regulations,” “Regulations and Proposed Rules,” and then look up the entry for this document under the “Federal Register—Environmental Documents.” You can also go directly to the Federal Register listings at​fedrgstr/​. -

2. Fax-on-demand. You may request a faxed copy of the Pesticide Registration (PR) Notice titled “Elimination of Phenol Resistance Testing for Antimicrobial Disinfectant and Sanitizer Pesticides,” by using a faxphone to call (202) 401-0527 and selecting item 6139. You may also follow the automated menu. -

3. In person. The Agency has established an official record for this action under docket control number OPP-00706. The official record consists of the documents specifically referenced in this action, any public comments received during an applicable comment period, and other information related to this action, including any information claimed as confidential business information (CBI). This official record includes the documents that are physically located in the docket, as well as the documents that are referenced in those documents. The public version of the official record does not include any information claimed as CBI. The public version of the official record, which includes printed, paper versions of any electronic comments submitted during an applicable comment period, is available for inspection in the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal Start Printed Page 34637holidays. The PIRIB telephone number is (703) 305-5805.

II. Background

A. What Guidance Does this PR Notice Provide? -

The PR Notice announces the discontinuation of phenol resistance testing as a part of efficacy testing for antimicrobial disinfectants and sanitizers. The Agency will now consider registering or reregistering antimicrobial disinfectant or sanitizer pesticides without supporting phenol resistance testing. All other data in support of registration or reregistration, including any required efficacy testing data, would also need to be submitted and accepted by the Agency.

-Phenol resistance testing is a standard that has traditionally been used to estimate the intrinsic resistance or sensitivity of some test bacteria to chemical disinfectants and sanitizers. For years, the Agency has been aware of the lack of standard and uniform resistance levels to phenol expressed by the test cultures used in the existing Official Methods of Analysis of the Association of Official Analytical Chemists (AOAC) test methods. Historically, the inability to maintain and propagate test cultures that express standard and uniform levels of phenol resistance has been a recognized scientific problem which has persisted for at least 70 years. Furthermore, the inability of many reputable and competent testing facilities to achieve consistent test results with the phenol resistance standard has prompted both concern and action by the Agency.

-On September 10, 1997, after internal scientific deliberation, the Agency placed before the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) the following question regarding phenol resistance:

What scientific direction should be taken regarding the lack of standard and uniform resistance levels to phenol of the test cultures used in the existing AOAC (Association of Official Analytical Chemists) efficacy test methods? Should the Agency:

  • Totally eliminate the phenol resistance requirement; or
  • Modify the required phenol resistance patterns to provide a broader range of acceptable resistance; or
  • Replace the phenol resistance requirements with some other procedures that assure hardiness and equivalence to test cultures, such as standard, quantitative inoculum level?

-Briefly, the SAP responded that there is no current relevance to requiring the phenol resistance test and, therefore, the phenol coefficient method should be eliminated and new protocols should be established for defining the conditions for culturing test microorganisms with suitable resistance levels to antimicrobials.

-Subdivision G of the Pesticide Assessment Guidelines, part 91-1, describes the general product performance (efficacy) standards for disinfectants and sanitizers. Subsection (b)(3)(I) of part 91-1 refers to the AOAC standard tests that may be used to satisfy the data requirements of 40 CFR 158.640. In turn, these AOAC tests include references to phenol resistance testing.

-The Agency concurs with the SAP, which has engaged in considerable discussion and deliberation, internally and with members of the scientific and regulated communities, on how to best proceed. Given the inapplicability of a test organism's resistance to phenol when disinfectants or sanitizers are tested for their efficacy performance, the Agency no longer requires submission of testing to demonstrate compliance with AOAC-specified levels of expressed phenol resistance by test microorganisms during the efficacy evaluation of disinfectants or sanitizers. However, as an interim measure while method development research continues, the Agency recommends a minimum inoculum level of 104 colony forming units per carrier for all test microorganisms when the AOAC carrier based tests are used.

B. PR Notices are Guidance Documents -

The PR Notice discussed in this notice is intended to provide guidance to EPA personnel and decision-makers and to pesticide registrants. This notice is not binding on either EPA or pesticide registrants, and EPA may depart from the guidance where circumstances warrant and without prior notice. Likewise, pesticide registrants may assert that the guidance is not appropriate generally or not applicable to a specific pesticide or situation.

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List of Subjects

  • Environmental protection
  • Administrative practice and procedure
  • Agricultural commodities
  • Pesticides and pests
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Dated: June 19, 2001.

Marcia E. Mulkey,

Director, Office of Pesticide Programs

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[FR Doc. 01-16442 Filed 6-28-01; 8:45 am]