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 Environmental Protection Agency [EPA-HQ-OAR-2007-1196; FRL-11653-01-OAR]
 AGENCY: Environmental Protection Agency (EPA).
 ACTION: Notice of availability.
 SUMMARY: This notice announces the broadly applicable alternative test method approval decisions that the Environmental Protection Agency (EPA) made under and in support of New Source Performance Standards (NSPS) and the National Emission Standards for Hazardous Air Pollutants (NESHAP) between January 1, 2023, and December 31, 2023.
 FOR FURTHER INFORMATION CONTACT: An electronic copy of each alternative test method approval document is available at 
                        *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*.  For questions about this notice, contact Mr. Steffan Johnson, Air Quality Assessment Division, Office of Air Quality Planning and Standards (E143-02), Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number: (919) 541-4790; email address:
                        *johnson.steffan@epa.gov*. For technical questions about individual alternative test method decisions, refer to the contact person identified in the individual approval document(s).


SUPPLEMENTARY INFORMATION: I. General Information A. Does this notice apply to me? This notice will be of interest to entities regulated under 40 Code of Federal Regulations (CFR) parts 59, 60, 61, 63 and 65; state, local, and tribal agencies; and the EPA Regional offices responsible for implementation and enforcement of regulations under 40 CFR parts 59, 60, 61, 63, and 65. B. How can I get copies of this information? You may access copies of the broadly applicable alternative test method approval documents at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*. II. Background This notice identifies broadly applicable alternative test methods that the EPA approved in 2023 under the NSPS, 40 CFR part 60, and the NESHAP and 40 CFR part 63 programs. See Table 1 of this notice for the summary of these test methods. Source owners and operators may voluntarily use these broadly applicable alternative test methods in lieu of otherwise required test methods or related testing procedures. Use of these broadly applicable alternative test methods are not intended to, and should not, change the applicable emission standards. The Administrator has the authority to approve the use of alternative test methods for compliance with requirements under 40 CFR parts 59, 60, 61, 63, and 65. This authority is found in 40 CFR 60.8(b)(3), 61.13(h)(1)(ii), and 63.7(e)(2)(ii). Additional and similar authority can be found in 40 CFR 59.104(f) and 65.158(a)(2). The criteria for approval and procedures for submission and review of broadly applicable alternative test methods are explained in a previous 
                    **Federal Register**
                     notice published at 72 FR 4257 (January 30, 2007) and located at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*. As explained in this notice, we will announce approvals for broadly applicable alternative test methods at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*
                     as they are issued and publish an annual notice that summarizes approvals for broadly applicable alternative test methods during the preceding year. As also explained in the January 30, 2007 notice, our approval decisions involve thorough technical reviews of numerous source-specific requests for alternatives and modifications to test methods and procedures. Based on these reviews, we have often found that these modifications or alternatives would be equally valid and appropriate to apply to other sources within a particular class, category, or subcategory. Consequently, we have concluded that where either a method modification or an alternative method is clearly broadly applicable to a class, category, or subcategory of sources, it is both equitable and efficient to 
                    ( print page 4943)
                    simultaneously approve its use for all appropriate sources and situations. Use of approved alternative test methods is not mandatory but rather permissive. Sources are not required to employ such a method but may choose to do so in appropriate circumstances. As specified in 40 CFR 63.7(f)(5), however, a source owner or operator electing to use an alternative method for 40 CFR part 63 standards must continue to use the alternative method until otherwise authorized. Source owners or operators should, therefore, review the specific broadly applicable alternative method approval decision at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*
                     before electing to employ any alternative method. Source owners or operators choosing to use a broadly applicable alternative should also notify their regulatory agency prior to using the alternative. III. Approved Alternative Test Methods and Modifications to Test Methods This notice specifies five broadly applicable alternative test methods that the EPA approved between January 1, 2023, and December 31, 2023. The alternative method decision letter/memo designation numbers, test methods affected, sources allowed to use this alternative, and method modifications or alternative methods allowed are summarized in Table 1 of this notice. A summary of approval documents was previously made available on our Technology Transfer Network between January 1, 2023, and December 31, 2023. For more detailed information, please refer to the complete copies of these approval documents available at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*. As also explained in our January 30, 2007 notice, we will revisit approvals of alternative test methods in response to written requests or objections indicating that a particular approved alternative test method either should not be broadly applicable or that its use is not appropriate or should be limited in some way. Any objection to a broadly applicable alternative test method, as well as the resolution of that objection, will be announced at 
                    *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*
                     and in a subsequent 
                    **Federal Register**
                     notice. If we decide to retract a broadly applicable test method, we will likely consider the need for an appropriate transition period for users either to request case-by-case approval or to transition to an approved method. Richard A. Wayland, Director, Air Quality Assessment Division.
 Table 1—Approved Alternative Test Methods and Modifications to Test Methods Referenced in or Published Under Appendices in 40 CFR Parts 60 and 63 Posted Between January 2023 and December 2023 
                        a
Alternative method decision letter/memo number
As an alternative or
                             modification to . . .
For . . .
You may . . .ALT-151
EPA Method 3A as an alternative method for EPA Method 3B
Testing of regulated sources requiring the use of EPA Method 3B in 40 CFR, parts 59, 60, 61, 63 and 65
Use EPA Method 3A instead of EPA Method 3B, whenever required to use Method 3B in any regulation contained within 40 CFR, parts 59, 60, 61, 63 and 65.ALT-152
Certification of candidate Method 9 observers through use of a virtual reality (VR) headset
Use of a VR headset-based alternative method for conducting Method 9 plume demonstrations and certification as described in this letter and further detailed in Attachment A as an alternative to the procedures of section 3.2 of Method 9 with specific limitations, as listed in the letter
Use the VR headset-based alternative method for conducting Method 9 plume demonstrations and certification as described in this letter and further detailed in Attachment A as an alternative to the procedures of section 3.2 of Method 9.ALT-153
EPA Method 3A as an alternative method for EPA Method 3B integrated bag analysis
Calculation of stack gas molecular weight and/or diluent correction to measured pollutant concentrations
Use analysis procedures similar to those found in Method 3A to analyze the bag sample(s) collected according to Method 3B.ALT-154
ASTM E-2515 filter gravimetric pre/post-test filter mass assessments per method direction in section 9.4.4
Consistent measurement of filter media and associated gaskets, as a paired set, to lower overall measurement uncertainty
Desiccate and perform the pre-test processing (taring) of filters in pairs as is currently allowed for filter gaskets in section 9.4.4 (pre-test) and 10.2.1 (post-test) when conducting testing of wood heaters under Subpart AAA and determine mass emissions.ALT-155
ASTM E-2515 dilution tunnel minimum velocity requirement as stated in section 9.2.1
The use of low flow manometers to measure flow velocities as low as 180 fpm during certain PM measurement tests
Measure velocities as low as 180 fpm, in a dilution tunnel greater than 8′′ diameter, using a Ptype pitot tube and a micromanometer gauge more sensitive than the method specified 0.001′′ of water such as a manometer with resolution to 0.0005 inches of water or less.a
                         Source owners or operators should review the specific broadly applicable alternative method approval letter at 
                        *https://www.epa.gov/​emc/​broadly-applicable-approved-alternative-test-methods*
                         before electing to employ any alternative test method.


[FR Doc. 2024-01495 Filed 1-24-24; 8:45 am] BILLING CODE 6560-50-P