Air Quality State Implementation Plans; Approvals and Promulgations: Michigan; Revisions to Part 1 and 2 Rules

Air Plan Approval; Michigan; Revisions to Part 1 and 2 Rules

Supplementary Information

Throughout this document whenever "we," "us," or "our" is used, we mean EPA.

I. Background

Section 110(a)(2)(C) of the Clean Air Act (CAA) requires that the SIP include a program to provide for the "regulation of the modification and construction of any stationary source within the areas covered by the plan as necessary to assure that National Ambient Air Quality Standards (NAAQs) are achieved." This includes a program for permitting construction and modification of both major and minor sources that the state deems necessary to protect air quality. The State of Michigan's minor source permit to install rules are contained in Part 2, Air Use Approval, R. 336.1201 to R. 336.1299 of the Michigan Administrative Code. Changes to the Part 2 rules were submitted on November 12, 1993; May 16, 1996; April 3, 1998; September 2, 2003; March 24, 2009; February 28, 2017; and March 8, 2022. EPA approved changes to the Part 2 rules most recently in a final approval dated April 27, 2023 (88 FR 25498).

On September 27, 2022 (87 FR 58471), EPA proposed approval, via a direct final rule, of the Michigan SIP revisions submitted on March 8, 2022. During the public comment period, EPA received an adverse comment on the Michigan rule revisions to R 336.1285 "Permit to install exemptions; miscellaneous" and R 336.1291, "Permit to install exemptions; emission units with 'de minimis' emissions". On November 14, 2022 (87 FR 68634), EPA withdrew the direct final rule. EPA approved the revisions to the Michigan rule revision which did not receive adverse comment (88 FR 25498, April 27, 2023). As explained in that action, we did not consider the comments received to be germane or relevant to EPA's proposal to approve portions of Michigan's Part 1 and Part 2 rules beyond the permit exemption rules, and therefore not adverse to approving them into the Michigan SIP.

EPA is now proposing to approve Michigan's rules R 336.1285(2)(oo) and R 336.1291 into the Michigan SIP. On November 14, 2023, Michigan submitted a supplement to the original March 8, 2022, submittal by supplying additional information regarding the approval of Michigan rules R 336.1285(2)(oo) and R 336.1291 in response to comments we received on the rulemaking. These rules exempt certain processes and/or equipment from Michigan's minor New Source Review permitting program. The November 14, 2023, Michigan supplemental submittal as well as the original March 8, 2022, submittal are available with the docket for this rulemaking action.

Michigan Rule R 336.1285(2)(oo)

Michigan rule R 336.1285(2)(oo) exempts vapor intrusion mitigation systems. Specifically, this exemption applies to equipment or systems, or both, used exclusively to mitigate vapor intrusion of an indoor space that is not on the property where the release of the hazardous substance occurred, and which has an exhaust that meets all of the following requirements:

i. Unobstructed vertically upward.

ii. At least 12 inches above the nearest eave of the roof or at least 12 inches above the surface of the roof at the point of penetration.

iii. More than 10 feet above the ground.

iv. More than 2 feet above or more than 10 feet away from windows, doors, other buildings, and other air intakes.

Michigan Rule R 336.1291

Michigan rule R 336.1291 exempts emission units with "de minimis" emissions. Specifically, rule R 336.1291 requires that records be maintained providing a description of the emission unit(s), and documentation and/or calculations identifying the quality, nature, and quantity of the air contaminant emissions are maintained in sufficient detail to demonstrate that the potential emissions are less than those listed in the table of air contaminants applicable to this exemption. Michigan's rule R 336.1291 exemption is based on the units' potential to emit. Potential to emit is defined in Michigan's rule 336.2801(hh) as:

"(T)he maximum capacity of a stationary source to emit a pollutant under its physical and operational design. A physical or operational limitation on the capacity of the source to emit a pollutant, including air pollution control equipment and restrictions on hours of operation or on the type or amount of material combusted, stored, or processed, shall be treated as part of its design if the limitation or the effect it would have on emissions is legally enforceable and enforceable as a practical matter by the state, local air pollution control agency, or United States Environmental Protection Agency. Secondary emissions do not count in determining the potential to emit of a stationary source."

In Michigan's November 14, 2023, supplemental submittal, Michigan provides an analysis of the rule revisions and addresses comments raised in the October 27, 2022, letter. Michigan's analysis included responses to the commenter's points including: 1) the section 110(l) analysis must consider the program as a whole; 2) Michigan cannot rely on the Tribal rule thresholds; 3) Michigan did not demonstrate that annual potential to emit limitations sufficiently protect short-term NAAQS; 4) Michigan's justification for not having more stringent thresholds in non-attainment areas does not hold up; and 5) Michigan's representation of its actual emission exemptions are insufficient.

To demonstrate that the two exemptions would not interfere with any applicable requirement concerning the attainment and reasonable further progress, or any other applicable requirement, Michigan reviewed its Michigan Air Emissions Reporting System (MAERS). The Michigan rule 291 exemption has been in effect in the state since 2016. The MAERS data contains information on a specific subset of emission units that are exempt. As described in the table of emission unit and pollutant levels for various exemptions in Michigan's supplemental submittal, of those facilities that are reporting, Michigan rule 291 emission units are responsible for less than 0.9 percent of volatile organic compound emissions from all units reported to MAERS, and less than 3.6 percent of volatile organic compound emissions from exempt units reported in MAERS. Requiring Michigan to permit these exempt units would not contribute to Michigan's plan for attainment or reasonable further progress, but would rather divert Michigan air permitting program resources from addressing other more significant air pollutant emitters. The air permit exemptions have been in effect for several years and have had no measurable impact on attainment or reasonable further progress.

Section 110(l) Demonstration

As part of the SIP revision request supplemental submittal, Michigan submitted a 110(l) demonstration. Section 110(l) of the CAA governs the submittal of SIP revisions. Each revision to an implementation plan submitted by a State shall be adopted by the State after reasonable notice and public hearing. The Administrator shall not approve a revision of a plan if the revision would interfere with any applicable requirement concerning the attainment and reasonable further progress (as defined by 40 CFR 7501), or any other applicable requirement of this chapter.

As part of its 110(l) demonstration, Michigan provided an analysis of the emission exemptions impacts, using the Modeled Emission Rates for Precursors as a Tier 1 Demonstration Tool to demonstrate ozone and fine particulate (PM _2.5 ) impacts from single sources on secondary pollutants for the Prevention of Significant Deterioration (PSD) permitting program, from the sources using Michigan rule 291 exemption air emissions.

Michigan evaluated the air quality impact that Michigan Rule 291 would have on ozone and secondary PM _2.5 formation. Michigan used the method set forth in EPA's April 30, 2019, Guidance on the Development of Modeled Emission Rates for Precursors (MERPs) as a Tier 1 Demonstration Tool for Ozone and PM_2.5under the PSD Permitting Program (MERPs guidance) to estimate source specific contributions to ozone and secondary PM _2.5 formation.

As part of its analysis, Michigan utilized hypothetical source modeling that EPA used to illustrate the framework established in the MERPs guidance. Hypothetical sources, modeled emission rates, and modeled air quality impacts were obtained using EPA's MERPs View Qlik tool . For its analysis, Michigan considered hypothetical sources located in Michigan. A hypothetical source was selected for this analysis if the hypothetical source has the lowest MERP for a given precursor pollutant. For a given precursor pollutant, a lower MERP suggests that the precursor pollutant more readily forms the secondary pollutant. As a result, choosing a lower MERP more conservatively estimates the air quality impacts for the secondary pollutant since the source has a higher modeled air quality impact for a given modeled emission rate. For all precursor pollutants except VOC as a precursor to ozone, Michigan utilized modeling results from the Montcalm County, Michigan hypothetical source. For VOC as a precursor to ozone, Michigan utilized the Marquette County, Michigan, hypothetical source. For all precursor pollutants, Michigan chose the hypothetical source in Michigan with the lowest MERP for a given precursor pollutant. Using the modeled results for the Marquette and Montcalm County, Michigan, hypothetical sources, Michigan evaluated the air quality impacts associated with the emission thresholds for Michigan Rule 291 using a method that was consistent with the framework recommended in the MERPs guidance.

For the single emission unit impact analysis, Michigan evaluated a proposed project that would emit 10 tons per year of sulfur dioxide (SO ₂ ), 10 tons per year of nitrogen oxides (NO _X ), and 5 tons per year of volatile organic compounds (VOC). This is the maximum emission rate that would be allowed for a single emission unit under Michigan Rule 291. Based on its single emission unit impact analysis, Michigan determined that ozone impacts would be 0.047 parts per billion (ppb), annual PM _2.5 impacts would be 0.000413 micrograms per cubic meter (μg/m ³ ), and 24-hour PM _2.5 impacts would be 0.0155 μg/m ³ .

For the multiple emission unit impact analysis, Michigan evaluated a proposed project that would emit 40 tons of SO ₂ , 40 tons per year of NO _X , and 40 tons per year of VOC. This is the maximum emission rate that would be allowed for multiple emission units that are part of the same project without being considered significant as defined under Michigan Rule 119(e). Based on its multiple emission unit impact analysis, Michigan determined that 8-hour ozone impacts would be 0.20 ppb, annual PM _2.5 impacts would be 0.00165 μg/m ³ , and 24-hour PM _2.5 impacts would be 0.062 μg/m ³ .

EPA believes that Michigan's goal of reducing permitting workload on Michigan permitting staff by utilizing these permit exemptions would not interfere with Michigan's air program since any permitting of these exempt units would not impose any additional air pollution controls due to the de minimus level of the exempted unit's air emissions. The amount of emissions from these exempt units do not interfere with continued Michigan's attainment nor reasonable further progress, or any other applicable requirement of the NAAQs.

The 110(l) demonstration in the SIP revision request adequately addresses this requirement and will have no effect on Michigan's NAAQS attainment status, or any backsliding on achieved improvements. The Michigan air permit exemptions do not apply to any activity that is subject to PSD of air quality regulations or new source review for major sources in non-attainment areas regulations. As Michigan has stated in its supplemental submittal, the exemptions have not had any measurable or discernable impact on attainment. The exemptions specified do not apply to the construction, modification, or reconstruction of a new major source of hazardous air pollutants as defined in the Federal requirements of 40 CFR parts 61 and 63, or any other applicable requirement or existing program limitation. By including such language in Michigan's minor source regulations, Michigan has attempted to address any sources that may have significant emissions and the potential to negatively impact ambient air quality. This approach ensures that sources that might otherwise be exempt from permitting are subject to minor NSR permitting. States must develop minor NSR programs to attain and maintain the NAAQS and the Federal requirements for state minor NSR programs are outlined in 40 CFR 51.160 through 51.164. These Federal requirements for minor NSR programs are considerably less prescriptive than those for major sources and, as a result, there is a larger variation of requirements across the state minor NSR programs. The air permit exemptions allow Michigan to allocate its limited resources to address sources in air permitting by avoiding the permitting of small sources with no perceivable impact on attainment. Michigan's November 14, 2023, supplemental submittal demonstrates that its minor NSR program will adequately protect the NAAQs with the additional exemptions to the already approved air permit rule exemptions in its SIP.

II. What Action is EPA Taking?

EPA is proposing approval of revisions to Michigan's Part 2 regulations, specifically Michigan Air Pollution Control Rules R 336.1285(2)(oo) and R 336.1291.

III. Incorporation by Reference

In this rule, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference Michigan rules R 336.1285(2)(oo) and R 336.1291, effective 1/2/2019 and 12/20/2016 respectively, discussed in section I. of this preamble. EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

IV. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993), and 14094 (88 FR 21879, April 11, 2023);

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and
• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Executive Order 12898 (Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations, 59 FR 7629, February 16, 1994) directs Federal agencies to identify and address "disproportionately high and adverse human health or environmental effects" of their actions on minority populations and low-income populations to the greatest extent practicable and permitted by law. EPA defines environmental justice (EJ) as "the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies." EPA further defines the term fair treatment to mean that "no group of people should bear a disproportionate burden of environmental harms and risks, including those resulting from the negative environmental consequences of industrial, governmental, and commercial operations or programs and policies."

EGLE did not evaluate environmental justice considerations as part of its SIP submittal; the CAA and applicable implementing regulations neither prohibit nor require such an evaluation. EPA did not perform an EJ analysis and did not consider EJ in this action. Consideration of EJ is not required as part of this action, and there is no information in the record inconsistent with the stated goal of E.O. 12898 of achieving environmental justice for people of color, low-income populations, and Indigenous peoples.

[FR Doc. 2024-08798 Filed 4-24-24; 8:45 am]

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