Air Plan Disapproval; Missouri; Control of Sulfur Dioxide Emissions

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing to disapprove revisions to the Missouri State Implementation Plan (SIP) submitted by Missouri on March 7, 2019. In its submission, Missouri requested rescinding a regulation addressing sulfur compounds from the SIP and replacing it with a new regulation that establishes requirements for units emitting sulfur dioxide (SO₂). The EPA is proposing to disapprove the SIP revision because the state has not demonstrated that the removal of SO₂ emission limits for the Evergy-Hawthorn (Hawthorn, formerly Kansas City Power & Light-Hawthorn) and Ameren Labadie (Labadie) power plants from the SIP would not interfere with National Ambient Air Quality Standard (NAAQS) attainment and reasonable further progress (RFP), or any other applicable requirement of the Clean Air Act (CAA) as required under CAA section 110(l). This disapproval action is being taken under the CAA to maintain the stringency of the SIP and preserve air quality.

DATES:

Comments must be received on or before August 8, 2022.

ADDRESSES:

You may send comments, identified by Docket ID No. EPA-R07-OAR-2022-0531 to https://www.regulations.gov . Follow the online instructions for submitting comments.

Instructions: All submissions received must include the Docket ID No. for this rulemaking. Comments received will be posted without change to https://www.regulations.gov, including any personal information provided. For detailed instructions on sending comments and additional information on the rulemaking process, see the “Written Comments” heading of the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT:

Wendy Vit, Environmental Protection Agency, Region 7 Office, Air Quality Planning Branch, 11201 Renner Boulevard, Lenexa, Kansas 66219; telephone number: (913) 551-7697; email address: vit.wendy@epa.gov .

SUPPLEMENTARY INFORMATION:

Throughout this document “we,” “us,” and “our” refer to EPA.

Table of Contents

I. Written Comments

II. What is being addressed in this document?

A. Hawthorn SO₂ Emission Limit

B. Labadie SO₂ Emission Limit

III. Have the requirements for approval of a SIP revision been met?

IV. What action is the EPA proposing to take?

V. Statutory and Executive Order Reviews

I. Written Comments

Submit your comments, identified by Docket ID No. EPA-R07-OAR-2022-0531, at https://www.regulations.gov . Once submitted, comments cannot be edited or removed from Regulations.gov . The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( i.e., on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets .

II. What is being addressed in this document?

Missouri revised title 10, division 10 of the code of state regulations (CSR) by rescinding 10 CSR 10-6.260 “Restriction of Emission of Sulfur Compounds” and replacing it with a new regulation, 10 CSR 10-6.261 “Control of Sulfur Dioxide Emissions.” 10 CSR 10-6.260 was originally approved into the SIP at 40 CFR 52.1320(c) in 1998 (63 FR 45727, August 27, 1998) and has been revised several times. 10 CSR 10-6.261 has not been approved into the SIP. On March 7, 2019, the state submitted a request to revise the SIP by removing 10 CSR 10-6.260 and replacing it with 10 CSR 10-6.261 (effective date March 30, 2019). Missouri's analysis of the rescission and replacement can be found in the technical support document (TSD) submitted to the EPA on May 4, 2022 and included in this docket.

In order for the EPA to fully approve a SIP revision, the state must demonstrate that the SIP revision meets the requirements of CAA section 110(l), 42 U.S.C. 7410(l). Under CAA section 110(l), the EPA may not approve a SIP revision that would interfere with any applicable requirement concerning NAAQS attainment and RFP, or any other applicable requirement of the CAA. The EPA interprets section 110(l) such that states have two main options to make this noninterference demonstration. First, the state could demonstrate that emissions reductions removed from the SIP are replaced with new control measures that achieve equivalent or greater emissions reductions. Thus, the SIP revision will not interfere with the area's ability to continue to attain or maintain the affected NAAQS or other CAA requirements. The EPA further interprets section 110(l) as requiring such substitute measures to be quantifiable, permanent, and enforceable, among other considerations. For section 110(l) purposes, “permanent” means the state cannot modify or remove the substitute measure without EPA review and approval. Second, the state could conduct air quality modeling or develop an attainment or maintenance demonstration based on EPA's most recent technical guidance to show that, even without the control measure or with the control measure in its modified form, the area (as well as interstate and intrastate areas downwind) can continue to attain and maintain the affected NAAQS.

As discussed in detail in its TSD, Missouri contends that there are substitute measures of comparable or greater stringency to the Hawthorn and Labadie SO₂ limits, and therefore argues that removal of these emission limits from the SIP would satisfy CAA section 110(l) requirements without the need for an air quality analysis showing that removing the measures will not interfere with NAAQS attainment or other applicable requirements.

We disagree with Missouri's analysis and rationale for removing the Hawthorn and Labadie SO₂ emission limits from the SIP. The substitute SO₂ emission limit for Hawthorn is contained in a Prevention of Significant Deterioration (PSD) permit that is not approved in the SIP and could be later modified without requiring EPA approval, and therefore the substitute measure is not considered permanent. For Labadie, the substitute SO₂ emission limit is not as stringent as the limit currently in the SIP-approved 10 CSR 10-6.260, nor does it result in surplus emission reductions. In addition, Missouri has not provided an air quality analysis demonstrating the revisions related to the Labadie SO₂ emission limits in the SIP will not interfere with NAAQS attainment or other applicable requirements. For these reasons we are proposing to disapprove the rescission of 10 CSR 10-6.260 and replacement with 10 CSR 10-6.261 in the SIP.

This proposed disapproval action, if finalized, would maintain 10 CSR 10-6.260 requirements at 40 CFR 52.1320(c) as federally approved SIP obligations.

The EPA's rationale for disapproving removal of the Hawthorn and Labadie SO₂ emission limits from the SIP is further discussed in the sections below.

A. Hawthorn SO ₂ Emission Limit

Table 1 of 10 CSR 10-6.260 in the SIP includes a 30-day rolling average SO₂ emission limit of 0.12 pounds/million British thermal units (lb/MMBtu) for the Hawthorn plant. The footnote to Table 1 in 10 CSR 10-6.260 states: “The SO₂ emission rate comes from the Prevention of Significant Deterioration permit for Unit 5A and is implemented in accordance with the terms of the permit.” The referenced permit for Hawthorn is Construction Permit Number 888 issued by the Kansas City Health Department in August of 1999 and amended in 2001 after the reconstruction of the unit 5 boiler (which was renamed unit 5A). The permit contains the 30-day rolling average SO₂ emission limit of 0.12 lb/MMBtu referenced in Table 1 of 10 CSR 10-6.260, and it stipulates that the facility must achieve the limit by utilizing a dry flue gas desulfurization system and low-sulfur coal. This permit has not changed since 2001 when the reconstruction of unit 5 was completed, and the SO₂ limit has also been part of the facility's Title V operating permit since that time.

Missouri's rationale for removing the 0.12 lb/MMBtu SO₂ limit from the SIP is based on using the equivalent SO₂ emission limit in Hawthorn's PSD permit as a substitute measure. Missouri contends that removal of the 0.12 lb/MMBtu SO₂ limit from the SIP satisfies CAA section 110(l) because the same limit remains in place through Hawthorn's PSD permit. Missouri further states that any relaxation of the 30-day rolling average SO₂ emission limit in the PSD permit would subject the facility to PSD permitting requirements.

EPA disagrees with Missouri's assessment because it relies on a substitute measure from Hawthorn's PSD permit that is not SIP-approved. Although the PSD permit is federally enforceable, it is not considered permanent because it is not contained in the Missouri SIP and could be modified without requiring EPA approval. While the EPA can provide comments on PSD permits during the state's public notice period, Missouri can issue or modify PSD permits that are not in the SIP without EPA approval pursuant to the state's federally approved permitting program. Therefore, because substitute measures must be quantifiable, permanent, and enforceable to be used for 110(l) analysis purposes, EPA's approval of the removal of a SIP-approved limit based on permits that are not SIP-approved would not be consistent with CAA section 110(l).

B. Labadie SO ₂ Emission Limit

The Labadie SO₂ emission limit found at 10 CSR 10-6.260 (3)(C)3.A.(II) in the SIP is a daily average of 4.8 lb/MMBtu, which applies to each of Labadie's four boilers. In 2015, the state entered into a Consent Agreement with the operating entity to limit SO₂ emissions at Labadie. The Consent Agreement includes a facility-wide SO₂ emission limit of 40,837 pounds per hour (lb/hr) for Labadie. As stated in Missouri's TSD included in this docket, the purpose of the Consent Agreement was to strengthen the SIP related to attainment in the Jefferson County, Missouri nonattainment area for the 2010 1-hour SO₂ NAAQS. In December 2020, the state amended the 2015 Consent Agreement with an addendum to clarify that all four of Labadie's units are covered under the facility-wide SO₂ limit and incorporate the enforceable monitoring, recordkeeping, and reporting requirements associated with the facility-wide limit. The EPA approved the Consent Agreement including the limits for Labadie, as amended, into the SIP at 40 CFR 52.1320(d) on January 28, 2022 (87 FR 4508). 10 CSR 10-6.261 does not include any of the limits contained in the Consent Agreement.

Missouri's rationale for removing the 4.8 lb/MMBtu SO₂ limit from the SIP is based on using the already SIP-approved Consent Agreement SO₂ emission limit as a substitute measure of greater stringency. The state's analysis of the stringency of the Consent Agreement facility-wide SO₂ limit of 40,837 lb/hr compared to the 10 CSR 10-6.260 unit-level SO₂ limit of 4.8 lb/MMBtu assumes all four boilers are operating at their maximum hourly design rate, which is a combined total heat input of 24,580 MMBtu/hr. Labadie's maximum hourly SO₂ emissions allowed under 10 CSR 10-6.260 is calculated by multiplying 4.8 lb/hour by 24,580 MMBtu/hr, which equates to 117,984 lb/hr, nearly three times the maximum hourly emissions of 40,837 lb/hr allowed by the already SIP-approved Consent Agreement. Based on these calculations, Missouri concludes that the limit in the already SIP-approved Consent Agreement is more restrictive than the limit in 10 CSR 10-6.260, and therefore, removal of the 4.8 lb/MMBtu SO₂ emission limit from the SIP will not relax requirements for Labadie, thus satisfying CAA section 110(l).

The EPA agrees that maximum allowable facility-wide hourly SO₂ emissions for Labadie are lower under the already SIP-approved Consent Agreement than were under 10 CSR 10-6.260 alone. However, our calculations show that under a different set of assumptions, there are potential operating scenarios for Labadie in which individual units could operate at a rate greater than the current 4.8 lb/MMBtu SO₂ SIP limit if it were removed from the SIP, while still complying with the already SIP-approved Consent Agreement limit. In our analysis, we converted the Consent Agreement facility-wide lb/hr limit to a unit-level lb/MMBtu rate for multiple scenarios by dividing 40,837 lb/hr by the total heat input for all units assumed to be operating. An example of a scenario in which Labadie could potentially exceed the emission rate allowed under the 4.8 lb/MMBtu SO₂ limit but still comply with the Consent Agreement limit is when a single unit is operating at 100% load. A maximum hourly heat input rate of 6,107 MMBtu/hr (representative of either unit 3 or 4) is used in this example. Dividing 40,837 lb/hr by 6,107 MMBtu/hr equates to an SO₂ rate of 6.69 lb/MMBtu, which is greater than the 4.8 lb/MMBtu SO₂ limit in 10 CSR 10-6.260 in the current SIP. If this limit were removed from the SIP, there would not be a permanent and enforceable limit or condition in place to prevent Labadie from operating a single unit at an SO₂ rate higher than 4.8 lb/MMBtu.

In order for a state to use a previously SIP-approved measure (one that is already obtaining emissions reductions) as a substitute measure to satisfy the requirements of CAA section 110(l), the emissions reductions must be surplus, meaning they cannot otherwise be relied on for attainment/maintenance or Rate of Progress/Reasonable Further Progress requirements. The area should have an approved attainment/maintenance demonstration in order to ascertain that the emissions reductions from the existing SIP-approved measure are indeed surplus. As Missouri states in the TSD included in this docket, the purpose of the Consent Agreement was to strengthen the SIP related to attainment in the Jefferson County, Missouri nonattainment area for the 2010 1-hour SO₂ NAAQS. When the Jefferson County, Missouri area was redesignated to attainment for the 1-hour SO₂ NAAQS, the Consent Agreement was approved into the SIP as part of the maintenance plan for the area (87 FR 4508, January 28, 2022). The Labadie SO₂ emission limit in the Consent Agreement is not surplus and therefore cannot be relied on as a substitute measure to meet the requirements of section 110(l).

The EPA's approval of the removal of the 4.8 lbs/MMBtu SO₂ limit from the SIP would not be consistent with CAA section 110(l) because the substitute SO₂ limit from the already SIP-approved Consent Agreement is not as stringent as the SIP's 4.8 lb/MMBtu limit in all situations, nor is it surplus. Moreover, Missouri has not demonstrated that this change in the SIP would be protective of all NAAQS.

III. Have the requirements for approval of a SIP revision been met?

As explained above, because EPA's approval of the revision would not be consistent with CAA section 110(l), we are proposing to disapprove the submission. However, the state submission has met the public notice requirements for SIP submissions in accordance with 40 CFR 51.102. The submission also satisfied the completeness criteria of 40 CFR part 51, appendix V. The state provided public notice of the revisions from August 1, 2018, to October 4, 2018, and held a public hearing on September 27, 2018. The state received and addressed four comments from three entities, which included the EPA. The state did not make changes to the rule as a result of comments received prior to submitting to the EPA.

IV. What action is the EPA proposing to take?

The EPA is proposing to disapprove a SIP submission from Missouri that would rescind 10 CSR 10-6.260 “Restriction of Emission of Sulfur Compounds” and replace it with 10 CSR 10-6.261 “Control of Sulfur Dioxide Emissions.” By disapproving these revisions, 10 CSR 10-6.260 will be retained in the SIP, along with the already SIP-approved Consent Agreement. The EPA has determined that Missouri's proposed SIP revisions do not meet the requirements of the Clean Air Act because the revisions would remove permanent and enforceable emission limits, thereby relaxing the stringency of the SIP. Furthermore, Missouri has not shown that the proposed SIP revisions would not have an adverse impact on air quality.

Under section 179(a) of the CAA, final disapproval of a submittal that addresses a requirement of part D, title I of the CAA (CAA sections 171-193) or is required in response to a finding of substantial inadequacy as described in CAA section 110(k)(5) (SIP Call) starts a sanctions clock. The Missouri SIP submission that we propose to disapprove was not submitted to meet either of these requirements. Therefore, any action we take to finalize this proposed disapproval will not trigger mandatory sanctions under CAA section 179. In addition, CAA section 110(c)(1) provides that EPA must promulgate a Federal Implementation Plan (FIP) within two years after either finding that a State has failed to make a required submission or disapproving a SIP submission in whole or in part, unless EPA approves a SIP revision correcting the deficiencies within that two-year period. With respect to our proposed disapproval of Missouri's SIP submission, however, we propose to conclude that any FIP obligation resulting from finalization of the proposed disapproval would be satisfied by our determination that there is no deficiency in the SIP to correct. Specifically, the limits discussed in this proposed rulemaking would remain in the SIP and remain federally enforceable.

We are soliciting comments on this proposed action. Final rulemaking will occur after consideration of any comments.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

This action is not a significant regulatory action and was therefore not submitted to the Office of Management and Budget for review.

B. Paperwork Reduction Act (PRA)

This proposed action does not impose an information collection burden under the PRA because it does not contain any information collection activities.

C. Regulatory Flexibility Act (RFA)

I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. This action merely proposes to disapprove a SIP submission as not meeting the CAA.

D. Unfunded Mandates Reform Act (UMRA)

This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. The action imposes no enforceable duty on any state, local or tribal governments or the private sector.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

This action does not have tribal implications as specified in Executive Order 13175. This action does not apply on any Indian reservation land, any other area where the EPA or an Indian tribe has demonstrated that a tribe has jurisdiction, or non-reservation areas of Indian country. Thus, Executive Order 13175 does not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

The EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it merely proposes to disapprove a SIP submission as not meeting the CAA.

H. Executive Order 13211, Actions That Significantly Affect Energy Supply, Distribution or Use

This action is not subject to Executive Order 13211, because it is not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act

This rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low-Income Populations

The EPA believes the human health or environmental risk addressed by this action will not have potential disproportionately high and adverse human health or environmental effects on minority, low-income or indigenous populations. This action merely proposes to disapprove a SIP submission as not meeting the CAA.

List of Subjects in 40 CFR Part 52

• Environmental protection
• Air pollution control
• Incorporation by reference
• Intergovernmental relations
• Reporting and recordkeeping requirements
• Sulfur oxides