# 91 FR 23046: Air Plan Approval; Maryland; Reasonably Available Control Technology for Municipal Waste Combustors

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-08364

## Section

- **Citation:** 91 FR 23046
- **Heading:** Air Plan Approval; Maryland; Reasonably Available Control Technology for Municipal Waste Combustors
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 91 / 91 FR 23046

## Text

1 MWC means an incinerator that burns only municipal solid waste. A large MWC is an existing municipal waste combustor that has a capacity greater than 250 tons per day. Code of Maryland Regulations (COMAR) 26.11.08.01.
In this proposed rulemaking, regarding MDE's SIP revision #18-04, the EPA is only proposing approval on the statewide RACT control regulations and definitions that relate to MWCs. SIP revision #18-04 contains additional elements, including Maryland's certification that the State satisfied all required statewide RACT elements for the 2008 ozone NAAQS. The EPA is not proposing to act on those other elements, including the certification, that comprise the remainder of MDE's SIP revision #18-04. The EPA will take separate action on those other portions of the July 27, 2018 SIP submittal at another time. The EPA is proposing to approve all portions of MDE's SIP revision #20-10, submitted to the EPA on July 17, 2020.
I. Background
A. Ozone NAAQS and RACT Requirements
The CAA requires states to address emissions of NO X and volatile organic compound(s) (VOC) from certain sources in certain parts of the country to prevent photochemical reactions that result in ozone formation. RACT is an important strategy for reducing NO X and VOC emissions from major stationary sources. For purposes of implementing the ozone NAAQS, a “major source” is defined based on the source's potential to emit (PTE) NO X , VOC, or both pollutants. See CAA sections 182, 184, and 302. The applicable thresholds differ based on the classification of the nonattainment area in which the source is located. See CAA section 182.
Areas designated nonattainment for the ozone NAAQS are subject to the general nonattainment area planning requirements of CAA section 172. 2 Section 172(c)(1) of the CAA provides that SIPs for nonattainment areas must include reasonably available control measures (RACM), including emissions reductions from existing sources through adoption of RACT
Guidance for Determining Acceptability of SIP Regulations in Non-Attainment Areas.” See also 44 FR 53761, 53762 (September 17, 1979).
Section 184(a) of the CAA established the Ozone Transport Region (OTR) comprised of all or portions of 12 eastern states, including all of Maryland. Section 184(b)(1)(B) of the CAA requires RACT to be implemented on all sources in the OTR that are covered by a CTG. Further, CAA section 184(b)(2) requires that any source in the OTR with a PTE of at least 50 tons per year (tpy) of VOC “be considered a major stationary source and subject to the requirements which would be applicable to major stationary sources if the area were classified as a Moderate nonattainment area.” As such, RACT applies to all sources of VOC in the OTR with a PTE of at least 50 tpy.
B. Applicability of RACT Requirements in Maryland
Maryland previously has been subject to the RACT requirements stemming from both ozone nonattainment area planning requirements and because of its' location in the OTR. For both the

1979 1-hour ozone NAAQS and the 1997 8-hour ozone NAAQS, the Baltimore nonattainment area (which includes Anne Arundel, Baltimore, Carroll, Harford, and Howard Counties of Maryland, as well as Baltimore City, Maryland), the Washington DC nonattainment area (which includes Calvert, Charles, Frederick, Montgomery, and Prince George's Counties of Maryland), and the Philadelphia nonattainment area (which includes Cecil County, Maryland) were designated as Moderate or higher. 4 The remaining Maryland counties were still subject to RACT requirements because they are in the OTR. Since the early 1990s, Maryland implemented numerous RACT controls throughout the State to meet RACT requirements under the 1979 1-hour and the 1997 8-hour ozone standards. Maryland revised and promulgated its RACT regulations and demonstrated that it complied with the 1997 RACT requirements in a SIP revision approved by the EPA on July 13, 2012 (77 FR 41278)
uirements because they are in the OTR. Since the early 1990s, Maryland implemented numerous RACT controls throughout the State to meet RACT requirements under the 1979 1-hour and the 1997 8-hour ozone standards. Maryland revised and promulgated its RACT regulations and demonstrated that it complied with the 1997 RACT requirements in a SIP revision approved by the EPA on July 13, 2012 (77 FR 41278).
4 Additionally, Kent and Queen Anne's Counties in Maryland were designated as Marginal nonattainment and therefore were not subject to RACT requirements due to their nonattainment status.
Under CAA section 109(d), the EPA is required to periodically 5 review and promulgate, as necessary, revisions to the NAAQS to continue to protect human health and the environment. On March 27, 2008 (73 FR 16436), the EPA revised the 8-hour ozone standard to 0.075 parts per million (ppm). On May 21, 2012 (77 FR 30088), the EPA finalized designations for the 2008 ozone NAAQS, designating as nonattainment three areas that contain portions of Maryland, including the Baltimore Moderate nonattainment area, the Washington, DC Marginal nonattainment area, and the Philadelphia Marginal nonattainment area. Although the remaining Maryland counties were designated as unclassifiable/attainment for the 2008 ozone NAAQS, they are still part of the OTR and are still required to address RACT requirements.
5 The CAA requires the Administrator to complete a review, making revisions as appropriate, “at five-year intervals” and also authorizes review and revision, as appropriate, “more frequently.”
On October 26, 2015 (80 FR 65292), the EPA revised the 8-hour ozone standard to 0.070 ppm. The EPA finalized the designations for the 2015 ozone NAAQS on June 4, 2018 (83 FR 25776), designating as nonattainment the Baltimore area, the Washington DC area, and the Philadelphia area as Marginal
ate, “at five-year intervals” and also authorizes review and revision, as appropriate, “more frequently.”
On October 26, 2015 (80 FR 65292), the EPA revised the 8-hour ozone standard to 0.070 ppm. The EPA finalized the designations for the 2015 ozone NAAQS on June 4, 2018 (83 FR 25776), designating as nonattainment the Baltimore area, the Washington DC area, and the Philadelphia area as Marginal. Later, the Washington DC area 6 was reclassified to Moderate and both the Baltimore area 7 and the Philadelphia area 8 were reclassified to Moderate, and then to Serious. As with the previous NAAQS and in accordance with CAA section 184(b), the Maryland counties that were designated as attainment/unclassifiable for the 2015 NAAQS are still required to address RACT requirements as they are part of the OTR. Therefore, the entire State of Maryland was required to submit to the EPA SIP revisions that demonstrated how it meets RACT requirements under the 2008 and 2015 ozone NAAQS, including for major stationary sources of NO X located within the State boundaries. Maryland retained its major source thresholds at 25 tpy for VOC and NOx sources in the Baltimore, Washington, DC, and Philadelphia Severe 1-hour ozone nonattainment areas. The State also retained its major source thresholds at 50 tpy for VOC and 100 tpy for NO X in all remaining Maryland counties, consistent with the CAA requirements for states in the OTR.
6 87 FR 60897 (October 7, 2022).
7 See 87 FR 60897 (October 7, 2022) and 89 FR 62663 (August 1, 2024).
8 See 87 FR 60897 (October 7, 2022) and 89 FR 61025 (July 30, 2024).
C. The EPA Guidance and Requirements
The EPA affirmed RACT requirements through final implementation rules for each ozone NAAQS, as well as through guidance. On March 6, 2015 (80 FR 12264), the EPA issued its final rule for implementing the 2008 ozone NAAQS (the 2008 ozone SIP requirements rule 9 )
RACT requirements through final implementation rules for each ozone NAAQS, as well as through guidance. On March 6, 2015 (80 FR 12264), the EPA issued its final rule for implementing the 2008 ozone NAAQS (the 2008 ozone SIP requirements rule 9 ). This rule addressed, among other things, control and planning obligations as they apply to nonattainment areas under the 2008 ozone NAAQS, including RACT. In this rule, the EPA specified that states can meet the RACT requirements through the adoption of new or more stringent regulations or controls that represent RACT control levels or through certification that previously adopted RACT controls in their SIP revisions approved by the EPA under a prior ozone NAAQS continue to represent adequate RACT control levels for attainment of the 2008 ozone NAAQS. 10 All RACT SIP submittals, including certifications, must be accompanied by appropriate supporting information such as consideration of information received during the public comment period and consideration of new data, if any. Adoption of new RACT regulations can occur when states have new stationary sources not covered by existing RACT regulations, or when new data or technical information indicates that a previously adopted RACT measure does not represent a newly available RACT control level. On December 6, 2018, the EPA published a final implementation rule that outlined the obligations that states in the OTR and states with ozone nonattainment areas needed to address for the 2015 ozone NAAQS (the 2015 ozone SIP requirements rule 11 ), which included retaining general RACT requirements codified for the 2008 ozone NAAQS at 40 Code of Federal Regulations (CFR) 51.1112.
9 The 2008 implementation rule is codified at 40 CFR part 51 subpart AA. See also 80 FR 12279 (March 6, 2015).
10 See 80 FR 12264 at 12279 (March 6, 2015).
11 The 2015 SIP requirements rule is codified at 40 CFR part 51 subpart CC. See also 83 FR 62998 (December 6, 2018).
II
taining general RACT requirements codified for the 2008 ozone NAAQS at 40 Code of Federal Regulations (CFR) 51.1112.
9 The 2008 implementation rule is codified at 40 CFR part 51 subpart AA. See also 80 FR 12279 (March 6, 2015).
10 See 80 FR 12264 at 12279 (March 6, 2015).
11 The 2015 SIP requirements rule is codified at 40 CFR part 51 subpart CC. See also 83 FR 62998 (December 6, 2018).
II. Summary of Maryland's SIP Revisions
On July 27, 2018, the EPA received MDE SIP revision #18-04 which included, among other things, MWC NO X emission limits of 205 parts per million volume (ppmv) 24-hour average. 12 These MWC NO X emission limits were strengthened in MDE's July 17, 2020 SIP revision #20-10. However, at least a portion of the proposed changes included in SIP revision #18-04 provide regulatory elements that are relied upon by SIP revision #20-10. Therefore, some components of the SIP revision #18-04 need to be approved along with all of SIP revision #20-10 in order to incorporate the most up to date MWC RACT limits into the SIP.
12 Moreover, the SIP submission includes a requirement that a person may not operate a municipal waste combustor that has a burning capacity of 35 tons or more per day and less than or equal to 250 tons per day that was constructed on or before August 30, 1999, which results in violation of the provisions of 40 CFR part 62 subpart JJJ.
The following definitions from SIP revision #18-04 are being proposed for approval in this action in order to support the proposed approval of SIP revision #20-10: “Continuous emission monitoring,” “Existing municipal waste combustor (existing MWC),” “Incinerator,” “Incinerator operator,” “Malfunction,” “Municipal Solid Waste,” “Municipal waste combustor (MWC),” “Operating day,” “Shutdown,” and “Startup.” Additionally, revisions to sections 26.11.08.02 (Applicability) and 26.11.08.07 (Requirements for Municipal Waste Combustors) in SIP #18-04 are incorporated into this action
on monitoring,” “Existing municipal waste combustor (existing MWC),” “Incinerator,” “Incinerator operator,” “Malfunction,” “Municipal Solid Waste,” “Municipal waste combustor (MWC),” “Operating day,” “Shutdown,” and “Startup.” Additionally, revisions to sections 26.11.08.02 (Applicability) and 26.11.08.07 (Requirements for Municipal Waste Combustors) in SIP #18-04 are incorporated into this action. 13 Although MDE's SIP revision #18-04 includes other requests for EPA action, this action only proposes to take action on, and proposes to approve, the X RACT requirements for MWCs. 14
13 Note that both sections were subsequently updated through SIP revision #20-10.
14 The EPA will take separate action on all other areas of the July 27, 2018 SIP submission.
SIP revision #20-10 incorporates two rounds of regulatory revisions. The first action, which Maryland adopted on December 6, 2018, repealed the then-existing State NO X RACT regulations codified at COMAR 26.11.09.08H and also promulgated new NO X RACT emission limits for large MWCs at COMAR 26.11.08.10. 15 This new regulation, COMAR 26.11.08.10, adopted by Maryland in December 2018, requires that the State's two large MWCs 16 meet specific 24-hour block average emission rates by May 1, 2019, and NO X 30-day rolling average emission rates by May 1, 2020, except during periods of startup and shutdown.
15 This original State revision also amended opacity requirements under 26.11.01, added definitions, repealed 26.11.08.08-l and updated references to 26.11.08.08-2, which was the current emission standards and requirements for Hospital, Medical, and Infectious Waste Incinerators (HMIWIs).
16 The Montgomery County Resource Recovery Facility and the Wheelabrator Baltimore, Inc.
6.11.09.08H and also promulgated new NO X RACT emission limits for large MWCs at COMAR 26.11.08.10. 15 This new regulation, COMAR 26.11.08.10, adopted by Maryland in December 2018, requires that the State's two large MWCs 16 meet specific 24-hour block average emission rates by May 1, 2019, and NO X 30-day rolling average emission rates by May 1, 2020, except during periods of startup and shutdown.
15 This original State revision also amended opacity requirements under 26.11.01, added definitions, repealed 26.11.08.08-l and updated references to 26.11.08.08-2, which was the current emission standards and requirements for Hospital, Medical, and Infectious Waste Incinerators (HMIWIs).
16 The Montgomery County Resource Recovery Facility and the Wheelabrator Baltimore, Inc..
At the time, the EPA's 2015 SSM policy 17 required that emission limits be in place at all times, even during startup and shutdown periods, and so in Maryland's second state-level action, MDE made revisions to ensure that during all hours of large MWC operation, there was an applicable NO X emission standard in place. This second action was adopted by the State of Maryland on May 4, 2020.
17 The EPA's 2015 SSM SIP Policy; Findings of Substantial Inadequacy; and SIP Calls to Amend Provisions Applying to Excess Emissions During Periods of Startup, Shutdown and Malfunction, (80 FR 33839, June 12, 2015).
Overall, the SIP changes proposed through the MWC portion of SIP revision #18-04 and SIP revision #20-10 establish the following:
• Small MWCs, those with a capacity of at least 35 tons and less than or equal to 250 tons per day, that were constructed on or before August 30, 1999 shall not be in violation of the provisions of 40 CFR part 62 subpart JJJ. 18
18 Includes requirements to install and operate continuous emission monitoring for NO X and emissions limits according to combustion technology ( See table 3 of subpart JJJ)
actions taken during periods of startup and shutdown in signed, contemporaneous operating logs.
III. The EPA's Evaluation of the Submittals
MDE's revisions to their state MWC regulations were made through three separate state-level revisions which were submitted to the EPA through two SIP submittals, one on July 27, 2018 (SIP revision #18-04), and another on July 17, 2020 (SIP revision #20-10). In addition to revising the NO X emission limits for MWCs in Maryland and setting these limits as RACT, the July 17, 2020, SIP submission also addresses previous aspects of the regulation that allowed for non-continuous limits during startup and shutdown, in accordance with the EPA's 2015 SSM Policy. Overall, encompassing all three revisions submitted by MDE to the EPA, the State is requesting to adopt into its SIP, NO X emission limits for large MWCs as well as additional NO X emission rates for MWCs in warm-up mode so that all operating hours have a NO X standard in place. 19
19 Maryland is also requesting to adopt into its SIP the requirements for small MWCS under COMAR 26.11.08.07.
The amendments to COMAR 26.11.08.10 contain regulations that required Wheelabrator to meet a NO X 24-hour block average emission rate of 150 ppmv and for MCRR to meet a NO X 24-hour block average emission rate of 140 ppmv. The NO X 24-hour block average emission rate of 150 ppmv is consistent with RACT rates in Connecticut, New Jersey, New York, and Massachusetts. Table 1, in this document provides a look at the NO X limits MWCs in certain OTR states. Additionally, to further ensure consistent long-term operation of NO X control technologies, Maryland required the large MWCs to meet new, individual NO X 30-day rolling average emission rates by May 1, 2020. 20
20 Wheelabrator's NO X 30-day rolling average emission rate is 145 ppmv and MCRR's is 105 ppmv
s that required Wheelabrator to meet a NO X 24-hour block average emission rate of 150 ppmv and for MCRR to meet a NO X 24-hour block average emission rate of 140 ppmv. The NO X 24-hour block average emission rate of 150 ppmv is consistent with RACT rates in Connecticut, New Jersey, New York, and Massachusetts. Table 1, in this document provides a look at the NO X limits MWCs in certain OTR states. Additionally, to further ensure consistent long-term operation of NO X control technologies, Maryland required the large MWCs to meet new, individual NO X 30-day rolling average emission rates by May 1, 2020. 20
20 Wheelabrator's NO X 30-day rolling average emission rate is 145 ppmv and MCRR's is 105 ppmv.
Table 1—State NO X Limits for Municipal Waste Combustors State NO X limits ppmvd at 7% oxygen Averaging period Rule citation Connecticut 146 (processed-municipal solid waste combustor) 24-hour average 22a-174-38 (SIP approved for the 2008 and 2015 ozone NAAQS, 87 FR 38284, June 28, 2022). 150 (mass burn waterfall combustor). 177 (mass burn refractory combustor). New Jersey 150 calendar day N.J.A.C. 7:27-19.12 (SIP approved for the 2008 ozone NAAQS, 83 FR 50506, October 9, 2018). New York 150 (mass burn waterfall) 170 (rotary combustor). 24-hour average 219-10.2 (SIP approved for the 2008 and 2015 ozone NAAQS, 88 FR 77208, November 9, 2024). 150 (mass burn waterfall). annual 150 (rotary combustor). Massachusetts 150 (mass burn waterfall) 146 (refuse-derived fuel stoker). 24-hour average 310 CMR 7.08 (SIP approved for the 2008 and 2015 ozone NAAQS, 85 FR 65236, October 15, 2020). Maryland's third revision to the State's MWC regulation created a mass-based emission limit for warm-up periods, which ends when startup begins. 21 22 For further details regarding the analysis and changes Maryland completed to the startup, shutdown, and warm-up periods of the large MWC regulation, refer to the technical support document (TSD) that accompanies this proposed rulemaking
nts of 1 CFR 51.5, the EPA is proposing to incorporate by reference the COMAR regulations described in section II of this document. The EPA made, and will continue to make, these materials generally available through www.regulations.gov and at the EPA Region III Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).
VII. Statutory and Executive Order Reviews
Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. 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 Order 12866 (58 FR 51735, October 4, 1993);
• Is not an Executive Order 14192 (90 FR 9065, February 6, 2025) regulatory action because this action is not significant under Executive Order 12866;
• 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

## Nearby sections

- [91 FR 205 Airworthiness Directives; General Atomics AeroTec Systems GmbH (Type Certificate Previously Held by RUAG Aerospace Services GmbH) Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2025-24233.md)
- [91 FR 457 Airworthiness Directives; Gulfstream Aerospace LP Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00119.md)
- [91 FR 633 Special Conditions: ZeroAvia, Inc. Model ZA601 Electric Engines](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00171.md)
- [91 FR 654 Clean Air Act Title V Operating Permit Program Revision; District of Columbia](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00215.md)
- [91 FR 937 Air Plan Approval; Ohio; Ohio Permit Rules Revisions](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00258.md)
- [91 FR 1098 National Bank Chartering](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00372.md)
- [91 FR 1104 Airworthiness Directives; The Boeing Company Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00409.md)
- [91 FR 1257 Fisheries of the Northeastern United States; Amendment 25 (Revised) to the Northeast Multispecies Fishery Management Plan; Atlantic Cod Stocks in Need of Conservation and Management](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00498.md)
- [91 FR 1464 National Bank Chartering; Correction](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00603.md)
- [91 FR 1471 Corporate Credit Unions](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00595.md)
- [91 FR 1473 Amendment of Class D Airspace and Establishment of Class E Airspace; Fort Worth, TX](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00604.md)
- [91 FR 1494 The Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule III for Model Years 2022 to 2031 Passenger Cars and Light Trucks](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00537.md)
- [91 FR 1724 Removing Redundant, Obsolete, and Inefficient Provisions From the Regulations Governing Restrictions on Lobbying](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00687.md)
- [91 FR 1724 Mitigation Methods for Launch Vehicle Upper Stages on the Creation of Orbital Debris; Withdrawal](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-00680.md)

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2026-08364. Check the current official text before relying on it. Not legal advice.