Proposed Rule2025-15460
Air Plan Approval; North Carolina; Revisions to Regulations for Sulfur Dioxide Emissions From Combustion Sources
Primary source
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Published
August 14, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve a State Implementation Plan (SIP) revision submitted by the North Carolina Division of Environmental Quality (NCDEQ), Division of Air Quality (DAQ) on November 28, 2023, for the purpose of revising regulations that establish sulfur dioxide (SO<INF>2</INF>) emission limits and compliance parameters for SO<INF>2</INF>-emitting combustion sources in the State. EPA is proposing to approve these changes pursuant to the Clean Air Act (CAA or Act) and EPA regulations.
Full Text
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<title>Federal Register, Volume 90 Issue 155 (Thursday, August 14, 2025)</title>
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[Federal Register Volume 90, Number 155 (Thursday, August 14, 2025)]
[Proposed Rules]
[Pages 39142-39144]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-15460]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R04-OAR-2024-0163; FRL-12823-01-R4]
Air Plan Approval; North Carolina; Revisions to Regulations for
Sulfur Dioxide Emissions From Combustion Sources
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve a State Implementation Plan (SIP) revision submitted by the
North Carolina Division of Environmental Quality (NCDEQ), Division of
Air Quality (DAQ) on November 28, 2023, for the purpose of revising
regulations that establish sulfur dioxide (SO<INF>2</INF>) emission
limits and compliance parameters for SO<INF>2</INF>-emitting combustion
sources in the State. EPA is proposing to approve these changes
pursuant to the Clean Air Act (CAA or Act) and EPA regulations.
DATES: Comments must be received on or before September 15, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R04-
OAR-2024-0163 at <a href="http://regulations.gov">regulations.gov</a>. Follow the online instructions for
submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. 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. 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 <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Matthew Bloemer, Multi-Air Pollutant
Coordination Section, Air Planning and Implementation Branch, Air and
Radiation Division, U.S. Environmental Protection Agency, Region 4, 61
Forsyth Street SW, Atlanta, Georgia 30303-8960. The telephone number is
(404) 562-9653. Mr. Bloemer can also be reached via electronic mail at
<a href="/cdn-cgi/l/email-protection#e3a18f8c868e8691cdae8297978b8694a3869382cd848c95"><span class="__cf_email__" data-cfemail="befcd2d1dbd3dbcc90f3dfcacad6dbc9fedbcedf90d9d1c8">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
I. Background
EPA is proposing to approve a SIP revision submitted by the NCDEQ,
on November 28, 2023, that revises Rule 15A North Carolina
Administrative Code (NCAC) 02D .0516, Sulfur Dioxide Emissions from
Combustible Sources. Rule 02D .0516 requires sources emitting
SO<INF>2</INF> through combustion and discharging through a vent,
stack, or chimney to comply with an emission standard of 2.3 pounds per
million British thermal unit (lbs/MMBtu). The Rule also provides
criteria for how affected sources should determine compliance with the
emission standard. North Carolina's November 28, 2023, SIP revision
seeks to modify the Rule 02D .0516 applicability criteria respecting
control devices and the provisions for determining compliance with the
SO<INF>2</INF> emission standard. More specifically, the SIP revision
seeks to provide clarity and consistency with North Carolina's position
that the use of supplemental fuels in combustion units beyond what is
needed for proper operation is not a means for compliance with the
SO<INF>2</INF> emission standard at Rule 02D .0516.
SO<INF>2</INF> is one of the group of gases called sulfur oxides
(SO<INF>X</INF>). EPA's SO<INF>2</INF> national ambient air quality
standards (NAAQS) \1\ are designed to protect against exposure to the
entire group of SO<INF>X</INF>. Thus, control measures that reduce
SO<INF>2</INF> emissions can generally be expected to reduce exposure
to all gaseous SO<INF>X</INF>. Emissions of SO<INF>2</INF> are mostly
generated through the combustion of fuel or waste that contain sulfur.
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\1\ The primary SO<INF>2</INF> NAAQS is 75 parts per billion
(ppb) (measured as the 99th percentile of 1-hour daily maximum
concentrations, averaged over 3 years). See 40 CFR 50.17. Short-term
exposures to SO<INF>2</INF> can harm the respiratory system and make
breathing difficult. People with asthma, particularly children, are
sensitive to these effects of SO<INF>2</INF>. At high
concentrations, gaseous SO<INF>X</INF> can harm trees and plants by
damaging foliage and decreasing growth.
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North Carolina's November 28, 2023, SIP revision was developed in
response
[[Page 39143]]
to a declaratory ruling \2\ issued by the State's Environmental
Management Commission (EMC) that the plain language of Rule 02D .0516
does not prohibit the use of supplemental fuels, including natural gas,
to determine compliance with the 2.3 lbs/MMBtu SO<INF>2</INF> emission
standard. As a result, NCDEQ revised Rule 02D .0516 to align with its
position that sources cannot demonstrate compliance with the
SO<INF>2</INF> emission standard by burning excess supplemental fuel
beyond what is necessary for proper operation of a combustion unit.
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\2\ North Carolina's declaratory rulings are authorized by the
State's Administrative Procedure Act pursuant to N.C. Gen. Stat.
Sec. 150B-4. Using this process, an individual aggrieved may
request that an agency, in relevant part, ``issue a declaratory
ruling as to the validity of a rule or as to the applicability to a
given state of facts of a statute administered by the agency or of a
rule or order of the agency.'' N.C. Gen. Stat. Sec. 150B-4(a). As
set forth in N.C. Gen. Stat. Sec. 150B-4(a), a declaratory ruling
must fall into one of three categories: (1) a request regarding the
validity of a rule, (2) a request regarding the application of a
statute, rule, or order within the agency's purview ``to a given
state of facts,'' or (3) a request to resolve inconsistent
interpretations of the agency's rules. See North Carolina's November
28, 2023, SIP revision in the docket.
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II. North Carolina's SIP Revision and EPA's Analysis
North Carolina's SIP revision modifies and reformats Rule 02D .0516
such that paragraph (a) is split into two separate paragraphs, (a) and
(b); renumbers existing paragraph 02D .0516(b) to new paragraph 02D
.0516(c); and includes minor grammatical and rewording edits for
clarity. Changes to paragraph 02D .0516(a) include the addition of the
phrase ``air pollution control devices'' and the term ``flare'' as well
as minor grammatical edits due to these additions. These amendments
clarify that any source of combustion includes air pollution control
devices and that the rule applies to subject emissions discharged
through a flare as well as a chimney, vent, or stack.
The compliance language at paragraph 02D. 0516(a) in the SIP
states, ``Sulfur dioxide formed by the combustion of sulfur in fuels,
wastes, ores and other substances shall be included when determining
compliance with this standard. Sulfur dioxide formed or reduced as a
result of treating flue gases with sulfur trioxide or other materials
shall also be accounted for when determining compliance with this
standard.'' This language is moved to paragraph 02D. 0516(b) as
subparagraphs (b)(1)1 and (b)(1)2. The criteria at subparagraph (b)(1)
is further amended by removing the phrase ``included when determining
compliance with this standard.'' This language is repurposed as the
introduction of paragraph (b), ``When determining compliance with this
standard'' (i.e., the SO<INF>2</INF> emission standard at paragraph
02D. 0516(a)). The criteria at paragraph (b)(2) is revised by replacing
the phrase ``also be accounted for when determining compliance with
this standard'' with the phrase ``be included in the computation of
emissions.'' This amendment clarifies the discharge or reduction of
SO<INF>2</INF> through the stated process shall be included in the
computation of emissions to determine compliance with the
SO<INF>2</INF> emission standard.
The SIP revision also adds the following new compliance requirement
at paragraph 02D. 0516(b)(3): ``the determination of Btu input shall
not include the contribution from any portion of fuels used exclusively
to inflate the heat input value used to demonstrate compliance with the
emission standard in Paragraph (a) of this Rule.'' The addition of
paragraph (b)(3) provides that the computation of emissions to
determine compliance with the emission standard shall not include
SO<INF>2</INF> emissions from the use of excess supplemental fuel
beyond what is necessary to operate a combustion unit. The revisions to
paragraph (b)(3) provide clarity and consistency with the State's
position that the use of supplemental fuel beyond what is needed for
proper operation of a combustion unit is not a means for determining
compliance with the 2.3 lbs/MMBtu SO<INF>2</INF> emission limit.
Former paragraph 02D. 0516(b) is renumbered to paragraph 02D.
0516(c) with no modifications to the original language. Lastly, DAQ's
SIP revision also makes non-substantive grammatical or typographical
changes because of modifications to Rule 02D .0516. DAQ's revisions to
Rule 15A NCAC 02D .0516 became state-effective on June 1, 2023.
For the reasons discussed above, these proposed changes will not
interfere with any applicable requirement concerning attainment and
reasonable further progress, or any other applicable requirement of the
Act. Therefore, EPA is proposing to approve North Carolina's November
28, 2023, SIP revision.
III. Incorporation by Reference
In this document, 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, and as discussed in Sections I and II
of this preamble, EPA is proposing to incorporate by reference North
Carolina Rule 15A NCAC 02D .0516, Sulfur Dioxide Emissions from
Combustible Sources, effective June 1, 2023, which clarifies that
sources cannot demonstrate compliance with the SO<INF>2</INF> emission
standard in the rule by burning excess supplemental fuel beyond what is
necessary for proper operation of the combustion unit. EPA has made,
and will continue to make, these materials generally available through
<a href="http://www.regulations.gov">www.regulations.gov</a> and at the EPA Region 4 office (please contact the
person identified in the ``For Further Information Contact'' section of
this preamble for more information).
IV. Proposed Action
EPA is proposing to approve North Carolina's November 28, 2023, SIP
revision at Rule 15A NCAC 02D .0516 to provide clarity and consistency
with the State's position that the use of supplemental fuels in
combustion units beyond what is needed for proper operation is not a
means for compliance with the 2.3 lbs/MMBtu SO<INF>2</INF> emission
standard at Rule 02D .0516.
V. 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. See 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
proposed action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this proposed action:
<bullet> 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);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
[[Page 39144]]
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> 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).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Nitrogen
dioxide, Reporting and recordkeeping requirements, Sulfur oxides.
(Authority: 42 U.S.C. 7401 et seq.)
Dated: August 6, 2025.
Kevin McOmber,
Regional Administrator, Region 4.
[FR Doc. 2025-15460 Filed 8-13-25; 8:45 am]
BILLING CODE 6560-50-P
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