Air Plan Approval; South Carolina; Second Planning Period Regional Haze Plan

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R04-OAR-2022-0367; FRL-10406-01-R4]</DEPDOC> <SUBJECT>Air Plan Approval; South Carolina; Second Planning Period Regional Haze Plan</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve a regional haze State Implementation Plan (SIP) revision submitted by the South Carolina Department of Health and Environmental Control (DHEC) dated March 3, 2022, as satisfying the applicable requirements under the Clean Air Act (CAA or Act) and EPA's Regional Haze Rule (RHR) for the program's second planning period. South Carolina's SIP submission addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress toward the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second planning period of the regional haze program. EPA is proposing this action pursuant to sections 110 and 169A of the Act. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before September 29, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R04-OAR-2022-0367, at <E T="03">https://www.regulations.gov.</E> Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov.</E> 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 ( <E T="03">i.e.,</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 <E T="03">http://www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> 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. Mr. Bloemer can be reached via telephone at (404) 562-9653 or electronic mail at <E T="03">Bloemer.Matthew@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. What action is EPA proposing?</FP> <FP SOURCE="FP-2">II. Background and Requirements for Regional Haze Plans</FP> <FP SOURCE="FP1-2">A. Regional Haze Background</FP> <FP SOURCE="FP1-2">B. Roles of Agencies in Addressing Regional Haze</FP> <FP SOURCE="FP-2">III. Requirements for Regional Haze Plans for the Second Planning Period</FP> <FP SOURCE="FP1-2">A. Long-Term Strategy (LTS) for Regional Haze</FP> <FP SOURCE="FP1-2">B. Reasonable Progress Goals (RPGs)</FP> <FP SOURCE="FP1-2">C. Monitoring Strategy and Other State Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">D. Requirements for Periodic Reports Describing Progress Towards the RPGs</FP> <FP SOURCE="FP1-2">E. Requirements for State and Federal Land Manager (FLM) Coordination</FP> <FP SOURCE="FP-2">IV. EPA's Evaluation of South Carolina's Regional Haze Submission for the Second Planning Period</FP> <FP SOURCE="FP1-2">A. Identification of Class I Areas</FP> <FP SOURCE="FP1-2">B. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the URP</FP> <FP SOURCE="FP1-2">C. LTS for Regional Haze</FP> <FP SOURCE="FP1-2">D. RPGs</FP> <FP SOURCE="FP1-2">E. Monitoring Strategy and Other Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">F. Requirements for Periodic Reports Describing Progress Toward the RPGs</FP> <FP SOURCE="FP1-2">G. Requirements for State and FLM Coordination</FP> <FP SOURCE="FP-2">V. Proposed Action</FP> <FP SOURCE="FP-2">VI. Statutory and Executive Order Reviews </FP> </EXTRACT> <HD SOURCE="HD1">I. What action is EPA proposing?</HD> On March 3, 2022, South Carolina DHEC  <SU>1</SU> <FTREF/> submitted a revision to its SIP to address regional haze for the second planning period (Haze Plan). South Carolina DHEC made the SIP submission to satisfy the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. EPA is proposing to approve South Carolina's Haze Plan as satisfying applicable statutory and regulatory requirements. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  On July 1, 2024, DHEC was restructured into a health agency, the Department of Public Health, and an environmental agency, the Department of Environmental Services (DES). In a letter dated June 20, 2024, South Carolina represented to EPA that all the functions, powers, and duties of the environmental divisions, offices, and programs of DHEC, including the authority to administer and enforce state implementation plans, are retained and continued in full force and effect under DES. The letter is in the docket for this proposed rulemaking. The state agency will simply be referred to as the State or South Carolina for the remainder of this document. </FTNT> <FTNT> <SU>2</SU>  In a letter dated August 15, 2022, EPA found that South Carolina's Haze Plan meets the completeness criteria outlined in 40 CFR part 51, Appendix V. A completeness determination does not constitute a finding on the merits of the submission or whether it meets the relevant criteria for SIP approval. The August 15, 2022, letter is included in the docket for this rulemaking. </FTNT> <HD SOURCE="HD1">II. Background and Requirements for Regional Haze Plans</HD> A detailed history and background of the regional haze program is provided in prior EPA proposal actions. <SU>3</SU> <FTREF/> For additional background on the 2017 RHR revisions, please refer to Section III. Overview of Visibility Protection Statutory Authority, Regulation, and Implementation of “Protection of Visibility: Amendments to Requirements for State Plans” of the 2017 RHR. <SU>4</SU> <FTREF/> The following is an abbreviated history and background of the regional haze program and 2017 RHR as it applies to the current proposed action. <FTNT> <SU>3</SU>   <E T="03">See</E> 90 FR 13516 (March 24, 2025). </FTNT> <FTNT> <SU>4</SU>   <E T="03">See</E> 82 FR 3078 (January 10, 2017), located at <E T="03">www.federalregister.gov/documents/2017/01/10/2017-00268/protection-of-visibility-amendments-to-requirements-for-State-plans#h-16.</E> </FTNT> <HD SOURCE="HD2">A. Regional Haze Background</HD> In the 1977 CAA Amendments, Congress created a program for protecting visibility in the nation's mandatory Class I Federal areas, which include certain national parks and wilderness areas. <SU>5</SU> <FTREF/> <E T="03">See</E> CAA section 169A. The CAA establishes as a national goal the “prevention of any future, and the remedying of any existing, impairment of visibility in mandatory Class I Federal areas which impairment results from manmade air pollution.” <E T="03">See</E> CAA section 169A(a)(1). <FTNT> <SU>5</SU>  Areas statutorily designated as mandatory Class I Federal areas consist of national parks exceeding 6,000 acres, wilderness areas and national memorial parks exceeding 5,000 acres, and all international parks that were in existence on August 7, 1977. <E T="03">See</E> CAA section 162(a). There are 156 mandatory Class I areas. The list of areas to which the requirements of the visibility protection program apply is in 40 CFR part 81, subpart D. </FTNT> Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities which are located across a broad geographic area and that emit pollutants that impair visibility. Visibility impairing pollutants include fine and coarse particulate matter (PM) ( <E T="03">e.g.,</E> sulfates, nitrates, organic carbon, elemental carbon, and soil dust) and their precursors ( <E T="03">e.g.,</E> sulfur dioxide (SO <E T="52">2</E> ), nitrogen oxides (NO <E T="52">X</E> ), and, in some cases, volatile organic compounds (VOC) and ammonia (NH <E T="52">3</E> )). Fine particle precursors react in the atmosphere to form fine particulate matter (particles less than or equal to 2.5 micrometers (μm) in diameter, PM <E T="52">2.5</E> ), which impairs visibility by scattering and absorbing light. Visibility impairment reduces the perception of clarity and color, as well as visible distance. <SU>6</SU> <FTREF/> <FTNT> <SU>6</SU>  There are several ways to measure the amount of visibility impairment, <E T="03">i.e.,</E> haze. One such measurement is the deciview, which is the principal metric defined and used by the RHR. Under many circumstances, a change in one deciview will be perceived by the human eye to be the same on both clear and hazy days. The deciview is unitless. It is proportional to the logarithm of the atmospheric extinction of light, which is the perceived dimming of light due to its being scattered and absorbed as it passes through the atmosphere. Atmospheric light extinction (b <SU>ext</SU> ) is a metric used for expressing visibility and is measured ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 146k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━