Comments on Proposed Air Plan Approval for South Dakota’s Regional Haze Plan — Second Implementation Period

Joe Stein
Air and Radiation Division
Region 8
U.S. Environmental Protection Agency
1595 Wynkoop St.
Denver, CO 80202

Electronic Filing Regulations.gov

Re: Comments on Proposed Air Plan Approval; South Dakota; Regional Haze Plan for the Second Implementation Period [EPA Docket No. EPA–R08–OAR–2024–0609]

Dear Mr. Stein,

The National Parks Conservation Association (NPCA), Sierra Club and the Coalition to Protect America’s National Parks (collectively, Conservation Groups) submit the following comments on the Environmental Protection Agency’s (EPA or Agency) proposal to approve South Dakota’s Regional Haze State Implementation Plan (SIP) for the Second Planning Period (SIP Revision), 90 Fed. Reg. 20,425 (proposed May 14, 2025). The Conservation Groups submitted public comments to South Dakota’s Department of Agriculture & Natural Resources (DANR) on the State’s draft SIP Revision on April 20, 2022, raising a number of issues with that draft SIP Revision; those comments are attached and incorporated by reference.¹Nat’l Parks Conservation Ass’n, et al., Conservation Organizations’ Comments on South Dakota’s Proposed Regional Haze State Implementation Plan for the Second Planning Period (Apr. 20, 2022) [hereinafter “Conservation Orgs State Comments”] (attached as Ex. 1).

The Conservation Groups are active nationwide in advocating for strong air quality requirements to protect our national parks and wilderness areas. These groups have long participated in Regional Haze SIP comment periods, rulemakings and litigation across the country to ensure that states and EPA satisfy their obligations under the Clean Air Act (CAA or Act) and the Regional Haze Rule (RHR). The Conservation Groups’ members who live in South Dakota—including NPCA’s over 4,000 members, Sierra Club’s 1,122 members and the Coalition’s 13 current members and many others who have lived and/or worked in South Dakota throughout their careers with the National Park Service—use and enjoy regional Class I areas that are impacted by South Dakota’s sources of haze-forming pollution.

EPA’s proposal relies on the new policy that the Agency recently announced in its proposal to approve West Virginia’s Regional Haze SIP to justify approving South Dakota’s SIP Revision despite the fact that the State does not require any sources to adopt emission reduction measures.²90 Fed. Reg. 20,434. In comments submitted to EPA Region 3 on its West Virginia proposal, the Conservation Groups extensively addressed EPA’s new policy.³Nat’l Parks Conservation Ass’n, et al., Comments on Proposed Air Plan Approval; West Virginia; Regional Haze State Implementation Plan for the Second Implementation Period, 90 Fed. Reg. 16,478 (Apr. 18, 2025) [Docket ID No. EPA-R03-OARS-2025-0174] (May 19, 2025) [hereinafter “Conservation Groups West Virginia Comments”] (attached as Ex. 2). As explained in those comments, which we attach and incorporate by reference, EPA’s new policy cannot constitute the “best reading” of the CAA’s regional haze provision because the policy violates the Act’s text, context and goal.⁴ Id. at 6-15. The new policy is also inconsistent with the requirements of the RHR⁵Id. at 15-17. and further violates the Act’s procedural requirements as it is contrary to national policy and inconsistent with second planning period actions taken by almost every other EPA region for this planning period, including prior actions by EPA Region 8 on other states.⁶Id. at 18-23. For all these same reasons, EPA’s reliance on its new policy to approve South Dakota’s SIP Revision is arbitrary, capricious and violates the Clean Air Act.⁷42 U.S.C. § 7607(d)(9)(A), (C).

As explained in the Conservation Groups’ State Comments, the SIP Revision violates the Clean Air Act and Regional Haze Rule for a number of reasons.⁸See generally Conservation Orgs State Comments. By relying solely on its newly announced policy to justify its approval here, EPA ignores these significant errors in South Dakota’s SIP Revision. EPA thus shirks its duty under the Act to substantively review and only approve SIPs that comply with the Clean Air Act.⁹42 U.S.C 7491; Id. §§ 7410(c)(1), (k)(3), (l); Arizona ex rel. Darwin v. EPA, 815 F.3d 519, 525 (9th Cir. 2016) (explaining that EPA must substantively review all SIP submissions “for consistency with the statute and regulations” (citing 42 U.S.C. § 7410(c)(1)(A)).

Finally, the Conservation Groups urge EPA to review and incorporate the National Park Service’s recommendation in their consultation comments on the SIP Revision, which indicate that installing SNCR on the GCC Dacotah Cement facility would be cost effective. NPS states that DANR:

…estimated costs using a 3.5% interest rate [that] resulted in estimates of $5,496/ton of SO2 removed for semi-dry scrubbing and $6,394/ton for wet scrubbing. Nonetheless, these costs are within the range of cost-effectiveness thresholds selected by other states. States that have selected thresholds include Texas at $5,000/ton, New Mexico at $7,000/ton, and Colorado and Oregon at $10,000/ton.¹⁰South Dakota Regional Haze State Implementation Plan, Appendix A-2 at 24.

The Conservation Groups agree with the NPS analysis that the DANR estimates are cost effective. Moreover, we believe a $10,000/ton threshold is appropriate to ensure reasonable progress determinations address the cumulative nature of visibility impairment.

The Conservation Groups appreciate EPA’s consideration of these comments. Please do not hesitate to contact us with any questions.

• 1
  Nat’l Parks Conservation Ass’n, et al., Conservation Organizations’ Comments on South Dakota’s Proposed Regional Haze State Implementation Plan for the Second Planning Period (Apr. 20, 2022) [hereinafter “Conservation Orgs State Comments”] (attached as Ex. 1).
• 2
  90 Fed. Reg. 20,434.
• 3
  Nat’l Parks Conservation Ass’n, et al., Comments on Proposed Air Plan Approval; West Virginia; Regional Haze State Implementation Plan for the Second Implementation Period, 90 Fed. Reg. 16,478 (Apr. 18, 2025) [Docket ID No. EPA-R03-OARS-2025-0174] (May 19, 2025) [hereinafter “Conservation Groups West Virginia Comments”] (attached as Ex. 2).
• 4
  Id. at 6-15.
• 5
  Id. at 15-17.
• 6
  Id. at 18-23.
• 7
  42 U.S.C. § 7607(d)(9)(A), (C).
• 8
  See generally Conservation Orgs State Comments.
• 9
  42 U.S.C 7491; Id. §§ 7410(c)(1), (k)(3), (l); Arizona ex rel. Darwin v. EPA, 815 F.3d 519, 525 (9th Cir. 2016) (explaining that EPA must substantively review all SIP submissions “for consistency with the statute and regulations” (citing 42 U.S.C. § 7410(c)(1)(A)).
• 10
  South Dakota Regional Haze State Implementation Plan, Appendix A-2 at 24.