# 52.1928 Visibility protection.
(a) The following portions of the Oklahoma Regional Haze (RH) State Implementation Plan submitted on February 19, 2010 are disapproved:
(1) The SO<sub>2</sub> BART determinations for Units 4 and 5 of the Oklahoma Gas and Electric (OG&E) Muskogee plant; Units 1 and 2 of the OG&E Sooner plant; and Units 3 and 4 of the American Electric Power/Public Service Company of Oklahoma (AEP/PSO) Northeastern plant;
(2) The long-term strategy for regional haze;
(3) “Greater RP Alternative Determination” (Section VI.E);
(4) Separate executed agreements between ODEQ and OG&E, and ODEQ and AEP/PSO entitled “OG&E RH Agreement, Case No. 10-024, and “PSO RH Agreement, Case No. 10-025,” housed within Appendix 6-5 of the RH SIP; and
(b) The portion of the State Implementation Plan pertaining to adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility, submitted on May 10, 2007 and supplemented on December 10, 2007 is disapproved.
(c) The SO<sub>2</sub> BART requirements for Units 4 and 5 of the Oklahoma Gas and Electric (OG&E) Muskogee plant, and Units 1 and 2 of the OG&E Sooner plant; the deficiencies in the long-term strategy for regional haze; and the requirement for a plan to contain adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility are satisfied by § 52.1923.
(d) The revision to the Regional Haze plan submitted on June 20, 2013 concerning Units 3 and 4 of the American Electric Power/Public Service Company of Oklahoma (AEP/PSO) Northeastern plant is approved. For this source the plan addresses requirements for BART and adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility. As called for in the plan if a SO<sub>2</sub> emission limit of 0.3 lb/MMBtu is not met the State will obtain and/or identify additional SO<sub>2</sub> reductions within Oklahoma to the extent necessary to achieve the anticipated visibility benefits estimated by the Central Regional Air Planning Association (CENRAP).
(e) The portion of the State Implementation Plan pertaining to adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility for the 2015 ozone national ambient air quality standard (NAAQS), submitted on October 25, 2018, and clarified in a letter dated January 5, 2021, is approved.
(f) The portions of the State Implementation Plans pertaining to adequate provisions to prohibit emissions from interfering with measures required in another state to protect visibility for the 2010 1-hour SO<sub>2</sub> NAAQS, submitted on January 28, 2015, and the 2012 PM<sub>2.5</sub> NAAQS, submitted on June 16, 2016, are disapproved. The deficiencies in the Oklahoma SIP that form the basis of our disapproval of the interstate visibility transport portions of these two State Implementation Plan submissions are addressed by § 52.1923.
[76 FR 81759, Dec. 28, 2011, as amended at 79 FR 12954, Mar. 7, 2014; 81 FR 349, Jan. 5, 2016; 87 FR 26680, May 5, 2022; 90 FR 56009, Dec. 5, 2025]