40 CFR § 62.15910
What must I do if I close my SSI unit and then restart it?
June 9, 2020
(a) If you close your SSI unit but will restart it prior to the final compliance, you must submit a final control plan and achieve final compliance as specified in §62.15875.
(b) If you close your SSI unit but will restart it after the final compliance date, you must complete emission control retrofits and meet the emission limits, emission standards, and operating limits on the date your unit restarts operation.