(a) On and before March 9, 2021, for affected sources that commenced construction or reconstruction on or before September 10, 2020, you must be in compliance with the emissions limitations, work practice standards, and operation and maintenance requirements in this subpart at all times, except during periods of startup and shutdown. After March 9, 2021, for affected sources that commenced construction or reconstruction on or before September 10, 2020, and upon startup for affected sources that commenced construction or reconstruction after September 10, 2020, you must be in compliance with the emissions limitations, work practice standards, and operation and maintenance requirements in this subpart at all times.

(b) During the period between the compliance date specified for your iron and steel foundry in § 63.7683 and the date when applicable operating limits have been established during the initial performance test, you must maintain a log detailing the operation and maintenance of the process and emissions control equipment.

(c) On and before March 9, 2021, for affected sources that commenced construction or reconstruction on or before March 9, 2021, you must develop a written startup, shutdown, and malfunction plan according to the provisions in § 63.6(e)(3). The startup, shutdown, and malfunction plan also must specify what constitutes a shutdown of a cupola and how to determine that operating conditions are normal following startup of a cupola. After March 9, 2021, for affected sources that commenced construction or reconstruction on or before September 10, 2020, and upon startup for affected sources that commenced construction or reconstruction after September 10, 2020, the startup, shutdown, and malfunction plan requirements no longer apply.