(a) Except as provided in (b) of this section, the department shall issue only a single operating permit to a stationary source, regardless of whether the stationary source contains a single emissions unit or multiple emissions units.
(b) The department may, upon request of a stationary source owner or operator, issue more than one permit for the stationary source. Substantive and procedural requirements otherwise applicable to a stationary source remain applicable regardless of whether the stationary source owner and operator apply for one or more permits.