(a) The affected facility to which the provisions of this subpart apply is each superphosphoric acid plant having a design capacity of more than 15 tons of equivalent P2O5 feed per calendar day. For the purpose of this subpart, the affected facility includes any combination of: evaporators, hot wells, acid sumps, and cooling tanks.
(b) Any facility under paragraph (a) of this section that commences construction or modification after October 22, 1974, is subject to the requirements of this subpart. [42 FR 37937, July 25, 1977, as amended at 48 FR 7129, Feb. 17, 1983]