Applicability and designation of affected facility.

(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 P 2 O 5 feed per calendar day. (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; 80 FR 50433, Aug. 19, 2015]