Control technology means measures, processes, methods, systems, or techniques to limit the emission of hazardous air pollutants including, but not limited to, measures which:
(1) Reduce the quantity, or eliminate emissions, of such pollutants through process changes, substitution of materials or other modifications;
(2) Enclose systems or processes to eliminate emissions;
(3) Collect, capture, or treat such pollutants when released from a process, stack, storage or fugitive emissions point;
(4) Are design, equipment, work practice, or operational standards (including requirements for operator training or certification) as provided in 42 U.S.C. 7412(h); or
(5) Are a combination of paragraphs (1) through (4) of this definition.
40 CFR § 63.51
Terms used in 63.50 through 63.56 that are not defined in this section have the meaning given to them in the Act, or in subpart A of this part.