Section, act July 14, 1955, ch. 360, title II, § 211, as added Nov. 21, 1967,
Pub. L. 90–148, § 2,
81 Stat. 503, provided for a national emissions standards study for stationary sources to be conducted by the Secretary, with a report and recommendations to be submitted to the Congress by Nov. 21, 1969, and for a study of the feasibility of controls for jet and piston aircraft engines, with a report thereon to Congress by Nov. 21, 1968.