California Code, Health and Safety Code - HSC § 41650

(a) The state board shall adopt the nonattainment area plan approved by a designated air quality planning agency as part of the state implementation plan, unless the state board finds, after a public hearing, that the nonattainment area plan will not meet the requirements of the Clean Air Act (42 U.S.C. Sec. 7401 et seq.).

(b) The primary responsibility for determining whether a control measure is reasonably available shall be vested in the public agency which has the primary responsibility for implementation of that control measure. The determination of reasonably available control measure by the public agency responsible for implementation shall be conclusive, unless the state board finds after public hearing that such determination will not meet the requirements of the Clean Air Act.