(1) As used in subsection (3) of this section, the term "bubble" means an air pollution control system which permits aggregate measurements of allowable emissions, for a single category of pollutant, for emissions points from a specified emissions-generating facility or facilities. Individual point source emissions levels from such specified facility or facilities may be modified provided that the aggregate limit for the specified sources is not exceeded.

(2) Whenever any regulation relating to emission standards or other requirements for the control of emissions is adopted which provides for compliance with such standards or requirements no later than a specified time after the date of adoption of the regulation, the appropriate activated air pollution control authority or, if there be none, the department of ecology shall, by permit or regulatory order, issue to air contaminant sources subject to the standards or requirements, schedules of compliance setting forth timetables for the achievement of compliance as expeditiously as practicable, but in no case later than the time specified in the regulation. Interim dates in such schedules for the completion of steps of progress toward compliance shall be as enforceable as the final date for full compliance therein.

(3) Wherever requirements necessary for the attainment of air quality standards or, where such standards are not exceeded, for the maintenance of air quality can be achieved through the use of a control program involving the bubble concept, such program may be authorized by a regulatory order or orders or permit issued to the air contaminant source or sources involved. Such order or permit shall only be authorized after the control program involving the bubble concept is accepted by [the] United States environmental protection agency as part of an approved state implementation plan. Any such order or permit provision shall restrict total emissions within the bubble to no more than would otherwise be allowed in the aggregate for all emitting processes covered. The orders or permits provided for by this subsection shall be issued by the department or the authority with jurisdiction. If the bubble involves interjurisdictional approval, concurrence in the total program must be secured from each regulatory entity concerned.

Finding—1991 c 199: See note following RCW 70A.15.1005.

Use of emission credits to be consistent with bubble program: RCW 70A.15.6230.