40 CFR § 51.152 - Contingency plans.
(a) Each contingency plan must -
(1) Specify two or more stages of episode criteria such as those set forth in appendix L to this part, or their equivalent;
(2) Provide for public announcement whenever any episode stage has been determined to exist; and
(3) Specify adequate emission control actions to be taken at each episode stage. (Examples of emission control actions are set forth in appendix L.)
(b) Each contingency plan for a Priority I region must provide for the following:
(1) Prompt acquisition of forecasts of atmospheric stagnation conditions and of updates of such forecasts as frequently as they are issued by the National Weather Service.
(2) Inspection of sources to ascertain compliance with applicable emission control action requirements.
(3) Communications procedures for transmitting status reports and orders as to emission control actions to be taken during an episode stage, including procedures for contact with public officials, major emission sources, public health, safety, and emergency agencies and news media.
(c) Each plan for a Priority IA and II region must include a contingency plan that meets, as a minimum, the requirements of paragraphs (b)(1) and (b)(2) of this section. Areas classified Priority III do not need to develop episode plans.
(d) Notwithstanding the requirements of paragraphs (b) and (c) of this section, the Administrator may, at his discretion -
(1) Exempt from the requirements of this section those portions of Priority I, IA, or II regions which have been designated as attainment or unclassifiable for national primary and secondary standards under section 107 of the Act; or
(2) Limit the requirements pertaining to emission control actions in Priority I regions to -
(i) Urbanized areas as identified in the most recent United States Census, and
(ii) Major emitting facilities, as defined by section 169(1) of the Act, outside the urbanized areas.