104 STAT. 2686 PUBLIC LAW 101-549—NOV. 15, 1990 ency with onshore regulations. The authority of this subsection shall supersede section 5(a)(8) of the Outer Continental Shelf Lands Act but shall not repeal or modify any other Federal, State, or local authorities with respect to air quality. Each requirement established under this section shall be treated, for purposes of sections 113, 114, 116, 120, and 304, as a standard under section 111 and a violation of any such requirement shall be considered a violation of section 111(e). "(2) EXEMPTIONS.—The Administrator may exempt an OCS source from a specific requirement in effect under regulations under this subsection if the Administrator finds that compliance with a pollution control technology requirement is technically infeasible or will cause an unreasonable threat to health and safety. The Administrator shall make written findings explaining the basis of any exemption issued pursuant to this subsection and shall impose another requirement equal to or as close in stringency to the original requirement as possible. The Administrator shall ensure that any increase in emissions due to the granting of an exemption is offset by reductions in actual emissions, not otherwise required by this Act, from the same source or other sources in the area or in the corresponding onshore area. The Administrator shall establish procedures to provide for public notice and comment on exemptions proposed pursuant to this subsection. Regulations. "(3) STATE PROCEDURES. — Each State adjacent to an OCS source included under this subsection may promulgate and submit to the Administrator regulations for implementing and enforcing the requirements of this subsection. If the Administrator finds that the State regulations are adequate, the Administrator shall delegate to that State any authority the Administrator has under this Act to implement and enforce such requirements. Nothing in this subsection shall prohibit the Administrator from enforcing any requirement of this section. "(4) DEFINITIONS.—For purposes of subsections (a) and (b)— "(A) OUTER CONTINENTAL SHELF.—The term 'Outer Continental Shelf has the meaning provided by section 2 of the Outer Continental Shelf Lands Act (43 U.S.C. 1331). "(B) CORRESPONDING ONSHORE AREA.—The term 'corresponding onshore area' means, with respect to any OCS source, the onshore attainment or nonattainment area that is closest to the source, unless the Administrator determines that another area with more stringent requirements with respect to the control and abatement of air pollution may reasonably be expected to be affected by such emissions. Such determination shall be based on the potential for air pollutants from the OCS source to reach the other onshore area and the potential of such air pollutants to affect the efforts of the other onshore area to attain or maintain any Federal or State ambient air quality standard or to comply with the provisions of part C of title I. "(C) OUTER CONTINENTAL SHELF SOURCE. — The terms 'Outer Continental Shelf source' and 'OCS source' include any equipment, activity, or facility which— "(i) emits or has the potential to emit any air pollutant, "(ii) is regulated or authorized under the Outer Continental Shelf Lands Act, and "(iii) is located on the Outer Continental Shelf or in or on waters above the Outer Continental Shelf.