(a) State review of implementation plans which relate to major fuel burning sourcesAs expeditiously as practicable but not later than one year after August 7, 1977, each State shall review the provisions of its implementation plan which relate to major fuel burning sources and shall determine—
the extent to which compliance with requirements of such plan is dependent upon the use by major fuel burning stationary sources of petroleum products or natural gas,
the extent to which such plan may reasonably be anticipated to be inadequate to meet the requirements of this chapter in such State on a reliable and long-term basis by reason of its dependence upon the use of such fuels, and
(b) Plan revision
Not later than eighteen months after August 7, 1977, the Administrator shall review the submissions of the States under subsection (a) and shall require each State to revise its plan if, in the judgment of the Administrator, such plan revision is necessary to assure that such plan will be adequate to assure compliance with the requirements of this chapter in such State on a reliable and long-term basis, taking into account the actual or potential prohibitions on use of petroleum products or natural gas, or both, under any other authority of law.