(a) This part implements the provisions of section 18 of the Occupational Safety and Health Act of 1970 (“OSH Act” or the “Act”) which provides for State plans for the development and enforcement of State occupational safety and health standards. These plans must meet the criteria in section 18(c) of the Act, and part 1902 of this chapter (for plans covering both private sector and State and local government employers) or part 1956 of this chapter (for plans covering only State and local government employers), either at the time of submission or - where the plan is developmental - within the three year period immediately following commencement of the plan's operation. Approval of a State plan is based on a finding that the State has, or will have, a program, pursuant to appropriate State law, for the adoption and enforcement of State standards that is “at least as effective” as the Federal program.

(b) When submitting plans, the States provide assurances that they will continue to meet the requirements in section 18(c) of the Act and part 1902 or part 1956 of this chapter for a program that is “at least as effective” as the Federal. Such assurances are a fundamental basis for approval of plans. (See §§ 1902.3 and 1956.2 of this chapter.) From time to time after initial plan approval, States will need to make changes to their plans. This part establishes procedures for submission and review of State plan supplements documenting those changes that are necessary to fulfill the State's assurances, the requirements of the Act, and part 1902 or part 1956 of this chapter.

(c) Changes to a plan may be initiated in several ways. In the case of a developmental plan, changes are required to document establishment of those necessary structural program components that were not in place at the time of plan approval. These commitments are included in a developmental schedule approved as part of the initial plan. These “developmental changes” must be completed within the three year period immediately following the commencement of operations under the plan. Another circumstance requiring subsequent changes to a State plan would be the need to keep pace with changes to the Federal program, or “Federal Program Changes.” A third situation would be when changes are required as a result of the continuing evaluation of the State program. Such changes are called “evaluation changes.” Finally, changes to a State program's safety and health requirements or procedures initiated by the State without a Federal parallel could have an impact on the effectiveness of the State program. Such changes are called “State-initiated changes.” While requirements for submission of a plan supplement to OSHA differ depending on the type of change, all supplements are processed in accordance with the procedures in § 1953.6.