An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

General Conformity

General Conformity Training Module 4.2: State and Tribal Conformity Implementation

States and tribes are allowed, but not required, to have their own conformity implementation plan. If a state or tribe adopts an implementation plan for the conformity program, the plan must be at least as stringent as the federal regulations and can be no more stringent than the federal regulations unless the requirements apply to non-federal sources as well. Unless the state or tribe has a program to ensure that all entities conform to the SIP/TIP, their implementation plan would be similar to the federal requirements. The state or tribe can use their own plan to identify the appropriate reviewing agencies and other procedural matters. States that already have approved general conformity SIP submit a revision rescinding the SIP and stating that 40 CFR part 93 will apply.

Once the plan is adopted and approved by EPA as a SIP/TIP revision, federal agencies are obligated to meet the requirements of the state or tribal plan. Since the state and tribal programs are approved as part of the SIP/TIP for the area, they remain effect until EPA approves their revisions even though EPA revises the federal rules. States with an approved program must revise their plans before a federal agency can take advantage of any new provisions of the federal regulations. Since the federal regulations apply when the state or tribe does not have a program, deletion of a state or tribal program would not have an environmental effect.