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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

EPA in Indiana

Indiana (Part 63) MACT Standards Delegations

Clean Air Act Section 112 Major and Area Source Standards

EPA's final delegation approval of Section 112 NESHAP standards for Indiana constitutes a program of straight delegation of all existing and future air toxic standards regardless of a source's Part 70 (Title V) applicability, with the exception of Section 112(r).

For future 112 NESHAP standards for which IDEM intends to accept delegation, EPA will automatically delegate the authority to implement a standard to the State by letter unless IDEM notifies EPA differently within 45 days of EPA final promulgation of the standard. Upon receipt of the EPA letter, IDEM will be responsible for the implementation of the standard. IDEM will then adopt the standard unchanged from the Federal standard into State regulations as expeditiously as practicable. IDEM will submit proof of rule adoption to EPA. EPA will respond with a letter delegating enforcement authority to the State. EPA will enforce the standard until such time the State has been delegated the enforcement authority.

IDEM has chosen not to take full or partial delegation of newly promulgated area source MACT standards.

112(L) Delegations to Indiana through a state rule that adjusts the MACT standard

Federal Register Documents for Approval of Section 112(l) Program of Delegation​

The Indiana Database will be made available as a spreadsheet.