These amendments would address when a major source can become an area source, and, thus, become not subject to national emission standards for hazardous air pollutants (NESHAP) for major sources under Clean Air Act (CAA) section 112. The amendments implement the EPA's plain language reading of the CAA section 112 definitions of "major" and "area" sources as discussed in the January 2018 William Wehrum memorandum titled "Reclassification of Major Sources as Area Sources Under Section 112 of the Clean Air Act." (See notice in 83 FR 5543, February 8, 2018.) This action provides an opportunity for interested persons to provide comment on many of the same issues covered in the 2007 NESHAP: General Provision Amendments (72 FR 69, January 3, 2007).