Pursuant to the Federal Clean Air Act (CAA or the Act), the Environmental Protection Agency (EPA) is approving the CAA section 111(d)/129 state plan submitted by the State of Texas for sources subject to the Other Solid Waste Incineration Units (OSWI) Emission Guidelines (EG). The Texas OSWI plan was submitted to fulfill State obligations under CAA section 111(d)/129 to implement and enforce the requirements under the OSWI EG. The EPA is approving the state plan in part and amending the agency regulations in accordance with the requirements of the CAA.

The U.S. Environmental Protection Agency (EPA) is proposing to revise the EPA's regulatory definition of volatile organic compounds (VOC) under the Clean Air Act (CAA). This action proposes to add (2E)- 1,1,1,4,4,4-hexafluorobut-2-ene (also known as trans-1,1,1,4,4,4- hexafluorobut-2-ene, and HFO-1336mzz(E); CAS number 66711-86-2) to the list of compounds excluded from the regulatory definition on the basis that this compound makes a negligible contribution to tropospheric ozone (O<INF>3</INF>) formation.

The Environmental Protection Agency (EPA) proposes three actions pursuant to section 181(b)(2) of the Clean Air Act (CAA) related to seven areas classified as ``Serious'' for the 2008 ozone National Ambient Air Quality Standards (NAAQS). First, the Agency proposes to determine that one area attained the 2008 ozone NAAQS by the July 20, 2021, attainment date.

The Environmental Protection Agency (EPA) is re-proposing a document, first proposed in 2016, which would remove the emergency affirmative defense provisions found in the regulations for state and federal operating permit programs under the Clean Air Act (CAA). The purpose of these provisions has been to establish an affirmative defense that sources can assert in civil enforcement cases when noncompliance with certain emission limitations in operating permits occurs because of qualifying ``emergency'' circumstances.