On June 28, 2017, EPA published notice in the Federal Register of its decision to extend by one year the deadline for promulgating initial area designations for the 2015 Ozone National Ambient Air Quality Standards (NAAQS). Under the extension, the new deadline for promulgating initial area attainment/nonattainment designations is October 1, 2018.

The October 2015 Ozone NAAQS revised the 8-hour primary and secondary ozone standards. The primary standard was lowered from 0.075 parts per million (ppm) to 0.070 ppm. The secondary standard was revised to make it identical in all respects to the revised primary standard. At this point, the prior Ozone NAAQS that were set in 2008 remain effective.

The prior deadline for states to submit designation recommendations to EPA for the 2015 Ozone NAAQS was October 1, 2016. EPA notes it has been evaluating the state recommendations and conducting additional analyses to determine whether any of the state recommendations need to be modified. The Federal Register notice states EPA determined there is insufficient information to complete those analyses and designations by October 1, 2017, and thus the one year extension is justified. With respect to the additional analyses, EPA notes it is evaluating a “host of complex issues regarding the 2015 Ozone NAAQS and its implementation, such as understanding the role of background ozone levels and appropriately accounting for interstate transport.” In a related action, EPA established an Ozone Cooperative Compliance Task Force to assist in developing additional flexibilities for states in complying with the ozone standard. The task force, along with the extension of the designation deadline, are identified in a June 6, 2017 letter from Administrator Pruitt to state governors.

Environmental interest groups fear the new task force and EPA will ultimately recommend weakening the 2015 Ozone Standard. EPA has not yet finalized a November 2016 Obama-era proposed rule on implementation plan protocols for states relating to the 2015 Ozone Standard. The one-year extension of the deadline for promulgating designations may in fact provide EPA with the necessary time to re-evaluate the 2015 standard. The 2015 Ozone Standard is also being challenged in litigation in the United States Court of Appeals for the D.C. Circuit.

Additionally, there is pending legislation in Congress that would delay implementation of the 2015 Ozone NAAQS until 2025. The legislation has passed the House and as of July 19, 2017, is referred to the Senate Committee on Environment and Public Works. The pending legislation would set 10-year intervals on revising NAAQS, and make revisions to the considerations for revising NAAQS, including consideration of technological feasibility.