09/27/2017 - Regulatory Rollback

Ozone National Ambient Air Quality Standards

by EELP Staff

The Environmental & Energy Law Program is tracking the environmental regulatory rollbacks of the Trump administration. Click here for the list of rules we are following. If you’re a reporter and would like to speak with an expert on this rule, please email us.

Why it Matters

Ground-level ozone, or smog, is formed when pollution from vehicles, power plants, and other industrial sources reacts with sunlight. It can aggravate asthma and cause other respiratory problems, especially in children who are playing outdoors and people who already have lung problems. Stricter ozone standards were set to take effect Oct. 1, 2017.

Current Status

Dec. 6, 2019 EPA publishes a rule finalizing implementation requirements for the 2015 NAAQS. The final rule is effective on February 4, 2019.

Feb. 4, 2019 Environmental groups ask the D.C. Circuit to review EPA’s final implementation rule for the 2015 NAAQS.


Oct. 26, 2015 EPA issues a rule to tighten national ozone pollution standards based on the latest science. The new standards are set to take effect Oct. 1, 2017.

Sep. 14, 2016 Murray Energy sues EPA challenging the new standards. Murray Energy Corp. v. EPA, Case No. 15-1385 (D.C. Cir.)

Nov. 17, 2016 EPA proposes nonattainment classification thresholds and compliance timelines for the 2015 rule.

Trump Era

April 7, 2017 EPA asks the Court to delay the oral argument scheduled for April 19, 2017. EPA said it “intends to closely review the 2015 Rule, and the prior positions taken by the Agency with respect to the 2015 Rule may not necessarily reflect its ultimate conclusions after that review is complete.”

April 11, 2017 The Court removes the argument from its calendar and orders EPA to provide status reports every 90 days, starting from the date of this order.

June 6, 2017 EPA Administrator Pruitt announces EPA will delay the new standards by one year.

June 28, 2017 EPA publishes a formal notice in the Federal Register that it will delay implementation of the ozone standard by one year to Oct. 1, 2018.

July 12, 2017 Environmental groups sue EPA over the delay of the ozone rule. American Lung Association et al v. EPA, Case No. 17-1172 (D.C. Cir.).

Aug. 1, 2017 The Attorney General of New York announces he and 15 others are suing EPA over the delay of the rule.

Aug. 2, 2017 In a press release, EPA announces it will walk back the national delay and proceed as originally scheduled.

Oct. 1, 2017 Deadline for EPA to make all compliance determinations.

Nov. 16, 2017 EPA certifies some 2,650 areas as in compliance (or in attainment) of the rule. It does not designate any non-attainment areas or release a timeline for doing so, which is necessary to “start the clock for states to come up with cleanup plans.

Dec. 4, 2017 A coalition of public health and environmental groups sue EPA for its delay of designating non-attainment areas.

Dec. 5, 2017 New York attorney general Eric T. Schneiderman announces he and 13 other state attorneys general and the District of Columbia sued EPA for its failure to designate non-attainment areas. Northern District of California, Case 3:17-cv-06936

Dec. 19, 2017 The D.C. Circuit Court orders EPA to “file a status report identifying with precision and specificity when it plans to file a final rule establishing air quality designations” by Jan. 12, 2018, for the areas that were not covered by the attainment designations made on Nov. 16, 2017.

Dec. 22, 2017 EPA announces it sent letters to areas not covered by the attainment designations, seeking further information from them in order to make a designation, with a 120-day deadline for response.

Jan. 5, 2018 EPA publishes notice that it will make the remaining attainment designations by April 30, 2018.

Jan. 19, 2018 EPA files declarations with both the Northern District of California and D.C Circuit stating it will make all remaining attainment designations by April 30, 2018, with the exception of eight counties in the San Antonio, TX area, which it will designate by Aug. 10, 2018.

Feb. 7, 2018 A three-judge panel of the D.C. Circuit Court orders EPA to file a progress report by May 15, 2018 “detailing the status of all final designations for the 2015 ozone national ambient air quality standards.”

March 1, 2018 EPA issues a final rule setting the compliance timelines for areas in nonattainment and “establishing the air quality thresholds that define the classifications assigned to all nonattainment areas,” which were proposed in 2016 by the Obama EPA. The rule will take effect on May 8, 2018.

March 12, 2018 A Northern District of California District Court rules that EPA cannot delay the Texas counties, or any others, and must make all designations by July 17, 2018.

March 30, 2018 EPA publishes notice that it will finish designations for the Texas counties by the court-ordered deadline, and lists an intended designation for each area. The notice is open for public comment until April 30, 2018.

April 30, 2018 EPA announces it had made all remaining designations with the exception of the eight Texas counties. Fifty-one areas were in nonattainment, starting a clock for them to make improvements.

May 22, 2018 Fifteen states and the District of Columbia file a complaint with the U.S. Circuit Court of Appeals for the D.C. Circuit, saying EPA had not listed its new ozone designations in the Federal Register. This listing is required to start the 60-day compliance clock. On May 24, 2018a coalition of public health and environmental groups file in agreement with the states.

June 4, 2018 EPA publishes in the Federal Register designations for “all remaining areas, except for eight counties in the San Antonio, Texas metropolitan area,” starting a 60-day compliance clock for the designated areas.

June 26, 2018 EPA publishes a call for information in the Federal Register announcing it is preparing an Integrated Review Plan and Integrated Science Assessment as part of its Ozone NAAQs review and inviting interested parties to submit information. They are taking comments until Aug. 27, 2018It also publishes a call for information to facilitate “consideration of any adverse public health, welfare, social, economic, or energy effects which may result from various strategies for attainment and maintenance” of the Ozone NAAQs. The comment period for this information runs through Oct. 24, 2018.

July 3, 2018 EPA sends the final draft of its implementation regulations for 2015 ground-level ozone standard to the White House Office of Management and Budget for review.

July 3, 2018 The Court of Appeals for the District of Columbia returns the Murray Energy Corp. v. EPA litigation to its active docket. Murray Energy Corp. v. EPA, No. 15-1385 (D.C. Cir.).

July 17, 2018 EPA completes designations for the eight remaining counties in Texas that had not yet been designated. EPA designates Bexar County (where San Antonio, Texas is located) as a nonattainment area and the remaining seven counties as attainment/unclassifiable areas. The designations are posted in the Federal Register on July 25, 2018.

July 27, 2018 EPA publishes a request for nominations for the Clean Air Scientific Advisory Committee (CASAC) Ozone Review Panel. The review panel provides scientific and technical advice and recommendations on NAAQs and air quality criteria. “The Panel will be charged with reviewing the science and policy assessments, and related documents, that form the basis for the EPA’s review of the Ozone NAAQS” announced on June 26, 2018 and expected to be completed by late 2020. This panel will be subject to Pruitt’s science advisory committee policy limiting who can serve on EPA advisory panels. For more information on this Administration’s new approach to science advising, see the EELP post on advisory panels.

Aug. 1, 2018 EPA files a status report with the D.C. Circuit indicating that “the appropriate EPA officials have reviewed the 2015 [Ozone NAAQS] Rule and have determined that at this time, EPA does not intend to revisit the 2015 Rule.” In this filing, EPA indicated it intends to address background ozone and the “relative contribution of natural and anthropogenic ozone to design values” in its new review of the Ozone NAAQS. “EPA anticipates revisiting both the question of when background concentrations interfere with attainment of the NAAQS and the question of how to consider potential interference with attainment in deciding whether or how to revise the NAAQS.” Murray Energy Corp. v. EPA, No. 15-1385 (D.C. Cir.).

Aug. 1, 2018 Clean Wisconsin files a suit challenging the attainment designations of counties in Wisconsin.

Aug. 2, 2018 Illinois Attorney General Madigan and the City of Chicago files suit challenging attainment designations made for counties in Indiana, Illinois, and Wisconsin.

Three lawsuits challenging designations have also been filed by environmental groups Sierra Club, Environmental Law & Policy Center, Respiratory Health Association, and the city of Sunland Park, N.M., and Familias Unidas del Chamizal, an El Paso, Texas.

Aug. 28, 2018 Texas Attorney General Paxton files suit challenging attainment designations made for Bexar County including the San Antonio area.

Dec. 6, 2019 EPA publishes a rule finalizing implementation requirements for the 2015 NAAQS. The final rule is effective on February 4, 2019.

Feb. 4, 2019 Environmental groups ask the D.C. Circuit to review EPA’s final implementation rule for the 2015 NAAQS.