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D.C. Circuit Largely Upholds EPA’s 2015 Ozone Standards (4)

Aug. 23, 2019, 2:32 PMUpdated: Aug. 23, 2019, 9:07 PM

A federal appeals court has largely upheld national ozone standards, sending the public-welfare-protection aspect of the limits back to the Environmental Protection Agency.

The U.S. Court of Appeals for the District of Columbia Circuit ruled in a per curiam opinion that the Obama-era EPA largely followed the law and science when it tightened the ozone standard under the Clean Air Act to 70 parts per billion in 2015.

The ruling sends just the secondary standard that protects animals, crops, vegetation, and buildings back to the agency, while upholding the primary standard that protects public health.

“EPA has adequately explained why on the record before it the revised standard is requisite to protect the public health,” the court said.

In vacating the secondary limits, the court said the Environmental Protection Agency didn’t follow the recommendations of its Clean Air Scientific Advisory Committee, or CASAC, that is charged with reviewing the limits.

“In setting the secondary standard, EPA failed to justify its decision to use a three-year average benchmark without lowering the level to account for single-year spikes in ozone exposures, and it arbitrarily declined to set a level to protect against adverse welfare effects associated with visible leaf injury,” the court said.


The rule was challenged by Murray Energy Corp., several states, and industry groups. Three judges, two of whom were appointed by President Barack Obama and one by President George W. Bush, were unpersuaded by the other arguments made by several states and the energy industry to fully overturn the 2015 limits on ozone.

If they had been fully successful in their challenge, the EPA would have to return to the drawing board to rework its standards for ozone, a lung irritant that is the main ingredient in smog.

The court rejected their arguments that the EPA failed to adequately explain its reasons for tightening the 2008 standard of 75 parts per billion.

“While Industry Petitioners challenge the use of epidemiologic evidence given the uncertainties presented in these studies, even CASAC concluded that the epidemiologic evidence would have alone been strong enough to justify revision” of the 2008 National Ambient Air Quality Standards (NAAQS), the court said.

The 2015 limits at the center of this case reduced allowable ozone levels by nearly 7% from the previous NAAQS, which were set at 75 parts per billion in 2008.

Counties and other areas out of compliance with federal ozone standards must take efforts to reduce ozone pollution, which is caused by byproducts from burning fossil fuels. That can mean imposing new pollution control measures on businesses and power plants or setting emissions limits for cars and trucks.

Murray Energy didn’t respond to requests for comment. The EPA said it was reviewing the decision.

Applauding the decision was California Attorney General Xavier Becerra, who led a coalition of seven states and Washington, D.C., to defend the ozone standards.

“For many, poor air quality is not just upsetting, but debilitating. It means missed days of school, work, and countless other opportunities,” Becerra said in an Aug. 23 statement. “Today’s decision strikes down an attempt by corporate interests to weaken ozone standards and continue to collect massive profits at the expense of our children’s health.”

‘Completely and Utterly’

The environmental groups, which were defending the federal standards on EPA’s behalf, were pleased that the court “completely and utterly” rejected the arguments put forth by the industry petitioners that were trying to overturn the public health protections.

It is a “big deal” that the court rejected the industry’s argument that EPA look at background ozone levels caused by pollution from wildfires, said Seth Johnson, staff attorney with the legal nonprofit Earthjustice, which argued on behalf of the health and environmental groups to make the federal limits more protective than the current levels.

“Congress intended NAAQS to be national ambient air quality standards, and EPA is not required to ‘tailor national regulations to fit each region or locale,’” the court wrote, adding, “because the Clean Air Act prohibits EPA from adjusting for background ozone in setting the NAAQS, EPA did not act unlawfully or arbitrarily and capriciously in setting the NAAQS without regard for background ozone.”

Johnson said the groups were disappointed that the court rejected their petition to make the limits more protective, saying the court thought the EPA had done an adequate job of protecting vulnerable populations like children and elderly who are prone to asthma due to high ground-level ozone levels.

Ozone Review

The court’s decision will most certainly influence the EPA as it is under a self-imposed deadline to decide by December 2020 whether to maintain the 2015 ozone limits or to tighten them.

CASAC is racing to meet that deadline.

“The decision emphasizes the importance of accurately following the science,” Johnson said.

The judges on the panel were Thomas B. Griffith, a President George W. Bush appointee, and Cornelia T.L. Pillard and Robert L. Wilkins, appointed by Obama.

The case is Murray Energy Corp. v. EPA, D.C. Cir., No. 15-1385, 8/23/19.

(Adds names of presidents who appointed the judges in last paragraph.)

To contact the reporter on this story: Amena H. Saiyid in Washington at

To contact the editors responsible for this story: Gregory Henderson at; Jean Fogarty at; Rob Tricchinelli at