Lawyers for the U.S. Environmental Protection Agency on Dec. 18 attempted to refute arguments targeting the latest national standard for ground-level ozone pollution amid a legal challenge from environmental groups, industry interests and some mostly conservative states.
A three-judge panel for the U.S. Court of Appeals for the District of Columbia Circuit heard long-awaited oral arguments in a complex case that dates back to October 2015, when the EPA strengthened the National Ambient Air Quality Standards, or NAAQS, for ground-level ozone.
Ground level ozone, the main ingredient in smog, is formed when volatile organic compounds and nitrogen oxides emitted from sources such as power plants, industrial facilities and motor vehicles chemically react in the presence of sunlight. Elevated levels of ozone can cause or exacerbate breathing problems in children, outdoor workers and individuals with existing respiratory conditions. If certain areas within a state exceed the NAAQS, states are required under the Clean Air Act to submit cleanup plans to the EPA that can trigger the need for new sources of emissions to install additional pollution controls.
In revising the primary and secondary ozone standards to 70 parts per billion — down from the previous level of 75 ppb — in 2015, former EPA Administrator Gina McCarthy insisted that the science to support an even more stringent level was too uncertain.
Nevertheless, environmental groups including the Sierra Club and Earthjustice challenged the standard at the D.C. Circuit, arguing that the EPA dismissed advice from its Clean Air Scientific Advisory Committee and set the new level of acceptable ozone pollution too high to adequately protect sensitive populations.
While environmental groups argued that the 2015 ozone standard was too weak, coal mining company Murray Energy Corp. asserted that the rule was too stringent, as did a coalition of states led by Arizona. The challenges ultimately were consolidated, and the D.C. Circuit in April 2017 placed the litigation on hold to give the Trump administration time to review the 2015 ozone standard.
More than a year later, however, the EPA said it does not intend to revisit the standard, placing the agency at odds with Murray Energy CEO Bob Murray — one of President Donald Trump's biggest supporters. The court then lifted the abeyance, which led to the EPA defending the standard against multiple lines of attack during the Dec. 18 oral arguments in Murray Energy Corp. v. EPA (No. 15-1385).
Arguing on behalf of state petitioners, Arizona Solicitor General Dominic Draye asserted that the EPA in setting the new standard inappropriately focused on average, rather than peak, contributions of background ozone — ozone formed from natural sources such as wildfires. That presents a problem, he argued, because nonattainment is triggered by an area's fourth-worst eight-hour reading for ozone instead of its months-long average over the ozone season. Under the 2015 standard, areas within Intermountain West and upper Midwest states with background levels of ozone that account for 70%-80% of total levels will be unfairly subjected to onerous permitting requirements that can stifle economic growth, Draye said.
However, Judge Thomas Griffith challenged Draye by asking him whether the Clean Air Act requires the EPA to consider background ozone when establishing the NAAQS. In doing so, Griffith noted that the statute contains at least three provisions that allow the agency and states to account for background ozone from interstate and international transport when implementing the NAAQS. That "suggests that's where you pay attention to background ozone … that it's not necessary to do so when you're establishing the NAAQS in the first instance," he said.
In response, Draye contended that those provisions are evidence that Congress did not intend for states to be "on the hook for ozone that they can't control." He also argued that the D.C. Circuit and U.S. Supreme Court already have held that relying on "safety valves" to uphold arbitrary rules is illegal.
Judge Nina Pollard similarly expressed skepticism about the states' argument on background ozone. "The idea is that the dominant goal of the statute … is to set levels that protect the public health, and if it's really impractical, the agency is not allowed to say, 'Okay, let's harm a bunch of people because it would be really hard to move forward without allowing a lot more ozone,'" she said.
Justice Department attorney Simi Bhat said the states' arguments would deny protection to millions of Americans when the record shows that only a few areas would experience high background ozone events. Excluding California, 14 counties with air monitors are projected to measure ozone pollution above 70 ppb in 2025 — down from 213 counties with monitors that measure ozone above a level of 70 ppb based on 2012-2014 air quality data, according to an EPA fact sheet.
'Notable forward progress'
In contrast, Seth Johnson, an Earthjustice attorney representing environmental groups, said the EPA has failed to set a standard that adequately protects public health. Noting that the agency's own analysis found that an eight-hour level of ozone exposure at 72 ppb caused a majority of healthy young adults to suffer adverse health effects, Johnson said areas will be allowed to repeatedly register ozone levels at or above that level while still complying with the standard.
Judge Robert Wilkins pressed Johnson on that point.
"Are you saying that the [Clean Air Act] requires them to set the standard such that ... to be in compliance, the area can never exceed that standard on any given day?" he asked.
Johnson said the statute mandates that the agency set a standard that ensures the absence of adverse effects on sensitive subpopulations. "EPA hasn't done that here," he said.
In response, Justice Department attorney Justin Heminger asserted that the revised standard represents "notable forward progress." The EPA administrator lowered the standard "to protect the health and welfare of at-risk populations, particularly children and asthmatics across this country," Heminger said.