DC Circuit Looks Askance at Conservationist Challenge to Weakening of Smog Rule

WASHINGTON (CN) — Conservationists warned the D.C. Circuit on Tuesday that the Environmental Protection Agency under President Donald Trump applied a new regulatory scheme that lets states game requirements meant to reduce overall emissions of ozone-forming pollution. 

Whereas the Clean Air Act requires states to demonstrate that they have met emissions-reduction milestones, the EPA adopted a new standard in 2018 allowing states to simply show that they have implemented measures previously predicted to reduce ground-level ozone, a component of smog.  

The Sierra Club mounted a challenge, claiming that the shift would contravene congressional intent as lawmakers had tightened regulations two decades prior. 

“Overall when Congress amended the Clean Air Act in 1990, it did so in order to curb flexibility,” Earthjustice attorney Seth L. Johnson said Tuesday, representing the Sierra Club and other challengers at oral arguments in Washington. 

But the argument quickly met with resistance from the three-judge panel.

“To permit flexibility within a range of reasonable options is foreclosed by the statute?” asked U.S. Circuit Judge Gregory Katsas, a Trump appointee.

“It can’t be EPA’s fundamental basis for allowing it,” Johnson replied. 

U.S. Circuit Judge Harry Edwards in turn said that it was hard to conclude the agency had acted arbitrarily and capriciously on those grounds. 

“The difficulty with your argument is if you concede that both choices are reasonable, that’s a bad starting point,” the Carter appointee said. 

Buckling down on the Clean Air Act provision under review, Johnson said Congress made clear that choosing baseline years falls on Washington, not state regulators. 

“EPA can pick either one, but EPA has to pick,” the attorney said. 

But the government argued the EPA administrator — former coal lobbyist Andrew Wheeler has held the title since 2018 — can opt not to enforce some regulatory requirements if doing so results in better air quality. 

Justice Department attorney Perry M. Rosen argued that Congress recognized “interprecursor trading” can be beneficial, while the Sierra Club argued it amounts to a regulatory loophole barred by the Clean Air Act.

“It’s allowed because the science clearly supports it. There is no linear approach to reducing ozone through the reductions precursors,” Rosen said. 

Under interprecursor trading, states can rely on computer simulations to estimate what reduction in an ozone-former pollutant is necessary based on a reduction of another such pollutant, rather than presenting hard data. 

U.S. Circuit Judge David Tatel, a Clinton appointee, questioned how EPA can accept reported reductions in emissions without proof in numbers.

But Rosen argued that the actual data on the success of emissions reduction measures “may be stale by the time you make that determination.” Because the reports are triennial, he added, the data may not reflect advances made in the last two year.

On rebuttal, the Sierra Club said the EPA was arguing policy not the law and could not override the congressional requirement for states to prove that predicted reductions materialized. 

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