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EPA's New Ozone Standards Upheld

By Brett Snider, Esq. on December 12, 2013 | Last updated on March 21, 2019

The EPA's newest change to ozone standards was upheld by the D.C. Circuit on Tuesday, with both environmentalists and industry heads failing to convince the court to revoke the agency's rule.

In Mississippi v. EPA, the court reviewed the Environmental Protection Agency's (EPA) guidelines for the amount of ozone (O3) that is acceptable under the Clean Air Act. The EPA was being criticized for the standard being too low ... and too high, but the court found their judgment good enough for government work.

So, how much ozone is too much?

Change in Ozone NAAQS

Cases like this often look like alphabet soup, so let's take some time to break down at least one confusing acronym: NAAQS or National Ambient Air Quality Standards.

Each NAAQS is released by the EPA after considering changes in scientific data and findings on the risks of the particular compound to be regulated. In this case, the EPA changed its 1997 NAAQS for ozone (.08 parts per million) to the 2008 NAAQS (.075 parts per million). The D.C. Circuit had attempted to unseat the 1997 NAAQS as outside of Congress' authority, but they were overruled by SCOTUS.

Like with any Administrative Procedure Act case, the court only reviewed the EPA's discretion on this rule-making to determine if the change was arbitrary or capricious. And in this case, unlike that strange exception for biofuel, the court found that the EPA was fairly rational in setting the new levels.

Goldilocks and the O3

Part of what makes this kind of regulation so confusing is the ambiguity of the statutory obligations driving the EPA. The relevant code sections call for NAAQS for each air pollutant that both "allow[] an adequate margin of safety" and "are requisite to protect the public health.

Industry leaders and the state of Mississippi argued that .075 parts per million (ppm) was too low, and that there was not enough critical failure of the old standard to warrant this change. Meanwhile, the remaining petitioners argued that the ozone standard was too high, and based on the findings, it should have been closer to .06 ppm.

As the Mississippi v. EPA Court noted, "reasonable people might disagree" on the EPA's evaluation of the relevant new studies in choosing .075 ppm as the primary NAAQS for ozone. However, so long as the choice was rational and not capricious, assuming the EPA properly explained its process, then the D.C. Circuit was willing to defer to the EPA.

The only hitch that the court did find was an issue with the secondary NAAQS for ozone -- which was also .075 ppm. The D.C. Circuit has stated that these two cannot simply be identical and that the EPA must declare a separate standard which is "requisite to protect the public welfare."

Since the EPA didn't provide any separate reasoning for the secondary regulation, the court remanded it for "further explanation or reconsideration." But the D.C. Circuit left the final rule otherwise intact.

Bottom Line

Uncertain science is part and parcel of making environmental policy. So long as the EPA attempted to balance the data with risks to the public, a good estimate that makes many people unhappy is good enough.

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