Both sides at the hearing agreed, however, that ground-level ozone regulations imposed by the EPA in 2015 are in need of revision.

The revisions to the Clean Air Act lowered the standard for ozone levels from the 2008 level of 75 parts per billion to a new level of 70 ppb in 2015.

Critics said the change was unnecessary – noting that overall ozone levels had dropped by 30 percent since 1980 – as well as confusing for local governments, with the old and new standards both in place. It left governments in the position of “chasing the wrong rabbit,” in the words of one witness.

A report by the committee staff estimated that 241 counties that were compliant with the old standards could be noncompliant under the new ones. States were given until Oct. 1, 2016, to determine which counties were noncompliant, triggering tougher air quality standards.

The committee report said counties would continue to be noncompliant – even if actual ozone standards improved – until EPA approves a maintenance plan, “which can take years.”

The bill, if passed, would give states until 2024 to finalize a plan to meet the EPA’s 2015 standards.