Updated 4 p.m.
A federal appeals court has vacated an EPA rule that would have limited the amount of power plant pollution that drifts across state lines. The impact of the ruling by the three-judge panel will be felt in Missouri.
The EPA passed the Cross-State Air Pollution Rule last summer.
It was intended to reduce soot and smog by capping power plant emissions of pollutants like sulfur dioxide that can drift over long distances.
Sierra Club Missouri Chapter Director John Hickey says cross-state rules are critical for reducing air pollution here in Missouri, and preventing health problems like asthma and heart attacks.
"Even if the state of Missouri were to effectively reduce air pollution from power plants located in the state of Missouri, that's not enough of that same pollution is blowing in from out of state, and we're breathing that in," Hickey said.
Hickey says now it's up to the EPA to decide whether to petition the appeals court for a rehearing, or to try to take the case before the Supreme Court.
You can see our original story on EPA’s approval of the Cross State Air Pollution rule, here.
Follow Véronique LaCapra on Twitter: @KWMUScience