Eastern states struggling to meet federal ozone limits may ask Pennsylvania to curb power plant pollution, as Maryland pushes for another chance to force its northern neighbor to do something about its dirty air.

Twelve states and the District of Columbia making up the Ozone Transport Commission delayed a June 11 vote on a petition from Maryland that asked Pennsylvania—over that state’s objections—to run controls for smog-forming pollution at its power plants.

“OTC tabled any action so state members can review and get more information,” Dave Foerter, the commission’s executive director, said in a June...