Eight Northeastern states petitioned the Environmental Protection Agency on Monday to require a group of "upwind" Midwest and Southern states to more aggressively reduce smog-forming pollutants from power plants that drift across their borders and pose health risks.

The states, all represented by Democratic governors, said the petition was a last resort after trying to persuade the leaders of the upwind states — Kentucky, Illinois, Indiana, Michigan, North Carolina, Ohio, Tennessee, Virginia and West Virginia — to reduce harmful emissions that cause respiratory problems, such as asthma.

"We need the EPA's help to clean our air," said Delaware Gov. Jack Markell, who joined Connecticut, Maryland, Massachusetts, New Hampshire, New York, Rhode Island and Vermont in the petition. "There is virtually nothing left that we can do about it in our states."

The move comes one day before Supreme Court oral arguments on an Obama administration-proposed EPA rule to regulate ozone and fine particle emissions from upwind states.

The U.S. Court of Appeals for the District of Columbia Circuit rejected that proposal in August 2012, saying it didn't give states enough time to devise emissions reductions plans and could force individual states to do more than their fair share in curbing emissions.

The petition, however, is "complementary" to that federal rule, said Delaware Secretary of Natural Resources and Environmental Control Collin O'Mara.

Northeast officials stressed they have done all they can to slash emissions in their states. Much of the ozone air pollution — up to 98 percent — in those states come from the upwind Southern and Midwestern states, they said.

"We would largely eliminate the days that we are not within the federal Clean Air Standard" for ozone, said Connecticut Gov. Dannel Malloy.

Southern and Midwestern states would have to meet the same standards as Northeastern states if the EPA approves the new zone. That means electric utilities in those states would need to install pollution-control technologies to manage emissions, among other measures.

O'Mara said adding that technology would be less costly for those states than it was for the Northeast states, which implemented those upgrades before they were battle-tested and produced at a commercial scale. He estimated it would cost those states between $200 and $500 per ton of pollution, compared with the $10,000 it would cost Northeast states to do so today.

Frank O'Donnell, president of Clean Air Watch, said the petition could serve as a valuable pinch hitter for downwind states as the future of the federal rule remains uncertain.

"With a legal cloud hanging over that rule, this petition could provide much-needed relief for breathers in the affected states," O'Donnell said in an email.

The Northeast governors estimated bringing in their Midwestern and Southern counterparts would yield billions in health care and environmental savings throughout all the states involved.

"We are, in our eight states, the tailpipe to the emissions of upwind states, and it is having a significant impact" on health and environmental quality, said Vermont Gov. Peter Shumlin.