AUGUSTA — Environmental groups attacked Gov. Paul LePage on Monday for his refusal to sign a petition in favor of tough standards in nine states from which pollution affects air quality in Maine and other eastern states.

Governors in eight northeastern and mid-Atlantic states — including every New England state except Maine — have asked the U.S. Environmental Protection Agency to force states in the Midwest and South to reduce ozone-forming power plant emissions.

The petition comes before a U.S. Supreme Court hearing on the EPA’s 2011 Cross-State Air Pollution Rule, which is expected to begin on Tuesday. The rule would compel 27 states with coal pollution that blows across state lines into the eastern U.S. to limit soot and smog.

The Supreme Court is hearing the case after the U.S. Court of Appeals for the District of Columbia Circuit determined in August 2012 that the rule was invalid on multiple grounds. The challenge to the rule, which prevented it from being implemented, was brought by an alliance of industry groups and 15 states, in addition to several energy companies.

The petition in favor of the rule, which was signed by governors in the “Ozone Protection Zone” states of Connecticut, Delaware, Maryland, Massachusetts, New Hampshire, New York, Rhode Island and Vermont, calls for limits on the emissions of organic compounds and nitrogen oxides, which are known to cause asthma and other respiratory diseases. The states targeted by the petition are Illinois, Indiana, Kentucky, Michigan, North Carolina, Ohio, Tennessee, Virginia and West Virginia.

Jessamine Logan, spokeswoman for the Maine Department of Environmental Protection, said Maine joined two other Ozone Protection Zone states — Pennsylvania and New York, as well as Washington, D.C. — in abstaining from the petition, in part because Maine’s air is already clean enough to meet federal standards.

“Maine is in attainment with federal air standards and the largest source of impacts to Maine’s air is actually from mobile sources, not stationary ones,” wrote Logan in response to questions emailed to the LePage administration by the Bangor Daily News. “DEP has strong reasons to believe that future state and federal pollution requirements will mean further overall emission reductions from mobile and stationary sources, and that the state will continue to meet the federal air standards.”

The impending air-friendly requirements, according to Logan, include measures that will reduce the use of pollution-causing materials in fuels and motor vehicles, the increased use of natural gas and more stringent emissions requirements for power plants.

“Expanding the Ozone Transport Region would have very little benefit on the quality of Maine’s air, and we are working cooperatively with regional groups on reducing emissions from mobile sources, the largest source of emissions in Maine,” wrote Logan.

Environmental groups attacked LePage for not signing the petition. Glen Brand, director of Sierra Club Maine, said LePage’s refusal to sign the petition “fails to protect the health of Maine families.” Sierra Club Maine recently endorsed LePage’s Democratic opponent, Mike Michaud, in next year’s gubernatorial election.

“Maine needs a leader who will work with and support the region’s efforts to reduce harmful pollution that is causing serious health problems including asthma attacks and numerous other incidences of respiratory and pulmonary disease … At least half of the harmful smog and air pollution associated with coal plants originates from out of state,” said Brand in a written statement.

Dylan Voorhees, clean energy director for the Natural Resources Council of Maine, said his organization’s excitement when the rules were implemented in 2011 has been dampened by the court challenges. He said that input from governors could affect the Supreme Court’s decision.

“It’s disappointing that Maine has not signed on because we have so much to gain in terms of our air quality,” said Voorhees. “It’s important to the courts what the opinions of the states are. It’s also not an unreasonable expectation that Mainers have that their elected officials use their voices occasionally in matters like this that are really important. Having clean and healthy air should be a priority.”

Allison Martin, a spokeswoman for Kentucky Attorney General Jack Conway, told Reuters on Monday that power plant emission levels are partially caused by eastern states’ appetite for electricity.

“It’s a case of supply and demand,” said Martin. “The Northeast states have a tremendous demand for power and Kentucky helps supply the need.”