Emissions spew out of a large stack at the coal-fired Morgantown Generating Station on the Potomac River in Newburg, Md. Maryland is pushing back against proposals to scale back a cap on emissions from plants in the Northeast.

Maryland officials are resisting a push to deepen carbon-emission cuts as part of a regional agreement to reduce power-plant pollution.

The nine East Coast states that make up the Regional Greenhouse Gas Initiative are negotiating new terms for the pact, set to expire in 2020. Massachusetts has joined environmental advocates pushing for a cap on carbon emissions from power plants that would fall 5 percent a year for the next decade, or twice the current rate.

Maryland Secretary of the Environment Ben Grumbles said the proposal could result in higher power bills for Marylanders and harm the state’s economy. If adopted, he said, Maryland would consider pulling out of the regional pact for the first time since it formed in 2008.

“I’m sure every single state could agree if the caps are too stringent for that particular state . . . then those states would be very vocal in saying, ‘We can’t accept that,’ ” Grumbles said.

Maryland Secretary of the Environment Ben Grumbles, second from the right. (Katherine Frey)

The Regional Greenhouse Gas Initiative creates a local cap-and-trade system that limits how much plants can pollute, and holds auctions where energy producers bid against each other for rights to emit carbon. Proceeds from the auctions fund clean-energy initiatives aimed at combating climate change.

In addition to Maryland and Massachusetts, the pact includes Connecticut, Delaware, Maine, New Hampshire, New York, Rhode Island and Vermont. New Jersey pulled out of the pact in 2011.

The Boston Globe was the first to report that Maryland was reconsidering its role in the regional pact. Grumbles says leaving is a last resort, and called the greenhouse-gas reduction program a success that should be expanded with additional states.

Unlike other states in the agreement, Maryland is on the same power grid as coal-heavy states that never signed on to the initiative, including West Virginia, Pennsylvania and Kentucky. That means energy companies in Maryland are competing against producers in nearby states who aren’t abiding by the same restrictions on emissions and use cheaper, non-renewable energy sources.

Complicating matters further is the Obama administration’s Clean Power Plan, which would require each state to draw plans to shift away from fossil-fuel powered plants. The plan would reduce the pressure of intra-state competition, but it’s on hold pending a U.S. Supreme Court challenge and could be changed under the next president.

“While we are pushing for environmental leadership in the state . . . we want to reduce the risk of having other neighboring states being able to provide dirtier and cheaper energy to the citizens of Maryland,” said Grumbles, a member of Gov. Larry Hogan’s cabinet.

Officials in the administration of Massachusetts Gov. Charlie Baker (R) have indicated that they don’t want to derail the pact by going too far with emission cuts.

“We’re definitely not strong-arming anyone to do anything,” Energy Secretary Matthew Beaton told the Massachusetts State House News Service last week.

A spokesman for Beaton said the state is committed to reducing carbon emissions and power bills, but wouldn’t say if it would continue pushing for steeper cuts to carbon emissions.

But in Maryland, local environmental advocates are continuing to make that case. Scores of activists urged lower emissions at a meeting last week seeking feedback on the greenhouse-gas initiative at the Department of Environment offices in Baltimore.

“With the support of neighboring states, we hope Maryland steps up to the plate to help the region meet the goals it needs to create good-paying, clean-energy jobs and curb climate disruption,” said Johana Vicente, an organizer for the Maryland League of Conservation Voters.

Democratic lawmakers have also expressed support for 5 percent annual cuts in allowable emissions.

“We have to be sensible about [reductions] and we have to phase it over a period of time in order to be affordable, but it’s always preferable to be ambitious,” said Del. Kumar Barve (D-Montgomery), who chairs the House of Delegates committee that oversees environmental issues.

Carbon emissions from states in the pact have fallen dramatically, from 122 million tons in 2009 to 83 million tons in 2015.

The reduction is 16 percent greater than in states that haven’t joined the initiative, according to an analysis by the Acadia Center, which advocates for clean energy. The analysis also says electricity prices have decreased 3.4 percent on average for participating states, while rising elsewhere.

Industry observers say lower demand for energy during the economic downturn and the rise of natural gas, which results in lower carbon emissions than coal, also drove the decrease.

Hogan (R), in office since 2015, has a mixed record on the environment. He signed legislation this year that requires Maryland to reduce greenhouse-gas emissions 40 percent below 2006 levels by 2030, and forged a deal to reduce the amount of runoff from Eastern Shore chicken farms into the Chesapeake Bay watershed. Hogan’s office says this year’s budget includes a record $53 million for a state fund for restoring waterways.

But the governor irked environmentalists by vetoing legislation to require 25 percent of the state’s energy to come from renewable sources by 2020, and by rolling back some regulations meant to reduce pollution in the Chesapeake Bay.

Some advocates said Maryland’s reluctance to sign on to more ambitious carbon-emission cuts is an example of the Hogan administration’s resistance to major environmental initiatives.

“Massachusetts, with a Republican governor, is out front here in combating climate change,” said Mark Kresowik, a deputy regional director for the Sierra Club’s Beyond Coal campaign. “You certainly see some hostility from Governor Hogan to good programs that reduce pollution and advance clean energy.”

Hogan spokesman Doug Mayer dismissed such criticism as unfounded.

“Governor Hogan has a strong record of enacting key environmental reforms to improve Maryland’s air and water quality,” Mayer said. “Anyone who questions his commitment to preserving and improving Maryland’s environment and natural resources simply doesn’t know the facts.”