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’s 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.

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 in 2011.

Grumbles says leaving the pact 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 have not signed on to the initiative, including West Virginia, Pennsylvania and Kentucky.