New York Gov. George Pataki, a Republican, has worked since mid-2003 to include nine states in the Regional Greenhouse Gas Initiative. Massachusetts and Rhode Island dropped out of the plan this week.

Pataki's plan seeks to cut utility emissions of carbon dioxide. By 2020, emissions would be 10 percent lower than in 2000-2004.

Massachusetts Gov. Mitt Romney, also a Republican, refused to sign a memorandum of understanding on the pact, saying the agreement could boost prices for electricity in his state, which are among the nation's highest.

Neither Pataki nor Romney will seek reelection and both are thought to be aiming for the Republican nomination for the 2008 presidential election.

Rhode Island said more studies needed to be done on how cutting carbon emissions would affect prices for electricity.

While both Massachusetts and Rhode Island could come back to the program in the future, the number of states currently on board is seven.

Dale Bryk, an attorney at the Natural Resources Defense Council, who is advising the states, also said RGGI could be officially launched next week.

Connecticut's environment department said costs could eventually be offset because the plan would encourage utilities to become more efficient.

"Any impact on consumers would be fairly minimal and could eventually be offset by a focus on conservation and renewable sources of energy," Dennis Schain, a spokesman for Connecticut's Department of Environmental Protection, said in an interview. Studies for the states say the plan could boost costs to homeowners from $3 to $34 a year.

But business groups such as the New England Council and the American Council for Capital Formation said it would boost costs much more.

Even if an announcement comes soon, several states may still have to push the plan through their legislatures, which could lead to delays.

Environmentalists and carbon emissions brokers are anxious to see RGGI become operational because they hope it will link with similar plans being developed in western states and could be a model for a future federal plan.

US President George W. Bush, who favors voluntary caps on emissions over mandatory ones, withdrew from the Kyoto Protocol in 2001. The international pact set up a greenhouse gas market in the European Union and one in Canada that will launch next year.

Utilities such as Public Service Enterprise Group and KeySpan Corp. have supported RGGI, while Dominion Resources Inc. and NRG Energy have come out against it.

"Some companies believe that global warming is not going away and believe they can get competitive advantage by getting prepared (for a future national plan) through RGGI," said Bryk.