BOSTON — Talks broke down Wednesday among state officials trying to reach an agreement to reduce carbon dioxide emissions in the Northeast.

A spokesman for Rhode Island Gov. Don Carcieri said Rhode Island, Massachusetts and Connecticut had misgivings over the proposed nine-state plan to cut so-called greenhouse gases that contribute to global warming.

Carcieri is concerned about the costs, according to spokesman Jeff Neal. "Ultimately we don't know how much this plan will raise energy prices," Neal said.

A spokeswoman for Massachusetts Gov. Mitt Romney said he would likely comment on the matter on Thursday. Romney has expressed concerns with the initiative in the past, saying the costs of cutting emissions would be passed on to consumers.

A message left with Connecticut Gov. M. Jodi Rell's chief of staff was not immediately returned.

The bipartisan Regional Greenhouse Gas Initiative has been working since 2003 on what would be the first multistate program in the nation to reduce emissions of carbon dioxide. The states involved are New Jersey, Delaware, New York and the six New England states.

The draft proposal would freeze utility emissions at current levels through 2015, and then require a 10 percent reduction by 2020. It also would create a market for greenhouse gases, allowing those who lower emissions to sell excess "credits" to those who can't cut quickly enough.

Some critics fear the plan could drastically increase electricity rates because it would force companies to build new plants, or convert plants to use natural gas.

Peter Constantakes, a spokesman for New York Gov. George Pataki, said the remaining states would try to go forward.

Environmental groups were disappointed that the states couldn't reach an agreement.

"It's very disappointing, but we're hopeful it will proceed," said Seth Kaplan, senior attorney for the Conservation Law Foundation in Boston.

Source: Associated Press