The U.S. Coast Guard yesterday said it rejected an appeal of its decision to advise against a proposed liquefied natural gas terminal in Fall River.

The Coast Guard wrote a letter to Weaver’s Cove Energy LLC executives to reaffirm the agency’s position that the river approaching the project is unsafe for navigation by massive LNG tankers.

The latest decision follows a review of Weaver’s Cove’s appeal, which argued that the Coast Guard didn’t fairly evaluate all supporting information when it ruled that part of the transit route is a navigational hazard.

Weaver’s Cove spokesman Jim Grasso says the project is far from dead and the company will appeal again.

Roy A. Nash, the Coast Guard’s captain of the port for Southeastern New England, is expected to forward the appeal up the chain of command to the First Coast Guard District in Boston. The final appeal within the agency lies with the Coast Guard headquarters in Washington, D.C., he said.

In a decision announced in October, the Coast Guard concluded that allowing LNG tankers to travel through Mount Hope Bay and the Taunton River to a proposed terminal in Fall River would be too risky.

“After a careful analysis ... I find that the only reasonable conclusion is that the navigation safety risks associated with the vessels of the proposed dimensions and transit frequencies are unacceptably high,” Nash said at a news conference at the Coast Guard station at Woods Hole, Mass.

He said the area of most concern is the waterway from Prudence Island to the proposed site. That waterway, Nash wrote to the company, “is unsuitable from a navigational safety perspective for the type, size, and frequency of LNG marine traffic associated with your proposal.”

Weaver’s Cove Energy is owned by Hess LNG LLC, which is a joint venture owned equally by Poten & Partners and Amerada Hess Corp.

The company in 2003 first proposed building the LNG terminal. The project has been widely opposed by elected officials in Massachusetts and Rhode Island, as well as citizens groups and organizations in both states. Rhode Island was drawn into the debate because the tankers that would supply the terminal would traverse a 26-mile route through Mount Hope Bay. Opponents of the project say that the 725-foot LNG ships that would make up to 130 trips a year would disrupt other uses of Narragansett Bay and would create the risk of a disaster in the event of an accident or terrorist attack.

Despite that opposition, the Federal Energy Regulatory Commission, the federal agency that decides on permits for onshore LNG facilities, in 2005 gave the Weaver’s Cove proposal conditional approval.

Among the conditions was to gain additional approvals from several local and federal agencies, including the Coast Guard.

That agency first expressed concerns about LNG transits in March of last year, when Nash said that for tankers to safely pass through the old and new Brightman Street bridges over the Taunton River would require “extraordinary maneuvers.”

The bridges — the new one is still under construction — are only 1,100 feet apart, and their openings are not aligned, creating a navigational maze for large tankers.

Rep. Barney Frank and Rep. James McGovern, both Massachusetts Democrats, applauded the Coast Guard’s rejection of the appeal.

“While the company has the right to appeal the latest decision, I urge them to accept reality and finally put an end to this ill-advised proposal,” said Frank, in a statement.

McGovern said, “It is clear that the maritime safety issues involved in the proposed LNG terminal are significant. I hope the company makes a New Year’s resolution to pull the plug on this project.”