SEARSPORT – With last week’s news that the state is negotiating with a company to lease Sears Island for construction of a $400 million to $500 million liquefied natural gas terminal, a debate about the safety of the fuel is sure to follow.

The debate already is raging in Harpswell, where a liquefied natural gas, or LNG, terminal is being proposed by ConocoPhillips Co. and Transcanada Pipelines Ltd. The companies want to build the terminal on town-owned land once used by the U.S. Navy for importing jet fuel.

The companies hoping to build the terminal – to be called Fairwinds – are offering the town annual lease payments of $8 million. Residents will give the proposal an up or down vote Jan. 27.

Observers of the LNG industry say it is likely that only one of the two projects considered in Maine will go forward.

Upgrades or new LNG terminals are being considered in Port Tupper, Nova Scotia; Saint John, New Brunswick; Fall River and Somerset, Mass.; and Providence, R.I.

LNG is new to Maine, but it is becoming the fossil-fuel of choice around the United States and the world. Natural gas is available to businesses and homes in most of the United States, but only recently became available in northern New England.

Maritimes & Northeast built a pipeline in 1999 linking the Sable Island gas fields off Nova Scotia to existing pipelines in Dracut, Mass.

Jack Cashman, commissioner of the state’s Department of Economic and Community Development, who is leading the negotiations with the unnamed company interested in building an LNG terminal on Sears Island, has said the Sable Island fields have not provided the amount of gas expected.

Natural gas supplies throughout the United States no longer are capable of meeting demand, especially as electrical power plants and other industrial users switch over to the cleaner-burning fuel.

To fill the gap, gas fields have been developed in Nigeria, Liberia, Trinidad, Algeria, Qatar and the United Arab Emirates.

By cooling natural gas to minus 260 degrees Fahrenheit, the fuel condenses into liquid and can be shipped in large quantities.

With the increasing availability of LNG, shipping terminals have been developed or are in the process of being built in Everett, Mass.; Cove Point, Md.; Savannah, Ga.; and Lake Charles, La. Large storage tanks are essential to the operation.

At the terminals, the LNG is returned to gas, and pumped through a pipe to users. The Fairwinds proposal calls for a pipeline linking the terminal with Westbrook.

The Sears Island terminal probably would be linked to the Maritimes & Northeast pipeline in Winterport, state officials have said.

Since the Sept. 11, 2001, terrorist attacks, LNG shipping and storage facilities now are seen as potential targets.

Boston’s U.S. Coast Guard Marine Safety Office oversees port safety at the Everett, Mass. LNG terminal.

Lt. Dean Jones, Coast Guard spokesman for the Boston Marine Safety Office, said Friday that Coast Guard crews board all incoming LNG ships and inspect the vessels for safety, reviewing fire extinguishing and operating systems. Coast Guard vessels then maintain a “security zone” around the LNG ships, which can be 800 to 1,000 feet long.

The Coast Guard stays with the LNG ships while they off-load. The Federal Energy Regulatory Commission oversees port-side security, along with state police, Jones said.

The Everett terminal has operated since the early 1970s, and Jones was not aware of any major spills.

LNG ships are double-hulled, he said, and are “extremely safe and extra-strong vessels.”

If the Fairwinds terminal is approved, the Coast Guard’s Marine Safety Office in Portland would oversee its operation, said Lt. Matt McCann, Coast Guard spokesman for the Portland Marine Safety Office.

For Fair Play for Harpswell, the group fighting the Fairwinds proposal, port safety is just one concern, but an important one, organizer Chris Duval said Sunday.

“Nobody wants these facilities,” Duval said, as shown by the opposition groups that have sprung up where LNG terminals have been proposed.

Duval conceded that the industry’s safety record over the past 20 years has been good, but he believes the huge amount of stored methane gas still poses a threat.

“It’s like playing Russian roulette,” he said.

An explosion of the amount of LNG to be stored in Harpswell would produce a blast equal to 50 times the energy of the atomic bomb dropped on Hiroshima, Japan, he said.

“Is it fair to ask the citizens of this area to take that risk?” Duval asked.

Peter Micciche, a spokesman for the Fairwinds proposal, said, however, that more people are killed each year by lightning than by natural-gas fires or explosions.

Key to understanding the probability of fire or explosion, he said, is that natural gas burns only when it is mixed in a ratio of 5 percent to 15 percent with air.

Micciche said he shows skeptics a videotape showing a scene of about 5,000 gallons of LNG in a pit, which firefighters try unsuccessfully to ignite. When LNG or natural gas leaks, it dissipates very quickly, he said.

“There’s nothing to contain the gas,” he said.