BANGOR – Maine businesses have been put on alert: Their shipments – whether incoming or outgoing – may be susceptible to terrorist attacks.

And business owners, as citizens of Maine, have been notified that explosive-laden cargo may travel through the state en route to its intended target. There, whether it’s a city or a national landmark, it could be detonated.

Experts from a national aviation research firm, the Federal Bureau of Investigation and U.S. Customs on Wednesday came to Maine Trade Day, sponsored by Maine International Trade Center, with a message that international trade is vital to the survival of the country, but it’s vulnerable to terrorists.

It would take just one package containing explosives strategically placed either in an aircraft’s belly or in a cargo container transported by ship and then by truck to go off and the world’s economy is crippled, said Michael Boyd, co-founder of The Boyd Group/Aviation Research Corp., based in Colorado.

“One cargo event and down goes our economy,” he said.

Very little is being done by the federal government – and not fast enough – to protect freight systems from being the next vehicles for destruction, Boyd said.

Since the attacks of Sept. 11, the federal government has been reacting by filling gaps in security, such as the screening of passengers going aboard airplanes to take away anything metallic that can be used as a weapon, he said.

Using a map of JFK Airport near New York City, Boyd pointed to areas that could be targets for terrorists not just at this airport but at every facility nationwide. Security isn’t as tight in areas that include cargo facilities, postal facilities, parking lots, roadways, fuel storage containers, fuel pipelines and electrical services such as air-conditioning units, he said.

“All have security systems, but do they interact and do they work?” Boyd asked. “A few carefully targeted areas and you could shut [an] airport down.”

He suggested that the federal government come up with every possible terrorism scenario, and then identify likely targets and come up with plans to deter threats.

At U.S. Customs, those measures are under way, said Philip W. Spayd, director of field operations for the U.S. Customs Service’s North Atlantic Customs Management Center in Boston.

Customs now has agents in Canada’s three major ports – Vancouver, Montreal and Halifax – and in conjunction with the Canadian government is developing ways to make security a priority before freight reaches the U.S.-Canada border.

Programs being developed include prescreening cargo and prequalifying businesses shipping the goods.

Without reliable and effective methods to securely lock cargo containers and then keep track of them, the scenario of one container rigged as a bomb leaving Europe by ship, entering Canada to be unloaded onto a truck, and driven through Maine to Boston, where it is detonated, could become real.

“If this were to happen,” Spayd said, “it would have a devastating impact on the economy.”

Maine businesses, which exported $1.8 billion in goods to 158 countries in 2001, were instructed to develop good freight security and tracking systems with their trade partners. Spayd urged the businesses not to just make sure they are in compliance with federal shipping standards, but to spend the extra money to ensure that they are terrorist proof.

“In the area of trade, Washington doesn’t have a plan,” said John L. Champagne, northeast regional director of Global Technology Network. “You need to have a plan.”

“You can’t look to government for solutions,” Spayd said. “This is a fight we’re all in.”

Canada is fighting, too, said Peter Forbes, who attended the event as a representative for the government of New Brunswick. Forbes, upset that Canada may be looked at as the back door for terrorists to enter the United States, said the neighbors to the north are just as concerned about future attacks as Americans.

Forbes told the audience that Canadians were firmly in the U.S. camp.

“We’re standing right beside you,” he said.