PORTLAND (AP) – Coast Guard inspectors on Thursday were prepared to stop all international vessels stopping, as part of a new national security code aimed at shoring up security at the nation’s ports.

The International Ship and Port Facility Security Code requires port facilities, chandleries and owners of ships larger than 500 tons to draw up detailed plans for responding to a terrorist threat.

The treaty, signed by 147 governments, is the shipping industry’s biggest anti-terrorist effort so far.

Failure to comply could lead to time-consuming inspections of ships that don’t meet the new standards. And ships bound for the United States from ports that don’t comply with the code could be searched or ordered back to sea.

In Portland, Coast Guard inspectors on Thursday planned to board the SKS Sinni to ensure the oil tanker from the Marshall Islands has anti-terrorism security plans aboard. The tanker carries Canadian-bound crude oil to a Portland pipeline.

“The impact for the average citizen is the security and knowledge that steps are being taken to improve port security,” said Lt. Chris O’Neil, governmental affairs officer for the Coast Guard in Boston.

All of the terminals and facilities in Portland Harbor, as well as ships based there, have had security plans approved by the Coast Guard, said Lt. Matt McCann, the Coast Guard’s chief of port operations for Maine and New Hampshire.

About 300 foreign-flagged ships make trips to Portland each year, but many are periodic trips by the same vessels, which do not need their security plan checked every time they enter a U.S. ports, McCann said.

Most vessels will be met at sea before they enter port. Portland Transportation Director Jeff Monroe said the new requirement could lead to delays for some shippers if their paperwork was not in order.

Besides security stops, security cameras and restricted access at the Casco Bay Ferry Lines terminal have been in place since the beginning of the summer season.

Joe Cox, president of the Chamber of Shipping of America, which represents U.S. ship owners, said he expects strict enforcement of the regulations.

“I don’t think there’s a ship around here dumb enough to come into U.S. waters without the certificate,” he said.

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