PORTLAND, Maine -- Up to five tankers a day unload heating fuel and gasoline at Maine's port city, making it the second biggest fuel transfer point on the east coast after Philadelphia.

Since, in a worst-case situation, a computer malfunction could result in an oil spill, port officials are concerned that all computer systems on tankers serving Portland are Y2K-compliant, and they are keeping a weather eye on three critical Y2K dates: Sept. 9, 1999; Jan. 1, 2000; and Feb. 29, 2000, or leap year day -- numeric dates that may confound older computer programs that have not been modified.

The port has just received some regulatory muscle from the U.S. Coast Guard, which recently issued a nationwide Y2K regulation requiring owners and operators of certain marine vessels and facilities, such as ships carrying hazardous substances like oil, to report on the state of their Y2K preparedness, or pay a $25,000-per-day fine.

'It is designed to put vessel owners on notice,' said John Cameron, executive officer for the Coast Guard Marine Safety Office in Portland, which oversees eight ports in Maine and New Hampshire.

The Y2K regulation will help the Coast Guard identify Y2K problems on vessels that could cause engines to stop, steering to malfunction and navigation equipment to go on the blink, 'Vessels that have a potential for Y2K failure are well out in front of being compliant,' Cameron remarked.

At the port in Portland, a level of safety measures has always been in place.