A drifting barge smashed into the 147,000-ton Hong Kong-registered supertanker Hebei Spirit on December 7 in the Yellow Sea, holing it in three places.

The single-hulled tanker spilt 12,547 kiloliters (10,900 tonnes) of crude oil into the Yellow Sea, some 20 percent more than the initial estimate, maritime authorities said.

Scores of fish farms and miles of beaches along a section of the west coast were fouled.

"Following the accident, we plan to advance the timetable to phase out singled-hulled vessels," Lee Ki-Sang, deputy director of the Ministry of Maritime Affairs and Fisheries, told AFP.

He said South Korea originally planned to phase out visits by those vessels by 2015 but it is now considering advancing the deadline by up to five years.

International efforts have been underway to require oil tankers to be double-hulled.

Such ships have some 1.2 meters (four feet) between the outer hull and fuel tanks to safeguard against leaks following a collision, said Bernd Bluhm, a representative from the European Maritime Safety Agency.

The European Union is seeking to close its waters to single-hulled tankers starting next year, he told a press conference held a fortnight after the spillage.

"But I don't think single-hulled tankers will disappear. They will sail in other areas, including Asia," Bluhm said.

Vladimir Sakharov, a representative from the United Nations Environment Programme, said experts from the UN and European Union had been impressed at the "spirit of solidarity" by thousands of South Koreans volunteers who joined the clean-up.

But Olof Linden, an oil spill expert working for the UN, warned that excessive clean-up operations would cause additional damage to the ecological system. He said Mother Nature should be given a chance to do the rest of the job.

Local environmentalists say it may be years before the coastline can fully recover, despite the daily efforts of tens of thousands of people and hundreds of ships battling the spill.

The European Union, the United Nations and Japan have despatched environmental experts to assist the cleanup. Aid has also come from Singapore, China and the United States.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.