The Prestige, sailing under a Bahamas flag, was holed during an Atlantic storm on November 13. Spain refused to take the stricken vessel to port and ordered it tugged out to sea, where it broke in two and sank on November 19.

About a third of its cargo of 77,000 tonnes of heavy fuel oil spilled into the sea and much of it has washed ashore in northern Spain, coating beaches, killing wildlife and putting fishermen out of work.

A two-month fishing ban in the northwest region of Galicia was partially lifted yesterday for the first time while the foul-smelling oil continued to encroach on beaches across the northern coast of Spain. French beaches have also been soiled.

Some 50,000 tonnes of the toxic oil rests at the bottom of the Atlantic inside the wreckage. Cracks in the hull have been plugged, putting a temporary halt to oil seepage.

The preliminary report was dated January 29 and released in Spain yesterday by the tanker owners' association Intertanko.

The report supported what Spanish opposition parties have been claiming from the start - that Spanish authorities exposed their coasts to grave danger by ordering the leaking tanker out into an Atlantic storm.

Spanish officials have defended their decision as the best of a poor set of options, noting that local port authorities refused to accept the tanker.

Officials of the best-equipped local port in La Coruna said they feared the ship could have sunk and caused a major disaster closer to shore.

Intertanko Managing Director Peter Swift said that was understandable given the lack of a comprehensive plan to deal with ships in distress.

STRUCTURAL FAILURE SUSPECTED

Swift, in an interview with Reuters, said it may never be known what initially caused the damage that led to the Prestige taking on water, but that industry experts strongly speculate some kind of structural failure in the 26-year-old vessel.

"There is still the possibility that it was struck by a container or by a very heavy wave that led to the failure. But the structure in the way of the ballast tank did fail. It flooded. The ship heeled over. It lost power because it tripped the boilers. The ship started drifting close to the shore and the rest of the sequence is known," Swift said.

Swift said Intertanko, an association of 245 tanker owners representing 2,050 tankers or 60 percent of the world tanker fleet, agreed with the report from the Bahamas.

"The vessel could have been saved," he said.