SALVAGE TEAM REFLOATS TANKER OFF WELSH COAST.

Byline: Sarah Lyall The New York Times

An oil tanker that ran aground off the Welsh coast last week was finally set afloat again Wednesday night, but only after it spewed more than 65,000 tons of crude oil into one of Great Britain's most environmentally sensitive areas.

The amount of oil that the government says has already leaked from the tanker Sea Empress far exceeds the 38,000 tons spilled by the Exxon Valdez when it ran aground off the coast of Alaska in 1989. The oil has created a 25-mile slick that is beginning to wash up on the tiny islands on the Pembrokeshire coast that are home to much of the region's wildlife.

Several attempts to free the tanker, which ran aground in high tide at the port of Milford Haven Feb. 15, failed when the weather and sea proved more powerful than the salvage operations. Salvage experts, working in calmer conditions Wednesday night, used a flotilla of powerful tugboats that succeeded in buoying up the tanker and then pulling it clear from the rocks.

If Wednesday night's attempt had failed, officials warned, the already battered tanker might well have broken up completely, sending the remaining 65,000 tons of oil into the water and toward one of only two marine preserves in Britain. Even though the tanker was pulled away on Wednesday evening, it was still leaking oil. Officials said they planned to have the Sea Empress towed to a position where it would be stable enough to remove the remaining oil.

Although the Sea Empress has already lost much more oil than the Exxon Valdez, the end result may not be as serious, because the oil that leaked from the Exxon Valdez was thicker and the local tidal conditions meant that it remained concentrated for a longer period along the Alaskan coast. In the case of the Sea Empress, some of the oil is being diluted as tides pull it out to sea.

But environmentalists warned Wednesday that the damage already done might resonate in the area for two decades or more. Among the wildlife depending on the area for homes and food are dozens of species of sea birds, including guillemots, razorbills, cormorants, three kinds of hawks, and the manx shearwater, of which half the world's population nests on the islands off the Pembrokeshire coast. Most of the birds spend their winters out at sea, but flock to Skomer, Skokholm, and Grassholm islands in huge numbers in late March and early April to lay their eggs and raise their young.

Dyfed Wildlife Trust, a local conservation group, reported on Wednesday that washes of oil were beginning to reach Skomer island. "The lives of 500,000 migratory birds are now seriously at risk," said Judy Phillips, a spokesman for the trust, which operates Skomer's nature preserve. She blamed the government, charging that it had "failed to provide an adequate and rapid response" to what she called "an ecological disaster."

Birds and other sea creatures, including the gray seals common to the Welsh coast, can die if they swallow even a little oil, or if oil coats their feathers or fur.