An enormous oil slick advanced toward one of Europe's busiest fishing regions today as sailors and fishermen raced to intercept it with floating barriers and oil-skimming boats.

The giant, multimillion-gallon sheen bobbed in the waves off the northwest Galician coast. Residents of the region have been mopping up their beaches and rocky coastline for the past two weeks since the first slick from the tanker Prestige washed ashore.

Under cloudy skies today, hundreds of volunteers in protective white jumpsuits, masks and gloves continued shoveling oil-soaked, mucky sand into plastic-lined buckets to be hauled away. The masks and gloves shielded skin and lungs from the sulfur in the fuel oil.

Offshore, half a dozen boats skimmed oil from the ocean, while maritime officials and fishermen deployed more floating, orange barriers between the advancing pollution and the coast. The slick contained about 2.4 million gallons of toxic fuel oil.

Spaniards viewing the slick through binoculars steeled themselves for the "black tide" they have dreaded since a crack opened in the tanker's hull during a storm on Nov. 13. The Prestige was carrying about 20 million gallons, and about 4 million gallons seeped out.

"It's a disaster, just a disaster," fisherman Jose Ramon Montero, 26, said at the Cape Fisterra lighthouse while looking out at the Atlantic.

The slicks from the Prestige, which ruptured near Cape Fisterra, have prompted the government to ban fishing and shellfish harvesting -- the region's staple industry -- along a 310-mile stretch of coast. The initial damage was estimated to be $42 million.

Officials estimated the Prestige spilled 1.6 million gallons when its hull cracked and at least the same amount again as it drifted offshore seeking permission to enter a Spanish port to offload its cargo. Permission was denied and the tanker split in two and sank Nov. 19 about 150 miles off Cape Fisterra.

Environmentalists claim the tanker actually leaked some 5.3 million gallons.

Seven anti-pollution boats from Spain, France, the Netherlands and Britain have skimmed about 800,000 gallons of oil from the sea.

The government of Prime Minister Jose Maria Aznar has maintained that the oil that sank with the Prestige would solidify in the chilling cold and high pressure of the deep sea.

However, the wreck continues leaking oil from its resting place 2.2 miles down on the ocean floor. Signs of fresh oil coming from the sunken tanker were detected by French and Portuguese reconnaissance planes, but Spain has said the oil is from the ship's own fuel and lubricant.