A slick caused by Israel's bombardment of a power plant in Jiyyeh last month, dumping 15,000 tons of fuel oil that has spewed a black tide along a 87-mile stretch of the coastline.

Few places have been hit harder than Byblos, which dates back 7,000 years and lies 22 miles north of Beirut.

Thick black oil laps against the ancient stone wall of the harbor under the shadow of a 13th century watchtower. Workers use a mechanical digger to scoop it from the water and dump it into plastic tanks on the quayside.

From here it is taken to Beirut to be mixed with gravel and stone to make building material. Much of it will be used to patch up roads blown apart by Israeli bombs during the war, which ended with a United Nations-backed truce on August 14.

"Since we started, we've dredged over 100 tons of oil from these waters," said Nabil Saad of the Byblos town council. "We still have several more days' work to do."

A mile down the coast, around 100 volunteers are shoveling blackened sand from once-white beaches.

Israeli strikes on fuel storage tanks at the Jiyyeh power plant south of Beirut on July 13 and 15 led to a leaching of an estimated 10,000-15,000 tons of heavy fuel oil into the Mediterranean Sea, according to U.N. and Lebanese estimates.

Environmentalists say the slick could harm dolphins, Bluefin tuna fish and loggerhead turtles.

Baby turtles hatch on the Lebanese coast each summer and then crawl toward the sea. Campaigners fear that when they get there, some will die in the deadly black tide.

Marine Life Threatened

"The scene is horrific, the seabed is completely covered with fuel oil which will threaten marine life for many years to come if it is not contained and removed immediately" said Mohammed El-Sarji, Greenpeace activist and head of the Lebanese Union of Professional Divers who conducted several dives in Jiyyeh.

The Israeli air and sea blockade of Lebanon, imposed at the start of the 34-day conflict, significantly complicated the clean-up operation, making it impossible to assess the slick.

This week, Israel finally granted U.N. environmental experts permission for an aerial survey of the spill, described by Lebanese Environment Minister Yacoub Sarraf as the biggest environmental catastrophe in Lebanon's history.

Cleanup of a massive oil spill caused by Israeli air strikes on a fuel depot could take up to one year, the environmental group Greenpeace Mediterranean said

The United Nations Environmental Program (UNEP) has compared it to a 1999 disaster off France when the tanker Erika spilled an estimated 13,000 tons of oil into the sea.

"We think it's around 15,000 tons which is a big spill by global standards," said Professor Rick Steiner of the University of Alaska, who is advising the Lebanese government on the spill.

Steiner, who has worked on some of the world's worst oil slicks including the 1989 Exxon Valdez disaster in Alaska, told reporters this was one of the worst he had seen.

"I was down on the coast here in Beirut this week," Steiner said. "Everything on it -- limpets, invertebrate fauna, algae, fish, crabs, mussels -- it was all dead."

Complicating the clean-up is the fact that the spill is heavy fuel oil.

"It moves in different ways from crude oil, it's thicker and it doesn't evaporate as easily," Steiner said. "This might the first time ever that seabed contamination has been documented this clearly. The oil is extensive and very toxic and we need to find a way to save the marine environment."

The spillage has spread as far north as Syria and, according to some environmentalists, has even reached eastern Turkey.

After Israel gave permission, UNEP said surveillance flights should be carried out as swiftly as possible. The United Nations has agreed an action plan to deal with the spill but says it needs to raise 50 million euros ($64.18 million) to pay for it.

Blow to Tourism

In Byblos, once a Phoenician port and one of the busiest trading posts in the eastern Mediterranean, the slick has helped decimate a tourist industry already hit by war. Beachside cafes and hotels are empty. Lounge chairs lie unused next to oily waters.

Thirty miles further north, on an island nature reserve off the coast, environmentalists have raked the sand clean in a bid to save turtles due to hatch any day now.

"There are 16 turtle nests at the reserve," said Manal Nader, director of the institute of the environment at Balamand University in northern Lebanon. "We're hoping that our action means they will survive."

Some Lebanese environmentalists say Israel should pay for the clean-up operation, although few believe this will happen.

In the meantime, the inhabitants of Byblos struggle to clean up the mess.

"The place got hammered," Steiner said. "To see this Phoenician harbor, this important archeological site covered in toxic oil, it really is heartbreaking."

Photos of the environmental tragedy

Sources: Reuters, Washington Post, Greenpeace