London (CNN) -- Environmental campaign group Greenpeace has warned that if oil leaks from the stricken cruise liner Costa Concordia it could cause an environmental disaster, threatening marine life including birds, whales and sharks. At least six people died when the huge ship hit rocks and slid onto its side. The vessel -- containing hundreds of tons of fuel oil -- is now partially submerged off the Italian island of Giglio, which lies inside the Pelagos Sanctuary for Mediterranean Marine Mammals. The sanctuary was set up 10 years ago in an agreement between France, Italy and Monaco, with about half of it existing in international waters.
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The Costa Concordia, which grounded off Giglio, contains more than 2,000 of tons of oil
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Giglio is in the Pelagos Sanctuary for Mediterranean Marine Mammals which was set up in 2002
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Greenpeace fears that there will be an environmental disaster if the oil leaks
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Costa Cruises has employed an expert salvage team to try to protect the sea
In a statement, @placeholder said: "We have engaged the services of a worldwide leader, a specialized salvage company to develop an action plan and help establish a protection perimeter around the ship."