Italian officials have confirmed the presence of light fuel in the sea around the capsized Costa Concordia that appears to have come from machinery on the ship.

However, Coast Guard spokesman Cmdr. Cosimo Nicastro says there is no indication that any of the nearly half-million gallons of fuel oil has leaked from the ship's double-bottomed tanks.

Nicastro said Saturday that the leaked substance appears to be diesel, which is used in rescue boats or as lubricants on machinery. There are 185 tons of diesel and lubricants on board.

He described its presence in the sea as "very light, very superficial" and appearing to be under control.

Crews were removing oil-absorbing booms used to prevent environmental damage in case of a leak. Originally white, the booms were grayish.

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