Oil Corp announced yesterday that one of its 85,000-barrel crude oil tanks had spilled because of flooding.

The company said it was not yet known how much oil had spilled at the Meraux, Louisiana refinery, but said some of the oil had been contained in the refinery grounds.

Each oil tank was surrounded by a retaining wall to keep the oil back in case of a spill, but the walls were filled with floodwater at the time of the leak, according to Murphy.

Limited accessibility was hampering efforts by spill responders to assess the damage on-site, but the company said much of the area around the spill had already been evacuated.

This latest spill follows a report of up to four million barrels of oil spilling into a marsh and wildlife refuge 120km south of New Orleans, following an aerial sighting on the weekend.

The Louisiana Department of Environmental Quality said two oil storage tanks appeared to have spilled into a marsh between the Mississippi River and the Gulf of Mexico. Each tank contained two million barrels of oil.

Impassable road were preventing detailed inspection and clean-up efforts. There were no people living near the spill, but the swamp is an environmentaly senstive area.

In other news, the US Environmental Protection Agency has reported damage to an oil terminal along the border of Alabama and Mississippi that is leaking into surrounding waters.