MORGAN CITY, La. (AP) _ A 15-mile stretch of the Intracoastal Waterway was reopened Monday after being shut down for a week because of a spill of thousands of gallons of toxic styrene.

The Coast Guard reopened the vital water traffic artery near Morgan City during the morning, clearing a backup of about 100 vessels, many of which had been waiting for days.

Two barges, one carrying styrene and caustic soda and the other carrying limestone, collided Jan. 26, spilling 50,000 to 89,000 gallons of styrene, said Coast Guard Lt. Allen Harker.

Fumes from the styrene, a highly toxic and flammable chemical used to make plastic and rubber products, polluted the air. Some seamen were treated for nausea and headaches, but no serious injuries were reported, officials said.

Elsewhere in southern Louisiana, the Coast Guard said three weekend oil spills had released more than 10,000 gallons of oil in bays and lakes.

The EPA was cleaning up the smallest spill, a leak from an underground pipeline discovered Saturday. By Monday afternoon, it had been encircled by booms and vacuum trucks were being used to suck up the oil.

Private contractors were cleaning up a spill of as much as 4,200 gallons of oil that stretched for three miles, and a larger one of about 8,400 gallons that had washed ashore in Jefferson Parish.