The Coast Guard says it has reopened the Houston Ship Channel to some traffic after thousands of gallons of oil spilled from a barge this weekend.

Officials said Tuesday that the key waterway on the Gulf of Mexico had been cleared enough to allow barges in and out, though cleanup continues.

As much as 170,000 gallons of oil spilled into one of the world's busiest waterways for moving oil on Saturday, when a barge carrying the oil collided with a ship.

The area is also a key sanctuary for birds and other wildlife.

State officials believe most of the oil is moving away from the coast near Houston and into the Gulf of Mexico. They hope the slick will wash up as "tar balls" farther south.