The cleanup of an unknown amount of thick, sticky oil that spilled into Galveston Bay blocked traffic Sunday between the Gulf of Mexico and one of the world's busiest petrochemical transportation waterways, affecting all vessels, even cruise ships. A barge carrying nearly a million gallons (3.8 million liters) of marine fuel oil collided with a ship Saturday afternoon, springing a leak. Officials believe only one of the barge's tanks - which holds 168,000 gallons (636,000 liters), was breached, though Coast Guard Petty Officer Andy Kendrick said Sunday it wasn't clear how much oil spilled. Crews were skimming oil out of the water and about 6.5 miles (10.5kilometers) of containment booms were being used to protect environmentally sensitive areas of the Houston ship channel, AP quoted Coast Guard as saying, and it expects the leftover oil to be removed from the damaged barge Sunday, after which it will be taken to a local shipyard to be assessed. The mouth of Houston ship channel, which is between Galveston Island and Bolivar Peninsula, is closed to all ships in either direction, Coast Guard Lt. Sam Danus said, noting that it is "communicating with the cruise ship companies." The area is home to popular bird habitats, especially during the approaching migratory shorebird season, but Kendrick said there have been no reports of wildlife being impacted.