The clean-up of an unknown amount of thick, sticky oil that spilled into Galveston Bay has blocked traffic between the Gulf of Mexico and one of the world's busiest petrochemical transportation waterways, affecting all vessels, even cruise ships.
A barge carrying around 3.8 million litres of marine fuel oil collided with a ship on Saturday afternoon, springing a leak.
Officials believe only one of the barge's tanks - which holds 636,000 litres, was breached, although Coast Guards say it isn't clear how much oil has spilled.
Crews are skimming oil out of the water and about 10.5km of containment booms are being used to protect environmentally sensitive areas of the Houston ship channel, the Coast Guard said.
It expects the leftover oil to be removed from the damaged barge on Sunday, after which it will be taken to a local shipyard to be assessed.
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The mouth of the Houston ship channel, which is between Galveston Island and Bolivar Peninsula, is closed to all ships in either direction.
The area is home to popular bird habitats, especially during the approaching migratory shorebird season, but there have been no reports of wildlife being impacted.
