A barge carrying nearly 1 million gallons of thick, sticky oil collided with a ship in Galveston Bay Saturday, leaking an unknown amount of the fuel into the popular bird habitat as the peak of the migratory shorebird season was approaching.

Booms were brought in to try to contain the spill, which the Coast Guard said was reported at around 12:30 p.m. by the captain of the 585-foot ship, Summer Wind. Coast Guard Lt. j.g. Kristopher Kidd said the spill hadn't been contained as of 10 p.m., and that the collision was still being investigated.

The incident has led to a shutdown of the channel for ship traffic entering and exiting the Gulf of Mexico, a spokesman for the Galveston County Office of Emergency Management told Reuters.

The ship collided with a barge carrying 924,000 gallons of marine fuel oil, also known as special bunker, that was being towed by the vessel Miss Susan, the Coast Guard said. It didn't give an estimate of how much fuel had spilled into the bay, but there was a visible sheen of oil at the scene.

Officials believe only one of the barge's tanks was breached, but that tank had a capacity of 168,000 gallons.

"A large amount of that has been discharged," Kidd said. He said a plan was being developed to remove the remaining oil from the barge, but the removal had not begun.

The barge was resting on the bottom of the channel, with part of it submerged. He said boom was being set up in the water to protect environmentally-sensitive areas and that people would be working through the night with infrared cameras to locate and skim the oil.

The barge was being towed from Texas City to Bolivar at the time. The Coast Guard said that Kirby Inland Marine, which owns the tow vessel and barge, was working with it and the Texas General Land Office at the scene.

The Coast Guard said six crew members from the tow vessel were in stable condition, but it offered no details about their injuries.