A massive oil spill in the Gulf of Mexico neared wildlife refuges and seafood grounds along the Louisiana coast on Friday, as efforts redoubled to avert what could become one of the worst U.S. ecological disasters.

President Barack Obama pledged on Thursday to “use every single available resource” to contain the oil slick and the U.S. military ratcheted up operations.

The leak from a ruptured oil well on the ocean floor off the coast of the southern state is pouring out crude oil at a rate of up to 5,000 barrels (210,000 gallons or 955,000 liters) a day, according to the National Oceanic and Atmospheric Administration — five times more oil than previously thought.