MOBILE, Ala. -- Officials at one of the nation's busiest ports are hoping that a simple wash-and-go system will keep out the oil from the spill in the Gulf of Mexico.
Floating balls of tar already are showing up at the mouth of Mobile Bay.
So authorities are setting up makeshift locks to scrub incoming ships.
Mobile is the nation's ninth-busiest port by volume. It's also the second-biggest on the northern Gulf Coast.
Experts say Mobile is more vulnerable than New Orleans since it sits close to the Gulf atop a shallow bay.
The Crescent City is 120 miles up the Mississippi River.