Robot Sub Racing to Stop Oil Leak at Sunken Rig

Crews have been using a robot submarine to try to stop an oil leak nearly a mile below the surface of the Gulf of Mexico, but officials said late yesterday it would take at least another day before they knew whether the job was completed. It could take hours or it could take months to stop the 42,000-gallon-a-day oil leak at the site of the sunken oil rig off the Louisiana coast. For the second consecutive day, high waves prevented boats and equipment from going out to clean the spill. Airplanes sprayed chemicals to break up the oil.

The robot submarines are attempting to activate valves at the well head in hopes of cutting off the leak; if the effort fails, they'll have to start drilling again. The spill initially appeared to be easily manageable, but has turned into a more serious environmental problem after officials discovered the leak on Saturday. The spill is still about 70 miles from the mainland, but only about 30 miles from a chain of barrier islands known as the Chandeleurs, which are an important nesting ground for pelicans and other sea birds. (More oil rig stories.)