It's unlikely that engineers will be able to stem the flow of oil into the Gulf of Mexico until August, Sen. Bill Nelson (D-Fla.) suggested Thursday.

Nelson, whose home state of Florida is preparing for oil to reach the beaches of Pensacola, said he has no faith in BP's efforts to end the flow of oil from its damaged deepwater well until relief wells are completed in August.

"Personally, I don't," Nelson said during an appearance on CNN when asked if he has any faith in BP to contain the flow of oil. "I think we're looking at this until August."

BP's latest effort involves an attempt to cut the oil pipeline to more cleanly fit a temporary cap over the leak, a temporary fix until the relief wells can be finished, which is estimated to happen in August. Efforts to use a diamond saw to cut the pipeline were suspended on Wednesday evening, and now the company is using giant "cutters" to cut the pipeline.

That effort came after the "top kill" procedure, using mud and cement to try to plug the pipeline, failed last week.

Nelson said that if the crisis goes unresolved until August, the magnitude of the spill would dwarf the Exxon-Valdez incident.

The Florida senator wrote President Barack Obama this week to formally request that the president authorize a military takeover of the efforts. Nelson said the Defense Department was best suited to deploy the massive amounts of skimmers and booms needed to prevent oil from coming onshore in Florida, Louisiana and elsewhere.

"What I'm saying is, if you're looking at this all the way to August, and maybe beyond, we better get ready because it is now bearing down on our beaches, and that's where I'm going today," Nelson said.