BP has finished pumping cement into the top of its blown-out well in the Gulf of Mexico, retired Coast Guard Admiral Thad Allen said.
But Allen said he's not ready to declare the well dead just yet.
"I think we can all breathe a little easier regarding the potential that we'll have oil in the Gulf ever again," he said. "But we need to assure the people of the Gulf and the people of the United States that this thing is properly finished."
Allen said the cement should dry in about a day. The next step involves an 18,000-foot relief well that intersects with the old well just above the vast undersea reservoir that had been losing oil freely since the Deepwater Horizon rig exploded off Louisiana on April 20, killing 11 workers. It will be about a week before the relief well finishes drilling the last 100 feet under the sea floor into the broken well.
Cement will then be pumped into the broken well, hoping to seal for good the ruptured pipe that blew its top months ago. That process could take weeks to finish.
Progress on the so-called "static kill" procedure was another bright spot as the tide appeared to be turning in the months-long battle to contain the oil. A federal report this week indicated that only about a quarter of the spilled crude remains in the Gulf and is degrading quickly.
There's still oil in the Gulf or on its shores — nearly 53 million gallons of it, according to the report released Wednesday by the Interior Department and the National Oceanic and Atmospheric Administration. That's still nearly five times the size of the Exxon Valdez spill, which wreaked environmental havoc in Alaska in 1989.
But almost three-quarters of the nearly 207 million gallons of oil that leaked overall has been collected at the well by a temporary containment cap, been cleaned up or chemically dispersed, or naturally deteriorated, evaporated or dissolved, the report said.
The remaining oil, much of it below the surface, remains a threat to sea life and Gulf Coast marshes, NOAA Administrator Jane Lubchenco said. But the spill no longer threatens the Florida Keys or the East Coast, the report said.
Some outside experts have questioned the veracity of the report, with at least one top federal scientist warning that harmful effects could continue for years even with oil at the microscopic level.
In an interview with NPR's Melissa Block, Allen referred to the latest figures as just a "starting point."