Scientists from BP and the federal government are reviewing the results of testing that could determine whether the leaking Gulf of Mexico oil well has been plugged for good.

BP said in a news release Friday that the testing was completed Thursday night. Officials expect to make a recommendation to retired Coast Guard Adm. Thad Allen soon. Allen is the government's point man for the spill response.

For weeks, officials have said the only way to permanently seal the well is to pump in mud and cement from below the leak. But now, they suspect that might have already happened when mud and cement was pumped in from above earlier this month.

If the tests show more work needs to be done, it would take four days to get crews back in position to resume the operation.

(This version CORRECTS that mud and cement was pumped in from above this month, not last month.)