New Orleans, Louisiana (CNN) -- Three weeks after BP plugged its crippled Macondo oil well in the Gulf of Mexico with cement and mud from above, crews are "fishing" for pieces of drill pipe that need to be removed from inside the well's blowout preventer before crews can move on to the "bottom kill" -- the permanent fix for the well.
Once those pieces of drill pipe are retrieved, crews will be able to replace the Macondo well's old blowout preventer with a new one awaiting use on the nearby ship, the Development Driller II, BP spokeswoman Catherine Hill confirmed Thursday.
Meanwhile, Florida Gov. Charlie Crist on Thursday discontinued a state of emergency for the Keys (Monroe County) and 18 other peninsula coastal counties threatened by the spill. Seven Panhandle counties -- Escambia, Santa Rosa, Okaloosa, Walton, Bay, Gulf and Franklin -- are to remain under an extended state of emergency in order to qualify for economic aid, Crist's office said in a statement.
Thad Allen, the man in charge of the government response to the Gulf oil crisis, said Wednesday that the "fishing" operations had been delayed by a buildup of hydrates -- chemicals that form at low temperatures and high pressures toward the sea floor -- that temporarily jammed the cap that trapped oil in the well starting on July 15. Crews flushed the system to loosen the cap and began "fishing" through the top of the well again.
BP definitely plans to remove at least two smaller, cut pieces of pipe, but the status of a third, longer piece of drill pipe is unclear -- and that will affect how crews proceed, Allen said.
He added that they are trying to determine if the third piece was affected by the cement poured into the top of the well during the "static kill," process at the beginning of August -- and if so, how.
Crews are trying to determine what to do if they can't retrieve the third piece of pipe. They may have to try to remove the old blowout prevent with the third piece of drill pipe still attached, Allen said.
The retired Coast Guard admiral said Wednesday he is "hesitant" to give out any timeline for the process until they figure out the condition of the third piece of drill pipe.
Crews need to replace the blowout preventer to ensure that the pressure inside the Macondo well will remain at a safe level when they intercept the Macondo well through a relief well at nearly 18,000 feet deep.
"Our first goal is to do no harm," Allen said in a teleconference last week.
Investigators also want to examine the original blowout preventer, which did not work properly to choke off the well as it should have.
Once the new blowout preventer is in place and Allen gives crews the green light to resume drilling, it will take them about four days to prepare, drill the final 50 feet of a relief well and intercept the main well. Then, the "bottom kill" process of plugging the well from below will begin. Allen has said cementing will require another several days.
The environmental disaster began after an April 20 explosion on the offshore drilling platform Deepwater Horizon that killed 11 men. Two days later, the platform sank and oil from the Macondo well underwater started gushing into the Gulf.
Investigators don't want the drill pipe to damage the blowout preventer because they want to see it "as is" to determine the blowout preventer's role in the calamity.
The government says 205.8 million gallons of oil escaped from the well before it was sealed on July 15.
Even though oil has not flowed from the well site since July 15, seven Panhandle counties including Escambia, Santa Rosa, Okaloosa, Walton, Bay, Gulf and Franklin are to remain under an extended state of emergency in order to qualify for economic aid under state and federal disaster guidelines.
There have been no reported physical oil impacts to the Keys from the April 20 Transocean/BP explosion and subsequent spill, according to Captain Pat DeQuattro, sector Coast Guard Key West sector commander
CNN's Vivian Kuo contributed to this report