The U.S. official in charge of the government's response to the Gulf of Mexico oil spill has authorized BP to cement its ruptured oil well, which has gushed crude into the waters since an oil rig explosion in April.
But Retired Coast Guard Admiral Thad Allen said late Wednesday the implementation of this procedure will in no way delay completion of a relief well. That relief well is considered to be the permanent solution for sealing the broken well.
Earlier, crews were able to force down the oil with drilling mud in a procedure known as a "static kill."
Allen said at a White House briefing that the latest effort by BP to seal the well is working, and that there is high confidence no more oil will leak into the environment.
At the same briefing, National Oceanic and Atmospheric Administration chief Jane Lubchenco gave details of a government study released Wednesday indicating that about 75 percent of the oil spilled into the Gulf has been collected, burned off or broken down by natural forces.
However, Lubchenco said the environmental impact of the spill is likely to be felt for decades.
The NOAA administrator said the amount of oil released has already impacted shorelines and animals such as nesting birds. She said the spill took place during a time when fish such as blue fin tuna have been spawning. The effects on those fish may not be known for years.
Earlier in the day, President Barack Obama said he welcomed the news that the latest efforts to plug the well appear to be working. He said BP will continue to be held accountable.
U.S. scientists estimate that nearly 5 million barrels of oil leaked from the damaged well, making it the largest accidental release of oil into the sea in history. The leak has caused environmental and economic damage in the Gulf, angering residents and creating hardship for people who rely on the waters for their livelihoods.
BP is facing about $30 billion in cleanup costs.
