HOUSTON — The latest effort to plug a gushing underwater oil well in the Gulf of Mexico appeared to be working, officials and engineers said on Thursday morning, though definitive word on its success was still hours away.
At the same time, government experts said that the flow of oil from the well, which has been gushing since an explosion and fire wrecked a drilling rig in late April, was several times worse than the preliminary estimate by BP, the oil company responsible for the rig and the well.
And The Associated Press reported on Thursday that the head of the agency responsible for regulating offshore oil drilling had been dismissed.
BP began the well-plugging maneuver, known as a top kill, on Wednesday, amid hopes that injecting heavy drilling fluid deep into the well could stem the relentless flow of oil that has devastated commercial fishing in the Gulf, fouled miles of coastline and put the company and federal regulators at the center of a political firestorm.
BP warned that success was not guaranteed and that it could fail at any moment. But engineers and geologists following the effort said the likelihood of success grew with each passing hour.
“The operation is proceeding as we planned it,” said Tony Hayward, BP’s chief executive, in a statement Wednesday evening. “We will be continuing for at least another 24 hours.”