BP started a “top kill” procedure Wednesday afternoon in an attempt to stop oil from gushing into the Gulf of Mexico, the company said.

At 1 p.m. CT (2 p.m. ET), the oil giant began pumping 50,000 pounds of thick, viscous fluid twice the density of water into the site of the leak to stop the oil flow, it said. If all goes according to plan, the well then could be sealed shut with cement.

BP Chief Executive Officer Tony Hayward said earlier the procedure has a 60 percent to 70 percent chance of succeeding.

BP conducted hours of diagnostic testing before starting, and Coast Guard Rear Adm. Mary Landry, the federal on-scene coordinator for the oil spill response effort, granted the final authorization for the company to move forward with the much-awaited operation.

President Obama, however, said his administration is exploring all options.

“If it’s successful, and there are no guarantees, it should greatly reduce or eliminate the flow of oil now streaming into the Gulf from the seafloor,” Obama said after discussing the top kill procedure with Energy Secretary Steven Chu.

“And if it’s not, there are other approaches that may be viable.”

Obama plans to announce Thursday strengthened inspections and an effort to tighten safety regulations for offshore drilling, an administration official said.

He also is expected to discuss other recommendations of a 30-day review that he ordered shortly after the oil leak began in late April.

The top kill procedure has worked successfully on above-ground oil wells in the Middle East but has never been tried a mile beneath the ocean’s surface. Other attempts by BP to stop the oil flow have failed.

If BP does not succeed, pressure for the White House to take action is sure to increase.

“If this thing doesn’t work, then the president ought to turn this over to the military,” Sen. Bill Nelson, a Democrat from Florida, told CNN. “You’ve got to have BP’s cooperation because they have the best technical instruments, but we have got to have somebody in charge and I think the U.S. military is best suited to do that.”

Grand Isle, Louisiana, Mayor David Camardelle said patience was wearing thin.

“I want the president to step in and make things happen,” Camardelle said. “We’ve been frustrated for the last 37 days, and we’re trying to get things moving the right way and our people can’t wait.”

Administration officials have insisted that BP is best equipped to plug the leak. Obama, who is planning to visit the Gulf Coast on Friday, said a lot of damage has been done already.

“Let me reiterate we will not rest until this well is shut, the environment is repaired and the cleanup is complete,” Obama said.

Through the early-morning hours Wednesday, BP put equipment into place. A team of experts examined conditions inside the five-story blowout preventer to determine how much pressure the injected mud would have to overcome.

A blowout preventer is a critical piece of equipment designed to shut down the well in the event of an emergency, but it failed to do so in the BP leak.

On Tuesday, congressional investigators reported that the London-based oil giant had three indications of trouble aboard the rig. The well unexpectedly spouted fluid three times in the 51 minutes before the explosion and pressure on the drill pipe “unexpectedly increased” before the blast.

A House Energy and Commerce Committee memo summarized preliminary findings of BP’s investigation into the disaster and said it “raised concerns about the maintenance history, modification, inspection, and testing” of the rig’s blowout preventer.

Hayward said Wednesday that the industry was dealing with an “unprecedented accident.”

“Well, as in all major accidents of this sort, what we’re seeing here is a whole series of failures,” he said. “We’ve identified in our initial assessment, at least seven. That investigation is far from complete.”

Hayward called the massive oil leak a “transforming event in the history of deep water exploration.”

It has been transforming as well in Plaquemines Parish, Louisiana, where frustration boiled over Tuesday night as residents hurting financially from the spill confronted officials from BP and the U.S. Coast Guard at a tense town-hall meeting.

“Everything is dying,” one woman said. “How can you honestly tell us that our Gulf is resilient and will bounce back? Because not one of you up here has a hint as to what is going to happen to our Gulf. You sit up here with a straight face and act like you know when you don’t know.

Fishermen and tour boat captains sit idle in the parish as thick crude invades the state’s shoreline. Fishing is a $2.4 billion industry in Louisiana.

“There is absolutely nothing I can say from this podium that’s going to make you feel better tonight,” Larry Thomas, BP’s manager for government and public affairs, told the crowd at Boothville High School.

“Over the next few months, BP is going to be tested to make it right with you for what has happened,” Thomas said.

But that promise wasn’t enough for many in attendance, who said they want a contract of sorts that specifically lays out a plan for compensation.

“Is it three months? Is it six months? What are you going to do to compensate the people that have lost their livelihood, maybe for many years?” asked Plaquemines Parish President Billy Nungesser. “We want to know today.”
 

– CNN