BP yesterday lowered a new cap onto the ruptured Gulf of Mexico oil pipe, hoping to close its valves and cut off the flow of toxic crude once and for all.
Almost 13 weeks after the disaster began with a deadly explosion on the Deepwater Horizon rig, the end is finally in sight as engineers place the "Top Hat 10" device over the giant gusher a mile down on the sea floor.
BP chief operating officer said once the cap was connected and its valves closed to shut off the flow, critical pressure tests would be carried out to study the well's integrity.
"The best-case scenario: the pressures rise to the point we anticipate they would," Suttles told journalists. "We'd likely be able to keep the well shut in."
If the tests reveal the pressure is too low, the valves will have to be reopened but officials believe they would be able to ramp up the capacity of the containment system within days to capture all the leaking crude.
"This containment cap will have the ability to actually close down valves and slowly contain all the oil. Once we do that, we'll know how much pressure is in the well," the former Coast Guard chief Thad Allen heading the US response effort said.
"It could tell us that the well is withholding the pressure and we can shut the well in or just cap it, if you will. Either way, those are two pretty good outcomes," Admiral Allen said.
The feverish work in the murky depths of the Gulf come as officials race to take advantage of a stretch of fine weather in the midst of the Atlantic hurricane season.
The new containment system is also designed so that it can be disconnected and reconnected more easily in the case of a hurricane and has a built-in device that should give the first precise estimate of the overall flow.
Oil has washed up on beaches in all five Gulf states - Texas, Louisiana, Mississippi, Alabama and Florida - forcing fishing grounds to be closed and threatening scores of coastal communities with financial ruin.
And as robotic submarines attended the vital operations at the well site, the pain for Gulf residents was being laid bare in front of a presidential commission investigating the cause of the tragedy.
"I wish that we had the power to bring immediate solutions to stop the oil," said Senator Bob Graham, who co-chairs the seven-member commission, sitting in New Orleans.
"We do promise to give our very best efforts to find out what is happening and the enormous consequences of this spill on the lives and the livelihood and the culture of the Gulf region."
The independent commission is tasked with investigating the causes of the spill and the effectiveness of the response and making recommendations on ways to prevent future spills.
An estimated 35,000 to 60,000 barrels of oil has been gushing out of the ruptured wellhead since the BP-leased Deepwater Horizon sank spectacularly on April 22 after a deadly explosion. There was little optimism in the room as the hearing got under way, after a string of earlier failures from BP to cap the well.
"Even if BP caps this well tomorrow they've done so much damage to the Gulf it's a strange consolation plan," said Darwin Bond Graham, a sociologist studying how New Orleans has recovered from Hurricane Katrina.
BP said Monday the disastrous oil leak in the Gulf of Mexico has cost $3.5 billion (€2.78 billion), although the petroleum giant's shares rose sharply on reports it was poised to sell some of its assets.
If something goes wrong with the cap containment operations, BP is still drilling two relief wells, one of which could intercept and plug the gusher by mid-August.