Despite the furious efforts of some cleanup crews wielding sophisticated equipment, experts believe most of the oil that is leaking into the Gulf of Mexico will likely make it to shore.
How much oil can be scoured from the waves will depend in part on weather and tides - and on the technology that the oil and gas industry can bring to bear on not only cleaning up the spill but stopping the underwater leak.
But those who work in oil-catastrophe response are not optimistic.
Mike Miller, chief executive officer of SafetyBOSS Inc., a Calgary-based company that gained renown for its response to burning oil wells in Kuwait, thinks it's unlikely even 10 per cent will be picked up before it hits shore. Joel Hogue, the president of Ohio-based oil spill training firm Elemental Services & Consulting, Inc., says 25 per cent is about what people should hope for.
That still leaves a vast quantity of oil that crews may be unable to prevent from washing onto the marshes, beaches and harbours that line the Gulf of Mexico.
Cleaning up a spill is "like trying to capture a greased watermelon," Mr. Hogue explained. "You do the best you can."
The problem stems from a well 1,500 metres below surface that continues to pour oil into the water. Officials have said 5,000 barrels a day are escaping, although The Wall Street Journal reported it could be as high as 25,000. At that rate, the current disaster has nearly equalled the amount of oil leaked by the 1989 crash of the oil tanker Exxon Valdez into an Alaskan reef.
Mr. Miller, whose firm has helped stop out-of-control wells across the world, faulted first-response crews for making a bad situation much worse.
When an explosion on the Deepwater Horizon drilling rig ignited a massive fire on April 20, fire boats raced to put it out. Pictures show at least four vessels pumping massive streams of water onto the rig.
That was a mistake, Mr. Miller said.
"Why they put the fire out is beyond me," he said. "Basically once it was burning it's not going to get any worse. But when they pulled all those fire boats out there, the result was they sunk the rig by filling it full of water."
He blames the oil leak on that act, since the sinking oil rig took with it the main connection to the well, which is located 1,500 metres below water. That allowed oil to leak out. Had the fire been left alone, the oil would have burned instead - a more palatable choice, he said.
A major part of the emergency response now lies in stanching the flow of oil, which has continued in part because a key safety device - known as a blowout preventer - failed to function. The size of a boxcar, a blowout preventer sits on the seabed floor at the top of the well, and is capable of shutting down the oil flow using several different methods. Blowout preventers are typically designed to work even if they lose a hardwire connection to the rig above.
For a reason BP officials have yet to explain, that device malfunctioned, leaving operators with few other options. Divers have been sent down to fix equipment in water up to 100 metres deep. But this well is far deeper. One option may be to trap the oil underwater and funnel it to the surface, although that has never been tried at this depth - and will likely take weeks to attempt.
"These people are dealing with uncharted territory. They've never dealt with this," said Denis Chenard, an Ottawa-based marine specialist.
The most permanent solution involves drilling a second "relief well" into the first, then injecting cement or heavy mud to stop the flow - a process that BP has warned will take two to three months.
That puts tremendous pressure on the cleanup crews who, along with an ever-increasing volume of oil, also have to deal with the fact that unlike the Exxon Valdez, the oil is not coming from a specific point. As it rises to the surface, it is dispersed by currents, making it difficult to corral.
Many of the cleanup methods, however, remain similar to those employed in Alaska two decades ago. Chemicals are used to disperse the oil. Booms are used to collect it. A bevy of different kinds of skimmers are used to clean it off the water.
By the time it hits shore, experts said, crews will have to sort between some 30 different techniques depending on the type of terrain that is contaminated.
It won't be easy. When Mr. Hogue trains people, the first thing he tells them is they must contain, control and stabilize a spill.
And in the Gulf, he said, "right now they do not have containment. They do not have control. And it is not stabilized."