Last Updated May 5, 2010 10:07 AM EDT
That means the Gulf spill is becoming far larger then the Exxon Valdez spill, in which about 10 million gallons were poured into the ocean. Recovery workers have been hard-pressed to stem the flow, with the oil first reaching Louisiana last Friday.
Yet there are a handful of techniques for cleaning up the mess, both through working beneath the waves -- an immense challenge, at 5,000 feet -- and atop, once the oil has surfaced. Here are seven:
Blowout prevention -- Within the oil industry, it's an accepted fact that oil drilling rigs and platforms are unsafe. Despite all safety precautions, there's always the possibility of an accident that could potentially destroy the entire rig, just as happened with the Deepwater. But when that does happen, a separate device is supposed to prevent an oil leak at the bottom: the blowout preventer. BP's bad luck was doubled when the BOP failed to activate. Deep-sea submersibles are trying to fix the device or install a new one to stop the flow of oil at its lowest point, but have failed so far.
Containment domes -- These devices, also called coffer dams, are the second of the three major methods BP hopes will eventually stop the leak entirely. Starting with one this week, BP will lower three 40-foot tall containment "domes" over the leaking sections of pipe on the seabed. Some oil will still escape, but the plan is to suck most of it up through the dome (which is actually more of a rectangle). This idea also reveals the essential crudity of our deep-ocean technology: there's nothing subtle about dropping just under a hundred tons of concrete onto a leaking pipe.
Relief wells -- Even if the above two methods are successful, BP will still work on a relief well over the coming months that, when finally completed, will divert oil away from the spill site. Drilling the relief wells is a more involved process than the original well, because the drill bit must work at an angle once it penetrates the seabed. The company says its relief well will cost it $100 million.
Chemical dispersants -- Combating an oil spill by dumping thousands of gallons of chemicals into the ocean sounds like a bad idea, but the "dispersants" that BP is using on the oil, sprayed from planes and helicopters, actually aren't that far off from common detergent. The dispersant works by breaking up the heavy oils, just like you see in commercials for dishwasher fluid. At the source of the leak, submersibles are injecting more dispersants into the oil as it jets out, preventing some of it from ever reaching the surface.
Oil skimmers -- Since some oil sits on top of the water, a clever skimming system can separate the oil to be siphoned away (and potentially even sold on the market like normal oil). Skimming devices can range from small to massive, but despite advances in the technology, none are large enough to deal with a Gulf-sized spill, at least without months of work.
Fire -- One of the oldest technologies known to man, this sounds like a quick solution to the oil: we all know that gasoline, at least, will burn off quickly and even explode. But the "sweet crude" welling up is actually a thick, heavy substance that doesn't always burn easily or evenly. The Coast Guard attempted to burn enough oil to prevent it from reaching the Louisiana coastline, but failed.
Booms and barriers -- Although incapable of actually cleaning up the oil spill, "booms" are floating barriers intended to keep the oil from spreading too far. The Coast Guard brought plenty to the spill, but rough seas rendered them ineffective when waves began sweeping oil right over the booms. Other barriers, more akin to fences, are sometimes used close to shore.
Of course, even if all of these methods worked perfectly to clean the oil, simply tracking where it is at any given time is a challenge unto itself. My colleague Erik Sherman just wrote up a good overview of the remote monitoring tools that help workers figure out where all the oil is going.
But as Erik points out, the monitoring technology is far short of perfect. That's even more the case for the cleanup technologies I've listed above; in fact, little has changed since the Valdez spill, which rewrote US oil-industry policy but didn't produce much innovation. Given the public outcry so far about the Gulf spill, however, we're likely to see a wave of new spill mitigation technologies in the coming years.
[Some pictures courtesy of BP]
More of our oil spill coverage:
Oil Spill Technology Improves, But Too Little and Too Late
How BP's Oil Spill Will Create a Gusher of Money for P&G's Dishwashing Liquid BP's Reputation As Much at Risk as the Gulf Ecosystem
Who's to Blame for the Gulf Oil Spill? BP, Halliburton and the Feds Are All Implicated
Gulf Oil Spill Exclusive: The Last Four Minutes of the Deepwater Horizon in Images