BP's latest effort to stanch the gush of oil into the Gulf of Mexico failed, when a 98-ton containment dome immediately became ice-clogged and useless. BP CEO Tony Hayward said that although the oil flow continues unchecked, his company's overall response has been "far more effective than any spill response heretofore in terms of containment offshore and preventing oil from getting on the shore, and that is a fact." But with the oil slick still growing, what does BP have left in its bag of tricks? (Watch Rachel Maddow outline BP's next options.)

What went wrong with the 98-ton dome?
BP successfully maneuvered the four-story concrete-and-steel dome on top of a major leak, hoping to send 85 percent of the gushing oil to a ship on the surface, but a frozen slush of gas hydrates — an icy mix of methane and water — clogged the container's exit hole. The dome now sits on the ocean floor, 200 meters from the leak.

What's BP's Plan B?
Deep-sea robot submarines are already shooting chemical dispersants directly at the source of the leaks. The EPA approved the plan Monday, and BP says test projects show the chemicals reduce the amount of oil that reaches the surface.

Is there a Plan C?
Yes — BP seems willing to try "anything people can think of," says LSU environmental studies professor Ed Overton. In the next few days, BP will try capping the leak with a smaller, 2-ton containment dome, or "top hat." Engineers say the 5-foot-tall, 4-foot-wide top hat should fare better with the gas hydrates because it holds less freezing water. Of course, that also means "it's unlikely to be as effective in capturing all the oil," says Hayward.

Plan D?
As early as next week, BP will try a "junk shot," in which it shoots golf balls, bits of tire and rope, and other refuse down through the failed shutoff valves in an effort to clog and block off the pipe. This technique was successful with Kuwaiti oil wells during the Persian Gulf War, but has never been tried in water this deep.

Plan E?
BP is considering severing the pipe that leads up from the leaking well and fitting on a larger pipe that would direct the oil into surface tanker ships. This is risky, though, because if it fails, the flow of oil will increase considerably.

Dare we ask... a Plan F?
All the other interventions are designed to slow the leak while BP drills two more wells to relieve the pressure on the gusher so it can be permanently plugged. These new wells are "virtually guaranteed to work," according to the Houston Chronicle, but will take up to three months to complete.

How much is all this costing BP?
The company says it has spent $350 million on the spill, including $25 million grants to Florida, Alabama, Mississippi, and Louisiana, and $3.5 million in economic-damage claims (the average payout: $5,000).

Sources: New York Times, Politico, AP, Houston Chronicle, Washington Post, Bloomberg