"Joe the Plumber" became a household name in 2008, but will anyone ever know the identity of the plumber who may have brought BP to the brink of stopping the oil gushing into the Gulf of Mexico.

Six weeks ago, Robert Bea, an engineering professor at the University of California, Berkeley, received a late-night call from an apologetic "mystery plumber." The caller said he had a sketch for how to solve the problem at the bottom of the Gulf. It was a design for a containment cap that would fit snugly over the top of the failed blowout preventer at the heart of the Gulf oil spill.

Professor Bea, a former Shell executive and well-regarded researcher, thought the idea looked good and sent the sketches directly to the US Coast Guard and to a clearinghouse set up to glean ideas from outside sources for how to cap the stubborn Macondo well.

When Bea saw the design of the containment cap lowered onto the well last week, he marveled at its similarity to the sketches from the late-night caller, whose humble refusal to give his name at the time nearly brought Bea to tears.

"The idea was using the top flange on the blowout preventer as an attachment point and then employing an internal seal against that flange surface," says Bea. "You can kind of see how a plumber thinks this way. That's how they have to plumb homes for sewage."

BP has received 300,000 ideas from around the world for how to cap the well after decades-old methods failed. Everyone from amateur inventors to engineers, Hollywood stars to hucksters, have swamped the unified command with ideas.

BP executive Doug Suttles says the new containment cap design came from weeks of trial and error. "We've been adding and trying new things constantly," Mr. Suttles said last week.

The design was originally intended to increase BP's ability to siphon oil from the well to containment ships on the surface. But in the past two weeks, it became clear to the company that the design, if it passed certain well integrity tests, could also be used to stop the flow altogether. If successful, the containment structure will be a turning point in the Gulf oil spill drama.

BP spokesman Mark Salt says, "There's no way of finding out at the moment" whether Bea's forwarded suggestion from the self-described "lowly plumber" made it into the design. "There's also a good chance that this was already being designed by the time this [tip] came in."

On the other hand, Mr. Salt adds, "I'm sure we've used bits and pieces of suggestions [from the outside] and have picked things out that could be used going forward."

As part of the response, the BP oil spill unified command has set up a triage of more than 30 technical personnel who put suggestions into three buckets: not possible; already considered; or feasible. According to the website, there are about 100 ideas from the outside being considered as ways to help stem the wellhead flow.

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