http://news.yahoo.com/s/ap/20100529/ap_on_bi_ge/us_gulf_oil_spill BP says so far, Gulf well plug isn't working By BEN NUCKOLS, Associated Press Writer Ben Nuckols, Associated Press Writer 12 mins ago .COVINGTON, La. â A risky procedure is failing to stop the oil spewing into the Gulf of Mexico, and BP said Saturday it is considering scrapping it in favor of yet another method to contain the worst oil spill in U.S. history. The comments from BP PLC chief operating officer Doug Suttles came amid increasing skepticism that the "top kill" operation â which involves pumping heavy drilling mud into a crippled well 5,000 feet underwater â would halt the leak. It's the latest in a series of proposed solutions BP has tried â including a gigantic box placed over the leak and a tube inserted to siphon the oil away. The box failed after ice-like crystals clogged it, while the tube was removed to make way for the top kill after it sucked up more than 900,000 gallons of oil. The top kill began Wednesday, and "to date it hasn't yet stopped the flow," Suttles told reporters at Port Fourchon. "What I don't know is whether it ultimately will or not." If the top kill fails, BP would cut off the damaged riser from which the oil is leaking and cap it with a containment valve that's already resting on the seafloor. BP is already preparing for that operation, Suttles said. Since the top kill began Wednesday, BP has pumped huge amounts mud into the well at a rate of up to 2,700 gallons per minute, but it's unclear how much is staying there. A robotic camera on the seafloor appeared to show mud escaping at various times during the operation. On Saturday, the substance spewing from the well appeared to be oil, experts said. BP has also tried several times to shoot assorted junk into the well's crippled blowout preventer to clog it up and force the mud down the well bore. That, too, has met with limited success. Interior Secretary Ken Salazar, addressing reporters after he spoke at a high school graduation ceremony in Denver, echoed what Suttles said and said officials were evaluating the next step. He said the relief well was the ultimate solution, but said something was needed to stop the spill until then. "We're doing everything with the best minds in the world to make sure that happens," he said. The oil spill began after the Deepwater Horizon drilling rig exploded in April, killing 11 people. It's the worst spill in U.S. history â exceeding even the Exxon Valdez disaster in 1989 off the Alaska coast â dumping between 18 million and 40 million gallons into the Gulf, according to government estimates. Experts and other observers were growing increasingly skeptical that BP would be able to plug the well. Eric Smith, associate director of the Tulane Energy Institute, said Saturday that the top kill appeared headed for failure. "They warned us not to draw too many conclusions from the effluent, but ... it doesn't look like it's working," he said. BP had pegged the top kill's chances of success at 60 to 70 percent. The company says the best way to stop the flow of oil is by drilling relief wells, but those won't be completed until August. Chris Roberts, a councilman in Louisiana's Jefferson Parish, said he was frustrated by BP's failures and perceived lack of transparency. "We're wondering whether or not they're attempting to give everybody false hope in order to drag out the time until the ultimate resolution to it" â the completion of the relief wells, Roberts said. Meanwhile, Coast Guard and Minerals Management Service officials heard a sixth day of testimony during hearings into the disaster in Kenner. David Sims, BP's drilling operations manager for exploration and appraisal in the Gulf of Mexico, testified he was aware of well problems experienced by the Deepwater Horizon's drilling crew in the weeks and months leading up to the explosion. He said there were no serious problems the day the rig exploded.