"A high-tech effort by BP to slow the oil gushing from its ruptured well head led to a large accident yesterday that forced the company to remove a vital containment cap for 10 hours. Robots, known as remote operated vehicles, were performing multiple operations at the disaster site when one bumped into the 'top hat' cap and damaged one of the vents that removes excess fluid, according to the US Coast Guard. The robots weigh around four tons, and are controlled from vessels on the surface using advanced IT systems with both manual and automated functions. BP removed the cap for nearly 10 hours ... in order to assess it after a discharge of liquids was noted from a key valve. The cap's removal left the oil gushing out of the wellhead, largely uninterrupted. Admiral Thad Allen, US National Incident Commander for the response, told the media that part of the problem was the number of robots conducting simultaneous operations at an immense depth. A dozen robots are circulating the wellhead."
Another factor that may hinder containment even more is the increasing potential for tropical storms
in that area of the Gulf.