In the weeks before the Deepwater Horizon spill, an accident on the rig damaged a crucial piece of safety equipment, according to last night's "60 Minutes" on CBS.

According to a Transocean worker who survived and was interviewed by "60 Minutes," part of the blowout preventer's seal broke, and when this was brought to the attention of a supervisor, the response was that it was "no big deal." Another part of the blowout preventer--the control pod that connects the device to the surface -- also had problems weeks prior to the accident, according to the worker, Mike Williams.

Despite these troubling signs, operations continued. Williams said that in safety meetings, BP and Transocean managers feuded over how to proceed, with BP pushing to move quicker. BP ultimately won.

"[T]here was sort of a chest-bumping kind of deal. The communication seemed to break down as to who was ultimately in charge," Williams told "60 Minutes."

Flash forward to after the accident, with BP's CEO saying Transocean was responsible for the rig's operations. "It was their rig and their equipment that failed, run by their people, their processes," Tony Hayward told the "Today" show.

Dr. Bob Bea, a UC Berkeley engineering professor interviewed by "60 Minutes," said the pre-accident problems with the blowout preventer should have been fixed immediately. Bea added that when BP won the argument about how to seal the well, its methods--while faster--were more dangerous than Transocean's, and may have caused the blowout.

Last week, BP told members of Congress that the well had failed a key pressure test hours before the explosion. According to Bea, not even that test could be relied upon, given the damage to the part of the blowout preventer that sealed the well.