Or take the Deepwater Horizon disaster itself, which was preceded by so many instances of corner-cutting and poor decision-making that an accident was practically preordained. Drilling one of the deepest wells in history, the project used only one strand of steel casing, when it should have used at least two. Halliburton recommended that BP use 21 “centralizers,” which help ensure that the well doesn’t veer off course as it goes deeper into the earth, but the company used just a half-dozen. BP failed to conduct a crucial test to make sure that the cement holding the well at the bottom of the sea was sturdy enough.

Image In March 2005, firefighters worked to put out a fire after an explosion at a BP refinery in Texas City, Tex. Credit... Brett Coomer/Houston Chronicle, via Associated Press

And the engineers for BP on board consistently ran roughshod over subcontractors like Halliburton, who openly worried that BP was making decisions that could have catastrophic consequences. “This is how it’s going to be,” one BP engineer reportedly said, overruling a contractor on the critical question of when to replace the drilling mud  which keeps explosive natural gas from flowing out of the well  with seawater.

What makes this all the more shocking is that BP was drilling what’s called a wildcat well, meaning it was drilling in an area that no other company had drilled before, so it had no knowledge of the conditions. For most oil companies, that would be all the more reason to take extra precautions. Yet BP did just the opposite.

Listening to Mr. Hayward’s responses on Thursday only reinforced the feeling that the company still didn’t understand what it took to instill a culture of safety. He kept saying that the blowout preventer was supposed to be a fail-safe mechanism that would keep the well from raging out of control. But other companies know that it is far too dangerous to depend on the blowout preventer alone and they build in additional safeguards, so that a problem can be dealt with long before the blowout preventer is needed. Asked about the lack of that important cement bonding test, Mr. Hayward blithely replied that he wasn’t a cement engineer so he couldn’t make a judgment about the decision.

Most telling of all, Mr. Hayward consistently denied knowing of any problems on the rig. As far as he knew everything was fine  until it wasn’t. But drilling a well offshore, miles into the earth, is one of the most dangerous activities in the world. Most companies will shut down a well at the first sign of serious trouble and kick the decision-making up to top management. The price of making a big mistake is simply too high. If Exxon Mobil had been running the Deepwater Horizon well, it is implausible that Mr. Tillerson would not have been informed of the problems. And he would also have had to approve any fix. That Mr. Hayward and his top deputies knew nothing about the problems on the Deepwater Horizon well is, by itself, a serious act of negligence.

Changing a company’s culture is always hard, no doubt about it. And it is especially hard for a company like BP, which has had such enormous success these last few years, reaping $14 billion in profits last year alone. For such companies, it often requires a crisis to change. Microsoft changed after its antitrust trial a decade ago. Tyco International changed after its chief executive, Dennis Kozlowski, went to jail. And chances are, BP is now going to change, too.