Looking at that track record, many engineers are scratching their heads. Engineers are trained to evaluate and mitigate risk. Every day, they build cars, trucks, airplanes, elevators, rockets, medical devices, and other products that have to control a package of energy. Sometimes that package is powerful, but engineers generally find a way to regulate it. In almost every case, they are successful in handling gasoline, rocket fuel, electricity, and, yes, lithium-ion batteries.
But in almost no case do they smack their hands together and say, "The risk is zero."
It's hard for most of us to imagine the external pressures that must have been brought to bear on Boeing staffers. For the past two-and-a-half months, Boeing has been deluged with press inquiries. Its story has been told in virtually every newspaper and radio broadcast. Its engineers and executives have lived on precious little sleep. And its stockholders have undoubtedly been breathing down the necks of management. So a public discussion of engineering risk probably hasn't come up high on the company's priority list.
For those reasons, it's much easier to say the risk is zero. That's what consumers want to believe about every product they touch, anyway. And it's what they usually believe when something goes wrong and they start phoning lawyers.
So the easy solution is for the company to say "zero." No risk. It's impossible. Fire can't begin, develop, or be sustained.
Just don't tell that to engineers.