Reply #5: So they've created a huge environmental disaster

[high density]

and lost a $560 million rig, all because they couldn't put in a $500k safety valve? That's like buying a car and then worrying about the cost of the gas cap.

The efficacy of the devices is unclear. Major offshore oil-well blowouts are rare, and it remained unclear Wednesday evening whether acoustic switches have ever been put to the test in a real-world accident. When wells do surge out of control, the primary shut-off systems almost always work. Remote control systems such as the acoustic switch, which have been tested in simulations, are intended as a last resort.