"The sad part is it could have been prevented with an emergency shut off valve. Some countries REQUIRE the valves to be put in place".
Oh God - you simpletons. You have no idea what you are talking about. Try asking questions and not pretending like you know anything about this. It's like saying they weren't wearing a seat belt. They didn't have a drain in place for the toilets! They put the wrong batteries in the smoke alarm! Wrong remote control code!
There are multiple protections supposed to be in place and the Blow Out Preventer was definitely in place. But it didn't work. They don't know why yet.
You probably didn't learn anything about this in high school or during your liberal arts degree.