help us understand, yes, we have been told, this thing is not going to be a threat to us anymore, and it s dead but they are still trying to kill it again? reporter: absolutely. this is basically going to seal it off for good. the measure they will undergo today will involve the final process of what we are referring to is the bottom kill. that will be the continuation of digging the relief well. the relief well itself is something that has been dug right along the broken well. it goes down 17,000 feet, and they are within 100 feet of where they want to inject the combination of cement and mud and that should kill it off altogether. and it started off with the containment cap. and then, of course, the status kill, and then the bottom kill. and then the final step for many people, that battle is over