where this attaches to the stack, we want to make sure no leaks there. the bigger question, though, and one of the reasons they are increasingly saying they may not use this as a permanent fix is they're worried about a leak down here along the sea bed floor where the well goes deep underground. nothing they can do at this point. they're worried as they stop the pressure up here it puts pressure back down and perhaps there was some damage in the explosion down along the sea floor. that's one thing they worry about there. let's just take a closer look at this capping stack, take these out of the way so we can see this more clearly. this is the structure we're talking about. they turned these valves earlier today and this is what they shut down to stop the flow of oil. we're watching this. they say later tonight they'll have their first set of readings and could go as long as two days to determine whether they trust this is the big question and then how much do they trust it? do they trust it to shut down the well permanently until they drill the relief wells underneath? or do they decide we don't want to have this as a permanent solution, reopen some of these valves, but use the lines to