"When you have an area that's leaking a little more, you get up to a pound a day, maybe a pound a half or even two, then we hit a threshold where, okay, we've got to do something about this," he told BBC Newshour.
"When you have an area that's leaking a little more, you get up to a pound a day, maybe a pound a half or even two, then we hit a threshold where, okay, we've got to do something about this," he told BBC Newshour.