Crews are fine tuning the containment cap over the fractured Deepwater Horizon riser after it was moved back over the leak late Wednesday.
Earlier on Wednesday one of the robotic submersibles apparently collided with the structure and closed a vent.
Concern over the possibility of hydrates, ice-like crystals creating pressure inside, forced BP to remove the cap for several hours.
Meanwhile on the surface, work that began earlier in the day both off shore and along Pensacola Beach continued overnight.
Teams moved in to clean-up the latest wave of oil to wash-in, dotting the pristine white sand and smothering marine life.
"To actually see a live crab that's kinda half in and half out of the oil, it just really makes you sick to your stomach," said Pensacola resident Patricia Holt.
Federal research teams have confirmed what independent scientists have been saying for weeks.
They've identified massive clouds of oil more than 3,000 feet underwater
That stretch for miles from the spill site.