For the first time in more than two months, the Macondo well is not leaking oil and gas into the Gulf.

The well has been shut in temporarily as part of the well integrity test. According to reports, engineers will huddle around 8:00 p.m. this evening to discuss whether the new cap, which was lowered on to the blowout preventer earlier this week, will effectively stop the flow over a period of time.

Kent Wells of BP is sending out updates on the well testing via Twitter. You can follow his announcements here.

Under the testing process, engineers planned to slowly close the cap, called a three ram capping stack, and to monitor the pressure in the well. A pressure of 6,000 pounds-per-square-inch (psi) or higher would signal that the well below the seabed had not been damaged. A lower pressure could indicate damage, raising the possibility that oil and gas was moving into underground pockets and possibly creating further problems.

CNN reports that the president will address the nation shortly.

BP cautions that the deployment of this cap system has never been attempted at this depth or under these conditions, and "its efficiency and ability to contain the oil and gas cannot be assured." Furthermore, BP says the relief wells remain the only sure way of permanently sealing the well.