Throughout the night of May 25 to May 26, 2010, BP engineers gathered pressure testing information before giving final approval to a method known as top kill that engineers hope will halt the flow of crude oil and natural gas into the Gulf of Mexico waters. They plan to gather this morning to have the team re-examine the data and determine if they think it will work. Engineers also worked remotely overnight to rebuild a special valve system as well.

Top kill has been successfully used on wells that have blown out on land but never in waters this deep. Pressures at these depths can change the way things work. The company has pledged to keep the live video feed running during the procedure. Officials also warn that if the top kill goes forward that just watching the video will not give an indication as to the success or failure of the method. It will take at least two days to complete the process and determine if it looks to be working. Click here for the live video feed.

The top kill method includes pumping heavy mud into the 6-inch pipe to stem the flow. A special cement mixture will also be added toward the end of the process. Officials said that the next try, should this fail, would be ready to deploy in three or four days.

In the meantime, investigators have found a number of signs that problems were developing in the last few hours that engineers should have picked up on to prevent the April 20 explosion that led to the death of 11 people.