Published: Sep 18, 2010 8:44 PM EDT
Updated: Sep 18, 2010 5:44 PM EDT

ON THE GULF OF MEXICO (AP) - Engineers say they have to finish one more pressure test to ensure the cement seal on BP's blown-out well will hold.       

Once the pressure test is finished and officials are confident the seal will hold permanently, the well will be declared dead. Rich Robson, the offshore installation manager on the Development Driller III vessel, says the 74 barrels of cement pumped in Friday has dried.
      
Robson says the pressure test will happen around 11 p.m. CDT and will take about half an hour. The test is the only way to ensure the well is dead.
      
Engineers will exert 15,000 pounds of pressure against the cement plug to make sure it won't budge. They should know by midnight CDT if the seal will hold.