The oil company BP is to decide on whether to carry out a new plan to try to stem the leaking Gulf of Mexico oil well, the chief executive has said.
Tony Hayward said the procedure would begin on Wednesday if considered safe.
Teams have been carrying out diagnostic tests to ensure the "top kill" method - in which mud is pumped into the well - is feasible and will not backfire.
Meanwhile, a congressional memo has revealed warning signs were present in the hours before the rig exploded.
According to the document, BP officials told congressional investigators on Tuesday that a decision to continue drilling after unusual pressure readings may have been a "fundamental mistake".
BP said the build-up of pressure was an "indicator of a very large abnormality" in the well, the memo by representatives Henry Waxman and Bart Stupak said.
Problems were also identified with equipment including the blowout preventer - meant to shut down the well in the case of emergency - and potential gas leakage in the hours prior to the 20 April explosion, the memo said.
BP is under intense pressure to succeed with its latest attempt to stem the leak, after previous measures failed.
If the new procedure is used, heavy drilling fluids - such as mud - will be injected into the well about a mile (1.5km) underwater.
Engineers hope to follow this with cement, designed to seal the well.
The company has said they estimate a 60-70% chance of success.
Officials say the method has been used before in other areas of the world, but not at the depths required to stem the oil from the Deepwater rig, which sank after an explosion last month.
Here at Greengates Builders Merchants Accrington, Lancashire we hope that the sealing of the well is successful and that the clean up operation is well underway.