Shares of Halliburton (NYSE:HAL) tumbled 11% Thursday upon news that it knew its recommended cement used to seal BP Plc's (NYSE:BP) Macondo well was unstable in tests and may have contributed to the April 20th blowout, according to a report from a national commission investigation.
The National Commission said documents Halliburton provided suggested that as many as three tests of the mixture were carried out, in February and April, and found the mixture to be unstable.
The companies "both had results in March showing that a very similar foam slurry design to the one actually pumped at the Macondo well would be unstable, but neither acted upon that data,"
according to a letter. --Zacks.com