Smith International has confirmed that two employees of its M-I Swaco venture are among the 11 missing crew members after the explosion and sinking of the Transocean semi-submersible rig Deepwater Horizon.  Transocean has said the other nine missing crew from the Transocean explosion are members of its staff.

Smith said there were five M-I Swaco employees on board the rig at the time of the Gulf of Mexico oil rig explosion and three returned safely.  Houston-based M-I Swaco is jointly owned Smith International (60%) and French services giant Schlumberger (40%).

“We are deeply saddened by this tragic event. Our thoughts and prayers are with our colleagues and the loved ones of those affected,” Smith boss John Yearwood said in a release.

Both the Coast Guard and Transocean have said that the hopes of finding the remaining missing crew alive are slim.

Although the cause of the Transocean explosion is unknown at this time, Transocean officials have confirmed that the semi-submersible explosion did involve a blowout on the MODU.  They have said that abnormal pressure must have accumulated inside the marine riser, and as it came up it expanded rapidly and ignited.

A federal oil rig explosion lawsuit was filed by the family of Shane Roshto Wednesday in Louisiana.  Roshto is one of the 11 missing seamen and his Deepwater Horizon lawsuit claims negligence by both BP and Transocean.

The Deepwater Horizon offshore drilling vessel was built in 2001 by Hyundai Heavy Industries in Ulsan, South Korea.  It is a Reading & Bates Falcon RBS-8D design rig with accommodations for up to 130 people.  The dynamically-positioned Deepwater Horizon can operate in waters up to 10,000 feet and can drill to 30,000 feet.