(July 20, 2008)--Federal investigators are in Houston looking for the cause of the deadly collapse of one of the nation's largest mobile cranes at a Houston refinery.
Four workers died in the collapse and seven others were injured.
Refinery and crane company officials say investigators with the Occupational Safety and Health Administration were at the site.
Baton Rouge, La.-based Deep South Crane & Rigging owns the 300-foot-tall piece of equipment.
A company spokeswoman said Deep South plans to work with federal investigators.
The crane hit the ground Friday with enough force to lift a worker off the ground at a LyondellBasell refinery in southeast Houston.
The Houston Fire Department says three of the injured were treated at the scene.
Two severely injured workers were taken by helicopter to Memorial Hermann-Texas Medical Center hospital.
LyondellBasell says their injuries were not life threatening.
Two other injured workers who were taken to a hospital have since been released.
OSHA Web Site