An accident that resulted in one fatality and an injury occurred on the Hercules Offshore Rig 120 (the rig) contracted by Chevron USA Inc. (Chevron) to conduct sidetracking operations from Lease OCS-G-4903, Main Pass (MP) Block 30, Well No. A-14 ST01 (the well), in the Gulf of Mexico (GOM) offshore Louisiana, on 7 March 2009 at approximately 2158 hours. Lifting operations from the rig floor were in progress utilizing the rig floor air tugger (air-operated hoist) to position a 2- inch rubber hose, with internal steel construction rated for high pressure, for testing the well's 13-3/8 inch x 9-7/8 inch casing annulus. The fifty (50) feet, approximately 400 pounds, of hose assembly was lowered from the rig floor to the wellhead deck where the lower end of the hose assembly would be connected into the well's 13-3/8 inch x 9-7/8 inch casing annulus valve and the upper end of the hose assembly connected to the rig floor manifold.