BSEE Report: Failure to recognize moisture barrier was not a walking surface leads to fatality

The incident

A three-member construction crew, employed by DCOR, was repairing a section of the galley floor in the main living quarters, on the first floor, that had sustained water damage.

The main living quarters building is located at the drill deck level. The flooring consisted of a layer of linoleum, a 4-by-8-feet sheet of 1-inch plywood, a 1.5-by-3-inch wooden floor joist, and a 5- millimeter composite flooring (moisture barrier) material set on top of a steel frame.

The crew removed the damaged material in a 7-by-7-feet area of the galley floor, leaving only the 5- millimeter moisture barrier.

At approximately noon, as the victim replaced the wood floor joists while standing on the 5- millimeter moisture barrier material, a welder, the injured person (IP), exited the kitchen area, walked around the outside of the living quarters, then into the galley.

The IP continued across the galley floor, then stepped into the unbarricaded work area and onto the 5-millimeter moisture barrier.

The weight of the IP stepping onto the moisture barrier caused it to collapse. Both the IP and victim fell through the floor and approximately 80 feet into the Pacific Ocean.

The IP swam back to the platform where he was helped out of the water by platform personnel. Realizing the victim could not swim, a few of the platform personnel jumped in the water, against the orders of the Person-in-Charge (PIC), in an attempt to rescue him.

The victim was manually lifted onto the plus 14-foot deck. Platform personnel initiated CPR, then transferred the victim to a motor vessel. CPR and medical care continued until the crew boat arrived at Ventura Harbor, at which time the victim was transported, by ambulance, to Ventura County Medical Center, where he was pronounced dead.

An autopsy report summarized the cause of the victim’s death as an accidental drowning.

Probable cause

Based on the investigation, BSEE concluded the cause of the fatality and serious injury was the failure of the construction crew and authorizing personnel to recognize that the 5- millimeter moisture barrier was not a walking/working surface and that it could not support their weight.

The victim and IP’s combined weight caused the barrier to break, which resulted in them falling approximately 80 feet into the Pacific Ocean.

Considering the totality of circumstances, BSEE concluded that the death of the victim was the result of:

• The work crews’ or appropriate personnel’s negligence to place a barrier around the area to prevent unsafe access into the work area by unauthorized/other workers;
• Failure of the construction crew, the supervisor and/or qualified designee to inspect the work area, or to review relevant engineering drawings to verify structural integrity of the flooring materials prior to starting the task;
• The crew’s lack of situational awareness that the 5-millimeter moisture barrier was not a walking surface. The IP stepped into the work area, causing it to collapse, resulting in the IP and victim falling approximately 80 feet into the Pacific Ocean.

Recommendations

Taking the above into consideration, BSEE recommended the following:

• Operators develop task-specific JSAs for every task and ensure they are implemented in each stage of the task.
• The Ultimate Work Authority, or qualified designee, review and approve the effectiveness of any barriers prior to the task(s) and communicate all associated hazards to all personnel.
• Operators evaluate the effectiveness of facilities permitting system including the human factors elements.
• Operators train employees on water emergency rescue and associated risk to avoid further injuries to personnel.
• Rescues should be strictly based on the operator’s emergency rescue policy and procedures including fall and water emergencies.
• Operators consult relevant drawings during the planning phase of any task to help understand any risk associated with the intended task or project.

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