Two offshore workers injured in ‘black plume of smoke’ during work at U.S. platform

After looking into circumstances surrounding injuries two workers suffered during a skillet installation at an offshore platform on the Outer Continental Shelf (OCS), which resulted in a medical evacuation, the U.S. Bureau of Safety and Environmental Enforcement (BSEE) has come up with recommendations for oil and gas operators and contractors to assist in preventing such incidents in the future.

In a safety alert, BSEE explained that two workers were injured on an offshore platform while installing a skillet, which is the steel circular joining plate inside a section of piping. At the time of the incident, the workers were on scaffolding and unbolting a 10-inch flange. Upon determining the skillet was the wrong size, the supervisor instructed a third worker to join the initial two workers on the scaffolding to take measurements of the skillet to verify the pipe size.

After the third worker saw that the other two had already unbolted the flange to install the skillet, he instructed them to pass down the gasket, so that, he could verify the pipe size, then exited the scaffolding and relocated to the tool shed to retrieve a fall protection harness. The two workers, who were left on the scaffolding, became alarmed when a handheld gas detector signalled the presence of gas.

At the same time, they heard pressure escaping between the pipe flange opening while the third worker, who was still in the tool shed, heard "a rumbling sound and loud noise," and looked in the direction of the noise to see "a black plume of smoke." In addition, he noticed the other two workers were being exposed to the material being emitted from the gap in the parted flange.

Furthermore, the two workers on the scaffolding, which experienced smoke inhalation and described feeling "a burning sensation," were quickly transported to the nearest hospital by air transport for further evaluation. Bearing this in mind, the BSEE personnel conducted an on-site investigation on 16 September 2022 and searched for any isolation sources near the verified isolation points.

The U.S. regulator found no isolated sources or ignition sources in the incident area and it also determined that all equipment was properly installed per the hazardous area classification drawings. The BSEE inspected the tools and equipment, which personnel on board reported using, and determined these were correctly rated for the area.

Moreover, the regulator's investigation of the incident revealed that workers were not aware of the possible hazards within the piping, and no purging or flushing of the piping was carried out before the work was done. Therefore, the U.S. regulator came to the conclusion that the personnel failed to identify the possibility of pyrophoric materials within the piping.

With this at the forefront, the BSEE recommends that operators and contractors implement and follow a fire and explosion management plan and safe work procedures when working with tanks and vessels where pyrophoric iron may be present. The regulator outlines that the plan and procedures should address ignition sources, oxygen, and fuel sources.

The U.S. regulator also advises operators and contractors to identify possible ignition sources, including pyrophoric materials that can form in both sour and sweet sites, automatic flare stack igniters, electrical discharge from improper bonding/grounding, and lightning.

Additionally, the BSEE underscores that operators and contractors should determine how oxygen could enter the tank through possible entry points like the thief hatch, extinguished flare stack, open valves, pipes, and hatches.

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