The United States Coast Guard (USCG) has issued a marine safety alert to remind vessel operators of the hazards of confined space entry.
The release comes after a recent casualty, which saw three people asphyxiate while working onboard a laid-up mobile offshore drilling unit (MODU). There were 10 crewmembers on the MODU preparing it for transport to a shipbreaking facility when the incident occurred.
According to the USCG alert, the crew were successful in dewatering three of the unit’s four legs. However, the de-ballasting system was inoperable in the fourth leg because piping and valves had been previously removed.
To continue the dewatering operation, the crew rigged a portable diesel engine driven pump to discharge the tanks. Each of the MODU’s legs had six decks. The first two uppermost decks had access hatches that allowed transfer of crew and equipment.
The remaining decks were accessed via manhole hatches that were too small to allow passage of the portable pump and had to be enlarged. As each ballast tank was fully discharged, the manhole cover at the bottom of the tank was enlarged and the pump was lowered.
Seven of the crew onboard were involved in the dewatering efforts: The superintendent, captain, rigging master, fitter, and an AB (AB2) were on a dinner break, while another AB (AB1) and the electrician were assigned to oversee the operation.
Without notifying anyone, AB1 descended into the leg to check the pump. The electrician became concerned when he failed to see AB1 on deck and descended into the leg himself, only to find AB1 collapsed and unconscious near the pump.
Once on deck, the electrician notified AB2 and the fitter about AB1’s collapse. AB2 then descended to assist AB1 while the fitter went to inform the captain. The captain, ship superintendent and fitter then notably – and without necessary safety equipment – descended into the leg to assist AB1.
Upon entering the upper part of the MODU’s leg, they noticed AB2 had collapsed and was now unconscious one level above AB1. At that time, the fitter was overcome by the vapours and collapsed next to AB2. Ultimately, AB1, AB2 and the Fitter died.
Following the tragedy, USCG urged all vessel owners, operators and crew members to:
● Obtain the requisite level of knowledge and training of confined space entry procedures including emergency and rescue procedures;
● Ensure crews undergo periodic confined space training and participate in routine and practical onboard emergency drills;
● Verify all required confined space entry and rescue safety equipment is onboard, maintained, tested and fully functional;
● Continually appreciate the dangers involved in confined space entry and educate themselves by further study.