Video: Overheated cargo caused Stolt Groenland explosion

The UK’s MAIB has found that the explosion aboard the chemical tanker Stolt Groenland was caused by heated cargo tanks warming a nearby temperature-sensitive cargo. The Cayman Island-registered vessel was carrying styrene monomer when she exploded on September 28th, 2019 in the port of Ulsan, South Korea.

A spontaneous, runaway polymerisation of the monomer occurred, in effect turning the styrene in polystyrene, exponentially increasing the temperature of the cargo tank and rupturing it. When air entered the compromised tank, the monomer vapour exploded, blowing the ship’s deck apart. Miraculously no one was killed.

“That Stolt Groenland’s crew were unaware of the elevated temperatures and polymerization of the styrene monomer in 9S, until warned by the activation of the high-level alarm on the bridge front, indicates that the temperatures of the non-heated cargoes were not monitored at all, and that no temperature alarms were set,” concluded MAIB.

“Had the temperatures of the styrene monomer been closely monitored and the maximum temperature of [30 C] stated on the certificate of inhibitor been adhered to, this accident would have been avoided.”