The Story

A 160-foot supply boat was off-loading cargo to an offshore drilling rig in six to eight foot seas. The vessel pitched down as a tank of liquid nitrogen was being lifted from its cradle, displacing the tank and skid from the at rest alignment. When the vessel rose again on the next swell, the tank and deck collided with sufficient force to break the valve attached to the tank bottom. Liquid nitrogen began to pour from the tank to the deck of the vessel—then the main deck plate cracked, allowing the nitrogen to rush into the engine room. The tank was quickly swung out over the water and allowed to drain; damage to the engine room was minor. However, the damage to the main deck was severe and required extensive repair.

Lesson Learned

Unexpected hazards may exist when handling containers of cryogenic materials. These materials can be dangerous under working conditions that are normal for most products.