"A recent marine casualty resulted in significant damage to tank structures, piping and components of
a combination chemical / oil product carrier. Vessel-to-vessel loading operations were taking place at
anchorage and one tank became over-pressurized. Subsequently, three cargo tanks and three
ballast tanks on the ship suffered catastrophic structural failures that allowed hazardous cargo to
migrate throughout those areas. This incident caused the vessel to list and created a very dangerous
explosion hazard requiring costly and time-consuming lightering and repair operations. Additionally, it
presented a hazard to the port and persons involved.
The investigation is nearly complete and investigators have identified several causal factors, one being the failure of the high velocity vent valve which did not open and prevent over pressurization of the tank while it was being filled".
Read the safety alert to understand why the high velocity vent valve failed to operate, in this link: