USCG SAFETY ALERT – EXPLOSION AND FIRE DUE TO FAILURE OF CARGO PUMP BEARINGS

Failure of the bearing in the cargo pump allowed the shaft and impeller to shift and spin against the casing. The resultant friction caused extreme heat and possible sparks, which ignited the atmosphere in the tank, which had become rich in oxygen when the hatch cover was opened during cleaning. Proper maintenance of cargo pumps is advised.

The US Coast Guard has issued a Safety Alert stating that a chemical tanker recently suffered a tank explosion and fire at an offshore anchorage in the Gulf of Mexico. The explosion occurred in an empty cargo tank that had previously contained benzene.

 

After stripping the tank, the tankerman opened the tank top cover and an explosion ensued. The centreline bulkhead between the ignition space and the adjacent cargo tank ruptured. A fire also developed and was extinguished in twenty minutes by the ship's crew using a water/foam mixture. The pumpman was severely burned and the cargo hold was severely damaged.

 

While the investigation is ongoing, the cause appears to be that the upper bearing in the cargo pump failed, allowing the shaft and impeller to shift axially and spin against the end plate of the casing. The resultant friction caused extreme heat and possible sparks, which ignited the atmosphere in the tank.

 

Owners and operators are advised to ensure proper maintenance of cargo pumps.