Bow Mariner tragedy: 15 years on, USCG reflects on safety improvements

When 174-m Singapore-flagged chemical and oil tanker Bow Mariner caught fire, exploded and sank on 28 February 2004, some 72 km off the Virginia coast in the eastern US, 21 of the 27 crewmembers on board perished.

In the 15 years since it occured, the tragic accident has had a significant impact on safety in the industry, USCG Lieutenant Mike Lawrence wrote in a story published on the Coast Guard website, helping to "bring forward numerous marine safety improvement impacts and lessons learned".

The fire began when residual chemical fumes from a previous cargo escaped into the cargo holds when the crew were ordered to open the cargo accesses to clean the vessel’s tanks.

At the time, the vessel was transporting more than 11M litres of ethyl alcohol on a voyage from New York to Texas after discharging methyl tert-butyl ether (MTBE) from 22 of its cargo tanks while in New York.

The fumes that escaped while the crew cleaned residual MTBE out of the vessel’s empty tanks created a highly-flammable mix of gases that ultimately caused the conflagration on board.

While the Coast Guard did not determine an exact ignition source in its formal investigation report for the vessel’s flag state of Singapore, it did highlight several contributing factors.

The report said Bow Mariner failed to "properly fully implement the company and vessel safety, quality and environmental protection management system, (SQEMS)". Inert gas was not used during the discharge of MTBE, a precaution the vessel’s SQEMS required to prevent fires on board.

The International Safety Management (ISM) code requires that an SQEMS be implemented by the vessel and its managing company; however, because the vessel was built before 1986, US law did not require it to inert its tanks when discharging its MTBE cargo. The lack of inerting and opening of the empty MTBE cargo tanks for cleaning "significantly increased" the likelihood of fire on board, as Lt Lawrence explained.

Ultimately, the captain’s decision to open the cargo tanks was a major safety violation that defied any explanation, according to the USCG report.

"The loss of Bow Mariner is considered one of the worst chemical tanker disasters in history and is a tragic reminder of the consequences resulting from unsafe chemical cargo handling practices," Lt Lawrence wrote.

• Inspecting tanks after inert gas injection
• Industry supports calls for IGS on small tankers
• OCIMF wants inert gas for all volatile cargoes
• Options for inert gas remain under active consideration

In terms of safety measures for incident response, Bow Mariner was not required to carry immersion suits for its crew because the vessel’s lifeboats were fully enclosed.

"Regulations have since changed, and a comparable vessel today is now required to carry immersion suits. Immersion suits are designed to help increase survival chances in cold waters. Had Bow Mariner carried immersion suits and its crew had the opportunity to don these suits, the survival rate could have been much higher," Lt Lawrence wrote.

The US Coast Guard investigation also discovered evidence showing that regular, effective emergency crew drills were not conducted on board Bow Mariner. During the course of the fire, subsequent explosions and the ship foundering, "the general alarm was never sounded nor was an announcement made to alert or direct the crew," the report found.

The USCG report found that during the emergency on board Bow Mariner, the captain left the ship without sounding distress calls, without conducting a muster for injured crew and without attempting to launch lifeboats amidst an atmosphere of general panic and confusion on board.

Current safety regulations require ships to conduct a fire drill and abandon ship drill monthly, and the USCG report noted that the lack of emergency preparedness on board was the result of insufficient training.

Coast Guard regional commanding officer Capt Kevin Carroll said "Coast Guard marine inspectors are trained to identify flaws in safety management and evaluate emergency drill performance."