An investigation into the cause of a fire and multiple explosions onboard an articulated tug and barge (ATB) that claimed the lives of two crew members in 2017 has named a lack of effective maintenance and safety management as the cause of the incident.
The ATB vessel Buster Bouchard/B. No. 255, owned by Bouchard Transportation Company, was anchored in the western part of the Aransas Pass Fairway, Anchorage approximately 3.25 miles (5.23 km) offshore from the Port Aransas, Texas, at the time of the explosion.
On 20 October 2017, at 0430 local time, the crews of the Buster Bouchard/B. No. 255 were preparing to get under way from anchorage to proceed into the Port of Corpus Christi when three explosions and a subsequent fire occurred on the bow of the barge.
The fire was extinguished on the same day at around 1100 local time. However, the 468 ft-long, double-hulled barge sustained more than USD5 million in damage and during the incident approximately 2,000 barrels of crude oil were discharged from the barge into the water or were consumed in the fire.
The National Transportation Safety Board (NTSB), found in its investigation that the explosion was caused by the ignition of flammable vapour that formed in a void space. The vapour was from crude oil that leaked into the void space from the number one port cargo tank through a corroded bulkhead.
During the post-accident internal examination investigators discovered two horizontal through-cracks in the bulkhead separating the forepeak and the number one port cargo tank. These cracks were found to be approximately 15 ft from the bottom of the tank and about 2 inches (5 cm) above transverse framing welded to the forepeak side of the bulkhead. The horizontal length of the higher crack was 13.8 inches and the horizontal length of the lower crack was 13.5 inches. The report states that the documented cracks in the area of the original bulkhead compromised the integrity of the cargo containment of the number one port tank.
The NTSB’s report noted US Coast Guard inspectors who examined the barge prior to the accident failed to identify unsafe conditions, which allowed the vessel to continue to operate at an increased risk to the crews, the environment and port facilities. Further, the investigation found that classification society American Bureau of Shipping (ABS) failed to act on its surveys that also highlighted discrepancies regarding the substandard maintenance and hazardous conditions of Buster Bouchard/B. No. 255.
For this reason, the NTSB concluded that the lack of communication between ABS and the Coast Guard prevented a co-ordinated effort to evaluate the structural condition of the tank barge and that the ineffective inspections and surveys by both these two parties and the failure to correct unsafe conditions contributed to the accident.
Following the investigation, the NTSB issued one safety recommendation to Bouchard Transportation to evaluate their safety management system with a third party to identify deficiencies.
The NTSB also issued safety recommendations to ABS and the US Coast Guard seeking the establishment of joint policy and procedures to share information including results and findings from audits, surveys, examinations, inspections, and all other applicable activities related to vessel safety.