The National Transportation Safety Board has released its marine investigation report into the May 15, 2024 collision of a towing vessel and its two loaded tank barges with terminal infrastructure in the Galveston Channel.
The accident resulted in one barge striking the Pelican Island Bridge and spilling about 20,000 gallons (75,708 litres) of vacuum gas oil, causing an estimated $8.4 million in total damages and cleanup costs.
The steel-hulled towing vessel LCPL Phillip C George, operated by Martin Operating Partnership, was departing the Texas International Terminal at 09:41 when strong flood currents pushed its port quarter into a terminal dolphin.
The force of the impact broke the port coupling and centre line between the barges, leaving the lead barge, MMLP 321, held by only one starboard wire.
As the MMLP 321 drifted perpendicular to the bridge, its aft port corner struck a power transmission pole at 09:46, causing sparking electrical cables to fall onto the deck and into the water.
The final starboard coupling wire parted immediately after this contact, leaving the barge to drift completely free before it struck a pier supporting both the abandoned railroad bridge and the Pelican Island Bridge.
Falling concrete debris from the railway bridge punctured the cargo tank of the barge, releasing the heavy petroleum byproduct which then drifted westward past the bridge.
A rescue boat from Texas A&M University at Galveston retrieved the uninjured deckhand from the grounded barge at 09:51 while the captain notified emergency services.
The safety agency determined that the actual tidal current speed during the incident reached up to 1.8 miles per hour (2.9 kilometres per hour), which was nearly double the peak predicted speed.
Investigators concluded that the probable cause of the contact was the inability of the captain to overcome the stronger-than-predicted tidal current as the strung-out tow exited the protection of the terminal breakwater.
Following this accident and two similar flood-tide collisions within an 18-month period, the US Coast Guard implemented strict departure rules at the Texas International Terminal.
Under the new policy, movements are banned when flood currents exceed 0.6 miles per hour (0.97 kilometres per hour), an assist boat is mandatory, and tows can no longer be strung out.