Federal investigators believe a “thermal runaway” in the lithium-ion battery of a handheld radio caused a fire on an oil tanker docked at a Baton Rouge, La., fuel terminal.
The captain of the 800-foot S-Trust discovered a fire in the bridge at about 3:30 pm on November 13, 2022. Crewmembers mustered in firefighting gear and extinguished the flames about 20 minutes later.
By then the damage had been done. The Liberia-flagged crude oil tanker required $3 million in repairs, a figure that includes replacement of the entire bridge navigation, communications, and electronics suite.
The National Transportation Safety Board concurred with the Bureau of Alcohol, Tobacco, Firearms & Explosives (ATF), which traced the fire to a runaway cell in a lithium-ion battery.
“The closed-circuit camera on the bridge captured an orange flash immediately followed by a puff of smoke in the area of the communications table where batteries and chargers for hand-held radios assigned to the bridge were located,” the NTSB report said.
“Following the flash, smoke and flames were seen growing and expanding as combustible material was consumed by the fire,” the NTSB continued. “The ATF concluded that the fire was caused by one of the lithium-ion battery cells on the communications table exploding.”
According to the report, a thermal runaway is the term for a battery cell that overheats and combusts. This type of reaction is not limited to lithium-ion batteries. The chemical reaction that causes it can happen with “damaged, shorted, overheated, defective, or overcharged” battery cells.
S-Trust arrived at the Genesis Port Allen Terminal on November 11, two days before the fire, to offload its cargo of high-sulfur fuel oil. Cargo discharge operations were underway when the fire started. The bridge was unoccupied at the time because the ship was docked.
The master noticed something amiss when the closed-circuit television (CCTV) feed for the bridge cut out abruptly, the NTSB report said. He went upstairs to the bridge to check the camera. Smoke escaped from the bridge as soon as he opened a door to the space, activating a hallway alarm.
The bridge itself was not outfitted with a smoke alarm, nor was it required to have one.
A flurry of activity followed. The master rushed to the cargo control room and ordered the chief mate to halt cargo operations. The chief mate then alerted terminal officials, who contacted the fire department.
The master rushed back upstairs to fight the fire. He opened a door from the starboard side bridge wing, which afforded a good view of the fire. He later told investigators the fire was coming from a communications table where handheld radios were charged.
“The master directed the crew to muster into two fire teams — one on the portside bridgewing and the other on the starboard-side bridgewing,” the report continued.
“Once the master received notification that all of the electrical power to the bridge was secured, the fire teams began fighting the fire through the port and starboard bridge doors using hoses.”
The fire was out by 3:50 pm. The local fire department responded about 10 minutes later and confirmed the flames were fully extinguished.
In addition to water, foam, CO2, dry chemical, and powered agents can work on lithium-ion battery fires.
“However,” the report said, “if the battery fire cannot be extinguished, personnel should attempt to allow the pack to burn in a controlled manner.
This, it added, “includes watching for nearby cells that may also experience thermal runaway and extinguishing other combustibles that may catch on fire.”
CCTV footage from the ship showed the fire’s origins. The video captured an orange flash near the communications table at about 3:27 pm followed by smoke. Roughly 90 seconds later, there was another flash as an object launched toward the starboard side of the bridge, landed on the floor, and continued to burn.
Smoke and flames continued to grow for the next six minutes, rendering the CCTV camera inoperable, the NTSB report said.
Investigators focused on the communications table on the bridge, which had charging stations for both Motorola and Entel handheld radios.
Two Motorola units were powered by lithium-ion batteries with a third powered by nickel metal hydride cells. The Entel radios featured metal hydride batteries, the report said.
Although uncertain, a crewmember later told investigators he did not believe the radios were charging the day of the fire.
Investigators identified the two different types of chargers among the soot and ash on the bridge. They also found battery remnants.
“Of the remains of the two lithium-ion batteries on the communications table, two cells from the same battery were found among the charger remains and had sustained fire damage,” the report said. “Although investigators found components of the second lithium-ion battery among the charger remains, its two cells were not found.”
Authorities believe the cells “probably burned in the fire.”