The National Transportation Safety Board (NTSB) is warning crews about the dangers of unsupervised charging of lithium-ion batteries following an investigation into a fire on the oil tanker, S Trust. The fire, which occurred while the vessel was docked in Louisiana, was attributed to a lithium-ion battery-powered radio left in a charger on the unattended bridge. The explosion of the battery caused a fire that destroyed the navigation, communication, and alarm systems on the bridge. The NTSB recommends avoiding unsupervised charging of such batteries, keeping batteries and chargers away from heat sources, and disposing of damaged batteries properly.