At around 23:15 on 26 August 2020, the 21:52 DB Cargo service from Robeston Oil Refinery, Milford Haven, Pembrokeshire, to Theale Oil Terminal, near Reading, derailed on the Up District line near Llangennech in Carmarthenshire.
The train was made up of 25 tank wagons, each containing up to 75.5 tonnes of diesel or gas oil. Ten of the wagons (3rd to 12th in the consist) derailed, causing a major spillage and a fire.
The driver, who was unhurt, reported the accident to the signaller whereupon the fire was tackled by the fire service, who ordered the evacuation of local residents due to concerns for their safety. Local people have reported seeing a plume of flames and smoke, and the strong smell of fuel.
The Rail Accident Investigation Branch has launched an investigation into the causes of the derailment and will report in due course.