The derailment that caused a freight train to catch fire and spill oil at a scientifically important site is not thought to have been caused by criminal activity, police have said.
Ten wagons, each containing 75 tonnes of diesel, derailed and spilled oil into the Loughor Estuary near Llanelli in Carmarthenshire on Wednesday night.
An investigation has started into the derailment as the clean-up begins.
British Transport Police’s initial probe has ruled out criminal intent.
“Initial findings are that the derailment is not believed to have been caused by criminal activity,” said Det Ch Insp Paul Langley.
- Up to 750 tonnes of oil in derailed wagons
- Diesel spill after train derails catching fire
“We are therefore handing primacy of the scene to the Office of Rail and Road, so that it can carry out its own specialist investigation.”
It took fire crews 33 hours to put out the blaze after the freight train carrying 25 tank wagons of Puma Energy’s diesel between Pembrokeshire to Theale, near Reading in Berkshire, derailed at 23:20 BST on Wednesday.
The subsequent fire led to 300 people in the area surrounding the crash site being evacuated from their homes, before being allowed to return on Thursday.
The driver and engineer of the DB Cargo train escaped unhurt.
The Rail Accident Investigation Branch is examining the cause of the crash.
Natural Resources Wales (NRW) is overseeing the clean-up and assessment of the impact on local wildlife at the adjacent site of special scientific interest, which is home to wildfowl and wading birds.