Gardaí were last night seeking the driver of an oil tanker who made off on foot when his vehicle overturned on the M7 Monasterevin bypass in Co Kildare, spilling its load during yesterday morning's rush hour.
While the truck was painted in the Shell livery, the multinational oil company said it did not own the vehicle.
"It was branded Shell but it does not belong to Shell or any of its companies," a London-based spokeswoman said.
Gardaí believe the truck was being used to transport laundered fuel at the time of the crash. They are working on the theory that it had been sprayed with Shell's colours and logo so as not to arouse suspicion as it carried its illicit load to its destination.
The vehicle and the fuel it was carrying, believed to be laundered diesel, were being examined and analysed last night.
Gardaí in Kildare have launched a joint investigation with officers from the Revenue's customs service.
Both have joined forces on previous investigations into oil-laundering operations in Border counties.
The spillage, which took place at around 8.40 a.m., resulted in the south-bound carriageway of the Monasterevin bypass being closed for much of yesterday afternoon for a clean-up operation.
It was closed between 2 p.m. and 6 p.m. to allow the truck to be lifted back on to its wheels and then moved from the scene.
The vehicle overturned on the grass verge but some of the fuel from the tanker spilled on to the road. The emergency services remained at the scene for most of yesterday.
Local sources said the driver jumped from the cab and fled the scene, despite having sustained head injuries.
He refused to stay at the scene for medical assistance.
The driver was described as being around 30 years old, 5 feet 10 inches, and of slim build. He was wearing dark clothing.
Although he fled the scene on foot, gardaí believe he may have been driven from the area in another vehicle.
Sources said the truck appeared to veer off the main road, which was wet at the time, and on to a grass verge before crashing on to its side and coming to rest halfway down a ditch. No other vehicle was involved.
Traffic travelling south on the bypass was diverted via Monasterevin town until around 6 p.m. when all diversions were lifted.
Traffic lights were switched off in the town and gardaí assisted traffic flow in an attempt to keep it moving as freely as possible.
AA Roadwatch reported no major delays on the route.