A suspicious substance that shut down part of the M1 on Tuesday may have been hydrochloric acid and could have been placed on the road intentionally, police said.
Police are appealing for information after the “highly corrosive” substance spread across two lanes of the southbound carriageway near Milton Keynes, causing more than 12 hours of delays for commuters in the East Midlands.
“The object has now been removed from the scene in a secure container but is still being analysed, however, we do know the substance is a highly corrosive material, possibly hydrochloric acid, which has reacted with another substance causing it to discharge on to lane one and lane two of the southbound carriageway,” said Inspector Scott Long of the Joint Roads Policing Unit for Thames Valley and Hampshire.
Mr Long said investigators were keeping an “open mind” as to how the substance was left at the scene, and said that while there was no evidence the incident was terror-related, it was currently being investigated as a possible offence “with intent to cause danger to other road users”.
Police, fire services and the Army bomb unit were called to the scene between junctions 14 and 15 of the motorway, after the object was found at 7.30am on Tuesday.
Aerial footage showed liquid and a yellow substance leaking out of a black bin liner on the hard shoulder, inspected by a bomb disposal robot.
Police apologised for the disturbance, which saw thousands of motorists stranded on the motorway with little information as to when they could go about their day.
Tim Mayer, a Conservative councillor from Coventry who was caught up in the delays, said communication from police was “appalling” but people had been trying to make the most of the free time.
“There’s a five-a-side football competition, a bit of rugby, a guy cycling up and down in the wrong direction,” he said of activity on the shut-down road.
Anyone with information has been urged to call 101 and quote reference number 138 for September 19.