Motorists were left "at a standstill" on the A19 after an oil spill sparked "severe" delays.
Emergency services were called to the northbound route of the major road on Tuesday before 3pm after a liquid spillage between the Norton and Wynyard turn-off.
The road was closed between the two junctions, with motorists urged to avoid the area while the clean-up operation got underway.
Pictures from the scene showed miles of queueing traffic, which stretched past the A19 flyover and at the road's junction with the A66.
Eyewitnesses reported seeing traffic "backed up for miles" - with AA Traffic News reporting "severe" delays throughout the afternoon with an average speed of 10mph.
The A689 Wynyard turnoff and the A1027 Norton turnoff both also saw some delays on nearby roads as motorists were diverted off the A19.
While Cleveland Police only confirmed it was a liquid spillage, traffic site Inrix said it was oil that had spilled onto the road, prompting the closure.
The road was re-opened by 4pm.
Cleveland Police previously said: "Motorists are advised of a full road closure on the A19 Northbound from the A1027 Norton turn off to the A689 Hartlepool/Wynyard turnoff.
"There is a liquid spillage on the carriageway and work is underway to remove it safely.
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"Police and colleagues from Cleveland Fire Brigade and Highways England remain on scene and we ask drivers to seek alternative routes.
"We appreciate your co-operation and understanding."
The Northern Echo has contacted Cleveland Fire Brigade and the force for more information.
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