The road has been closed in both directions near to the Fishbourne Lane on the outskirts of Ryde following a fire near to the entrance of Quarr Abbey.
An Isle of Wight Radio listener reported that the issue emanated from a fire on a bus, which saw passengers evacuated this morning (Tuesday).
Traffic is backed up from Wootton to Havenstreet, with drivers strongly advised to avoid the area.
We have contacted the emergency services for further information.
UPDATE 12.45pm
A spokesperson for the Hampshire and Isle of Wight Fire Service said:
"Ryde and Newport crews were alerted to an incident on Quarr Road in Binstead shortly before midday.
"It was initially reported to be a bus fire, but upon arrival crews found the alarm to have been caused by an engine coolant leak.
"Crews managed the traffic as firefighters worked to stem the leak and clear up the spillage.
"The stop message came in at 12:42pm."