Drivers are being warned to avoid the A19 around Thirsk after a lorry exploded on the carriageway.
Officers were called at around 9.45am today after reports that a load of hay bales had caught fire on the back of a wagon.
The vehicle is on fire on a bridge over the A19 and flaming debris is falling onto the carriageway below.
The road is closed in both directions as emergency services deal with the fire.
Traffic is currently being diverted through Thirsk.
The driver of the vehicle was not injured in the incident.