A large concrete mixer has gone onto its side in the centre of Blackpool.
Police and ambulance services were called to George Street, behind Sainsbury's, just after noon.
Police have closed the road and remain at the scene.
A North West Ambulance Service spokesman said: "We were called at 12.03pm to Buchanan Street and George Street to reports of a road traffic collision involving a lorry. We have currently got an ambulance, a rapid response vehicle and a senior member of staff at the scene.
"All resources are still at the scene so we have not got any details of injuries."
A police spokesman said no casualties had been reported to them.