Six youngsters were taken to hospital when scaffolding around a derelict pub they were playing on collapsed.
Firefighters from across Lancashire, including crews from Bamber Bridge and Chorley, were called to the incident last night at the former Duke of Edinburgh pub in Crabtree Street, Blackburn.
Two teams of specialist search dogs were also called in from both Lancashire and Greater Manchester Fire Services to scour the rubble for other victims.
But later a police spokesman said everyone had been accounted for and none of the youngsters had been seriously hurt.
“It’s fortunate that they weren’t more seriously injured or killed,” he said. “They were very lucky.”
It is believed the teenagers, all boys, were playing on scaffolding and also inside the disused building when it collapsed.
Firefighters from across the county raced to the scemne, some with specialist rescue equipment, because it was feared there may be other casualties under the rubble. But the site was given the all-clear after a thorough search.
A multi-agency investigation has been launched into what caused the collapse.