Three people have been seriously injured in the suspected gas explosion.
Cumbria Police said emergency services were called to an address on Hew Street in Whitehaven at 16:23 GMT.
The force confirmed that two men and a woman were taken to hospital with serious injuries.
Whitehaven councilor Joseph Ghayoba, who represents Branste ward, told BBC Radio Cumbria that the “tight-knit” community was in “shock” but was rallying to support those affected.
He said: “I have been inundated with messages from residents offering places to spend the evening if they have nowhere to go, people offering blankets and clothes and places to stay for the night.
“The community is really stepping up.”
Crews from Cumbria Fire and Rescue and North West Ambulance Service are at the scene, along with engineers from Northern Gas Networks (NGN).
Emergency services are urging people to stay away from the area.
He also said that “all known persons” had been accounted for but work was “ongoing” to verify this.