This is the dramatic moment a firefighter narrowly escaped an explosion while responding to a burning building in Arizona.

The Tucson Fire Department received a call about a blaze in the 3100 block of East 22nd Street on May 24 afternoon.

Upon arrival, crews found thick smoke billowing from the rear of the building.

A full alarm was raised, and firefighters began searching for the source of the blaze.

Footage shows a worker retrieving bolt cutters from a truck compartment and approaching the structure.

Moments later, it suddenly exploded, sending a massive cloud of smoke into the air.

Nearby responders were seen fleeing the blast, with one firefighter losing his footing and tumbling onto the roadside while sprinting to safety.

Following the blast, crews shifted to defensive operations as it was no longer safe to enter and extinguish remaining hotspots.

Some firefighters were reportedly on the roof when it gave way, but were not injured in the incident.

Excavators were later deployed to demolish the unstable structure.

A police investigation revealed that the fire was caused by homeless activity inside the building.