Four people are in hospital and several structures have been destroyed after a fire broke out on the Songhees Nation near Victoria on Wednesday morning.

Emergency crews responded to reports of a structure fire in the 1200-block of Craigflower Road in View Royal, B.C., just before 6 a.m. PT, according to View Royal Fire Chief Paul Hurst.

Hurst said crews found four units fully engulfed in flames — a fifth-wheel trailer and three mobile homes.

Hurst said one person is being treated for cardiac issues and three others for smoke inhalation at Victoria General Hospital. He said there were several occupants in and around the buildings when crews arrived and 30 people were evacuated from surrounding homes.

Four ambulance units and 31 firefighters were dispatched to the scene, with additional support coming from fire departments in nearby Colwood and Esquimalt.

Propane tanks exploded at the scene before fire crews arrived. (Bridgette Watson/CBC News)

"It was defensive operations right off the bat because of downed power lines, and there were two propane tanks that were venting and hampering efforts initially," said Hurst.

Hurst said the fire probably started in one of the structures and rapidly spread to the others, burning undetected until propane tanks began exploding and caught people's attention.

Crews were able to save one affected house, but the four units are beyond repair. Hurst said six people have been displaced from their homes.

The fire closed traffic in both directions along Craigflower Street during Wednesday morning rush hour.

The cause of the fire is being investigated.