A towering fire broke out in an apartment complex on Woodbury's northwest side early Monday morning, spewing 40-foot flames into the air before firefighters could contain it, authorities said.

Several people were displaced, but no injuries were reported.

Firefighters from the city's four firehouses — in addition to crews from Oakdale and Cottage Grove — were called to the scene just after 1 a.m. and extinguished the blaze in 45 minutes, said Woodbury fire service commander John Wallgren.

The cause of the blaze, which is believed to have started on the "second floor deck area," did not appear to be suspicious, Wallgren said.

The likely culprit, he said, was a discarded cigarette or match.

Wallgren said that neighbors awoke to "some sort of explosion and three apartments were on fire."

"We think the explosion wasn't so much of an explosion as the superheat shattering the patio doors," he said.

By the time firefighters arrived, the fire had apparently been burning for several hours and its orange glow could be seen from several miles away, he said, adding that 30- or 40-foot flames were shooting up from the sides of the three-story building.

"The fire was on the outside of the building, so the detectors aren't going to pick those up," he said.

Smoke, water and fire damage made six apartments uninhabitable. The Red Cross provided assistance to the displaced residents.

Libor Jany • 651-925-5033 Twitter:@StribJany