Fire destroyed an apartment building with about 90 units that was under construction in Vancouver.

Fire destroyed an apartment building with about 90 units that was under construction in Vancouver.

The fire broke out about 3:30 a.m. Friday and went to two-alarms as it brought the four-story structure to the ground.

Fire Marshal Heidi Scarpelli told KOIN (http://bit.ly/1w2JApM ) flames forced firefighters to take a “defensive approach,” pouring on water from outside.

Natural gas helped fuel the flames until a utility crew shut off the line.

There are no reported injuries.

Scarpelli says investigators looking for the cause of the fire will likely bring in a dog trained to detect any accelerants. She also says investigators may ask for assistance from the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Witnesses told KATU (http://bit.ly/1lb1zHl ) they heard an explosion and saw the sky turned orange.