PORTLAND, Ore. --

Portland firefighters were called to a tank explosion near the Portland Expo Center on Friday.

The explosion was first reported at 12:05 p.m. on North Force Avenue. By 12:45 p.m., the fire was recalled.

Witnesses said they heard an explosion and saw flames 20 to 30 feet high.

Firefighters called in a second alarm before they reached the scene, when they saw the columns of black smoke billowing up.

The fire burned around tanks of recycled oil, near the Portland Expo Center and Heron Lakes Golf Course in north Portland.

The owner of the oil recovery company said workers were filling a fuel tank, when some of the liquid and vapors escaped, spilled, and then caught fire. No one was hurt.

Workers evacuated the oil re-refining company property, while firefighters worked to knock down the flames and police closed streets in a half-mile radius from the scene until the flames were out.

The oil inside the bigger tanks didn't catch fire, but some of the insulation around the tanks burned.

"A huge explosion went off. It was just almost instantaneous. I went over and looked out the window and 20, 30, 40 foot wall of flame out there," said Matt Coale the owner of a neighboring business.

Firefighters said the oil and the water used to extinguish the flames were contained to the immediate area and didn't cause environmental damage.

Copyright 2009 by KPTV.com. All rights reserved.This material may not be published, broadcast, rewritten or redistributed.