The blaze broke out at around 5:45 Thursday morning inside the Inolex Chemical Company facility at Jackson and Swanson streets.
Firefighters responded quickly to reports that the flames were near the facility's reactor.
Fire investigators say there were no toxic chemicals involved.
The flames were contained to insulation in one of the areas of the building.
Officials say the rest of the plant was secure throughout the fire.
There are no reports of injuries and no word yet on a cause.
