Fire broke through the roof of a waste treatment plant in St. Paul Tuesday morning following a small explosion that left one worker injured.
KARE 11 reports that fire crews "spent hours" battling a fire inside a Metropolitan Council building on 2400 Childs Road, which sparked shortly before 10 a.m. and caused "thick black smoke" to pour through windows.
One employee at the plant was initially unaccounted for, according to the St. Paul Fire Department, but they were later found safe in an area of the building.
The fire is believed to have started by a contractor using a saw, creating sparks as he cut into odor-fighting equipment.
This man was hurt in the fire, during the course of which there was a "small blast" according to the Star Tribune. He was taken to Regions Hospital for treatment on minor injuries.
The building was in the process of being demolished when the fire started, and the blaze was at one point so intense it forced firefighters to battle it from outside.
It was brought under control before noon, with crews dousing the remaining hot spots before packing up.