A massive Beach Boulevard blaze that engulfed a Southside Jacksonville building Thursday was accidentally ignited by welding work, a representative with the state Fire Marshal's Office said Friday.

Lt. Robby Stephens said the fire, which decimated a building in the 4900 block of Beach Boulevard that housed Jaguar Builders and Accessibility Specialists, was started by an employee using arc-welding equipment.

Toni Mettles, an office manager with Jaguar Builders, said Accessibility Specialists converted vans to make them wheelchair-accessible. The embers from the welding started the fire, Stephens said, and a warehouse connected to the building that contained paper records caused it to quickly flare up.

Stephens said the investigators verified the cause with surveillance footage taken from the building.

Two employees were in the building when the blaze caught. One man in his 40s was taken to a hospital for observation. About 90 firefighters and almost 30 fire department vehicles were required to take down the three-alarm inferno.

Matt Coleman- Jacksonville.com