"The whole building is like a tuna can, it is shredded," said a worker at Electronics for Imaging printing business.

EFI technician Dion Raglin said it was just a few minutes after employees first smelled gas Wednesday afternoon before the back of the building went boom.

Injuries unknown; firefighters remain at the scene.

Ice may have damaged a gas line, causing a Nashua, New Hampshire explosion. Now the fire department is issuing a warning about ice on roofs.

Crews are currently battling a large fire after a natural gas line exploded at a commercial building in Nashua, New Hampshire.