Capt. Ken Walburn of the Nashville Fire Department said the explosion occurred at around 8:15 p.m. in the convention center portion of the hotel away from guest rooms.
He said it appeared that a gas leak was ignited inside a mechanical room on the first floor, causing significant damage to an escalator, walls and ceiling. He said the blast was so strong it damaged ceiling tiles on the third floor of the convention center.
"It was amazing that no one was hurt," Walburn said.
The hotel sits next to the Grand Ole Opry House, the heart of Nashville's country music scene.
Hundreds of sheriffs from around the country were staying at the convention center for the 2012 National Sheriffs Association. Walburn said the cause of the fire was investigated by the state bomb and arson squad, along with FBI and the Alcohol, Tobacco, Firearms and Explosives, but suspicious activity was ruled out.
"That was initially part of the concern," he said. "We wanted to make sure, given the location and the convention, that it wasn't an act of terrorism."
Davidson County Sheriff Daron Hall, who was at the hotel for the sheriff's convention, told WSMV-TV they could feel the blast from the explosion and saw debris falling.
"The concussion coming from the explosion was something that I've never felt before. It was a pretty alarming thing to happen in the location where we were in, and then debris starts falling, the ceiling tiles, where we were," Hall said. "...And you could imagine the alarm when you've got federal government officials from D.C. here."
Walburn said the hotel brought in structural engineers to check the damage.
