Officials said the explosion around 8:15 p.m. happened when natural gas got into a steam line inside a mechanical room near an elevator in the Delta atrium.
The hotel, which was fully booked, was evacuated as a precaution, including hundreds of sheriffs from around the country who were staying at the hotel for the 2012 National Sheriffs Association Conference.
Davidson County Sheriff Daron Hall, who was attending the conference, said it was frightening.
"My wife was with me and we were trying to get everyone out of the room, out of the hotel and of course elevators weren't working now. And gas or what smelled like gas and fumes and all sorts of debris was falling so we were located where you didn't want to be," Hall said.
Guests waited at the Grand Ole Opry House and the Gaylord Special Events Center. Many tried to sleep with blankets provided by the hotel.
Crews remained on the scene throughout the night to air out steam lines before allowing guests back inside around 3:15 a.m. Guests were not charged for the night.
Metro Police Captain Ken Walburn said no hotel guest rooms were affected, but it caused significant damage to an escalator, walls and the ceiling. Walburn said investigators ruled out any suspicious activity.
Initial estimates of the damages are less than $750,000 and repairs are underway, according to hotel officials.
The hotel and restaurants resumed normal operations on Wednesday morning, according to hotel officials. They said "initial assessments of the damage suggest that the impact will not be material and will have little to no effect on upcoming meetings and events."
The company carries business interruption and property insurance for explosion damage. Hotel officials said the Delta Atrium in the hotel would be blocked off while repairs are made.
A statement was released Wednesday morning from Colin V. Reed, Chairman and Chief Executive Officer of Gaylord Entertainment:
"First and foremost, what is important is that no one was hurt as a result of this incident. I want to commend the efforts of the Nashville Fire Department, Nashville Police Department, and our STARS for their swift response that ensured that the issue was assessed as quickly as possible and that all guests were safely evacuated. At this stage we can now focus on returning to business as usual and repairing the impacted areas of the property with minimal disruption to our guests."
(The Associated Press Contributed To This Report.)