The Nashville Fire Department said a compromised gas line near a mechanical room caused the explosion just after 8 p.m.
"There was an area on the Delta, near a mechanical room, where an explosion occurred," Deputy Fire Chief Kim Lawson explained. "There was no fire. Crews went inside. There is some damage to that area. Crews were immediately called [to shut off] off utilities."
No hotel guest rooms were affected. All guests and Gaylord employees were safely evacuated and no one was injured.
The Nashville Fire Department, Metro police and structural engineers worked through the night to assess the damages and ensure the integrity of the property before allowing everyone to reenter shortly after 3 a.m.
The hotel and restaurants resumed normal operations at 7 a.m.
The explosion caused significant damage to an escalator, walls and the ceiling.
Hotel officials said initial damage estimates are around $750,000 and repairs are underway.
The affected areas of the Delta Atrium are closed off.
The blast will have little to no effect on upcoming meetings and events at the hotel, officials said.
"I want to commend the efforts of the Nashville Fire Department, Nashville Police Department, and our [staff] for their swift response that ensured that the issue was assessed as quickly as possible and that all guests were safely evacuated," Gaylord CEO Colin Reed said in a statement released Wednesday morning. "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."
A witness reported to Nashville's News 2 he was exiting an elevator around 8:15 p.m. when he saw ceiling tiles falling due to the explosion.
"We turned the corner right near the convention center entrance [and] ceiling tiles were falling out [and there was] several large holes [and] debris all over the place," Steve Boyer said.
Boyer was among 4,500 law enforcement officers staying at the hotel for the National Sheriff's Conference.
Steve Moore said he was in his room when the emergency alarm sounded.
"The alarm woke me up and it's loud in the room. It said an emergency has been declared. Do not use the elevators," he recalled.
Incoming President of the National Sheriff's Association, Sheriff Larry Amerson, characterized the incident as a "large explosion." He reported at least two floors were damaged.
Motor coaches were brought to the hotel to transport guests to the nearby Grand Ole Opry House. A second building on the hotel's grounds was also opened for guests.
A spokesperson said guests were provided with cots and blankets. Many others planned to stay at other hotels.
A group of guests from London told Nashville's News 2 they needed their passports in their room for a morning flight.
The investigation into the explosion is ongoing.
The Federal Bureau of Investigation and the Bureau of Alcohol Tobacco, Firearms and Explosives are assisting.
Guests said, other than the closed off area, the rest of the hotel seemed to be back to normal.
"Fortunately we got back in and I was able to get to sleep around five this morning," Fairfield County, Ohio Sheriff Dave Phalen said.
Phalen and his wife were at the hotel for the National Sheriff's Assocation Convention.
"When we were on our way in from the pool yesterday, I mentioned to my husband I really smelled a strong smell of gas," Sheriff Phalen's wife Loretta said. "So I said wouldn't it be something if this place exploded.
She continued, "Then that all went off and I said I shouldn't have said that."
Others initially thought the explosion may have been intentional because of the number of law enforcement officers at the hotel at one time.
"I thought it was terrorist trying to kill us all right away," U.S. Marshall Louie McKinney said. "I said I am getting out of here."
McKinney said the explosion was not minor as officials have described.
"It was a big like an earthquake." he said. "The building was shaking."
The National Sheriff's Association Convention cancelled all of its workshops and the expo for the day, but relocated the scheduled closing banquet.
Intead of it taking place in the Delta area it will be in the Governor's Ballroom at 6 p.m.
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