Downtown Fort Worth was rocked by a massive explosion at the W.T. Waggoner Building, at 810 Houston St., on January 8 at about 3:30 pm, blowing out the two bottom floors and causing injuries to 21 people, according to NBC 5.

The building was recently remodeled as the Sandman Signature Fort Worth Hotel, which opened in March 2023. According to the hotel, 26 rooms were occupied when the explosion occurred.

Downtown workers and residents said they heard what sounded like thunder before spying billowing smoke and people running through the parking lot of the hotel. A raft of emergency vehicles convened, and trains into downtown stopped running. Some shot videos of the aftermath, showing massive piles of debris on the street.

The explosion is believed to have been caused by a natural gas leak, according to the ATF and Fort Worth Fire Department, who said that construction was taking place on a basement-level restaurant, and that a gas leak had been detected at the building but it was unclear if it was the cause of the explosion.

Craig Trojacek of the Fort Worth Fire Department told NBC that they'd be investigating if gas was the cause, as well as assess the stability of the building.

The hotel issued a statement, saying that "emergency responders are onsite and we are working closely with the authorities to understand the origin of the event and the extent of the harm caused. The safety and well-being of our team members and guests is our priority. We are working with those who have been injured to fully support them at this time."

Of the 21 people injured, one was in critical condition, four were in serious condition, and 14 had minor injuries.

The 20-story W.T. Waggoner Building was built in 1920, and was one of the tallest buildings in the area at that time. It's listed on the National Register of Historic Places and prior to the hotel renovation was used as office space by XTO Energy.

The hotel is also home to Asian restaurant Musume, which was not open at the time of the explosion. Three employees were injured and were taken to the hospital.

UPDATE 1-12-2024: An investigation by Atmos Energy determined that its system was not at fault in the January 8th incident.

While natural gas was involved, The Fort Worth Fire Department confirms that the explosion was not triggered from outside of the structure, and is transitioning its focus to inside the structure.

“Although this is still in the early stages of the investigation, this is a significant development and provides us the ability to focus on a smaller footprint in order to try and determine a cause of this tragic event for all involved,” stated Fire Chief Jim Davis.