An explosion occurred at a construction site at Coryell Memorial Hospital around 2:15pm on Tuesday (local time), hospital officials said.
The person who died and the 12 people injured were construction workers, officials said. Seven of them are in critical condition.
The construction crew was working on a hospital expansion project at the time, the hospital's CEO David Byrom said.
No hospitals staff or patients were injured in the blast, hospital officials said. Crews evacuated all patients.
Officials are still investigating what caused the explosion. Byrom suggested it may have been related to a gas line.
"It could be some time before we understand what occurred there. ... It was quite a blast," Byrom said.
The under-construction area where the explosion occurred is "extremely damaged," and other parts of the hospital have some damage "that appear related to a shockwave when the blast occurred," he said.
The hospital contains a nursing home, which was partially damaged, Byrom said. The home's residents have been temporarily relocated to other facilities and nearby churches.
Officials said they will release the name of the person who died after they contact that person's family.
The majority of the victims had second- and third-degree burns after the explosion, according to officials at Baylor Scott & White Medical Center in Temple, the facility that treated most of those injured.
The hospital is currently closed, and Byrom said he was unsure when they would reopen.
Two Austin public safety agencies sent resources to Gatesville in response to a state request for help.
Austin-Travis County EMS sent five ambulances, one ambulance bus, one division chief and a district commander. The Austin Fire Department sent three trucks, one battalion chief and 10 "structural collapse" techs.
About 900 nearby homes and businesses lost power after the blast, according to KWKT-TV.
