Firefighter Rene Fernandez's facepiece slipped off as he attacked the fire, causing him to suffer smoke inhalation, Fire Chief Jack Collier told Firehouse.com.
Fernandez was transported to Scott & White Hospital in Temple and remains in the ICU.
The five-year veteran suffered sores and burns to his mouth and throat and has been intubated. He is expected to be hospitalized for anywhere from 24 to 72 hours.
"I think he's going to be OK. The hospital is just being over cautious to make sure he is OK," Collier said.
Crews responded to the fire at the older model mobile home at the corner of Amy Lane and Beeline Lane at approximately 8:15 a.m. in what started out as a routine call.
"In this business we tend to take the routine fires for granted and that is exactly what this was," the chief said.
Upon arrival, firefighters determined all occupants were out of the structure and decided to initiate a defensive attack as it was already fully involved.
The initial attack team went up to the trailer to apply water to the fire through the open doorway, but strong winds changed the direction of the flames.
"It brought the fire right down on them," he said.
The firefighters were all in full turnout gear and PPE, but Fernandez's regulator and mask somehow became dislodged and he inhaled the smoke and superheated air.
"As long as he doesn't have any complications, I expect him to be out of there by this time tomorrow," Collier said. "We're just saying a prayer and are going to be there to do whatever we can to help him."
He said he is planning to conduct an investigation into why Fernandez's mask came off.
Firehouse.com will provide more information on this story as it becomes available.