GATESVILLE (CBSDFW.COM) – A deadly explosion rocked a hospital near Waco at about 2:15 p.m. on Tuesday, and two of the victims are recovering in North Texas. The blast happened at Coryell Memorial Hospital in Gatesville, in a construction zone near the back of the facility.

The explosion sent debris and smoke flying into the air.

Officials with the hospital said that a boiler room underneath the construction site may have been involved, or a gas line in the ground. Investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives were at the scene through Tuesday evening to inspect the damage.

The construction project began in November 2016.

Coryell Memorial Hospital is a 25-bed county facility. The hospital was being expanded, and part of the building collapsed in the blast. One construction worker was killed in this incident, and another 12 victims were injured. There were no hospital staff members or patients involved in the explosion.

The hospital building and a nearby nursing home were evacuated after the incident took place.

Two of the injured construction workers were flown from the blast site in Gatesville to Parkland Hospital in Dallas, to receive treatment from specialists in the burn center. A family member to one of those men said that her stepfather has burns over 40 percent of his body — third-degree burns on his arms and hands.

Dr. Brett Arnoldo is a burn specialist at Parkland Hospital. “The thing to keep in mind is that a burn injury is a monumental event for the patient, because the skin is the largest organ in the body. Take into consideration, this is a very complicated injury,” he said. “You have to, ultimately, get all of the skin that’s dead, that’s burned, off.”

Nine of the victims were taken to a hospital in Temple. A doctor there said that most of the patients had burns to the entire face, ears, nose and mouth area. Many of them also had burns to their hands — both front and back. Dr. Justin Regner with Baylor Scott & White Hospital said, “It was fairly impressive how close these individuals were to the heat.”

The hospital remains without power on Wednesday. All patients were tranferred to other facilities.

Jennifer Lindgren