The Tracy Fire Department responded to a house explosion Saturday morning that critically injured a mother and her three children.
Witnesses say the explosion blew the chimney off the roof and sent glass flying across the street.
Neighbors ran to rescue Sonja Timmons and her children after the blast. One man ran into the home to rescue Timmons' 2-month-old baby. The family was taken to a local hospital and then flown to the burn unit at Regions Hospital.
Investigators are still looking onto what caused the explosion, but when crews arrived at the home on Elm Street, it was fully engulfed in flames.
Troy Haugen told FOX 9 News that the explosion happened when Timmons, his fiancee, lit a cigarette. Though investigators are looking into gas problems in the home as a cause, Haugen said Timmons did not smell gas or feel unwell prior to the explosion.
Timmons was still in critical condition as of Sunday afternoon.
"Thank you for your prayers and support during this difficult time," Haugen said in a statement. "I would also like tot hank the medical staff at Regions Hospital who are caring for Sonja. I am confident she is getting the best care possible."
Haugen said Timmons and her children are expected to recover; however, Timmons and her oldest child will probably be in the hospital for at least two months while they receive burn treatments and skin grafts.