GUN BARREL CITY, Texas (KETK) – Gun Barrel City Police Department and Gun Barrel City Fire Department responded to a possible carbon monoxide poisoning on the 100 block of Garret Lane that left one dead on Saturday.

After arriving to the scene officers and firefighters said they found a three-year-old female child, a four-year-old male child, a six-year-old male child and the children’s 28-year-old mother. They immediately began trying to save their lives and they were all then transported to UT Health Texas Cedar Creek Lake.

The six-year-old male child was unresponsive when they arrived and later died, according to officials.

The Henderson County Sheriff’s Office said, the woman left the hospital against medical advice to go with her children, who were transferred to a hospital in Dallas. Law enforcement had previously said she was expected to recover.

The Gun Barrel Fire Department said the carbon monoxide levels at the house were more than 800 ppm and anything over 100 ppm is considered a fatal level.

Officials said they found a a generator inside the bedroom, and it had been on all night. The stepfather found the four victims and called first responders, according to authorities.

One of the children is in critical but stable condition while the other is in stable condition.

Officials said that the Henderson County Crimes Against Children Taskforce is investigating the incident with Gun Barrel City Police Department. Law enforcement said the case could possibly be filed with the Henderson County District Attorney’s Office.