SAN ANTONIO -- Seven members of a Northeast Side family, including a newborn, were hospitalized Thursday after they were poisoned by carbon monoxide inside their home.

The victims, including four children and three adults, were listed in stable condition at University Hospital.

Capt. Eddie Powell, of the San Antonio Fire Department, said the victims were lucky to be alive because a carbon monoxide monitor returned a reading of 100. A reading of 50 is enough to cause permanent brain damage. A reading of one or two is considered normal.

Powell said a faulty heater was to blame for the leak.

"People just need to make sure their heaters are burning clean blue flames and that the flutes are clear," Powell said. "So that it vents outside of the house."

Richard Calhoun, a neighbor, said one of the adults woke up feeling nauseous and was suffering from a headache and knew something was wrong when two of the children wouldn't wake up.

"He smelled something," Calhoun said. "The air was funny. He got his family out."

Calhoun said the incident was a wakeup call for him.

"(It) makes you worry," he said. "You've got to check stuff out."