Milwaukee, WI – The Milwaukee Fire Department said a dozen people, including children, were taken to the hospital this morning because of carbon monoxide poisoning.

The department said firefighters responded to the duplex on the city’s northwest side at about 4:15 a.m., when one of the people inside woke up sick, alerted others and called for help.

Battalion Chief Michael Payne said the situation could have been much worse had no one called for help.

He said ambulance personnel were alerted to the symptoms and suspected carbon monoxide poisoning immediately.

Payne said everyone in the home fell ill — including three adults, and children and teens ranging in age from 12 to 18. But he said there was a one-year-old in the home as well.

Officials said they suspect a furnace caused the poisoning.

Payne said the home did not have a carbon monoxide detector.