A family of seven was saved by their carbon monoxide detectors Thursday morning in west suburban Cicero.

The family was alerted by the detectors to extremely high levels of carbon monoxide in its home, with four of the seven being transported to MacNeal Hospital in Berwyn for a health evaluation, the Town of Cicero said in a statement. The other three family members declined treatment.

Cicero Fire Chief Dominick Buscemi said carbon monoxide levels in the home were very high, but that the detectors let the family know of the threat immediately.

“There could have been seven casualties if the residents had not installed carbon monoxide fire detectors in their home,” Buscemi said.

The family’s detectors were among those donated annually to residents by the Town of Cicero, the statement said.