Kidde is recalling combination smoke and carbon monoxide detectors. The recall includes Kidde Nighthawk combination smoke and CO detectors. The alarms in these detectors can fail to chirp, thus not alerting owners when the detector has reached its seven-year end of life and needs to be replaced. The detector can fail to alert owners to the end of the device's life if the batteries are replaced. Homeowners could believe that their detectors are still working properly when, in actuality, they are not.