Millions of combination smoke and carbon monoxide detectors have been recalled due to a potential alarm failure. 

The 3.5 million smoke and carbon monoxide alarms affected are the 'Kidde Nighthawk' models manufactured from June, 04 - Dec, '10

Kidde has pulled the affected models over concerns the battery life alert sound won't 'chirp' to let you know it needs replacement.

“The alarm can fail to continue to chirp when it reaches its seven year end of life if the batteries are replaced, leading consumers to believe it is still working,” the Consumer Product Safety Commission said. “This poses a risk of consumers not being alerted to a fire or CO incident in their home.”

Consumers should immediately stop using the recalled alarms and contact Kidde for a replacement.

credit CPSC