Kidde announced the recall of almost 500,000 dual-sensor smoke detectors in the U.S. and Canada Wednesday because a manufacturing malfunction can compromise the devices’ ability to detect smoke.

The recall was issued by the United States Consumer Product Safety Commission and includes more than 450,000 smoke alarms in the United States.

A yellow cap that was left on during manufacturing can cover one of the two smoke sensors, posing a risk of people not being alerted to a fire in their home.

Dual-sensor smoke detectors use photoelectric and ionization technology to detect both smoldering and fast-moving fires.

Both recalled models—the Kidde PI2010 and Kidde PI9010—performed very well in CR’s tests. During our testing we did not encounter the problem for which the detectors were recalled.