SaferProducts incident

Failure type

Fire / ignition

Incident narrative

SaferProducts.gov consumer incident report 20260815-2BEC6-2147312399. Severity: Incident, No Injury. Product: First Alert SMCO600NV-AC (Product name: First Alert SC5 Smart Smoke & Carbon Monoxide Alarm, hardwire Manufacturer: Resideo Technologies, Inc. (First Alert brand) Model number: SMCO600NV-AC (retail SKU FSMCO600NVACCL1)). Incident: Three First Alert SC5 hardwired smoke and carbon monoxide alarms were installed in a three-level single-family dwelling in July 2025, replacing expiring [REDACTED] units. Over the following thirteen months two of the three produced repeated false smoke alarms at least 31 smoke notifications and 8 full alarm activations, none corresponding to any fire, smoke or hazardous condition. The safety risk is twofold. First, the alarms cannot reliably be silenced. On two separate occasions, under two different interconnect configurations, an activated SC5 could not be silenced by any means available to a person physically present. On both occasions the only way to stop the alarm was to take the units down from the ceiling and remove their batteries. The second occasion, on July 28, 2026, involved a neighbour attending an unoccupied property who had to dismantle all three units. As a direct result the dwelling was left with no functioning smoke or carbon monoxide detection on any of its three levels for a period. A life-safety device that can only be stopped by dismantling it compels its own disablement, which is the recognised pathway to fatal outcomes in residential fires. Second, one unit shows evidence of an abrupt sensor or signal-processing fault. The SC5 issues a "Heads-Up Smoke Warning" when obscuration is rising, ahead of full alarm. The second-floor unit produced three full alarms January 16, January 17 and July 12, 2026 with no preceding warning on any occasion. Smoke does not appear instantaneously. A device that transitions from quiescent to full alarm without detecting a