Nest Topaz-2.7

SaferProducts.gov consumer incident report 20231203-30561-2147343674. Severity: Incident, No Injury. Product: Nest Topaz-2.7 (Nest Protect Smoke/CO Detector). Incident: Nest Protect Smoke/CO detectors did not raise an alarm during a smoke event. Had a fire in the fireplace going for about an hour when some pressure changes caused the HVAC to draw smoke into the entire first floor and it eventually made its way up to the center staircase to the second-floor landing. I had to turn off the HVAC and open windows to air out smoke that was clearly seen floating under lamp lights. Nest Smoke/CO detectors next to the kitchen and in the upstairs landing remained silent during the event. The Nest application did not register a smoke event, but it clearly showed motion activity when it turned on the night light feature. The application reported "Everything is ok!" during this event. These are wired powered smoke/CO detectors manufactured in 2018 with an expiration date of 2028. I tested the back-up batteries and they were good. I'm currently working with Nest to determine why these have failed to perform their designed task. I no longer have confidence in the Nest detectors (do they even detect CO? how do I test *that*?)