# False CO Alarms Triggered by Hydrogen‑Inhalation Devices — Root‑Cause Analysis
Some customers may wonder why their carbon‑monoxide alarm goes off when using a hydrogen‑inhalation machine.
To clarify: The hydrogen‑inhalation machine itself does not generate carbon monoxide. This is a false alarm and there is no real carbon‑monoxide safety hazard.
Most household carbon‑monoxide alarms adopt electrochemical sensors. Such sensors have cross‑sensitivity: hydrogen gas interferes with the sensors. The sensors cannot tell hydrogen apart from carbon monoxide, which results in false triggering.
Recommended safety practices:
Ensure good ventilation during operation to facilitate gas dispersion Use an extended nasal cannula and place the hydrogen‑inhalation machine further away from the carbon‑monoxide alarm in a well‑ventilated location