Altering the good manager's alleged comment:
"Basil for our street has admitted that people can be 'incapacitated' by toxic fumes in houses."
Especially if there's a gas leak, fire, CO from a gas appliance, cleaning fluids used without ventilation etc etc.
The CC smoke hoods are just that; to assist CC to remain effective in case of fire.
It seems to me that a small group of people appear to be determined to make an issue of a vanishingly unlikely event.