Wrong mixture of common cleaning supplies produced chlorine gas?
Bleach, ammonia, acids.
Chlorine gas from chemicals is rather obnoxious and these people seem to have been taken unaware.
Carbon Monoxide poisoning maybe?
Bleach and lye --> chlorine gas?
Your right on....I have heard of people mixing 2 different chemicals to clean toilets and died from the gas’s released. Got to be careful with glues also...I do crafts and accidently used two different glue’s and you could see the chemical reaction that floated up into to the air...never made that mistake again...