Khandro: "I wonder if some people have ever been without anything in their entire lives - perhaps communism is the answer? "
They have been without communism, for sure.
"They use carbon dioxide in the stun guns in slaughter houses. They also use carbon dioxide when packing foodstuff to extend the shelf life."
The UK gas concentration chambers use carbon dioxide in human slaughtering:
"Pigs are lowered, preferably in groups, into a chamber containing a minimum concentration of 70% carbon dioxide in air. The pigs then lose consciousness and must remain in the gas mixture until dead."
(Carbon dioxide is also used in some fishy slaughtering.)
https://www.hsa.org.uk/faqs/general