What's up, my friend? I'd like to run something by you. Being in or of the Commonwealth nations, do you suppose you share common laws, similar to this one? When we combine the real facts and real science with malicious intent, and a whole host of other misdeeds, the potential for a landslide of lawsuits seems imminent. I've roughtly sewn some bits together, here.

Canadian Criminal Law/Offences/Assault Causing Bodily Harm
https://en.wikibooks.org/wiki/Canadian_Criminal_Law/Offences/Assault_Causing_Bodily_Harm
Legislation

1. Every one who, in committing an assault,
   (a) carries, uses or threatens to use a weapon or an imitation thereof, or
   (b) causes bodily harm to the complainant,
   is guilty of an indictable offence and liable to imprisonment for a term not exceeding ten years or an offence punishable on summary conviction and liable to imprisonment for a term not exceeding eighteen months.

Proof of Offence

1. seriousness of injuries:
2. a hurt or injury interfered with the victim's health or comfort and whether it was "more than merely transient or trifling in nature"

From https://www.ccohs.ca/oshanswers/chemicals/chem_profiles/carbon_dioxide.html
Mild Exposure
Carbon dioxide is present in natural air at a quantity of approximately 0.035 percent. When you are exposed to a low level of carbon dioxide, around 1.5 percent, you will begin having physical and mental issues. But it can be difficult for you to figure out what is going on. The initial symptoms include dizziness and a change in breathing.

Over time, performance levels will decrease, and erratic, abnormal behavior will set in.
[It makes a person insane!]

This only refers to external CO2 levels, not even mentioning the harm of acidosis, low O2 levels, etc... In summary, there is a LOT to work with, should a few honest blokes care to do the honourable thing. Stroke and MI's gonna go thru the roof!