港毒

 A gas chamber (毒氣室) is an apparatus for killing humans or other animals with gas, consisting of a sealed chamber into which a poisonous or asphyxiant gas is introduced. Poisonous agents used include hydrogen cyanide (氰化氫), carbon dioxide and carbon monoxide(一氧化碳)

https://en.m.wikipedia.org/wiki/Gas_chamber

Some cigarette smoke components, such as carbon monoxide (CO一氧化碳) hydrogen cyanide (HCN 氰化氫), and nitrogen oxides, are gases. Others, such as formaldehyde, acrolein, benzene, and certain N-nitrosamines, are volatile chemicals contained in the liquid- vapor portion of the smoke aerosol.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://cancercontrol.cancer.gov/brp/tcrb/monographs/7/m7_5.pdf&ved=2ahUKEwjs_MnfyqvtAhVUyosBHRnGCJIQFjABegQIARAF&usg=AOvVaw0i9nO8t4DmDaDCEehDbmGN

氰化氫 (hydrogen cyanide)，又稱氫氰酸，化學式HCN，相當擬鹵素氰的擬鹵化氫。標準狀態下為液體，劇毒且致命(very toxic and deadly)，無色而苦，並有淡淡的杏仁氣味，能否嗅出視乎個人基因。

https://zh.m.wikipedia.org/zh-tw/氰化氢

Carbon monoxide(一氧化碳) is harmful when breathed because it displaces oxygen in the blood and deprives the heart, brain and other vital organs of oxygen(缺氧). Large amounts of CO can overcome you in minutes without warning — causing you to lose consciousness (失去知覺)and suffocate(窒息).

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.osha.gov/OshDoc/data_General_Facts/carbonmonoxide-factsheet.pdf&ved=2ahUKEwjYioL3zqvtAhUyCqYKHbf5D6MQFjAMegQIJxAF&usg=AOvVaw0srPzu-JZ15Pc8CHTqHQ3n