Also the problem of expired tear gas, which will "breaks down into cyanide oxide, phosgenes and nitrogens that are extremely dangerous" according to a 2017 stud

Also the problem of expired tear gas, which will "breaks down into cyanide oxide, phosgenes and nitrogens that are extremely dangerous" according to a 2017 study. This is how HK police uses Hongkongers for human experiments: https://www.hongkongfp.com/2019/08/09/hong-kong-reporters-coughed-blood-developed-rashes-tear-gas-exposure-doctors-say/ https://www.hongkongfp.com/2019/08/09/hong-kong-reporters-co...