The script corrects the defect of the game developers. Now tear gas grenades also deal damage to our Main Hero, similarly to other peds, CJ will cough and choke.
Therefore, now you should use this weapon more carefully. If the grenade is right under your feet, you have a few seconds left to run back to a safe distance.
The script does not cause problems in SA-MP, since this defect has already been fixed there, the script simply will not start if you go into multiplayer.