>>2093979
>chemical
Could leave long lasting negative impacts on the environment, you especially don't want that shit in the drinking water or soil intended for farming.
>biological
While some of these factions do have certain groups of people they want dead/gone I still don't think they'd risk using biological weapons with the potential of spiraling out of control and also harming the environment or groups of people they didn't intend to use bio weapons on.

https://www.youtube.com/watch?v=ATc1CiY1Bck&ab_channel=Slimelord8277