I think sarin gas may be a chemical weapon.
Sarin is a nerve agent, human nerve agents are pretty darn close to bug sprays, its basically spray, for humans.
It’s kind of word salad, “Chemical biological”, but if we’re looking for a descriptor base, Chemical would be from construction of physiologically active substances from basic chemicals, Biological would be organism oriented, and “Chemical Biological” would be a toxin chemical derived from extraction or growth from a living organism. Think Ricin, Tetanus or Botulinum, or tetrodotoxin...