incendiaries are chemical weapons because their main mechanism is fire rather than explosives or ballistics, though thermobarics do blur the line a little. i thinj in the us, flamethrowers were once classified as "chemical shears" due to their use in clearcutting vegetation. in general they are meant to burn contaminated material. it's pretty metal though, the cbrn corps wielding cleansing flame to purge toxic and diseased material.
Singapore