Carbon monoxide co Cas no.: 630-08-0 Einecs no.: 211-128-3 Un no.: un1016 Purity: 99.9%-99.99% Dot class: 2.1 & 2.3 Appearance: colorless Grade standard: food grade, industrial grade, medical grade Chemical industry: Carbon monoxide is an industrial gas that has many applications in bulk chemicals manufacturing. Mainly be used as reducing agent. Laser: Carbon monoxide has also been used as a lasing medium in high-powered infrared lasers.