Colorado Revised Statutes Title 9. Safety Industrial and Commercial § 9-6-102. Packing for shipment

It is unlawful to ship, send, or forward nitroglycerine, glycerine oil, nitrated oil, nitroleum or blasting oil, or to transport any of the same upon any vehicle of any description, or to deliver the same to be transported, carried, or conveyed unless the same is securely enclosed, deposited, or packed in a metallic vessel surrounded by plaster of paris or other material that is nonexplosive when saturated with such oil or substance, and separate from all other substances, and the outside of the package containing the same is marked or labeled in a conspicuous manner with the words “nitroglycerine--dangerous”.