For example, the risk nature of installing risky articles can be divided into ten categories: explosive articles, oxidizers, compressed gases and liquefied gases, self-igniting articles, incinerated articles in water, flammable liquids, flammable solids, poisonous articles, corrosive articles and radioactive articles. Every item must be marked when it is packaged. Specific characteristics. Some can not be directly packed in cartons, such as potassium dichromate, sodium dichromate and sodium alum, which are red crystals and toxic. Before being put into cartons, they should be placed in consolidated iron barrels. The thickness of iron plates should not be less than 1.2 mm, and the barrel mouth should be strictly sealed.