The DOT Hazard Codes 1 Explosive 2.1 Flammable gas 2.2 Non-flammable gas 2.3 Poisonous gas 3 Flammable liquid 4.1 Flammable solid 4.2 Spontaneously combustible 4.3 Dangerous when wet 5.1 Oxidizer 5.2 Organic peroxide 6.1 Poison - keep away from food 6.2 Infectious material 7 Radioactive 8 Corrosive 9 Miscellaneous