Subpart D defines each hazard class and the tests and criteria for assignment: Class 1 explosives and their divisions and compatibility groups with the EX approval process (173.50 to 173.62), Class 2 gases (flammable, non-flammable, poisonous, 173.115), Class 3 flammable and combustible liquids by flash point and boiling point (173.120), Class 4 flammable solids, spontaneously combustible and dangerous when wet materials (173.124), Class 5 oxidisers and organic peroxides (173.127, 173.128), Class 6 poisonous materials by oral, dermal and inhalation toxicity and infectious substances (173.132 to 173.134), Class 7 radioactive material (173.403 and the activity-based definitions), Class 8 corrosives by skin corrosion and steel and aluminium corrosion rates (173.136), Class 9 miscellaneous including lithium batteries (173.185) and elevated temperature materials, and ORM-D. Section 173.2a sets the precedence of hazards for materials meeting more than one class, and 173.21 lists forbidden materials and packages. Packing groups are assigned per class under 173.121, 173.125, 173.129, 173.133 and 173.137.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.