2. To which class should a dangerous good that meets the criteria for membership of several classes be assigned?

Each dangerous good is assigned to one class and one class only, with the possibility of "subsidiary" hazards.

Goods presenting several hazards must therefore be assigned as a priority to the class corresponding to the predominant hazard, in the following order of importance (§ 2.1.3.5.3 of the ADR):

• 1. Class 7 materials (except for radioactive materials in excepted packages) ;

• 2. class 1 materials ;

• 3. class 2 materials ;

• 4. class 3 liquid desensitized explosives;

• 5. self-reactive substances and solid desensitized explosives of class 4.1 ;

• 6. pyrophoric substances of class 4.2 ;

• 7. class 5.2 materials ;

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