Sometimes this question again comes up. Mostly from seafarers and port operators. Some consider that class 1 explosives are the most dangerous and class 9 miscellaneous dangerous substances and articles the least.

Some seafarers consider class 9 the most dangerous as it is considered harmless hence less care is being given to it in the transport operations.

Is the numerical order of the classes of dangerous goods listed as per order or danger?

Answer is no!

“The numerical order of the classes and divisions is not that of the degree of danger.”

[IMDG Code and Model Regulations, 2.0.1.1]

However, among the gases of class 2.1, class 2.2 and class 2.3, class 2.3 takes precedence over class 2.1 and class 2.2 and class 2.1 takes precedence over class 2.2.

[IMDG Code 2.2.2.4, Model Regulations 2.2.2.2]