These 9 hazard classes have been established
internationally by a United Nations (UN) committee to
ensure that all modes of transport (road, rail, airand sea)
classify dangerous goods in the same way (Table 1).
Consequently, in the UN Model Regulations each
substance has a name (called a Proper Shipping Name)
and a four digit UN number and, according to its chemical
and physical characteristics, is assigned to a class and a
packing group. It should be noted that the numerical order
of the classes does not indicate the degree of danger