Column 6, Label Codes, specifies the hazard warning labels
that must be applied to each package filled with a material
conforming to the associated hazard class and proper shipping
name, unless the package is otherwise excepted from labeling.
If two label codes are listed, the first represents the primary
hazard and the second represents the subsidiary hazard. No
label is required for a material classified as a combustible liquid
or for a Class 3 material that is reclassified as a combustible
liquid. The codes contained in Column 6 are defined
according to the Label Substitution Table found in
§172.101(g). Additional labeling requirements are found in
§172.402.
