What should be filled in the field "steel mill identification number" in the CBAM report?
The "steel mill identification number", also known as "heat number", in principle indicates the mill/furnace where the steel product came from. In case there are many different heat numbers, we suggest leaving a comment. However if there are only a few heat numbers, they can all be filled in the field.
Note that, while we encourage you to provide this information, the "steel mill identification number" is an optional field.
Source: EC’s Questions and Answers on CBAM