Most emissions come from burning something. Process emissions do not — they come from a chemical reaction, and they would occur even if the reaction were driven by an entirely clean energy source.
The clearest example is cement. Making clinker requires heating limestone until it decomposes into lime and carbon dioxide. That CO₂ is released by the chemistry, not by the fuel, and in cement production it frequently exceeds the emissions from the fuel used to reach the temperature.
Industries that should check
Cement and lime
Calcination. Usually the largest single source in the inventory.
Glass and ceramics
Carbonate decomposition during melting and firing.
Chemicals and fertiliser
Ammonia production and a range of other reactions release CO₂ directly.
Iron, steel and aluminium
Reduction processes, and carbon consumed as a reagent rather than a fuel.
Food and beverage
Fermentation, and CO₂ used in carbonation where it is not recovered.
The tell
If your disclosure's Scope 1 consists entirely of fuel lines and your process chemically releases CO₂, something is missing. This is the first thing a sector-literate reviewer checks, and it is one of the few omissions that is obvious from the outside.
How it is measured
Not from fuel. Process emissions are calculated from production volumes and the chemistry: quantity of raw material consumed, multiplied by a factor derived from the stoichiometry of the reaction, with adjustments for material composition and for any CO₂ recovered rather than released.
The IPCC national inventory guidelines set out the methodology for the main industrial processes, and it is the standard reference for corporate inventories too. It also means you need production and raw material data in the same system as your energy data — which is the same requirement CBAM imposes on exporters of covered goods, so the work serves twice.