What emission factor should I use for the steel I buy in my Scope 3?

Ask the mill first: a product footprint, EPD or verified CBAM figure for the grade you buy is the best factor. Without one, use a published average for the mill's production route, not one global figure. Spend-based factors are the last resort, labelled as rough.

The order to try

1. Mill-specific data for the product: an EPD, a product carbon footprint, or embedded emissions the mill reports for CBAM.
2. The mill's own plant intensity, if it publishes one, adjusted for the product form you buy.
3. A route average: blast furnace, coal DRI, gas DRI or scrap electric arc furnace, from worldsteel or a Ministry of Steel publication, with its year.
4. A spend-based factor per rupee, only when you have no quantity.

Know the route and the product form

Route changes the factor more than anything else. Scrap-based electric arc furnace steel sits well below blast furnace steel, and coal-based DRI, common in India, can be higher than blast furnace. Ask your supplier or trader which mill and route the steel came from.

Product form adds to it. Crude steel averages stop before rolling. Hot-rolled coil, cold-rolled sheet, galvanised sheet and bright bars carry extra energy for each step, so check that the factor's boundary matches what you buy.

Count what you buy, not what ends up in the product

Scope 3 Category 1 covers the tonnes purchased in the year. Offcuts and scrap you sell are part of that purchase; their onward recycling is a separate question. Use the weight on the invoice, not the finished part weight.

Using CBAM defaults with care

EU CBAM default values, set in Implementing Regulation (EU) 2025/2621, add a mark-up on top of the underlying country figure, so they run high on purpose. Treat them as a conservative upper figure, not an average, and label them that way if you use them.

Worked example: 120 t of hot-rolled coil

• Mill EPD for the coil: 2.40 t CO2e per tonne (illustrative value for the arithmetic)
• Scope 3 Category 1: 120 x 2.40 = 288 t CO2e
• If 15 t of offcuts are sold as scrap, Category 1 still uses the 120 t bought

Replace the illustrative value with the mill's published figure and keep the EPD with the invoices.

What Senseible does here

Senseible keeps steel purchase lines in a separate supplier evidence trail with the invoice quantity. Where only spend is available, it provides a spend-based estimate labelled as spend-based with wider uncertainty.

• Emission factor for goods bought via a trader
• Benchmarking a steel supplier's intensity
• Scope 3 for steel in India

Sources: GHG Protocol Scope 3 Standard (2011), Ch. 7 data collection and quality, worldsteel Sustainability Indicators report (latest edition), Implementing Regulation (EU) 2025/2621 (CBAM default values)

Last reviewed 2026-10-18. Route averages differ by year and edition; cite the edition you use and check Ministry of Steel and worldsteel updates.