# Our CBAM-listed steel part has rubber or plastic fitted. What mass and emissions are declared?

Canonical: https://senseible.earth/answers/cbam-steel-part-with-rubber-or-plastic

For the 50-tonne threshold, the net mass declared under the CN code counts, rubber or plastic included. On actual values, the embedded emissions are only those of the metal part, treated as a precursor, because the other material is not a CBAM good. That is the EU's CBAM Q&A 4.30.

## When this applies

Only once customs classifies the assembled part under a CN code listed in Annex I of the CBAM Regulation. Whether a part goes under a steel, rubber or plastic code is a customs decision. If it lands under a non-listed code, CBAM does not apply to it.

## Two masses, two uses

- Threshold: the whole net mass on the customs declaration for that CN code.
- Embedded emissions on actual values: the metal part as a precursor, using its supplier's verified figure or the EU default value. The rubber or plastic adds nothing.
- On default values: the default value for the declared CN code in Annex I of Implementing Regulation (EU) 2025/2621, applied to the declared mass.

## Records to keep

- Bill of materials with the metal mass per piece.
- Purchase invoices for the steel or aluminium, by supplier.
- Each supplier's verified figure, if you have one.

## Example: 20 t of steel brackets with rubber pads, one year

- Net mass declared under the steel CN code: 20 t, all counted toward the threshold
- Steel in the shipment: 18 t; rubber: 2 t
- Embedded emissions of the steel parts: 18 t x 2.10 t CO2e per tonne = 37.8 t CO2e
- Per tonne of declared goods: 37.8 / 20 = 1.89 t CO2e

Example figures. 2.10 t CO2e per tonne stands in for the steel supplier's verified figure.

## What Senseible does here

Senseible's CBAM Suite carries bought steel and aluminium by supplier and CN code into your figure, from your purchase invoices. We build it from your records, check every figure in-house, and an accredited verifier we partner with signs it off. Have your own verifier? Send it to them.

- [Build your CBAM figure](https://senseible.earth/cbam-suite)
- [How the 50-tonne threshold is counted](https://senseible.earth/answers/cbam-50-tonne-threshold-how-counted)
- [Precursor with no verification report](https://senseible.earth/answers/cbam-precursor-supplier-no-verification-report-defaults)

Sources: [European Commission, CBAM Questions and Answers (15 October 2026), question 4.30](https://taxation-customs.ec.europa.eu/document/download/013fa763-5dce-4726-a204-69fec04d5ce2_en?filename=CBAM_Questions%20and%20Answers.pdf), [Implementing Regulation (EU) 2025/2621, default values](https://eur-lex.europa.eu/eli/reg_impl/2025/2621/oj/eng)

Last reviewed 2026-11-01.