Guidance

Verifying emissions data for Carbon Border Adjustment Mechanism (CBAM) goods

Find out what you must do if you’re verifying emissions data for the Carbon Border Adjustment Mechanism (CBAM).

• From: HM Revenue & Customs
• Published: 16 October 2026

If liable persons (the importers) choose to use actual emissions data on their Carbon Border Adjustment Mechanism (CBAM) tax return, the installation producing the CBAM good that was imported must have: 

• monitored this emissions data over one calendar year (1 January to 31 December)
• made sure that this data has been verified

To verify emissions data for CBAM you will need to both: 

• carry out the activities that verifiers must do when verifying emissions data — read the CBAM technical guidance
• meet the eligibility requirements to verify for CBAM 

 Eligibility requirements to verify for CBAM

You must be accredited by an eligible accreditation body against the:

• requirements for CBAM verifiers set out in legislation 
• following international verification standards set out by the International Organisation for Standardisations (ISO): 
  • ISO/IEC 17029 (Conformity assessment - General principles and requirements for validation and verification bodies), on the ISO website 
  • ISO 14065 (General principles and requirements for bodies validating and verifying environmental information), on the ISO website

To verify a particular installation’s emissions data, you must:

• make sure the scope of your accreditation covers the installation’s production processes
• be independent of that installation

Getting accredited to verify emissions data

You must apply for accreditation for CBAM from an eligible accreditation body.

 Verifying the emissions data

You must make sure that you carry out certain activities when verifying an installation’s emissions for CBAM. Read more about these in the CBAM technical guidance. 

Once you’ve verified the installation’s emissions data for the calendar year (1 January to 31 December), you must create a verification report and issue the report to the installation operator. The verification report must include your verification opinion statement on whether the data have been verified as satisfactory. The report may include verification summaries for each CBAM good produced at the installation.

Read about what the verification report needs to include in the CBAM technical guidance.

After you’ve verified the emissions data

The installation operator will give either the full verification report or a good-specific verification summary to the importer who imported the CBAM good it produced.

The importer will:

• report actual emissions to HMRC on their CBAM tax return
• keep hold of the verification report or verification summary as evidence