Is a supplier declaration sufficient evidence for a green claim?

A supplier declaration is self-disclosure and does not meet the requirements for a certification scheme. It can form part of internal documentation, but it does not shift liability. Responsibility for an environmental claim towards consumers stays with whoever makes the claim.

What does carry the claim is evidence from a certification system: independent testing, conformity assessment by a third party and publicly available terms. At flustix, laboratories accredited to ISO/IEC 17025 do the testing, certification follows ISO/IEC 17065, and every certificate can be looked up by its licence number in the public database.