Legally sound certification:
Free Claim CheckEmpCo: environmental claims and labels
Responsibility sits with the company making the claim. In practice the testing is organised through the certification programme, in this order.
Depending on programme and product this takes four to twelve weeks.
You can, and the result is a test report on the sample submitted. For internal documentation that may be enough. As soon as it becomes a claim towards customers or consumers, three things are missing: assessment against a published programme, ongoing monitoring, and verifiability by third parties. The full route is set out on the page about the certification process.
Sources: ISO/IEC 17065 (requirements for certification bodies)
Editorial responsibility: Malte Biss, CEO & Founder of flustix