So, if you're a retailer, contact the manufacturer about the certification, if you're the e-liquid manufacturer contact the bottle manufacturer for the certification. Not a bad idea for all three of those to have evidence of compliance, I'm guessing.
When a Cert is Issued on something like CRP, everyone in the Supply Chain usually holds the Cert.
But the Retailer is Almost Always the one who Bears the Responsibility to Ensure that Compliance is Meet. Because they are the Ones who are Selling to the End User. And the End User are the Ones that the Requirement was/is supposed to Protect.
A Retailer doesn't have to Know Everything about CRP. Or what Mechanics are involved with Cert-ing a CRP Container. Doesn't have to Know much in fact. Only what Standard the CRP needs to Adhere to. And that I have a Piece of Paper (a Cert) that Legally States that the Containers Meets these Standards.
This is Also where Retailers get into Trouble.
Because as the Manufacture of a Container, I can Call just about Anything CRP. But if it Hasn't been Certified by an Independent Testing Company who is Legally Allowed to Issue a given Cert, the container I sell and the Container the Retailer buys Isn't going to Comply with the PPA.