Some foreign suppliers are going to be utterly unaware of your local legislation. In fact, I'm pretty sure some of them will sign any statement you send them, just to finish dealing with their mailbox.
I would insist that the supplier in question be GFSI certified and also ask for:
1) a product specification that lists all the properties of the packaging (size, color, weight, material, etc)
2) analytical reports for migration
3) a statement that the packaging conforms to the legislation of all the countries were you plan to use and sell the packaging.
If you run into trouble obtaining these documents, it's probably not the right supplier to use.