Hi Jdc,
At one point they were using materials imported from China but as you can see in post #513 here and in their own reply in post #8 here things have changed and they now use foams that are made in the US and are CertiPur certified and I have also included them in the list of some of the better memory foam options in post #12 here.
I’ve added links to the more up to date information in the post you read so that others who read it will also realize it’s not current any longer.
Phoenix