Hi Shirley,
These kinds of “absolute” statements are rarely based on fact and are usually just an opinion that has been poorly researched and repeated often enough that they take on the appearance of being factual when they’re not. As often as not … they are more about marketing than anything else (ie: buy my mattress and not “that” mattress). There are good quality foams being manufactured in China and poor quality foams as well. If a foam pourer is pouring and testing their product to the same standards as a foam poured in the US then there would be little reason to differentiate between them except perhaps for reasons that had nothing to do with the quality or safety of the foam such as a personal preference to buy American. The Classic Brands manufacturing facility in China manufactures to the same standards as US facilities and are CertiPur certified so I would put them on a level playing field and compare their foam quality based on density. They meet the guidelines I use for memory foam in post #10 here although if someone wants to exclude them because of their country of origin then that would be a personal decision that they of course could make for reasons other than the quality or relative safety of the foam. From a safety point of view I would have no issue with any of the foam they use in their mattresses although of course even CertiPur is not a guarantee some people who are very sensitive or who suffer from MCS (multiple chemical sensitivity) for example won’t have issues with memory foam or polyfoam (or other materials that most people wouldn’t be sensitive to) no matter where it’s made but they are outside the norm.
CertiPur isn’t perfect but it’s certainly a step in the right direction.
There are a few memory foams that are certified by Oeko-Tex which is a stricter standard than CertiPur (such as Spaldin mattresses) but these are mostly made in Europe. There are also a few foams that are certified by GreenGuard (such as Tempflow mattresses) but CertiPur is by far the most common certification standard in North America for polyfoam and memory foam.
Phoenix