Larry, while is typically considered metal where you would expect them to be found in metal products, they can be found in other non-metal products (think lead paint). I think that label pertains to the plastic wrapping as DEHP is "plastic softener". It would probably be a good thing for Stanbroil to clarify whether it is the shipping material or the product that the warning is designed for.
"Lead may also be found on older toys made in the U.S. before the ban. The use of
lead in plastics has not been banned.
Lead softens the
plastic and makes it more flexible so that it can go back to its original shape. It may also be used in
plastic toys to stabilize molecules from heat."
Same for Chromium:
"Industrial uses of hexavalent chromium compounds include chromate pigments in dyes, paints, inks, and
plastics; chromates added as anticorrosive agents to paints, primers, and other surface coatings; and
chromic acid electroplated onto metal parts to provide a decorative or protective coating."