What are the challenges facing the textile industries companies like H&M as they attempt to design sustainable cleaner products?

What protocols, procedures and processes across H&M$$s supply chain are required to make sure that electronics products are designed to meet environmental product goals? How can H&M govern such the protocols, procured and processes effectively?

Would it work if a manufacturer sends a list of banned substances its suppliers? What else does the manufacturer need to do to ensure that no banned substances are being used in producing the components for the products?