Do you know where the cotton in your T-shirt was grown or how much pollution was generated by its production? If that T-shirt was made by Patagonia, you could easily find out.

Supply chains are, for the most part, opaque. But a handful of companies, such as Patagonia, are working to make their supply chains more transparent—boldly letting their customers, activists and competitors see their strengths and their weaknesses. The Ventura, California-based firm has created a path-breaking website called The Footprint Chronicles that invites consumers to track the impact of specific Patagonia products from design through delivery