There are several similar and overlapping efforts to define and conceptualize a closed loop lifecycle of product and materials management, with many of these efforts being spearheaded by government agencies, entrepreneurs, scientists and non-governmental organizations. While similar to SMM, these product lifecycle models focus largely on the end-of-life management of materials while SMM focuses on the impacts materials, products and services have on the environment such as eutrophication, acidification, ozone layer depletion, global warming and aquatic toxicity as well as energy and water use. The Product Stewardship Institute defines Product stewardship as: "the act of minimizing the health, safety, environmental, and social impacts of a product and its packaging throughout all lifecycle stages, while also maximizing economic benefits. The manufacturer, or producer, of the product has the greatest ability to minimize adverse impacts, but other stakeholders, such as suppliers, retailers, and consumers, also play a role. Stewardship can be either voluntary or required by law".British Columbia (BC) has an extensive product stewardship network administered by BC Recycles and composed of BC producers and brand owners who are required by law to collect and divert end-of-life products and packaging. The U.Ks Waste and Resource Action Programme (WRAP) defines the Circular Economy as being an alternative to the traditional take, make, waste economy to one that keeps resources in use as long as possible, extracts the maximum value from the materials while they are in use, then recovers the materials to generate new products at the end of the service life. The Ellen MacArthur Foundation works to accelerate the transition to a circular economy by working with businesses, academia and governments throughout the world to develop an economy that is restorative and regenerative by design and seeks to keep products, components and materials at their highest use and value at all times, distinguishing between biological and technical cycles. The Dictionary of Sustainable Management defines Cradle-to-Cradle as "A phrase invented by Walter R. Stahel in the 1970s and popularized by William McDonough and Michael Braungart in their 2002 book of the same name. This framework seeks to create production techniques that are not just efficient but are essentially waste free. In cradle-to-cradle production, all material inputs and outputs are seen either as technical or biological nutrients. Technical nutrients can be recycled or reused with no loss of quality and biological nutrients composted or consumed. By contrast cradle-to-grave refers to a company taking responsibility for the disposal of goods it has produced, but not necessarily putting products’ constituent components back into service."