NEW YORK -- Foam cups at Dunkin' Donuts will soon be history, removing what the company estimates will be a billion of them each year from the waste stream. Dunkin' said Wednesday that the polystyrene foam cups will be completely phased out from its stores globally by 2020. Because foam packaging decomposes slowly, ends up in oceans and can harm marine life and other animals that ingest it, there has been push to ban its use. Dunkin' Brands Group, Inc., based in Canton, Massachusetts, joins other chain restaurants trying to diminish its footprint. McDonald's said last month that it would use only recycled or other environmentally friendly materials for its soda cups, Happy Meal boxes and other packaging by 2025.