Peak poop: climbers of tallest mountain in US told to take their feces home

Mountaineers at Denali in Alaska put human waste in a glacier but research finds it can persist, staining ice and polluting water sources

Climbers who come from around the world to tackle North America's tallest mountain face packing out more of their own human waste after an expert found that a glacier in which much of it is dumped is probably not breaking it down.

National Park Service (NPS) rangers trying to protect the spectacular slopes of Denali - formerly widely known as Mount McKinley - in Alaska are concerned that human poop is blighting the environment there.