The reappearing poop wasn’t only disgusting, it also posed a health hazard. Human feces contain pathogens (see What’s in Poop?). These disease-causing microscopic agents, such as bacteria and viruses, contaminated the surrounding snow—the same snow that climbers melted for drinking water. As a result, many of them got sick.
Dismayed by how dirty the camps were, Robinson began developing a portable toilet. It would allow climbers to carry their waste off Denali. The Clean Mountain Can (CMC) is a small, lightweight container that can be strapped to a climber’s pack. Each one is lined with a biodegradable bag that will break down in the environment.
In 2007, the National Park Service began requiring all climbers to use CMCs at Denali’s highest and lowest camps. In between, they could empty the cans by throwing the bags into crevasses. The camps became much cleaner. But Robinson wondered: What would become of the tossed waste? He asked Michael Loso, a glaciologist at Wrangell-St. Elias National Park & Preserve in Alaska, to find out.