The National Park service is studying the impact of the long term depositing of feces on the Kahiltna Glacier. Since 2006 (optionally at 2000) Denali had been using “Clean Mountain Cans,” which serve as ultra-portable, snap-shut toilets, strapped to climbers’ packs and toted around the mountain. Climbers had been permitted to dump the contents of the can into crevasses at the 7,000-foot and 15,000-foot levels.