If you’re planning to climb Denali, North America’s tallest mountain, you may have to pack up your poop: Denali National Park in Alaska may soon require climbers along the West Buttress route to carry all of their poop in a bucket instead of dumping it into a glacier. While it might not sound fun to carry an extra 1.8 gallons (about 7 liters) of feces in your backpack, the measure will keep the mountain clean and safe for visitors.

The change in poop regulations comes after research has shown that feces dumped inside crevasses don’t disintegrate, as it was originally thought. Instead, the poop is expected to resurface downstream within decades. And nobody wants to see poop stains on a pristine mountain landscape. “The average climber that comes to Denali is focused on a one-time trip,” says Tucker Chenoweth, a mountaineering ranger at Denali.

Packing up poop isn’t that unusual. At the Grand Canyon, if public restrooms aren’t available, visitors are required to bury their poop in “catholes” that are six inches (15 centimeters) deep and 200 feet (61 meters) away from water, trails, and campsites. Yosemite asks cliff climbers to pack up their feces in “poop tubes,” to be emptied in pit toilets when the climb is over. The park also gives great tips for making your own tube and pleads that the poop tubes not be thrown off the cliffs. (“The summits of popular big walls in Yosemite are often littered with stinking tubes.”)

Denali has had a poop problem for years. Since 1970, over 34,000 climbers have left behind an estimated 66 metric tons of feces along the West Buttress climbing route, the most popular way to reach the summit. Visitors were complaining of how dirty the camp at 17,200 feet (5,243 meters) was, according to Chenoweth. “It was like a cat box up there,” he tells The Verge.

All that human waste is dangerous because climbers on Denali get all of their drinking water from melting snow. If the snow is contaminated with poop, then anyone who drinks it is at risk of stomach problems and diarrhea. A 2002 survey of 132 climbers showed that 29 percent had intestinal infections, called acute gastroenteritis, within one to 21 days after arriving at Denali. When you’re that up high a mountain, getting that sick is life-threatening.

But installing public toilets isn’t practical, Chenoweth says. Rangers would have to fly helicopters over 50 miles (80 kilometers) to empty the latrines. And so, in 2007, the National Park Service began requiring climbers to collect their poop into biodegradable bags and store them inside a large, green bucket called the Clean Mountain Can. This plastic bucket weighs 2.2 pounds (1 kilogram) and can hold 1.8 gallons (about 7 liters) of poop — or around 10 to 14 dumps, according to the NPS. Right now, climbers below 15,000 feet (4,572 meters) are allowed to empty those cans and toss the biodegradable bags down deep crevasses in the Kahiltna glacier. There, rangers thought, the poop would be broken down or exposed to such extreme temperatures that the bacteria couldn’t survive.

But poop samples collected from the mountain show that “frozen solid and wind-desiccated” feces still contain dangerous bacteria like E. coli, according to a 2012 study. Low levels of E. coli were also found in the Kahiltna River, which flows from the Kahiltna glacier. Though the river isn’t used as a drinking water source, it is used for recreation, Chenoweth says.

The poop dumping rules also create other problems: climbers throw the biodegradable bags into undesignated crevasses, which are too shallow. So birds like ravens pick at the bags, get smeared in poop, and then carry the contamination wherever they fly. Visitors also put plastic wrappers and wet wipes, which are not biodegradable, into the bags, thus littering, Chenoweth says.

Enough is enough! Based on the recent research, the National Park Service has decided to update its poop regulations: no more emptying the Clean Mountain Cans into crevasses. Instead, climbers have to collect all of their poop in the cans and then deposit them in a designated fenced-in area at the ranger station at Talkeetna. Here, the cans are collected by a local contractor that sanitizes the cans and returns them to the park. (Climbers at Camp Four, a campsite at 14,200 feet (4,330 meters), will still be able to toss their poop down one particular crevasse, according to The Associated Press.)

Of course, there’s no way for the rangers to really police what people do after going to the loo. But Chenoweth hopes that, once the regulations are approved, hopefully before the climbing season starts in May, visitors will be more conscious about their number 2 — and keep an eye on each other. “They’re going to know it’s not okay” to throw stuff down crevasses, he says.

At the end of the day, if the mountain is clean, everyone will benefit. “We feel like we’re on to something really neat here,” Chenoweth says.