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Why Are There Harmful Chemicals on Mount Everest?

The glory of climbing Mount Everest may last a lifetime, but the chemicals left behind will remain forever. The downstream effects will impact humans and the environment for centuries.

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There are few pristine places left in the world and, according to a new study, Mount Everest isn’t one of them. In 2021, landmark research showed accumulation of “forever chemicals” at the Third Pole for the first time. In addition to human refuse, used oxygen bottles, and plastic waste, we now know that climbers are also leaving behind cancer-causing compounds.

Unfortunately, it looks like the gear climbers use to get to the top of the mountain is the main source of chemical pollution. Poly- and perfluoroalkyl substances (PFAS) are a group of manmade materials that are pervasive in consumer and industrial products. They are termed “forever” because they don’t degrade easily in nature or the human body. In technical products, PFAS are what make things waterproof. Across the Everest base camps and climbing routes, tons of discarded equipment can be found. The PFAS-laden gear—old tents, fixed ropes, food packaging, etc.—is the likely source of chemical leaching, according to the paper. 

Dr. Kimberley Rain Miner is an adventure-minded scientist and lead author of the study published in Science of the Total Environment in March of this year. The former Wilderness Firefighter has studied banned and legacy chemicals, such as polychlorinated biphenyls (PCB) and di-chloro-diphenyltri-chloroethane (DDT), on glaciers and mountain ranges around the world. Miner concluded that chemical contamination found at these remote locations was likely deposited atmospherically, from snow, rain, and wind, and offers a baseline expectation for pollution levels found in other mountainous areas.

“The difference was that most of the glaciers that I had sampled to date had minimal human climbing,” she says. 

On Everest, the researcher’s glacial melt and snow samples showed a much higher concentration of PFAS than expected. The numbers were greatest at the areas where climbers spend the most time: Base Camp I and II. Samples taken from a fresh snowdrop by Cyclone Fani did not show significant PFAS levels.

“It is sad to think that beautiful, supposedly pristine places high in the mountains were contaminated with toxic PFAS chemicals,” says Dr. Arlene Blum, the Executive Director of the Green Science Policy Institute and pioneering mountaineer who led the first American and all-women’s ascent of Annapurna I.


PFAS chemicals are found everywhere. The U.S. EPA has identified over 6,300 of them, and the synthetics are estimated to be detectable in the blood of 98% of the U.S. population according to a 2007 study by the US Centers for Disease Control and Prevention. The compounds can last for decades or even centuries outside of a laboratory setting. Carbon–fluorine bonds are one of the strongest in organic chemistry.

On the one hand, PFAS provide benefits for outdoor gear such as water repellency, stain and temperature resistance, and friction reduction. On the other, they are highly persistent, accumulate in the bodies of animals and humans, and once there cause a range of issues from cancer to liver toxicity and damage to the immune and endocrine systems. When you’re waxing your skis, surfing in your board shorts, and camping out under the stars you are potentially exposed to PFAS. 

The chemicals are pervasive in the everyday environment as well. They were first developed in the 1940s and quickly made their way into the home as non-stick pans (Teflon) and stain resistance for carpets (Scotchgard™). “When you buy a carpet or a couch, it used to be they’d ask if you want to have the stain repellant treatment. If they said to a mom, ‘Of course the chemicals in that treatment are going to end up in your children for decades to come and are related to cancer and many other health problems,’ she probably wouldn’t choose the treatment. But nobody tells her that,” says Blum. Today, PFAS are found in fast food packaging, apparel, furnishings, fabric softeners, personal care products and more. 

People are most likely exposed by consuming PFAS-contaminated water or food. This is what happened in Parkersburg, W.V., when around 70,000 people were affected by Teflon-polluted drinking water from a DuPont chemical plant. The case became the basis for the movie Dark Waters. There is limited research about whether PFAS can be absorbed directly through the skin at harmful levels, though it can be transmitted by hand-to-mouth transfer from surfaces treated with the substances.

On Everest, discarded gear is exposed to extreme conditions causing leaching and degradation of PFAS onto the Khumbu Icefall and Glacier. The meltwater eventually runs down the Dugla and Lower Pheriche streams which serves water for up to 6,000 people who reside in the Khumbu Valley. And there is a lot of trash. In 2019, the Nepalese Army cleared 10,000 kg of waste (or about 11 tons) from the mountain, but it was hardly a dent. For comparison, in 1963, the American expedition had 900 porters that carried in over 25 tons of supplies. Much of that stayed up there, which is the case for many expeditions. 

Garments shed from daily use too. A recent study from the Netherlands showed that DWR-treated rain jackets will release PFAS in concentrations of 5- to more than 100-fold after being subjected to outdoor weather conditions such as UV radiation, humidity, and high temperature for 300 hours, which mimics the lifespan of outdoor clothing. The study suggests that the chemicals used to make the apparel water-repellent break down over time. 

“PFAS are one of the most heinous chemical compounds in my opinion,” says Kirk Richardson, the Senior Director of Supply Chain Sustainability at KEEN Footwear. 

Since 2020, KEEN eliminated all use of perfluorinated chemicals (PFCs), the term the outdoor industry commonly uses for PFAS. In their research, the company found over 100 different shoe components where chemicals were applied by component suppliers without KEEN’s asking. “You will find them in the most unexpected areas,” says Richardson. “We don’t want or need an anti-wick, and we don’t need anti-stain surfactants applied everywhere.” The detoxification process took seven years and cost in excess of a million dollars.

PFAS are one of six classes of chemicals that the Green Science Policy Institute (GSP) says can be commonly found in outdoor gear. GSP, where Blum is the Executive Director, argues that because of the chemicals potential for harm, they should only be used when necessary. Other classes include antimicrobials, flame retardants, and phthalates. Without PFAS, KEEN has eliminated five of the six classes from their products. 

KEEN is a mid-size firm, yet billion dollar leaders such as Patagonia and VF Corporation (which owns The North Face) haven’t banned PFCs whole cloth. Both iconic outdoor companies are headed in the right direction, but they lag behind smaller businesses like Páramo and Nau which have designed their entire product line to avoid such compounds. Other companies like Columbia, Deuter, and Mammut have introduced PFC-free gear as well. Still, when the dangers of PFAS chemicals have been known for decades, why are outdoor brands still using materials that harm humans, animals, and the environment? They may be forced to change soon.

California has unveiled sweeping chemical-control policy that will set a precedent in the industry. The State’s Department of Toxic Substances Control wants to regulate PFAS as a class in certain consumer products. The argument is that persistence may be “the most important single criterion affecting chemical exposure and risk via the environment.”

The state’s commentary on the regulation says, “In the case of PFAS, we believe that all members of the class have a potential for significant and widespread adverse impacts.” The policy will not necessarily lead to regulation, though countries like Denmark and states such as Washington and New York provide examples where lawmakers banned PFAS as a class narrowly, from paper and cardboard food packaging. 

Consumers can do their part as well. “If things are stain or water repellant, you want to ask if they contain PFAS or PFCs, and not to buy those products,” says Blum. “You are making a decision to buy something with chemicals that will contaminate our planet forever.” In other words, think long and hard about purchasing that non-stick camping pot, antimicrobial underwear, or waterproof jacket. And for forever’s sake, remember to pack-out what you pack-in.