Snow of Tomorrow | Fluorine-free future on the slopes

Since the first successful syntheses of fluorinated chemicals (PFAS) at the end of the 19th century and the subsequent boom in many areas of application in the 1980s and 1990s, these chemicals have been accumulating in the environment worldwide. Due to their extreme persistence, they are only broken down very slowly. Almost everyone now carries these non-naturally occurring substances in their blood. PFAS reach even the most remote regions of the world via the earth's circulatory system. The public focus on the PFAS group of substances and on PFOA (perfluorooctanoic acid) in particular arose in the 1990s as a result of revelations about environmental pollution and health risks for employees of the DuPont company, which used PFOA to manufacture Teflon. Despite early indications of toxicity, PFOA continued to be used for decades until extensive legal cases and large-scale health studies in the 2000s and 2010s proved both the harmful effects and the company's responsibility for numerous illnesses and deaths. These events were also documented in film productions.

These PFAS scandals are not a problem far removed from the USA - the consequences of PFAS production can also be felt in Germany and many other European countries. In the district of Altötting in Bavaria, blood donations from local residents are no longer allowed to be used for blood storage - due to the high level of PFOA contamination in the population. This is due to the decades-long discharge of contaminated wastewater from the Gendorf Chemical Park. Headlines like:

"PFAS also discovered on the Matterhorn"
"PFAS in drinking and bottled water worldwide - global contamination confirmed"
"EU minister tests positive for PFAS - despite no chemicals"
"From the Danube to the Arctic: Europe struggles to put a stop to perpetual chemicals"

Despite increasing scientific evidence and growing public concern, there is still no comprehensive, global ban on all PFAS - partly because strong lobbying by chemical and industry associations has repeatedly delayed or weakened stricter regulations. However, this article focuses on a specific area of application - the use of PFAS in ski waxes, their function and the associated health and environmental consequences.

According to current classifications, there are currently over 4700 different PFAS. To understand this group of substances, it is important to differentiate between non-polymeric PFAS and polymeric PFAS. Non-polymeric PFAS are smaller molecules, including well-known substances such as PFOA and PFOS (perfluorooctane sulfonic acid). Polymeric PFAS include large, chain-like molecules such as Teflon (PTFE - polytetrafluoroethylene), but also other fluorinated plastics. In this article, the chemical name PTFE is deliberately used instead of the brand name "Teflon" in order not to unintentionally strengthen the company DuPont (now Chemours), which is associated with numerous health and environmental problems.

The smaller, non-polymeric PFAS such as PFOA or PFOS are particularly problematic. They are water-soluble, mobile, can spread in the environment, accumulate in the body and are therefore considered critical to health. Polymer PFAS, on the other hand, are large molecules, hardly soluble in water and are generally not absorbed by the body - they are considered less risky in direct use. However, the fluorine-containing precursor compounds that are used in the production of PTFE and can enter the environment remain problematic. It is precisely these differences that make uniform regulation of the entire PFAS group very complicated.

The science behind ski waxes - how gliding on snow works

In order to understand why fluorinated waxes are so important in skiing, it is first necessary to clarify how gliding on snow actually works - and what crucial role the wax plays in this.

When skiing or cross-country skiing, friction is created which generates heat. This heat melts the layer of snow under the ski and forms a thin film of water. Depending on the thickness of this film and the properties of the ski wax, this film of water can either improve or reduce the gliding ability of the ski. The thickness of this layer of water depends primarily on how close the temperature is to the melting point. If the temperature falls below -10 °C, the water film disappears almost completely and so-called dry friction occurs: the ski glides directly over the ice crystals in the snow. In these extremely cold conditions, a smooth base and harder waxes are required. They are harder than the snow crystals, reduce mechanical friction, improve gliding and protect the ski surface from abrasion. The closer the temperature gets to the melting point of 0 °C, the thicker the film of water under the ski becomes - an effect known as wet friction. If the film becomes too thick, too much water can even increase friction. In warmer conditions, softer waxes with a higher oil content are therefore required to control the water film and improve glide. Hydrophobic waxes repel water, while targeted profiling of the base draws water away from the sliding surface. In combination, these measures ensure that the ski glides optimally even at higher temperatures.

Waxes containing fluorine are particularly effective as they are both hydrophobic and lipophobic (grease-repellent). They form extremely smooth, chemically stable surfaces that reliably repel water, grease and dirt and significantly reduce wet friction between skis and snow. In addition, they are extremely abrasion-resistant compared to conventional waxes as they bind very strongly to the polymer-based base. Conventional paraffin-based ski waxes usually only have hydrophobic properties, which means that they absorb dirt such as pollen or fine dust, especially on old snow, which significantly minimizes the gel performance. In addition, friction is increased by the rapid abrasion of the ski wax. The main components of fluorinated ski waxes can be divided into three groups.

• Low fluoro (LF) waxes usually contain semi-fluorinated alkanes (SFA) with a fluorine content of around 0.5-1.5 %.

• High fluoro (HF) waxes have significantly higher fluorine contents of 4-12 %. In addition to SFAs, PFCs (perfluorocarboxylic acids) with even-numbered carbon (C) chain lengths (C6 to C14) are also used here.

• Pure fluorine compounds, which were sold under designations such as "Pure Fluorocarbon" (FC) or "Cera F". Perfluoroalkanes (e.g. perfluorododecane) are mainly used here.

Environmental and health risks

PFAS cannot be broken down by the body and accumulate in the organism mainly because they bind strongly to blood proteins. Due to the high stability of the molecules, they remain bound for a long time and can accumulate for years. They can be detected in the blood of practically all people, even newborn babies.

PFOA, formerly used in the production of PTFE, has been particularly well studied because it has been linked to numerous illnesses and deaths worldwide and was therefore the focus of research and regulation at an early stage. Even small amounts can cause organ problems, cancer and birth defects. It has also been linked to liver and thyroid damage, obesity, fertility problems and elevated cholesterol levels. Many other of the thousands of PFAS compounds have hardly been researched, so their health effects remain largely unknown.

The use of PFAS in ski wax is particularly critical, as the health risks here are higher than with many other applications. The waxes are heated during application, which means that the vapors are inhaled directly and the user is exposed to high concentrations of the chemicals. Studies show that professional waxing teams have up to 45 times higher levels of PFOA and 300 times higher levels of PFNA (perfluorononanoic acid) in their blood than the average population.

Ski wax is also a particularly problematic area of application for PFAS from an ecological point of view. A large proportion of the wax is released directly into the environment through abrasion, where it can hardly be biodegraded and therefore continues to spread in ecosystems. The abrasion of ski wax into the environment has already been proven. Above-average PFAS concentrations have been found in ski resorts. On ski race courses, even higher concentrations were measured at the starting point than at the finish.

In the Engadine lakes, up to 2680 nanograms per kilogram of PFOA were detected in the fish grayling and Arctic char, caused by the heavy use of the cross-country ski trails along the lakes. The permissible weekly intake recommended by the EFSA (European Food Safety Authority) is only 4.4 nanograms per kilogram of body weight. Roughly speaking, this means that you should only consume a tiny portion - about a pinch (0.1 gram) of fish per week if the origin and pollutant load are unknown.

How lobbying delays bans

PFAS have been known for decades for their extreme persistence in the environment and the body, as well as their harmful effects on health. The first indications of harmful effects of PFOA on humans and animals date back to the 1980s and 1990s. Despite these findings, regulatory measures were slow in coming. At international level, the Stockholm Convention is the central mechanism for restricting POPs (persistent organic pollutants). The only PFAS that have been included so far are PFOS (perfluorooctanoic acid) in 2009, PFOA in 2020 and PFHxS (perfluorohexanesulfonic acid) in 2022 - each with bans or severe restrictions in the EU, often with transitional periods. REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) also regulates certain PFAS: since 2023, for example, C9-C14 PFCAs have been restricted in production and use. Maximum levels apply across the EU for drinking water and food. Apart from POPs/Stockholm, there is no uniform global PFAS regulation, only national solo efforts.

A particularly visible example is the ski wax industry: Hertel Wax, founded by Terry Hertel, was granted the patent for the first fluorocarbon in 1986. Since then, PFAS have been an important component of many ski and cross-country ski waxes. Following the EU ban on PFOA in 2020, the International Ski Federation FIS (Fédération Internationale de Ski) and the IBU (International Biathlon Union) announced a ban on all PFAS in ski waxes for the 2020/21 winter season. However, according to a press release, the ban initially only applied to PFOA- and C8-based PFAS. In 2023, the ban was finally extended to all fluorinated ski waxes - one of the few bans that covers the entire PFAS group without exceptions. However, this ban is currently limited to competitive sports, which only make up a small proportion of the ski industry, while recreational skiers can continue to use fluorinated ski waxes without restriction.

Alternatives - What's next?

What alternatives are there? Some chemical substitutes such as siloxanes or halogenated kerosenes have comparable gliding properties, but also entail considerable environmental and health risks. In short - everything that works well unfortunately has its disadvantages. So it's back to well-known lubricants such as kerosenes, waxes (e.g. Caranuba wax) or fats, or even metal salts of fatty acids (e.g. zinc stearate). Their properties can also be further improved by targeted additives. New approaches are also exciting, such as bionically inspired surface structures that are based on nature - for example, the structure of fish scales.

There is currently no legal regulation prohibiting the use of ski wax containing fluorine in the leisure sector, and retailers are not obliged to stop selling it either. It is therefore up to every recreational skier to be critical when choosing ski wax. Products containing fluorine should be labeled - if in doubt, it's worth asking!

Most wax brands have been around longer than the current PFAS bans. Therefore, many retailers often still have fluorine-containing residual stocks in their range, even if the respective brand no longer produces and offers fluorine-containing waxes. If you already pay attention to the environmental friendliness of ski wax, you can combine this with regional appreciation and give preference to products from European brands. The most important are:

• HWK Skiwax: Tyrolean ski wax brand that offers fluorine-free waxes, but still has products containing fluorine in its range. Fluorine-free waxes are labeled "FLUOR FREE".

• ZIPPS: German ski wax manufacturer that offers fluorine-free waxes but still has products containing fluorine in its range. Fluorine-free waxes are labeled as "ZeroFluor".

• Holmenkol: German ski wax manufacturer that offers 100% fluorine-free waxes. Funnily enough, PFAS-free wax is available under the name Syntec FF 21 Bar. Actually, "F" is usually the abbreviation for fluorine-containing wax.

• SWIX: Norwegian ski wax brand that now sells 100% fluorine-free wax.

• Red CREEK : Swedish ski wax brand that now sells 100% fluorine-free ski waxes.

• TOKO : Swiss ski wax brand that now sells 100% fluorine-free ski waxes.

• UBERSCHALLWAX: Swiss ski wax brand that has been selling exclusively 100% fluorine-free ski waxes since the beginning (2019)

• FZero : Swiss ski wax brand that now sells 100% fluorine-free ski waxes.

What recreational skiers can do

Ski waxes containing fluorine should no longer be used. Many of these PFAS-containing products are still lying dormant in cellars or workshops, but should not simply be thrown away, but must be disposed of properly.

• How can I recognize fluorinated waxes?

  All older waxes sold under designations such as "LF", "HF", "FC", "Cera F" or "Fluoro" generally contain PFAS and should therefore be disposed of properly. There is no general EU-wide labeling requirement for fluorinated ski waxes, which is why you should give preference to products that are explicitly labeled as "PFC-free" or "PFAS-free".

• What needs to be disposed of?

  Everything that has come into contact with the wax, such as old wax blocks and powder, sanding fleeces, brushes, wax cloths, shavings and scrapings.

• Where to put it?

  Fluorinated waxes and all materials contaminated with them are considered hazardous waste. They should therefore be taken to a recycling or reusable materials center that accepts hazardous or problematic materials .

  Important: Fluorinated waxes or contaminated objects must not be rinsed away with water - some PFAS are water-soluble and will otherwise be released directly into the environment.

• Why dispose of in hazardous waste?

  If disposed of improperly, PFAS can enter the environment via leachate from landfills. Waste water from waste incineration plants or sewage treatment plants, which cannot break down PFAS, can also lead to them entering soils, rivers and ultimately drinking water.