Climbing shoe rubber as a source of toxic pollution in gyms

https://phys.org/news/2025-04-chemicals-climbing-abrasion-lung-issues.html 

Those who climb indoors are doing something for their health. But climbing shoes contain chemicals of concern that can enter the lungs of climbers through the abrasion of the soles.

In a recent study, researchers from the University of Vienna and EPFL Lausanne have shown for the first time that high concentrations of potentially harmful chemicals from climbing shoe soles can be found in the air of bouldering gyms. In some cases they are higher than on a busy street. 

It was striking that the concentration of rubber additives was particularly high where many people were climbing in a confined space.

Hofmann concludes, "The levels we measured are among the highest ever documented worldwide, comparable to multi-lane roads in megacities."

In 30 pairs of shoes tested, the team found some of the same pollutants as in car tires. Among the 15 rubber additives found was 6PPD, a rubber stabilizer whose transformation product has been linked to salmon kills in rivers.

What this means for human health is still unclear. But Hofmann stresses, "These substances do not belong in the air we breathe. It makes sense to act before we know all the details about the risks, especially with regard to sensitive groups such as children."

Basically, go climb outside,  it is good for you.

Link to the actual article - https://pubs.acs.org/doi/10.1021/acsestair.5c00017 

Climbing gyms are big DNA sharing-zones.

Didn't show makers change up their rubbers last year because of these compounds?

J L wrote:

Didn't show makers change up their rubbers last year because of these compounds?

If that happened last year, 2024, it is not likely study results would reflect updated chemistries due to the timing of product cycles -

From the article -

To assess the levels of RDCs more broadly, additional samples (triplicate settled dust and triplicate foothold powder samples) were collected in four more halls, in Switzerland, France, and Spain. In addition, 30 shoe sole samples representing major brands and models were analyzed. All samples were collected between February 2023 and June 2024.

Cherokee Nunes wrote:

Climbing gyms are big DNA sharing-zones.

I want to go to your gym

This is just like the chalk use in a gym thread and the question is how much of any of this stuff is needed to be ingested to be harmful? I suppose if you wore a bag of it over your head you would have an adverse reaction but I doubt anyone would do that.Oh wait the sky is falling.

Filters?

Fresh air exchangers (heat/cooling exchangers) been a thing in buildings for more than 40 years.

I was always told "climbing is inherently dangerous".  I feel like that applies to the recent chalk/rubber threads.

Let's skip to the part where we yell about vaccines, masks and 'merica!

Leon Wright wrote:

I was always told "climbing is inherently dangerous".  I feel like that applies to the recent chalk/rubber threads.

Let's skip to the part where we yell about vaccines, masks and 'merica!

Chalk dust and other dusts don't require Rfk, jr approval for removal. Even harmful micro-irritants have been removed from prison and shown to improve micro-cultures in and out of prisons....

Oh, wait! I digressed to "make america gasp again"

I feel like this, and the silica chalk issue are the dust on the microscope of climbing health issues. A number of climbers die from falls and avalanches each year. Never heard of a shoe dust or chalk dust death. And the whole issue pretends that all the other contexts in which we spend time in are somehow safer. We encounter automobile pollution and other particulates in vastly larger quantities, for much more time (e.g., work, grilling, campfires, second hand smoke etc.). But if you are worried about the chalk and shoe dust, you should absolutely quit climbing, and go that safer place, wherever that is...

jay2718 wrote:

I feel like this, and the silica chalk issue are the dust on the microscope of climbing health issues. A number of climbers die from falls and avalanches each year. Never heard of a shoe dust or chalk dust death. And the whole issue pretends that all the other contexts in which we spend time in are somehow safer. We encounter automobile pollution and other particulates in vastly larger quantities, for much more time (e.g., work, grilling, campfires, second hand smoke etc.). But if you are worried about the chalk and shoe dust, you should absolutely quit climbing, and go that safer place, wherever that is...

Climbers spend a few hours a week in the gym. Climbing gym employees spend much more time in the gym, and not just for fun. Research like this helps us understand the existence of health hazards that may exist; further research could help inform the magnitude of the hazard and the resulting risk of harm. Once that's better understood, we can look at the costs and benefits of mitigating that risk. 

The existence of other risks doesn't negate the possible existence of this particular risk. If it's possible to cost-effectively address it, we should consider doing so.

jay2718 wrote:

I feel like this, and the silica chalk issue are the dust on the microscope of climbing health issues. A number of climbers die from falls and avalanches each year. Never heard of a shoe dust or chalk dust death. And the whole issue pretends that all the other contexts in which we spend time in are somehow safer. We encounter automobile pollution and other particulates in vastly larger quantities, for much more time (e.g., work, grilling, campfires, second hand smoke etc.). But if you are worried about the chalk and shoe dust, you should absolutely quit climbing, and go that safer place, wherever that is...

The levels we measured are among the highest ever documented worldwide

I stumbled on this yesterday and it's still fresh in my memory: https://youtu.be/WPyRAcdZHDo . We are lucky we don't live in/near those villages in Indonesia where tons of plastic is burned as fuel to make the nation's stable food.

Belay On wrote:

I stumbled on this yesterday and it's still fresh in my memory: https://youtu.be/WPyRAcdZHDo . We are lucky we don't live in/near those villages in Indonesia where tons of plastic is burned as fuel to make the nation's stable food.

We just have cleaner burning methods here, most plastic gets incinerated these days since China stopped taking it a few years back.

I have a cousin living in Indonesia (where they cook on burning plastic) and when we said we wanted to come visit they said to not come because of the filth! 

Funny to think back to the earliest climbing gyms in my area, which had literal shredded tires covering the floor, and a persistent haze of chalk dust hanging in the air. I’m sure I did some premature aging of my lungs back then.

My local gym now is pretty modern and the air handling seems great. No haze in the air. No smells. My lungs are somewhat sensitive but I have had no problems, even on a treadmill or stairmaster when I’m breathing hard.

I’ve wondered about the open-cell foam under the carpets. I feel like that stuff has a bad reputation for off-gassing over time. The local gym just replaced all of it, actually. Maybe I should ask about chemicals etc.

jay2718 wrote:

Never heard of a shoe dust or chalk dust death.

Lincoln Hall, the Australian mountaineer who notably was on the team that did the first ascent of the Norton couloir direct north face route on Mt Everest, died at home of mesothelioma (lung damage caused from exposure to asbestos).

After surviving being left for dead at 8700m on Everest, enduring an open bivouac, and self-rescuing!

Still waiting on a shoe dust or chalk dust death then.

The lawyers are circling. 

If you started a barefoot, chalkless gym, it would potentially change the culture.  And make iontophoresis really popular.

Iontophoresis: with the rubber dust it could put a bounce in your step

J L wrote:

Still waiting on a shoe dust or chalk dust death then.

Point taken.

It was a really unexpected and ironic way for someone like that to go out though, survive a lifetime of 8000er expeditions but the asbestos gets you.

J L wrote:

Still waiting on a shoe dust or chalk dust death then.

It’s not  like they are just going to keel over. More likely it will be some reactive airways (like asthma), emphysema, or pulmonary fibrosis, after years of exposure. Just ask the coal miners. Might be hard to definitively link it to climbing gyms, amongst other exposures.

The thing is your lungs are so redundant that you can lose an entire lung, and still have relatively normal function. Sure, you might be a little short of breath with hard exertion, but that’s about it. That’s why people with lung disease like pulmonary hypertension, emphysema, etc. get diagnosed so late.

And the fix is such an easy one. Just filter the indoor air. It’s not even expensive. Look up Corsi  Rosenthal box.