If you've ever walked into a climbing gym on a busy day, you know: the air is thick, almost milky. Every movement leaves behind a small white cloud. That's chalk, the same stuff you use for better grip on holds. But have you ever wondered what's really in that powder you're breathing?
In recent years, several studies have analyzed the composition of commercial chalk and its suspended dust. The results? Not exactly reassuring.
A study published in Environmental Science and Pollution Research found the presence of heavy metals such as aluminum, iron, nickel, chromium, arsenic, and lead in chalk sticks. Some of these, particularly arsenic, chromium, and nickel, are potentially carcinogenic if inhaled regularly, especially in children, who have higher exposure relative to their body weight.
Another study, conducted in school environments, confirmed that chalk dust can contain harmful elements such as manganese and cobalt. Although the concentrations are low, repeated exposure in enclosed, poorly ventilated spaces can accumulate over time. Children and people with respiratory conditions are the most vulnerable.
But it's not just about chemical composition. Particle size also matters: finer dust remains suspended in the air for a long time and reaches our lungs directly. In climbing, this means you're breathing not only chalk, but a mix of trace elements with toxic potential.
However, there's no need to abandon your chalk bag. Simple and accessible solutions exist:
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opt for liquid chalk or coarse-grained chalk
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choose chalk that is as pure as possible or even synthetic
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if you manage a gym, invest in a good ventilation and air filtration system
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avoid "clapping" your hands creating unnecessary clouds
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brush holds after use and regularly clean surfaces.
As in any sport, knowing the risks helps you enjoy the activity more consciously. And when breath becomes short, it's good to know that the solution isn't just a firmer grip, but also cleaner air.
Further reading:
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Heavy metals analysis in chalk sticks based on ICP-AES and their associated health risk - https://link.springer.com/article/10.1007/s11356-020-09884-w
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Trace Elemental Characterization of Chalk Dust and Their Associated Health Risk Assessment - https://link.springer.com/article/10.1007/s12011-016-0769-1
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Potential health benefits and risks associated with bouldering, a sport of rapidly increasing popularity – a literature review - https://apcz.umk.pl/JEHS/article/view/57780/41665
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Reducing dust exposure in indoor climbing gyms - https://pubs.rsc.org/en/content/articlelanding/2012/em/c2em30289f
