Chalk, and the places that restrict it.

What chalk is

The UIAA's list of equipment standards has none for chalk, so its description here comes from a maker. Mammut, in a guide dated June 2024, describes climbing chalk as magnesium carbonate (MgCO3), mixed with water or magnesium hydroxide, which absorbs moisture to keep hands dry. It says the mineral occurs naturally as magnesite and is mined and processed. These are Mammut's statements.

The three forms

Mammut notes that the alcohol in liquid chalk can irritate sensitive skin or open wounds, and that alcohol-free versions exist. Wikipedia gives a similar description of liquid chalk and says some climbers prefer it because it lasts longer and leaves less residue and dust.

Chalk indoors

Mammut says many indoor gyms post "no dust" rules because chalk powder harms air quality and leaves residue on holds, and that some gyms require chalk balls or liquid chalk. Rules differ from gym to gym; this site does not list individual gyms.

Chalk on rock: what a maker says

Mammut's 2024 guide says that chalk can harm plants, that trapped moisture can freeze in cracks and make rock, especially limestone, crumble, and that too much chalk builds up a slippery layer. It encourages using little chalk and brushing residue off holds with brushes that are gentle on the rock. Mammut also says some regions restrict chalk in designated areas and that some areas in Europe ban it entirely; our research did not find those European rules published by a land manager, so they are not listed here.

Published chalk rules

Two sets of rules were confirmed, both in the United States.

Arches National Park (National Park Service)

The NPS rock climbing page for Arches National Park, last updated 28 July 2026, prohibits white chalk and requires any chalk used to be similar in colour to the rock being climbed. The same page sets colour rules for other gear left on the rock:

• Bolts, hangers and chains must be painted the colour of the rock or primed brown before they are installed.
• Slings or other soft gear left on a route must match the rock colour.

It also prohibits chiselling, gluing existing or new holds, and deliberately removing lichen or plants. A December 2019 NPS news release for Arches and Canyonlands, seen in a search summary, repeated the chalk-colour rule. The bolts page covers the park's fixed-gear permit rules.

Garden of the Gods (City of Colorado Springs)

Garden of the Gods is a city park, managed by the City of Colorado Springs Parks, Recreation and Cultural Services Department, not by the National Park Service. According to reports by Climbing magazine and the local station KOAA, the city banned climbing chalk and chalk substitutes of any kind or colour in the park from 15 March 2021, extending an earlier chalk ban. The city cited increased climbing and chalk use and worked with the Pikes Peak Climbers Alliance. We could not find the city's own page, so whether the ban is still in force is unconfirmed.

The wider principle

The National Park Service lists the seven Leave No Trace principles, which it says were set by the Leave No Trace Center for Outdoor Ethics; one of them is to leave what you find. The access and ethics page covers access rules and closures more broadly. Rules change, and the land manager's current page is the authority for any area.