Is Chalk Dust Harmful?

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  • Written By: Michael Pollick
  • Edited By: Niki Foster
  • Last Modified Date: 27 September 2019
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There are two separate issues buried in the question of chalk dust safety. In one sense, the main ingredients of this dust are considered to be non-toxic, which simply means they do not pose a threat when ingested. In another sense, this material can and does accumulate in the human respiratory system, which means it can create long-term health problems due to overexposure. In short, swallowing a piece of white chalkboard chalk won't kill a person, but breathing in the dust for a number of years can create or trigger respiratory problems.

Chalk dust is the natural by-product of using a chalk crayon on a blackboard. As the chalk is scraped across the rough surface of the board, particles of it are sent out into the surrounding air. Some of this dust settles to the ground or is ventilated outside, but much of it falls on clothing, furniture, electronic equipment and shelves. Teachers and students also inhale a portion as well, which usually becomes trapped in the mucus layers of the throat and upper lungs.


A small amount of inhaled dust is not considered harmful. Those with healthy respiratory systems can expel it through coughing, and the remaining material should be absorbed safely into the body. For those with chronic breathing issues such as asthma, however, exposure can trigger a reaction. In fact, many school systems strongly urge teachers to move students with respiratory problems away from the chalkboard area. Chalkboards, trays and erasers filled with dust should also be cleaned regularly.

Standard chalk for classroom use is generally made from calcium carbonate, a processed form of natural limestone. The traditional method of creating white chalk was to form a clay-like paste with the calcium carbonate and allow it to cure in chalk-shaped molds. This chalk worked well with slate chalkboards, but it also generated a significant amount of dust that floated into the surrounding air. Teachers who used traditional chalk for a number of years developed some respiratory problems, although not generally considered severe.

There is now a product called dustless chalk, designed to address the chalk dust issue. Instead of forming crayons through individual molds, the new chalk mixture is extruded into ropes, then cut to size and allowed to dry. This dustless chalk does generate a form of dust, but the particles are much heavier and tend to fall directly to the floor instead of floating in the air. Exposure to airborne particles has been reduced, but the accumulation of dust elsewhere is still problematic.

Beyond the human health aspects of chalk dust exposure, there are also potential electronic hazards. Devices such as computers and digital versatile disc (DVD) players stored inside classrooms can suffer damage from accumulated dust. As the chalk particles circulate throughout the room, cooling fans may draw them into the computers' inner workings. As it builds up on the motherboard and other heat-sensitive parts, the risk of overheating increases. This dust can also cause severe damage to sensitive electronics, such as the laser reader of a DVD player or the playback heads of a video cassette recorder (VCR).

Chalk dust is considered an irritant and an occupational hazard by a number of occupational safety organizations around the world. People who must work around it for extended periods of time may want to use a filtered mask over the mouth and nose and taking a number of breaks in a fresh air environment. They should also use other dustless methods of communication, such as dry erase boards or overhead projectors, whenever possible.


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Post 14

I have an addiction to eating white chalk. I have to have at least five pieces a day, sometimes more. I have been eating this chalk for the past year now. Has this chalk damaged my insides by any chance and what should I do to stop myself from eating it?

Post 13

If my generation still hasn't developed an epidemic of lung cancer or COPD, I'd say we're pretty safe. I know we breathed in a *lot* of chalk dust when we cleaned the erasers.

My dad was left-handed and a teacher. He hated the dry erase boards. He smeared it, but never did with chalk.

Post 12

Though I imagine given our bodies are designed to deal with a lot of dust (see, planet earth), I don't know if it was designed to really inhale a lot of the same kind of dust.

Perhaps the only good thing about "real" chalk is that it is a natural product, that it is basically finely ground up rock. I'm more concerned about the effects of exposure to black marker chemicals. Though essentially they are organic alcohols and thus "natural" byproducts, I don't think nature ever meant their fumes to be up in our noses after we've processed them into pure liquid form. Did you know kids regularly get high off of just smelling plain old markers?

I think we should stay with chalk in classrooms, at least for younger children. In fact, many university professors prefer a chalkboard.

Post 9

What about the lead that has been found in so many sidewalk chalks?

Post 8

I use dry erase markers daily and, at the end of the day when I blow my nose, the mucus sometimes has a black color. I always felt safer with chalk.

Post 7

if the chalk used for keeping the ants away is swallowed, does it have a harmful effect on the body?

Post 6

Dust fling up in the air will do harm to respiratory system, because of the conventional making method of chalk. The main ingredients are calcium carbonate or lime. now a new kind chalk, named Biaxi, absolutely finishes the dust, and is welcomed by teachers and students in China. Seeing is believing!

Post 5

Now we need to know what breathing in dry erase marker dust does to teachers. Seems like it would be a lot more dangerous. My hands are black. The black dust accumulates everywhere, even in our lungs.

Post 4

I have heard that the DustEZE electric chalkboard chalk eraser and dust vacuum cleaner can clean chalk eraser dust very easily. Does anyone know where to buy it?

Post 1

what are the ingredients of chalk which is used to get rid of ants?

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