Despite their popularity, some believe that using chalk to label food jars can create unnecessary dust that can get into the food, is this a real concern, or has technology advanced enough where this is not a problem? Maybe the amount of chalk used on the label is not enough to kick up dust? What about accidental contact when handling the jar?
There certainly will not be enough chalk-dust-kick-up to warrant any safety concerns through inhalation or otherwise. The only concern I could think of would be to have to constantly rewrite labels after handling!
There are 'chalk pens' which I've seen sold with those labels. They're liquid, like a paint pen, so there's no dust.
Unfortunately, there's typically a warning on the packaging that they're not erasable if used on chalkboards ... and it might be true for the labels as well. ... which would defeat much of the purpose of using the stickers in the first place, as they're then just decorative and not functional.