What protects the maker

Spice is not dangerous in the way a hot kitchen is. It has its own hazards and they are almost all airborne.

The dust is the hazard

Grinding and pouring generate fine airborne particulate, and fine organic dust is an irritant to the airway regardless of how pleasant it smells. A morning spent grinding without a mask is a morning of breathing it.

Repeated exposure is the concern rather than any single session. This is a chronic irritant question, not an acute one, which is exactly why people ignore it.

Capsaicin is its own problem

Ground chili is a different order of unpleasant. Airborne capsaicin causes coughing and streaming eyes at surprisingly low concentrations, and it transfers readily from hands to face, to a phone, to a door handle, to whoever uses the room next.

The specific mistakes are grinding chili in an unventilated room, and touching your face before washing. Capsaicin is not water soluble, so a quick rinse spreads it rather than removing it.

What to actually wear

A fitted particulate mask for grinding and for any bulk pouring, not a loose surgical one. Eye protection for chili. Nitrile gloves for chili and for anything strongly staining, turmeric in particular.

Ventilation does more than any of it. Grinding near an open window or an extractor removes the problem rather than filtering it at your face.

The mill and the noise

Mills are loud, and hearing damage is cumulative and painless at the time. If you have to raise your voice over it, it is loud enough to matter over years of use.

Also treat the mill as a mechanical hazard properly: unplug before clearing a jam rather than reaching in with the power on, which is the injury that actually happens in this craft.

References