I wouldn't concern myself robomatic, the heat in a kiln is a lot higher than most stoves and fireplaces, so I would think that the more complete combustion that occurs in a kiln would render most stuff harmless.

The problem with some stoves and fireplaces is that the by-products of a less than complete combustion can escape into a room. Be it the by-products of burning volcanic ash or wood smoke, both have their inherent risks.