[smaudet]

Per my sibling comment, I think thought must be given to the likelyhood of distribution of a "channel" or material state, not just the fact that one exists.

Particularly, wood is fairly recognizable, and almost certainly not liable to spontaneously implode into a cloud of dust. Plus, I'm fairly confident it is biodegradable (even in dust form).

Not sure the same can be said for most other materials, such as cadmium, or the parent mentioned naturally occuring compound.

[timr]

Kind of a digression, but wood dust absolutely does present an explosion risk, when mixed in the right ratio with air. It's a thing that happens, and people worry about it in industrial settings.

https://www.youtube.com/watch?v=LPIZ5Movuiw

https://www.youtube.com/watch?v=70fZqHsEdMo