I have a natural gas furnace in the workshop which has a constant-on
pilot light. I would think that the concentration of dust would have
to be extremely thick before an explosion would ignite, but I do want
to be safe.

I used to have a open flame propane heater next to my bandsaw before I had a dc.
all it did was burn the sawdust. you really need a cloud to get anything. if you
had that much of a cloud you could not work in the shop.

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