Spider wrote:
I doubt that there will be enough to be serious, because hydrogen
cyanide is extremely flammable, with a flash point of -18. See:
Interesting link. Thanks, Nick. All the same, it describes it as
pretty nasty. I would like to think most people would have the sense to
avoid smoke, but I have seen gardeners stubbornly standing in a cloud of
smoke whilst prodding their bonfire. Until the fire becomes hot enough
to reach that flash point (or repel a dozy gardener), surely toxic
vapours will escape? I wouldn't want to risk it.

I'll be quite impressed if you can get your fire burning lower than -18!