I was wondering if someone would mention this. I grew up in the Blue Ridge Mountains of NC and heard this all my life. Once had a camp councilor who would inspect every twig to make sure there was none burned.

I also burned Rhododendron wood in campfires and brush fires more times than I can count without any adverse effects that I know of. My back yard was completely overgrown with the stuff. I’m sure the smoke inhalation of any fire is worse for you than anything specific about rhododendrons.

https://outdoors.stackexchange.com/questions/7100/are-rhodod...