In case folks don't know what d8 is: https://www.popsci.com/science/delta-8-thc/

Unlikely, but there may still be a contamination or fraud issue like what lead to the horrible lipid pneumonia scare.

∆8 doesn't cause vomiting, even at high doses or when not balanced with CBD. If people are using products that have flavorants and aromatics (including terps) or sweeteners, I'd be much more suspect of those.

It seems very likely. This illness started manifesting itself only recently, and only in the US. Someone is putting something in the dank.