My mother is a physician, she just last night told me about a case she saw over the weekend in which a young 20-something nearly OD’d on fentanyl from taking ecstasy. She survived, but with life-altering brain trauma rendering her unable to remember who she is. She needs tubes for her food supply, and a ventilator to breathe.
Here you can see a few images of what is a lethal dose of fentanyl: https://www.dea.gov/galleries/drug-images/fentanyl
Scary stuff, and maybe there’s an argument there to be made in favor of legalizing current black-market drugs. Definitely a PSA to test your drugs.
CDC on cross-contamination: https://www.cdc.gov/drugoverdose/deaths/other-drugs.html