If opioids could be sold for recreational use, I think they would be sold with a naloxone in one package, reducing the number of deaths from overdose.
It's surprisingly hard to OD with a clean supply, measured dosing, and emergency services on site. I don't think that clean, supervised drug use is actually any more dangerous than say... skydiving or bungee-jumping.
(It's actually hard to fatally OD with just one vaguely sober person an nasal naloxone, but that's more specific to opiates.)