Well, then, let me restate.
The rate of accidental ODs from heroin is VASTLY higher than the rate of accidental ODs from OC because of the purity control of OC vis a vis heroin. Is that more to your liking?
I would wager that the rate of intentional OD from OC is a lot higher than for heroin because of the preference for suicide actors to pop pills instead of inject. But, the rate of Tylenol OD is the highest of any drug, so intentional ODs are really not relevant to this discussion which was about the objective "safety" of drug usage. Tylenol is very dangerous if intentionally abused, but it carries FAR less risk of death from accidental OD than does heroin. Cuz, nobody really knows wtf is in street junk and Tylenol's content is rigorously controlled. Unless you cooked it yourself from a pharmaceutical source of morphine, you've got no idea what heroin's potency or cutting agent content may be.
But, OC is a safer drug than heroin, despite the obvious chemical similarity and relatively similar potency, because OC's purity and content can be determined with certainty. That's really my fundamental point. *Accidental* ODs happen when people get messed up stuff or other cofactors conspire.
When I think of "OD," I don't think of "suicide attempt." Most people don't either; they harken back to the fright stories about "don't use drugs, because you might OD and die," the tales about crack users ODing and dying on their first hit and stuff like that. The term OD is oft-used in conjunction with accident and far less so in conjunction with suicide attempts. Usually, they leave off the drug and the term "OD" when discussing suicide, because they'd scare the goddamned nation to death over Tylenol. In terms of suicide, drug=hanging=gunshot (highspeed lead overdose).