I don't understand what Tech vs Rec has to do with this? Just because you're wearing split fins doesn't mean you're less likely to die of exposure. I know this is in the "Basic" forum....but the point is the same. The OP asked about oxygen toxicity/narcosis as if they were the same thing and didn't clarify. A small discussion broke out involving the fact that since O2 is toxic WELL before narcotic pressures, the point is moot. This is fairly true in a recreational/basic forum. My point was simply expanding on something.
However, what has NOT been discussed is what the OP actually meant or why they are asking. In the world of trimix diving, O2's narcotic properties are VERY important. In the "Basic Scuba" forum, they're not. What I've been trying to establish is what the OP meant. The question showed CLEAR lack of an understanding of the basic concepts/jargon of oxygen toxicity and narcosis.....so what does op MEAN and what is op ASKING?
I think what the OP was asking is that how is it possible to suffer from oxygen narcosis when you can't breathe oxygen at high enough partial pressures to experience oxygen narcosis.