https://en.wikipedia.org/wiki/Hyperoxia
This was a screenshot I took months ago while watching a Geology Hub upload on YT. It was a lightbulb moment for my understanding of mass extinction events, (the largest was 250ma). I’ve referenced this multiple times, so thought I might share. Perhaps you find it as interesting as I do.
The atmospheric pressure needs to be significantly higher for even pure oxygen to put you at risk of oxygen toxicity. I don’t think this graph is accurate.
I think the white paper it came from is referenced in the bottom left box.