Many moons ago I was diving a wall in the red sea using 36% Nitrox. My buddy was on air. An eagle ray was spotted below us and he dropped down to 45m to get a closer look. He couldn’t understand why I was hovering at 35m and waving at him to come back up. Back on the boat it was a dohhh moment for the very embarrassed dive buddy. We had dropped to 50 on previous dives so he didn’t understand my problem. I had told him I was on nitrox and we had a max 30m plan but he was apparently a big fan of eagle rays and forgot in the excitement.
In UK conditions that would have ended in a couple of solo divers
As far as 02 tox is concerned you would rely have to take the piss to get a tox hit on 32 or 36%Nitrox Even staying at 35 for 10mins and doing 40mins at 30m I would only just tip over the 100% CNS figure.
ATB
Mark Chase