"adam russell" wrote

The gasses you describe which 'make you nauseous' are literally quite
dangerous in concentration.

Ok thanks. But just to be clear, it smells to me like chemical smell, not
sewer smell. I wouldnt have thought that it came from the toilet. You
still think yea?

Perhaps SteveB has better advice? He seems to work in this field and
mentioned the corroded bolts like I did, but is probably a much better
plunmer than I am!