Pure oxygen is toxic. Read up on it
Better than reading up on it, is to do the experiment yourself. That’s what makes it “scientific” or the scientific method — that anybody can run the experiment and verify the results for themselves. Otherwise, one is just accepting authority — and not that one has ever discovered any truth for themselves.
Besides, I did not advocate using pure oxygen — which as a practical matter is inaccessible to most people, nor did I advocate forcing it into the body under pressure. I simply said one could enhance the oxygen in one’s environment in a very simple, cheap, undeniably effective manner — with all kinds of unanticipated benefits — including maintaining a hygienic environment in this manner. Then breathing those vapors into the body, has that same effect of enhancing the body’s ability to handle bacteria, viruses, fungi, mold spores, allergens, etc. — before spending one’s fortune treating each symptom as though it is unrelated to every other.