As a doctor, I find it hard to understand why or how a substance that is generally unreactive could cause health problems in the human body. Generally, the less reactive a substance, the less it causes health problems e.g. helium (sure, if you breathe a “hypoxic mixture” of 100% helium, you die, but thats from lack of oxygen, not the helium itself).

Any biochemists out there who can tell me if I’m missing some important context?