We have only the experience of many thousands
Well, die off is actually a kind of poisoning. Again, all that we have is anecdotal, subjective evidence ... but we have loads and loads of it.
First, there is the testimony of Humble and those who have worked along with him ... many tens of thousands worked with, and his accounts of the diarrhea and vomiting that occur as excess die-off.
Second, I have my own personal testimony ... too much NaClO2 and I got die-off (temporary) symptoms, including D and V which quickly went away when dosage was reduced; a small, consistent amount and I became very healthy over time.
Thirdly, we have the anecdotal stories of many thousands that have been using NaClO2 in lesser concentrations for many years. And this number truly does run into the tens of thousands also. These people have, in general, had similar experiences with NaClO2 ... cleansing reactions, sometimes too harsh if overdone, and improved health. I know many people like this (over a hundred), and know of many others.
Fourthly, we have the personal stories of all those who have been using
Miracle-Mineral-Supplement and posting information accross the web since Humble's book first came out ... there are many sites with information now ... and as far as I have seen not one case of poisoning.
And, even though I said that all we have is anecdotal evidence, that is not quite accurate; we also have many studies about the safety of Chlorine Dioxide for use in purifying drinking water, and purifying food products, for ingestion ... these studies have been repeated over and over again by various scientific establishments. I put this last because I actually have the least trust in it.