That page is hardly a reliable source, given that its "evidence" is the existence of pilots who died prematurely of heart conditions and suicides, an anonymous letter scanned from a self-published book, a conveniently unavailable video, a bunch of slides without citations, the presumption that a lack of official information about a supposed previous event (which has all the same hallmarks of non-proof) is proof of a nefarious conspiracy, and a death report that mentions acute myocardial infarction and lethal levels of opioids from which we're somehow supposed to conclude that the actual cause of death was an airborne neurotoxin inhaled 50 days before.
"Undetermined" with lethal blood levels of opioids and acute myocardial infarction sounds to me a lot more like "either the heart attack or the overdose killed him, I'm not sure which" than it does "actually, he died from neurotoxins he was exposed to 50 days before which I conveniently left out of the death report". The only source used to even claim the connection is a doctor whose major paper on the subject tries to call itself "significant" despite having obviously non-significant p-values.
