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Lethal HCN Concentration For Humans

Posted: Fri Jul 17, 2026 6:48 pm
by Stubble
There is much talk of '300ppm' being 'rapidly lethal' for humans. You will find this number bandied about by Holocaust Enthusiasts. The data this is based off of is clearly corrupt.

While looking for a handy dandy chart that I have some place showing an LC-50 for 300ppm equating to half an hour (this chart too is likely dubious) I noticed that Germar in The Chemistry of Auschwitz made a formula that can be used to calculate lethal concentrations which conforms roughly to real world data from American Gas Executions.

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This can be found on page 234 of The Chemistry of Auschwitz, although the whole section is worth reading beginning from page 230.

Needless to say, the supposed 300ppm, while conforming to OSHA safety guidelines, is quite conservative when balanced against execution data.

I don't recall the forum having a thread on this so I leave it here for posterity.

Re: Lethal HCN Concentration For Humans

Posted: Fri Jul 17, 2026 8:46 pm
by Wetzelrad
It is a recurrent myth worthy of a thorough debunking. Germar Rudolf did that using data from several other publications. See The Chemistry of Auschwitz, pages 230 to 236. Anyone who believes the 300 ppm myth is welcome to read and try to refute Rudolf's sources and arguments here.

For more accurate numbers, I highly recommend his Table 16. Column 7 (CA) is the concentration needed to achieve death based on U.S. executions, and column 8 (CAeff) is that with the added factor of ongoing oxygen depletion.

table cyanide concentration for Crema II.png
table cyanide concentration for Crema II.png (363.67 KiB) Viewed 25 times

According to these calculations, the real HCN concentration needed for the alleged 5-minute executions would be 13,000 ppm. Even if you dispose of those witnesses and go for 15-minute executions, it would require 3,000 ppm.