Re: Your letter of 13 July 1942—A 19/95/1942
Dear Comrade Brandt!
On request SS Hauptsturmfuehrer Prof. Dr. Hirt, Strasbourg tells me:
“Mustard gas in a dilution of 1:100 is dangerous to human beings if it contacts the body in an adequate amount. Above all, mustard gas is dangerously effective to clothing, as is known, even when greatly diluted, especially in connection with dampness. Mustard gas touching the skin even in a dilution of 1:100 causes reddening, possibly it causes little cysts without effecting necrosis. That is, the effect is much weaker than that of pure mustard gas. In spite of that, coming in contact with the clothes in sufficient quantities, especially in the regions of perspiration as the armpit, or the inguinal region, it can have exactly the same effect as concentrated mustard gas. For this, only a trace of it is frequently sufficient. This I experienced in a laboratory accident with a chemical student, who touched his armpit with one of the rabbits only for a second and a reddening ensued which spread over the entire body the following day, however, without further consequences. In my opinion, only a place which can be temporarily evacuated by human inhabitants can be used for gassing. The use of mustard gas in the vicinity of food stores, especially grain dumps, has to be absolutely excluded because one cannot know to what extent the rats carry the mustard gas there. Only gassing of rat holes would be possible with full application of precautionary measures. How this will work out technically, I cannot of course determine. Proper experts would have to judge that. Probably the case may be the same as with other poisons used for the extermination of rats (Phosphor-arsenic, strychnine, etc.)—that means that the use of every type of poison has two sides. In spite of this, your idea to try the extermination of vermin by means of poison gas does not seem strange at all, but an expert on poison gas would have to determine if there are not other means of killing rats which are less harmful to human beings.”
With kind regards
Heil Hitler!
[Signature] Sievers
P. S. I shall talk over this matter thoroughly with Professor Hirt one of these days, and I will see which poison gas expert we might consult for the solution of the problem.
TRANSLATION OF DOCUMENT NO-098
PROSECUTION EXHIBIT 263