Insensitive. Incoherent. Blundering. Tone deaf. Morally incomprehensible. Historically illiterate.

All of these are ways we can describe White House Press Secretary Sean Spicer’s comments Tuesday in which he declared Syrian Pres. Bashar Assad actions worse than Hitler since:

You know, you had someone as despicable as Hitler who didn’t even sink to using chemical weapons.

Spicer has been pilloried, and rightly so, for apparently forgetting that Hitler was more than happy to use chemical weapons, just to exterminate concentrate camp (which Spicer stumblingly referred to as “Holocaust centers”) inmates in the millions.

But here’s another inconvenient historical truth that Spicer clearly didn’t know but that deserves highlighting: Sarin gas, the nerve agent dropped by Assad’s forces on a rebel-held town in Idlib Province, was first developed in 1938 by German scientists working for the chemical giant IG Farben.

As historian Richard Evans notes in the final volume of his magisterial trilogy on the rise and ultimate defeat of the Third Reich, the compound was named in honor of its discoverers: Schrader, Ambros, Ritter, and von der Linde. In mid-1939 the formula for sarin was turned over to the chemical warfare section of the Wehrmacht’s weapons office, which ordered mass production for wartime use.

While it is true that Hitler never ordered the use of chemical weapons against the Allies on the Western Front (chemical agents, though not nerve gas, was used in several battles against Soviet forces on the Eastern Front), sarin and other nerve gases were manufactured at factories which used concentration camp prisoners as slave laborers. Prisoners were also used to test the effectiveness of the agents.

Otto Ambros, one of the developers of sarin, went on to become the Nazis’ chief chemical weapons expert. He was convicted at the Nuremberg tribunals for experimenting on concentration camp inmates and overseeing one of the factories at the Auschwitz complex.

He was sentenced to eight years in prison. After his release from prison in 1952 he worked as a consultant for several American chemical companies, including R.W. Grace and Dow Chemical.

Oh yeah. He also consulted for the U.S. Army Chemical Corps.