Sean Spicer was "kinda sorta" right about Adolph Hitler the other day. "Der Fuhrer" did not use "military" gas on his own people, just gas chambers on Jews, homosexuals, gypsies, mentally retarded, slavic and other folks that he felt were not part of the "master race." But, most especially, the Jews.
You see, Hitler himself had fought in WW I and had, himself, be a victim of a gas attack and had spent almost a year recovering in the hospital. He hated the concept of using gas as military weapon and knew that if he used it then the Allies would use it.
In WW I the Germans had perfected the use of gas in two forms: chlorine gas that burned the skin and burned out the eyes. It will make you cry to see of the film from WW I where the victims are being led to chow or to the latrine single file, eyes bandaged, with their hand on the shoulder of the man in front of them.
The other was far more lethal: Mustard gas. It not only burned the skin and eyes, it burned out the lungs and would lay on the ground for about a foot (unless a strong wind came along to blow it away which wasn't likely in most forests) clinging to the grass and bushes. If a soldier came walking along he would stir it up again and the next soldier behind him got another good dose of it. Terrible stuff.
Anyway, Hitler did not use it for military use; only on civilians that he did not think would fit into the Third Reich. So, give Spicer a break. He was almost correct. He just left out the word "military."
BTW, you do know who manufactured the gas [Zyklon B (hydrogen cyanide)] that they used in the gas chambers don't you? Yepper; good old Bayer AG. Same folks who make our asprin today. They also invented such things as phenobarbital and heroin. Wikipedia has a good article on them at https://en.wikipedia.org/wiki/Bayer#World_War_II.
I guess that I think that sometimes we are a bit too quick to forget what happened in WW I and WW II. The USA did some really, really bad things back home in WW I. Maybe I will write about those one day just wake everyone up. :-) Or you can go watch Part III of "The American Experience - The Great War" on PBS. http://www.pbs.org/wgbh/americanexperience/