[An.American.Expatriate]

"The first killing agent employed by the German military was chlorine. Chlorine is a powerful irritant that can inflict damage to the eyes, nose, throat and lungs. At high concentrations and prolonged exposure it can cause death by asphyxiation.[8] German chemical companies BASF, Hoechst and Bayer (which formed the IG Farben conglomerate in 1925) had been producing chlorine as a by-product of their dye manufacturing.[9] In cooperation with Fritz Haber of the Kaiser Wilhelm Institute for Chemistry in Berlin, they began developing methods of discharging chlorine gas against enemy trenches.[10][11]"

1915: Large-scale use and lethal gases

[IYAS9YAS]

German chemical companies BASF, Hoechst and Bayer (which formed the IG Farben conglomerate in 1925)

BASF, they don't make the products that kill you. They make the products that kill you better.