Universität Stuttgart Abteilung Wirkungsgeschichte der Technik, page 5
The Allies responded shortly after the German gas attacks with their own chlorine gas attacks: The English blew 150 tons of chlorine gas off at Loos in northern-east of France on 25 September 1915, by what the German front was ripped on a width of 12 kilometer, but without a breakthrough of the front.
Grenades with phosgene fillings were first applied by the French at the bloody combat at Verdun in February 1916. The impact was disastrous, it was described by the doctor of German pioneer- regiment No. 35, Alfred Schroth: "After inhaling a deadly dose, the respective person only feels a light tickle in his throat and eyes. This normally goes by fast and within two hours until maximum 3 days the victim might have no discomfort at all.[...] Finally, the victim reaches a state in which he cannot inhale enough oxygen. He collapses, his breathing is accelerated, flat and spasmodic, he develops strong feeling of oppression and his secretion is yellowish. This state of destruction is followed by death [author translation]."12
Soon, a German answer followed by using diphosgene / perstoff called "Green cross". 13.800 grenades were fired at the battle towards Verdun on May 7th 1916 and 13.000 grenades on May 19th 1916 against the French trenches at Chatancourt. Furthermore, 127.000 grenades were fired on June 22nd and 23rd 1916 at artillery battle in Fleury close to Verdun.13On 4 April 1917 the English troops used in the battle of Arras mortars with gas-mines, so called Livens projectors. With electrical combustion some hundred gas- mines were simultaneously thrown towards the German frontline. A very high concentration of the poison was developed and the gas eliminated the sound air nearly completely what made the respirators of the German servicemen soon ineffective.
Martin Gutmann