The second battle of Ypres was the first time people (German)used chlorine gas as a weapon. Germans had on gas masks(which they invented)when they used chlorine gas as a grenade. This weapon was illegal in war and if you were caught with it you would be killed. 6,000 people died of suffer-cation due to gas or from the ensuing attack. The interesting fact is that although the Germans were unfair the Canadians held their ground and never lost to Them.