<P> On 24 September, Baralong destroyed U-41, which was in the process of sinking the cargo ship Urbino . According to Karl Goetz, the submarine's commander, Baralong continued to fly the US flag after firing on U-41 and then rammed the lifeboat--carrying the German survivors--sinking it . </P> <P> The Canadian hospital ship HMHS Llandovery Castle was torpedoed by the German submarine SM U-86 on 27 June 1918 in violation of international law . Only 24 of the 258 medical personnel, patients, and crew survived . Survivors reported that the U-boat surfaced and ran down the lifeboats, machine - gunning survivors in the water . The U-boat captain, Helmut Patzig, was charged with war crimes in Germany following the war, but escaped prosecution by going to the Free City of Danzig, beyond the jurisdiction of German courts . </P> <P> The first successful use of poison gas as a weapon of warfare occurred during the Second Battle of Ypres (22 April--25 May 1915). Gas was soon used by all major belligerents throughout the war . It is estimated that the use of chemical weapons employed by both sides throughout the war had inflicted 1.3 million casualties . For example, the British had over 180,000 chemical weapons casualties during the war, and up to one - third of American casualties were caused by them . The Russian Army reportedly suffered roughly 500,000 chemical weapon casualties in World War I . The use of chemical weapons in warfare was in direct violation of the 1899 Hague Declaration Concerning Asphyxiating Gases and the 1907 Hague Convention on Land Warfare, which prohibited their use . </P> <P> The effect of poison gas was not limited to combatants . Civilians were at risk from the gases as winds blew the poison gases through their towns, and they rarely received warnings or alerts of potential danger . In addition to absent warning systems, civilians often did not have access to effective gas masks . An estimated 100,000--260,000 civilian casualties were caused by chemical weapons during the conflict and tens of thousands more (along with military personnel) died from scarring of the lungs, skin damage, and cerebral damage in the years after the conflict ended . Many commanders on both sides knew such weapons would cause major harm to civilians but nonetheless continued to use them . British Field Marshal Sir Douglas Haig wrote in his diary, "My officers and I were aware that such weapons would cause harm to women and children living in nearby towns, as strong winds were common in the battlefront . However, because the weapon was to be directed against the enemy, none of us were overly concerned at all ." </P>

Who was all involved in world war 1