New military technologies developed during World War 1 made warfare deadlier and increased casualties. The tank was first proposed by Colonel Ernest Swinton and secretly developed by Wilson and William Tritton, producing the first armored vehicle that could carry a crew of three and travel over 3 mph. Poisonous gases were first used in the war by Germany against France, with mustard gas causing severe burning and a slow, painful death. Germany also pioneered the use of the flamethrower, which could project streams of fire up to 40 meters and burn soldiers out of trenches, though these weapons were dangerous to operate and of limited duration.