Mustard Gas is a group of chemical compounds used in chemical warfare, so called because of its mustard-like smell. Mustard gas contains carbon, hydrogen, and chlorine, with either sulfur or nitrogen. When it comes in contact with skin, mustard gas causes severe blisters. Clothing can be worn to protect the skin, but breathing it produces extreme damage to the lungs and other internal tissues. These compounds are particularly harmful to moist areas of the human body, such as the eyes, armpits, and groin, and concentrated exposure may be fatal. Mustard gas is generally a solid or liquid, but can also be sprayed as an aerosol. Modern gas warfare began during World War I (1914-1918). In April 1915, after several experiments using tear gas, German forces used chlorine gas against British and French troops in Ieper, Belgium. The Germans set up a series of cylinders filled with chlorine gas along their front line. Opening the cylinders, they released a cloud of chlorine gas that the wind carried to their enemy's front line. Thousands of Allied troops succumbed to the effects of the gas, and because of this devastation, the gas became an instrument of psychological as well as physical warfare. Protective equipment such as gas masks was soon issued to troops. This solved the problem mainly, but still did not give complete protection.
In September 1915 the British initiated a gas attack against the Germans. Some of the British troops were inadvertently exposed, and this led to the rapid development of projectiles filled with gas that could be fired into the enemy's trenches from a safer distance. German chemist Fritz Haber supervised the first use of chlorine gas by the German military in 1915. Later, he directed the production of a deadlier form of gas, phosgene, as well as mustard gas. Mustard gas, first used in 1917, proved more stable than chlorine gas and phosgene, and could contaminate an area for days after its release. (Apparently those military scientists and leaders think more destruction is better. This just shows how sick the world is.) 
I am really against mostly all forms of violance, so spraying mustard gas on fighting soldiers would not get my support. I think it is ridiculous that military scientists and military leaders think that more harm is better. For all those sick, violant military people, I suppose mustard gas could be a useful tool of destruction. After all, it hurts and kills, and that's what the military is all about. In closing, I just want to say that instead of bombing countries and using chemical warefare, we should be spend more time trying to unite countries, work out disagreements and avoid war. I know I was supposed to mainly talk about my opinion on mustard gas, but mustard gas has to do with violance and war, and violance and war have to do with my opinion above. 