Toxic chemicals are known to have been used in warfare for thousands of years in various shapes and forms but it was WW1 that they were used on a more industrial scale. They are at least 20 known gasses that were manufactured but we are just outlining, briefly, an introduction of 3 of the main gasses used were, Chlorine gas, Phosphene gas and Mustard gas. It was the French that first used a gas in WW1. They were known to use tear gas rifle grenades against the Germans as early as August 1914, though these were pretty ineffective. Later in 1914, the Germans initiated their first use of gas which was based on Chloro-sulfate which was known to irritate the lungs. This was used against the British but fortunately all the gas was pretty much burnt up by the explosive charges so the British had not realised they were attacked chemically. The British first used gas at the Battle of Loos, Sept 1915 but this was disastrous. They used a Chlorine gas that relied on the wind to blow it across the German lines but that day, the wind only blew the gas over no mans land then it turned and then blew the gas back over the British lines.
This gas did not kill or wound immediately, its affects would normally take place 24 hours later. It was a colourless gas that, although pretty odourless, was likened to mouldy hay. Affects from exposure to Phosgene gas were coughing, watery eyes, blindness, burning throat and lungs. This was the most effective gas used during WW1.
Yellow/green in colour, this gas was very toxic and would be irritant to eyes and skin, cause shortness of breath and vomiting and lung damage.
Known as the ‘King Of Gasses’, first used by the Germans in 1917. It was yellow in colour and killed by blistering the lungs and throat if inhaled. It was a heavy gas that sunk intothe trenches and soaked into the soldiers heavy woollen uniforms also causing blistering of the skin.
All these gasses could lead to death and by the end of WW1 over 1,000,000 casualties were attributed to gas warfare alone. Most of the chemicals manufactured during WW1 were never used.
The use of poisonous gasses by all major belligerents during WW1 constituted war crimes as their use violated the 1899 Hague Declaration Concerning Asphyxiating Gasses and the 1907 Haig Convention On Land Warfare. These prohibited the use of poison weapons in warfare.