A three year old girl was killed in an Iraqi town last week after an ISIS attack that reportedly used chemical weapons. Several others were rushed to the hospital in critical condition, 400+ residents of the town were exposed and are facing respiratory problems and burns. This is not the first time that ISIS has used chemical weapons, in fact they may have been in use as early as 2014, while it has been confirmed that ISIS used them in August 2015. This attack was perpetrated by weapons loaded with mustard gas, which is sometimes considered nonlethal, although it has shown a certain capacity to kill and can lead to multiple symptoms that may cause death . Mustard gas was first effectively used by the Germans in WWI and was outlawed in 1925 by the Geneva Protocol.
If ISIS is looking for something to further unite the world against them, using illegal chemical weapons to kill innocent civilian children is a good place to start. The US captured the chemical-weapons expert for ISIS and has interrogated him, but that has apparently not yielded the desired results. If attacks using chemical weapons continue to become a theme with the so called Islamic State, I expect the number of airstrikes to continue to increase, and the number of countries involved to steadily increase as well.