A long, brutal history: How dangerous are chemical weapons? The Vietnam War is only one of the example of dozens of cases where chemical warfare was used on battlefields, starting early enough from the beginning of the 20th century. The most recently confirmed use of chemical weapons was on April 4, 2017, sarin was used in the Khan Shaykhun area in Idlib Province of Syria. Sit back and watch this video. CGTN is a taking you back to the long and brutal time where chemical weapons were used and in