The conflict of chemical weapons is the danger and ferocity of them, along with the possibility of accidental exposure. Not to mention the number of innocent civilians who have been killed by these weapons throughout history.
For example, the Nazis used Zyklon B gas on the Jews, and Saddam Hussein used many different poison gases and nerve agents on the Kurds. These weapons were not known by the general public until the gas chambers of World War II, even though they were used during World War I also. They were not used much in World War II because Hitler thought if he used chemical weapons the Allies would use them too. He had been previously burned by some chemicals and temporarily blinded, so he didn’t want to inflict that kind of pain on another person.
When people started to finally understand the chemicals and what they could do, a convention was held declaring a compromise to participating countries about how many chemicals and what kind of chemicals they could have. This convention was held by the United Nations in 1993; it was called the Chemical Weapons Convention (CWC). This convention was held after a decade of debate and negotiations. All of the one hundred and forty countries involved were happy to finally agree to ban the use of the weapons.
The agreement was for the total removal of chemical weapons, though it would not be immediate; the changes would take place over many years. The U.S. and other major countries agreed to the conditions and since then have slowly been reducing the number of weapons in their arsenal, though some will be kept in case of a national emergency. Eventually, in the future, there will be no need for chemical weapons and hopefully all countries will decide not to use them.