Ridding the world of chemical weapons proves challenging

While most of the world has agreed to destroy these deadly weapons, the attack in Syria this week shows the urgency of the situation, writes Caroline Alexander

The first agreement to ban chemical weapons came in 1675. (France and the Holy Roman Empire forswore poisoned musket balls.)

Three centuries and at least six international treaties later, they are still being employed, and there’s little the world can do to stop it.