The worsening situation in Syria, 17 months into its political crisis, is heightening international fears over the nature of its chemical-weapons programme and the security of its stockpiles. Though Syria's efforts to develop chemical weapons are shrouded in secrecy, it is thought to have the largest arsenal in the Middle East and probably the fourth-largest in the world. The possibility that chemical weapons could be used against Syrians or foreign forces, or that the security of weapons or nerve agents could be compromised and fall into the wrong hands, is causing considerable alarm, particularly in the region.
Damascus is equally secretive about its development of other non-conventional weapons. Its nuclear programme was exposed following an Israeli airstrike on Al-Kibar in 2007, while even less is known about the extent of any biological-weapons development efforts.
Following a series of embarrassing Arab military defeats in the 1970s and '80s at the hands of a strategically superior Israel, Syria began investing in military expansion, modernisation and restructuring in the 1980s in an attempt to achieve strategic parity. But Syria could not compete with Israel's conventional superiority, especially at a time of economic difficulty and after the loss of its Soviet patron. Instead, Syria boosted its support to proxy groups in the Arab world and strengthened its alliance with Iran. It began to develop its chemical-weapons programme and is also thought to have embarked on the research and development of a biological-weapons programme.
Sometimes branded 'the poor man's atomic bomb', chemical weapons are not effective on the battlefield and could not be used pre-emptively against Israel. Although they do form part of Syria's military doctrine, ensuring their effective deployment and even distribution in targeted areas would be complicated. The utility of chemical weapons lies in their ability to cause terror and disruption, particularly in population centres and behind the frontlines in times of conflict. This was deemed enough to deter Israel.