Syria: West may be forced to seize Bashar al-Assad's toxic gas stockpile Like Israel, Syria has not signed the Chemical Weapons Convention of 1997, nor is it a member of the Organisation for the Prohibition of Chemical Weapons, which verifies stockpiles of these weapons. Outside experts say that Syria's chemical weapons programme dates back to the 1970s and ranks among the most advanced in the Middle East. However, Mr Assad is not believed to possess any biological weapons. The rationale for his arsenal is to counterbalance a nuclear-armed Israel on Syria's western flank and a NATO-allied Turkey on the northern frontier. Experts believe Mr Assad is highly unlikely to use these munitions against his domestic opponents. Whether Syria's armed forces are fully trained in their use is also questionable. Dina Esfandiary, a non-proliferation specialist at the International Institute for Strategic Studies, said that little was known about the full extent of Syria's chemical weapons stockpiles. "It's worrying because we don't know," she said. We don't know exactly what Syria's capability is. We don't know how big their stockpiles are - or where they are. It would be difficult for everybody to secure them, particularly if factions within the country are fighting eachother. Ms Esfandiary added: "The risk of the agents falling into the hands of non-state actors is quite worrying." America has identified "at least a dozen or so sites that have some very serious chemical weapon caches," said Mike Rogers, a Republican Congressman who chairs the House of Representatives Intelligence Committee. He told CNN that the attendant risk "keeps me up at night." The al-Safir military complex, near the city of Aleppo, is understood to be one site where chemical weapons are stored. Satellite imagery of the location "offers substantive evidence that Syria maintains and continues to upgrade a chemical weapons programme," according to Jane's Intelligence Review. Al-Safir is protected by SA-2 surface-to-air missiles and contains 16 storage bunkers, according to Jane's, which adds that Syria "continues to enhance its ability to deliver both conventional and chemical warheads." The country is believed to possess 700 Scud missiles, one of the biggest such arsenals in the Middle East. The evidence suggests that Syria has adapted these weapons to deliver chemical warheads. In 2007, an explosion at another plant killed 15 scientists and engineers as they tried to load a chemical warhead on to a Scud. North Korea is known to have helped Syria's missile programme and may have aided the development of chemical weapons. Mr Assad could also have received help from Iran, his closest ally.