"Syria has produced, stored, and weaponized chemical agents, but it remains dependent on foreign suppliers for chemical precursors. The regime of President Bashar al Asad possesses stocks of nerve (sarin, VX) and blister (mustard gas) agents, possibly weaponized into bombs, shells, and missiles. The government also has associated production facilities. Chemical weapons and their agents can deteriorate depending on age and quality; little is known from open sources about the current condition of the stockpile. Syria continues to attempt to procure new supplies of chemical weapons precursors, which are dual-use, through front companies in third countries. […] A major policy concern of the United States has been the use or loss of control of chemical weapons stocks in Syria, which could have unpredictable consequences for the Syrian population and neighboring countries, as well as U.S. allies and forces in the region. The United States and other countries have assessed that the Syrian government has used chemical weapons against opposition forces in the country. […] On August 31, 2013, President Obama stated that the United States should respond with 'military action against Syrian regime targets' in response to the August 21 attack and added that he would ask Congress to grant authorization for the use of military force. The White House had previously announced on June 13, 2013, that the Syrian government had used chemical weapons 'on a small scale against the opposition multiple times in the last year.'"
CRS Report for Congress, R42848