In its last days, the Obama Administration imposed sanctions on Syrian military officials in response to reports that President Bashar al-Assad’s regime used industrial chlorine as a weapon against its own people in 2014 and 2015. The Treasury Department on Jan. 12 announced it is freezing any U.S. assets of 18 individuals, including military personnel tied to chlorine gas attacks in Aleppo and other locations in Syria. The action marked the first time the U.S. has sanctioned specific officials in connection with Damascus’s violation of the Chemical Weapons Convention and a U.N. Security Council resolution. “The Syrian regime’s use of chemical weapons against its own people is a heinous act that violates the long-standing global norm against the production and use of chemical weapons,” says Adam J. Szubin, acting Treasury undersecretary for terrorism and financial intelligence. A U.N. investigation confirmed that Syria’s military used chlorine barrel bombs on civilians in three separate attacks. Chlorine’s use as a weapon is banned under the Chemical Weapons Convention, which Syria joined in 2013. Syria has denied its forces have used chemical weapons.