(HRW) – International efforts to deter chemical attacks in Syria in the year since the devastating sarin attack on Khan Sheikhoun on April 4, 2017, have been ineffective, Human Rights Watch said today. Human Rights Watch has collated and analyzed evidence of chemical weapons attacks in Syria between August 21, 2013, the day of the deadliest chemical weapon attack in Syria to date, and February 25, 2018, when the Syrian government used chlorine in the besieged enclave of Eastern Ghouta.