On April 4, 2017, an attack with chemical weapons struck Khan Sheikhoun, a town in northwestern Syria, killing at least 89 people. While the death toll likely makes this the deadliest chemical attack since an attack killed hundreds in two Damascus suburbs in August 2013, the Khan Sheikhoun attack is just one of the Syrian government’s many recent chemical attacks. Since late 2016, the Syrian government’s use of chemical weapons has become more widespread and systematic, and Human Rights Watch research shows that many of the attacks appear to be directed against the civilian population.