Symptoms of a sarin attack often include loss of voluntary muscle control, an inability to breathe, drooling or foaming at the mouth, nausea, and vomiting, and “pinpointing” of the pupils, says John Gilbert, a senior science fellow with the Center for Arms Control and Nonproliferation. “Several Khan Sheikhun victims also exhibited what can be described as ‘claw hands,’ where a victim’s hands contract in a claw-like posture, often with the hand bent forward at the wrist,” he says.
Sarin is liquid at a moderate temperature and pressure but vaporizes very quickly (in seconds to minutes) once it’s exposed to air, Gilbert says. Once it’s released, sarin dissipates quickly but is heavier than air, which means, “It would stay close to the ground or even descend into low places such as basements or bomb shelters,” Gilbert says. If sarin is released, people who die often have no external injuries such as shrapnel wounds or burns. “There may also be dead birds or animals near the site of a sarin release and those animals would also not show external wounds,” he says.