How many people died from poison gas during world war 1?

During World War I, it is estimated that around 1.3 million soldiers were affected by poison gas, with approximately 90,000 of those fatalities attributed directly to gas attacks. Poison gas, used extensively on the battlefields, included deadly agents like chlorine, phosgene, and mustard gas. While the immediate death toll from gas was significant, many survivors suffered long-term health effects.