Chemical warfare weapons are weapons that use toxic chemicals to cause harm or death to people, animals, and plants. Sarin (5 letters) is a nerve agent that was developed in Germany in the 1930s and is one of the most toxic chemical warfare agents. Nervegas (8 letters) is a general term for any type of chemical weapon that affects the nervous system. Poison gas (9 letters) is a type of chemical weapon that is designed to cause physical harm or death by inhalation.