Lewisite
People exposed to the toxic chemical lewisite should immediate call emergency services.
They should also take measures to prevent other people from being exposed to it.
Lewisite is a a chemical compound that was developed by the United States to be used for chemical warfare during the first World War but was never used for that war. Lewisite is a blistering agent and lung irritant. It belongs to the same family as arsenic and, like arsenic, is poisonous. The chemical has a pleasant geranium-like smell and is colourless when in pure form. When mixed with other chemicals lewisite appears brownish or blackish in colour.
See also