article_snippet.sent: It is a new element in warfare.
article_snippet.sent: In 1925, 16 of the world's major nations signed the Geneva Protocol, thereby pledging never to use gas in warfare again.
article_snippet.sent: But it has continued to be used, even 100 years after the first attack.
article_snippet.sent: Seven years after signing the Geneva Protocol, Italy dropped mustard gas in bombs during the invasion of Ethiopia.
article_snippet.sent: Troops sprayed the invasion of Ethiopia from planes and spread the invasion of Ethiopia in powdered form on the ground.
article_snippet.sent: The cross marks the field where troops faced the first use of poison .