During WWII many countries developed gas masks for animals. And as dogs had particular various integral roles during the war, gas masks were developed especially for them. This however, was not a new concept from the WWII, an early attempt to provide dogs with a protective mask was made in 1926 in the US, but they were rudimentary and the project was dropped the same year. In 1940, the Chemical Warfare Service asked for an improvement of those masks to use them in the war. Dogs were used during the war for patrol duty, scouting, anti-sabotage duty, message delivery and even sometimes mine detection.