The development of the gas masks cannot be associated with anyone's name but can be traced back to early 1915 when modern-day chemical warfare weapons started coming into play. However, the theory on which this particular device was structured can be further traced back to 1819 when the concepts of the modern-day defense respirators had already been evolving.
Augustus Siebe had found the helmet, with an air pump and tube structure. The crude devices again evolved into the discovery of 'Inhaler or lung protector'. Lewis Haslett patented this device in 1849. It is an air-purifying respirator, which helps filter dust and ash particles from the air, before inhalation. If we talk about modern gas masks, they are somewhat upgraded and improved additions to the older designs. One can check out a wide selection of high quality gas masks for sale on https://www.gasmaskpro.com/
Regulateur was a new design, which was based on the same concept but was invented by Auguste Denayrouse and Benoit Reouquayrol. This was developed to help rescuers reach into deep mines and save trapped miners.
The development of the gas mask in 1914 was courtesy of Garrett Morgan whose developments on the device helped save 32 lives of people trapped in an underground tunnel over 250 feet below Lake Erie. He patented his device as the Morgan Safety Hood and smoke protector.