Page "Gas mask" Paragraph 31

The forerunner to the modern gas mask was invented in 1847 by Lewis Haslett, a device that contained elements that allowed breathing through a nose and mouthpiece, inhalation of air through a bulb-shaped filter, and a vent to exhale air back into the atmosphere.

According to First Facts, it states that the " gas mask resembling the modern type was patented by Lewis Phectic Haslett of Louisville, Kentucky who received a patent on June 12, 1849.