The dog gas mask of World War I covered the dog’s entire head and consisted of eight layers of chemically treated cheesecloth. It had two cellulose eye lenses to allow the dog to see, ear pockets for the ears, space for the jaws to work, and a wide neckband with straps to tie around the neck. During the war, the Bureau of Mines and the Chemical Warfare Service conducted tests and experiments on the mask. Use by U.S. armed forces was limited. Little or no experimental work was done between the wars.
During World War II, military working dogs were used in the theaters of war. Several experimental dog protective masks were examined. The E12R8 and the E43R3 proved the most successful. The facepiece of the two masks were similar except for the filter attachment. The E12R8 used a filter mounted on the front of the mask. The E43R3 used two Navy-civilian mask canisters mounted on the sides.
Ultimately, the E43R3 was standardized as the M6 dog gas mask. This mask used a reclaimed, coated canvas duck muzzlepiece equipped with one large, glued- in, slightly bulged cellulose acetate eye lens. The M6 fitted over the face and muzzle of the dog. The outlet valve was located directly under the muzzle. It used two M12 (E40R1) filters¾one filter positioned on either side of the mask under the eye lens. A three-strap harness held the mask on the dog’s head. The M8 (E10R1) carrier stored the M6 when not in use. Thus, the mask was known as the Mask, Gas, Dog, M6-12-8. During the war 1,409 were produced.
Military working dogs were still used during the Vietnam War. The dogs needed respiratory protection, but the M6 mask was no longer useful. Dogs procured by the armed forces could not wear the M6 mask. Even if the M6 masks were the correct size and proper fit, only 32 were available and they were in poor condition. New masks were needed. This meant either procure the M6 again (which was not acceptable, because of its small size) or design, develop, test, adopt, and procure a new mask. One requirement for a new dog detection system included respiratory protection, which eliminated the stand-alone dog protective mask program. The M6 dog gas mask was declared obsolete in 1969.