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 The M9 Series Field Protective Masks are some of the most successful gas masks to be used by the United States military, derivations being adopted by at least six other countries. Starting production around 1949, the M9 Series remained in standard infantry service until the early 1960s, when it was phased out with the introduction of the M17 Field Protective Mask. 

U.S. M9 Gas Mask

U.S. Gas Mask, M9. With Carrier, C15R1 and Canister, Filter, M11.

Anti-War Protester Faces Off With National Guardsmen Wearing M9A1 Gas Masks

U.S. National Guardsmen Wearing M9A1 Gas Masks, facing off against Vietnam War protesters.

Despite being replaced by the M17 Series during the early/mid Vietnam War, the M9 gas mask continued service with National Guardsmen and Law Enforcement (even though they had specialty gas masks of their own) during protests against the war. It was also issued to Civilian Defence workers and civilians alike (there are some photos of Vietnam War protesters wearing M9 gas masks), and the M9 series would  be used by these organisations up until the 1970s. 

Even after the M9 series was phased out by general infantry, policemen and civilians alike, it continued its use by the U.S. Heavy Decontamination Crews, Chemical Stockpile Inspectors and Handlers, and EOD Personnel used the mask from its conception in the late 1940s until the early 1990s as a part of their Toxicological Agents Protective (T.A.P.) Gear ensemble.

The mask could be used with the M3 T.A.P. hood designed specifically for the M9 series. The only other chemical hood designed for the M9 series was the M4 (which looked similar to the M3 T.A.P. Hood, but was lighter in construction and did not have a second layer of rubberized material).

T.A.P. Gear During The Gulf War

U.S. Decontamination Crews wearing M9A1 Field Protective Masks with the M3 T.A.P. Hood and T.A.P. Coveralls during the Gulf War. The Man on the far right is wearing an M17A1/M17A2 Field Protective Mask with a Charcoal Impregnated Chemical Suit.

Design and Further HistoryEdit

During the Korean War, the U.S. was still using the older WWII M3-10A1-6, M3A1-10A1-6, M4-10A1-6, and M4A1-10A1-6 Lightweight Service Masks, as well as the M8-11-10 Snout Type and M5-11-7 Army Assault Gas Masks. The M9 series was based off of and intended to replace the M-5-11-7 Army Assault Gas Mask. Almost all of these masks had neoprene rubber facepieces or hoses (The M4 series sometimes had neoprene hoses), and neoprene rubber had a tendency to become very stiff in colder weather, making it difficult to open and don the mask.

U.S. Army E48 Gas Mask

U.S. Army E48 Gas Mask. This is what would become the M9 Series Gas Masks. Note the black color - M9 and M9A1 masks were made of white/gray rubber. From the collection of Bart Wilkus.

In 1948, the first prototype for the M9 was standardized as the E48 (E - Experimental, 48 - 1948). It was a whole new type of layout - it had a moulded face piece of supple black rubber, a C15 Outlet Valve mounted on the front, near the chin with rubber cement glue, tightly twisted wire, and black fabric tape. It also utilized a 60mm threaded filter inlet for the M11 filter canister, which attached to an opening on the side of the face piece. This lead to the moulded-in "moustache-type" tissot airflow deflector channels, which wrapped over the front of the centre of the face piece and ended under each of the semi-triangular eyepieces. This gave the mask a rather humorous appearance of having a large, comical-looking nose.

Inside the mask, there was an oral-nasal cup, which was improved over the types used on the M3 and M4 series lightweight masks. This was because the E48's oral-nasal cup curled in, as opposed to curling out, which gave it a better seal.

The mask used the C8 head harness, which differed from the WWII M4 and M5 head harnesses. The M4 and M5 harnesses used a triangular leather head pad which compensated for the harness's criss-cross arrangement The C8 harness, on the other hand, had a rectangular head pad made of thick, black cotton duck fabric, and the straps were arranged by creasing in half at an angle, to form two straps. The temple straps used in the C8 harness were not folded and simply went across the pad, much like the M4 and M5 harnesses.

U.S. E48 & M4-10A1-6 Gas Masks

U.S. E48 Gas Mask (left) and M3-10A1-6 (natural rubber version) Lightweight Service Mask (right). Note how the E48's C15R1 Carrier is worn at the side, it could also be worn on the chest, similar to the M7 carrier for the M5-11-7 Assault Mask. Also note the M6 Carrier Bag for the Lightweight Type Service Masks is worn on the chest here, it is usually worn on the side.

The E48 used a C15R1 Carrier, which was remarkably similar to the M7 Carrier for the M5-11-7 Assault Mask, except that the C15R1 had three "Lift the Dot" snaps on the outside and was made of olive drab cotton duck fabric which was rubberized on the inside. The M7 carrier had four simple button snaps and was made of duck canvas heavily rubberized on the inside and out, making the carrier completely watertight. 

Later on in the early 1950's, the E48 was updated and standardized as the M9 Gas Mask. It was exactly the same as the E48 in every way, except the M9 used a faceblank of soft, supple, thick white natural rubber, instead of black like the E48. Like the E48, the M9 was short-lived and not much information exists about it besides what was already said about the E48.

In 1952, the M9 was updated as the M9A1. The mask's face piece and accessories were exactly the same as the M9, but the carrier instead, was updated. It was changed from a large, bulky, waterproof C15R1 Carrier, to a small, rectangular, non-waterproof M11 Carrier. 

M9 Gas Mask

An M9 Gas Mask with M11 Drum Filter, C15R1 Carrier, and Anti-Dim Cloth.

The air-tight, vacuum-sealed tins the masks were issued in underwent a change as well - M9 tins, which were originally labelled "MASK, GAS, M9", had that marking brushed over with green paint, and were stamped over with "MASK PROTECTIVE, FIELD, M9A1".

Each M9/M9A1 came issued with an M9 face piece, with faceform tied in place, M11 Drum Canister tied to the back of the faceform, an C15R1 (M9) or M11 (M9) carrier (had the mask stuffed inside) and an Anti-Fog Cloth in its tin, usually stuck in the faceform with the M11 Filter.

Mask, Field Protective, Chemical-Biological, M9A1

An unissued M9A1 Field Protective Mask (M11 Carrier not shown in the image).


M4 Chemical Hood: A rubberized nylon hood that covers all of the mask except the lenses and the filter opening. The hood hs a olive drab nylon cord around the neck, which is threaded through a plastic plate to close the hood for a better seal. Versions of this hood were also made for the M8-11-10 Snout Type Mask and M3 and M4 Lightweight Service Masks.

MI Waterproofing Bag (issued with the M9A1 during the Vietnam War and after): A plastic bag with rubber bands inside it on a cardboard sleeve meant to seal the bag with the mask inside to waterproof it when crossing rivers and streams, for the M11 Carrier was not waterproofed like the earlier C15R1 Carrier.

Optical Inserts: A special pair of glasses with frames that loop around the inside of the lenses. Meant for soldiers with vision defects.

Optical Inserts For U.S. M2, M3, M4, M5, M8, & M9 Series Gas Masks

Optical Inserts for the M9 Series (and other older WWII U.S.) Gas Masks.

M9A1 Gas Masks With Toxicological Agent Protective (T.A.P.) Hoods And Aprons

Two men handling an artillery shell wearing the M9A1 Field Protective Mask with the M3 T.A.P. Hood and M2 T.A.P. Apron.

M3 T.A.P. Hood: Similar to the M4 Hood, but made of a thicker rubberized material with a second layer. Used for heavy decontamination and other similar tasks. 

M1 Winterization Kit: A rubberized fabric cover that helps the mask's rubber from becoming stiff in extreme cold. Covers everything but the lenses, "nose", and filter inlet and also acts as a chemical hood.

Foreign variants and usersEdit


M9A1 shown in an Italian manual.

Italy: The M9A1 was adopted and used by the Italian army.

Finland: M/61 - made of grey rubber, and manufactured by Nokia with three different models:

  • Model 1 - Most similar to the U.S. M9. The only changes were the addition of a Nokia manufacture mark on the filter side, and 'SA' (Finnish: Suomen Asevoimat "Finnish Military") replacing 'US' at the top.
  • Model 2 - This version has a longer outlet valve cover, and a peripheral seal was added. The 'SA' marking was removed, and the watchtower of the Finnish defence forces was added on the opposite side to the filter.
  • Model 3 - Final, most common model. The rubber exhalation assembly was replaced by a black plastic assembly, incorporating a voice diaphragm, the cover featuring the distinctive watchtower of the Finnish defence forces.

Sweden: Skyddsmask 51 - Similar in appearance to the M9A1, made of dark green rubber, has a similar outlet valve cover to the second model M/61. Fairly common.

Japan: Type 2 Protective Mask - A fairly distant, but somewhat similar copy of the M9/M9A1. Made of light olive drab rubber, lenses are more rounded, outlet valve is made entirely of metal. These masks are very rare outside Japan.

South Korea: KM9A1 - Made of black rubber, similar once again to the E48. Very rare, but somewhat more common than the Japanese type. Often found as specimens issued to Iraq and other forces in the Middle East - these are commonly mislabelled as 'Bulgarian' M9 copies due to the rough assumption myth started by Bart Wilkus because of the OM-10 clone produced by the same country. There is no logical evidence these are Bulgarian-made as they feature the same construction as the KM9A1, share no hardware or design patterns coexisting with period Bulgarian mask designs, and Iraq was commonly issued South Korean-produced equipment.

Vietnam War Protester Wearing An M9A1 Gas Mask Hurls A Tear Gas Canister Back At Police

A Vietnam War Protestor Wears a M9/M9A1 Gas Mask, while hurling a tear gas canister back at riot police.

Yugoslavia/Serbia: M1/M2 Series - Made of an aqua-ish green rubber, the M1 had a similar carrier bag to the M11, and was the military counterpart of the MC-1, which had no oral-nasal cup, had "MC-1" stamped on the left side of the mask in black, also had a cheaper carrier. M2: made of the same color rubber, the M2 basically was an update of the M1. It had black plastic frames instead of the green metal of the M1. A variant called the MC-2 had a drinking feature. The M2 had two different types of outlet valves - one that was a plastic cage, and one with a green deflector. A model called the M2-F was made of all black rubber and had black parts, and resembled the Finnish Nokia M/61 (third model), for it had a similar outlet vallve/voice diaphragm assembly.

Egypt: M2 - Licensed exact copy of the Yugoslavian M2.

My Toxicological Agents Protective Gear (9)

Jack Kirchner wearing his M9A1 with the M3 Toxicological Agents Protective (T.A.P.) Hood, M2 T.A.P. Apron, and Type 1 Butyl Chemical Gloves.

Iraq: Uses the KM9A1 and the Yugoslavian M1 (renamed the M-65).

Additional NotesEdit

The lower straps of the head harness system have an extra strap, which wraps around the nape of the neck, and fastens to the other side of the mask with a "Lift the Dot" snap on the end, making for a more secure fit.

The M9A1 had many strange issues and problems with the rubber, such as the white rubber had a tendency to discolor a dark olive drab green if not taken care of properly. Badly discolored M9s can be confused for the Swedish Skyddsmaske 51, or the other way around. The easiest way to tell the difference is the forehead markings - an M9 will have a "US" mark. Skyddsmaske 51s also have longer outlet valve covers.

Both the M9 and M9A1 were made in both right and left-handed models. The right-handed model has the canister on the left side of the face piece and is the most commonly found. Left-handed versions had the canister on the right side of the face piece, for they were needed less, and thus, less were made.

Right-Handed M9A1 Gas Mask With Discolored Rubber

A Left-Handed M9 (M9A1s usually have the flap on the C15 outlet valve cover warped forwards) with badly discolored rubber.

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