The MCU-2/P is the standard protective mask for the United States Air Force and Navy. First fielded in the early 1970s, the mask featured a one-piece silicone lens, drinking tube, voice diaphragm, and a secondary voice diaphragm which could be swapped to the other side depending on the user's shooting preference.

The MCU series protective masks were influenced by the XM-29 and XM-30 prototype masks. These experimental masks were born in the search for a lighter, more mobile mask that could be used by left and right-handed shooters and have the ability to be
MCU 2P Poster

MCU-2/P (Scott) original ad poster. Photo courtesy of Gas Masks Collector's Community (Facebook).

compatible with optics. With these requests, the designers at ILC Dover presented the XM-29 and XM-30 prototypes to the United States Armed Forces. The Air Force and Navy accepted the design and fielded the first MCU-series masks in the early 1970s while the Army and Marine Corps rejected the design and later fielded the M40 Field Protective Mask.

Initially, the MCU-2/P was made both by MSA and Scott Safety. Scott eventually stopped manufacturing the MCU-2/P while MSA continued to be the sole producer for the US government during the 90s. The limited quantity of MCU-2/P gas masks made by Scott Safety all used a silicone facemask and a clear silicon visor. These masks are dated anywhere around early to late 80s and are extremely rare which makes them a valued item among gas mask collectors. MSA continued to manufacture the MCU series masks and the MCU-2A/P followed by the 2nd Generation MCU-2/P, which uses a polyurethane visor instead of a silicon visor. This became the standard-issue until the arrival of the MSA Millennium (post-2002), and eventually, the Avon M50.


US Navy MCU2/P Medium Gas Mask with Scott 40mm P100 Filter and Clear Polycarbonate Protective Outsert. This MSA mask is dated 2002 and the exhale valve cover is dated 2003.

MCU2p with Scott P100

Side View of the MCU2/P gas mask with Scott P100 Filter

XM-30 Gas Mask

A picture of the XM-29 prototype gas mask.

MCU-2A/P Edit

The MCU-2A/P variant featured an internal M101/AIC microphone that connected to a female jack which was used with the U-137/U type male audio plugs. This style of voice emitter was used on many masks produced by the United States such as the XM-44 and M42.

With the MCU-2A/P Gas Mask, an internal microphone could be placed inside the mask and connected to an external communications system through the connector on the front voice emitter. However, field experience and testing in the late 1990s showed that the microphone connector assembly represented a damage failure point on an unacceptable number of MCU-2A/P masks. Since changes in technology provided external mask communications capabilities that no longer required a connector assembly, it was decided to discontinue the MCU-2A/P. All further production reverted to MCU-2/P masks.

Design and Accessories Edit

The MCU facepiece was made grey silicone rubber (Early MCUs made by Scott used a yellowish-tan silicone) with the lens made of clear silicone. Silicone rubber has an upside and a downside; the upside is that it is flexible and has impermeable properties, the downside is that Silicone rubber starts to deteriorate when exposed to blister agents or compounds containing Hydrogen nitride. Today, MCU series masks are usually found with yellowed lenses due to the degradation of silicone rubber over time. The oral-nasal cup and outlet valve cover were made of a black silicone rubber and the voice diaphragms were made of black-painted Aluminum. The MCU series masks also come with a specially designed chemical hood made of Butyl rubber. Butyl rubber is favoured because of its impermeable properties and the fact that it does not tear like other impermeable rubbers (An example would be Perfluorocarbon rubbers, which are extremely impermeable but have a tendency to tear easily.)

The MCU-2P and MCU-2A/P are issued with a C2 or C2A1 filter canister, a chemical hood, and a carrying bag. Other accessories include clear and tinted outserts, a specially-made hose for connecting to a blower unit, and an HGU-65 hood for use with Toxicological Agent Protective gear. The outserts mount on the mask via a fixed rubber string which loops around the mask voice emitter and clasps which grab the top of the soft lens. The outserts are very stable once mounted and provide significant protection against small blast fragments, scratching and impacts.

As with most modern military masks, it is possible to aim a rifle while wearing the MCU-2/P. This will cause the outsets (if used) to rest against the stock and maybe even contact the rear sight post. Using the iron sights, the user will simply have to tilt their head slightly more compared to a normal maskless cheek rest to align the dominant eye with the iron sights. It will require some force to push the cheek against the stock to align the eye with the sights but it is possible. It is, however, recommended that a parallax-free optic (dot sight or scope) be used when aiming with a gas mask as this eliminates the need to push the cheek against the stock to achieve a good sight picture with iron sights. Cheek riser usage on the stock while wearing a gas mask can make iron sight aiming more difficult.

The gas mask bag used by the MCU-2P initially was the traditional M17 green canvas bag. After the introduction of MOLLE system, changing requirements of the US Government meant the bag was eventually changed into the Drop Leg Infinity Tactical Gas Mask Pouch and the Blackhawk Omega Gas Mask Pouch. 2nd Generation MCU-2Ps and MSA Millennium masks all came with this new bag which is black in colour.


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