View source for M40 field protective mask

{{Short description|Gas mask used by the US military}}
{{Other uses|M40 (disambiguation)}}
{{More citations needed|date=December 2009}}

{{Infobox military gear
| name               = M40 field protective mask
| image              = Alpha Distro, 70th BSB conducts CBRN training 130221-A-WV398-026.jpg
| image_size         = 
| alt                =
| caption            = A soldier from the  70th Brigade Support Battalion, 210th Fires Brigade, 2nd Infantry Division wears the M40 during an NBC exercise in South Korea.
| origin             = United States
| type               = [[Gas mask]]
<!-- Service history -->
| service            = 1992&ndash;Present (U.S. military, limited use after 2006)
| used_by            = See ''[[M40 field protective mask#Users|Users]]''
| wars               = 
<!-- Production history -->
| designer           = 
| design_date        = 1980s
| manufacturer       = 
| unit_cost          = 
| production_date    = 
| number             = 
| variants           =
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}}

The '''M40 field protective mask''' was one of various [[protective masks]] used by the [[United States Armed Forces]] and its allies to protect from field concentrations of chemical and biological agents, along with radiological fallout particles. It is not effective in an [[Oxygen deficiency|oxygen deficient environment]] or against [[ammonia]].

==History==

[[File:Defense.gov News Photo 100806-N-9564W-089 - U.S. Navy sailors assigned to Naval Mobile Construction Battalion 74 run in place in full gear during a battalion readiness exercise at Naval.jpg|right|300px|thumb|US Navy Seabees jog during an exercise with M40s worn.]]

The M40 was the result of a program in the 1980s to develop a successor to the [[M17 gas mask|M17-series]] protective masks which had been in service with the US armed forces since 1959. The M40 was to be a return to conventional protective mask design with an external side-mounted filter canister, rather than the internal cheek filters of the M17, which were awkward to change, especially in a contaminated environment. 

The M40 was phased into service with the [[United States Army|U.S. Army]] and [[United States Marine Corps|Marine Corps]] in the mid-1990s, with another new design, the [[MCU-2/P protective mask|MCU-2/P]] also replacing the older M17 in service with the [[United States Air Force|U.S. Air Force]] and [[United States Navy|Navy]]. However, both masks suffered from the inadequate protective capabilities of their face pieces, which was of a silicone rubber susceptible to corrosion from [[blister agent]]s.{{Citation needed|date=January 2011}} Thus, the masks were effectively ill-suited for protecting against much more than [[riot control agent]]s, and a [[butyl rubber]] 'second skin' had to be quickly issued for fitting over and reinforcing the M40 facepiece to make it effective in its intended role.

The M42 series masks are a variant of this mask with alterations that make it better suited for use by [[Armoured fighting vehicle|armored vehicle]] crews, who have to connect their masks to and draw air from their vehicle's own filtration system.

The M40 field protective mask is currently being replaced by the [[M50 joint service general purpose mask]].<ref name="M50">{{cite web|url=https://www.mcbhawaii.marines.mil/News/News-Article-Display/Article/539652/m50-new-look-same-protection/ |title=M50: New Look Same Protection |last=American Horse |first=LCpl Vanessa M. |date=2 December 2009 |publisher=[[United States Marine Corps]] |accessdate=22 December 2009 |url-status= |archiveurl=https://web.archive.org/web/20200626140909/https://www.mcbhawaii.marines.mil/News/News-Article-Display/Article/539652/m50-new-look-same-protection/ |archivedate=26 June 2020 }}</ref><ref>{{cite web|url=http://www.marinecorpstimes.com/news/2010/06/marine_mask_060210w/|title=Marine Corps fielding new gas mask|last=Sanborn|first=James K.|date=June 2, 2010|publisher=[[Marine Corps Times]]|accessdate=2 June 2010|url-status=dead|archiveurl=https://web.archive.org/web/20100609042627/http://marinecorpstimes.com/news/2010/06/marine_mask_060210w/|archivedate=9 June 2010}}</ref>

On September 2, 2017, the [[Philippine Marine Corps]] received 1,000 M40 gas masks and C2 filters through the [[Embassy of the United States, Manila|U.S. Embassy]]'s  Mutual Logistics Support Agreement program.<ref name="USPHL">{{Cite web|url=https://ph.usembassy.gov/us-transfers-m40-field-protective-masks-afp-support-counterterrorism-operations/|title=U.S. Transfers M40 Field Protective Masks to AFP to Support Counterterrorism Operations|date=2 September 2017}}</ref>

==Design==
The M40 field protective mask features three voicemitters, one on either the right or left side, and one in front. A voicecom adapter may be placed over the front voicemitter to amplify the user's voice. The mask can be adjusted in the field to accept the filtering canister on either side, so that a weapon may be shouldered. Right-handed shooters will normally locate the canister on the left side of the mask and vice versa.

The C2 canister on the M40 mask can protect the user from up to 15 nerve, choking, and blister agent attacks, and two [[blood agent]] attacks.

The M40 comes with a drinking system that allows the user to drink water after donning the mask for long periods of time in a chemically contaminated environment. In order to use the drinking system the user must also have suitably equipped canteen lids or an adapter for other containers.

==The prototype==
In 1983, [[ILC Dover]] came out with the first, heavily influenced by the [[M17 gas mask|M17]] mask, prototype of M40: the XM40 mask. Throughout its development it got numerous important changes that helped pave the way towards the final product, such as increased rigidity, bulk reduction and the removal of a dimple under the voice diaphragm for clearing the mask.

A year later, in 1984, the prototype was finalized as the M40 Field Protective Mask, but it did not enter service until after the [[Gulf War]]. It was mass-produced and mainstay issued from 1992 onwards.

Nowadays, XM40 models are considered extremely rare and valuable.

==Users==
<!--READ FIRST: This section is for cited entries only. Please do not add entries into this list without a citation from a reliable source. All entries without a citation will be removed. Thank you.-->

===Current===

* {{flag|Philippines}}: In service with the [[Philippine Army]] and [[Philippine Marine Corps]], supplied from the Joint U.S. Military Assistance Group.<ref>{{Cite news |date=2017-09-02 |title=US turns over 1,000 gas masks to PH military |work=[[ABS-CBN News]] |url=https://news.abs-cbn.com/news/09/02/17/us-turns-over-1000-gas-masks-to-ph-military}}</ref><ref name="USPHL"/><ref>{{Cite web|title=LOOK: Army frontliners stay COVID-19-free through decontamination|url=https://www.spin.ph/life/guide/philippine-army-decontaminating-process-fort-bonifacio-a809-20200507|access-date=2021-07-16|website=Spin.ph|language=en}}</ref>

===Former===

* {{flag|United States}}: Replaced by the [[M50 joint service general purpose mask]] in active service. Still used by [[United States Army Reserve|U.S. Army Reserve]] and [[National Guard (United States)|National]] [[Army National Guard|Guard]] [[Air National Guard|units]] and [[United States Marine Corps|USMC]] [[United States Marine Corps Reserve|Reserve]] as of 2021.<ref>[http://www.military.com/news/article/marine-corps-news/new-gas-mask-on-the-way-.html?col=1186032366495 Military.com: New Gas Mask on the Way]</ref>

==References==
{{Marine Corps}}
{{Reflist}}
{{Gas masks}}
{{commons category|M40 Field Protective Mask}}

[[Category:United States Marine Corps equipment]]
[[Category:Gas masks of the United States]]
[[Category:Military equipment introduced in the 1990s]]