 | This article needs additional citations for verification. (December 2009) |
| M40 field protective mask | |
|---|---|
 A soldier from the 70th Brigade Support Battalion, 210th Fires Brigade, 2nd Infantry Division wears the M40 during an NBC exercise in South Korea. | |
| Type | Gas mask |
| Place of origin | United States |
| Service history | |
| In service | 1992–Present (U.S. military, limited use after 2006) |
| Used by | See Users |
| Production history | |
| Designed | 1980s |
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 deficient environment or against ammonia.