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Protect Yourself from Chemical/Biological Contamination Using Your Assigned Protective Mask

Protect yourself from chemical or biological contamination using your assigned protective mask. Don, clear, and check your mask within 9 seconds.

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Protect Yourself from Chemical/Biological Contamination Using Your Assigned Protective Mask



You are given your assigned protective mask with hood and carrier, a canteen with an M1 canteen cap, an M291 skin decontamination kit, an M295 decontamination kit, M8 detector paper, and applicable technical manuals (TMs). You find yourself in one of the following situations:


You hear or see a chemical or biological (CB) attack.

You realize, through other means, that you are under a CB attack.

You are ordered to mask.

You must enter a contaminated area.

After having donned your protective mask, you need to drink from your canteen.


Protect yourself from chemical or biological contamination using your assigned protective mask. Don, clear, and check your mask within 9 seconds. Drink water through your protective mask from your canteen without becoming a casualty.

Performance Steps

1. Don the mask as quickly as possible.

a. Stop breathing and close your eyes.

b. Remove your helmet.

(1) If you have the M17-, M24-, M25-, M40-, M43-, or M45-series protective mask, put your helmet between your legs (above your knees) or hold your rifle between your legs and place your helmet on the muzzle. If you drop your helmet, continue to mask.

(2) If you have the M42-series protective mask, remove your helmet and place it in a convenient location. Avoid placing it on a contaminated surface if possible.

Performance Steps Cont.

WARNING: Do not wear contact lenses with the protective mask. Remove contact lenses when the use of chemical agents is imminent

Take off your glasses if applicable.

Open the mask carrier with one hand.

Performance Steps Cont.

Grasp the mask assembly with your other hand, and remove it from the carrier.

Put your chin in the chin pocket, and press the facepiece snugly against your face.

Note. The temple and forehead straps have already been adjusted during fitting.

Performance Steps Cont.

Grasp the tab and pull the head harness over your head. Ensure that your ears are between the temple straps and the cheek straps. Ensure that the head harness is pulled far enough over so the forehead straps are tight.

Use one hand to tighten the cheek straps, one at a time, while holding the head pad centered on the back of your head with the other hand. Ensure that the straps lay flat against your head.

Performance Steps Cont.

2. Clear the mask.

a. Seal the outlet valve by pushing in on the center of the outlet valve cover with one hand.

b. Blow out hard to ensure that any contaminated air is forced out around the edges of the facepiece.

Performance Steps Cont.

Check the mask.

a. Cover the inlet port of the filter canister (M40- and M45-series) or the inlet port of the armor quick disconnect (M42-series) with the palm of your hand, and breathe in.

b. Ensure that the facepiece collapses against your face and remains so while you hold your breath (indicates that the mask is airtight).

c. Remove any hair, clothing, or other matter between your face and the mask if the facepiece does not collapse to your face.

d. Notify your nuclear, biological, and chemical (NBC) noncommissioned officer (NCO) in charge if it still does not collapse.

Performance Steps Cont.

Complete steps 1 through 3 within 9 seconds.

Resume breathing.

Note. There are no time standards for donning the hood.

Secure the mask hood.

CAUTION: Be careful when pulling on the hood, because it could snag on the buckles of the head harness and tear.

Performance Steps Cont.

If you have the M40-series protective mask, don the hood so it lies smoothly on your head.

For masks equipped with the regular hood-

Grasp the back edge of the hood skirt.

Pull the hood completely over your head so it covers the back of your head, neck, and shoulders.

Zip the front of the hood closed by pulling the zipper slider downward.

Tighten the drawcord.

Secure the underarm straps by fastening and adjusting them.

Put on your helmet.

Performance Steps Cont.

(2) For masks equipped with the quick-doff hood-

(a) Place your hands inside the hood, and expand the elastic gathering around the neck of the hood.

(b) Stretch and carefully pull the hood over your head so the hood covers your head, neck, and shoulders.

(c) Fasten and adjust the underarm straps.

(d) Put on the helmet.

Performance Steps Cont.

(e) Close your mask carrier.

(f) Continue your mission.

WARNING: Do not connect the quick-disconnect coupling half to your canteen until all surfaces are free of contamination. Chemical contamination could enter your mouth, resulting in you becoming a casualty.

Do not break the mask seal while drinking from the canteen.

Drink water while wearing the mask.

(Does not apply to M17- or M24-series masks.)

a. Press in on the top of the outlet valve cover until the internal drink tube can be grasped between your teeth.

b. Steady the mask assembly, and pull the quick-disconnect coupling out of the outlet valve cover.

c. Flip open the cover on the M1 canteen cap.

d. Push the quick-disconnect coupling into the canteen cap so that the pin enters the quick-disconnect coupling.

Drink water while wearing the mask cont.

WARNING: If resistance is not felt, your drinking system is leaking. Do not drink. Replace your canteen. If resistance is still not felt, notify your NBC noncommissioned officer (NCO).

e. Blow to create positive pressure. You should feel some resistance.

Note. Do not tilt your head back while drinking.

f. Raise the canteen upside down, and drink if the system does not leak.

Drink water while wearing the mask cont.

g. Stop drinking after several swallows, and lower the canteen. Blow into the internal drink tube to prevent the canteen from collapsing. Repeat the drinking procedure as required.

h. Disconnect the drinking system according to the appropriate TM.

8. Remove and store the mask according to the appropriate TM.

9. Perform all steps in sequence without becoming a casualty.


FM 3-3

FM 3-4

TM 3-4240-279-10

TM 3-4240-280-10

TM 3-4240-346-10

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