The Ultimate Gas Mask User Guide

by Tommy Grant

This post has been updated from our original Gas Mask Guide which was first published in 2018. We keep our content updated as the world around us changes and as we learn new skills and techniques.

Gas masks may seem stereotypical for prepping but they are an important piece of protective equipment for a variety of situations. Sticklers may insist on calling them ‘protective masks’ since they can protect you from more than just gas. A gas mask has already saved my life against chemical weapons and biological threats. It gives a fighting chance against some radiation exposure as well.

I taught classes on gas masks to thousands of military personnel for several years. I have even worn one while exposed to live chemical warfare agents and can assure you that masks work. This gas mask guide will provide you with the confidence to select and maintain masks perfect for you and your family.

Contents (Jump to a Section)

Types of Gas Masks

Gas masks have been around for a while, and there are many different types. Many countries work independently to develop their own masks. Up until recently, even our armed forces branches worked separately to develop their gas masks. As a CBRN technician who oversaw the operation of training gas chambers and base-wide training exercises over the course of my service, I encountered many types of masks. Some of the most notable types of masks that you may encounter include:

  • US Military M17 Protective Mask – This is the mask that was a standard issue during the Vietnam War for all US Military components. One major flaw with the mask was the need to remove the mask to swap filters.
  • US Military M40 Protective Mask – This mask has distinctive lenses for each eye and is one of the heavier options. It serviced the US Army and Marine Corps. It was replaced at the beginning of the century by the M50 mask. It uses 40mm NATO C2 charcoal canister filters.
  • US Military MCU-2A/P Protective Mask – This was the mask of choice for the Navy and Air Force for a lengthy period. Whether the mask is an A or P variant doesn’t change much- it designates whether the mask is set up for aircrew or not. The mask replaced the M17 mask and was replaced by the M50 mask. It had problems handling blister agent chemical weapons, and some were even issued with a ‘second skin’ as an additional barrier. They use 40mm NATO C2 charcoal canisters. We have a full review of the MCU-2P here.
  • US Military M50 Protective Mask – This is the current mask servicing all components of the US military. The M50 was developed cooperatively by all branches to meet the need of having a balanced tough mask that does not interfere with firearm operation or block the field of view.
  • Israeli 4A Military/Civilian Gas Mask – These masks are often available on the secondary market since the Israeli Defense Force (IDF) issued them to all Israeli citizens. It uses 40mm NATO canisters which are also relatively easy to find on the second-hand market.
  • MSA Firehawk Full Face Respirator – This is a standard-issue mask for many firefighters as part of an SCBA setup. It also has a CBRN attachment using a charcoal filter with a long hose. This hose helps with breathing in smoky environments since the filter can be lower on the body and smoke rises.
  • MIRA CM-6M – This mask is made for civilians but has the durability and materials of masks typically made for militaries (bromobutyl rubber, etc).
  • 3M 6800 Full Face Respirator – This versatile civilian mask is used by fire departments, hazmat teams, and laboratory personnel. There are a variety of filters widely available, as well as powered air-purifying respirators (PAPR) and supplied air setups (SCBA).

My Experience with Different Masks

I have traveled the globe teaching people how to use various types of gas masks along with other disaster-related training. I have plenty of experience using the MCU-2P, M50, Firehawk, and the 6800 in environments that were life-threatening. I’ve also had my hands on the Israeli mask, M40, M17, Land Warrior, Czech M10, Dragr PAPR 4500, Soviet GP-5, and even some relic masks from WWI.

I know how a solid mask with a good fit can save your life from direct experience. Sometimes the little things about the mask make the biggest difference. The gas mask field of view and how easy the filters are to breathe through can make accomplishing tasks a world of difference. Switching my classes from the MCU-2P to the M50 made a world of difference in the number of heat exhaustion incidents we had in the desert. A drinking tube attachment on the military masks helped with this too.

7 Fast Gas Mask Facts

  1. You can never have enough spare filters.
  2. You can improve the time it takes to put on your mask by 300% with practice.
  3. Gas masks are hot, sweaty, and uncomfortable for long periods.
  4. Gas masks protect from a wide range of respiratory risks associated with many types of attacks, accidents, and disasters.
  5. A gas mask does not ‘fix’ exposure- put the mask on before you are exposed as quickly as possible!
  6. Beards do not cooperate with gas masks and can cause leaks.
  7. Surplus gas masks were decommissioned for a reason. They may not protect you when it really matters.

Gas Mask Rating Types

There is some misinformation out there as to what actually counts as a gas mask. “Gas mask” is just a term for a full-face respirator equipped to handle chemical gas hazards. There are full and half-face respirators that only handle particulates, but the full-face masks with the correct filters are considered gas masks. Just like there are many models of gas masks developed over the years, there are also several ratings for both masks and filters. Ranging from MILSPEC to NIOSH/OSHA requirements, these ratings can let you know what kind of protection you can expect from a mask. If a mask does not meet any standard or requirement, you should probably look elsewhere. If a mask or filter doesn’t have a rating, it could be a prop mask, costume mask, or even for airsoft. Make sure you have a real mask and filter with a real rating. Mask filters can have many ratings but here are the important ones for survival and prepping purposes:

  1. NBC rating: The filter is verified and rated to withstand Nuclear, Biological, and Chemical threats for at least an 8-hour period.
  2. CBA/RCA rating: The filter is verified and rated to withstand Chemical Blowing and Riot Control Agents for at least an 8-hour period.
  3. Specialty ratings: There are other ratings where a filter can be rated to protect from a specific NBC or HAZMAT threat.

Mask ratings are complex but can be broken down by who approved them:

  1. NIOSH rating: NIOSH gives us the widely known rating of N95, which can be found on the small cloth masks used extensively in the medical field and other applications. Most gas masks fit the N95 rating, which simply means they filter out 95% of airborne particles. The rating is good for the elastic band mouth covering but does not mean much if you are looking for complete protection. The NIOSH ratings can be more easily understood with a table:
Rating Letter Class Rating Number Class
N – Not oil resistant 95 – Removes 95% of all particles
R – Resistant to oil 99 – Removes 99% of all particles
P – Oil-Proof 100 – Removes 99.97% of all particles (HEPA)

These letters and numbers combine to give the rating, so P100 is one of the best ratings NIOSH gives respirators. This shows that an N95 mask is better than nothing, but definitely not the best solution in life-or-death situations.

  1. MIL-SPEC rating: The main MIL-SPEC rating associated with gas masks is the PRF-EA-10003 rating. This encompasses the NBC and CBRN protection factor combined with how the mask withstands abuse in the field. It is an aggressive rating that only one mask has achieved: the M50 JSGPM (Joint Service General Purpose Mask).

As you can see, masks themselves are rated to MIL-SPEC or NIOSH penetration standards, but filters are rated to the actual threat. Plenty of people say “This mask is NBC-rated”, which is a misconception because the filters are actually rated and the mask is NIOSH and possibly MIL-SPEC rated.

Where to Buy a Gas Mask

There are a few options when it comes to buying a gas mask:

Online – You can find almost anything online these days, including all of our top gas mask picks. Getting a second-hand mask online can be risky since you cannot inspect the mask beforehand for disbanding or any other red flag that may indicate the mask is past its service life, especially if the masks are prone to issues over time. New masks are a good option online as long as you recognize the mask. Novelty masks and prop masks are available, so make sure you know which model and how effective the mask truly is.

Industrial Supply – Industrial supply stores often sell respirators with filters that go beyond the capability of military masks. The downside is that they are not designed to withstand the same abuse as military masks. A 3M 6800 or related mask can set you back a few hundred dollars from an industrial supply store- so they are not the cheapest option either.

Military Surplus – This option can be risky. Masks have become much better over time and older masks can show signs of degradation. Also, filters may be harder to get a hold of. If the mask is not second-hand, and filters are readily available, then a quality military gas mask from a surplus store is a good find.

This video does a great job at breaking down potential issues of getting a gas mask from a surplus supplier:

Our Suggested Gas Masks

I have personally tried almost all of the military-issued CBRN masks and trained thousands on many various types around the world. When people are just getting started out, the one I always go back to is from my days as a HAZMAT responder- the 3M 6800. This mask is so lightweight and versatile but it still has great functionality. It is easy to breathe through (without fogging) and does not have the pinch-point problems some older masks have.

It received the highest rating from NIOSH and meets ANSI Z87.1-2003 impact requirements making it durable both on and off your face. The filters and accessories are widely available and easy to find. There is also great component support through 3M and other vendors if you need to replace or change out parts of the mask- or just get spare parts in general.

One of the most important parts is that the mask does not break the bank, and it actually comes in as our budget pick in our full comparison review for the best gas masks available. We talk about the downsides in our full review, like how it can’t handle certain chemical warfare agents.

3M 6800

An industrial option that will keep you protected when paired with the right filters.

Where to Buy

$121* at Amazon

*at time of reviewing

Avon M50

The preferred choice for the US Military, longer protection, and a comfortable seal make this the mask to beat.

Where to Buy

$349* at eBay

*at time of reviewing

How to Make Sure a Gas Mask Fits

Unlike a hat or clothing, medium-sized gas masks usually fit a wide range of people. Masks need to fit your face, and your head size does not matter as much since straps are usually adjustable. Small children and those with smaller faces will need a small mask or a specially developed infant mask. Large masks are rare but are needed by a few with very large faces. A staggering 90% of adults will fit in a medium gas mask. Even if you have a mask that is the proper size does not mean it fits. Proper fitting ensures that the mask has created a seal with your skin and that your breathing is creating positive pressure within the mask. Here are the easy-to-follow steps to make sure you have a good fit:

  1. Loosen the mask straps completely and pull them over the front of the mask and out of the way.
  2. Roll the mask on, planting your chin firmly in the chin cup first and then seating the nose cup in place.
  3. Hold the mask in place while you pull the straps over the back of your head.
  4. Tighten the straps. If there are multiple straps, tighten the middle first, then the top, and then the bottom straps last.
  5. Check the seal of the mask by covering the filters with your hands and inhaling sharply. The mask should pull in slightly and not allow any air in. If it does not, re-fit your mask by following steps 1-4 again.
  6. Remove the mask by only loosening the bottom straps and pulling the chin cup out and over your face.
  7. Store the mask with straps over the front for rapid access. Store the mask with straps inside the mask for longer periods to prevent the straps from stretching and wearing out.

A few reasons a mask may not fit is due to the sizing. The full-face mask may have different sizing options, as well as the nose cup. Some variants, like the M50 or 6800 offer a variety of nose-cup and facemask combinations to ensure the best comfort in the mask.

Banana oil/isoamyl acetate is often used by professionals to ensure a good fit. You can grab some ampules for very cheap online that are great for breaking open with your mask on. If you can smell it, then you have a gas mask fit issue- pretty straightforward.

Guys should note that beards do not cooperate well with gas masks getting a good seal. A hygiene kit with shaving equipment can come in handy in the event of a pandemic or CBRN situation. Trust us, we’ve looked into beards vs gas masks zealously and beards are best dealt with just shaven off.

Poor vision can also be problematic with gas masks. To deal with this you can source gas mask inserts, which are glasses meant to snap into place inside of a gas mask. Those in the military and in jobs that require masks are often issued inserts. If you don’t have access to an optometrist who can source inserts for your gas mask, some clever preppers have used old glasses, removed the glasses’ arms, and secured them to the mask lens with duct tape for a temporary solution. You cannot use glasses with the arms on them or they will disrupt the seal where the arms go through the mask.

Scenarios to Use a Gas Mask

A few acronyms that are commonly used that show where a gas mask may be needed include:

  • NBC – Nuclear, Biological, Chemical
  • CBRN – Chemical, Biological, Radiological, and Nuclear

These describe events or attacks (NBC is the older term, and CBRN is the newer) where a gas mask and other specialized personal protective equipment especially come in handy.

Masks also come in handy when you are dealing with falling ash (volcanoes, fires), high pollution, riot agents (tear gas, pepper spray), and even around the house (mold, paint, etc).

An approved and functional gas mask provides protection from all of the scenarios above in most situations where they would occur. Protecting your airway is a priority in each of these since they are most susceptible to exposure. It is important to put on your own mask before assisting others. Otherwise, you could be quickly incapacitated and unable to help anyone.

Survival Kits that Need Gas Masks

You can include a gas mask in almost any survival kit. Some survival kits make a whole lot more sense than others, though. A simple N95 mask may be acceptable to include in a lightweight GHB (Get Home Bag) or BOB (Bug Out Bag). A gas mask really excels in Specialized Kits, however. Here are some specialized kits that really should include a gas mask for each member of your family:

If you require one of these kits based on threats in your area, then you should include a gas mask in them. You can learn more about identifying threats in our TrueRisk section, which breaks down risk as simply probability and impact for possible scenarios and rates them with a TrueRisk score. Additional kits that could include a gas mask, but are not necessarily standard are:

Gas masks are usually not practical for Everyday Carry (EDC) use due to their size, weight, and public perception. A hygiene kit with shaving equipment is a good idea to keep close to a mask since beards can prevent a gas mask from sealing, making them useless.

Troubleshooting, Maintaining, and Inspecting Gas Masks

Most gas masks are tough, but there are some problems that could occur if they are not cared for properly. The rubber and silicon can disband from the facemask. Straps can dry rot; metal components can rust and degrade. Masks can deform if stored improperly. Many older masks and military surplus have issues with yellowing lenses. The point is that gas masks are not fail-proof, and you have to take care of them to keep them in life-saving condition. This is one of the reasons why new masks are the way to go when buying a gas mask.

Troubleshooting a gas mask is relatively easy. If a mask is difficult to breathe through, replace the filter and see if it improves. If it does not, you should look at the inlet valve behind the filter(s) to determine if there is debris or a problem in the operation. If positive pressure from exhaling is causing your mask to ‘unseat’ you may have an issue with your outlet valve.  If you are having a problem with the mask having or keeping a seal, you should follow or mask fit instructions above. If these steps do not fix the problem, inspect the mask for disbonding described below.

Maintaining a gas mask is easy too. Keep your mask debris-free and wash it after use, even if it is not contaminated. Use a warm soapy water solution to wash the mask after removing the filters and head harness. Do not use bleach or alcohol wipes since they will yellow mask lenses and damage silicon and bonding material.

Inspecting a gas mask can save your life. Gas masks aren’t bulletproof as far as problems go, and sometimes they can be hidden. Run your finger along each bonded seam in your mask looking for signs of separation. Inspect filter attachment areas for cross-threading if applicable. If your mask has metal components, look for signs of rust or corrosion. If you run across any of these red flags, the mask should be cut across the face shield and discarded as unusable.

Additional Gear Needed With a Gas Mask

A gas mask is great for protecting your face and your respiratory tract, but what about the rest of your body, your home, and even your equipment?

A mask should be supplemented with key supplies and accessories to complete the protective outfit. You should include:

Drawbacks of Gas Masks

Gas masks are not the easy cure-all for everything that could happen. There are plenty of situations where a gas mask cannot help. Here is a quick list to keep in mind as you get your mask ready for your survival kit:

  • A standard gas mask cannot supply oxygen in an oxygen-depleted environment.
  • They are not meant as a protective covering for ballistics or debris.
  • Masks can provide a false sense of security if worn improperly or if you have the wrong type.
  • Gas masks can increase the chance of heat exhaustion.
  • You cannot eat or drink in a gas mask (unless it is equipped with a drinking tube and adapter).
  • Some masks limit your vision.
  • Some masks are more difficult to breathe through, making physical activity difficult.
  • If you have a beard, a gas mask will not seal correctly.

If you keep these drawbacks in mind, gas masks are still useful and can save your life. It is better to be prepared and not need a gas mask than to need one and not have one. South Koreans even have gas masks postured for rapid access in their subway system:

The Final Word

I hope that by now you feel like an expert on anything and everything gas mask related. It felt like a trip down memory lane getting this information together since I have taught thousands about the benefits, use, and upkeep of gas masks. Just getting a mask is not enough- you need to know how to use it, keep it in good condition, and its limitations. If you are looking to learn more, check out a few related posts:

With this guide, we hope we have helped you get to that point. Don’t keep it just stashed away in your specialized kit or survival kit– get it out, keep it maintained, and know how to use it!

Keep exploring, stay prepared, and be safe.

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