What are the different types of gas masks?

Personal Protection Equipment (PPE) is a wide and very technical world. Civilians got a bit of a crash course in airway protection during the COVID pandemic, with many everyday folks getting their first introduction into the differences between surgical masks, N95 respirators, particle masks, and how different countries use different filter ratings (South Korea’s KF94 as one example among many). 

As world events continue to change the threat profile and risks we face, many prepared civilians are looking to increase their readiness beyond the disposable, single-use respirators that were so hard to find during the height of the pandemic. Gas masks provide enhanced, reusable protection against an even wider array of threats beyond just airborne pathogens, but there’s a bewildering array of mask types, certifications, filter types, and other details. This guide aims to clear up the confusion around airway protection PPE and provide a starting point for those looking to increase their own personal readiness levels, no matter what comes their way.

Gas masks vs respirators

Image source: MIRA Safety & Envato 

The terms “gas mask” and “respirators” are sometimes used interchangeably, which creates its own problems when trying to search or shop for your own protective needs. As defined by the Occupational Safety and Health Administration, gas masks are a type of Air-Purifying Respirator (APR) since they actively remove toxic gases from the air as it passes through a filter (sometimes called a “chemical cartridge”) and into the interior of the mask. This is a more sophisticated level of protection than Particulate Respirators like the N95 or KF94 which physically block particles above a certain size from entering the mask. In the case of N95 respirators, they block any non-oil-based particles greater than 0.3 microns in size with 95% efficiency, hence the name. That’s very effective against things like dust, bacteria, viruses, or liquid aerosols, but doesn’t protect against toxic gases, whose atoms are much smaller than the filter size. For example, a carbon monoxide atom is 112.8 picometers in size, which converts to 0.0001128 microns; way smaller than the 0.3 micron limit of an N95.

In short, gas masks are a type of respirator, but not all respirators are gas masks. Gas mask filter cartridges usually have a particle filter layer as well as the chemical protection layer in what’s called a “combination cartridge,” but not always. To keep things simple for this article, we’ll use the term “gas mask” separately from “respirators” to keep the focus on masks that protect against toxic gases.

CBRN vs Hazmat

Image source: Envato & MIRA Safety

A term that frequently pops up in the world of respiratory protection is the acronym CBRN, which stands for Chemical, Biological, Radiological, and Nuclear. It derives from the older military NBC (Nuclear, Biological, and Chemical) acronym, and expands the scope to include radioactive threats that are still dangerous but fall short of a nuclear bomb detonation.

Compared to Hazardous Materials or HAZMAT terms, CBRN is more defense-oriented and assumes that the release of a particular substance is intentional and malicious. It also implies more aggressive agents than what you’d typically find in an industrial accident or natural disaster like a wildfire. While smoke and industrial chemicals are dangerous in their own rights, chemical weapons or weaponized radiation carry additional risks that we’ll get into next.

Industrial vs “military” gas masks

Image source: Envato 

As mentioned above, the workplace can carry its own risks to health and safety. Jobs that routinely handle hazardous materials or might have to respond to an accident mandate workers use gas masks certified for their particular industry. These gas masks are often made from silicone, neoprene, thermoplastics, or rubber, and will usually come with cartridges that only filter a narrow range of chemical, medical, or other hazardous agents. Depending on the exact employer and workplace standards, they might cover the whole face or only the airway (called “half-face” respirators). The standards for industrial masks and filters will typically be set by civilian administrations like OSHA, NIOSH, or their foreign counterparts.

CBRN-rated gas masks, on the other hand, are designed for more durable and wide-ranging protection. Made from bromobutyl rubber or similar hardened materials, a CBRN gas mask is built to resist chemical weapons that are highly corrosive like Mustard Gas that eat through silicone or other less resistant materials. CBRN gas masks work best when using similarly “beefed up” CBRN filters. Since military or emergency response personnel can’t predict the kinds of airborne threats they’ll face on any given day in their industry, CBRN filters are meant to handle a wide range of threats instead of just specific agents, including oil-based aerosols that normally clog up or soak through industrial or particle filters. For example, the NBC-77 SOF filter we offer here at Mira Safety protects against a huge range of toxic agents.

Compared to industrial gas masks, CBRN-rated masks are standardized by law enforcement agencies or military branches, which is also why they’re commonly called “military” or “military-style” gas masks. Check out our other article for a more detailed description of how CBRN masks and filters are rated.

Gas mask types

With the broader design philosophies and threat types out of the way, let’s look next to the individual types of gas masks and how they’re used.

Half-face respirators

Image source: Envato

I know I said I’d avoid using the term “respirator” in this article, but there’s a good reason for the exception here. Depending on the exact model and filter cartridge, half-face designs can protect against some toxic gases, but since they don’t protect the eyes they aren’t commonly called “gas masks.” The mucous membranes around the eyes readily absorb many of the toxic or disease-causing threats in the CBRN world, so half-face masks are typically used for industrial or medical purposes. 

However, certain models are designed for tactical uses like police and emergency response. Paired with goggles, they can provide basic protection against some CBRN agents like tear gas (CS) and pepper spray (OC), plus they’re easier to carry and keep at the ready than bulkier designs.

Full-face gas mask

Image source: MIRA Safety

Full-face protection is central to how CBRN-rated masks work. Many, if not most, CBRN threats attack the eyes or can be absorbed into the bloodstream through the thin membranes around them. Additionally, some of the more serious weaponized chemicals, like blister or nerve agents, are readily absorbed through the skin.

Full-face gas masks come in models designed for industrial use instead of CBRN protection and, again, this mostly comes down to the materials they’re constructed from and overall build quality. For the best protection, full-face gas masks are designed to work with a full body suit rated for the same type of threats as the mask/filter combo itself. Mira Safety offers several CBRN-rated suits and accessories to extend protection to the entire body.

Escape hoods

An escape hood works similarly to a full-face gas mask but combines full-face protection with the head portion of a protective suit. Instead of sealing around the face, these seal around the neck, which makes them more comfortable for some users like children, but also makes them more restrictive for complex tasks that require a lot of motion like military operations or self-defense. As a result, these are built for limited-time, single-use applications like escaping from a chemical environment or burning building.

Powered Air Purifying Respirator (PAPR)

Image source: MIRA Safety

This category can describe an entire air purifying system, or a plug-and-play accessory that augments a compatible gas mask with certain benefits. Most gas masks use negative pressure to seal around the face, basically creating a vacuum that sucks the edges of the mask against the skin so the only way air can enter is through the filter. A PAPR works in the opposite way with positive pressure, actively blowing purified air into the mask so contaminated air is continually blown away from the face.

This has certain advantages since it’s less dependent on a rock-solid seal against the skin and makes it easier to breathe since filtered air is continually provided to the user instead of them having to suck air through a filter canister. The positive pressure design also makes them better for users with facial hair. However, they need a power source to generate the positive pressure air current so they require a battery which adds some bulk and weight. Thankfully, they don’t require all that much power so modern designs can have 12 hours of battery life or more.

Self-Contained Breathing Apparatus (SCBA)

Essentially a SCUBA tank on land, an SCBA doesn’t filter the air and instead provides its own pre-packaged supply. This makes an SCBA much heavier, bulkier, and time-limited than the other types we’ve already discussed, but they’re also the only type that guards against oxygen deprivation. Air is a mixture of different gases like nitrogen, oxygen, carbon dioxide, and others. The human body needs at least 19.5% oxygen in the air to survive and function. Any lower than that threshold and there’s a danger of hypoxia, which is dangerous in itself or can cause confusion and poor decision-making that increases a person’s vulnerability during an emergency.

Most CBRN threats don’t remove oxygen from the air, which is why simply filtering out the toxic elements from the atmosphere is enough to protect users in a CBRN environment. But there’s one scenario that routinely does deplete available oxygen: fire. Fire and smoke carry a significant risk of oxygen deprivation, so the main response to a fire is to leave the area as quickly as possible. However, firefighters need to operate in burn areas for extended periods to do their job, so SCBAs make sense for frontline firefighting duty. For anyone who’s not actively fighting a fire, protecting against the toxic burn products present in the smoke is the primary concern.

Surplus vs new manufacture

Image source: Envato & MIRA Safety

Since gas masks are common standard issue items in militaries across the world, there’s a large secondary market for surplus gas masks. Surplus gas masks and filters come from all over the world and vary wildly in their quality, features, and age. That also translates to lower prices than newly manufactured masks. It’s possible to find good deals on quality surplus masks, but it’s also very difficult to judge how much a mask will actually protect you without specialized training and equipment. There is no generally accepted third party procedure for certifying surplus gas masks, so there’s only the seller’s word to go by.

Gas masks are lifesaving emergency equipment, and there’s no way to know if a surplus mask will work as advertised until it’s actually deployed in a CBRN environment. It’s simply not worth saving a few bucks only to start sucking in nerve gas or mercury vapors down the road. As such, we at Mira Safety can’t recommend using surplus masks for anything more than costumes and movie sets. It’s why we only offer newly-manufactured masks, filters, and accessories that we know will perform as designed. That might mean a price difference compared to the surplus market, but we believe that consistency, safety, and peace-of-mind can fit into any budget.

Conclusion

These are the primary categories of gas masks that you’ll find out there, but this only scratches the surface. Individual models have their own features and use cases so it’s important to research your own needs, risks, and personal considerations. That’s why we put together this article to give a broad, high-level overview of the gas mask market to arm you with the basics for a good starting level of knowledge.

For an even more detailed breakdown of what to look for in a particular mask, check out our most recent buyer’s guide, which also covers recommendations for specific features and needs.