The Best Respirator for Abandoned Buildings (and Why a Mask Isn't One)

For dusty, moldy or asbestos era buildings, the respirator to get is a reusable half mask with P100 filters that seals to your face. The one on my list is the 3M 6200 in medium, and it’s only part of the answer. The facepiece does nothing without filters, and nothing works without a seal.

Disclosure. The 3M 6200 and the Achiou balaclava are the products I carry and link to. Those links, and the Amazon search links in the table below, earn me a commission when you buy through them. Links to manufacturers and government agencies don’t.

Entertainment, not medical or legal advice. I’m a photographer, not an industrial hygienist. A respirator filters what you breathe when it’s the right one and it fits. It doesn’t make a contaminated building safe, and nothing here is a reason to go inside one.

Is a mask the same thing as a respirator?

No. A respirator is certified by NIOSH for specific hazards. A mask is fabric. OSHA tells people who choose to wear a respirator to pick one certified for the contaminant, and NIOSH says nonapproved dust masks, bandanas and T-shirts don’t give the same protection. Of cloth masks, NIOSH says there are no standards or regulations.

The Achiou balaclava on my list is a knit tube. It’s there for cold and for not getting recognized. It does nothing for dust, spores or fibers, and I don’t count it as protection against any of them.

Even certified gear depends on how it’s worn. NIOSH says certification is no guarantee the mask will perform well as worn, and cites one study where disposable respirators cut dust by an average of only 67 percent.

Which filter do you need for mold and asbestos?

P100. NIOSH’s filter code has two parts. The letter is oil resistance (N, R or P) and the number is efficiency, where 100 means at least 99.97 percent of airborne particles. OSHA defines a HEPA filter with that same 99.97 percent figure and names N100, R100 and P100 as the equivalents.

For mold, CDC says to wear an N95 or something more protective in a building with mold damage, and a half face or full face respirator for heavy work like tearing out moldy drywall. It also wants goggles with complete eye protection, since vented ones won’t stop dust and small particles. A half mask doesn’t cover your eyes, and 3M’s data sheet says half facepieces need appropriate eye protection.

For asbestos, the filter has to be that 99.97 percent kind and the respirator can’t be a disposable. OSHA’s asbestos rule says employers must not use filtering facepiece respirators against asbestos fibers, and EPA says not to use single use paper dust masks. EPA’s accepted option is a half or full facepiece respirator with replaceable high efficiency filters, which is what a 6200 with P100 filters is.

Now the part nobody likes. NIOSH’s pocket guide treats asbestos as a potential occupational carcinogen. For any detectable concentration it lists a positive pressure self contained or supplied air respirator, and a P100 air purifying respirator appears only as an escape option. EPA says you can’t tell whether a material contains asbestos by looking at it and to leave doubtful material alone. So a P100 half mask is what you wear for the dust you can’t avoid. It isn’t permission to disturb anything. The longer versions are in asbestos in abandoned buildings and black mold in abandoned buildings.

The part numbers confuse people. 3M’s 2091 is a plain P100 filter, and the 2097 is a P100 with nuisance level organic vapor relief. Cartridges are the gas and vapor kind, like the 60921, a P100 combined with organic vapor protection. The 2097’s relief only covers concentrations below the OSHA limit, so it takes the edge off a smell and does nothing for a hazardous vapor. 3M’s page doesn’t name mold or asbestos for either one. It says the filters can help reduce exposure to “certain airborne biological particles,” which is as close as it gets. Search for the 2091 or the 2097 on Amazon.

Filters catch particles. NIOSH says respirators like these only filter out particles, that toxic gases need a cartridge type respirator, and that oxygen deficient air needs supplied air. OSHA treats any atmosphere under 19.5 percent oxygen as immediately dangerous, and 3M’s sheets say its half masks are not for dangerous or oxygen deficient environments. Stale, closed up air is a separate problem and has its own post, what is dead air.

Why does the seal matter more than the brand?

A respirator only cleans the air that goes through the filters. What leaks around the edge goes straight in. 3M’s page promises protection up to 10 times the OSHA limit only when the 6200 is properly fitted, and NIOSH says that without fit testing you can’t know how well a respirator fits. The fallback it gives is a user seal check every time you put one on.

Facial hair is the usual way a seal fails. OSHA bars employers from allowing tight fitting facepieces on workers with facial hair that comes between the sealing surface and the face, and requires fit testing before first use and at least once a year. NIOSH is blunter and says even a day or two of stubble can reduce protection. It adds that people with beards fail fit tests, and it doesn’t endorse beard bands. Manufacturers agree. Moldex and 3M both warn that beards can stop a mask sealing.

Those are workplace rules, and a hobbyist isn’t covered by them. The reason behind them still applies. 3M’s pages say “For industrial/occupational use only. Not for consumer sale or use,” and they assume a written program with training, a medical evaluation and a fit test. Without that, treat the numbers on the box as the best case.

How do the options compare?

This comes from the manufacturers’ own pages and data sheets and from NIOSH, OSHA, EPA and CDC, not from a lab test. Weights are the facepiece without filters unless noted. Cost tiers are relative, from $ (cheap) to $$ (noticeably more), because none of these pages list prices.

Respirator	Type	Filters it takes	Exhale valve	Weight	Filter cost	Fit test notes
3M 6200 (my pick, 3M page)	Reusable half mask, thermoplastic elastomer	P100 filters (2091, 2097) or combination cartridges such as the 60921	Yes, replaceable	About 82 g	$ for P100 filters, $$ for combination cartridges	Small, medium, large. 3M sells taste test kits
3M 6500QL · Amazon	Reusable half mask, silicone, quick latch	Same 3M bayonet filters and cartridges	Yes, Cool Flow	110 g	$ to $$	Small, medium, large. The latch lets the mask hang at your neck
3M 7502 · Amazon	Reusable half mask, silicone	Same 3M bayonet filters and cartridges	Yes, Cool Flow	135 g	$ to $$	Small, medium, large
GVS Elipse P100 · Amazon	Half mask, thermoplastic elastomer, replaceable filters built in	P100 only	Yes, large central valve	About 130 to 138 g with filters	$ to $$	Two sizes plus XL. No fit test guidance on its page
Honeywell North 7700 · Amazon	Reusable half mask, silicone	North N-series, including P100	Yes	130 g	$ to $$	Small, medium, large. No fit test guidance on its pages
Moldex 7000 · Amazon	Reusable half mask	P100 disks (7940) or 7740 filters	Yes	About 98 to 100 g	$	Small, medium, large. Suggests a bitter test or a PortaCount
3M 8210 · Amazon	Disposable cup	N95, built in	No	Not listed	$ per mask	One size. NIOSH says it may be harder to pass a fit test than a half mask
3M 8233 · Amazon	Disposable cup	N100, built in	Yes	Not listed	$ per mask	One size. Foam seal and adjustable noseclip

Notes. 3M’s U.S. pages don’t list a weight for the 6200, so the 82 g is from 3M’s international data sheet. Moldex’s 98 to 100 g is from its European data sheet. The 3M 8233 is rated N100, not P100. That’s the same 99.97 percent without the oil resistance, and per NIOSH the N only matters if oil mist is in the air. Dust, spores and fibers aren’t oil. 3M’s 8293 is the P100 disposable.

How do I rank them for dusty, moldy, asbestos era buildings?

All three are particle problems, so the field is reusable half masks with P100 filters. Past the first pick, which one seals on your face matters more than the order. This ranking comes from published specs, not a lab.

1. 3M 6200 with 2091 or 2097 filters. A reusable half mask with replaceable high efficiency filters is the type EPA names for asbestos work, it sits above CDC’s N95 floor for mold, and at about 82 g it’s the lightest mask in the table. The same filters fit the 6500QL and 7502, so you can change facepieces without changing filters.
2. 3M 6500QL or 7502. A silicone seal, which 3M describes as soft but firm, and the Cool Flow valve that 3M says releases warm, moist breath. They weigh 110 to 135 g and take the same filters. The next step if the 6200 won’t seal or runs hot.
3. GVS Elipse P100. Filters built in and replaceable, roughly 130 to 138 g with them on, and P100 is all it does, which is all these hazards need. GVS’s data sheet lists both asbestos and mold among its uses. The downsides are two sizes plus an XL and no fit test guidance.
4. Moldex 7000. About 98 to 100 g, P100 filter disks, and a wide flange Moldex says fits more face shapes. Moldex’s U.S. pages list latex as “Yes,” so check if you’re allergic.
5. Honeywell North 7700. Silicone, 130 g, and Honeywell lists P100 among its N-series filters. It sits last of the reusables only because its pages say less about fit testing than 3M’s or Moldex’s.
6. Disposables (3M 8210, 8233, 8293). CDC’s floor for a moldy building is an N95, so a disposable has a place on a short, dry look. OSHA and EPA rule them out for asbestos, and a half mask is easier to fit.

What’s wrong with the 3M 6200?

Plenty, and you should know before you buy it.

• It’s the facepiece only. 3M’s page says a replaceable cartridge is not included. The link on my gear list is the mask. Filters are a separate buy.
• It’s a half mask. Your eyes are exposed, so see the goggles point above.
• It has a ceiling. Up to 10 times the OSHA limit, particles only, never in dangerous or oxygen deficient air. You don’t know the concentration in a building nobody has measured.
• It isn’t silicone. 3M lists a thermoplastic elastomer facepiece for the 6200 and advertises a silicone seal and the Cool Flow valve on the 6500QL and 7502. Its 6200 page doesn’t mention that valve.
• It’s sold for workplaces. See the 3M wording above.

The case for it is plain from the specs. It takes the P100 filters these buildings call for, it’s the lightest mask in the table, the filters sit in the cheap tier, and they carry over if you move up to a silicone 3M mask. Fit decides the rest.

What does this look like on a real explore?

The French mansion had bats in the wine cellar, close enough that one went past my ear, and an upstairs room carpeted with dead bees. The smell is the thing the camera can’t carry. CDC lists bird and bat droppings and old buildings among histoplasmosis risks, says large amounts of droppings should go to professional cleanup companies, and notes that construction workers can wear N95s. A P100 filter deals with particles. It won’t tell you which room was the problem, and it doesn’t touch gases.

At Kentucky Speedway the suite tables were dusty, and the pedestrian tunnel under the track was lit and felt like 50 degrees. Dust is a filter problem. A closed in tunnel is a question about the air itself, which no filter answers.

The rest of the kit is on the gear list, and the safety side of how I explore is part of my guide, How to Find Abandoned Places.

The best respirator is the one that passes a fit test on your face, wearing P100 filters, in air that has oxygen in it.