I think you can read between the lines here. I had on a typical n95 mask while doing a little demo. I didn't have raised suspicions about there being asbestos in the walls, as I already researched my home's primary wall material prior and it's not prone to the stuff. But, after removing a few SF of board I noticed a different breed, and the label is "national gypsum company" "fireproof GYPSUM W..." label cuts off. It's the fireproof part that raised my red flag. I bagged what I took off, cleaned the area, and am sending a sample off to a lab for testing.

My throat was a bit dry after the work. I don't know if I'm overthinking, but in googling around, pretty much the only thing people will tell you is to not use n95 for asbestos. Great and all, but my question is whether n95 provides ANY protection? Looking at the micron sizes of asbestos and the filter, it would seem it should filter them, so is it catching 95% and obviously for this hazardous material you want that extra 5% covered, or do these fibers penetrate n95 material?

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  • recently ran into an issue with asbestos and there are several resourses like this which says: No level of asbestos exposure is considered safe. However, most problems arise after years of repeated and long-term exposure to the carcinogen, so even if you were exposed its similar to eating a raw egg, you probably won't get sick but you might
    – depperm
    Aug 14, 2019 at 12:34
  • 1
    1 day or prolonged exposure? see mayoclinic.org/diseases-conditions/asbestosis/symptoms-causes/…
    – Solar Mike
    Aug 14, 2019 at 12:56
  • Can you shoot a photo of the material in question? Aug 14, 2019 at 18:33
  • 6
    "Throat dry" is to be expected after working with lots of dust of any origin. Aug 14, 2019 at 19:11
  • 1
    A dry throat probably just means you weren't drinking enough water. Which is very common when working with a face mask on. Aug 14, 2019 at 19:34

5 Answers 5


It's asbestos, not kryptonite

It's not that toxic, or it would have never attained its status as a popular material in the first place.

Doctors started noticing that laborers who worked every day in asbestos plants or installing asbestos for 20 years... were having serious lung problems, as well as in some cases lung cancer. The process of identifying this was not fast. However once it was proven that these injuries and cancers were coming from asbestos, the companies who employed these laborers set up trust funds to pay legal claims.

Access to the trust funds requires some documentation, but it's easy work for lawyers. There aren't any great Perry Mason moments in these legal actions; the trust funds are already established. Yet, some lawyers will collect 1/3 "contingency fee". (they're paid if you win).

As such, they blast advertisements 24x7 in their desperate search for asbestos workers who might qualify for the trust fund.

The real carcinogen here is advertisements.

The only reason there's any hysteria at all about asbestos is this carpet bombing of ads frothing people up into thinking asbestos is demon dust. The government decided there was no need for the government to produce calm and reasonable Public Service Announcements; community education "can be left to the private sector".


Anyway, that's why you are gripped with fear. The problem isn't the asbestos, it's the level of inherent faith you place in commercial advertising, without even realizing it. It is simply impossible for reason to be heard against the onslaught of adverts.

The fact is, incidental exposure (a day or two in a lifetime) to material that probably doesn't even have a high concentration of asbestos, is such a low risk as to be effectively zero. Ordinary masks are sufficient to manage that risk.

Meanwhile you have the government trying to communicate to employers (read: cheap and old fashioned) and off-the-curb, never-see-em-again day-labor employees (read: non-English speakers) how to protect themselves from daily, career-long occupational exposure to asbestos, so we don't get any new cases. Their advice is to use tip-top gear, because that adds up when you do it everyday for years. In that context, true, you want better than N95, but the way they communicate that to cheap employers is "N95 masks don't work".

Which is not true at all, in your incidental case. You are much better off having used that mask, mainly due to other risks.

So if you want to be part of the mesothelioma moral panic, just keep in mind negative thoughts are far more carcinogenic than whatever got through that mask.

One other thing: Gypsum is fireproof. Drywall is gypsum and drywall is used for firestops.

  • 1
    I wouldn't be surprised if a related piece is: No manufacturer of N95 masks is willing to go through the testing needed to certify that the masks will protect sufficiently against asbestos due to the liability involved and/or if they make other (asbestos "safe") masks then they would cannibalize their real money-makers if N95 were certified. I disagree with the employers being illiterate. Cheap - yes. Employees likely non-English speakers, yes (for a variety of reasons). (And employees being taken advantage of by the cheap (but not illiterate) employers - absolutely). Aug 14, 2019 at 19:15
  • 1
    @manassehkatz fair enough... Aug 14, 2019 at 19:50
  • Thanks for that! You reaffirmed my thoughts so that my stupid brain can calm the heck down. I didn't know that gypsum was actually fireproof, i just knew that it has a fire rating of x number of minutes. Cool, i won't sweat waiting for those test results! (still sent them in, to know how to proceed) Aug 14, 2019 at 20:28
  • @ Darren Levine I spent a whole summer back in the 60's re-bricking 4 steel heat treating furnaces with asbestos bricks with no masks... and then in the 70's using it to fireproof high voltage feeders. Luckily, absolutely no problems... so don't worry Darren
    – JACK
    Aug 14, 2019 at 23:25

According to CAL/OSHA the N-95 does not provide protection against asbestos.


Q: What is an N95 mask? A: An N95 mask is a disposable filtering facepiece respirator with two straps. When worn properly (with the mask making a tight seal with the user’s face), it can protect against hazardous airborne particles. N95 masks do not protect against gases, vapors or asbestos, and they do not provide oxygen. The “N” designation means the mask is not resistant to the effects of oil mists. For instruction on using filtering facepieces, see Using Disposable Respirators in English and Spanish.

  • 5
    Leave it to the government. That's a lie, but one with a purpose. OSHA serves employees and employers. They are telling employers not to send a man in for a day's work clearing asbestos with an N95 mask, over and over for a career. They are telling employees not to accept an N95 mask. This is about occupational exposure and does not bear on OP's case. Aug 14, 2019 at 17:39

Here are the facts: N95 or P95 masks mean it filters 95% of airborne particles as small as 0.3 Microns. Asbestos fibers range .10 to 90 Microns in size. So yes, your N95 mask DID filter out probably 80%+ of the airborne asbestos fibers from your breath. The reason it says they do not work online is because they do not filter out ALL fibers. But they do provide some protection. But that is no reason to fear. Here is another fact: Only 4% of people who had repeated, heavy exposure of asbestos for YEARS went on to develop disease. 4%.

  • Can you cite any sources for the 4% claim?
    – rmp251
    Apr 24 at 19:18

Just understand, asbestos is not the only material that deserves the reputation for generating lung cancer.

Believe it or not, repeated exposure to Pottery dust particles is another good one for causing cancer after 15-25years.

The problem has nothing to do with the asbestos material...it's the size of dust particles that you should worry about. Any dust particle below a certain size that can become embedded into lung tissue potentially can cause lung irritation and this irritation turn cancerous.

  • 1
    Yeah, asbestos, respirable silica, etc all have the same mechanism of action as carcinogens: the physical presence of a particle that far into the lungs that won't go away triggers a bunch of lung cells to grow around it to sequester it and try to break it down, but it won't break down, so the "grow cells to deal with this particle" mechanism doesn't turn off, and you get a tumor as a result Aug 6, 2022 at 2:50

Short-Term Exposure Fast Facts

Light, short-term exposure rarely causes disease

A one-off exposure from do-it-yourself renovation is not a major risk

Asbestos exposure is cumulative, so short-term exposures can add up

Disasters may cause extreme asbestos-exposure events

From Asbestos.com

I inhaled a lot of dust from sawing weatherboard on my first house about 40 years ago. Luckily. there has been no effects. OTOH, my father-in-law, a builder, did die from asbestosis.

From my understanding, you just need one fiber in the wrong place in the lung tissue, but the odds of that are very low from a single exposure such as yours. And the filter would have stopped most of it. So, I wouldn't stress about it.

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