my bathroom fan was dropping water so i went up to the attic and applied fiberglass insulation to the bare metal vent pipt from the fan out to the roof.

i was up in the attic for an hour wearing short sleeve t-shirts and no mask. When i came down, i started coughing (4~5 times an hour) and my arm felt very itch even after shower.

I did some research and learned that i should have been wearing long sleeve to protect my skin and wear dust mask to get protection from fiberglass. All similar posts online were about being exposed 10 minutes or less.

Should i go see a doctor?

7 Answers 7


Fiberglass can cause mild irritation but is not dangerous. You'll be fine.

  • 9
    This answer needs context. Fiberglass is dangerous, though likely not for the periods of time a typical homeowner is exposed to it.
    – DA01
    Commented Dec 15, 2014 at 8:57
  • 2
    I suppose breathing in anything for a lifetime is probably not good for you. I think in a DIY context, fiberglass can be considered safe (although maybe a little unpleasant).
    – Hank
    Commented Dec 15, 2014 at 16:21

Fiberglass can be bad for the lungs: http://www.lung.org/healthy-air/home/resources/fiberglass.html

However, for it to be a real issue, one needs a lot of exposure...typically someone that works with it daily as part of their job.

The amount of contact a typical homeowner would be exposed to in their lifetime is not likely something to lose too much sleep over.

For future reference, however, a cheap 3M dust mask is a good idea the next time you're up in the attic.

Odds are you are coughing due to dust in the attic more than the fiberglass.


Adding a little more detail above the other answers, plus recommendations.

Fiberglass is made of fibers of glass (duh!). When you inhale them into your lungs, they are not easily broken down by your body if at all. If you don't like the idea of getting wood or metal particles in your lungs, then you shouldn't inhale glass fibers either. For small amounts, you will be fine. You can wear a cheap dust mask to avoid this.

Furthermore, it's generally recommended that if you expose your skin to fiberglass you should take a cold shower. A warm shower expands your pores and some the fibers enter and cause irritation. On this count, the fiberglass isn't dangerous because your skin is continually growing out and/or expelling foreign substances. But you will save yourself some itching.


Many variables here but for most people this would not be a problem. I have been working on old homes for 30 years and have popped up into attics without proper gear countless times. Sometimes there is some residual irritation to lungs for a day or so and skin irritation form contact with fiberglass.
That said - Wear a mask, a good mask, not just a cheap paper, but N95 at least with foam seal and exhaust valve.


Fiberglass's main issue is when extremely small fibers make their way into the deep lung tissue. Long-term exposure can result in silicosis. Short-term exposure is extremely unlikely to result in anything other than short-term irritation of the throat, nasal passages, in some cases nose bleeds, and a cough. Coughing will clean the lungs of much of the fibers. The extremely small fibers that make it to deep lung tissue will be slowly removed from the lungs via lung fluids then Microphages (supposedly). Usually in the case of long-term exposure, chronic conditions will not appear for at least around 20 years later. It is debated whether inhaling Fiberglass is carcinogenic but we know that some industrial Fiberglass can be due to the binders used. They say that consumer household fiberglass insulation is not carcinogenic, but assuming it is, it would be estimated at about 4 - 7% of what asbestos is. So it's much better than asbestos in those terms, that's even if it is carcinogenic at all. Many people inhaled a lot of asbestos in their life and never even got any chronic illness, that being said obviously many also have. Acute Fiberglass exposure extremely likely will never lead to any long-term conditions what-so-ever. Long-term exposure could lead to silicosis/fiberosis over a period of ~20+ years due to scarring of lung tissue. Cancer is extremely unlikely in all cases unless you are working with specific industrial insulations, and even then, short-term exposure likely isn't much of a risk factor. If your house is contaminated, it's hell to fix (personal experience) but it needs to be done. Fix source of contamination first, then section by section hepa vacuum and wipe down with damp cloths, use an led light to inspect surfaces.

In your case, you should be perfectly fine. Might cough a little. Take a cold shower and if you were wearing everyday clothes then I would wash them a few times then run a rinse cycle to clean it out of machine. More likely you're coughing from dust and not specifically just fibreglass. A lot of the stuff online is ridiculous so don't pay much attention. There's articles about how the resins on Fiberglass will cause brain cancer blah blahh, fact is short term exposure and occasional DIY shouldn't ever cause any problems, always wear proper protection. Now you know.

I was on a fiberglass dust contaminated house for 4 months. I had some minor issues but they've all cleared up after a number of weeks. My chance of problems down the road? Probably slim to none. Even red meat can cause cancer, don't lose sleep over an hour in the attic

  • Curious Charles, how did the house get contaminated with fiberglass?
    – user53305
    Commented Apr 30, 2016 at 3:18

I would wait a day or two, and then see a doctor if it doesn't go away. I once had to army crawl through insulation to run some cabling in my house. Took me about an hour as well, and I didn't wear a mask either. The coughing took a few hours to go away, but I am fine :)

Insulation is nasty stuff though - I would highly recommend a gas mask and long sleeves next time!

  • Ps: I am not a doctor, and remember that it is always better to be safe than sorry. If your gut tells you to see a doctor, then go do it! Commented Dec 15, 2014 at 3:54

Fiberglass is probably not that good for you just like many other things you breath in on a daily basis. I would recommend that next time you wear a dust mask and goggles. The good news is that it does not cause cancer. It does case skin, eye and lung irritation. I have had long term exposure to fiberglass over the past 35 years and so far I have not noticed any effects. My co workers and I often asked several industrial hygienists about fiberglass and they all said the same thing. "studies are not conclusive" .. They were more censored about asbestos, lead, mold and blood born pathogens. I guess I have built up an immunity to fiberglass myself because it does not bother me that much. I should wear a dust mask but I just don't. I found that the dust in the fiberglass had a much greater effect on my breathing than the glass itself. Old insulation is the worst in my opinion. Everyone has different tolerance levels to things they inhale so please take care of yourself. I just would not be too concerned about 1 hour of exposure.

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