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Building Science

How Worried Should You Be About Asbestos in Older Homes?

From duct tape to pipe wrap to vermiculite insulation, older homes can contain a lot of asbestos

Image 1 of 3
Older homes can contain a lot of asbestos products, such as the white duct tape you see here.
Image Credit: Images #1 and #3: Energy Vanguard
Older homes can contain a lot of asbestos products, such as the white duct tape you see here.
Image Credit: Images #1 and #3: Energy Vanguard
Chrysotile asbestos fibers
Image Credit: Image #2: U.S. Geological Survey
Vermiculite attic insulation is sometimes found in older homes and is often contaminated with asbestos because of the Libby, Montana mine where it originated. In this Austin, Texas home, the vermiculite was hiding beneath blown cellulose insulation.

Asbestos was a popular material for most of the twentieth century, mainly because of its ability to insulate and act as a fire retardant. In fact, it’s still used heavily in some parts of the world, such as India and China. We know enough about the risks now, though, that it’s banned outright in more than 50 countries and banned for some uses in the U.S.

But how worried should you be if you find it in your home?

Asbestos in the home

One of the places you might find asbestos in a home is the duct system. The white tape you see in the photo (above right) is of the type that often contains asbestos, although you don’t really know without sending a sample to be tested in a lab. If you have an older home with rigid metal ducts, as shown above, it might have white fabric tape like the tape in the photo.

The video below, from the 1920s, shows two workers applying a thick insulation material to the boiler and ducts in the home. (Skip to the 6:20 mark to see that part.) That stuff probably had asbestos in it.

Other places you might find asbestos are:

  • Floor tiles
  • Ceiling tiles
  • Vermiculite insulation in attics and walls
  • Roofing and siding
  • Artificial ashes and embers in gas fireplaces
  • Textured paint and patching compounds (banned in 1977)

For more information, see the web page on asbestos in the home at the U.S. Consumer Products Safety Commission.

What health problems does asbestos cause?

The big three diseases listed on all the asbestos web sites are:

  • Asbestosis
  • Mesothelioma
  • Lung cancer

All of them result from asbestos fibers getting into the lungs. Asbestos occurs in six mineral types, and all have fibers that are harmful to lung tissue, getting embedded in lung tissue and causing inflammation, scarring, and eventually tumors. Image #2 (below) shows the fibers of the chrysotile type, which makes up about 90% of all commercially available asbestos.

Asbestosis is an inflammation leading to shortness of breath, coughing, and other breathing problems. Mesothelioma is a cancer of the protective membrane around the lungs. Lung cancer is well known because so many people succumb to it each year, mostly from smoking. (Both of my parents died of lung cancer; both had been smokers.)

The World Health Organization says that asbestos exposure leads to these three diseases killing more than 107,000 people worldwide every year. That’s a big number. In addition, many more people die of other asbestos-related diseases or suffer various levels of disability.

The problems with asbestos have been known for a long time. The ancient Persians and Romans used the stuff and may have noticed health problems associated with its use. In 1902, asbestos was added to a list of harmful industrial substances in England. Nellie Kershaw, who worked in a factory spinning asbestos fibers into fabric, was the first officially diagnosed case of asbestosis. She died in 1924. (See the “Discovery of Toxicity” section in the Wikipedia article on asbestos.)

The consensus in the medical community is that asbestos is dangerous, which is why it’s classified as a known human carcinogen. There’s no debate on that point, and the lawyers have had a field day litigating asbestos health problems.

Are you at risk?

If you live in a home built before 1980, there’s probably some asbestos in it. The stuff was used in a lot of different building materials. But here’s the good news for homeowners: The people who get asbestosis, mesothelioma, and asbestos-related lung cancer are almost always people who fall into one of these groups:

  • Asbestos mine, mill, or transportation workers
  • Asbestos product workers (e.g., shipbuilders, construction workers, pipefitters, auto mechanics)
  • Families of asbestos workers (because of fibers brought home on clothes and in hair)
  • People who live near asbestos mines or mills

Another group being watched because of high asbestos exposure are the people involved in the rescue and cleanup efforts in New York City after the 9/11 attacks in 2001. It’ll be a while before we know how bad it really was because it generally takes 10 to 40 years for symptoms to appear.

Asbestos in some form is in millions of homes, but I haven’t been able to find statistics on the health effects of asbestos exposure in the home. That doesn’t mean they aren’t there, but the cases of health problems from occupational exposure dominate. The only mention of health problems from exposure in the home that I could find are related to people living with asbestos workers or living near asbestos mines or mills.

That doesn’t mean you have nothing to worry about, but I think that the National Cancer Institute’s view is one to keep in mind:

Everyone is exposed to asbestos at some time during their life. Low levels of asbestos are present in the air, water, and soil. However, most people do not become ill from their exposure. People who become ill from asbestos are usually those who are exposed to it on a regular basis, most often in a job where they work directly with the material or through substantial environmental contact.

In other words, don’t panic.

What should you do about asbestos in the home?

If you do find something in your home that you think may contain asbestos, rule number one is: Don’t mess with it!

If you see white tape on your ducts, as shown in the photo above, or vermiculite insulation in your attic, as shown in Image #3 below, it’s probably not causing a problem as long as it’s undisturbed. (Vermiculite insulation, which may contain the tremolite types of asbestos, is a big enough topic that I’ll write a whole article about it later.)

Asbestos isn’t like radioactivity, which can be a hazard because it constantly emits radiation. Asbestos only becomes a problem if it becomes airborne and gets into your lungs at a high enough dose.

If you’re concerned about a particular material in your home, you can call an asbestos inspection company to come in and have the material tested. They’ll take samples using the approved protocols and send them to a lab for testing. When you get the results back, the company you hired can help you decide what your next steps should be.

As long as you’re not planning to make changes to the home that require disturbing it, it might be best just to leave the material alone. If the suspected asbestos-containing material is friable, encapsulating or enclosing the material can help prevent the fibers from getting into the air. But this’s not a job to be taken lightly, so you should hire a pro. The Environmental Protection Agency has a good web page for homeowners on what to do if you may have asbestos in your home.

A word to the pros

For those who work in the fields of HVAC, insulation, plumbing, home performance, or remodeling, and who deal with older homes, you’re likely to come across many homes with materials that may contain asbestos. You owe it to yourself and your family to take all the proper precautions when working with these materials.

You may not have the exposure that killed Nellie Kershaw after only seven years of spinning asbestos fibers into fabric. You may not even get enough exposure over a career to cause problems. Still, do you want to take that chance? I can tell you from my experience with asthma as a child that having difficulty breathing is no fun at all. And from seeing both of my parents die of lung cancer, I can tell you that’s not a nice way to go.

If you spend a lot of time in the attics, basements, and crawl spaces of older homes, don’t mess around with materials that may be dangerous. Whether you’re an employer or employee, check out the OSHA page on asbestos and be safe.

Use caution

We humans are a curious and ambitious lot, always striving to understand the world around us and improve our circumstances. If a material exists anywhere near the surface of the Earth, we’ve found it and exploited it for its useful properties. Like the toddler touching the hot stove, though, we often don’t discover the harmful properties until after the damage is done. That is also true of asbestos.

The stuff is out in the world now, and we must deal with it. The key is to use caution and know what you’re dealing with.

More Information

Wikipedia asbestos page

EPA asbestos page

OSHA asbestos page

National Cancer Institute page

World Health Organization page – Contains a good description of the six types of asbestos minerals.

Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. Check out his in-depth course, Mastering Building Science at Heatspring Learning Institute, and follow him on Twitter at @EnergyVanguard.


  1. user-973188 | | #1

    Asbestos tile resource...
    Ahhh, asbestos. Out home has floor tiles that most likely contain it, so we're leaving them the hell alone. We'll cover it with wood or Marmoleum at some point when we have the $$.

    I found an online resource that lists US floor tiles that were made from 1954-1980 that contain "the miracle ingredient".

    It includes scans of tile catalogues (in PDF) so you can see what was the "hip" look in American homes back in the day. Our tiles are from 1968... "Imperial Modern Sable Gray", or "Is that spot a cat turd or is it the tile?"

  2. Expert Member
    Dana Dorsett | | #2

    Blower door testing homes with asbestos...
    ... is expressly illegal in Massachusetts, which complicates some of the retrofit thermal upgrading of housing stock.

    There are MANY homes in New England with ancient steam boilers where both the boiler and some of the distribution plumbing is insulated with asbestos. After 75-125 years of service the condition of the insulation on some of these boilers is downright miserable:

    But the data on negative health effects attributable to living in those houses with the crumbly snow-man boilers isn't very deep. If it were a very high risk it should be readily discernible in the health statistics, given the size of the installed base, and how long people have been living with those exposures.

    Curiously, SFAIK it's NOT illegal to blow insulation into empty wall cavities in those homes, even cavities that have (or previously had) steam heating distribution plumbing in them and clearly visible asbestos on those systems. That makes me somewhat curious as to the basis for banning blower door testing. My guess is that it's more theoretical than actual measured problems with running blower door tests in homes with asbestos.

  3. charlie_sullivan | | #3

    light fixtures
    One more place it's found, and the one I found in my 1970 house, is in surface-mount light fixtures. There's a thin layer of foil-faced insulating board above the bulb, which unfortunately is crumbling.

  4. fitchplate | | #4

    A miserable death …
    A miserable death …

    For those who might dismiss this issue, be advised just how unsuspecting and innocuous mesotheiloma is. My best and life-long friend (a journeyman plumber in Ontario) developed odd painful, breathing problems and two years later he died at 66 (on Manitoulin Island). The diagnosis was mesotheiloma. He had a vague memory of only one job, a commercial installation of an asbestos lined gas pipe line, he worked on one winter about 34 years earlier. Otherwise, he was unaware of any other source of asbestos exposure. I suspected that it was not the asbestos exposure he knew about, but rather the exposure he did not know about that took decades to eventually result in a malignant disease. His death was long, drawn out and extremely painful.

  5. Richard_Brand | | #5

    A $1-billion problem for Canberra
    Last Tuesday the Australian Federal Government announced a A$1-billion loan to the Australian Capital Territory government. The ACT government basically runs the national capital, Canberra. The loan is to enable the government to buy back and demolish 1021 homes which had loose fill asbestos roof installation by a company called Mr Fluffy. In the next five years, all the houses will be demolished and the land scraped clean. All houses built before 1980 are likely to need a full assessment before being sold or undergoing renovations. Ultimately all the costs will be entirely born by the residents of Canberra. See

  6. Expert Member

    National shame.
    We Canadians should hang out heads in shame at the way our governments have, over the years, defended and promoted an industry that caused so much suffering.

  7. Expert Member
    Dana Dorsett | | #7

    A miserable death indeed (response to Flitch Plate)
    Brake linings were a common source of airborne asbestos, affecting many people with no other known exposures. It showed up on statistics back in the 1980s, when comparing mesothelioma incidence with proximity of the dwelling to traffic intersections with stop lights or stop signs.

    That was part of the evidence presented during legislative investigations that eventually led to the banning of asbestos in brake linings in the US.

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