Watching Out for Asbestos Tape on Ductwork (How to Spot It)
During the 20th century – particularly from about the 1920s to 1970s – asbestos was one of the hottest building materials on earth. Manufacturers were tripping over each other to introduce new asbestos products and builders installed these products into countless homes nationwide, including right here in Arvada. At the same time evidence was growing that asbestos represented a potentially deadly threat, and starting in the late 1970s the government dramatically curtailed its use. In this guide, the team at Steve's Air Duct Cleaning look at the subject of asbestos tape on ductwork.
What is Asbestos?
Asbestos is a naturally occurring mineral that has long been recognized for its outstanding heat resistance. People first became aware of asbestos thousands of years ago but its use was extremely limited until the late 19th century. At that time it was first mined on an industrial scale and over the subsequent decades used to create all manner of products, including asbestos duct tape which was first used in the mid-1940s.
Asbestos duct tape was installed in countless homes and was touted for its durability, fire resistance and heat resistance. It was used primarily to seal or reinforce ductwork and was typically applied around joints and seams between sections of ductwork. In many homes, that is where it remains to this day.
asbestos • a naturally occurring group of fibrous silicate minerals valued for their strength, heat resistance, and insulating properties. For decades it was widely used in building materials, automotive parts, and fireproofing products before its health hazards were fully understood.
If It Was Dangerous Why Was It Installed in Homes?
While the dangers of asbestos were pretty well established in the early 20th century manufacturing heavyweights used their influence to make sure much of that evidence never saw the light of day. In that sense, the asbestos saga is not unlike what happened with cigarettes.
As a result, a lot of contractors installing asbestos-containing products, including asbestos tape, had no idea that the duct tape they were using on homes represented a danger to anyone. To them, using asbestos tape made sense because of what they perceived to be its benefits, including:
- Fire resistance: Asbestos was, for all practical purposes, fireproof. So installing asbestos tape in homes seemed like a genuinely smart thing to do.
- Insulation capabilities: Ducts transport heated air throughout the house. By using asbestos duct tape heat loss between the furnace and the destination room was reduced.
- Durability: Asbestos was not only fireproof, it was also very durable. This quality too argued in favor of its use.
Asbestos tape was most often (though not exclusively) used in areas like the basement and attic where ducts were exposed.
Health Risks Posed by Asbestos
When newly produced and installed asbestos tape (and, indeed all asbestos-containing products) pose virtually no health risk. Over time, however, as the tape begins to dry out and fall apart it begins to release the potentially deadly asbestos fibers into the air. The more fibers it releases the greater the risk. Over time if the problem is not addressed people in the home become susceptible to developing asbestosis, a condition that can cause permanent scarring of the lungs. Long-term inhalation of asbestos fibers can also lead to mesothelioma, an aggressive form of cancer that attacks the lining of the lungs and heart.
How to Spot Asbestos Duct Tape
Since virtually every HVAC duct system uses duct tape it can be difficult for the untrained eye to recognize asbestos tape. As an experienced provider of HVAC cleaning, we've encountered it enough to be able to know exactly what to look for. So read on to learn how to spot asbestos tape on your ducts.
The age of your home
The government began restricting the use of asbestos in the late 1970s but there was no outright ban in place until 2024. Fortunately, after the dangers became public companies began to voluntarily eliminate asbestos from their products. That process took a few years and so even into the early 1980s, it is possible that asbestos tape was still being used.
So if your home was built between the mid-40s and mid-80s there is a chance it may contain asbestos duct tape.
Appearance of the tape
Everyone is used to duct tape having a shiny gray surface. But asbestos-containing duct tape looks a little different. Common characteristics of asbestos tape include:
- Off-white, white or light gray color.
- A cloth-like texture.
- Powdery or chalky residue around the tape.
- The tape may have dried out and is now brittle or cracked.
Location of the tape
Asbestos tape is most commonly found in places where ductwork is exposed like the basement, attic, crawl space, and the area immediately around the furnace.
If you find asbestos tape in any of these areas do not touch it or try to remove it. If it is asbestos tape disturbing it may release millions of tiny asbestos fibers into the air making the situation much worse. Also, don't try to vacuum up any powdery residue. Just leave everything as it is and call an asbestos removal professional.
This video does a good job of explaining what asbestos tape looks like.
Asbestos: the Good, the Bad, & the Ugly
Your Options If A Professional Confirms the Presence of Asbestos Tape
If you call an asbestos removal pro and they confirm the presence of asbestos tape you will have 3 options:
- Leave it alone: As we said earlier asbestos products do not represent a threat if they are new or otherwise intact because none of the dangerous fibers are being released. So if the removal pro discovers your asbestos tape is still intact you will have the option of just leaving it alone.
- Encapsulation: If the asbestos tape has started to break down but is still in relatively good shape you may be given the encapsulation option. With encapsulation, a sealant is applied to the asbestos tape locking the fibers in place and preventing their release.
- Removal: If the tape shows obvious deterioration or damage, removal may be the only reasonable option.
FAQs About Asbestos
Yes. In older homes and buildings, asbestos may be found in duct insulation, tape/mastic, vibration dampeners, or nearby boiler and furnace insulation. If these materials are intact and undisturbed, fibers are less likely to become airborne; damage or deterioration raises the risk. Our first step is always to visually assess for suspect materials and stop work if we see anything concerning.
We do not disturb suspect materials. If we encounter possible asbestos, we pause cleaning and recommend testing by an accredited lab or evaluation by a licensed asbestos professional. Only after written clearance or proper abatement do we resume HVAC cleaning, using negative-pressure equipment and HEPA filtration to control dust. This approach protects your indoor air and keeps the project compliant with local rules.
Buildings constructed or renovated before the late 1980s often warrant caution, especially if you see cloth-like wrap, gray/white tape, or brittle insulation on or near ducts. Flaking, fraying, or damaged materials are red flags. A qualified inspector can collect samples safely—homeowners should never scrape or remove samples themselves. Testing provides a clear yes/no so the right plan can be made.
If suspect materials are intact and undisturbed, risk is generally lower, but airflow, vibration, or a filter change could still disturb fibers. If you suspect damage or see debris, avoid running the system and minimize access to the area. Contact a licensed asbestos professional for guidance and, if needed, temporary containment. Once the area is cleared or abated, we can clean and re-balance the system.
A licensed abatement contractor will develop a containment and removal or encapsulation plan specific to the material and location. After abatement, a clearance inspection or air testing is typically performed to verify the area is safe. We then perform a thorough HVAC and duct cleaning—using HEPA-filtered negative air machines, register-by-register cleaning, and final filtration checks. This sequence helps ensure fibers aren’t reintroduced to your living spaces.
Most Americans are under the impression that the asbestos problem was solved 40 or more years ago. But that is only partially true. Many of the asbestos-containing products – including asbestos duct tape – installed before restrictions were implemented remained in place, and are still in place today. If you suspect your home contains asbestos tape contact an asbestos testing and removal company asap.
For Expert Duct Cleaning in Arvada Call Steve’s
Even if your home does not contain asbestos tape you should make sure to keep your ducts and vents clean at all times. Steve's offers a professional vent cleaner service as well as expert air duct cleaning. To schedule either, give us a call at 720-419-7792 today during normal business hours.
Start Breathing Easier.
Your air ducts are the lungs of your home and keeping them clean keeps you and your family healthier and your HVAC equipment working optimally.
