Chimney Health Hazards: Things You Should Know

Our chimneys, in conjunction with the fireplaces they support, help to provide us with much warmth during the colder months.  They can, however, have various adverse effects on our health.  Of course, one shouldn’t live in fear of this, though it is wise to have a working knowledge of chimney and fireplace health hazards.  Let’s look at some ways in which your chimney may be more foe than friend.

creosoteCreosote Exposure

Creosote is an oily black substance that can potentially build up inside your chimney flue because of incomplete wood combustion.  Not only does this stuff sound nasty, but it can also produce some undesirable health effects, such as:

  • Skin Irritation. Physical contact with creosote buildup can cause rashes and other major skin issues.
  • Eye Irritation. Creosote debris that gets on/in the eyes will irritate them, sometimes to the point of feeling burning sensations or actual chemical burns.  Sensitivity to light is also possible.
  • Respiratory Problems. Breathing in creosote particles for a length of time often catches up with the person exposed, as lung and other respiratory issues may develop.
  • Abdominal Issues. Creosote carries with it the potential to irritate both one’s kidneys and liver.
  • Mental Problems. Serious exposure to creosote will cause seizures and confusion in some people.
  • Cancer. Though this greatest health effect has not occurred often from chimney use, creosote exposure does have the potential to cause skin cancer.

"Soot" covered youngster

No children were harmed in this photo. (Source:

Chimney Soot Inhalation

Chimney soot is another contaminant resulting from incomplete combustion, and it forms when wood does not burn hot enough (less than 284 degrees).  This powdery brown or black dust sticks to the inside of chimneys (sometimes escaping into the air) and carries a few risks similar to creosote, such as:

  • Lung Hazard. Like creosote, if chimney soot is inhaled in great enough amounts, it has the potential to either irritate the lungs or cause lung diseases.
  • Respiratory Risks. In conjunction with lung problems, general respiratory infections may crop up due to soot inhalation.

Carbon Monoxide Poisoning

Carbon monoxide is a hazardous gas that is odorless, colorless and tasteless, making it notoriously hard to detect.  The gas is a result of incomplete combustion due to insufficient oxygen to finish oxidation.  In this case, it doesn’t make it to the carbon dioxide form.  When Carbon monoxide makes it into the air, several health problems may emerge:

  • Flu-like Symptoms. Carbon monoxide taken into the body in small amounts may mirror flu characteristics, including fatigue, nausea, confusion or headache.
  • Organ Troubles. The more carbon monoxide you inhale, the worse the impacts on your health.  Breathing in large quantities (At once or over time) of this gas may result in brain damage or heart problems, and at its worst even death.

chimney swift nestChimney Swifts and Histoplasmosis

Chimney swifts are small, brownish black birds with an affinity for taking up residence inside residential chimneys.  The birds themselves are little more than annoying, though what they leave behind may cause problems.  Their droppings may cause histoplasmosis, a respiratory infection caused by histplasma capsulatum, a fungus.  Symptoms generally look like a mild illness or flu, and include:

  • Chronic Cough. Coughing a lot?  It might be a sign of a larger problem from your chimney.
  • Chest Pain. Chest pain is never something to ignore, and if you knowingly have chimney swifts, it may be worth it to mention to the doctor.
  • Fever, Chills or Sweats. Though usually associated with the flu, these symptoms may be the result of extreme buildup of histplasma capsulatum in your chimney.
  • Lack of Appetite and Weight Loss. While you may simply be under the weather when this happens, if this or any of the above symptoms have joined forces, those chimney swifts may be to blame.

None of these things are particularly enjoyable to cope with.  So, the underlying message is simple: take precautions and clean your chimney.  Chimney sweeps can determine if any internal structures of your chimney are damaged, contributing to buildup problems.  Additionally, chimney sweeps will remove creosote, soot and chimney swift deposits, resulting in decreased health risks.  You may also consider having your home checked for carbon monoxide and also install a carbon monoxide detector.  With a better knowledge of chimney risks, you can now enjoy wintertime fires more responsibly!

5 thoughts on "Chimney Health Hazards: Things You Should Know"

Alleen says:

You should probably remove the part of this page that makes the claim that Histoplasmosis is associated in any way with chimney swifts. It is not. It is a fungus that grows in soil associated with large bat colonies and chicken farms. Not chimneys. Not swifts. I don’t blame you for believing it because so many chimney sweep sites have been scaring people to get business. The same claim is on many websites. But look for any actual evidence that Histoplasmosis has been tied to any chimney swift and you won’t find any.

If someone has swifts in their chimney they can wait until September and then have it cleaned. The fire hazard of not cleaning a chimney is a HUGE health — no need to frighten people with made up stories about diseases.

Mike says:

I’ve been in a new home for three weeks and smell soot every other day. I am having my chimney cleaned next week. Should I be concerned for the three weeks my family has been breathing it in? Every other day it smells like a fire is going…

High's Chimney Service Inc. says:

Short answer, not really. Longer answer is that anything we breathe beside good clean air… well, we shouldn’t breathe it. But it’s unlikely you’ve had significant exposure to anything you need to worry about from a health standpoint.

I’d be more concerned just because you don’t want to live with the stink. Makes for being unable to enjoy your house otherwise. When you say new home I presume you mean new-to-you but the house itself isn’t new (no good reason for smells like that from a brand new house)

A lot of things can cause a stink like that, but bottom line is that soot has to be present or it has to have soaked into the masonry. If it’s soaked into masonry, while most people try to “fix it” with chemicals etc. what it usually actually takes is removing the masonry and rebuilding or relining with stainless steel.

The other thing to be thinking about is why it got that way in the first place. Is it a moist fireplace below grade? Is it 20 years lack of cleaning? Is there creosote behind the tiles? Get to the bottom of it and fix it in a way that it stays fixed!

Good luck, hope it’s an easy solution.

Janet says:

I’ve just removed a section of ceiling in an old house. A lot of soot (and other dust / plaster) fell down. Although I was wearing a dust mask, and kept going out to get fresh air, I’m sure I must have inhaled a lot of soot. I’ve got a bit of an ache in my chest this morning and a cough. Is there anything I can do to ‘clear my lungs out’? Is breathing deeper better – eg vigorous exercise – or would that actually drive particles further in?

High's Chimney Service Inc. says:

I’m not a doctor and I won’t pretend to be one. So said, my experience, which includes a lot of lungs full of dust over a lot of years, is that lungs do seem to clear themselves out in a day or so. If you are still concerned after what you consider to be a reasonable length of time, by all means get it checked out.

No fun; good luck.

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