Short answer: Yes, soot can be harmful. It is made of very fine particles that can reach deep into the lungs, and it can carry chemicals from whatever burned. Short term exposure can irritate the eyes, nose, throat and lungs, and people with asthma, heart or lung disease, children, pregnant women and older adults are at higher risk.
Soot is the black residue left after a fire. It coats walls, ceilings, furniture and air ducts, and it can spread through the whole house even when the fire was in one room. Many people ask whether soot is dangerous and whether they can clean it themselves. This guide explains the risks and how to stay safe.
What soot is made of
Soot is mostly carbon, in very fine particles. Depending on what burned, it can also carry acids, metals and chemicals such as polycyclic aromatic hydrocarbons, known as PAHs. Burning plastics, synthetic fabrics, foam and electronics creates more complex residues than burning wood alone. The finest particles, known as PM2.5, are small enough to reach deep into the lungs.
How soot can affect health
- Irritated eyes, nose and throat
- Coughing, wheezing and shortness of breath
- Asthma attacks in people with asthma
- Headaches
- Skin irritation where soot touches the skin
Long term exposure to fine particles is linked to heart and lung problems, which is why soot should be removed thoroughly, not just wiped over.
Who is most at risk
- Children and babies
- Pregnant women
- Older adults
- People with asthma, lung disease or heart disease
- Anyone with a weakened immune system
People in these groups should stay away from soot cleanup and out of homes with heavy soot until cleaning is finished.
Types of soot
- Dry soot: from fast, hot fires burning paper and wood. Powdery and easier to clean.
- Wet or oily soot: from slow, smoldering fires burning plastics and rubber. Sticky, smears easily and smells strongly.
- Protein residue: from burned food. Nearly invisible, greasy and very smelly.
- Fuel oil soot: from furnace puff backs. Oily and hard to clean.
Each type needs a different cleaning method, which is one reason soot cleanup often needs a professional.
If you must handle soot
- Wear a well fitting N95 respirator, gloves and eye protection
- Wear long sleeves and wash clothes afterwards
- Do not use a regular vacuum, which blows fine particles back into the air. Use a HEPA vacuum
- Lift dry soot with a dry cleaning sponge before using water
- Do not wipe soot with a wet cloth, which smears it into surfaces
- Keep the heating and cooling system off until ducts are checked
Why soot damages homes too
Soot is acidic. Left on surfaces, it can etch glass, tarnish metal, discolor grout and stain paint within days. It also corrodes electronics. That is why fire restoration companies start soot removal quickly. Read about soot removal.
Cleaning a small area of soot from a wall
- Put on an N95 respirator, gloves and eye protection.
- Open windows and cover floors and furniture.
- Vacuum loose soot with a HEPA vacuum, without touching the wall with the brush.
- Wipe with a dry cleaning sponge in straight strokes, turning the sponge as it darkens.
- Wash with a mild degreasing cleaner and rinse, working from the bottom up to avoid streaks.
- Let the wall dry fully before priming and painting.
When to call a professional
- Soot covers more than a small area
- Soot is oily or sticky, which smears easily
- Soot is inside the heating and cooling system
- Plastics, foam or electronics burned
- Anyone at home is in a higher risk group
Wildfire smoke and soot
Smoke from nearby wildfires can also leave soot and ash inside homes, even when the home did not burn. Keep windows closed on smoky days, change air filters more often, and clean ash with a HEPA vacuum and damp cloths while wearing an N95 respirator. Heavy ash inside is best left to professionals.
Quick answers: is soot dangerous
Is soot dangerous to breathe?
Yes. Fine soot particles can irritate the lungs and trigger asthma, and people with heart or lung disease are at higher risk.
Can I clean soot myself?
Small amounts, with an N95 respirator, gloves and a HEPA vacuum. Larger areas, oily soot and soot in ducts need professionals.
Is it safe to stay in a house with soot?
Not with heavy soot, especially for children, older adults and people with breathing problems, until it is cleaned.
How long does soot stay in a house?
Until it is removed. It settles on surfaces and in ducts and can keep releasing particles and odor.
Who removes soot after a fire?
A fire damage restoration company. Sifixit can connect you with a local provider.
Related
This guide covered is soot dangerous. For more background, see the National Fire Protection Association, and if you need help, Sifixit can connect you with a local provider.
This guide is general information for homeowners, not professional, insurance or safety advice for your situation.
More helpful guides
- Space heater safety: rules that prevent firesSimple rules for using space heaters safely, from the three foot rule to cords, outlets and sleeping.
- What to throw away after a house fireWhich food, medicine, cosmetics and household items to throw away after a fire, what can often be cleaned,...
- Repair or rebuild after a house fire: how the decision is madeThe decision depends on how much of the structure is damaged, whether the foundation and framing are sound,...
- Wildfire smoke damage in your home: what to doEven when a wildfire does not reach your home, smoke and ash can get inside, leaving odor, soot...
- Kitchen grease fire: what to do and what never to doTurn off the heat, then smother the flames by sliding a metal lid or baking sheet over the...
- How to prevent house fires: a room by room guideMost house fires start with cooking, heating equipment, electrical problems, smoking or candles.