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White, Grey and Black Smoke: What's the Difference?

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When it comes to fires, not all smoke is created equal. In fact, the type of smoke produced by a fire can give you valuable information about what is burning and how hot the fire is.

The main difference between white, gray, and black smoke from a fire lies in the type of products burned, the size, and the danger of the fire.

Here's a quick guide to the three main types of smoke you might see coming from a fire.

White Smoke

white smoke
White smoke coming from a chimney

The first and most common type of smoke is white smoke. This smoke is produced when paper, wood, or other organic materials are burned slowly with little oxygen. White smoke is usually thin and easy to see through. If you see white smoke coming from a fire, it's a good indication that the fire is still relatively small and manageable.

Grey Smoke

grey smoke
Grey smoke in a wildfire

The second type of smoke is grey smoke. Grey smoke is produced when plastics or other synthetic materials are burned. This type of smoke is usually thicker and darker than white smoke. If you see grey smoke billowing from a fire, it's an indication that the fire is getting larger and more out of control.

Black Smoke

black smoke
Black smoke plastic fire in Golden State

The last and most dangerous type of smoke is black smoke. Black smoke is produced when petroleum products like gasoline or oil are burned. This type of smoke is very thick and dark, making it difficult to see through. If you see black smoke coming from a fire, it's an indication that the fire is large and out of control—and you should evacuate immediately!

Differences between White, Grey, and Black Smoke

Size of the Fire

The type of smoke produced depends on the size of the fire. A small fire produces white smoke, while a larger fire produces grey or black smoke.

One difference between white and grey smoke is the level of oxygen available to the fire. White smoke occurs when there is plenty of oxygen, while grey smoke occurs when there is less oxygen. Black smoke occurs when there is very little oxygen.

The amount of oxygen available to a fire determines how hot it will burn. A small fire will not be as hot as a large fire, so it will not produce as much smoke.

Type of Products Burned

The type of smoke that is produced depends on what is being burned. When wood, paper, or other organic materials are burned, it creates white smoke. This happens because this type of combustion produces carbon dioxide and water vapor.

Grey smoke is produced when something that contains a lot of sulfur is burned. Sulfur is found in things like coal, oil, rubber, and plastics. When these materials are burned, they create a grey smoke that can be very harmful to breathe in.

Black smoke is produced when petroleum products are burned. This happens because the combustion of petroleum products produces carbon dioxide, water vapor, and soot (a mix of solid particles and liquids). Soot is black in color and gives black smoke its characteristic color.


In general, white smoke is not as dangerous as black smoke because it is not as dense and does not contain as many harmful chemicals. However, each situation is different and grey smoke can be either dangerous or not depending on the circumstances. If you are ever unsure, it is always best to err on the side of caution and seek medical help.

Comparison Table: White Vs Grey Vs Black Smoke

SpecificationsWhite smokeGrey smokeBlack smoke
Size of the fireSmallLargeVery large
Type of products burnedWood, paper, or other organic materialsSulfur-based substances: coal, oil, rubber, and plasticsPetroleum products
DangerLess dangerousDangerousVery dangerous

Frequently Asked Questions

Is black smoke dangerous?

Yes, black smoke can be dangerous. It can contain high levels of carbon monoxide and other harmful chemicals. If you are exposed to black smoke, it is important to get to fresh air as soon as possible and seek medical attention if needed.

What is carbon monoxide?

Carbon monoxide (CO) is a colorless, odorless gas that can be deadly if inhaled. It is produced when fuels such as natural gas, propane, oil, wood, and coal are burned. CO from these sources can build up in enclosed or poorly ventilated spaces and lead to serious health effects or even death.

How can you tell that there is a fire in your home?

There are a few telltale signs that there may be a fire in your home. First, you will likely see and smell smoke. You may also see flames, or feel heat coming from a particular area. If you hear a loud banging or popping noise, this could also indicate that there is a fire. If you notice any of these signs, it is important to evacuate the premises immediately and call 911.


Smoke from a fire can tell you a lot about what's burning and how hot the fire is. The next time you see a fire, take note of the type of smoke it's producing. If it's white smoke, the fire is small and manageable. If it's grey smoke, the fire is getting larger and more out of control. And if it's black smoke, the fire is large and out of control—so get to safety immediately!

Feel free to comment and discuss about the article in the comment space below if you have any information or remarks to add. If you think we made a mistake, you can also report it there.
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About the Author: Nicolas Seignette

Nicolas Seignette, who holds a scientific baccalaureate, began his studies in mathematics and computer science applied to human and social sciences (MIASHS). He then continued his university studies with a DEUST WMI (Webmaster and Internet professions) at the University of Limoges before finishing his course with a professional license specialized in the IT professions. On 10Differences, he is in charge of the research and the writing of the articles concerning technology, sciences and mathematics.
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