Can you use 10 year old kerosene?

Quick Answer

Kerosene that is 10 years old may still be usable, but it’s best to test it first. Over time, kerosene can degrade, absorb water, and grow bacteria. Old kerosene may not burn as well or efficiently as fresh kerosene. The best way to test old kerosene is to try burning a small amount. If it burns fine, with no unusual smells or smoke, then the kerosene should still be good to use. However, if it doesn’t burn well, it’s best to dispose of it safely and get fresh kerosene. Using old, degraded kerosene in heaters, lamps, or other appliances can clog parts, produce toxic fumes, and be a fire hazard.

Does Kerosene Go Bad?

Yes, kerosene can eventually go bad or degrade in quality if it is stored for too long. Here are some key factors that can cause kerosene to degrade over time:

  • Oxidation – Exposure to oxygen in the air can cause kerosene molecules to break down over time.
  • Contamination – Kerosene can become contaminated by water, dirt, debris, bacteria, or fungi, especially if stored in containers that are not air-tight.
  • Evaporation – Lighter compounds in kerosene can evaporate over time, altering its combustion properties.
  • Polymerization – The hydrocarbon molecules in kerosene can link together into larger, heavier molecules that don’t burn as well.

In general, kerosene that is stored properly in sealed, air-tight containers away from heat and sunlight can last up to 10 years before going bad. However, degraded kerosene may start to take on some of these signs:

  • Cloudy or dark appearance
  • Strange odors like rotten eggs or fungus
  • Increase in viscosity or thickness
  • Discoloration or formation of sludge
  • Separation into distinct oil and water layers

If your kerosene exhibits any of these properties, it’s a sign that it has likely gone bad and should not be used.

Does Old Kerosene Expire?

Kerosene itself does not have a defined expiration date. Because it is a hydrocarbon fuel, kerosene can remain chemically stable for many years when stored properly. However, kerosene will gradually degrade in quality and usability over time due to factors like oxidation, evaporation, moisture, and bacterial growth.

Most industry sources estimate kerosene will keep its properties and performance for about 10 years when stored in ideal conditions in sealed containers designed for fuels. However, once kerosene is about 10 years old, it is at much higher risk of being expired or unusable.

Testing is the only surefire way to determine if old kerosene is still good or expired. Trying to burn a small sample is an effective test. If very old kerosene burns poorly or gives off foul odors, it should be disposed of and fresh kerosene should be purchased instead. While an exact expiration date can’t be pinned down, once degradation becomes apparent, that kerosene should be considered expired and unsafe to use.

Does Kerosene Go Bad if it Smells?

Yes, a bad or strange odor in kerosene is a definitive sign it has gone bad and should not be used. Fresh, high-quality kerosene should have a mild oily or hydrocarbon smell similar to gasoline or mineral spirits.

Some common off-odors that can develop in old, degraded kerosene include:

  • Rotten eggs or sulfur smell – This indicates mercaptans or sulfurous compounds have formed, which can clog fuel lines and burn poorly.
  • Decaying vegetation or swampy smell – This can signal the growth of anaerobic bacteria that produce foul organic acids.
  • Rancid or paint-like smell – This points to oxidation of the fuel into unstable peroxides over time.
  • Moldy or musty smell – This means fungi have grown in the kerosene, breaking down the fuel.

Any kerosene with these telltale smells should not be used, as it will likely burn dirty or degrade equipment. The odors indicate excessive contamination or chemical breakdown. The kerosene should be safely disposed of and fresh kerosene purchased.

How to Test if Old Kerosene is Still Good

Here are some recommended methods to test if old kerosene is still good to use:

Visual Inspection

Inspect the kerosene in good light. It should appear clear or straw-colored. Cloudiness, darkening, or layer separation signals contamination and degradation.

Odor Test

Take a whiff of the kerosene. It should have a mild oily or hydrocarbon odor without any harsh, acidic, or rotten smells. Strange odors indicate microbes, oxidation, or chemicals forming.

Burn Test

Try burning a small amount of the kerosene (safely, outdoors). Good kerosene should burn steadily with a bright hot flame and minimal smoke or odor. Poor combustion can mean expired fuel.

Evaporation Test

Pour a teaspoon of kerosene onto a paper towel and allow it to evaporate fully. Fresh kerosene will leave no residue. Large darkened stains signal contaminants and soluble aged particles.

Viscosity Test

Swirl the kerosene. It should move fluidly like water. Thick, syrupy kerosene shows polymerization of the hydrocarbons into heavier compounds.

Mixing Test

Mix a few teaspoons of kerosene into one cup of water. Good kerosene will float on top with minimal dispersion. Bad kerosene will emulsify or sink, indicating contamination.

Is it Safe to Use 10 Year Old Kerosene?

Using 10 year old kerosene may be safe, provided it has been properly stored and passes testing to verify it is still good. Kerosene that has been kept from the elements in sealed, air-tight containers has the best chance of remaining usable for that period of time.

However, 10 years is towards the maximum viable storage time for kerosene. Over that timeframe, even stored kerosene can start to oxidize, evaporate, absorb moisture, separate, and allow microbial growth. These degrade the combustion properties and increase the risk of issues.

It is not automatically unsafe to use kerosene that is 10 years old. But it does have a higher risk of performance problems. Before using, it is highly recommended to test the kerosene by methods like a visual inspection, smell test, evaporation test, or burn test. If it fails these tests, it should not be used and should be disposed of properly instead.

With appropriate testing and storage, using 10 year old kerosene could be safe. But there is a good chance degradation has started, so fresh kerosene is generally recommended whenever possible.

How to Revitalize Old Kerosene

If you have old kerosene that doesn’t burn well or fails testing, there are a few methods you can try to potentially revitalize it:

  • Filter – Passing the kerosene through a fine filter can remove many contaminants and debris.
  • Distill – Boiling off and re-condensing the kerosene separates lighter, better burning fractions.
  • Air Dry – Letting kerosene sit open to the air for 1-2 days allows some volatile compounds to evaporate.
  • Mixing – Blending old kerosene 50/50 with fresh kerosene can improve properties.
  • Additives – Fuel stabilizers, biocides, or corrosion inhibitors can counteract some degradation issues.

However, these are not guaranteed solutions, and severely contaminated or degraded kerosene may still be unusable and require proper disposal. Whenever possible, it is best to start with fresh kerosene rather than trying to salvage very old product of questionable quality.

Signs Kerosene Has Gone Bad

Here are some clear signs that stored kerosene has spoiled and should not be used:

  • Cloudy appearance or has particles/debris floating in it
  • Darkened color from light straw to reddish brown
  • Strong odor like rotten eggs, swampy, rancid, or moldy
  • Thick, syrupy viscosity rather than flowing freely like water
  • Poor, smoky burn quality with yellow flames
  • Separated into distinct oil and water layers
  • Growth of black or greenish mold/algae/bacteria
  • Corroded, rusted, or damaged storage container

Kerosene with any of these defects should be disposed of properly. Trying to filter or revitalize kerosene with extensive contamination or biological growth may not be successful and poses safety risks. If kerosene exhibits multiple signs of spoiled quality, it is best to discard it.

How to Dispose of Bad Kerosene

To safely dispose of kerosene that has gone bad:

  • Wear gloves, eye protection, and a respirator mask when handling.
  • Transfer to approved fuel storage containers specifically marked for waste fuel.
  • Contact your local municipal household hazardous waste collection center to arrange dropping off bad kerosene. Many will accept small volumes of household fuels.
  • For larger amounts, contact a commercial hazardous waste disposal company to handle bad kerosene.
  • Never pour kerosene down drains, into storm sewers, onto the ground, or into regular trash.
  • Allow rags or absorbents soaked with kerosene to fully air dry outdoors before disposal to reduce fire risks.
  • Check for any local regulations that may restrict kerosene disposal in your area.

Following safe handling and waste disposal guidelines is important when getting rid of spoiled kerosene. This helps avoid pollution, dangers from inhalation or skin exposure, and potential fines for improper disposal.


Old kerosene that is 10 years or older could potentially still be usable if it was stored properly in sealed containers away from heat and oxygen. However, it has an elevated risk of going bad or becoming contaminated over that timeframe. Before using very old kerosene, it is highly recommended to test it through methods like visual inspection, odor test, burn test, mixing test, or evaporation test. If the kerosene has an off appearance, smell, viscosity, burn quality, or separation, it should not be used and should instead be disposed of safely. While 10 year old kerosene can possibly be used after testing, it runs a greater chance of performance issues compared to fresh kerosene. Whenever possible, it is generally best to use kerosene that is less than 10 years old to ensure optimal quality and safety. Proper storage, limiting exposure to air and moisture, using fuel stabilizers, and filtering can help prolong the usable life of kerosene. But kerosene that shows multiple clear signs of spoilage like odor, cloudiness, or poor combustion should be discarded through approved hazardous waste collection. Using degraded kerosene can be risky, while disposing of it safely protects health and the environment.

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