Is DEF Flammable? Is It Harmful For the Environment

Did you know that Diesel Exhaust Fluid (DEF) is a non-flammable substance? This means that you don’t have to worry about it catching fire.

However, it is important to understand that DEF is not completely harmless for the environment. While it helps reduce harmful emissions from diesel engines, improper handling or disposal of DEF can have negative impacts on nature.

In this guide, we will explore the flammability of DEF and its potential effects on the environment.

PropertyFlammability of DEF
Flash PointVaries depending on specific DEF
Melting PointTypically below freezing point
Potential RiskNon-flammable, low toxicity
Common UseDiesel engine exhaust treatment
UsageDiesel Exhaust Fluid (DEF) injection
Environmental ImpactReduces nitrogen oxide emissions

So, if you’ve ever wondered about the safety and environmental impact of DEF, keep reading to find out more.

Is DEF flammable?

DEF is not flammable. DEF stands for Diesel Exhaust Fluid, and it’s a non-flammable substance used in diesel engines. Its primary purpose is to reduce emissions by converting harmful nitrogen oxides into harmless nitrogen and water vapor.

The DEF fluid consists of a mixture of urea and deionized water, which is stored in a separate DEF tank in vehicles equipped with selective catalytic reduction (SCR) systems. The DEF tank is designed to be secure and leak-proof to prevent any accidental spillage.

When injected into the exhaust stream, DEF reacts with the hot exhaust gases to convert harmful pollutants into harmless substances. Therefore, DEF isn’t only non-flammable but also plays a crucial role in reducing emissions and contributing to a cleaner environment.

Is DEF Fluid Bad For Skin?

Using a small amount of DEF fluid on your skin is generally considered safe and non-harmful. DEF, or Diesel Exhaust Fluid, is a mixture of urea and deionized water that’s used in vehicles equipped with selective catalytic reduction (SCR) systems to reduce emissions of nitrogen oxides (NOx). It’s specifically designed to be safe for handling and use.

DEF fluid isn’t flammable and doesn’t pose a risk of fire or explosion. Additionally, it isn’t harmful to the environment. DEF is non-toxic and biodegradable, which means it breaks down naturally without causing harm to ecosystems.

However, it’s important to avoid prolonged or repeated skin contact with DEF, as it may cause mild irritation or dryness. If skin irritation occurs, wash the affected area with soap and water.

Does DEF fluid burn?

DEF fluid doesn’t burn. It’s a non-flammable solution that consists of 32.5% urea and 67.5% deionized water. This mixture is specifically designed to be non-combustible, ensuring safety during storage, transportation, and usage.

The non-flammability of DEF fluid is an important characteristic, as it prevents the risk of accidental fires or explosions. DEF fluid is primarily used in Selective Catalytic Reduction (SCR) systems to reduce harmful emissions from diesel engines.

Can DEF be stored alongside other chemicals?

You can store DEF alongside other chemicals without any risk of flammability or harm to the environment. DEF, or Diesel Exhaust Fluid, is a non-flammable solution that consists of 32.5% urea and 67.5% deionized water. It’s specifically designed to reduce harmful emissions from diesel engines.

Here are three reasons why DEF can be safely stored with other chemicals:

  • DEF is not flammable: Unlike many other chemicals, DEF doesn’t pose a fire hazard. It has a high flash point of approximately 122°F (50°C), meaning it doesn’t readily ignite or burn.
  • DEF isn’t harmful to the environment: DEF is a biodegradable and non-toxic fluid. It doesn’t contain any hazardous substances that can harm the environment or contaminate soil or water sources.
  • DEF can be stored in the same storage tank: DEF can be safely stored alongside other chemicals in a dedicated DEF storage tank. As long as the tank is made of compatible materials and properly labeled, there’s no risk of cross-contamination or chemical reactions.

How Flammable Is DEF Fluid?

DEF fluid has a low flammability level. This means that it isn’t easily ignited and doesn’t contribute significantly to fire hazards.

DEF, or Diesel Exhaust Fluid, is composed of a mixture of urea and deionized water. The main purpose of DEF is to reduce harmful emissions from diesel engines.

While it isn’t flammable, it’s important to handle DEF with care and avoid exposing it to open flames or high temperatures, as it may decompose and emit toxic gases.

Additionally, it’s crucial to ensure the purity of DEF, as impurities can affect its effectiveness and potentially lead to engine damage.

Therefore, using high-quality DEF, such as BlueDEF, is recommended to ensure proper DEF consumption and maintain engine performance.

What are the hazards of DEF?

Handling and exposure to DEF fluid should be done with caution due to potential hazards. Although DEF isn’t flammable, it’s important to be aware of other potential risks associated with its use. Here are the hazards of DEF:

  • Skin and eye irritation: Direct contact with DEF can cause irritation to the skin and eyes. It’s recommended to wear protective gloves and safety goggles when handling the fluid to minimize the risk of irritation.
  • Corrosiveness: DEF has the potential to corrode certain metals, such as copper and brass. It’s important to avoid contact with these materials or ensure they’re properly protected to prevent damage.
  • Contamination: Contaminating DEF with other substances, such as oil or fuel, can reduce its effectiveness. Proper storage and handling procedures should be followed to prevent contamination and maintain the quality of the fluid.

is def fluid harmful to skin?

Direct contact with DEF fluid can be harmful to your skin. DEF fluid, also known as Diesel Exhaust Fluid, is a solution composed of 32.5% urea and 67.5% deionized water.

While DEF fluid isn’t flammable, it can cause irritation and damage to the skin upon contact. The high concentration of urea in DEF fluid can act as a skin irritant, leading to redness, itching, and potential chemical burns. Continued or prolonged exposure to DEF fluid can worsen these effects and may even result in dermatitis.

It’s crucial to take necessary precautions when handling DEF fluid, such as wearing protective gloves and clothing, to minimize the risk of skin contact and potential harm.

Is It OK To Mix Different Brands of DEF?

Mixing different brands of DEF fluid isn’t recommended. While DEF fluid itself isn’t flammable or harmful for the environment, mixing different brands can lead to unpredictable reactions and potentially compromise the effectiveness of the fluid.

Here are three reasons why mixing different brands of DEF isn’t advisable:

  • Compatibility: Different brands of DEF may contain different additives or concentrations, which can result in chemical reactions that affect the performance and quality of the fluid.
  • Contamination: Mixing different brands may introduce impurities or contaminants into the DEF container, which can lead to clogging or damage to the DEF system.
  • DEF Level Monitoring: Mixing brands can impact the accuracy of DEF level monitoring systems, potentially leading to incorrect readings or malfunctions.

To ensure optimal performance and avoid any potential issues, it’s recommended to use the same brand of DEF, such as BlueDEF, consistently.

How Is DEF used?

To properly utilize DEF, it’s important to understand its application and benefits.

DEF, or Diesel Exhaust Fluid, is a non-flammable solution that’s injected into the exhaust stream of diesel engines equipped with SCR (Selective Catalytic Reduction) technology. When DEF is combined with the hot exhaust gases, it undergoes a chemical reaction that converts harmful nitrogen oxide (NOx) emissions into harmless nitrogen gas and water vapor. This process helps to reduce air pollution and meet emission standards.

DEF usage is simple and straightforward. It’s stored in a separate tank on the vehicle and is automatically injected into the exhaust system as needed. The usage of DEF isn’t harmful to the environment and doesn’t pose a fire hazard.

What Type of Hazard Is Diesel Exhaust Fluid?

You should be aware that DEF doesn’t pose any significant hazards to the environment or risks of flammability. Diesel Exhaust Fluid (DEF) is a non-flammable, non-toxic, and non-hazardous substance that’s used in Selective Catalytic Reduction (SCR) systems to reduce harmful emissions from diesel engines.

Here are three key points to understand the type of hazard DEF poses:

  • Non-Flammable: DEF is made up of 32.5% urea and 67.5% deionized water, which means it doesn’t catch fire or support combustion. This makes it safe to handle and store.
  • Non-Toxic: DEF is harmless to humans, animals, and plants. It doesn’t emit any toxic fumes or gases when used in SCR systems, ensuring the safety of the environment and those who come into contact with it.
  • Non-Hazardous: DEF has been classified as a non-hazardous substance by regulatory authorities. It doesn’t pose any significant risks to the environment, making it a safe and eco-friendly solution for reducing diesel emissions.

Mitigating Fire Hazards

First of all, you need to understand that fire hazards can be reduced by implementing effective mitigation strategies. When it comes to fire safety, it’s crucial to be proactive and take necessary precautions to prevent fires from occurring.

Here are four important strategies to mitigate fire hazards:

1. Install fire suppression systems: One of the most effective ways to combat fires is by installing fire suppression systems. These systems can quickly detect and suppress fires, minimizing the potential damage. Examples of fire suppression systems include sprinkler systems, fire extinguishers, and fire alarms. By having these systems in place, you can significantly reduce the risk of fires spreading and causing extensive damage.

2. Conduct regular inspections and maintenance: It’s essential to regularly inspect and maintain fire safety equipment to ensure its proper functioning. This includes checking fire extinguishers for expiration dates, testing smoke detectors, and inspecting electrical systems for potential fire hazards. By conducting these inspections and addressing any issues promptly, you can prevent fires from occurring due to faulty equipment or neglected maintenance.

3. Educate employees and occupants: Another crucial aspect of fire safety is educating employees and occupants about fire prevention and response techniques. Conduct regular fire safety training sessions to familiarize everyone with evacuation procedures, the use of fire extinguishers, and basic fire safety practices. By equipping individuals with the knowledge and skills to respond effectively in case of a fire, you can minimize the potential risks and ensure a safe environment for everyone.

4. Practice proper housekeeping: Maintaining a clean and organized environment is vital in mitigating fire hazards. Cluttered spaces can provide fuel for fires and hinder evacuation efforts. Encourage proper housekeeping practices, such as keeping walkways clear, storing flammable materials safely, and disposing of waste appropriately. By promoting a clean and organized workspace, you can reduce the likelihood of fires and create a safer environment for all.


Now let’s address some frequently asked questions about DEF.

One common concern is whether DEF is flammable or combustible.

Another question is whether DEF is corrosive.

Finally, there’s the issue of whether DEF is toxic.

In the following sections, we’ll provide clear and concise answers to these questions, providing you with the information you need to understand the properties of DEF and its potential impact on safety and the environment.

Is DEF flammable or combustible

DEF isn’t flammable or combustible, making it a safe and reliable solution for various applications. This is due to its chemical composition and properties. Here are three reasons why DEF isn’t flammable or combustible:

  • DEF is a mixture of urea and deionized water, which are both non-flammable substances. Urea is a stable compound that doesn’t readily ignite or support combustion.
  • DEF is primarily used in the selective catalytic reduction (SCR) process, which involves injecting DEF into the exhaust gas of diesel engines. The SCR system utilizes a catalyst to convert harmful nitrogen oxides (NOx) into nitrogen and water vapor, without the need for combustion.
  • Unlike diesel fuel, which is highly flammable, DEF isn’t used as a fuel. It’s solely used as a DEF product for reducing emissions in diesel engines.

is def corrosive

One important aspect to consider is the corrosiveness of DEF fluid. DEF, or Diesel Exhaust Fluid, is a non-flammable solution made up of 32.5% urea and 67.5% deionized water. While DEF isn’t flammable, it can still be corrosive under certain conditions.

When DEF comes into contact with certain metals such as aluminum or copper, it can cause corrosion. This is why it’s important to handle DEF carefully and avoid any spills or leaks onto metal surfaces. Corrosion caused by DEF can be harmful to the environment, as it can damage the components of a diesel vehicle’s exhaust system.

Regular maintenance and proper storage of DEF are necessary to prevent any potential corrosive effects and ensure the longevity of the vehicle’s exhaust system.

is def toxic

When handling DEF, it’s important to be aware of whether or not it’s toxic. Here are some important points to consider:

  • DEF, or Diesel Exhaust Fluid, isn’t toxic. It’s a solution consisting of urea and deionized water, and it’s specifically designed for use in diesel engines to reduce nitrogen oxide (NOx) emissions.
  • Urea, the main component of DEF, is a non-toxic compound commonly found in fertilizers and pharmaceuticals. It’s safe to handle and poses no harm to the environment.
  • When DEF is injected into the exhaust stream of a diesel engine, it reacts with the NOx emissions, converting them into harmless nitrogen and water vapor. This process helps to reduce air pollution and improve air quality.


In conclusion, DEF fluid isn’t flammable and doesn’t pose a risk to the environment. It’s safe to store alongside other chemicals and can be used in various applications.

One interesting statistic is that DEF fluid is approximately 32.5% urea, which helps reduce nitrogen oxide emissions from diesel engines by up to 90%. This visual representation demonstrates the effectiveness of DEF in reducing harmful pollutants.

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karl-rock fire fighter

Karl Rock

Hey there, I'm Karl Rock, a dedicated firefighter with a passion for safety. Through my blog, I'm here to share crucial insights about the nature of flammability and effective ways to safeguard both lives and homes. With years of experience on the frontlines, I'll bring you valuable tips and knowledge to help you understand fire's behavior and how to prevent its devastating impact. Join me on this journey to empower yourself with life-saving information and create a safer environment for you and your loved ones. Together, we'll conquer the flames and ensure a secure future.

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