Frequently Asked Questions

Diesel Exhaust Fluid (DEF) is a non-toxic, high purity solution comprised of 32.5% urea and 67.5% de-ionized water for specific use in Selective Catalytic Reduction (SCR) systems. Using this fluid in diesel-powered vehicles, such as trucks, buses, and tractors, helps to reduce the amount of nitrogen oxides (NOx) emitted into the air by 90%.

It is not a fuel additive and must be filled into the dedicated Diesel Exhaust Fluid tank on your diesel vehicle.

The active ingredient in Diesel Exhaust Fluid (DEF) is urea. Urea producers supply two types of urea, automotive grade and agricultural grade. Automotive grade urea, unlike urea used in fertilizers, does not contain formaldehyde and must be used in the production of DEF. Formaldehyde and other impurities can cause damage to the catalyst in your Selective Catalytic Reduction (SCR) system.

Urea is created from synthetic ammonia and carbon dioxide. When subjected to high heat and pressure it can be produced as a liquid or a solid. Synthetic urea is used mainly in fertilizers, but is also used in plastics, animal feed, cleaning agents, and pharmaceutical applications.

Many diesel engine manufacturers have chosen Selective Catalytic Reduction (SCR) technology to meet the 2010 EPA Emissions Standards. Diesel Exhaust Fluid is used in the SCR system for on-road diesel vehicles manufactured beginning in 2010. Without DEF, your diesel vehicles will not function.

SCR and DEF are used to convert Nitrogen Oxide (NOx) into harmless Nitrogen and Water molecules. Nitrogen makes up about 78% of the air we breathe.

Selective Catalytic Reduction (SCR) is an exhaust after treatment system that injects a small amount of a chemical called Diesel Exhaust Fluid (DEF) into the exhaust. DEF is mixed with exhaust in the presence of a catalyst turning NOx (oxides of nitrogen – a harmful pollutant that contributes to smog and acid rain) into harmless nitrogen and water vapor.

This technology has the ability to reduce NOx to near zero levels while also providing your fleet with a 3-5% savings on diesel fuel usage.

Selective Catalytic Reduction (SCR) is designed to permit nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called "selective" because it reduces levels of NOx using ammonia as a reluctant within a catalyst system.

The reducing agent reacts with NOx to convert the pollutants into nitrogen, water and tiny amounts of carbon dioxide (CO2) - natural elements common to the air we breathe every day. The reluctant source is usually automotive-grade urea, otherwise known as Diesel Exhaust Fluid, which can be rapidly hydrolyzed to produce the oxidizing ammonia in the exhaust stream. SCR technology alone can achieve NOx reductions in excess of 90%.

Selective Catalytic Reduction (SCR) is an exhaust after treatment system that injects a small amount of a chemical called Diesel Exhaust Fluid (DEF) into the exhaust. DEF is mixed with exhaust in the presence of a catalyst turning NOx (oxides of nitrogen – a harmful pollutant that contributes to smog and acid rain) into harmless nitrogen and water vapor.

Exhaust Gas Recirculation (EGR) is another way to reduce NOx formation. In an EGR system, engine exhaust is recycled back through the engine to dilute the oxygen. Almost all engine manufacturers’ use a form of EGR, as it takes both EGR and SCR to achieve near-zero NOx emissions.

The use of Selective Catalytic Reduction (SCR) technology and Diesel Exhaust Fluid has the ability to reduce NOx emissions to near zero levels while also providing your fleet with a 3-5% savings on diesel fuel usage.

Selective Catalytic Reduction (SCR) has been implemented by several leading original truck producers (also referred to as OEM’s) such as:

  • Peterbilt
  • Kenworth
  • Freightliner
  • Ford
  • Daimler
  • Hino
  • Volvo
  • Mack Trucks North America

Diesel Exhaust Fluid is sold at a variety of car and truck dealerships, truck stops, retail, and convenience store locations across North America.

Fueling your vehicles at home is more cost effective than purchasing product from these locations. If you are interested in purchasing DEF, please request a quote, call our toll free number at 1-877-363-5843, or email us at .

Diesel Exhaust Fluid varies in price across the country, much like diesel fuel. Other factors affecting price include:

  • Ammonia, Oil, and/or Natural Gas Costs
  • Package Size
  • Order Quantity

If you are interested in purchasing DEF, please request a quote, call our toll free number at 1-877-363-5843, or email us at .

We offer Diesel Exhaust Fluid in a variety of package sizes - 2.5 Gallon Jugs, 55 Gallons Drums, 330 Gallon Totes, mini-bulk, and bulk.

We offer two different types of totes: one-way returnable and refillable.

  • Returnable Diesel Exhaust Fluid totes can be returned and refilled as long as there has been no contamination.
  • Refillable on-site totes can be left at your location and will be refilled by a Brenntag delivery truck.

Contact your local DEF sales representative to learn about our program to pick up competitor’s empty totes to replace them with UltraPure filled totes.

Yes, quality of Diesel Exhaust Fluid is extremely important. High quality DEF will be produced and distributed by companies that have demonstrated their domestic expertise in production and distribution. The qualified companies will bear the American Petroleum Institute (API) Certified symbol.

Check out why quality matters with Diesel Exhaust Fluid here.

The American Petroleum Institute (API) Certification program authorizes Diesel Exhaust Fluid distributors that meet specified requirements to use the API Certified symbol. This mark identifies which distributors meet the ISO performance requirements.

This program provides the following benefits to consumers:

  • Provides rigorous monitoring of fluids in the marketplace.
  • Tests licensed fluids to ensure they meet program requirements.
  • Identifies brands that meet diesel engine manufacturer requirements.
  • Helps reduce NOx emissions.

Yes, Diesel Exhaust Fluid has a harmless mild odor due to the ammonia content.

One gallon of Diesel Exhaust Fluid weighs 9.08lbs.

  • Hazardous? - No, Diesel Exhaust Fluid is classified as a non-hazardous material.
  • Corrosive? - Diesel Exhaust Fluid is corrosive to most metals. Stainless steel is the only metal used in manufacturing DEF pump equipment.
  • Flammable? - Diesel Exhaust Fluid is not flammable as classified by WHMIS/OSHA criteria. In case of a fire, DEF containers may be extinguished with water.

Read more about DEF handling in our DEF DO's and DON'Ts here.

Small spills may be absorbed with a non-reactive absorbent and placed in suitable, covered and labeled containers. Prevent large spills from entering into waterways, sewers, basements, or confined areas. DEF can be harmful to concrete and masonry. Never return spills back into the original containers for re-use.

Spilled Diesel Exhaust Fluid should be cleaned up as soon as possible.

ISO22241 recommends Diesel Exhaust Fluid (DEF) should be stored in a cool, dry place. Ideal storage temperatures should be between 12°F (11°C) and 86°F (30°C). The reason of this recommendation is due to the fact DEF can lose its potency if stored above 86°F for prolonged periods of time.

We can assist you in developing equipment storage solutions to ensure your product is best preserved in all weather conditions.

Read more about Summer Storage and Handling DEF in Cold Climates.

Diesel Exhaust Fluid should be stored out of direct sunlight in a cool, dry and well-ventilated area. Ideal storage temperatures are between 12° F (11° C) and 86° F (30° C). Optimum storage facilities include garages, warehouses or storage systems recommended by equipment manufactures.

If you have any questions regarding proper storage, contact us today.

Diesel Exhaust Fluid has unique properties making it crucial to use the proper equipment. DEF is stored and dispensed through dedicated containers and systems. We can assist you in developing equipment storage solutions to meet your specific needs.

Diesel vehicles are equipped with heated tanks and supply lines designed to freeze and thaw with no performance issues.

Diesel Exhaust Fluid will remain unharmed if it freezes and thaws. The urea and water will not separate or lose its potency.

No, Diesel Exhaust Fluid is not a diesel additive. Vehicles manufactured with Selective Catalytic Reduction (SCR) technology are designed with a separate urea tank to hold Diesel Exhaust Fluid. Do NOT mix DEF and diesel fuel.

Read more about DEF in the Diesel Tank here.

If a non-DEF substance enters the Diesel Exhaust Fluid tank, the Selective Catalytic Reduction (SCR) system will recognize a substance other than DEF. The trucks indicator light will then turn on to notify the driver. Whether or not the vehicle requires servicing is dependent on the level of contamination.

Standard diesel fuel nozzles have a diameter of 22mm. Diesel Exhaust Fluid nozzles have been manufactured at 19mm to prevent standard nozzles from being placed into the DEF tank opening. The DEF tank is also easily recognizable due to its blue tank cap.

The amount of Diesel Exhaust Fluid your truck will use is dependent on the size of the truck’s tank and dosing rate chosen by the vehicle manufacturer. DEF tanks range in size from approximately 6 to 30 gallons.

The chart below can be used to determine your usage. Use our interactive Diesel Exhaust Fluid calculator for more accurate results.

Refueling intervals will depend on the size of your tank. The Diesel Exhaust Fluid consumption rate is between 2-4% of the diesel fuel consumption.

For example, for every 100 gallons of diesel fuel consumed, between 2-4 gallons of DEF will automatically be injected into the exhaust system. A typical diesel truck can go about 300 miles on one gallon of Diesel Exhaust Fluid.

A typical diesel truck could go about 300 miles on one gallon of Diesel Exhaust Fluid.

If your vehicle runs out of DEF, you will first experience performance degradation followed by the inability to start the vehicle.