What is Diesel Exhaust Fluid

Diesel Exhaust Fluid (DEF) is a non-toxic, high purity solution comprised of 32.5% urea and 67.5% de-ionized water. 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. A new set of gauges will be located on your vehicle’s dashboard, much like the diesel gauge, to let you know when your truck needs refilling. Refilling is similar to refueling diesel and can be done at all major truck stops across North America.

Reducing Emissions Emitted by Diesel Engines

Diesel Exhaust Fluid is produced to an international standard (ISO 22241). To meet 2010 EPA Diesel Emission Standards to reduce the amount of NOx emitted by diesel engines, several engine manufactures employed Selective Catalytic Reduction (SCR) as an after-treatment technology combined with Exhaust Gas Recirculation (EGR).

The combination of SCR and DEF reduces particulate matter emissions by breaking down NOx into harmless nitrogen and water molecules. With the use of DEF, 2.6 million tons of smog-causing NOx emissions will be reduced yearly.

EPA Emissions Standards

In 2000, the Environmental Protection Agency (EPA) proceeded with its rule to make heavy-duty on-road equipment, such as trucks and buses, run cleaner with the ‘ 2007 Highway Rule’. According to the EPA, “Beginning with the 2007 model year, the harmful pollution from heavy-duty highway vehicles will be reduced by more than 90%.”

For 2010, the US EPA requires diesel truck emissions contain a 97% reduction in their sulfur content. Engine manufacturers have come up with two advanced pollution control technology options for cars, trucks, and buses which include Selective Catalytic Reduction (SCR) and Exhaust Gas Recirculation (EGR).

Selective Catalytic Reduction (SCR) Technology

Selective Catalytic Reduction

Selective Catalytic Reduction (SCR) is an exhaust after treatment system that injects a small amount of Diesel Exhaust Fluid (DEF) into the exhaust.

DEF is mixed with the exhaust in the presence of a catalyst turning NOx (oxides of nitrogen – a harmful pollutant that contributes to smog and acid rain) into innocent nitrogen and water vapor.

Exhaust Gas Recirculation

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.

Most major diesel truck manufacturers have opted to use SCR technology to meet the EPA emissions standards for NOx reduction. SCR is a cost effective solution and provides the following advantages for your company:

  • Better fuel economy for your fleet
  • Improves engine lubrication and filter life
  • Meets 2010 vehicle emission standards for diesel engines

Your SCR system requires high quality Diesel Exhaust Fluid to run efficiently. Make sure you are purchasing product from a reputable distributor to prevent contamination from damaging your diesel vehicles.

American Petroleum Institute (API) Logo

API Certification

The American Petroleum Institute (API) is the only national trade organization that certifies the quality of DEF to international standards and licenses manufacturers who consistently meet these standards set by the International Organization for Standardization (ISO).

The API Diesel Exhaust Fluid Certification Program is a voluntary program designed to certify and monitor DEF quality. API issues a seal to those manufacturers who are committed to quality and meet specific performance requirements. UltraPure® DEF is certified by API and proudly displays their seal on our packaging.

What this means to our customers:

  • Provides rigorous monitoring of fluids in the marketplace
  • Identifies brands meeting diesel engine manufacturer requirements
  • Helps consumers easily recognize those brands


We provide API Certified Diesel Exhaust Fluid (DEF) to customers, distributors, and dealerships throughout North American for every market segment.

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Package Sizes


UltraPure Diesel Exhaust Fluid comes in a variety of package sizes including 2.5 Gallon Jugs, 55 Gallon Drums, 330 Gallon Totes, Mini-Bulk and Bulk.

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Equipment Solutions


We partner with various elite equipment manufacturers in the Diesel Exhaust Fluid industry to provide our customers with solutions that meet their needs.

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Case Studies

Case Studies

Are you having trouble with your current Diesel Exhaust Fluid supplier? Are you ineterested in learning how we've helped other companies in a similar situation? Read our case studies to find out how!

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