The History of Diesel Exhaust Fluid

25 Apr 2018, Posted by McPherson Oil in Oil Tips

Since the Clean Air Act was put in to place in the 1970s, the Environmental Protection Agency (EPA) has been making strides toward lowering emissions. Trucks using commercial fuel services have recently been under tighter regulations when it comes to this environmental threat. In response, modern, diesel engines are required to use diesel exhaust fluid (DEF) in effort to reduce harmful emissions.

Here is a quick rundown of how DEF came to be and what you need to know about it.

When Commercial Fuel Services Started Including DEF

For years, truck drivers and fleet managers didn’t have to worry about smog-proof equipment on their vehicles. Come 2008, the EPA mandated that all three-quarter-ton and larger trucks had diesel particulate filters installed.

Then, the EPA tightened the restrictions even more in 2010. The agency required medium- and heavy-duty vehicles to step it up a notch by reducing engine emissions, especially for NOx and particular matter (PM) by incorporating DEF.

Why the EPA Changed Regulations for Commercial Trucks

The purpose of these new regulations was to ultimately improve air quality. NOx and PM are linked to respiratory and cardiovascular diseases, as well as asthma, acute respiratory symptoms, chronic bronchitis, and decreased lung function.

The agency predicts that these changes will prevent 8,300 premature deaths, greater than 9,500 hospitalizations, and 1.5 million lost work days due to sickness. This comes to a total savings of $70.3 billion by 2030.

The Technology Behind DEF

When owners were forced to install smog equipment on their heavy-duty trucks, owners thought the days of power and torque were over. The work-around was the use of Selective Catalytic Reduction (SCR) technology.

This approach is known as an “after treatment” since it eliminates dangerous emissions after combustion. DEF is sprayed in to the exhaust stream, breaking down the harmful NOx into simple nitrogen and water. The good news is that this after-the-fact treatment still leaves the door open for manufacturers to build in as much power as owners desire.

Where Drivers Can Purchase DEF

Most truck stops, dealers, aftermarket parts stores, and other outlets that provide commercial fuel services carry DEF for purchase. Drivers have the option to buy a 1- or 2.5-gallon jug for their vehicle, with thousands of truck stops offering DEF at the fuel island. Among the leaders are Pilot Flying J, followed by Love’s, and TravelCenters of America. Some fleet managers find it’s best for them to provide 55-gallon drums, 275-gallon or 330-gallon totes on site, which can save money in the long run.

If you’re ready to get the best deals on DEF for your fleet, get in touch with McPherson Oil. Our DEF specialists can streamline your fleet, save you money, and lower your insurance exposure with a master plan for your Diesel Exhaust Fluid and SCR systems. Call us at 1-888-802-7500 or email us at

About: McPherson Oil is proud to distribute ExxonMobil products in the southeast including Alabama, Arkansas, Florida Panhandle, Georgia, Louisiana, Mississippi and Tennessee.