The U.S. could soon experience a severe shortage of diesel exhaust fluid (DEF), impacting U.S. drivers already hit with soaring fuel prices.

DEF is a solution made up of urea and de-ionized water that is needed for almost everything that runs on diesel. It reduces harmful gases being released into the atmosphere and works by converting nitrogen oxide produced by diesel engines into nitrogen and steam.

The solution is injected into the exhaust stream to limit pollution from diesel engines in order to meet current exhaust emissions standards.

Every diesel truck manufactured since 2010 is required to use DEF. It is also a requirement of many diesel vehicles, including trucks, tractors, buses, RVs, and private vehicles.

Due to Russian President Vladimir Putin's war against Ukraine, supplies of urea, a key ingredient in DEF, have fallen.

Russia is a major fertilizer exporter and a top exporter of urea, which is manufactured as a derivative of natural gas. Supplies, therefore, have been impacted by the war.

The global supply of urea was already being impacted by ongoing supply chain issues, but this worsened after the invasion of Ukraine on February 24.

Russia's government has also weighed suspending fertilizer and urea exports, while China, another major exporter of urea, has placed restrictions on exports.

In 2020, the U.S. imported 4.5 million metric tons of urea, coming in third behind India and Brazil.

The U.S. could be facing a shortage of diesel exhaust fluid, which is necessary for trucks manufactured after 2010. A driver fills up the tank of his car with diesel at a fuel station on May 29, 2008 in Luxembourg city.Mark Renders/Getty Images

U.S. drivers, such as Larry Miles, who works in the safety department at John Christner Trucking in Oklahoma, are already feeling the impacts of a looming DEF shortage.

"We used to spend about $500 a week on fuel, we're now spending $1,200," Miles, who has been driving a truck since 1959, told local station News on 6. "About every other fueling, you have to duel your DEF tank up."

Ashley Poole, the owner of Missouri truck repair shop Platinum Performance, told local news station KY3 that the shortage will impact diesel users with newer vehicles.

"Any Tier 4 engine or truck they can't function without it (DEF), older engines can since they're not Tier 4," said Poole.

James Marshall, an owner-operator truck driver in the state, told the news outlet that the DEF shortage will impact many truck drivers who own newer vehicle models.

Shameek Konar, CEO of Pilot Flying J—a North American chain of truck stops in the United States and Canada—said at a recent Surface Board Transportation meeting that a DEF shortage in the U.S. could sideline trucks and reduce trucking capacity, according to the High Plains Journal.

It comes at a time when fuel prices have been soaring nationwide. In a historic first, the cost of U.S. gasoline averaged more than $5 per gallon on June 11, data from AAA showed.