The U.S. national average for bulk diesel exhaust FLid prices remained stable for less-than-truckload and tote refill delivery modes, while full truckload deliveries posted a 6 cents per gallon average price increase.

Commodity data provider Integer Research also said Canadian DEF bulk prices followed a different trend and decreased across all supply formats, according to its DEF Tracker.

While U.S. national truck stop prices have remained stable for the second consecutive month, the Canadian national average price at truck stops moved back to CA$0.80 per liter after settling at CA$0.81 during the past two months.

A month-to-month increase in prices was observed for 2.5 gallon jugs, with the U.S. national average price shifting upwards by 6 cents per gallon to $5.88 per gallon in June.

The highest average prices for bulk delivery modes were found in Phoenix and San Francisco. On the other hand, the lowest averages were found in Atlanta, Cincinnati and Houston.

Diesel exhaust fluid is required in most 2010 and later model truck engines in order to meet federal emissions requirements.