BlueDEF® is a premium Diesel Exhaust Fluid (DEF) engineered to reduce harmful emissions and support optimal performance in diesel engines equipped with Selective Catalytic Reduction (SCR) systems. Trusted by professionals across transportation, agriculture, and construction industries, BlueDEF helps meet EPA standards by converting harmful nitrogen oxide (NOx) emissions into harmless nitrogen and water vapor. Produced by Old World Industries, the makers of other trusted brands like PEAK®, BlueDEF is manufactured under strict quality standards to ensure purity, consistency, and compatibility with all SCR systems. Whether you're managing a fleet or maintaining a single diesel vehicle, BlueDEF is the go-to choice for reliable DEF performance.