• 500 ppm: Refers to a sulfur limit of 500 ppm = 0.05% (wt.). 500 ppm diesel fuel is referred to as Low Sulfur Diesel Fuel, and was introduced in October of 1993. Low Sulfur Diesel Fuel was introduced to facilitate reductions in particulate emissions, necessary to meet 1994 emissions standards.
• 15 ppm: Refers to a sulfur limit of 15 ppm = .0015% (wt). 15 ppm diesel fuel is referred to as Ultra Low Sulfur Diesel Fuel (ULSD), and will be blended beginning in June of 2006, available for use beginning in October 2006.

• 500ppm: The 500ppm diesel mandate will be effective June 1st 2007 for non-road, locomotive and marine diesel fuels.
• 15ppm (ULSD): The 15ppm diesel mandate will be effective June 1st 2010 for non-road diesel fuel and June 1st 2012 for locomotive and marine diesel fuels.

The EPA has mandated the regulations for sulfur content in non-road diesel fuels, to allow emissions control technologies, such as particulate filters and NOX adsorbers to be utilized.

• 15ppm (ULSD): Effective June 2006, the sulfur specification in CARB diesel was lowered to 15 ppm or 0.0015% (wt.) in harmonization with the federal regulations for on-highway diesel fuel.

CARB mandated that by September 1st, 2006, ULSD will be the only type of diesel fuel legal for use with on-highway and non-road applications (except 500 ppm fuel may still be used in locomotives and marine diesel engines).

Kubota believes that even with 500 ppm diesel fuel available for non-road use, the potential exists for customers to use ULSD in Kubota engines.

1. Kubota, through engine testing, has not experienced fuel system component failure related to the use of 15 ppm sulfur ULSD.
2. Kubota recommends the use of diesel fuel that is refined to appropriate on-highway and off-highway standards.
   1. Kubota cannot be responsible for any fuel system component failures due to inappropriate fuel, incorrect lubricity or fuel additives used.
   2. Appropriate diesel fuel standards include ASTM D975 for lubricity. D975 is a standard that was adopted in 2005 to manage the concern of decreased lubricity as sulfur is removed from diesel fuel.
3. Kubota is not responsible for loss of power or increase in fuel consumption that could result from the use of ULSD.
   1. According to various sources, a reduction in energy content on the order of 1 – 2% can be expected. This may have a corresponding negative affect on peak power available.
4. This position is in accordance with Kubota Engine America Service Policy and Warranty Statement dated September 2, 1997.