On June 1, oil refiners are scheduled to start producing low-sulfur diesel for off-road use, instead of the high-sulfur fuel that’s been used in the past.
Low-sulfur diesel – the norm up until last year for on-highway use – has a sulfur content of 500 ppm.
The red-dye diesel previously used for off-highway use in tractors and other machinery has up to 3,000 parts per million sulfur content. Off-highway equipment includes motors in reefer units or auxiliary power units.
By 2010, the U.S. Environmental Protection Agency plans to require that off-road diesel be ultra-low sulfur diesel – the same type currently being used in trucks.
Diesel with high sulfur content will be phased out completely by 2010 for most applications, with the exception of trains and motor boats, in which case refiners have until 2012 to make the switch.