This month, refiners must begin producing low-sulfur diesel fuel for use in off-road (i.e., nonroad) diesel equipment, including construction equipment.
Starting June 1, refineries must reduce sulfur in off-road diesel fuel from current levels of about 3,400 parts per million (ppm) to a maximum of 500 ppm (with few exceptions), as required by a clean-air regulation set by the U.S. Environmental Protection Agency (EPA) back in 2004.
This is the first step of EPA's so-called "Nonroad Diesel Rule." That rule also requires sulfur levels in most off-road diesel fuel to be dropped to 15 ppm by 2010. That's a 99 percent reduction from current levels. The lower sulfur content is expected to allow the application of advanced emissions control technologies that should substantially lower emissions of pollution from diesel engines.
One year ago - in June 2006 - separate EPA rules took effect requiring 80 percent of highway diesel fuel to have an ultra-low sulfur level of no more than 15 ppm. All highway diesel must be ultra-low sulfur diesel (ULSD) by 2010.
The 500 ppm diesel will remain available in diminishing quantities until 2010. EPA estimates the cost of diesel fuel will increase by at least five cents per gallon, due to expenses incurred by petroleum producers.
In California, all diesel fuel has already made the transition to 15 ppm sulfur.
