The Bush Administration is drafting new rules that would bring emissions standards for off-road diesel-powered vehicles and machinery in line with rules that went into effect for on-road heavy-duty trucks last October. According to The Washington Post, the Environmental Protection Agency (EPA) and the Office of Management and Budget are proposing measures that would force engine manufacturers to install devices for capturing and treating exhaust gases and would cut off-road diesel emissions by as much as 95%, the report said. The new rules would require fuel refiners to produce diesel with a sulfur content of just 15 parts per million (ppm), down from about 3,000 ppm currently, starting in 2008. It would also make manufacturers reconfigure diesel engines starting in 2009 with more effective control devices to remove particles from exhaust. EPA assistant administrator for air and radiation Jeff Holmstead said that officials were debating two approaches on the plan's timing. The first would require refiners to reduce the sulfur content to 15 ppm by 2007. The second is a two-step approach that would call for a reduction to 500 ppm by 2007, then a further reduction to 15 ppm by 2010. Holmstead said EPA is leaning toward the two-step approach. Heavy equipment to be affected by the rules, which are scheduled to be unveiled formally by April, make up less than 5% of the U.S. vehicle fleet, but account for a disproportionately higher 30% of sulfur emissions. EPA said urban areas with heavy road construction, like Atlanta and Houston, are especially weighed down by exhaust from those sources. Though emissions standards for off-road diesel engines would become similar to those that went into effect last year for on-road diesel engines, Allen Schaeffer, executive director of the Diesel Technology Forum, said the use of engines cannot be measured. "It definitely is not an apples-to-apples comparison," Schaeffer said. "On-road diesels are moving at speeds up to 55 mph and off-road diesels aren't moving anywhere near that speed. You're not going to see a highway tractor with a blade on the front of it cutting fields, but you're also not going to see a bulldozer traveling 40 m.p.h. on the highway."