This week marked a major milestone for the nation’s transition to ultra-low sulfur diesel (ULSD) fuel as all highway diesel fuel in the United States complies with the landmark 15 parts per million (ppm) sulfur standard – a 97 percent reduction in sulfur content from diesel’s 2006 levels.

The Dec. 1, 2010 deadline was mandated by the Environmental Protection Agency (EPA). However, according to EPA’s pump survey, the highway transition to ULSD was actually completed a few weeks ago. The EPA pump survey results are available.

“It is quite a remarkable feat that refiners have been able to reduce the sulfur content in diesel fuel by 97 percent,” said Allen Schaeffer, the executive director of the Diesel Technology Forum. “The United States now officially has the cleanest on-road diesel fuel in the world.

“This year has included several important environmental landmarks – the 40th anniversary of the Clean Air Act, the 10th anniversary of the National Clean Diesel Campaign, and now the official completion of the new ultra-low sulfur diesel transition.

“The new clean diesel fuel will be a major contributor in helping cities and states meet strict new air quality goals set by the federal government,” Schaeffer said.

“This new, ultra-clean fuel is extremely important because sulfur tends to hamper exhaust-control devices in diesel engines, like lead once impeded the catalytic converters on gasoline cars. Just as taking the lead out of gasoline in the 1970s enabled a new generation of emissions control technologies that have made gasoline vehicles over 95 percent cleaner, removing the sulfur from diesel help usher in a new generation of clean diesel technology.

“But we’re not stopping here. We’re also continuing our important work to transition off-road vehicles like farm tractors and construction machines to ultra-low sulfur diesel fuel. Construction and agricultural equipment manufacturers are well on their way to launching a new generation of low-emission clean diesel engines that will require this cleaner fuel.

This effort is important toward decreasing emissions throughout the nation. Two-thirds of all farm and construction equipment rely on diesel engines due to their unique combination of power, fuel efficiency, economical ownership and operation and legendary reliability and durability.”