New ultra-clean diesel begins flowing toward the District

In a move being hailed as one of the most significant clean-air upgrades since lead was removed from gasoline decades ago, a new blend of ultra-low-sulfur diesel fuel is on its way to pumps in the Washington region and across North America.

New federal laws requiring that at least 80 percent of the diesel fuel refined in the U.S. be ultra-low-sulfur kicked in Thursday. The new fuel will contain 97 percent less sulfur than today’s diesel — down from 500 parts per million to 15.