The Bush Administration has approved new EPA rules to cut levels of NOx and particulate matter in construction, agricultural and industrial diesel-powered equipment by over 90% between 2008 and 2015.

The smallest engines from those classes of equipment must adhere to the new rules by 2008; the larger engines must be in compliance by 2015.

Sulfur levels in the diesel fuel used for those engines will be reduced as well, falling from 3,000 parts per million (ppm) today to 500 ppm in 2007 and 15 ppm by 2010.

The EPA noted that these rules are designed to emulate the tougher '07 emissions standards on the books for commercial vehicles.

The agency also took the first step toward creating new emission standards for diesel engines used in locomotives and marine vessels by issuing an advance notice of proposed rulemaking. Standards being considered would apply to new marine diesels and both new and existing diesel locomotives.

“We are going to make that burst of black smoke that erupts from diesels a thing of the past,” said EPA Administrator Mike Leavitt.