New rules governing off-road diesel engines, announced last week by the Environmental Protection Agency and applauded by conservation and health groups, show that good policy can be developed when both industry and environmental interests are heeded. Not only are activist groups praising the rules, which will significantly reduce particulate emissions, they were pleased to be included in the process.

Hopefully, this happy outcome signals that the EPA, under the direction of Michael Leavitt, who has been on the job for six months, is moving toward a more inclusive rule making process. In this regard, the diesel rules are a contrast to proposed mercury emissions rules, language in which was lifted directly from industry memos, or the administration’s abandonment, against the advice of scientists within the EPA, of “new source review” requirements that pollution control equipment be installed at facilities that undergo major upgrades.

The new diesel rules will reduce the emissions of nitrogen oxides and other pollutants from logging equipment, tractors, bulldozers and other diesel-powered equipment by more than 90 percent over the next eight years. This will prevent more than 12,000 premature deaths and save billions of dollars in hospital and medical costs in 20 years, according to agency predictions. Stricter rules for diesel buses and trucks were adopted during the final days of the Clinton administration and are set to take affect in 2007.

The 1 million off-road diesel engines affected by the new rules make up less than 5 percent of the U.S. vehicle fleet but account for nearly half of the fine soot, or particulate matter, and a quarter of smog-causing nitrogen oxides emissions from mobile sources, according to the EPA. In Maine, such off-road vehicles emit at least 126 tons of volatile organic compounds and 54 tons of nitrogen oxides per day, according to a 1999 Department of Environmental Protection inventory.

To meet the new rules, engine manufacturers will have to build engines that remove more particles in emissions and fuel refiners will have to produce cleaner diesel fuel. Refiners must cut the sulfur content of nonroad diesel fuel by 99 percent from its current 3,400 parts per million to 500 parts per million in 2007 and 15 parts per million in 2010. The one concession to industry was to delay the latter requirement for marine and locomotive engines until 2012. Sulfur can destroy emission control systems used in diesel engines.

Industry executives say it will cost billions of dollars to meet the new rules, but, in the words of an official with the American Petroleum Institute, “it’s worthwhile because the environmental benefits justify it.”

Perhaps something is in the air.