WASHINGTON, May 10 — The Bush administration announced new regulations on Monday that will significantly reduce emissions from tractors, bulldozers, locomotives, barges and other nonroad vehicles propelled by diesel fuel that altogether spew more soot than the nation's entire fleet of cars, trucks and buses.
Michael O. Leavitt, administrator of the Environmental Protection Agency, said after a meeting with President Bush that the regulations would be made official on Tuesday, setting in motion a plan for full compliance by 2012.
The new regulations require refineries to produce cleaner-burning diesel fuel and engine makers to cut diesel emissions by more than 90 percent, a reduction that health experts say could prevent as many as 12,000 premature deaths and 15,000 heart attacks every year.
"This is a big deal," Mr. Leavitt told reporters after the meeting at the White House, comparing the importance of the new diesel standards to regulations decades ago that took lead out of gasoline. "The result of this is that people will live longer, live better and live healthier lives."
The new regulations, the first for this group of vehicles, were developed through years of collaboration among environmental groups, public health advocates, engine makers and fuel refineries. Representatives from all of the groups said the adoption of the new standards reflected an extraordinary, and unusual, willingness of the E.P.A. to listen to everybody.
"The process they used was unlike any other process I've ever seen," said Bill Becker, executive director of two groups that represent state and local air pollution agencies. "They opened the door, let everybody in and made us all feel like the favorite child of the parent."
The goal of the new standards is to lower the sulfur content of diesel fuel that is used in engines, some as large as 6,000 horsepower. Sulfur not only leads to more particulate matter, better known as soot, in the atmosphere, but it also prevents newer engine technologies from reducing the levels of other pollutants.
Stronger regulations for buses and trucks that use diesel fuel were adopted in the final days of the Clinton administration. They were kept in place by Mr. Bush and are set to take effect in 2007.
The new regulations build on that effort, with all nonroad diesel vehicles, except for locomotives and marine vessels, required to reduce the sulfur content of diesel fuel to 500 parts per million by 2007 and to 15 parts per million by 2010. Locomotives and boats have an additional two years, to 2012, to reach the lower standard.
Currently, the average level of sulfur content is 3,400 parts per million.
The environmental agency predicts that once the current fleet of diesel-powered engines is retired, the level of nitrogen oxides in the air will be reduced by 738,000 tons annually and the level of soot by 129,000 tons.
Industry leaders, as well as environmentalists, said progress toward the new regulations came about through several factors, including public pressure on the administration to produce tangible evidence of interest in cleaning the air, a willingness of refineries and engine makers to bear the enormous costs of improvement in exchange for a longer phase-in period and a realization by environmental groups that the new standards will have a substantial health benefit even if they take some years to put into practice.
Edward Murphy, an official with the American Petroleum Institute, said: "This means a huge investment for us, in the billions. We're concerned about the cost, but it's worthwhile because the environmental benefits justify it."
Jed Mandel, a spokesman for the Engine Manufacturers Association, a trade organization, said, "The industry members are committing themselves to developing new products, not fighting the idea of getting more emission reductions."
Phil Clapp, president of the National Environmental Trust, which has battled the White House on other environmental issues, said the new regulations placed the biggest financial burden on two companies that make a variety of diesel-powered engines, Cummins and Caterpillar. But because one company, Cummins, is based in Indiana, a state Mr. Bush is sure to win in the November election, and the other in Illinois, which Mr. Bush will probably lose, Mr. Bush is not likely to suffer any adverse consequences, Mr. Clapp said.