The long-awaited regulation requires a 35 percent reduction in emissions from new lawn and garden equipment beginning in 2011. Big emission reductions are also required for speedboats and other recreational watercraft, beginning in 2010.
The reductions will be the equivalent of removing one out of every five cars and trucks on the road, according to Bill Becker, executive director of the National Association of Clean Air Agencies.
EPA said approximately 190 million gallons of gasoline will be saved each year when the rules take effect, and more than 300 premature deaths prevented annually.
"These standards help fight smog in our neighborhoods and waterways as we continue to improve the environmental landscape," said EPA Administrator Stephen L. Johnson.
The regulation had been delayed for years by opposition from Sen. Kit Bond, R-Mo., who took up the cause of small-engine manufacturer Briggs & Stratton Corp., which builds many of its engines in Missouri. The final rule Thursday was issued more than a year after the draft rule came out in April 2007.
EPA estimated the cost of implementing the reductions at $236 million a year, which will likely make its way to consumers in the form of more expensive lawnmowers and other machines.
Industry groups said exact figures were difficult to calculate, but the California Air Resources Board has estimated that walk-behind mowers would cost 18 percent more under the new regulation, while the price of commercial turf care mowers would rise about 3 percent.
"It's been an undertaking," said Kris Kiser, vice president of public affairs at the Outdoor Power Equipment Institute, Inc. "Challenging, but again, fair and achievable and it's the right thing to do."
Environmentalists welcomed the regulation, which applies to lawn care engines under 25 horsepower and to a full range of gas-powered personal watercraft. The rule requires a 70 percent reduction in emissions from recreational watercraft.
"These new clean air standards will reduce dangerous smog pollution from high-emitting gasoline engines while helping to cut costs at the gas pump," said Vickie Patton, the Environmental Defense Fund's deputy general counsel.
The reductions on lawn mower emissions will probably be accomplished by adding catalytic converters that reduce pollution from exhaust but add cost.
Some in industry resisted the change, and Briggs & Stratton found a vocal champion in Bond. He and fellow Appropriations Committee member Sen. Dianne Feinstein, D-Calif., spent years sparring over the issue after California sought EPA permission to implement its own small engine controls in 2003.
Bond tried to insert language in a spending bill to keep the state from doing so, but backed off under pressure from Feinstein, and California began implementing its rules last year. Bond did succeed in blocking other states from being able to copy California's rule, something the Clean Air Act normally allows. Instead, he required EPA to write the national standard that was issued Thursday.
Bond had questioned whether mowers with catalytic converters could spark fires, but an EPA study done at his behest found there was no safety problem - even while further delaying implementation of the rule.