WASHINGTON - Gasoline-powered lawnmowers that cause summertime air pollution will have to be dramatically cleaner under rules issued Thursday by the Environmental Protection Agency.

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, said Bill Becker, executive director of the National Association of Clean Air Agencies. EPA said about 190 million gallons of gasoline will be saved each year when the rules take effect.

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, 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. The regulation 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. The reductions on lawn mower emissions will probably be accomplished by adding catalytic converters that reduce pollution from exhaust but add cost.

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