This action establishes the first phase of regulations to control emissions from new nonroad spark-ignition engines at or below 19 kilowatts (25 horsepower). Regulatory requirements will for the first time control emissions from these engines, which cause or contribute to nonattainment of National Ambient Air Quality Standards for carbon monoxide (CO) and ozone. These engines are used principally in lawn and garden equipment. The new standards are expected to result in a 32 percent reduction in hydrocarbon (HC) emissions and a 7 percent reduction in CO emissions from these engines in the year 2020, when complete fleet turnover is projected. A second phase of regulations addressing emissions from these engines is currently under development.