EPA sets lower emissions regulations for mowers

The U.S. Environmental Protection Agency recently updated its regulations for emissions from "small spark-ignition engines"—that is, your lawn mower or tractor and other outdoor power equipment.

As with earlier phases of these regulations (see chart, below), the latest guidelines, Phase 3, further reduce levels of hydrocarbons and nitrogen oxides, contributors to ground-level ozone and smog, from the exhaust of gas-powered mowers, tractors, and other handheld outdoor gear, including generators. (It also affects in- and outboard engines and other marine equipment.) For the first time since 1997, when the first phase of emissions regulations took effect, the new regulations also limit hydrocarbons that evaporate from the tank, hoses, and other components when the equipment is off.

The new regulations take effect in 2011 for tractors and other riding models and in 2012 for mowers. Eighty percent of Class I (walk-behind mowers) and nearly 70 percent of Class II (riding mowers) engine families from the leading manufacturers would have to be redesigned to be compliant, according to EPA documents. Engine manufacturers won't necessarily have to bring every engine down to the new levels, but the weighted averages of the company's line in a given year will need to comply.

"From an exhaust standpoint, these standards are the most stringent, and probably the most technically difficult, to deal with so far," says Tom Savage, senior vice president of engineering at Briggs & Stratton, which sells engines and also lawn equipment under Simplicity, Snapper, and other lines.

The California Air Resources Board (CARB) recently revamped its own emissions standards for walk-behind mowers built as of model-year 2007 and ride-on mowers starting in model-year 2008; the EPA's Phase 3 standards for Class I and II engines are similar to CARB's.

The EPA estimates that the price of a typical walk-behind mower could rise by $15 to $28 in the near term, though CARB's own estimates are roughly double. The price of riding models, says the EPA, could rise by $50 to nearly $100. The price hikes could be tied into catalytic converters, which the federal government has required on cars and light trucks since the 1970s. Some mower and tractor manufacturers might use catalytic converters to comply with the new regulations.

Mowers and tractors built under the new EPA regulations should use less gas, possibly offsetting the price increase, says Kris Kiser, senior vice president of public affairs for the Outdoor Power Equipment Institute, a manufacturer trade group. "There will be some gasoline cost savings over the life of the product," he says. You'll need to follow the recommended maintenance for your yard gear to maximize fuel savings.

Some have objected to the EPA ruling, noting that catalytic converters run hot enough to pose a threat of fire when the engine is used in dry, heavy growth or near lawn debris. The EPA, however, says that the new standards should not pose any additional threat of fire or injury and that compliance with the standards could even reduce the risk to consumers.— Ed Perratore

Essential information: Learn more about the different types of mowers, mowing safety, emissions, and robotic mowers and electric mowers. When you're ready to buy, read our latest mowers review, and refer to our ratings of push and self-propelled mowers and tractors (available to subscribers).