United States Air and Radiation EPA 420-F-96-005 Environmental Protection June 1996 Agency Office of Mobile Sources --------------------------------------------------------------------- EPA Environmental Fact Sheet --------------------------------------------------------------------- Revision of Carbon Monoxide Standard EPA is proposing to increase the Phase 1 carbon monoxide emission standard for Class I and II nonroad engines to 519 g/kW-hr. This standard would apply to new spark-ignition engines at or below 19 kilowatts used in nonhandheld applications. EPA Is Petitioned to Revise Current Standard In July 1995, the Environmental Protection Agency (EPA) finalized the first phase of national regulations to control emissions from spark-ignition (SI) engines at or below 19 kilowatts (or 25 horsepower). This regulation, referred to as ÒPhase 1,Ó applies to engines manufactured during or after 1997. In March 1996, Briggs and Stratton Corporation submitted to EPA a petition requesting reconsideration and revision of the certification fuel requirements and carbon monoxide (CO) emission standard for nonhandheld engines. Briggs and Stratton argues that a correction to the Phase 1 rule is necessary because a significant percentage of the market cannot achieve the existing CO standard with the specified fuel in the necessary timeframe. EPA Proposes Revision of CO Standard In response to the petition and after review of test data, EPA is proposing to increase the Phase 1 CO emission standard for Class I and II nonroad engines from 469 grams per kilowatt-hour (g/kW-hr) to 519 g/kW-hr. This standard would apply to new SI engines at or below 19 kilowatts (25 hp), which are used to power nonhandheld equipment such as lawnmowers. This revision is necessary to address the CO emission difference between oxygenated and nonoxygenated fuels that was not reflected in the Phase 1 final rule. This correction would ensure that the CO standard is achievable and technically feasible for manufacturers to certify their engine models to the Phase 1 emission standards and make them commercially available for the 1997 model year. In addition, EPA is proposing to give the Administrator the option to permit the use of open crankcases in engines used exclusively to power snowthrowers. This proposed change will give EPA the flexibility to allow certain engine manufacturers to certify engines to be used in snowthrowers without making technological changes that would severely impair the ability of the engine to function or that would be economically prohibitive. EPA Seeks Public Participation EPA invites public comment to this proposed rule. For instructions on submitting written comments, please see the Federal Register notice. It is available from the EPA Air and Radiation Docket by calling 202-260-7548; please refer to docket number A-96-02. In addition, the rule is available electronically via the EPA internet server and via dial-up modem on the Technology Transfer Network (TTN), which is an electronic bulletin board system (BBS) operated by EPAÕs Office of Air Quality Planning and Standards: World Wide Web: http://www.epa.gov/OMSWWW TTN BBS: 919-541-5742 (1200-14400 bps, no parity, 8 data bits, 1 stop bit); voice helpline: 919-541-5384 For More Information For more information on this rulemaking, please call the Office of Mobile Sources at 313-741-7803 or write to: US Environmental Protection Agency National Vehicle and Fuel Emissions Laboratory Engine Programs and Compliance Division 2565 Plymouth Road Ann Arbor, MI 48105