United States             Air and Radiation         EPA420-F-98-018
                   Environmental Protection                         May 1998

                   Office of Mobile Sources
&EPA       Regulatory
                  Advance Notice of Proposed Rulemaking:
                  Emission Standards for New Large
                  Spark-Ignition Nonroad Engines
                   The U.S. Environmental Protection Agency (EPA) is issuing an
                   advance notice of proposal for control of emissions from new spark-
                   ignition engines rated above 19 kilowatts (25 horsepower). Control of
                   emissions from this currently unregulated source moves the Agency
                   one step further in the initiative to reduce the harmful health effects of
                   ozone and particulate matter from nonroad engine sources.
                  A National Emission Control Program

                  The results of an EPA study completed in 1990 demonstrated the need for
                  control of air pollution in the nonroad engine and vehicle arena. EPA
                  published this finding in conjunction with the first rulemaking to set
                  emission standards for nonroad engines, which was completed in June
                  1994. In September 1997, the Agency issued a proposal for more strin-
                  gent emission standards for diesel engines used in most nonroad applica-
                  tions. EPA has subsequently finalized emission standards for spark-
                  ignition nonroad engines rated at or below 19 kilowatts, which consist
                  predominantly of residential and commercial lawn care equipment. The
                  Agency is now considering proposing a national program to control
                  emissions of oxides of nitrogen (NOx) and hydrocarbons from large
                  spark-ignition nonroad engines. These engines are used in a variety of
                  industrial equipment, including forklifts, airport ground-service equip-
                  ment, generators, and compressors. EPA is publishing an Advance Notice
                                                         > Printed on Recycled Paper

of Proposed Rulemaking (ANPRM) to encourage a broader dialogue
with the public regarding the emission standards under consideration.
Many of the engines that would be affected by these new emission
standards have counterpart engine models used in highway applications.
While highway engines have seen extensive technological developments,
the nonroad engine designs have changed little to reflect these improve-
ments. Shifting toward these technologies that have been developed for
cars and trucks, such as electronically controlled closed-loop injection
systems with three-way catalysts, there is a great potential to dramati-
cally improve engine performance and fuel economy in addition to the
anticipated emission reductions.
Emissions from Large Spark-Ignition Nonroad
If the standards are implemented as discussed, the resulting emission
reductions would translate into significant, long-term improvements in
air quality in many areas of the U.S. Application of basic automotive
emission control technologies would reduce NOx and hydrocarbon
emissions by 70 to 90 percent. The emission standards being considered
are part of an overall program designed to ensure that engine emissions
are controlled throughout a lifetime of field operation, not just in the
laboratory. Overall, the program would provide much-needed assistance
to states facing ozone and particulate air quality problems that are
causing a range of adverse health effects for their citizens, especially in
terms of respiratory impairment and related illnesses.
Public Participation Opportunities
EPA desires full public participation in the rulemaking process. The
Agency solicits comments from all interested parties. Wherever appli-
cable, full  supporting data and detailed analysis should also be submitted
to allow EPA to make maximum use of the comments. Commenters are
especially  encouraged to provide specific suggestions for changes to any
aspects of the proposal that they believe need to be modified or im-

EPA will accept comments on the ANPRM for 30 days after publication
in the Federal Register. For instructions on submitting written com-
ments, please see the Federal Register notice, which is available from

the EPA Air and Radiation Docket by calling 202-260-7548; please refer
to Docket No. A-98-1. In addition, the ANPRM and related documents
are available electronically via the EPA Internet server at:


There will also be an opportunity for oral and written comment when
EPA publishes a subsequent Notice of Proposed Rulemaking.
For More Information

Document information is also available electronically at the Internet site
given above, or by writing to:

       U.S. Environmental Protection Agency
       Office of Mobile Sources
       2000 Traverwood
       Ann Arbor, MI 48105