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Regulatory

Announcement

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-99-027

June 1999

Office of Mobile Sources

Reproposed Phase 2 Standards for

Small Spark-Ignition Handheld

Engines

History of Rulemaking

In July 1995, EPA finalized the first federal regulations affecting small

nonroad SI engines at or below 19 kilowatts (kW), or 25 horsepower.

The regulations, commonly known as “Phase 1,” took effect for most

new handheld and nonhandheld engines beginning in model year 1997

and are expected to result in a 32 percent reduction in HC emissions

from these engines. Table 1 lists the different small SI engine categories,

including the newly proposed Class I-A and I-B designations.

The U.S Environmental Protection Agency (EPA) is reproposing Phase

2 emission standards and other regulatory requirements for nonroad

small spark ignition (SI) handheld engines (such as trimmers, brush

cutters, and chainsaws). Small SI engines currently produce

approximately one tenth of U.S. mobile source hydrocarbon (HC)

emissions and are the largest single contributor to nonroad HC

inventories. Thus, the proposed Phase 2 standards would help the

States in their progress towards compliance with the National Ambient

Air Quality Standard (NAAQS) for ozone.
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In September 1993, the Agency initiated a regulatory negotiation (or

"reg-neg") to develop a framework for a “Phase 2” rule. The reg-neg

ended in February 1996 without a consensus among all the participants

on a Phase 2 program. However, EPA continued to work with several

former reg-neg members.

In March of 1997, EPA published an Advance Notice of Proposed

Rulemaking (ANPRM) announcing the Agency’s intent to issue a Notice

of Proposed Rulemaking (NPRM) which would cover both handheld and

nonhandheld engines. The ANPRM also published the text of two Statements of Principles (SOPs) which were developed between the Agency

and other interested parties in 1996. In January of 1998, the Agency

published the NPRM for the Phase 2 regulations for small SI engines,

both handheld and nonhandheld engines, based on the SOPs.

Since the publication of the January 1998 NPRM, there have been rapid

and dramatic advances in emission reduction technologies for handheld

engines used in applications such as trimmers, brush cutters, and

chainsaws. EPA had not been able to fully evaluate these technologies or

discuss their possible availability at the time of the January 1998 NPRM.

Having reviewed the available information regarding these new technologies, EPA now believes this new information supports proposed Phase 2

standards for handheld engines that are significantly more stringent than

those proposed in the January 1998 NPRM.

In light of this information, and in the interest of providing an opportunity for public comment on the stringent levels being considered for the

Phase 2 handheld engine emission standards and the technologies available for meeting these standards, EPA is reproposing the Phase 2 regulations for handheld engines in this Supplemental Notice of Proposed

Rulemaking (SNPRM). EPA finalized Phase 2 regulations for

nonhandheld engines in a Final Rulemaking (FRM) in March of 1999.

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Reproposed Standards

The reproposed emission standards are considerably more stringent than

those originally proposed in the January 1998 NPRM for handheld

engines. In addition, the reproposed compliance program provisions are

similar to those recently adopted for nonhandheld engines and reflect

closer harmonization with those required by the State of California.

This proposal will reduce hydrocarbons plus oxides of nitrogen

(HC+NOx) by an additional 78 percent beyond the current Phase 1

standards. The reproposed rule includes provisions that give industry

flexibility and ease the transition to the more stringent Phase 2 program,

especially for small volume engine and equipment manufacturers. The

new standards would be phased in beginning with the 2002 model year.

EPA is also proposing standards for two additional classes of

nonhandheld engines that would apply to engines below 100 cubic

centimeters displacement used in nonhandheld equipment applications.

Overview of the Reproposed Rule for Handheld

Class III, IV and V Engines

This SNPRM proposes emission standards and other regulatory requirements for Class III, IV and V engines as used in handheld equipment

applications. The reproposed Phase 2 program for handheld engines is

expected to result in a shift to dramatically cleaner engine technology. In

addition, the proposed Phase 2 rules include new programmatic requirements to ensure that engines meet the tighter standards throughout the

useful life of the equipment. Highlights of the proposed rule include:

• Tighter emission standards for HC+NOx (in grams per kilowatthour (g/kW-hr)) to be phased-in over a number of years, allowing

the manufacturers an orderly and efficient transition of engine

designs and technologies from those complying with the existing

Phase 1 standards to those necessary to meet the Phase 2 requirements. Table 2 contains the reproposed emission standards for

handheld engines.
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• Three useful life categories for handheld engines to account for

widely varying product lives as noted in Table 3.

• A compliance program to ensure engines continue meeting the

standards for the useful life of the engine, including certification,

production line testing, and voluntary in-use testing.

• An Averaging, Banking, and Trading (ABT) program to provide

engine manufacturers with additional flexibility in meeting the

reproposed Phase 2 handheld standards.

Health and Environmental Benefits

Both HC and NOx contribute to the formation of tropospheric ozone

through a complex series of reactions. In a recent report, researchers

emphasize that both HC and NOx controls are needed in most areas of

the United States. EPA’s primary reason for controlling emissions from

small SI handheld engines is the role of their HC emissions in forming

ozone. Of the major air pollutants for which National Ambient Air

Quality Standards (NAAQS) have been designated under the Clean Air

Act (CAA), the most widespread problem continues to be ozone, which

is the most prevalent photochemical oxidant and an important component of smog.

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The reproposed Phase 2 handheld engine standards should result in a 78

percent reduction in HC+NOx emissions from these engines beyond the

32 percent reduction expected from the Phase 1 standards. This is

equivalent to an annual reduction of 258,000 tons of exhaust HC+NOx

emissions by the year 2027. This reduction in HC+NOx emissions will

be accompanied by an overall reduction in fuel consumption.

Small SI engines currently produce approximately one tenth of U.S.

mobile source HC emissions and are the largest single contributor to

nonroad HC inventories. Thus, the proposed Phase 2 standards would

help the States in their progress towards compliance with the NAAQS

for ozone.

The proposed standards will generate significant reductions in emissions

from these engines with small increases in cost. In addition, the technological changes necessary to bring these engines into compliance with

the proposed emission standards would cause a decrease in fuel consumption of approximately 30 percent for handheld engines, resulting in

even lower costs to the consumer. Table 4 presents the cost effectiveness

of the reproposed Phase 2 program for handheld engines.

Effect on Industry

The proposed rule would require engine manufacturers to:

• build significantly cleaner, more durable engines.

• certify that those engines will meet standards for their full regulatory useful lives.

Some of the technologies currently in development to achieve these

standards with the use of a catalyst (e.g., John Deere’s “LE technology”

and Komatsu Zenoah’s “Stratified Scavenged” design) are anticipated to

be a primary choice for manufacturers of Class III and IV engines to

meet their Phase 2 emission levels. Class V engines are expected to use

the same technologies without catalysts to meet their Phase 2 emission

levels.

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The proposed rule includes provisions to ease the transition from Phase 1

to the Phase 2 program, to ensure that the Phase 2 standards are costeffective and achievable, and to minimize the compliance burden while

maintaining the environmental benefits of the rule. These provisions

include a declining set of average standards, a certification ABT program, and special provisions to ease and/or delay the impact of the

proposed rule on small volume engines and equipment.

Public Participation Opportunities

We welcome public comments on this proposed rule from all interested

parties. For instructions on submitting written comments, please see the

Federal Register notice. It is available from the EPA Air Docket by

calling 202-260-7548; please refer to Docket No. A-96-55. In addition,

the proposed rule and related documents are available electronically via

the EPA Internet server at:

http://www.epa.gov/oms/equip-ld.htm

For More Information

Additional documents on small nonroad SI engines are available electronically at the Internet site given above, or by writing to:

U.S. Environmental Protection Agency

Office of Mobile Sources

2000 Traverwood Road

Ann Arbor, Michigan 48105

(734) 214-4278