### RESPONSE TO COMMENTS ON THE NPRM

Emission Standards for New Nonroad Spark.IgnitionEngines at or Below 19 Kilowatts

# ~**_3o~'1** DRAFT May 27,1995

# EPAAlR~E.l

u.s. Environmental Protection Agency Office ofAir and Radiation Office ofMobile Sources

CertificationDivision-1­


### TABLE OF CONTENTS SECTION 1: INTRODUCTION

........................................................................... 3 SECTION 2: STATUTORY AUTHORITy

...............................................................6 SECTION 3: EFFECTIVE DATE, APPLICABll.JTY, AND DEFINITIONS

.......................7 3. 1 Model Year and Effective Date

.................................................................7 

### 3.2 Nonroad Engine and Vehicle Definitions

.................................................... 11 3.3 Definition ofHandheld Equipment, Snowthrowers, and Two-stroke Lawnmowers

... 

### 12 3.4 Lawnmowers

.................................................................................... 

### 17 3.5 Snowthrowers

...................................................................................22 

### 3.6 Use ofPower Rating as Cutofffor Applicability

...........................................

### 25 3.7 Non-Coverage of Compression-ignition Engines

...........................................

### 26 3.8 Non-Coverage ofRecreational Propulsion Engines

........................................

### 27 3.9 Non-coverage ofMarine Propulsion Engines

...............................................

### 28 SECTION 4: CERTIFICATION REQUIREMENTS AND EMISSION STANDARDS

...........

### 29 4.1 Equipment and Vehicle ManufacturerRequirements

.......................................

### 29 4.2 Engine Family Definition

......................................................................

### 31 4.3 Labeling

..........................................................................................

### 32 4.4 Cap on Noise

..................**~** .................................................................33 

### 4.5 Safety Implications

.............................................................................

### 35 4.6 Retention ofCertification Engine

............................................................

### .36 4.7 CO Standard

.....................................................................................

### 36 4.8. Class V Compliance Margin Language

.......................................................

### 39 4.9 HC. 

### +.NOx Standard

............................................................................

### 40 4.10 Stringency of Standards

....................................................................... 

### .40 4.11 Regulating HC vs. VOC

......................................................................

### .42 SECTION 

### 5: TEST PROCEDURES ANDEQUIPMENT

............................................

### .42 5.1 Certification Test Fuels

........................................................................ 

### .42 5.2 Service Accumulation Fuel (or Break-In Fuel)

.............................................

### .43 5.3 PowerMeasured During the Idle Mode

..................................................... 

### .44 5.4 Differences between the proposed Federal testprocedure and the Society ofAutomotive Engineers (SAE) Recommended Procedure 

### 11088

.........................................45 5.5 Unconditioned Air Supply, Humidity Measurement

...................................... 

### .46 5.6. Test Conditions, Test Engine Orientation

....................................................

### 46 5.7. AmbientTest Conditions and f-parameter Specifications

.................................

### .47 5.8 Oxygen Interference Check

- Frequency ofCheck

........................................ 

### .48 5.9 Carbon Monoxide Analyzer Interference Check

...........................................

### .48 5.10 Calibration Frequency

..........................................................................

### 49 5.11 Test Procedure Overview, Dynamometer Requirement

....................................

### 50 5.12 Recorded Information, Explanation ofTerms

...............................................

### 50 5.13 Humidity and temperature measurement ofengine intake air

..............................

### 50 5. 14. Engine service accumulation time determination

...........................................

### .51 5.15 Effect ofemission measuring equipment on engine performance

.........................

### 52 5.16 The use ofobserved vs. corrected torque in powercalculations

..........................

### 52 5.17 Engine stabilization

- thennal stability requirement

.........................................

### 53 5.18 Data Sampling Period and Frequency

........................................................

### 53 5.19 Averaging of speed and torque data for power calculation

.................................

### 54 5.20 Emission Bench Calibration Information

.............................................."

....

### 55 5.21 Automatic Data Collection Of Continuous Analyzer Response

............................

### 55 5.22 Engine Cooling FanFor AirBlowerslPumps

.............................................. 

### .56 5.23. Analytical Gases

- Pure Gases

................................................................

### 56 5.24. Analytical Gases

- Diluent for Hc-Fid Zero, Span and Calibration Gases

...............

### 57 5.25. Analyzer Calibration

- Step Calibration Requirement

.......................................

### 57 5.26. Oxides ofNitrogen Measurement, Accuracy and Instrumentation

........................

### 58

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-2­



### 5.27. Testing Mode Intervals

.........................................................................59 5.28. Mixing Chamber Requirements

- Helmholtz Frequency Requirement

...................59 5.29. Acceptance ofthe Micro-Dilution Tunnel Testing Method

.................................60 5.30. Air Flow Measurement for Two-Stroke Engines

...........................................60 5.31 Catalyst Durability Cycle: Change to Test Requirements

..................................61 5.32 Exhaust Gas Composition for Testing of Three-Way Catalysts

...........................62 5.33 Deterioration Limits

.............................................................................62 5.34 Purpose ofCatalyst Durability Cycle

.........................................................63 5.35 Worst Case Emitter

.............................................................................65 SECTION 6: SELECTIVE ENFORCEMENT AUDITING

...........................................66 6.1 Attached Equipment During An SEA

.........................................................66 6.2 Additional Parts Necessary For An SEA

.....................................................67 6.3 Annual Limit OfSEAs

.........................................................................68 6.4 Number OfSEAs Per Day

.....................................................................69 6.5 Sampling Plans

..................................................................................70 6.6 SEA Self-Auditing

..............................................................................71 6.7 Audit from Engine Family orConfiguration?

...............................................72 6.8 SEAs and ManufacturerProduction Schedules

................ ,............................73 6.9 Port Selection for Imported Engine SEA Testing

...........................................74 6.10 In-Use Testing For Phase 2 Versus Sea Auditing

..........................................75 6.11 Designating Official Data

.......................................................................75 6.12 EPA May Specify SEA Governor Set Speeds

...............................................76 6. 13 Duration ofthe SEA

............................................................................76 6.14 Dealers Involved in SEAslRecordkeeping

...................................................77 SECTION 7: IN-USE TESTING

.........................................................................77 SECTION 8: DEFECT REPORTING AND VOLUNTARY RECALL

..............................80 8.1 Definition ofEmissions-related Defect

.......................................................80 8.2 The 25 EngineTrigger

.........................................................................82 8.3 Appropriateness ofVoluntary Recalls

........................................................83 8.4 Description ofMethod for Notifying Owners

...............................................84 8.5 The Five YearReporting Period

..............................................................85 8.6 Extension of 15 Day Reporting Deadline

....................................................86 8.7 Usefulness ofWarranty Data

..................................................................86 8.8 Dealer Concerns

.................................................................................88 8.9 Emission Defect Warranty Requirements

...................................................89 8.10 Independent Commercial Importer (ICI) Program

..........................................93 8.11 Tampering

..................................................................................... '

..93 SECTION 9: ECONOMIC EFFECTS

....................................................................93 SECTION 1 0: ADMINISTRATIVE REQUIREMENTS

...............................................98 10.1 Small Entities

....................................................................................98 10.2 Reporting Burden

...............................................................................99 10.5 HealthEffects!Air

### Toxins

.................................................................... 100 10.6 Modeling

....................................................................................... 101 10.7 Estimate of Use of Fixed Jet Carburetors for Class V

.................................... 101 SECTION 11: ADDmONAL ISSUES

................................................................ 102 11.1 Absence ofAveraging, Banking and Trading Programs

....... , ......................... 102 11.2 Administrative Procedure Act

............................................................... 106 11.3 SIP Credits

.................................................................................... 107 11.4 Metric

........................................................................................... 108 11.5 Service Information

........................................................................... 109 11.6 Consumer/Commercial Terminology

....................................................... 109

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-3­



### SECTION 1: INTRODUCTION

On May 16, 1994, the Environmental Protection Agency (EPA) published in the Federal Register a Notice ofProposed Rulemaking (NPRM) for emission standards for new nonroad spark-ignition (SI) engines at orbelow t9 kilowatts (kW) (hereafter, "small SIengines"). The purpose ofthe small SI engines NPRM, as required by Congress in section 213(a)(3) ofthe amended Clean Air Act, is to regulate emissions from a category ofnew nonroad engines and vehicles that, in EPA'sjudgment, cause orcontribute to airpollution in areas that failed to attain the National Ambient Air Quality Standards (NAAQS) for ozone orcarbon monoxide (CO).

The Agency held a public hearing on this proposal onJune 21, 1994, in Ann Arbor, Michigan. Sixindividuals, representing engine, equipment, and emission controls manufacturers

. and associations, presented prepared statements and answered questions. A transcript ofthe public hearing is available in the docket for this rulemaking. Thepublic comment period during which the Agency accepted written comments on the proposal was originally slated to close on July 15, 1994, but was extendeduntil August 5, 1994. The Agency received submissions regarding the NPRM from 33 commenters, including 16 engine orequipmentmanufacturers ormanufacturer associations, one emission controls manufacturer association, one environmental consulting company, one environmental organization, one equipment dealer association, one private citizen,
one state farm bureau, one professional association, and 10 state or local government agencies or associations.



### How to use this document Thepurpose ofthis document is to summarize and respond to the comments submittedby the public. Included in the document are responses to the issues raised at the public hearing and in the written and oral comments received by EPA. Each ofthe remaining sections ofthis document is structured by topic, rather than by individual commenter. Sections begin with a briefdescription ofthe approach taken in the May 16, 1994 NPRM, followed by a summary ofthe relevant comments and finally by EPA's response to those comments. All ofthe written comments submittedto EPA, as well as records ofall oral comments received during the comment period, are contained in EPA's NonroadEngines and Vehicles Small SparkIgnitionEngine Docket (EPA 

### Air and Radiation Docket, Docket Number A-93-25).

Table 1lists those commenters who expressed their views to EPAregarding this rulemaking.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5121195

### Table 1: List of Commenters on the Small SI Engines NPRM
Ardisam, Inc. Association ofLocalAir Pollution Control Officials (ALAPCO) Auger and PowerEquipment Manufacturers Association (APEMA) The Black

### & DeckerCorporation (BDC) Briggs & Stratton Corporation California AirResources Board (CARB) California Bureau ofAutomotive Repair (BAR) City ofChicago, DepartmentofLaw ECHO, Incorporated Engine Manufacturers Association (EMA) General Equipment Company Holliday Environmental Services, Inc. Honda, American Honda Motor, Co. Ralph Hovnanian, private citizen lllinois Farm Bureau Kohler Co. Kubota Corporation Machinery and Electrical Products (MEP) Manufacturers ofEmission Controls Association (MECA) National ArOOrist Association (NAA) Natural Resources Defense Council (NRDC) North American Equipment Dealers Association (NAEDA) Northeast States for Coordinated AirUse Management (NESCAUM) Onan Corporation Outdoor PowerEquipment Institute (OPEl) Portable Power EquipmentManufacturers Association (PPEMA)

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments onthe NPRM 5127/95-5­

State and Territorial Air Pollution Program Administrators (STAPPA) State ofLouisiana, Department ofEnvironmental Quality State ofNew York, Department ofEnvironmental Conservation State ofTennessee, Department ofEnvironment and Conservation State ofWisconsin, Department ofNatural Resources Tecumseh Products Company The Toro Company

In summary, EPAreceived a range ofcomments; generally the industry and their associations found aspects ofthe proposal too burdensome while the states and environmentalists expressed concern that the NPRM was too lenient on several issues. The mostfrequently addressed issue in the comments was the proposed August 1, 1996effective date. States, with theirconcerns about emission credits, suggested effective dates ranging from January 1, 1996 to
no laterthan the proposed August 1, 1996 date. Industry, on the other hand, prefers a delay in the effective date, and thus supported options ranging from January 1, 1997 to January 1, 1999. Many othercomments addressed the handheld definition, the proposed emission standards, and details ofthe test procedure. Industry also expressed concern about certification and in-use testing requirements, and believed EPA to have underestimated the economic costs ofthe proposal. In addition, many industry entities raisedconcerns about post-certification issues such as Selective Enforcement Audits (SEA), defect reporting and voluntary recall, and emission defect warranties. After reviewing the comments and the data submitted by some ofthe commenters, EPA developed a final rule that incorporates many ofthe ideas raised.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95

### SEC1"ION 2: STATUTORY AUTHORITY Summary of the Proposal Inthe proposal, EPA cited those sections ofthe Clean Air Act that provide authority for the requirements contained in the proposal, and discussed the mandate ofCAA section 213. The emission contribution ofthe subjectengines as indicated in the Nonroad Studyl was presented, and the background ofthe rulemaking was detailed. 

### Summary ofthe Comments The Portable PowerEquipment Manufacturers Association (PPEMA) commented that EPA failed to make an affInnative significance determination that small engines contribute significantly to ozone orCO in nonattainment areas; without such a determination, according to PPEMA, EPA's emission standards lack statutory authority.2


### EPA's Response to the Comments EPAdoes not agree. In the proposal's statutory authority discussion, EPA stated its finding that small engines are a class orcategory ofnonroad engines that contribute to airpollution. See 59 FR25399 at 25400 (May 16, 1994). EPA also cited section 213(a)(3)'s requirement that EPA regulate those classes orcategories ofnew nonroad engines that, in EPA'sjudgment, cause
or contribute to ozone orCO in nonattainment areas. EPA did not make a finding under section 213(a)(4) with respect to other pollutants, as it did in the large CIproposal, because EPA did not propose to regulate small engine emissions other than VOCs, CO, orNOx. The statutory authority discussion specifically incorporates by reference the significance determination for nonroad engines proposed on May 17, 1993 (58 FR 28809), which was finalized as proposed at 59FR 31306 (June 17, 1994). In the proposal's background discussion, EPA states that small SI engines are the source offive percent ofsummer VOCs in the 19 ozone
nonattainment areas included in the Nonroad Study, and five percent ofwinter COemissions in the 16CO nonattainment areas included in the study. See 59FR 25399 at 25400 (May 16, 1994). EPA does not agree that a finding ofsignificantcontribution must be made for each class or category ofnonroad engine regulated under section 213(a)(3). Paragraphs (1) and (2) ofsection 213(a) make it clearthat EPA's significance determination should be based on whether emissions from all new .and existing nonroadengines are significant contributors to ozone orCO concentrations. There is no indication thatthe significance determination should be based on contributions from various subcategories ofnonroad engines. By contrast, ifthe Administrator makes an affmnative decision regarding aggregate significance, then section 213(a)(3) requires the Administratorto promulgate regulations for those claSses and categories ofnonroad engines and

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-7­

vehicles "which in the Administrator'sjudgment cause, orcontribute to, such air pollution." This mandate does not include any reference to a determination ofsignificance for classes orcategories. Moreover, EPA's interpretation is supportedby the legislative history ofthe Act. See S. Rep. No. 228, WIst Cong., 1st sess. 103-105 (1989); H. Rep. No. 490, WIst Cong., 2nds sess. 309-310 (1990); CHAFFEE-BAUCUS STATEMENT OF SENATE MANAGER, 136 Congo Rec. at S16938 (daily ed., Oct. 27, 1990). EPA notes that the requirement in the Senate bill that would have mandated EPA to make individual significance determinations for eachclass orcategory regulated was deleted from the Clean Air Act as it was finally passed by Congress. Thus, the Agency believes Congress did not intend a showing ofsignificant contribution to be required for regulation ofclasses or categories ofnonroad engines and vehicles. This issue is discussed in further detail in the large CI final rule at 59 FR 31306, 31309 (June 17, 1994).



### SECTION 3: EFFECTIVE DATE. APPLICABILITY. AND DEFINITIONS



### 3.1 Model Year and Effective Date
3.1.1 Summary o/theProposal This rule will become effective beginning with the 1997 model year. EPA proposed an effective date ofAugust 1, 1996 for implementation ofthis rulemaking; engines manufactured on
or after August 

### 1. 1996 for use within the U.S. would have been subject to the standards and requirements ofthe rule. On model year, EPA proposed in the alternative: (1) a model year beginning August 1 and ending July 31 ofthe succeeding year, (2) a model year like that in the onhighway program, and (3) a model yearlike that in the on-highway program but running from August to July rather than January to December.


### 3.1.2 Summary o/the**Comm~nts** EPA received comment on the proposed effective date from manufacturers and industry associations, states and state and local air officials, and an environmental association. Several states, state and local air officials, and an environmental association supported an effective date of January 1, 1996.3 They argued that delayed implementation decreases the value ofa phased approach to small engine regulation by eroding the near-tenn benefits ofa programintended largely to provide near-tenn benefits.4 A state, an environmental association, and associations ofstate and local air officials that are participants in the negotiated rulemaking for the secondphase ofsmall engine regulation stated that their agreement toparticipatein the negotiated rulemaking was based partly on a January 1, 1996 effective date for the Phase 1rulemaking.5

Emission Standards for New-Nonroad Spark.-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-8­

Several states and a manufacturer supported the proposed effective date ofAugust 1, 1996.6 One state argued that industry has had ample notice, and that to delay would reward parties that have not devoted resources in good faith to develop cleanerengines'? Another state commented that it would have to adopt California's regulation for SI engines under 25 horsepower to get the SIPcredits it needs ifthe federal effective date is delayed.8 Several manufacturers and industry associations supported an August I, 1997 effective date, citing lead time considerations.9 An association pointed out that, from the promulgation of the final rule in May 1995 to the effective date ofAugust I, 1996 would provide only one year of lead time priorto implementation. 10 The association stated that one year oflead time is insufficient for engine manufacturers to retool to achieve emission compliance for implementation of

. nationwide standards, orfor equipment manufacturers andcomponent suppliers to modify their

products to accommodate new orredesigned engines.I I Another industry association and a manufacturerpointed outthat an August effective date does not coincide withthe production cycle for all engines covered by this rule; many operate on a calendaryear basis. 12 That association supported an effective date for products that are not preempted in Californiatwo years after California's regulations become effective (e.g., January I, 1997), and an effective date for products that are preempted in Californiatwo years after this Phase I rule takes effect (e.g., January 1, 1999).1 3 The association cited lead time concerns, particularly in regard to products that are preempted from regulation in California. 14 One manufacturer supported a January 1998 effective date for engines used in products that are preempted from regulation in California, arguing that the additional lead time is critical to prevent disruptions 

### in supply since most attention has been focused on engine development for nonpreempted products.15 Otherdates supported by manufacturers orindustry associations include November 1, 1996,16 November I, 1997,17 and January 1, 1998.1 8 Onmodel year, comments were received from manufacturers and industry, state and local air officials', and environmental associations. All comments supported the on-highway model year definition. 19 An industry association stated that the on-highway model yeardefinition would provide needed flexibility in certifying seasonal products.20 Another industry association commented that because the on-highway model year definition allows two frrsts ofAugust, manufacturers would have the greatest flexibility during the period ofthe yearthey are most likely to introduce new models.21


### 3.1.3 EPA IS 

### Response to the Comments EPA is finalizing a model year 1997 effective date and adopting the on-highway model year definition. The 1997 model year will run from January 2, 1996 to December 31, 1997.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-9­

EPA acknowledges industry's need for sufficient lead time. EPA also acknowledges the need ofstates to realize reductions ofair pollutant emissions, and to adhere to schedules mandated in the CAA for reasonable further progress toward VOC reductions from 1990 levels and for attainment ofthe ozone National Ambient Air Quality Standard. The model year 1997 effective date provides additional lead time for those manufacturers that take advantage ofthe flexibility allowedby the model year definition; it also allows early introduction ofcomplying products by manufacturers that are in a position to produce complying products earlierin the model yearrather than later. EPAis allowing

. additional lead time for Class V engines covered by this rule that are used in farm and construction equipment orvehicles which CAA section 209(e)(l)(A) preempts from state regulation. Theeffective date for such Class V engines is January 1, 1998. Although one association commented that even more additional lead time is necessary for preempted products,22 EPA is not persuaded that more additional lead time is essential since manufacturers have already gained increased knowledge ofand experience with the technologies and calibrations that are available for theirengines to meet the standards. Under the final rule, the model yearincludes January 1ofthe calendar year for which it is designated and does not include a January 1ofany othercalendaryear. Themaximum duration of
a model year is one calendaryear plus 364days. A certificate ofconformity is issued for each engine family introduced into commerce for a single model year. The annual production period within a model year for any specific model within an engine family begins either: (1) when such engine is first produced, or (2) onJanuary 2 ofthe calendaryear preceding the year for which the model year is designated, whichever date is later. The annual production period ends either: (1) when the last suchengine is produced, or (2) on December 31 ofthe calendar yearfor which the model year is named, whichever date is sooner. It is a prohibited act to introduce a specific model yearengine into commerce priorto or after the model year for which the certificate is issued and in effect. However, inrecognition ofthe fact that some manufacturers will be in a position to ship certifiedengines prior to January 2, 1996, EPAis making an exception for engine families that are certified by EPA priortoJanuary 2, 1996; such engine families may entercommerce priorto January 2, 1996 once a certificate ofconformity has been issued. Engines produced afterDecember 31 ofthe calendaryear for which the model year is named are not covered by the certificate ofconformity for that model year. A new certificate of conformity demonstrating compliance with applicable standards must be obtained for suchengines,
evenifthey are identical to enginesbuilt before December 31. To provide maximum flexibility in the start-up ofthis program. the Agency is interpreting the Phase 1model yeardefinition somewhat differently than in the on-highway program. Forthe

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-10­

1997 model year only, manufacturers may choose to produce both certified and uncertified engine families during annual production periods that begin prior to September 1, 1996. All engines manufactured during annual production periods that begin on or after September 1, 1996 must be certified. In addition, annual production periods thatbegin priorto September 1, 1996 may not exceed 12 months in length, to ensure that all engines are certified no later than calendar year 1997. EPA has determined that flexibility in the interpretation ofthe model year definition for program start-up is necessary in fairness to manufacturers both to provide necessary lead time and to account for the variability in production periods ofthe small SI engine industry. Forexample, a manufacturer oflawnmowerengines with an annual production period from July 1996 to June 1997 might choose to certify two-thirds ofits engine families by July 1996, with the remainder ofits production being uncertified. Normally, the manufacturer mustcertify all its engines in every annual production period; the enhanced flexibility provided by this special interpretation, which allows manufacturers to choose when to begin certifying in production periods beginning before September 1, 1996, is for the start-up ofthis program only. The lawnmower manufacturer in the above example may call the engine families certified in calendaryear 1996**~ither** modelyear 1996 ormodel year 1997 engines; the advantage to calling them model year 1997 engines is that they can then be built past December 31, 1996. Similarly, the lawnmowerengine families certified in calendar year 1997 may be called model year 1997 or model year 1998 engines, but only model year 1998 engines may be built beyond December 31, 1997. Another example is a string trimmerengine manufacturer that operates on a January to Decemberproduction period. The manufacturer may choose to certify any portion ofits engine families in January 1996, and must certify all its engine families in January 1997. EPA expects that manufacturers will federally certify a substantial number ofengine families in calendaryear 1996 to take maximum advantage of "green" marketing strategies. Most ofthe engine families covered by this regulation will already have been certified to California standards priorto model year 1997. No data are available for EPA to accurately predict the percentage ofsmall engine families that will be certified in calendaryear 1996. Forpurposes of state implementation plan submittals, EPA is estimating that halfwill be certified in calendar year 1996. The model yeardefinition, with a maximum duration ofone calendaryearplus 364days, is primarily intended to allow flexibility in the introduction ofnew models. Underno circumstances should the model yeardefinition be interpreted to allow existing models to "skip" annual certification by pulling ahead the production ofevery other model year. While this situation, to the Agency's knowledge, has not occurred in the past, a practice ofproducing engines for a two year period would violate the Congressional intent ofannual certification based upon an annual

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-11­
production period. The Agency is not currently setting forth rules for how to determine when abuse has occurred, since this has not been a problem to date. However, the Agency is requiring that engine manufacturers certify annually based on an annual production period.



### 3.2 Nonroad Engine and Vehicle Definitions
3.2.1 Summary of the Proposal EPA proposedto incorporate the nonroad engine definition proposed and finalized in the large CI rule. EPA also proposed to amend the definition ofnonroad vehicle proposed in the large CI rule by including nonroadequipment within the definition ofnonroad vehicle. EPA is finalizing these definitions as proposed.


### 3.2.2 Summary ofthe Comments EMA, OPEl, and PPEMA object to the definitions. EMA and OPEl object to the nonroad engine definition, and to the definition ofthe term "new," and incorporate by reference their comments on the laJ"ge CI rule (EPA AirDocket A-91-24) and the waiver ofpreemption to California for nonroad engine and vehicle standards (EPA Air Docket A-91-18).23 PPEMA objectsto boththe nonroad engine and nonroad vehicle definitions because the definitions are expressed in terms ofengine applications; according to PPEMA, EPA is not authorized to regulate engine applications otherthan vehicles.24 PPEMAcomments that including equipment within the category ofvehicles is a strained interpretation, beyondjudicialtolerance.25 PPEMA accuses EPA ofequating engines with engine applications in an unsuccessful attempt to remain within the authority granted by the CAA.26 PPEMArejects EPA's responses to its comments on the large CIrule.27 PPEMA also requests an explanation ofwhy the nonroad vehicle definition in the proposal is unlike that in the large CIrule, where nonroad vehicle and nonroad equipment are defined separately.28 STAPPA and ALAPCO support EPA's view that Congress used the terms "engine" and "vehicle" in a generally inclusive manner and support adding equipment to the nonroad vehicle definition.29


### 3.2.3 EPA's Response to the Comments Inregard to the objections ofEMA and OPEl to the nonroad engine definition, and to the definition of "new," EPA incorporates by reference its previous response to those comments. See 59 FR 31306,31310-31313 and 31328-31331 (June 17,1994). EPA also stands by its previous response to PPEMA's comments on the nonroad engine definition in the large CIrule (see, e.g., 59 Fed. Reg. 31306,31313-31314). In summary, EPA

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/9512­

is authorized by CAA sections 213 and 301 to regulate both nonroad equipment and particular applications ofnonroad engines, as well as nonroad engines and nonroad vehicles. The final large CIrule includes a definition for nonroad equipment. In Phase 1, the definition ofnonroad equipment is incorporated into the definition of nonroad vehicle. EPA does not agree that including equipment with vehicles in a definition for the purposes ofnonroad engine regulation is an interpretation beyondjudicial tolerance. Rather, EPA is refining a term ofart for the purposes ofthese regulations; it is simply more efficient as well as convenienttorefer to nonroad engines and vehicles than to nonroad engines, vehicles, and equipment. Moreover, EPA notes that Congress clearly intended for nonroad equipmentto be included within the regulatory scope ofthis rule, as is shown by the legislative history. See S. Rep. No. 228, 10ist Cong., 1st sess. 104 (1989).



### 3.3 Definition of Handheld Equipment, Snowthrowers, and Two-stroke Lawnmowers
3.3.1 Summary of the Proposal The Agency proposed that small SIengines be categorized as either handheld or nonhandheld, depending onthe usage ofthe equipment in which the engine is installed. To qualify
as handheld, it was proposed that the engine be required to meet at least one ofthe following three criteria: (1) the engine mustbe used in a piece ofequipment that is carried by the operator throughout the performance ofthe intended function(s); (2) the engine must be used in a piece ofequipmentthat must operate multipositionally, such as upside-down or sideways, to meet its intended function(s); or (3) the engine mustbe used in a piece ofequipment for which the combined engine and equipment dry weight is under 14 kg, no more than two wheels are present, and at least one ofthe following attributes is also present: (a) the operatormust alternately provide support orcarry the equipmentthroughout the performance ofits intended function(s); (b) the operator must provide support or attitudinal control for the equipment throughout the performance ofits intended function(s); or (c) the engine is used exclusively in a hand portable generator orpump.


### 3.3.2 Summary ofthe Comments Comments onthis issue were submitted by several engine and equipment manufacturers and theirrespective associations, as well as by environmental and state organizations. 

### In general, state and environmental organizations suggested that EPAtighten the definition to further limit the extent ofthe handheld category and prevent abuse ofthe classifications, while manufacturers and

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-13­

their organizations suggested loosening the definition to allow the equipment ofconcern to their group to fall into the handheld category. Specific suggestions for tightening the handheld definition included adopting CARB's defmition with perhaps a list ofadditional equipment that the EPA wished to define as handheld,30,31,32 revising the weight limit for handheld equipment downward,33,34 revising the definition to include only equipmentfor which the operator bears the entire weight during all nonidle operation,35 tightening the use ofthe tenns "support" and "attitudinal control,"36,37 removing all products with any wheels from the handheld category,38 and removing lightweight snowthrowers,39,40 pumps and generators41,42,43 from the definition ofhandheld. Specific suggestions for loosening the definition included revising the weight limit upward,44 removing the weight limit completely,45,46 ,47 allowing augers,48 two-stroke lawnmowers,49 and two-stroke snowthrowers50,51,52,53 into the handheld category, and clarifying whether certain pieces of marginal equipment met the definition ofhandheld (specifically, cart-attached cut-offsaws, twostroke three-wheeled edgers up to 

### 30cc,54 hover trimmers,55 and all pumps and generators under 14 kg regardless ofthe usage ofthe same engines in other products56).


### 3.3.3 EPA's Response to the Comments The Agency is retaining its handheld equipmentdefinition largely as proposed, with the only changes being the addition ofa fourth category for one-person augers under 20 kg and the elimination ofthe tenn "exclusively" from the category for pumps and generators. Based on an extensive review ofproductliterature, the Agency believes that this revised definition adequately describes those types ofequipmentthat are legitimately handheld while excluding nonhandheld applications. As described more fully in the preamble to the proposed rule, the necessity for a distinction between handheld and nonhandheld equipment is based in part on the substantial difference between emissions from current four-stroke and two-stroke engines, which is an inherent result of theirdesign differences. Although two-stroke engines have significantly higheremissions, their
use is necessary in some applications because they are generally lighter for the same rated power and can be used in any orientation, unlike their four-stroke counterparts. As a result. applications requiring that the usercarry the device oruse it in multiple positions generally need two-stroke engines atthe current time. Conversely, nonhandheld applications do notrequire two-stroke technology, as they are ground-supported and not multipositional, and hence can and should use the inherently cleaner four-stroke engines. Itis not feasible at this time, given the timing ofthis rulemaking and the currently available technology, to require 

### all engines to meet the four-stroke standards. However, the emission reductions being required by this rule are, on a percentage basis, ofthe same magnitude for the

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. 5/27/95-14­

two-stroke and four-stroke engines. Ofcourse, the Agency is not requiring the use ofeither twostroke or four-stroke engines in any particulartype ofequipment. Iftechnological advances are such that two-stroke engines can meet the nonhandheld standards, manufacturers are free to utilize that technology or any other technology that can meet the standards. The distinction between handheld and nonhandheld is not to specifically limit the use ofany type ofengine but, rather, to limit emissions as much as is achievable while recognizing the unique needs ofhandheld applications. The Agency is sympathetic to comments that it should coordinate its handhelddefinition with CARB. Nevertheless, itbelieves that its definition clarifies and expands on the CARB definition in importantways. 

### An investigation into the types ofequipment each definition would
cover reveals that there is a very high degree ofoverlap. Only a few categories were identified that wouldbe coveredby one but not both definitions. Given the different mandates ofthe two organizations and the specific air quality problems ofthe State ofCalifornia, EPA believes it is not inappropriate for the definitions to be slightly different. Many types ofequipment are counted by both EPA and CARB as handheld, by virtue of the general segments ofthe definitions (criteria (1) and (2) above): being carried by the operator throughout their use and/or being used in multiple orientations. While CARB requires equipment to meet both ofthese criteriato be considered handheld, EPA considers only one tobe sufficient. Nevertheless, the majority ofequipment that consumers wouldconsider handheld are considered to be soby both organizations. This includes string trimmers, hedge clippers, brush cutters, clearing saws, leafblowers, chain saws, and zero- and one-wheelededgers. Additionally, both CARB and EPA are exempting two-stroke engines used in snowthrowers from the nonhandheld standards. CARB is instead requiring two-stroke engines used in snowthrowers to meet the handheld standards; EPA is requiring them to meet the handheld COstandard but will not require themto meet the HC standards, eitherhandheld ornonhandheld, unless manufacturers ofthese engines opt to certify to those HC standards. Thetwo organizations are aware ofonly a few pieces ofequipmentwhich do not overlap. These differences arise from the non-general segments ofthe definitions (criterion (3) above). Specifically, CARB does not considerto be handheldthe following items that EPA would allow to be included in the handheld category: zero- to two-wheeled tillers under 14 kg, two-wheeled edgers under 14 kg, and zero- to two-wheeled pumps and generators under 14 kg. Additionally, EPA is revising its handheld definition to include one-person ice and earth augers under 20kg.57 Certain otherengines

-- specifically, those under 175 hp used in farm and construction equipment

-- are covered solely by EPA regulations. ThIs is because section 209 ofthe CAA preempts engines under 175 hp used in farm and construction equipment from separate coverage by any State orpolitical subdivision. The following is a partial list offarm and construction

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equipment: earth augers, brush cutters and clearing saws 40cc and above, chain saws 45 cc and above, chippers, compressors, continuous diggers, cultivators, agricultural mowing equipment, pumps40cc and above, concrete, masonry, and cutoffsaws, and trenchers.58 Spark-ignited engines at orbelow 19 kW used in these pieces ofequipment are therefore subject only toEPA regulation. Ofthese pieces ofequipment, brush cutters, clearing saws, chain saws, and concrete, masonry, andconcrete/cutoffsaws59 meet EPA's general definition ofhandheld equipment, while pumps, cultivators, continuous diggers, and trenchers must be under 14 kg and have no more than two wheels to be considered handheld, and augers must be under 20kg and be intended for oneperson use to be considered handheld. Chippers, compressors, and agricultural mowing equipment would fall underthe nonhandheld category. Some commenters suggested that equipment weighing 14 kg is too heavy tobe handheld, but didnot suggest an acceptable alternative weight. Although the Agency agrees that 14 kg is indeed heavy for some uses and some consumers, it believes that certain pieces ofequipment at that weight would be used in a handheld manner (such as lightweight edgers and tillers). It is likely that market forces would limit the manufacture and sale of "handheld" equipmentthat is too heavy for the typicaJ consumerofsuch products. Indeed, a review ofproduct literature indicates that 14 kg appears to be the breakpoint that the market has chosen between equipment types powered with two-stroke engines and those poweredby four-stroke. 60,61 Additionally, for products not falling into the general handheld definitioru), a product weight ofless than 14 kg is not, in andofitself, sufficient to qualify as handheld. Such products
are also limitedto no more than two wheels and must require some degree ofoperatorcarrying, support or attitudinal control in orderto qualify as handheld; thatis, they must not be completely ground-supported. The Agency believes that these additional constraints will preventtrue nonhandheld equipmentfrom inadvertently falling into the handheld category. Onthe other hand, the mere fact ofsome degree ofground support should not disqualify a piece ofequipment from the handheld category. Some lightweightproducts requiring some level ofground support, including products with one ortwo wheels, would typically be considered handheld by the general pUblic. Equipment such as tillers andedgers with up to two wheels would require some carrying. support or attitudinal control; lawnmowers and three- and four-wheeled edgers. conversely, would be completely ground-supported and thus not handheld.62 The term "carry" means that the entire weight ofthe equipment is borne by the operator. The term "attitudinal control" is meant to apply to situations where the equipment is partially groundsupported but the operator must regulate its horizontal orvertical position in orderto prevent it from falling over. Similarly, the term "support" is meantto apply to some operatorcontrol to preventthe equipment from falling. slipping or sinking; the entire weight ofthe equipmentdoes not have to be supportedorcarried by the operator. However, ifsuch equipment is over 14 kg. the

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Agency continues to believe, based on its review ofproduct literature, that it is not intended for use in a handheld manner. The Agency does not concurwith one commenter that a tiller meeting the above attributes ofhaving no more than two wheels and requiring some operator support shouldbe considered handheld even though it weighs 

### 33 kg.63 Such a weight is clearly beyond the bounds ofwhat the marketplace has considered handheld and, for such a product, the weight increment between a two-stroke and a four-stroke engine is relatively insignificant. Somecommenters stated that pumps and generators under 14 kg should not qualify as handheld, as the incremental weight ofa four-stroke engine should not be an issue in transport from, say, a truckto a construction site. Although the EPA agrees with this assessment for the example cited, the categorization was intended primarily for small pumps and generators that would be transported into remote areas for emergency work orfor operation ofhousehold equipment in a remote cabin. Transportation in such instances would be much further than to a construction site, and the weight would therefore become more ofan issue. The State ofCalifornia has a special provision allowing such equipment with non-certified engines tobe purchasedby emergency response organizations. The Agency is taking a somewhat different route toward a similarend, while**~aking** these pieces ofequipment more widely available. The Agency wishes to clarify that all pumps and generators under 14 kg with no more than two wheels will be categorized as handheld equipment. The phrase "the engine is used exclusively in a generator orpump" in the definition was not meant to preclude handheld status for pumps and generators withengine models that are also used in otherpieces ofhandheld equipment. Rather, the provision was meanttoprevent equipment manufacturers from installing an engine certified for
use in a handheld pump orgenerator in a piece ofnonhandheld equipment. Equipment manufacturers and importers are prohibited from utilizing engine families certified to the handheld standards in equipment not meeting the handheld definition, and are liable for civil penalties ifthey do so. Thus, the term "exclusively" in the handheld definition is superfluous and has been removed. The Agency also wishes to clarify that only earth and ice augers that are under 20kg (including a bit oftypical size for that model) and are sold for use primarily by one person will be considered handheld. Two person augers, and any auger of20kg or more (including the bit) must meet the nonhandheld standards. The Agency believes that this slightbroadening ofthe definition reasonably responds to the needs ofauger manufacturers to continue toprovide a lightweight, high-strength, high-poweredproduct during the time frame ofthe Phase 1regulations. The Agency does not believe that there is a need for two-person augers to be included as handheld, as weight is much less ofa concern in that case. Additionally, several four-stroke two-person augers
are already on the market, demonstrating the**availabi~ity** offour-stroke technology, its utility to the

. consumer, and its marketability. Finally, concerns that the two-stroke engine models used by

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-17­

auger manufacturers will be discontinued appear tobe unfounded, since these engines are also used in snowthrowers. Thus, their market demand would be sufficient for the engine manufacturers to invest in their redesign so they may meetthe handheld standards and continue to be offered for sale. The Agency was only partially convincedby auger manufacturer comments ofthe technological necessity for two-stroke engines in their products. Tothe extentthat the Agency sees
a need for two-stroke technology on augers atthe current time, it is for one-person augers only. Such equipment may legitimately have a need to retain as light a weight as possible in orderfor one persontobe able to counterthe torque generated by the drilling operation, retain the augerin a vertical position, lift itfrom the hole, and transport it to and from the drilling location. Additionally, in contrast to truly nonhandheld equipment, which is fully ground-supported, augers have no frame, wheels, or other supporting devices and, thus, require operatorcontact for attitudinal control during use. In contrast to otherequipment that is clearly handheld, however, augers tend to be ofa heavier construction in orderto withstand the significant forces they encounter during use, so that the 14 kg weight limitation may not be as relevant to augers as to othertypes of**equip~ent.** A review ofproduct literature and manufacturercomments indicate that
an upper limit of20kgwould include most or all one-person augers currently on the market. Augermanufacturers arepredominantly small companies, and therefore are somewhat constrained in their ability to quickly reengineer their product, acquire a new engine source, and absorb the costs ofa four-stroke engine. It is for this reason, coupled with the technological
reasons cited above, that the Agency is allowing one-person augers under 20 kg to meet the handhelddefinition for this Phase 1regulation ofsmall SIengines. However, this definition will not necessarily be carried into future regulation ofsmall SIengines, such as in the Phase 2 negotiated rulemaking activities currently underway. Comments from augermanufacturers on this rulemaking dwelled largely onthe need to retain the currentproduct, presumably due tocost implications. The Agency believes that reliefis necessary in orderfor these manufacturers to continue to function in the short term and that the special attributes ofaugers set them apart from otherequipment that is clearly eitherhandheld or nonhandheld. However, further clarification ofthe technological need for two-stroke engines in augers would be necessary for the Agency to continue to include theminthe same category as equipment more obviously in need oflight weight and/or multipositional use.



### 3.4 Lawnmowers
3.4.1 Summary of the Proposal

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UnderEPA's proposal, alilawnmowers would be classified as nonhandheld equipment. EPA requested comment on the ability oftwo-stroke lawnmowerengine manufacturers to meet nonhandheld standards, the impact such a requirement would have on such manufacturers, the need for relieffor such manufacturers, and the impact such reliefmight have on the environmental benefits ofthe proposal. EPA requested comment on four options for providing relieffor twostroke lawnmower engine manufacturers.


### 3.4.2 Summary ofthe Comments Two industry associations and one manufacturer recommended that EPA allow two-stroke lawnrnower engine manufacturers to meet handheld standards.64 They commented that two-stroke lawnmowerengines would effectively be eliminated from the market under the proposal.65 One manufacturing company will be particularly impactedby the requirement that lawnrnower engines meet nonhandheld standards because it is the largestproduceroftwo-stroke lawnrnowerengines.66 Itcommented that the definition ofhandheld and nonhandheld should not be used to discriminate against engines according totheir application;67 to bypass the requirement oftechnological feasibility;68 to distort the competitive balance ofthe industry by banning major products;69 and to place disproportionate burdens on one company as the price ofmaintaining an importantproduct line

-- all with no commensurate airquality benefit.70 The company commissioned a report (Heiden Associates, Inc., April 20,**19~3)** that estimatedemissions from two-stroke lawnmowers in the nonattainrnent areas included in the Nonroad Study.71 According to the company, the study found that two-stroke lawnmower emissions account for 3.9 percent ofnonroad VOC emissions in those nonattainment areas.72 The contribution to COwas one halforone third ofthe VOC contribution, and the NOx contribution
was calculated at zero.73 Eliminating two-stroke mowers would not accomplish even a .2 percent nationwide VOC reduction, since four-stroke units would replace the two-stroke units, according to that comment.74 The company originally favored the option for reliefofmeeting handheld standards until Phase 2. Itcommented that this option wouldreduce the disparate impact it would face compared to the rest ofthe industry, and wouldprovide it with the incentive to continue emissions development work.75 Later, supplemental comments favored the declining production cap option.76 

### An industry association commented that lawnmowers withtwo-stroke engines are important to equipment users who have tocontend with steep inclines.77 Ifit is not technologically feasible for two-stroke lawnrnower engines to meet nonhandheld standards, an undue burden could be placed on landscapers and otherusers, according to this comment.78

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A state commented that it sees no reason to grant special concessions to some manufacturers because their current product line uses a more polluting technology than their competitors; such a policy wouldpenalize those manufacturers that hav.e pursuedcleaner technologies.79 The state argued that complying engines are available and a sufficient number of manufacturers participate in the market to ensure competition.80 None ofthe options for relief presented seems wise because none prevents continued use ofhigherpolluting machines when complying engines are available, according to the state.81 Environmental and state and local air officials' associations expressed strong opposition to the options for relieffortwo-stroke lawnmowers; given that 90percent oflawnmowers sold in the U.S. already rely on four-stroke technology, it can't be argued that four-stroke engines are not available technology for alllawnmowers.82 The state and local air officials commented that the expected difference between a two-stroke and four-stroke lawnmower is equivalentto approximately 300 grams ofHC perhour ofoperation, or7,500 grams per yearfor a typical homeowner.83 A new automobile emits roughly 0.7 grams ofHC per mile driven, which means that the difference between a two-stroke andfour-stroke during one hour ofgrass cutting is approximately equi!,alent to the emissions associated with an entire month ofcommuting for a typical driver.84 Formany households, the difference for a single season's mowing could be comparable to nearly an entire year ofdriving, according to the comment.85 Environmental and state and local air officials' associations commentedthat manufacturers have had ample opportunity toreact to requirements thatmightreasonably have been expected.86 These manufacturers participated in the process that led to the December 1990 adoption ofCARB's standards and have already enjoyed a four year period in which to take appropriate action.87 The state and local 

### air officials commentedthatregulatory relieffor these manufacturers would fail to provide appropriate market stimulus in a global marketplace that is increasingly sensitive to environmental performance and fuel economy.88 Those associations also commented that such regulatory reliefwould compromise the effectiveness ofPhase 1, and thereby undermine their acceptance ofthe phased approach to regulation ofsmall engines.89


### 3.4.3 EPA's Response to the Comments EPA is finalizing its proposal that lawnmowers be classified as nonhandheld equipment. However, in response to industry comments, EPAis providing an exception to the nonhandheld standard to allow two-stroke lawnmowerengine manufacturers to produce a declining percentage oftwo-stroke lawnmowerengines that meet handheld standards until model year 2003. This relief for two-stroke lawnmowerengine manufacturers isjustifiedby the economic hardship that would result iftwo-stroke lawnmowerengines were required to meet nonhandheld standards upon the effective date ofPhase 1, andby the need for additional lead time for two-stroke engines used in

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lawnmowers to meet nonhandheld standards; EPA has concluded that handheld standards are the most stringent standards achievable for two-stroke lawnmower engines in the neartenn given these economic hardship and lead time considerations. Economic hardship that would result iftwo-stroke lawnmowerengines were required to meet nonhandheld standards is documented in two sets ofcomments from one engine manufacturer.90 It stated that it wouldbe forced to close a manufacturing plant that employs 230 people unless some fonn ofrelieffrom the requirement that two-stroke lawnmower engines comply with nonhandheld standards is granted.91 The plant is devoted to two-stroke engine operations, according to the comments.92 The manufacturer commented that the declining production option would avoid closure ofthe plant and maintain a minimally necessary market presence for its two-stroke lawnmowers during Phase 1.93 The manufacturer stated that its principal goal and long-tenn strategy is to develop technology that will enable two-stroke lawnmowerengines to meet Phase 2 nonhandheld standards.94 Reducing sales below 50 percent would destroy the market for the product before Phase 2 technology could be implemented, and reduce plant utilization to unacceptable levels, according to the manufacturer.95 The need for additional lead time was a common theme among industry commenters, although only one two-stroke lawnmower engine manufacturer addressed the difficulty, ifnot impossibility, oftwo-stroke lawnmowerengines meeting nonhandheld standards by the effective date ofPhase 1.96 According to the manufacturer, it is not technologically feasible for two-stroke engines to meet nonhandheld standards at this time.97 The manufacturer stated in its comments that more engineering effort is required for two-stroke lawnmower engines to meet handheld standards than for four-stroke engines to meet nonhandheld standards, partly due to the difference in duty cycles for handheld and nonhandheld engines, with handheld engines having the advantage ofa higher horsepower divisor than is obtained under the variable nonhandheld load specifications.98 The manufacturer stated that it is an engineering uncertainty whether and how valve-control techniques developed in the past, to enhance power output for smallertwo-stroke engines used in products such as chain saws, might be used to reduce emissions in lawnmowers.99 Finally, the manufacturer stated that while it is conceivable that its technology development could permit the introduction ofengines meeting the Phase I nonhandheld standards during Phase 1, the prospect ofthis occurring before the year 2001 is remote. 100 CAA section 213(a)(3) specifies that nonroad emission standards must achieve the greatest degree ofemission reduction achievable through the application ofavailable technology, giving appropriate consideration to cost, lead time, noise, energy, and safety. Taking into account the economic hardship and leadtime considerations discussed above, EPA has determined that handheld standards subject to a declining production cap are the most stringentemission standards achievable for two-stroke lawnmower engines atthis time.

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Underthe declining production cap, two-stroke lawnmowerengine manufacturers that wish to continue producing two-stroke lawnmowerengines mustestablish a production baseline. The productionbaseline is the highest number oftwo-stroke lawnmowerengines produced in a single annual production period from 1992 through 1994. Documentation verifying the production baseline must be submittedto EPA with the application for certification. 

### In model year 1997, twostroke lawnmowerengine manufacturers may produce 100 percent oftheir production baseline, which must be certified to handheld standards. 

### In model year 1998, two-stroke lawnmower engine manufacturers may produce 75 percent oftheirproductionbaseline. From model year 1999 until model year 2003, two-stroke lawnmowerengine manufacturers may produce 50percent of theirproduction baseline in each annual production period. Inmodel year 2003, two-stroke lawnmowerengine manufacturers must meet eitherPhase 1nonhandheld standards orPhase 2 nonhandheld standards, whichever are applicable. Although EPA's approach is not consistent with CARB regulations, which require all lawnmowers to meet nonhandheld standards with no exceptions, EPAbelieves there are two valid
reasons for the distinction. First, Congress has recognized the need for Californiato maintain its
own mobile source**~mission** control program (see section 209 ofthe CAA) because it faces difficult and distinct air pollutionproblems and, as a result, may adopt measures more stringent than those that apply in the nation as a whole. Second, EPA's nonroad emission standards are not allowed to be more stringent than is achievable afterconsideration ofcost and lead time according to section 213(a)(3) ofthe CAA Although Californiais constrainedby similarcriteria perthe authorization criteriaofsection 209 (e), consideration ofsuch criteria is limitedto the State of California. EPA must considercost and lead time when nonroad emission regulations affect the nation as a whole. EPAhas concluded that in orderfor the Agancy to meet the section 213(a)(3) requirements to considercost and lead time in setting its nationally applicable standard, it is reasonable to provide for this limitedrelieffor manufacturers oflawnmowers that use two-stroke engines. This conclusion in no way prejudges whether California should grant similarrelief. EPA agrees with commenters that four-stroke technology is generally available for lawnmowers, and that two-stroke engines are more polluting than four-stroke engines. Unlike EPA's treatment oftwo-stroke versus four-stroke snowthrowers, EPA is not distinguishing twostroke and four-stroke lawnmowers as separate products, but rather is recognizing the technological infeasibility oftwo-stroke engines used in lawnmowers meeting the nonhandheld standards by the effective date. Still, although four-stroke technology is theoretically available for alilawnmowers, it is not immediately available for manufacturers oftwo-stroke lawnmower engines, due to the cost and lead time concerns discussed above. In light ofthese concerns, EPA is providing a reasonable opportunity for two-stroke l,:\wnmowerengine manufacturers to come

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into compliance with nonhandheld standards overthe period in time during which these standards will apply.



### 3.5 Snowthrowers
3.5.1 Summary a/theProposal EPA proposed that snowthrowers meeting the handheld definition be consideredhandheld equipment; all other snowthrowers would be considered nonhandheld.


### 3.5.2 Summary a/the Comments EPAreceived comments from environmental, industry, and state and local air pollution officials' associations, and from manufacturers. In general, industry eitheropposed regulating snowthrowers for HC emissions or favored relaxed emission standards for two-stroke snowthI'owers, while environmental and state and local air officials' associations favored more stringentstandards. One industry commenter argued thatEPA should at a minimumexempt snowthrowers from

. the hydrocarbon standards, since emissions from snowthrowers do not demonstrably contribute to summertime ozone nonattainmentconcentrations.101 According to the commenter, Phase 1 accomplishes no demonstrable purpose by regulating snowthrowerhydrocarbon emissions, as snowthrowers are used exclusively during the winter and reductions achieved by regulating snowthrowers would have nobenefit for areas seeking reductions in order to attain the ozone NAAQS during the high ozone season. Industry commentedthat there are no snowthrowers with spark-ignited engines that weigh under 14 kg; 102 only electric versions are available under 14 kg. As a result, all snowthrowers

. covered by the proposal would be subject to nonhandheld standards. According to industry, if snowthrowers with two-stroke engines must comply with nonhandheld standards, EPA would effectively be banningsuchequipment andplacing an unreasonable hardship on that segmentof industry.103 One manufacturer stated that it is technically infeasible to meet nonhandheld standards. 104 Another manufacturercommented that EPA should increase the weight limit in the handheld definition to 30kg, to include snowthrowers with two-stroke engines.105 The Nonroad Study indicates that 26 percentofsnowthrowers have two-stroke engines. 106 Industry offered three main lines ofreasoning for the position that all two-stroke snowthrowers should be considered handheld: (1) Snowthrower manufacturers assumed that Phase 1 standards would mirror CARB's standards, including its special exceptions.1 07 (2) Snowthrowers do notcontribute to summerozone nonattainment, 108 In addition, because all

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snowthrowers exceed 50cc and the CO standard for nonhandheld and handheld in the over 50 cc class is the same, there wouldbe no additional airquality benefit providedby the application of nonhandheld standards to snowthrowers. 109 (3) Two-stroke snowthrowers have design, perfonnance, and operational characteristics that fill a unique market niche, and have many ofthe attributes ofhandheld equipment. 1 1 0 The unique design, perfonnance, and operational characteristics citedby industry include size, weight, maneuverability, and ease ofstorage and transport. 111 Two-stroke snowthrowers have only two wheels (neither ofwhich touch the ground during operation), and operators must provide continual support and attitudinal control byraising and tilting the equipment in order for it to perfonn. 112 Commenters noted that two-stroke snowthrowers use a 5.4 kg (12 pound) engine arid a single belt-drive system, eliminating the weight ofadditional belts andpulleys.I 13 Moreover, almost all two-stroke snowthrowers are 'single-stage,' according to comments, meaning that they
use an augerto gather snow and expel it from a single chamber. 114 Bycontrast, almost all fourstroke snowthrowers are two-stage units that use an auger to gather snow.into one chamber and a separate impellerto.discharge it from a secondchamber, according to comments.I 15 The engines in four-stroke snowthrowers weigh between 11 and 27 kg (25 and 60pounds).116 Environmental and state and local airofficials' associations opposed handheld status for two-stroke snowthrowers. 117 They expressed concern about the high levels ofunburned air toxies emittedby two-stroke engines, given operatorprox.imity.118 The associations pointed out that for larger snowthrowers, four-stroke models are available, and for the small two-wheeled version, electric models are available. 119



### 3.5.3 EPA's Response to the Comments Since EPA agreed to undertake a phased approach to smallengine regulation 

### in March 1993 (see 59 FR25399 at 25400-25401 for a detailed explanation), EPA has maintainedthat its Phase I program would be based on CARB's and incorporate the same emission standards, where it is appropriate to do so in a nationally, rather than regionally, applicable regulation. EPA is not persuaded that it was appropriate for manufacturers to assume that by adopting CARB's standards,· EPA would also adopt CARB's exceptions to those standards. Under the commenter's approach, EPA would not be able to regulate farm andconstruction equipment, solely because CARB is prohibited from regulating suchequipment under the Act. However, as discussedbelow, EPA will treat 2-stroke snowthrowers consistent with CARR

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The corrunent that it makes no difference whether snowthrowers are considered handheld
ornonhandheld, because the CO standard is the same, is moot in light ofthe fact that industry requested and is being granted various relaxations ofthe class I, II, andV CO standards. After considering the corrunents, the Agency has concludedthat the HC standard will be optional for snowthrowers. This is because, as discussed in the preamble to the proposed rule (see 59 FR at 25416) andby industry corrunents, snowthrowers are operated only in the winter, which
means that they do not measurably impact ozone nonattainment concentrations and thus need not be subject to stringent control requirements aimed at controlling ozone nonattainment. On a national level, ozone nonattainmentis primarily a seasonal problem that occurs during warm, sunny weather. Regulating HC emissions from products usedexclusively in the winter, such as snowthrowers, will not advance the Agency's mission to correct this seasonal problem. EPA recognizes that California will be regulating HC emissions from snowthrowers, and today's decision should in no way prejudice California's efforts. The Agency notes that California faces a uniquely difficult problem in that its ozone nonattainment season is yearround, and that Congress has recognized California's potential need to adopt measures that are more stringent than those that apply in the nation a whole. EPA, instead, must promulgate regulations that apply nationally in scope and that address the air quality problems that face the nation generally. Under today's rule, while manufacturers ofsnowthrowers will still be required to certify to and comply with applicable CO standards, they will be required to certify to the HC standards only where they opt to become subject to those standards. The Agency expects that many snowthrowers will in fact be certified to meet the HC standards, since the technology necessary to meet those standards will be readily available to snowthrower manufacturers and since manufacturers may wish to be able to take advantage of"green marketing" opportunities. However, the Agency does not believe it is appropriate at this time to absolutely require all snowthrowers to be certified to meet a standardthat is meant to address ambient airquality problems that do not exist when these products are in use. This decision in no way affects snowthrower manufacturer responsibilities with respect to CO standards. Moreover, ifan engine manufacturerproduces an engine that is used in snowthrowers and in other products that are not usedexclusively in the winter, that engine must be certified to the applicable HC standard. According to information submittedby industry, the weights oftwo-stroke snowthrowers range from 16.3 kg (36 pounds) to 39.9 kg (88 pounds); the average weight ofthe two-stroke models listed was 29.5 kg (65 pounds).1 20 In EPA's opinion, a product line ranging in weight from 16.3 to 39.9kg cannot fairly be considered light in weight (exceptin relation to something heavier), or specifically designed to be lifted or carried, and EPAis not inclinedto raise the weight limit in the handheld definition to 30kg to accorrunodate such equipment.

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EPA is persuadedbycomments describing the design, perfonnance, and operational characteristics oftwo-stroke snowthrowers that two-stroke snowthrowers fonn a distinct product class from four-stroke snowthrowers. As two-stroke snowthrowers are a distinct product class that depends on a relatively lighter-weight product, EPA does not consider four-stroke technology to be generally available technology for the relatively light-weight two-stroke snowthrowers. EPA shares the concerns raised by commenters about operatorproximity to high levels of unburned air toxics emitted by two-stroke engines. However, EPA lacks sufficient data to address those concerns at this time. EPA agrees with comments that two-stroke snowthrowers would meet the third prong of the handheld definition but for the weight criterion. Ratherthan amend the weight criterion in the handheld definition to include two-stroke snowthrowers, however, EPA is providing an exception to the nonhandheld standards that will require two-stroke snowthrowerengines to comply with the handheld CO standardbut not require themto meetthe HC standards, either nonhandheld or handheld, unless they opt to certify to those HC standards.



### 3.6 Use of Power Rating as Cutoff for Applicability
3.6.1 Summary o/theProposal The Agency has limitedthe applicability ofthis action to engines at orbelow 19 kW (25 horsepower) rated power. While the Age,ncy considered limiting the regulation's applicability based instead on a total displacement, it chose to propose and adopt a power-based cutofffor consistency with CARB's 25 horsepower limit. Manufacturers have generally encouraged consistency with the nonroadregulations being implemented in California, and EPAhas tried to achieve this whenever itbelieves that it is harmonious with the Agency's mission and directives.


### 3.6.2 Summary o/the Comments: The Agency is aware ofthe concern raised by STAPPAIALAPCO that the measurement of rated poweris subject to engineconfiguration and test conditions, and that a cutoffbased on power might create an incentive for manufacturers with enginesjustbelow the cutoffto change engine and/or test procedure parameters to result in a higher measured powerin orderto escape the scope ofthis regulation. 

### Intheircomments, STAPPAIALAPCO supported the one liter displacement cutoffthat EPAidentified as an alternative in its examination ofdata from Power Systems Research.121 

### Inthat study, the relationshipbetween total displacement and rated power suggests that a one-litertotal displacement cutoffwould affect nearly an identical group ofengines as a 19 kW cutoff.

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### 3.6.3 EPA's Response to the Comments Using a displacement-based cutoffwould cause a limited numberofengines to be included that would notbe included using a 19 kW cutoff(that is, engines above 19 kW but less than one liter displacement), such as some ofthe larger two-stroke engines. On the otherhand, a limited number ofengines that would have been covered under the provisions ofthe proposal would go unregulated underthis scenario (that is, engines under 19 kW but greaterthan oneliter); examples would include some ofthe larger industrial four-stroke engines. The Agency believes that the number ofengines potentially involved is small enoughto make this a marginal issue for this interim rule. Many ofthe largertwo-stroke engines that wouldhave fallen within a I-liter displacement limit would havebeenexempted from coverage in this rulebecause oftheir use in recreational vehicles. Forthis reason, and becauseEPA believes thatconsistency with the proposed CARB regulations is appropriate in this case, EPA has chosen to leave the 19 kW cutoffin place. The

. Agency will take the matter up for consideration in the Phase 2 negotiated rulemaking, currently underway.



### 3.7 Non-Coverage of Compression-ignition Engines

3. 7.1 

### Summary of the Proposal The Agency did not propose to regulate small CIengines in this action for the reasons discussed in the preamble to the proposed rule. The Agency sought commentonthis issue in its proposal because ofthe potential that unregulated CI engines could be substituted for post-control SI engines. In EPA's view, while this may occur in some cases (for example, small agricultural tractors), the mostprice-sensitive products, such as string trimmers and lawnmowers, are unlikely to shift significantly toward CIengines due to technological limitations, consumerpreference, or both.


### 3.7.2 Summary of the Comments: Both CARB and NRDCcommented that EPA should include coverage for small CI engines in this rulemaking. Expressing its concern that applying a combined HC+NOx standard only to SI engines mightcause a market shift to CIengines, CARB supported regulating both SI and CI engines in this rulemaking to effectively control emissions.I22 The NRDCcomments reiterated concerns about the effect ofdelaying standards for this group ofengines. Delaying the regulations, NRDC argued, will result in their having little beneficial impacton achieving deadlines for attainment, even in severe nonattainment areas. Since

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the states are specifically precluded from regulating farm and construction equipment, some of which employ small CI engines, NRDC has urged EPA to move quickly toestablish standards for small CIengines. In addition, NRDC pointed out that small CI engines are addressed in the CARB proposal, and says that they should be included in EPA's rule for the sake ofconsistency.


### 3.7.3 EPA's Response to the Comments TheAgency has elected not to include small CI engines as a part ofthis rulemaking. As part ofthe Sierra Club v. Browner settlement. EPA must determineby November 1996 whether to undertake a rulemaking which targets emissions from small CIengines. Small CIengines have different emission characteristics from the engines addressedbythis proposal, emitting much lowerlevels ofHC andconsiderably higher levels ofNOx than small SI engines. In contrast with its approach to this rulemaking. which is focused on achieving reductions in emissions ofHC. EPA wouldbe more likely to focus on NOx in a regulation addressing CI engines. Presently EPAlacks sufficient dataregarding baseline emissions and control technologies for nonroad CI engines in this powerrange to determine appropriate standards. To devise appropriate standards and test procedures wouldrequire that EPA undertake
a supplementary proposal. IfEPA were to gothrough the process before finally promulgating a small SI rule. it would cause EPAto miss its court-ordereddeadline for the final small SIrule and would delay promulgation ofregulations already developedfor small SIengines. Therefore EPA has chosen notto include small CIengines from this rule while working to address the issue of regulating small CI engines in a separate rulemaking.



### 3.8 Non-Coverage of Recreational Pr9Puision Engines
3.8.1 Summary o/theProposal The Agency did not propose to apply the provisions ofthis rule to engines used in recreational vehicles, examples ofwhich include snowmobiles. off-road motorcycles, ultralight planes, and all-terrain vehicles. Engines used in recreational vehicles that are not regulatedin this rule are defined by the following characteristics: use ofa continuously variable throttle (as opposed to a governor), ratedengine speeds in excess of5,000RPM, and wide variations in both engine load and speed. Because they do not qualify asrecreational vehicles underthe criteriaof this rule. golfcarts and similarvehicles that have the characteristics identified above are subjectto the emission standards set forth in this action. The Agency's primary reason for not applying this rule to engines used in recreational vehicles is the extremely transient operation ofthe products in which these engines are used. Their

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characteristically transient operation limits the ability ofthe proposed steady state test procedure to adequately represent exhaust emissions. This decision is not based on any determination that these engines do not contribute to air pollution and therefore need not be controlled. The Agency has chosen not to apply this rule to engines used in recreational vehicles in order that it may proceed quickly with a program for other small SIengines. Developing new test procedures and standards appropriate for recreational vehicles would significantly delay implementation ofstandards forthe other small engines, delaying air quality benefits, as well as causing EPAto violate the deadline for promulgation ofthis rule agreed to in the SierraClub consent decree. The Agency solicited comment on the non-inclusion ofengines used in recreational vehicles, on the criteria used to identify such engines, and on the appropriate test procedure and emission standards ifEPA were to include suchengines in this rulemaking.


### 3.8.2 Summary o/the Comments: NRDC stated that by omitting nonroad recreational engines from this rulemaking, EPA will not fulfill the requirements ofthe Clean AirAct Amendments of 1990 or the consent decree. The City ofChicago likewise was concerned with EPA's decision not to include nonroad recreational engines·in the rule. Itpoints outthat a great many vehicles with these engines are used throughout the ozone nonattainment areas surrounding southern Lake Michigan. Therefore it recommends that EPA speedily move forward on regulations to address such engines. While CARB was ofthe opinion that such engines would not have been appropriately controlled in this rulemaking, itencouraged EPAto continue studying recreational engines for future regulation. However, the Illinois FarmBureau took the position that EPA was correct in not including recreational engines in this rule and that it should not considerregulating themin any future rule. The Illinois FarmBureau's rationale is that many recreational vehicles are employed for nonrecreational purposes in agriculture.


### 3.8.3 EPA's Response to the Comments As part ofthe SierraClub v. Browner settlement, EPA will determine whether to undertake
a rulemaking which targets emissions from engines used in recreational vehicles. The Agency will
announce its intentions regarding such a rulemaking in the future.



### 3.9 Non-coverage of Marine Propulsion Engines
3.9.1 Summary o/theProposal

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### In the proposal, EPA stated that the rule would explicitly exclude from regulation small SI engines used to propel marine vessels.


### 3.9.2 Summary ofthe Comments The only commentEPA received on this matter (from CARB) was in support ofEPA's decision.


### 3.9.3 EPA's Response to 

### the Comments The Agency is not applying this rule to marine propulsionengines (examples ofwhich, in this powerrange, include outboard marineengines) because it is developing emission standards for suchengines in a separate action. The proposal for this action, publishedNovember 9, 1994,123 is also undercourt order and is currently due tobe promulgatedin November 1995. However, small SIengines used on marine vessels for purposes other than propulsion, such as generators and pumps, are subject to the provisions ofthis rule.



### SECTION 4: CERTIFICATION REQUIREMENTS AND EMISSION STANDARDS

4.1 Equipment and Vehicle Manufacturer Requirements
4.1.1 Summary ofthe Proposal EPAproposed thatequipment and vehicle manufacturers using small nonroad engines must
use appropriate handheld ornonhandheld certified engines, andprohibited the introduction into
commerce ofnonroad equipment and vehicles lacking appropriate certifiedengines after August 1, 1996. EPA also proposed thatequipment and vehicle manufacturers apply a supplemental label to the equipment orvehicle ifthe engine label is obscuredby the equipment orvehicle. EPA requested comment on a separate effective date for equipment and vehicle manufacturers, due to
concern aboutinventories ofnoncertifiedengines thatcould not beincorporated into equipment or vehicles by the effective date. Finally, EPAproposed that new replacement engines manufactured after the effective date ofthis rule be subject to this rule. EPA is finalizing these requirements.


### 4.1.2 Summary ofthe Comments EPA received commentsboth supporting and questioning its authority to require the use of certifiedengines. Oneindustry association commentedthatEPAhas no authority torequire the use ofcertified engines.124 A manufacturer and an industry association commentedthat EPA's

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authority under CAA section 213 does not extend to equipment, 125 A state, state and local air officials, and an environmental association supported the requirement that equipment manufacturers use complying engines. 126 Several industry associations commented that the prohibition on introducing into commerce equipment and vehicles lacking appropriate certified engines afterthe effective date could impose a substantial hardship on industry, and is unnecessary to prevent stockpiling;127 equipment manufacturers now minimize the period they store engines to avoid the substantial costs associated with financing and warehousing inventoried engines, according tocomments. 128 Two associations asked EPAto clarify that neitherequipment manufacturers nor dealers have any special obligation to convert their inventories to use certified engines. 129 A manufacturer asked EPAto clarify whether existing inventories may be used following the effective date. 130 

### In regard to supplemental labels, two industry associations requested that EPAclarify the meaning ofthe word "obscured," and allow the supplemental label to be less comprehensive than the engine label, consistent with California. 131 One engine manufacturer supported the requirements as proposed.132 Most**comm~nts** did not support a separate effective date for equipment and vehicle manufacturers.I33 

### An industry association commented that establishing no separate effective date is also consistent with California. 134 A state commented that a separate effective date should be based onthe date ofequipment manufacture, ratherthan the date ofintroductioninto
commerce.135 Separate effective dates recommended by a manufacturer and an industry association included six months after the effective date, 136 and February 1, 1998. 137 Onreplacement engines, an environmental association and state and local air officials support the requirement that new replacement engines for pre-1996 equipmentmeet certification standards. 138 One manufacturer expressed concern that there may be products for which a complyingengine does not exist; suchproducts would have tobe replaced in total at a much higher cost.139 

### An industry association commented that it may be unreasonable to assume that only a small percentage ofequipment will need replacementengines; itrecommended that surveys be conducted. 140


### 4.1.3 EPA's Response to the Comments EPA is finalizing the requirement that nonroadequipment and vehicle manufacturers use appropriate handheld or nonhandheld certified engines, effective with the 1997 model year. 

### In EPA's view, the most effective way to ensure that certified engines are used in nonroad equipment and vehicles is to require such engines to be used. CAA sections 213, 216, and 301 provide authority for this requirement, since EPA is required to establish standards that apply to nonroad

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engines and the vehicles in which they are used, including nonroad equipment. The definition of
nonroad vehicle, which includes nonroad equipment, is discussed elsewhere in this document. EPAis finalizing the requirement that equipment and vehicle manufacturers apply supplemental labels to their equipment andvehicles ifthe engine label becomes obscured by the equipment orvehicle. Comments in regard to supplemental labels are discussed elsewhere in this document. EPA is not establishing a separate effective date for nonroadequipment and vehicle manufacturers. EPA recognizes that certifiedengines are not likely to be available in the numbers needed by nonroad equipment and vehicle manufacturers on the effective date, and that equipment and vehicle manufacturers will continue to use noncertified engines built prior to the effective date until noncertified engine inventories are used up and certified engines are available. As long as equipment and vehicle manufacturers do not inventory engines outside ofnormal business practices (that is, as long as they do not stockpile noncertified engines), equipment and vehicle manufacturers will be considered in compliance. EPA is adding language to 40CPR 9O.1003(b)(4) to this effect Dealers have no obligation under this regulation to convert their inventories to**equip~ent** and vehicles with certifiedengines. In proposing that new replacement engines manufactured after the effective date ofthis rule be subject to this rule, EPArequestedcomment on the need for manufacturers to produce replacement engines for use in pre-1996 equipment, and the extent ofsuch a need, ifany. EPA received no information directly on point, leading EPA to deduce thatmanufacturers do not see any significant problems with this requirement. As a result, EPAdoes not believe a survey is necessary. Ifthere are pre-1996 equipment orvehicles for which a complying engine does not exist in the future, the option ofrebuilding the original engine is still available. EPA is finalizing this requirement as proposed.



### 4.2 Engine Family Definition
4.2.1 Summary of the Proposal The Agency proposed using the criteriafor determining engine families as are currently used for on-highway motorcycles: combustion cycle, cooling mechanism, cylinderconfiguration, number ofcylinders, engine class, and the number, location, type, and thermal reaction characteristics ofcatalytic converters. Comment was solicited on adding governed RPM range as a criterion for determining engine family, because ofa concern that a wide-governedrange in the
sameengine family may result in unrepresentative emission test results.

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labeling requirements so that a single label could meet the requirements ofboth programs.145 Industry commenters expressed general concern that the labeling requirements are excessive, and that the cost burden would notbejustifiedonthe basis ofneed. Othercomments centered onthe requirement that equipmentmanufacturers attach a supplemental label identical to the original ifthe original is obscured.146 Several commenters also stated specifically that the unique engine identification number requirement was costly and unnecessary.l47


### 4.3.3 EPA's Response to the Comments The Agency has decided to retain the provision requiring equipment and vehicle manufacturers to apply a supplemental label to the equipmentorvehicle ifthe original label is obscured. This provision is compatible with CARB, and ensures that owners, dealers, and fepair

.personnel will have access to necessary engine information without disassembling the original vehicle orequipment. After considering the comments, the Agency has decided to provide manufacturers with additional flexibility in the labeling requirement. To reduce manufacturerburden and provide compatibility with CARB, EPA will accept a label that has been approvedbyCARB thatcontains language indicating-that federal standards have alsobeen met. TheAgency will accept the following: 1) a harmonized CARBIEPA label for 50-state engine families, 2) a CARB label with additional language saying it meets federal standards for the 49-state label, and 3) the EPAproposed labeL In addition, the Agency has dropped, the unique engine identification number requirement. Based oninformation suppliedbyengine manufacturers and their associations,148 EPAdetermined that the information to be gainedby requiring the unique number did notjustifythe additional capital and administrative costs to the manufacturers. Because no useful life time period orin-use standard is beingestablished, the Agency has decidedto allow in-use testing and recall on a voluntary basis for Phase 1and, as a result, there is no need for EPA to require the unique engine identification number.



### 4.4 Cap on Noise
4.4.1 Summary of the Proposal The Agency proposed that noise levels ofsmall SI engines notbe allowed to increase as a result ofthe new emission standards. In proposing the small SIengine regulations, EPA did not expectthatengine noise levels wouldbe affectedbythe type ofengine changes it anticipatedtobe necessary to meet the proposed gaseousexhaustemission standards. The primary source ofnoise

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from nonroad small engines originates from combustion andthe moving parts in the engine, such
as the piston, valve train, and so forth. Noise from combustion is controlled primarily through the engine muffler. The Agency believes the principal method that will be used by all engine manufacturers to meet the proposedemission regulation will be leaner air/fuel ratios. Therefore, it proposed that noise levels in future engines which meet the new standards must not exceedthat of current production engines. The Agency requested commenton the possible impact ofthe proposedregulation on engine noise.


### 4.4.2 Summary ofthe Comments A concernedcitizen stated that EPA should control noise emissions from small engines, arguing that the noise such engines generate cancause stress. Thatcommenter specifically urged EPAto use its authority to regulate noise under section 213(a)(3) ofthe Clean Air Act and under the Noise Control Act of 1972, 42 U.S.c. 4901-4918.149,150 Injointlypreparedcomments, ST APPA andALAPCO statedthat they are not convinced that the noise cap is necessary, because they do not believe there is any significant likelihood that noise levels will beaffected. Indeed, nocommenter submitted any information supporting the contention that noise levels could increase as a result ofthe Phase 1regulations. However, were EPA to go ahead with its proposal tocontrol noise. STAPPA and ALAPCO were concerned that EPAhad not proposedrequirements by which itcould determine compliance with a noise cap. Onan, EMA, OPEl, andTecumseh stated that EPA should drop the requirement that noise not increase. ECHOrequested that EPAmodify its proposed requirement on noise to readthat "sound levels shall not increase overthe current allowable standards (ifapplicable) for the equipment types."151 PPEMA questioned EPA's authority to impose noise caps and recommended thatEPA delete this requirement. Tecumseh stated that engine and equipment manufacturers already adhere to voluntary noise standards associated with specific test procedures. 152 They saidthey do so because the public demands it, and they believe that their desire to be responsive to the public will assure that noise levels do not become problematic after this rulemaking becomes effective.


### 4.4.3 EPA's Response to the Comments While EPA does believe that engine noise shouldbe controlled, it has notpromulgated noise control regulations in this rulemaking for three reasons: (1) it needs more information concerning noise impacts from small SIengines before imposing noise standards, (2) it did not propose a test procedure to be used for determining compliance with any noise standards it might set, and (3) as noted previously, the industry is already self-regulating to a degree.

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While it is aware that some noise standards for specific equipmentexist such as the European Economic Community's noise standards for lawnmowers. EPA lacks the necessary information to determine whether it is reasonable at this time to impose engine noise regulations without regard to the type ofequipment in which the engines will eventually be used. For example, the fact that Europe is regulating lawnmowers rather than engines indicates that noise may be mostly equipment-specific. Continuing with the example oflawnmowers, it appears that the majority ofthe noise may be from the blade and othernon-engine components ofthe equipment. Moreover, EPA has recognized that it would not be sufficient for it to simply establish a requirement that noise not increase without providing some standardized procedure for making such a demonstration. The Agency did not provide a test procedure for assessing noise in the NPRM. Because no opportunity for comment on a specific test procedure for noise was given, EPA recognizes that promulgating a regulation requiring such a test would not be appropriate in the Phase 1rule. Nevertheless, EPA strongly supports engine and equipment noise controls. Itcommends the efforts at self-regulation already undertaken by manufacturers; however, ifEPAbecomes aware ofnoise increases in conjunction with the entry ofPhase I engines into use, it may address this issue in a future regulatory action.



### 4.5 Safety Implications
4.5.1 Summary of the Proposal The Agency made no proposal regarding safety (except as related to noise control, discussed above).


### 4.5.2 Summary of the Comments ECHO commented that the impact ofthe proposedregulations on product safety was not yet clearl53

. PPEMApointed outthat several safety standards apply to many handheld productsl54 and asked EPA to considerthe safety implications ofthe Phase 1regulations before promulgating them.


### 4.5.3 EPA IS 

### Response to the Comments The Agency encountered no information in its investigations that indicate to it that negative implications for safety will arise as a result ofpromulgating these regulations. Nocomments offered any substantiation supporting the ideathat there may be problems related to safety arising

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from this rulemaking. 

### IfEPA finds evidence that safety may be compromisedby this action, it will reopen the issue.



### 4.6 Retention of Certification Engine
4.6.1 Summary of the Proposal The proposal was silent regarding the manufacturer's responsibility to maintain any test engine used for data submittal afterthe certification process has been completed.


### 4.6.2 Summary ofthe Comments PPEMArequested that EPA allow manufacturers to retain the original certificationengine for running change testing. 155


### 4.6.3 EPA's Response to the Comments The Agency does not require engine manufacturers to maintain test engines after a certificate has been granted. However, EPA agrees that the manufacturer may find ituseful to retain certification engines for future data showings to EPA, especially in back-to-back testing to support approval ofrunning changes.



### 4.7 CO Standard
4.7.1 Summary ofthe Proposal EPAproposed the CO emission level of402 glkWh for Classes I, II and V.


### 4.7.2 Summary ofthe Comments The CO emission levels for Classes 1, II and V were objected to by several associations due to technical feasibility for some classes ofengines to meet the proposed standards. EMAlOPEIrecommended that the CO levels for Classes I and IT beraised from402 glkWh to469 glkWhbased on the argument that it is nottechnologically feasible for a significant percentage ofthe market to meet the more stringent standard. Airto fuel ratios requiredcause inuse performance problems, according to the comments; EMAlOPEI supplied a lengthy rationale for raising the CO standard for engines marketed to the mass merchant (see Preamble discussion).

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PPEMA requested that the CO level for class V engines be changed from 402 glkWh to 603 glkWh based on technical feasibility ofreaching the standard without excessive temperatures that create product durability problems.


### 4.7.3 EPA'S Response to the Comments In response to EMNOPEI's recommendation, EPA has changed the COlevel from 402 glkWh to 469 glkWh for Class I and Class II. EPA chose to change the CO level from 402 glkWh for Class IT even though the only available data in the RIAlRSD for Class II (Table 1-15) showed that the engines in Class II currently are below the proposed CO level. This is based on confidential information from one engine manufacturer which illustrated that there is a wide spread ofemission results due to engine to engine variability. Theirexperience, from a much larger number oftests, showed that there are still a large numberofemission results above the CO standard. Research is underway to optimize cylindercooling designs and to improve fuel distribution which could allow further CO reduction without overheating engines in the future. However, based on the amount ofwork shown to have been done on improvements to date, EPA has determined that insufficient time is available to advance fuel system and cooling system technologies to**achi~ve** the proposed CO emission levels. 

### An increase in the CO emission standard will not impact the feasibility ofthe HC+NOx standard. This is based on the fact that changes in COemission levels are directly related to the operating NFratio ofthe engine alone. There are a number ofHC and NOx emission control strategies available, such as optimizedcombustion chamberdesign, which are independent ofCO emission levels.

ForClass V handheld engines, EPA has published datain Table 1-19 in the RINRSD which shows that approximately 20 to 30 percent ofthese engines (Class V) meet the 402 glkWh CO standard through enleanment ofthe engine. However, four pieces ofinformation (out ofthe

. eight that showed emission levels below 402 for CO) are from four production engines ofthe same engine design from one manufacturer. EPA has considered submittedcomments from PPEMA and reviewed the information in Tables '1-16 and 1-17 in the Phase I RIAlRSD. EPA has no datato support the required higher reduction in perengine CO emission levels proposed for Class V engines than for Classes III and IV. Thepresent CO standard of804 glkWh for Class IVengines results in a reduction of3.7 percent from the average ofbaseline Class IV engineemission levels in Table 1-16 (Datafrom the one Class illengine already meets the CO standard). Theproposed CO level of402 glkWh for Class V engines results in a 42 percent reduction from the average ofbaseline emission levels in Table 1-17, much higher than the 3.7 percent reduction required from Class IV engines. Bychanging the COlevel to 603 glkWh, EPA would bring the Class V reduction (now 13 percent) in line with the CO reductions in Class IV

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engines. This change provides a more level playing field, by providing similar reductions across Class IV and V engines. The adjusted CO levels provide reasonable emission standards which the manufacturers can achieve and thereby minimize the concerns with operation at much leaner levels at this time. Phase II emission standards will address the possibilities offurther enleaned engines
across all engine classes. PPEMA has not requested the same change in CO level from CARB due to the fact that nearly all ofthe equipment in this class ofengines is exempted from CARB regulations due to the definition offarm and construction equipment.

The impact on the decreased CO emission benefits, based on alterations in the CO levels for Classes I and V, are included in the table below. (Additional changes to the model have been made and therefore the emission benefits cannot be directly related to those values published in the RIA for the Phase I NPRM.) The total change in COemission inventory from baseline is 2.3 percent with changes to Class I and Class V. The difference in emission benefits for Class V is small compared to the change from Class I due to the fact that the sales volume in Class V is significantly less than the sales in Class I. Therefore, the 201 glkWh increase for Class V is less ofan impact than the 67 glkWh increase for Class I.

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CO EMISSION INVENTORY CHANGE (yr 2020) NPRM ANAL RULE BASELINE WICONTROL % BENEFIT BASELINE WICONTROL**%BE1~EAT** CLASS I only 12,995,551 11,168,720 14.4 12,995.551 11,405,697 12.2 CLASS II only 12,995,551 11,168,720 14.4 12,995,551 11,850,062 8.8 CLASS V only 12,995,551 11,168.720 14.4 12,995.551 11,212,098 13.7 CLASS I,ll & 12,995,551 11,168,720 14.4 12,995,551 12,130,398 6.66 V



### 4.8. Class V Compliance Margin Language 4,8.1 Summary of the Proposal EPAproposed that the 402 glkWh CO standard is feasible for Class V because test data indicates that approximately 20to 30percent ofClass V engines already achieve average CO levels ofeightpercent below the standard. (see Table 1-19 in the RINRSDfor Phase I Small SIEngine**Reg~lation).** 

### 4.8.2 Summary of the Comments PPEMA states that the 8 percentcompliance margin suggestedby EPA does not provide adequate statistical assurance that all engines will meetthe standard. The variability inherentin the production process requires an average compliance margin that is substantially higherthan 8 percent, according to PPEMA. PPEMA argues that EPAunderestimates the number ofengine models that must be broughtinto compliance.


### 4.8.3 EPA'S Response to the Comments No additional datawas suppliedby PPEMA to change the compliance margin from that calculated from the available data. Since EPA's NPRMwas published, a large numberof Californiaengine models have been certified. Although Class V engines are largely exempted in California, the new Class 

### illand IV emissions dataprovide importantinformation onjusthow large a safety margin manufacturers are certifying to in orderto ensure the entire engine model will stay below the CO standards in production. These data would suggest a larger margin than the 8 percent providedby the proposed CO standard is needed. EPA's action to change the proposed CO standard from 402 glkWh to 603 glkWh for Class V engines will result in a higher compliance margin.

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### 4.9 He 

### + NOx Standard
4.9.1 Summary ofthe Proposal The Agency requested comment on two proposals for setting Class I and II HC andNOx standards. Option 

### I consists ofsetting a combined standard for emissions ofHC and NOx for Class I and II engines. Under option 2, EPA would set separate HC and NOx emission levels for Class I and II engines.


### 4.9.2 Summary ofthe Comments CARB statedthat ifEPA sets separate standards, CARB encourages the choice of standards to reflect CARB standards of 12 glbhph and 10 glbhph for Class I and II engines respectively, thus allowing manufacturers to market a single engine family nationwide. Onan is opposed to separate standards. Ifseparate standards are promulgated, a substantial amount oftesting will need to go into determining the appropriate levels ofthe two exhaust constituents. NRDC supports separate standards and at a minimum requests a requirement ofseparate reporting. Wisconsin accepts the combined standard with reservations for Phase I only, and wants separate reporting ofHC and NOx emissions in all Phase I testing and compliance programs. Tecumseh supports combined standards. STAPP A supports a combined standard for Phase I only andrequests a separate reporting ofHC and NOx. STAPPA saw an environmental benefit ofseparate standards since such a structure would limit interpollutant trading with a separate NOx standard.


### 4.9.3 EPA'S Response to the Comments EPA has considered all ofthe comments and has decided to keep the HC+NOx standard and add the requirement ofseparate emission value reporting for HC .and NOx. This will serve two purposes in allowing the manufacturers the flexibility in using technologies to reduce emissions from small engines and provide states with the detailed information needed for modeling ofpollutants and SIPplanning. The combined HC+NOx standard for Phase I is in harmony with CARB. EPAdoes not considerthe combinedHC+NOx standard a precedent for use in Phase II small SI engine regulations. In addition, this measure is only effective for a short number ofmodel years before Phase II wouldcome into effect.



### 4. 10 Stringency of Standards

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4.10.1 

### Summary of the Proposal EPAbelieves that the proposed Phase 1emission standards are the lowest standards for Class 

### I-V engines achievable by the 1996 model year.
4.10.2 

### Summary ofthe Comments Onan stated that ifthe proposed Phase I emission standards are the lowest standards for Class 

### I-V engines by the 1996 model year, then the emissions limits should be higher than those proposedby 20percent or so. Manufacturers will set theirproduction emission limits well below the standard to assure thattheirproducts meet the standard, given manufacturing tolerances.

NRDC statedthat the statutory requirements and language for nonroadengine standards at section 213(a)(3) ofthe Act are comparable in stringency tothe section 202(a)(3)(A) motor vehicle emissions standards, which also require standards that achieve "the greatest degree ofemissions reduction achievable." Thus the Act requires EPA to determine the"degree ofreduction" for nonroad engines basedon its comparable standards for onroad motor vehicles, and to consider the stringency and lead-time ofonroad standards as the basis for establishing standards under section 213.
4.10.3 

### EPA'S Response to the Comments In response to manufacturer comments with respect to productiontolerances and their impact on emission standards, EPA is well aware ofthe need for what has come to be known as "headroom." This is the level the standards mustbe set at to allow engine models to bebuilt reliably incompliance. EPAhas proposed an appropriate effective date that would allow engine manufacturers to make the technical changes that allow their engines sufficient headroom to meet the emission standards. EPA acknowledges that automobile engines have been made to achieve greaterdegrees of emission reductions than are presently requiredby this rulemaking. However, since this is the first requirement for small engine manufacturers to reduce emission levels, EPA has split the emission reductions required into two phases with the second phase ofemissionregulations to come after the first phase. The first phase ofregulations will require moderate to extensive improvements in engine designs with some catalystusage possible. The second phase ofregulations may require
more advancedtechnologies which are currently under development for application on a majority ofthese classes ofengines. EPA has decided to adopt most ofthe standards as proposed with changes to only the CO standards for Classes landV (see response to comments on this issue).

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### 4.11 Regulating HC vs. VOC
4.11.1 Summary of the Proposal The Phase I NPRM stated that volatile organic compounds (VOCs) are compounds containing carbon and hydrogen in combination with any otherelementwith a vapor pressure equal to orgreaterthan 1.5 pounds per square inch under actual storage conditions. HCs therefore, are a subset ofVOCs. Based on the testing indicating that HC emissions represent VOCs from small SI engines that cause orcontribute to ozone nonattainment concentrations, EPA proposed an HC, rather than a VOC standard.


### 4.11.2 Summary ofthe Comments Onan statedthat it supports regulating HC based on the fact that present emission measuring equipment is not capable ofmeasuring VOC and appropriate equipment is a sizeable cost to small engine manufacturers. SwRI has shown that 99 percent ofVOCs emitted from engines coveredby this NPRM are HCs and CARB regulates HC (harmonization). EMA and OPEl support this aspect ofEPA's proposal. EMA stated that HCs make up
more than 99 percent ofthe VOCs emitted from small engines. Inasmuch as the types ofcontrols used to reduce HC emissions likewise will reduce emissions ofother VOCs, setting emission limits for HC emissions should essentially accomplish the same reduction in VOC emissions as would be achievedby setting limits for VOCs.


### 4.11.3 EPA'S Response to the Comments EPA is setting standards for HC regulation.



### SECTION 5: TEST PROCEDURES AND EQUIPMENT



### 5.1 Certification Test Fuels
5.1.1. Summary ofthe Proposal The proposedrule allowed for the use ofone test fuel for certification, the parameter specifications and tolerance levels were specified in an Appendix to SubpartD.


### 5.1.2. Summary ofthe Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-43­

The Kohler Company stated concerns that the proposed fuel specifications were too tight and the fuel would not be readily available. Kohler suggested that the Agency relax the tolerances
sothatrecognized certification fuels such as Indolene Clear would be acceptable. Qnan Corporation questioned what fuel was being specified. Qnan suggested that the Agency add language that would allow future California and Federal on-highway certification fuels be used for small engine certification. The Portable PowerEquipment Manufactures Association (PPEMA) stated that the proposed fuel tolerances were too stringent. They voiced concerns regarding fuel availability, particularly in foreign countries. PPEMA suggested the Agency's rule be consistent with CARB and SAEJ1088, and asked that EPA allow the use ofIndolene Clear. PPEMA also suggested that

. EPA allow the use ofcomparable, commercially available fuels in foreign countries where the engine is manufactured and tested for certification.


### 5.1.3. EPA's Response to the Comments The fuel specified in the proposed rule was meantto represent typical commercially available gasoline available in the U.S.A. Afterpublishing the proposal the Agency discovered the fuel tolerances specified in fact were too stringent. The tolerances have been increased and the Agency believes the fuel can be purchased from many refineries in the U.S. Because ofthe importance offuel parameters to emissions testing, the Agency does not believe commercially available fuels in foreign countries are acceptable for certification testing unless the fuel meets the specifications in the regulation. In addition,- the Agency has added an additional fuel as a possible certification fueL The Agency has added the specifications for the certificationfuel used for onhighway gasoline fueled light-duty vehicles, specified in 40CFR 86. 1313-94(a). This fuel is commonly referred to as Indolene Clear.



### 5.2 - Service Accumulation Fuel (or Break-In Fuel)
5.2.1. Summary of the Proposal The proposal specifies thatthe Service Accumulation Fuel must be representative of commercially available fuel. The proposal also states that the Reid VaporPressure ofthe fuel be typical offuel in use for the time ofyearthe engine is tested.


### 5.2.2. Summary of the Comments The Kohler Company and Qnan Corporation requested thatcertification fuel be allowed for
use as the service accumulation fuel as an alternative to commercially available fuel.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-44­

Onan also commented that it would be more appropriate for the RVP ofthe fuel to be typical ofa summertime grade fuel, since most small engines are used in the summertime. Echo Corporation suggested that the service accumulation fuel**~quirements** be altered to include fuel which is characteristic ofthe country's motorfuel because U.S. fuel is difficult to import into foreign countries.


### 5.2.3. EPA's Response to the Comments The Agency specified a commercially available fuel as an alternative to the certification fuel
as a method oflowering manufacturers cost due to the generally high costofcertification fuel. However, the regulation has been changedto include the certification fuel as an option for the service accumulation fuel. The RVP specifications have also been altered to allow the use ofa summertime fueL For foreign manufacturers, the Agency is not proposing that the service accumulation fuel mustbe from a U.S. refinery, only that the fuel be representative offuel commercially available in the U.S.



### 5.3 Power Measured During the Idle Mode
5.3.1. 

### Summary of the Proposal The proposalrequired that power measured during the idle mode ofthe proposed test cycles should not be included in the calculation ofthe weighted brake-specific emission rate.


### 5.3.2. Summary of the Comments Onan Corporation suggestedthat the Agency should include the windage power measured during the idle mode. Onan stated that to not include the windage powerwouldbe to unjustifiably increase the mode weighted emission values. The Echo Corporation proposed that the Agency should allow the use ofidle power in the weighted calculations only ifthe piece ofequipment the engine is used inproduces work while idling. PPEMArequested that the Agency remove the idle mode completely from Cycle C, the handheld test cycle. 

### Ifthe Agency decides to leave the idle mode, manufactures should be allowed to include the power measured during the idle mode in the emission calculations.


### 5.3.3. EPA's Response to the Comments The Agency has basedthe form ofthe emission standards for this rule and otherengine rules in terms ofbrake-specific emission rates, ie. mass ofemissions perunit time perunit power. The rationale behind this is to base the standardin terms ofthe amountofuseful work performed

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments oil the NPRM 5127/95-45­
by the engine. During the idle mode an engine is producing the amount ofwork necessary to maintain idle speed, therefore no external work is generated. Forthis reason, any power measured during the idle mode portion ofthe test is a result ofa load applied to the engine from the power measuring device and should not be included inthe calculations ofthe weighted brake-specific emissionrates. The manufacturer always has the option ofdisconnecting the engine from the dynamometerfor the idle mode. For these reasons the Agency will not be altering the final rule in response to this comment. The Agency will not be removing the idle mode from test Cycle C.



### 5.4 Differences between the proposed Federal test procedure and the Society of Automotive Engineers (SAE) Recommended Procedure J1088.
5.4.1. Summary of the Proposal The proposed test procedure is based primarily on the heavy-duty gasoline engine test procedure detailed in Title 40ofthe Code ofFederal Regulations, Part 86, Subpart D. 4OCFR86 Subpart D is a certification test procedure for heavy-duty diesel and gasoline on-highway engines.


### 5.4.2. Summary ofthe Comments The Qnan Corporation stated thatthe Agency must demonstrate a lack ofuniformity between test laboratories orthe proposed changes from established test practices should be considered arbitrary and capricious. Qnan mentioned an industry sponsored correlationprogram
run by the Engine Manufacture Association (EMA) which showed good correlationbetween four engine manufactures, one component manufacture, EPA, and the University ofMichigan. PPEMA stated that the Agency's proposed modifications to SAE 11088 do not meaningfully increase the measurement precision orconfidence in the prediction ofemission reductions. Furthermore, PPEMA contends that given the demonstrable accuracy ofthe SAE 11088 procedure, the Agency's proposed changes only increase the costto manufactures and are notjustified.


### 5.4.3. EPA's Response to the Comments The Agency has very little data with which to compare small engine manufacturertest laboratories. There are overthirty engine manufacturers who sell engines inthe U.S. who may want to certify engines to this rule ifthey wish to continue selling engines. To use the data from a single round-robin test program which only included four out ofat least thirty engine manufactures does not appearresponsible to the Agency.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95No engine manufacturer submitted data or information on the "demonstrable accuracy" of the 

### J1 088 procedure, or on the incremental costs to manufacturers which may 

### be attributed to the differences between the SAE

### J 1 088 procedure and the proposed rule. The burden is not on the Agency to disprove a recommended test procedure. EPA did not
use the 

### J1088 procedure as a starting point for the proposed test procedure. The test procedure is basedprimarily on existing EPA certification test procedures for otherengines which are currently regulated, primarily heavy duty diesel and gasoline on-highway engines. The SAE

### J1088 is a recommended test procedure whichby itselfthe Agency does not feel is appropriate for certification testing.



### 5.5 Unconditioned Air Supply, Humidity Measurement
5.5.1. Summary of the Proposal In §90.310 ofthe proposal, there is a requirement that engines with humidity conditioned air supplies must measure the humidity ofthe air in the engine's intake air system.


### 5.5.2. Summary of the Comments The Onan Corporation suggested the paragraph 

### be revised to allow the measurement ofthe test cell humidity for those engines which don't have humidity conditioned air supplies. Echo Corporation suggested the paragraph

### be deleted, since small engine manufactures don't pre-condition the intake airgoing into the engine.


### 5.5.3. EPA's Response to the Comments The final rule has been altered to allow the measurement oftest cell humidity for engines which do not use humidity conditioned air supplies.



### 5.6. Test Conditions, Test Engine Orientation
5.6.1

. Summary of the Proposal

.The proposal required that Class I and II engines must be level during the emission test.


### 5.6.2. Summary ofthe Comments OnanCorporation suggested changing the requirement so that 

### all engines must be tested at their design angle.


### 5.6.3. EPA's Response to the Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/9547­

The suggestion made by Onan is appropriate for small engines, since many small engines
are not designed to operate in a level position. The fmal rule has been modified accordingly.



### 5.7. Ambient Test Conditions and f-parameter Specifications
5.7.1. Summary of the Proposal Theproposedregulations require that the test cell temperature (T) and dry barometric pressure (Ps) are used in the calculation ofa "f-parameter" according to the following formula

= 

### 101.3 

# (-1:....)0.7 f 

### P. 

## x 298 

### In orderfor a test tobe valid the value ofthe f-parameter mustfall between the values of0.98 and 1.02. 

### In addition, the regulations require thatthe ambienttestcell temperature bemaintained between 20° and 30° C.


### 5.7.2. Summary of the Comments Onan Corporationcommented that Ix>th the formula and the limits for the f-parameter are too restrictive and the dry barometric pressure standard of 101.3 kPain the formula for 

### "f' is too high. Upon request, Onan submitted additional datacontaining daily drybarometric pressure minimum and maximum values for their lalx>ratory from September 1991 to December 1993. This data shows that ifthestandardpressure is setat 101.3 kPa, Onan would be unable to perform a valid test approximately 85% ofthe year, ifthe standard pressure is set at99 kPaOnan would be unable to test on approximately. 10% ofthe year, and ifthe standard pressure were changed to 97 kPa, Onan would be able to testevery day. These calculations assume testcell temperature canbe variedbetween the proposed limits of20° and 30° C. Onanrequested that the Agency either eliminate the f-parameterrequirement orchange the limits orthe standardpressuretoallow manufactures to test on the majority ofthe year. PPEMArequested an ambient test cellrange of 15-30C. PPEMAstated that the fparameter serves only as a correction factor for potentially different test conditions. Temperature andbarometric pressure are considered in engine powercorrections. PPEMArequested the proposed f-parameter restrictions beremoved.


### 5.7.3. EPA's Response to the Comments 

### In a preliminary draft ofthe testprocedure, for whichEPArequested a technical reviewby the SAE Small Engine andPoweredEquipmentCommittee inJuly of 1993, the f-parameter standardpressure was 99kPa, not 101.3kPa. 

### In the comments from one ofthe SAEreviewers, EPA was requested to change the standard pressure to 101.3kPato be consistent with the standard

Emission Standards for New-Nonroad Spark·Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-48­

pressure used for volumetric flow rate calculations in the regulations. Since thattime the Agency has received verbal commentfrom the SAE reviewer stating that they made an error in their review and would preferthat the standard pressure for the f-parameter calculation be set to 99k.Pa. This correction has been made to the final rule. The purpose ofthe f-parameter for this rulemaking is to insure that all manufacturers perfonnthe certification test under a set ofrestrained ambient conditions. TheAgency does not have any infonnation at this time regarding the effects ofbarometric pressure and temperature on small engine emission perfonnance. 

### Ifin the future scientific data are produced which show the relationship between ambient cell temperature, barometric pressure and emission perfonnance, the Agency would consider issuing a technical amendment to the regulations altering the f-parameter and ambient cell temperature limits appropriately. TheAgency is also aware ofthe burden placed
on manufacturers by what may be unnecessarily stringent f-parameter tolerances. The proposed allowable tolerance band was

## ±two percent, the Agency has increased the allowable tolerance band for the final rule to 

### ± four percent, from 0.96 to 1.04.


### 5.8 Oxygen**I~terference** 

### Check - Frequency of Check


### 5.8.1. Summary of the Proposal The proposal states that an oxygen interference check must be perfonnedas part ofthe hydrocarbon analyzer calibration in §90.316. The calibration frequency for the oxygen interference checkis not spelled out. 

### 5.8.2. Summary ofthe Comments Onan Corporation requested infonnation on when and how often the oxygen interference checkmustbe perfonned.


### 5.8.3. EPA's Response to the Comments In Table 2 ofAppendix A ofSubpart D, the calibration frequency for the hydrocarbon analyzer, which includes the oxygen interference check, is monthly. Theregulation has been changed toexplicitly spell out this requirement in §90.316(d).



### 5.9 Carbon Monoxide Analyzer Interference Check. 

### 5.9.1. Summary of the Proposal The proposal requires that manufacturers periodically (within one monthprior to the certification test) perfonna check on the response ofthe carbon dioxide NDIR analyzer to water

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM

. 5/27/95-49­

vapor and carbon dioxide. The method was described in the proposal, and it involves bubbling a mixture ofC02 and nitrogen gases through water which is then read by the analyzer.


### 5.9.2. Summary ofthe Comments Onan Corporation requested that manufacturers be allowed to perform a dry carbon dioxide interference check, or at the very least, allow the mixture to be introduced into the sample priorto the watertrap.


### 5.9.3. EPA's Response to the Comments The purpose ofthis interference check is to examine the analyzers response to both carbon dioxide and to water vapor. TheAgency's experience led to the developmentofthe procedure described in the proposal, and this language was not altered for the final rule.



### 5.10 Calibration Frequency
5.10.1. Sum'!"lry of the Proposal The proposal states thatcalibrations for several instruments mustbe performed monthly.


### 5.10.2. Summary ofthe Comments Onan Corporation suggests that EPA should only require calibrationintervals withrespect to certification oraudit equipment. In addition, Onan suggested that instead ofrequiring monthly calibrations on instruments, the requirement shouldbe thatthe instrument must have been calibrated within one month priorto the certificationtest.


### 5.10.3. EPA's Response to the Comments The Agency agrees with Onan's suggestion regarding calibration frequency. The proposed language was taken from on-highway certification testprocedure documentation where manufacturers are performing certification tests routinely throughout the year. If a manufacturer does not run certification tests throughout the year, for instance the tests are run during a six month period, it would notbe necessary for the manufacturer to performmonthly calibration on instruments which are not used for the remaining six months ofthe year. This wouldplace a burden on the manufacturer which has no technical benefit. The regulation language has been changedfrom requiring a monthly calibration frequency to requiring calibration within one month ofthe certification test.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-50­


### 5.11 Test Procedure Overview, Dynamometer Requirement
5.11.1. Summary ofthe Proposal The proposal requires a dynamometer be used as the engine loading device for the certification test.


### 5.11.2. Summary ofthe Comments Onan Corporation requested that EPA change the requirement that a "dynamometer" must be used as the engine loading device for the engine test cycle to an "engine load measuring device."


### 5.11.3. EPA's Response to the Comments The Agency agrees with OQan's suggestion. It is not necessary to use a dynamometer if another instrument which canperform the same function is available. The final rule has been changedto allow the use ofan engine load measuring device to perform the engine test cycle, as long as the alternative device meets the necessary speed and torque accuracies specified in the rule.



### 5.12 Recorded Information, Explanation of Terms
5.12.1. Summary of the Proposal The proposed rule requires manufacturers torecord the "date ofmost recent analytical assembly calibration" under the general test records section.


### 5.12.2. Summary ofthe Comments Onan Corporation requested that EPA give a definition ofwhat the "date ofmost recent analytical assembly calibration" refers to.


### 5.12.3. EPA's Response to the Comments The proposed language was not clearon what the analytical assembly referred to; the final rule has been changed to read "date ofmost recent analyzer bench calibration."



### 5.13 Humidity and temperature measurement of engine intake air
5.13.1. Summary of the Proposal Theproposal requires the measurement ofengine intake airtemperature, and the measurement ofintake air humidity for those engines whose intake air humidity is pre-conditioned.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-51­



### 5.13.2. Summary ofthe Comments Onan Corporation suggested that intake air humidity and temperature measurements should not be required. Onan suggested that ambient test cell conditions should be allowed instead, particularly for humidity.


### 5.13.3. EPA's Response to the Comments The Agency believes that engine intake air temperature should be a simple measurement for manufacturers to make. Measurement ofengine intake air humidity is only required for engines with pre-conditionedintake air, otherwise the ambient test cell humidity measurement is sufficient.



### 5.14. Engine service accumulation time determination
5.14.1. Summary of the Proposal" In §90AOS, the proposal provides the manufacturer with two options regarding service accumulation on the certificationengine. First, the manufacturer can make a determination, for each engine family, the appropriate service accumulation time necessary for the stabilization of emissions, butthis time may not exceed 12 hours. As an alternative, the manufacturer can use 12 hours as the service accumulation duration without conducting an engineering determination. However, in §90.11S, the second option is not mentioned.


### 5.14.2. Summary ofthe Comments Onan Corporation stated that the engine manufacture shouldbe allowed to choose any break-in procedure they choose. PPEMAbelieves the Agency's proposed 12 hourbreak in time is unnecessarily long. Echo Corporationrequested that ifa manufacturercandemonstrate that an engine emissions are not stablebut are decreasing; the manufacturer shouldbe allowed to test the engine at that point.


### 5.14.3. EPA's Response to the Comments EPAbelieves that at least part ofthe misunderstanding regarding this subject was the discrepancy between §90AOS and §90.11S. Section §90.1IS has been changedto match §90.40S. A manufacturercanchoose to make the service accumulation time determination orthey may use 12 hours as a.default, but the selfdetermination time may not exceed 12 hours. The final rule has also been modified to accept the suggestion by the EchoCorporation regarding engines with decreasing emissions. Ifa manufacturer can demonstrate that an engine family's emissions, including all regulatedpollutants, are decreasing from some initial time (greater than zero but less

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-52­

than 12 hours) outto 12 hours, the manufacturer will be allowed to stop the service accumulation at the time where emissions begin to decrease.



### 5.1 5 Effect of emission measuring equipment on engine performance
5.15.1. Summary ofthe Proposal The proposal requires the manufacturerto run the test engine at a single speed and torque point bothbefore and after the emission sampling equipment is installed. The engine's power, and for raw gas sampling, fuel consumption, are measured in both instances and should agree within approximately five percent.


### 5.15.2. Summary ofthe Comments Onan Corporation requested that manufacturers should be allowed to performthis check after the certification test, ifat all. Manufacturers should not have to performthis onevery certification test; demonstration on similaror worst case setups should be adequate.


### 5.15.3. EPA's Response to the Comments Manufacturers are required to performthis checkpriorto the certification test sothat ifa problem is found itcanbe corrected before the certification test is run. This test should not be confused withthe service accumulation and should be done after the service accumulation is complete. The Agency does notbelieve it is a significantburden for manufacturers to run this simple, two mode test, one priorto and one after the emission sampling equipmentis installed. This test only requires the measurement ofat most three parameters, engine speed, torque and fuel consumption.



### 5.16 The use of observed vs. corrected torque in power calculations
5.16.1. Summary of the Proposal Theproposal requires manufacturers to use observed torque in the calculation ofengine power. 

### 5.16.2. Summary ofthe Comments Onan Corporation requested that EPA use corrected torque, not observed.


### 5.16.3. EPA's Response to the Comments

Emission Standards for New-Nonroad Spark-[gnition Engines at or Below 19 Kilowatts:

. Response to Comments on the NPRM 5127/95-53­

It has been the Agency's practice to require the use ofobserved torque in the calculation of break-specific emissions in several past engine emission regulations, see for example §86.340­ 79(c)(3)(ii), §86.341-79(d)(7), §89.407-96(c)(8). At this time the Agency is not considering dropping this practice.



### 5.1 7 Engine stabilization - thermal stability requirement
5.17.1. Summary ofthe Proposal The proposal required manufacturers to run the test engine ateachmode speed and torque set point for a sufficient amount oftime to achieve thermal stability, with a minimumrequirement that engine cylinder headtemperature remain constant for three minutes at 

### ± 5° Celsius.


### 5.17.2. Summary ofthe Comments Onan Corporation requestedthat manufacturers be allowed to make their own determination ofhow long an engine needs to run before 

### it is stabilized. PPEMA statedthat a three minute stabilization time may be too long a time period for the wide open throttle mode for some Class ill, IV, and V engines without possible engine damage. PPEMA requested that manufacturers be allowedto make their own determination ofstabilization time. Kubotarequested that oil temperature measured in the oil panbe an alternative to cylinder headtemperature.


### 5.17.3. EPA's Response to the Comments The final rule has been modified from the proposal to take into consideration the comments
on this topic. The Agency agrees that more than one criterion canbe used to determine thermal stability for the purposes ofemission measurement, including, but not limited to, cylinder head temperature and oil temperature. The tester now has two options, one is to determine and document the appropriate criterion for thermal stability for eachengine family. Ifthe manufacturer does not want to make this determination, they can use the requirement thatcylinderhead temperature must remain within a lOoC bandwidth for three minutes.



### 5.18 Data Sampling Period and Frequency
5.1B.l. Summary of the Proposal The proposal requires manufacturers to record the emissions and engine data for at least four minutes once the engine is stabilized, and to sample the data at a minimum rate of 1Hz.


### 5.1B.2. Summary ofthe Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-54­



### The Agency received essentially the same comment from Onan Corporation, Echo Incorporated, Kubota, and PPEMA. In every case the comments did not mention the 1Hz sampling rate as aproblem, buteach commenterrequested the Agency decrease the sampling time. Manufacturers requested a two minute sampling time fortwo reasons, to harmonize with the CARB Utility, Lawn and Garden engine regulation, and because two minutes should be a sufficient sampling time because thermal stability has already been achieved.
5.18.3. EPA'sResponse to the Comments The Agency agrees with the comments received. An examination ofseveral sets ofEPA small engine test data showed that once thermal stability is achieved, doubling the sampling period from two to four minutes resulted in less than aone percentchange in the average values ofengine speed, torque, total hydrocarbon concentration, and oxides ofnitrogen concentration. Based on this information and the comments received from manufacturers the Agency has changed the fmal rule to require aminimum sampling period oftwo minutes for each mode.



### 5.19 Averaging of speed and torque data for power calculation
5.19.1. Summary of the Proposal The proposal required that a manufacturercalculate the powerfor each mode by averaging the individually calculatedpower values during the mode.
5.19.2. Summary of the Comments Onan Corporation suggested that a manufacturerbe allowed to calculate the average power for each mode from the average speed and the average torque.
5.19.3. EPA's Response to the Comments The correct formula for calculating the average powerduring amode is



### l' .0 21'C x speedj x tarquftj 

## 1=1. 60,000 Average Modal 

### Power •**.tf.-;;;::"'-~---ll-----""'-**



### Onan's suggestion would change the formula to be

Emission Standards for New-Nonroad Spark·lgnition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127195-55­

Average Modal Power. 2x x average speed. x average torque 60,000



### These two equations are not identical and would not produce the same result. Forthis reason, the Agency**willl~ave** 

### the calculation as proposed; averagepowermust be calculated from the average ofeachindividually calculatedpowervalue.



### 5.20 Emission Bench Calibration Information
5.20.1. Summary of the Proposal The proposal contained a paragraph underthe 

### data logging section stating "Forpurposes of this section, calibration dataincludes calibration curves, linearity curves, span-gas responses, and zero-gas responses'."


### 5.20.2. Summary ofthe Comments The Onan Corporation corrunented thatthis paragraphrequired 

### that infonnationbe logged during the test that is'typically not recorded as part ofthe actual test 

### datalogging information. Onan suggested that this paragraph does notbelong inthis section.


### 5.20.3. EPA's Response to the Comments The Agency agrees with Onan's comment. This paragraph does not deal with the subject ofthis section, which is 

### data logging during the test. This paragraph has been removed from the final rule.



### 5.21 Automatic Data Collection Of Continuous Analyzer Response
5.21.1. Summary of the Proposal The proposal required manufacturers to maintain for long term storage the average value of the continuous analyzer response. 

### 5.21.2. Summary of the Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-56­

The Onan Corporation requested that manufacturers be allowed to maintain for long term storage the individual data points from a continuous analyzer which couldbe averaged as necessary. 

### 5.21.3. EPA's Response to the Comments The Agency agrees with the comment. Ifa manufacturer wanted to maintain individual data points from a continuous analyzer response instead ofstoring the average value this would not affect the Agency's ability to request the average response value. The final rule has been modified to allow for this option.



### 5.22 Engine Cooling Fan For Air Blowers/Pumps
5.22.1. Summary of the Proposal The proposal required that all enginesbe tested with the cooling fan installed.


### 5.22.2. Sum:nary ofthe Comments PPEMA and Echo Inc. commented that for certain engine types, suct) as engines used in air blowers, the engine's cooling fan absorbs 90-98 percentofthe engine's power, so the engine would not be capable ofperforming the engine testcycle with the cooling fan installed. Both comments stated that the Agency must give some consideration for these types ofengines.


### 5.22.3. EPA's Response to the Comments The Agency agrees that special provisions must be made for these types ofengines. The engine test cycle wouldnotbeperformed ifthe engine cooling fan absorbs such a large portion of the engine's power. The final rule hasbeen altered to allow for the removal ofthe original cooling fan and the addition ofan external cooling fan for engines whose cooling fan serves a dual purpose.


### 5.23. Analytical Gases - Pure Gases
5.23.1. Summary of the Proposal

. Theproposedrule requires that manufacturers use "pure" gases, defined by specific tolerances stated in the proposal, for use as zero gases, calibration and span gas diluents, andFID fuel.


### 5.23.2. Summary ofthe Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-57­

PPEMA commented that pure gases are not necessary for raw gas sampling ifthe fuel flow method is used.


### 5.23.3. EPA's Response to the Comments The Agency disagrees with PPEMAregarding this item. Regardless ofwhich testing method a manufactureruses, raw gas orconstant volume sampling, manufacturers must use pure gases for the zeroing of analyzers, the Fill fuel, and the diluent for gas dividers. The final rule has
no changes in it from the proposal regarding this topic.


### 5.24. Analytical Gases - Diluent for Hc-Fid Zero, Span and Calibration Gases
5.24.1. Summary of the Proposal The proposal had language under the calibration and span gas section listing propane/nitrogen mixture as well as a propane/zero air mixture, but the language did not have an explanation ofwhen it would be appropriate to use the two different mixtures as Fill span and calibration gases. 

### 5.24.2. Summary of the Comments PPEMA stated that purified nitrogen shouldbe the zero gas and the diluent for the HC-Fill analyzer span and calibration gases to avoid potentially explosive mixtures ofvery high propane concentrations with synthetic air.


### 5.24.3. EPA's Response to the Comments It was the Agency's intentto allow the manufacturers to choose what zero gas and diluent to use for the HC-Fill analyzerin the proposal. Additional language has been added to the final rule to clarify this point, as well as to make manufacturers aware ofthe possible dangers ofmixing high propane concentrations with synthetic air.


### 5.25. Analyzer Calibration - Step Calibration Requirement
5.25.1. Summary of the Proposal The proposal requires manufacturers to calibrate each analyzeroneachrange usedby performing a multi-point step calibration procedure.


### 5.25.2. Summary ofthe Comments

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-58­

PPEMA commentedthat the step calibrations are unnecessary because analyzercalibrations
are perfonnedby the instrumentmanufacturer and should not be the responsibility ofthe engine manufacturer.


### 5.25.3. EPA's Response to the Comments The Agency disagrees with PPEMA's comment. The Agency has found that analyzer calibration curves are not static and do change overtime. The stability ofanalyzer calibration
curves varies between analyzermanufacturers as well as between the different types ofanalyzers (HC, CO, C02, NOx). Currently, the only method known to the Agency to be certain that analyzer calibrationcurves have not changed is toperfonnperiodic multi-step calibrations. The final rule has not been changed as a result ofthis comment.



### 5.26. Oxides of Nitrogen Measurement, Accuracy and Instrumentation
5.26.1. Summary of the Proposal The proposal requires thatengine manufacturers use a chemiluminescentoxides ofnitrogen (NOx) analyzer with a measurement accuracy oftwopercent.


### 5.26.2. Summary ofthe Comments PPEMAcommented that a twopercent accuracy requirement on NOx was unnecessarily stringent for two-stroke engines, because two-stroke engines emit NOx levels well below the standard. In addition, PPEMA asked the Agency whetherornot a UV-NDIRNOx analyzer would be acceptable for testing. 

### 5.)6.3. EPA's Response to the Comments The Agency does not believe the accuracy requirements ofthe test procedure should be dependent onhowclose to an emission standard a particular type ofengine is and the fmal rule was not alteredregarding that comment. In the past EPAhas had some experience with UV-NDIRNOx analyzers and has not found them to be as accurate as the chemiluminescence type. However, the proposed regulations do allow for the use ofother analyzers, as long as the manufacturer can show the analyzer shows equivalent results tothe required type, and this language remains in the fmal rule. Section 9O.313(b) ofthe fmal rule states that "Othertypes ofanalyzers and equipment may be used if shown to yield equivalentresults and ifapproved in advance by the Administrator."

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### 5.27. Testing Mode Intervals
5.27.1. Summary of the Proposal The proposal requires that a delay ofmore than one hourbetween the end ofone mode and the start ofa second mode would void a test.


### 5.27.2. Summary ofthe Comments PPEMA commented that EPA should not limit the duration between one test mode and the next.


### 5.27.3. EPA's Response to the Comments The Agency believes that the certification test should be a single test performed on a single day with as few interruptions as possible. The Agency is concerned that allowing manufacturers to
run the different test modes on different days orwith large gaps oftime between modes would pose questions ofrepeatability and possible gaming by the engine manufacturer. The test cycle which most PPEMA. members will be responsible for performing is Cycle C, the two-mode cycle. Once the first mode is completed, the amount oftime necessary to complete the second mode, including stabilization and sampling time, should not be more than 10 or 15 minutes. The Agency does notbelieve this will impose any significant burden on the engine manufacturers and the final rule will notbe altered because ofthis comment.


### 5.28. Mixing Chamber Requirements - Helmholtz Frequency Requirement
5.28.1. Summary of the Proposal The proposal's description ofthe optional mixing chamber was taken from the SAE 11088 recommendedprocedure.


### 5.28.2. Summary ofthe Comments PPEMA requested that an additional requirementbe added to the language regarding the mixing chamber, specifically, that the Helmholtzfrequency ofthe mixing chambernot exceed 1110 ofthe engine's firing frequency.


### 5.28.3. EPA's Response to the Comments The Agency used the language from the SAE 11088 recommendedprocedure to describe the optional mixing chamber. Without further explanation ofwhy the description ofthe mixing chamber should be different from the SAEdescription, EPA will not alterthe proposed language.

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IfPPEMAcan demonstrate that a technical errorhas been made, the Agency wouldconsider making a Technical Amendmentto the final rule at that time.



### 5.29. Acceptance of the Micro-Dilution Tunnel Testing Method
5.29.1. Summary o/theProposal Theproposal described three acceptable emission testing methods, raw gas sampling with airand fuel flow measurement, raw gas sampling with fuel flow measurement, and constant volume sampling.


### 5.29.2. Summary o/the Comments PPEMArequestedthat the Micro-Dilution Tunnel (MDT) testing method developedby one ofits members be included as an acceptable method ofemission sampling.


### 5.29.3. EPA's Response to the Comments Due to time,and resource constraints. the Agency has not been able to perform a complete analysis ofthe MDT method. The final rule has not been altered to include the MDT method. However. as proposed. the final rule does allow for manufacturers to propose alternative test methods which couldbe deemed acceptable by the Administrator.



### 5.30. Air Flow Measurement for Two-Stroke Engines
5.30.1. Summary o/theProposal The proposal described three acceptable emission testing methods: raw gas sampling with air and fuel flow measurement, raw gas sampling with fuel flow measurement, and constant volume sampling (CVS).


### 5.30.2. Summary o/the Comments PPEMA commented that air flow measurement should notbe required for two-stroke engines.


### 5.30.3. EPA's Response to the Comments The Agency does not specify which ofthe three sampling methods a manufacturer must use to comply with the rule. No manufactureris forced to use the raw gas method (RGM) with air and fuel flow measurement; boththe RGM with only fuel flow orthe CVS method are acceptable. 

### In

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addition, as in the proposal, the final rule allows manufacturers to propose alternative test methods which could be deemed acceptable by the Administrator.



### 5.31 Catalyst Durability Cycle: Change to Test Requirements
5.31.1. Summary of the Proposal The notice proposes the evaluation ofcatalyst durability bymeans ofthennal stress testing. Suchtesting involves the use ofheated air for preconditioning and aging catalysts andthe use of synthetic exhaust gas for detennining catalyst conversion efficiency.


### 5.31.2 Summary ofthe Comments The comments that were submitted by the Manufacturers ofEmission Control Association (MECA) proposed the adoption ofan optional hydrothennal stress test and recommended an increase in the concentration ofC02 in the synthetic exhaust gas.


### 5.31.3 EPA's Response to the Comments The MECA comments noted that the proposed hydrothennal stress test, which involves exposure in a 90percent nitrogen/topercent steamenvironment at a temperature in excess of 850°C, has been adopted bythe industry for evaluating catalyst washcoat durability. This procedure is basedon infonnation which shows that wateris the component ofactual exhaust gas which can cause an undesirable reduction in the surface areaofa washcoat that does not have adequate stability. In response to the MECAproposal, the use ofa 90percent nitrogen/to percent water vaporenvironment has been adopted as an alternative to an airenvironment during catalyst preconditioning and aging. The resultant availability ofalternative procedures, thennal stress testing with air and hydrothennal stress testing with the nitrogen/water mixture, will allow the optional use ofthe catalyst durability evaluation procedure that is most appropriate for specific engine applications. Priorto the publication ofthe NPRM, MECAhad recommended the use ofa synthetic exhaust mixture which contains 3.8 volume percent C02. The recommendationin the MECA comments for an increase in this value to 9 percent or 10percent is based on information which shows that the concentration ofC02 in the exhaust gases emitted by small nonroadengine ranges from 9 percent to 12 percent for 4-stoke engines and 2 percent to 10 percent for 2-stoke engines. In response tothe MECA recommendation, the C02concentration has been raised from 3.8

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percentto 9 percentto make the synthetic exhaust gas mixture more representative ofactual exhaust gas mixtures that are emittedby the kinds ofengines that are coveredbythe Part90regulations.



### 5.32 Exhaust Gas Composition for Testing of Three-Way Catalysts
5.32.1 Summary of the Proposal The composition ofthe synthetic exhaust gas mixture thatis specified in the proposal is comparable to compositions ofsynthetic exhaustgas mixtures currently used by catalyst manufacturers for testing related to the kinds ofengines covered bythe proposal.


### 5.32.2 Summary ofComments MECAcommentedthat ifthe catalyst manufacturer specifies that a catalystis designed for three-way control, the manufacturer should have the options ofusing HC+NOx combined conversion as a basis for detennining durability andofusing a rich synthetic exhaustevaluation gas with either4650ppmHC or 1.2percentCOratherthan 4000ppm Heand 1percentCO which are parameters for a stoichiometric mixture.


### 5.32.3 EPA'SResponse to the Comments EPA allows the use ofHC+NOx combinedconversion as a basis for detennining durability where the standard is also expressed as HC+NOx (forClasses I and II only). NOx conversion requires that a slightly rich exhaustmixture be present. We expectengines designed to meet Phase 1emission standards to operate on the rich side ofthe stoichiometric mixture. Therefore, using a stoichiometric gas mixture would notbe representative ofthe exhaust gas the three way catalyst will see in actual use. Therefore, EPAhas changed the final rule to allow manufacturers to utilize 4650 ppm HC or 1.2 percentCO.



### 5.33 Deterioration Limits
5.33.1 Summary of the Proposal The agency proposed a fixed catalystefficiency loss limit of20 percent for HC, CO and NOx. This was proposedbased on EPA's on-highway experience and the absence ofinformation at the timeregarding the conversion efficiencies that will be used with small engines.


### 5.33.2 Summary ofComments MECA submitted the following comments:

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1. Require only demonstration ofhydrocarbon conversion durability. 2. 

### Ifdemonstrations ofCO andNOx conversion durability are also required, the following options are recommended:
a. The catalyst manufacturer can designate catalysts astwo-way (He and COcontrol) or three-way (He, CO and NOx control). b. A two-way designation would eliminate the need for the demonstration ofNOx conversion durability. 3 . Failure to comply with the COconversion deterioration limit would not preclude the certification ofa two-way catalystthatis intended for use onengines with low engine-out CO emissions.


### 5.33.3 EPA'S Response to the Comments The Agency has decided that catalysts should not be accountable for pollutants which they
were not designed to reduce/oxidize. Therefore, the engine manufacturer must specify the pollutants that the catalyst will be converting and submitdataononly that pollutant. Forcatalysts thatconvertCOon an already low COemittingengine (ie: COlevels are below the standards-enough such that ifthe catalystis removed ordeteriorates to 0% efficiency on conversion ofCO, then the engine will still emit COemissions below the CO standards), the catalystmanufacturer ofthe two waycatalyst will nothave to meetthe COconversion deterioration limit.


### 5.34 Purpose of Catalyst Durability Cycle
5.34.1 Summary of the Proposal While the conversion efficiency for catalysts for small engines are expectedto be less than those for on-highway, EPAis concerned that durable catalysts are utilized on the small engines. The purpose ofthe durability cycle for catalysts is to "ensure that durable catalysts are used on small engines while avoiding excessive requirements thatcoulddiscourage the development of very promising catalysttechnology."


### 5.34.2 Summary ofComments Three sets ofcomments were received onthis proposal. EMAlOPEI stated that the requirementfor durability demonstration by the catalyst manufacturer should notbe included in the final rule because ofdisharmonization with

## eARB and federal regs and because EPA's costestimates regardingthe use ofcatalysts did not take into account the additional costs the industry wouldincur ifsuchcatalyst mustfirst be certifiedfor durability

.

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EMNOPEI stated that the issue ofwhether the engine orcatalyst manufacturer shouldbe responsible for the durability demonstration should be addressed through the Phase II Regulatory Negotiation. The comments that were submittedby the Portable Power EquipmentManufacturers Association (PPEMA) expressed uncertainty about whether the proposed durability testing oflow efficiency catalysts would be sufficientto ensure emissions compliance. PPEMA also stated that EPA should specify thatcatalysts manufacturers will be responsible for any noncompliance with applicable emissions standards due to design or manufacturing defects in catalysts. STAPPA stated that such a requirement is merely a screening tool designed to identify those profoundly inadequate catalysts and that itdoes not necessarily constitute a thorough demonstration ofexpected catalystefficiency durability. Nordoes such a requirementprovide information related to the in-use emissions ofthe overall engine-aftertreatment system.



### 5.34.3 Response to the Comments The catalyst"durability requirement in this rule is compatible with CARR since California does not preclude use ofcatalysts demonstrated by the catalyst manufacturer on the proposed durability demonstration procedure. 

### In addition. CARR requires a two year warranty on all emission related components and the durability procedure provides a mechanismfor engine manufacturers to assure they are receiving components which will be in compliance. EPA desires also to assure that a catalysts used on a small engine will be durable for a significantportion ofthe engine's useful life and notjustfor the dynamometer certification test. EPA wouldconsiderincluding the cost estimates for catalystcertification ifit was thought to be a significantcost overall to the use ofcatalysts. Catalyst manufacturers have recognized the importance ofsuch a requirement to ensure that all catalysts used in the marketplace are ofat least a baseline qUality. This provides a level playing field in the marketplace. The demonstration procedure focuses only on thermal aging thus allowing lower costoven aging andless complexity
over an engine aging procedure. However, no cost information has been given to EPAby engine and catalyst manufacturers. EPAbelieves the costs ofcatalyst certification for small engines will be small. The issue ofwhether the engine orcatalyst manufacturer should be responsible for the durability demonstration will be addressed in application to Phase II standards during the Phase II Regulatory Negotiation. The amount ofreduction expected by the Phase II small engine catalysts will likely be significantly more than that expected for Phase I and greaterdefinition ofwhat would constitute adequate durability will be warranted.

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PPEMA's uncertainty regarding the adequacy ofthe proposed catalyst durability evaluation procedure for ensuring emissions compliance is based primarily on the expectation that Phase I catalysts will have low efficiencies. PPEMA has provided no data or engineeringrationale as to why low efficiency catalysts would be more poorly represented on the proposed durability procedures than othercatalysts. EPA's technicaljudgment is that both low and high efficiency catalysts that survive the proposed durability procedures and meet certification test requirements will perfOl1D:-; as expected for a reasonable period in-use. The PPEMA commentemphasizes the need for clarification ofthe purpose ofthe required catalyst durability evaluation. The purpose ofsuch testing is to identify catalysts which are so inadequately designed and fabricated that they fail to meet the minimum standards that are recognized within the industry. The durability evaluation procedure is not intended to guarantee compliance with the applicable emission standards for the full useful life ofthe affected engines. Such compliance is dependent on a number ofvariables, some ofwhich, such as the engine-out emissions, are not directly related tothe condition ofthe catalyst. Such variables will be more" effectively evaluated by considering the overall emission control system durability. This will be at issue in the Phase II regulations. Finally, PPEMA commentedthat EPA should specify that catalyst manufacturers will be responsible for any noncompliance with applicable emissions standards due to design or manufacturing defects in catalysts. EPA holds the engine manufacturer responsible for the final engine system it tests. Itis not the Agency's intent, nor its responsibility, to determine the actual
cause ofnoncompliance shouldit occur. That responsibility remains with the engine manufacturer
even when it chooses to use a catalytic converter as part ofits emission control system.



### 5.35 Worst Case Emitter
5.35.1 Summary of the Proposal EPAproposed to use the criteriaofhighest weighted brake-specific fuel consumption (BSFC) overthe appropriate engine test cycle to determine that engine configuration within an engine family which will be selected as the certification test engine. EPAbelieves that an engine configuration with high BSFC will generally emit higher levels ofhydrocarbons and carbon monoxide than a second configuration in the same engine family which has a lowerBSFC. EPA solicited comments on the appropriateness ofweightedBSFC as the criteriato be used for selecting the worst case emitter. EPAconsidered leavingthe selection ofthe worst caseemitterup to the engine manufacturer with the guideline that the engine manufacturer must test thatengine configuration

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within an engine family which is most likely to exceed any emission standard. EPA solicited comment on the appropriateness ofthis approach for selection the worst case emitter.


### 5.35.2 Summary ofthe Comments Onanrecommended that the methodfor selecting the specific engine in a family that will be certified should be that which is used in CARB's Tier I rule. Onan questioned the ability to establish a relationship between BSFC and weighted exhaustemissions by the EPA. Onan stated thatEPA shouldleave the selection ofthe worstcase emitter up to the engine manufacturer. This wouldessentially be the same as the CARB Tier I rule which would promote harmonization as well as provide representative emission certification data.


### 5.35.3 EPA'S Response to the Comments EPA has decided that the manufacturer should make the selection based onits technical judgmentorevaluation ofthe emission performance ofthe vehicles remaining in the engine family. EPAdoes not expect manufacturers to conduct an extensive programto determine worst-case engines, nordoes EPA intend to challenge manufacturers' selections unless EPA suspects that a manufacturer is purposefully subverting the intent ofthese regulations. Ifsuspected, then the engine manufacturer will be requested to providejustification for the choiceofworstcase emitterto the Administrator. TheAdministrator will then have the opportunity to review the documents and require additional documentation orchanges in the choice ofthe engine chosen.



### SEC"nON 6: SELECTIVE ENFORCEMENT AUDITING



### 6.1 Attached Equipment. During An SEA
6.1.1 Summary of the Proposal As described in the proposal, EPA typically would select SEAengines from a point offinal engine assembly, from a storage or shipping facility, or in the case ofimportedengines, ata port ofentry. Mostoften, this selection point would

### be at the end ofthe engine assembly line, where no further quality control procedures happen and where no additional parts would be installed on the engines. SEAengines could not receive any additional inspections orquality control otherthan that ofnormal production engines and pre-test safety checks. Engines wouldbe tested inthe same

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order as they were selected. In the NPRM. EPA requested comment on the feasibility ofselecting equipment, then removing the engine for audit testing.


### 6.1.2 Summary ofComments PPEMA stated that some handheld products, such as string trimmers, blowers and pumps, incorporate a built-in load. 1S6 Forpurposes ofminimizing audit costs, PPEMA believes that manufacturers should have the option ofconductingemissions testing on the equipment itself, using rated power and rated speed as specified in the certification application, rather than removing the engine and conducting dynamometer testing. In response to EPA's request for comments, Kohler expressed objections to the possibility ofincluding equipment as part ofthe audit process, stating that this would be an unnecessary

.burden on engine and equipment manufacturers.IS7 Kohlerexplainedthat it manufacturers engines which are sold to equipment manufacturers through a distribution system, so it does not have ready
access to production equipment. Kohler objected to EPA's proposed program, saying that it would either require a customerto remove engines orto ship the equipmentto Kohler to have the engine removed, test and reinstalled, a program which would be time consuming, costly, and without justification.


### 6.1.3 EPA's Response to the Comments Because SEAtesting is an enforcement tool used to verify that production engines comply with emissions standards and that production engines are assembled in all material respects as described in the manufacturers application for certification, EPA will not grantbroadpermission for manufacturers to use such alternative test methods. EPA is notprepared to permit SEA emission testing ofequipment. Equipment may contribute to the loadexperiencedby the engine which could affect emissions. In addition, this rule specifically regulates engines, not equipment. Manufacturers' voluntary assembly line testing programs (ALT) may utilize alternative test methods to provide whateverlevel ofconfidence the manufacturer so desires,and manufacturers have the opportunity to propose alternative test programs for phase two regulations for small SI engines. Manufacturers may individually propose alternative test methods and provide datato demonstrate that the alternative test method generates emission levels representative ofthe prescribed test procedures.


### 6.2 Additional Parts Necessary For An SEA
6.2.1 Summary of the Proposal The Agency's proposedrule states that SEAengines would typically be selected from a point offinal engine assembly orfrom a storage or shipping facility. Most often, this selection

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-68­
point would be at the end ofthe engine assembly line, where no further quality control procedures happen orparts would be installed on the engines.


### 6.2.2 Summary ofthe Comments ONAN and EMA explained that many small engine manufacturers ship theirengines without mufflers and/or air cleaners.IS8 The SEAtest procedure would have to allow these and other OEM/customer supplied parts to be added to the engine prior to SEA testing.



### 6.2.3 EPA's Response to the Comments EPA has experienced similar situations conducting SEAs ofon-highway engine manufacturers. Certain manufacturers ship engines without "dress parts" to their facilities in distant locations. During an SEA, EPA allows time for manufacturers to make provisions to have the necessary parts shipped from other facilities. This liberty will be extended to manufacturers covered under this regulation. It may be necessary for EPA to oversee the selection ofadditional parts, depending on the part.


### 6.3 Annual Limit Of SEAs
6.3.1 Summary of the Proposal EPAproposed an annuallirnit oftwo SEAs for each manufacturer with projected annual production ofless than 100,000 engines. For manufacturers with annual production of 100,000 or
more engines the proposed annual limit wouldbe the greater ofeithertwo orthe number determined by dividing the numberofengine families certified in that model yearby five, and rounding to the nearest whole number.


### 6.3.2 Summary ofthe Comments Onan stated that the number ofSEAs allowed peryear would be burdensome. 1S9 Due to the complexity ofits productline, Onan projects it would be forced to run three or more SEAs in a given model year. Although Onan would prefer dividing the number offamilies by eight rather than five, it feels that limiting the number ofSEAs to one ortwo peryear is best, especially given the fact that the EPAcould run as many SEAs as it deemed necessary ifEPAdecided that noncompliance was occurring. Onan commented that the Administrator should not have the authority to exceed the annuallirnit of SEAs without goodcause. NRDC opposed EPA's proposal to set an annual limit on the number ofSEAs per manufacturer and emphasized that in the early stages ofthe program, special enforcementefforts

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will be needed to ensure compliance by small engine manufacturers that may be confronting an EPA airemissions regulation for the first time. 100 NRDC believes that a self-imposed limit offour audits annually does notfurther the objectives ofthe SEA program - to ensure that manufacturers take steps necessary to ensure that all engines rolling offthe assembly line are built to the same standards as the certification engine. In its comments, EMA statedthat EPA should revise its basis for determining the number ofSEAs each manufacturercould receive annually. 161 EMA believes that the proposed annual limits would impose an undue burden on all small SIengine manufacturers and therefore encourages EPA to limit to no more than two the number ofSEAseach manufacturercouldreceive annually in the absence ofexceptional circumstances.


### 6.3.3 EPA's Response to the Comments EPAbelieves that itis reasonable to assure manufacturers thatthey will notbe overburdened by SEAsby providing annual limits. However, with respect to manufacturers with projected annual sales ofover 100,000 engines and a large variety ofengine families, each SEA
canonly check a small portion ofthe manufacturers' production. EPA believes that relating the annual limit to the number ofengine families as proposed will allow EPAto check a reasonable portion ofa manufacturer's production. With respect to manufacturers with projected annual sales ofless than 100,000engines, an annual limit ofone would not allow EPAto have the flexibility to return to a manufacturer that had passed an SEA early in the model year and subsequently implemented changes in its production process that could increase engine emissions. Therefore, EPA believes that the proposed annual limit systemis appropriate for Phase I regulations for small SI engines.


### 6.4 Number 01 SEAs Per Day
6.4.1 Summary a/theProposal EPAproposed thatengine manufacturers with projected United States annual sales of 7,500 orgreatermustcomplete a minimum oftwo engine tests perday during an SEA. Engine manufacturers with projected United States annual sales ofless than 7,500 would be required to complete a minimum ofone enginetestper day during an SEA.


### 6.4.2 Summary a/the Comments Gnanbelieves thatthe requirementthat manufacturers complete two tests per day is
onerous. 162 Gnan explained that ifthe engine selected for audit has a service accumulation period ofmore than a few hours and the manufacturer does the service accumulation and SEA test on the
same dynamometer (not an unusual practice; it saves set up and removal time), then only a single

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SEA test couldbeperfonnedperday unless more than onetest cell/dynamometer was used. Making two test cells available during an SEAcouldbe a tremendous burden on manufacturers who may only have a few cells that are capable ofmeasuring emissions. Onan suggested that the EPA waive any requirement for a minimum number ofSEA tests perday and instead require that the manufacturer make a good faith effortto complete as many tests as possible perday. Atworst, Onan believes, a minimum ofone test perday should be required ofall manufacturers.


### 6.4.3 EPA IS 

### Response to the Comments EPA may permit fewer tests perday ifa manufacturer is making a good faith effort to complete testing expeditiously. Because manufacturers have indicated a preference for selfauditing EPAexpects that manufacturers will have several testcells for new engine compliance testing, either for voluntary testing orfor ARB compliance testing. Consequently, EPAexpects that test cells will be available for occasional SEA testing.



### 6.5 Sampling Plans
6.5.1 Summary o/theProposal The total number ofengines tested in an SEA would be dictated by the statistically acceptable pass/fail decision within the sampling plan applied, as described. EPA proposed a sequential sampling plan for small SI engine SEAs. These sampling plans were designed to meet a 40Acceptable QUality Limit (AQL) and to ensure low statistical risks ofincorrect pass/fail determinations. The maximumtheoretical percentage offailing engines for passing an SEA was proposedto be 40percent AQL for the small SI engine SEAprogram. 

### 6.5.2 Summary o/the Comments EMAbelieves that EPA should allow manufacturers to submit alternative sampling plans.l63 In its comments, EMArecommended that EPA make alternative sampling plans available for use at the manufacturer's discretion as optional methods for audit testing at any level ofengine family production volume. EMArequested that alternative samplingplans be structured so that manufacturers are required to run fewer tests, but face a somewhat increased risk offalse failure. EMAwould also like EPA to allow engine manufacturers to choose whether to acceptthe increased risk

-- weighed against the cost savings

-- from reduced sampling. According to EMA'scomments, the Californiaregulations allow manufacturers to propose and rely on alternative sampling plansprovidedthey demonstrate that the alternative procedure will provide an equivalent assurance ofcompliance. EMA suggests thatthis same approach shouldbe takenbyEPA in allowing manufacturers to conductreduced sampling with increasedrisk.

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### 6.5.3 EPA's Response to the Comments EPA has found that the sampling plans offered under the current on-highway program adequately balance manufacturerburden with both manufacturer and EPArisk. EPA has not had sufficient discussions with manufacturers and therefore is not prepared to offer an alternate sampling plan at this time. However, EPA may consider requests by manufacturers to terminate testing early during SEAs oflow production families when the audit results are significantly and consistently below each applicable standard, and selection ofadditional engines would be difficult
orcause a delay in shipment ofcustomer-orderedengines, orthe manufacturer's test facility does not have sufficient capacity to expeditiously conclude the SEA. 

### An alternate sampling plan may be offered under Phase 2.



### 6.6 SEA Self-Auditing
6.6.1 Summary of the Proposal The SEAprogramdescribed in the NPRM strives to encourage manufacturers to perform self-auditing and promptly remedy the emission noncompliance it discovers. As proposed, EPA would consider reducing the number ofaudits conducted by the Agency, minimizing audits of engine families which are unusually burdensome to audit, orboth options, ifthe manufacturer provided substantial datato demonstrate conformity ofactual production engines with the applicable emission standards.


### 6.6.2 Summary of the Comments EMA'scomments encouraged EPA to adopt a voluntary self-audit program in lieu ofSEA testing. 164 EMA expressed concern that nowhere in the proposed regulation itselfdid any language appear that would assure credit wouldbe given to manufacturers for self-audits. Internal audit programs conductedby manufacturers should be relied on by EPA as a legitimate substitute for the use of SEAs, according to EMA, and notjust as an alternative that may promptEPAto considerreducing or minimizing a manufacturer's annual SEA limit. Itis EMA's beliefthat the consequences offailure to pass an SEA audit are sufficient incentive for engine manufacturers to develop thorough and reliable internal audit procedures to
ensure that engines will be designed to pass a possible SEA audit. Under EMA's described voluntary self-audit program, manufacturers would be required to submittheir audit data to EPA. 

### IfEPA questioned the credibility orreliability ofa manufacturer's audit data orprocedures, EPA could focus on the particular questionable aspect ofthe

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manufacturer's self-audit program and impose SEAs where the dataprovided were insufficient or evidenced an uncorrected failure. EMA and Onan both argued that EPA should allow manufacturers to submit the data generated to meet their obligations to CARB under its quality-audit test procedures as an alternative to SEA testing. 165 As an option, EMA and Onan expressed interestin submitting ISO-9000 series registration datain lieu ofSEA testing. 166 Registration under 900I, 9002 would demonstrate that a manufacturerhas a quality system in place that would assure products are made as intended. Such registration is recognized worldwide as a quality indicator and shouldbe a reliable basis for reducing oreliminating SEAliability. In addition, EMA did not support EPA's proposal to conduct spotchecks ofmanufacturer self-audits as discussed in the NPRM, and ifEPA were to perform such spot checks, suchchecks. must be creditedto an engine manufacturer's annual SEAlimit. PPEMA's understanding from the proposal was that EPA may reduce the number ofSEAs to which a manufacturer may be subjectbased upon the manufacturer's self-audit system.167 PPEMArequested c:larification as to whetherengine manufacturers are obligated to conduct or report on self-audits. 

### 6.6,3 EPA's Response to the Comments EPA has discovered cases where a manufacturer submits assembly line testdatathat is in compliance with the applicable emission standards, however an SEA on the same configuration shows noncompliance. Sometimes this discrepancy is caused by manufacturers who optto truncate parts ofthe Federal Test Procedure to expedite the self-auditing process. Therefore it is necessary to have the SEA program in addition to self-auditing. Itis not a requirement ofthis rule for manufacturers to conduct assembly line test or submitthe test data, however, EPA strongly recommends a self-auditingprogram and may reduce the number ofSEAs to which a manufacturer maybe subject.



### 6.7 Audit from Engine Family or Configuration?
6.7.1 Summary of the Proposal EPA proposed that nonroad SEAsbeconductedby sampling engines from within an engine family.


### 6.7.2 Summary of the Comments

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EMA stated that EPA should select only a single engineconfiguration from an engine family for audit testing. 168 EMA and OPElobjected to EPA's plan to make an entire engine family subject to an audit by reserving the option to select all engine configurations within an engine family for an SEA. 169 Instead, they believe the final rule should provide that only a single engine configuration from an engine family may be selected for audit testing, as is currently done for on-highway engine auditing. Tofacilitate testing, EMA and OPElrecommended that EPA evaluate a single engine configuration in each compliance test, or at most a single cylinder number and arrangement.


### 6.7.3 EPA's Response to the Comments EPAbelieves that making an entire small engine family subject to an audit would lead manufacturers to use extra care when grouping engines in a family.



### 6.8 SEAs and Manufacturer Production Schedules
6.8.1 Summary of the Proposal Tominimize the burden on manufacturers, EPA'sproposal stated that the Agency would consider requests by manufacturers to exclude particularengines orengine configurations from a test sample. Justification for suchrequests couldbeto avoid a delay in shipment ofurgent customer-ordered engines orto minimize test cell set-up time by selecting engines ofsimilar physical configurations.


### 6.8.2 Summary ofthe Comments Onan offered the following additionaljustifications for excluding particularengines or configurations from a test sample: no such engines orconfigurations in stock orcommitted for customerdelivery before they are again scheduled for production. 170 Onan believes that the regulation shouldcontainexplicitlanguage making it clearthat a manufacturer would not be required to modify its production or delivery schedule in orderto accommodate SEA.


### 6.8.3 EPA's response to the Comments As with the on-highway program, EPA will do its best not to disrupt a manufacturer's production schedule while conducting an SEA. EPA, however, will not add specific language which states that a manufacturer does not have to modify its production to accommodate an SEA. EPA believes that it may be necessary, atcertaintimes, for a manufacturerto alter its production to

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accommodate an SEA. Ifthe regulation specifically stated that a manufacturer does not have to alter its production, then it wouldbe possible for a manufacturer to postpone an SEA indefinitely.



### 6.9 Port Selection for Imported Engine SEA Testing
6.9.1 Summary of the Proposal EPA proposed to include ports ofentry or storage locations in the United States as locations for EPA selection offoreign-produced small SI engines for SEAemissiontesting at laboratories in the United States. The location ofthese selections couldbe designatedby the manufacturer to minimize disruption and shipping costs.


### 6.9.2 Summary ofthe Comments Hondaobjected to EPA's intention to adopt the port-of-entry as the SEA selection point for foreign produced small SIengines,I71 and notedthat it had spoken to this issue previously with regard to automobiles. 

### In that correspondence, Honda maintained that such a methodwould result in a significant increase in the cost and administrativeburden on manufacturers. 

### In its comments
on this proposal, Hondacontinuedto maintain this position for reasons it explained in more detail under the following topics: 1. Availability ofEmissions Test Laboratory, 2. CostEstimate, 3. ListofPotential Port Problems, 4. Diagnosis and Repair, 5. Consequences ofa Testing Failure. EMA statedthatEPA should allow, but not mandate, portofentry selection offoreignproducedengines.In EMA explained thatEPA'sproposedport-of-entry selection for foreignproduced small SIengines for SEAemission testing at U.S. laboratories presents problems of considerable potentialexpense to engine manufacturers. Engines produced overseas may enterthe U.S. as loose engines, cratedwith otherengines, or already installed in equipment required to have certifiedengines. Those engines that arrive already installed in equipmentmustnotbe subject to removal by EPA for testing at ports ofentry. IfEPA wishes to test such engines, it must do so before they are installed in equipment. Any other method would expose engine andequipment manufacturers to unnecessary additional costs and delays. EMA also expressedconcernthat even testing so-called "loose engines" may create similar disruptions. Becauseengines are often cratedtogether in amounts of 10-20engines in a single shipping container, removing one engine from a multi-engine shippingcontainerfor testing would create substantial additional charges. EMAand OPEl recommended thatEPA not mandate but allow engine manufacturers the option to choose port-of-entry selection offoreign-produced engines for testing atportfacilities. 173


### 6.9.3 EPA's response to the Comments

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Port selection would result in less expensive audits for EPA, and a more even distribution ofaudits among non-domestic and domestic vehicles and engines each year. 

### It would enable EPA to respond more quickly to reports ofnonconformity and, since the selection and testing would take place in the U.S., audits would not be affected by outside interference and would not require the prolonged absence ofEPA personnel necessary for overseas audits. EPA's quick response to
a report ofnonconformity benefits manufacturers in the long termbecause ifan SEA failure occurs, the manufacturer would have introduced less engines into commerce and therefore will be required to recall fewer engines. As with the on-highway SEA program, EPA will consider a manufacturer's concerns about shipping disruptions and the removal ofsuperfluous equipment before engine testing. EPA will 

### try to minimize disruptions while upholding the integrity ofthe SEAprogram. 

### In addition, manufacturers could designate selection location in orderto minimize disruption and shipping costs.



### 6.10 In-Use Testing For Phase 2 Versus Sea Auditing
6.10.1 Summary of the Proposal In the NPRM, EPA acknowledged its responsibility to achieve enforceable reductions of in-use emissions and plans to develop such measures in its long-term Phase 2 program.


### 6.10.2 Summary of the Comments Onan stated that "since no in-use enforcement program is being proposed for small SI engines, SEAprovides the only opportunity for EPAto determine the compliance ofproduction engines." 174 Onan wondered what this would mean ifin-use enforcement is used in Phase 2. Would EPA support the discontinuation ofthe SEA requirement orwould the Agency demonstrate why the two are not redundant, but are actually both necessary for enforcement?


### 6.10.3 EPA IS 

### Response to the Comments EPA believes that SEA and in-use are different and separate programs both ofwhich are necessary for the most effective enforcement program. SEA is a new engine compliance program which helps identify and encourages manufacturers to identify andcorrect noncomplying and marginally complying engines priorto their introduction into commerce. In-use enforcement helps to identify noncomplying engines in-use and provides incentive to manufacturers to build more durable engines. EPA will further address this issue in the context ofdeveloping the Phase 2 rule.



### 6.11 ,Designating Official Data

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-76­



### 6.11.1 Summary of the Proposal Wheneverthe Administratorconducts a test on a test engine orthe Administrator and manufacturereachconduct a test on the same test engine, the results ofthe Administrator's test will comprise the official data for that engine. 

### 6.11.2 Summary ofthe Comments Onan expressed confusion about the wording "designating official data," and found the wording ofthis section to be vague and ambiguous or, at the very least, confusing.175


### 6.11.3 EPA IS 

### Response to the Comments This statement means that the Administrator has the option to test an SEAengine at the Administrator's facility. The results ofthe Administrator's test wouldcomprise the official data for the SEA, evenifthe manufacturerconductedits own test on the same engines. Generally, SEAs
are conducted at the manufacturer's facility withEPA monitoring, so this provision is rarely applicable.



### 6.12 EPA May Specify SEA Governor Set Speeds


### 6.12.1 Summary of the Proposal Small enginesequipped with adjustable parameters must comply with all requirements of this subpart for any specification within the physically available range. 

### 6.12.2 Summary ofthe Comments Onanpointed out what it believedto be a section reference error. Onan also stated that the governor ofan engine should not beconsideredan adjustable parameterunderthe defmition of section 90.112, and therefore, the Administrator should not be allowedto specify the governor set speeds during an SEA.176


### 6.12.3 EPA's Response to the Comments The regulatory provision citedin this section should have been section 9O.112(c). Ifthe governorcannot beeasily adjustedby the customerthen the Administrator will notconsiderit an adjustable parameter. However, ifthe customer can adjustthe governor then the Administrator will considerit an adjustable parameter and can specify the set speeds during an SEA.



### 6. 1 3 Duration of the SEA

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-77­



### 6.13.1 Summary of the Proposal As described in the NPRM, the total number ofengines tested in an SEA would be dictated by the statistically acceptable pass/fail decision within the sampling plan applied. A test engine's pass or fail determination would be made by comparing final test results to the applicable federal emission standard.


### 6.13.2 Summary ofthe Comments PPEMArequested clarification ofthe potential duration ofany selective enforcement audit. 177


### 6.13.3 EPA's Response to the Comments 

### It is difficult to state the duration ofan SEA, since the duration ofan SEAis determined by many factors. Some ofthose factors include the number offailures, test lab availability, and the sampling plan used.


### 6.1 4 Dealers I.nvolved in SEAs/Recordkeeping
6.14.1 Summary of the Proposal As stated in the preamble, the manufacturer ofany new nonroad engine subject to any of the provisions ofthis subpart shall establish, maintain, and retain the following adequately organized and indexed records: (1) General records. and (2) individual records.


### 6.14.2 Summary ofthe Comments NAEDAexpressed concern that wording ofthe NPRM regulatory text indicatedthat dealers might be expectedto meet as-of-yet unspecified EPArecord keeping and information gathering requirements. 178


### 6.14.3 EPA's Response to 

### the Comments Under section 90.505(d) only manufacturers would be responsible for complying with the recordkeeping requirements.



### SECTION 7: IN-USE TESTING

Summary of the Proposal

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-78­

The Agency proposed a programto assure that manufacturers build engines that continue to emitbelow the emission standards they are certified to after suchengines are introduced into
commerce. EPA did not, however, propose an in-use emissions standqrd that engines would be required to meet overtheiruseful life. Section 213(d) authorizes EPA to enforce emission standards in-use; however EPA proposedto decide upon a useful life period and an in-use enforcement program in the Phase 2 regulations. ForPhase 1, EPAproposed only a program for requiring manufacturers to test engines in-use without a mandatory recall program to enforce such testing orenforce compliance with emissions standards in-use. Within this proposedprogram, a manufacturer would be encouraged to evaluate in-use emissions deterioration anddurability for purposes ofrefining its Phase I technology and by gathering the in-use testing databetterprepare themselves for an in-useprogram which may exist under the Phase 2 regulations. Specifically, the proposed program included the following: (a) A conditional certification concept in which the manufacturer wouldpropose an in-use test program at the time ofits new enginecertification by EPA, with subsequent manufacturer perfonnance ofthe in-use testing and reporting fulftlling the condition on the certificate; (b) Specific criteria wouldbe applied to the manu.facturer's proposed in-use test program, including what number ofengines would need testing, criteria for selectingtest engines, and requiredelements in collecting and testing in-use engines (including appropriate maintenance history, age ofengine, and specifications for the actual testing); and (c) 

### An annual in-use testprogramreporting requirement to insure adequate fulfillment ofthe above requirements.



### Summary ofthe Comments Comments on the in-use testing program were varied. Several commenters suggested that EPA wouldbe foregoing its legal obligation under the Clean Air Actifit did not promulgate, at minimum, the program proposed. Several commenters suggested revisions to the programto make it less burdensome on manufacturers. The remainderofcomments focused on the alleged inappropriateness ofany in-use programduring Phase I ofthe regulations and argued that conditional certificates were unjustified. Those commenters that supported EPA's proposed programincluded the Natural Resources Defense Council (NRDC) which argued that without any in-use compliance obligations, emission standards for new engines at the time ofcertification would not have much value inthe real world ofactual use. 179 NRDC also argued that both section 213 and section 207 ofthe Clean Air Act required an in-useprogramin Phase 1 and that such a program would be critical to the
success ofa more complete in-use program under Phase 2. 180 NRDC and STAPPNALAPCO supportedthe concept ofmanufacturer self-testing, as opposed tojointtesting by manufacturers or

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-79­

manufacturers with EPA, as a necessary step towards improving emission performance and gaining knowledge ofengine performance in a wide variety ofin-use conditions. 181 NRDC also supported EPA's proposal to make a certificate ofconformity conditional on manufacturer in-use testing. One commenterproposed an option whereby a collective gathering ofin-use engines could be conducted but individual manufacturers would still be responsible for self-testing. Several comments receivedeither suggested revisions to the proposedprogram or opposed the program and suggested revisions as a second option. Tecumseh proposed an alternative in-use programwhereby the manufacturer would conductthe testing in-house but the engines and equipment wouldremain the property ofthe engine manufacturer and thus avoid the burden of collecting equipment from consumers. 182 PPEMA proposed to allow manufacturers to use test camps to procure equipment or to performbench testing after accumulating engine use at an accelerated rate. 183 STAPP

### N ALAPCO suggested that two distinct types ofin-use testing be conductedby manufacturers, an up-front accelerated service bench testing and a testing ofengines in actual use to determine any correlation and to determine real life in-use performance. 184 Finally, several commenters either opposedthe in-use program as a first option orwere not in favor ofit at all. .Because the proposal for the Phase 2 regulations would soon follow the proposedeffective date ofPhase 1, these commenters felt that no in-use data from Phase 1could be used to determine the useful life ofengines for Phase 2 and therefore was not a reasonable justificationfor the collection ofin-use data. 185 Additionally, some commenters suggestedthat the Phase I regulations were intended to mirror California's tier I regulations and exclude immediate implementation ofany federal enforcementprograms. 

### In contrast to those commenters who argued that an in-use program was necessary to insure emission performance throughout useful life, commenters opposed to the programnoted that, absent a stated useful life, mandatory in-use testing is notjustified. 186 EMA argues that there is nojustification for conditioning certificates onthe completion ofin-use testing. 187 Several commenters were concernedthat an inuse testing requirement would impose unnecessary administrative andeconomic burdens on manufacturers. 188 Onecommenter suggested that a voluntary cooperative program between industry and EPA should be developed in place ofa mandatory program to develop meaningful data.


### EPA's Response to the Comments EPA has decided to allow a voluntary in-use testing program modeled on the testing program it proposed in the NPRM. EPA is not requiring an in-use testing program to be conducted by manufacturers. However, EPA anticipates that such testing anddata gathering will be beneficial for EPA's Phase 2 program. Should a manufacturer choose to run an in-use testing

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-80­

program, it may do so without EPA approval and set up its program as it chooses and may use the testing programdescribed in the NPRM as a model. EPA agrees with the commenters that noted that an in-use testing program is necessary to insure that new engines continue to meet emission standards for new engines attime of certification. Assuring that manufacturers build engines thatcontinue to meet emission standards beyond the certification and production stages is important. However, EPA is not establishing a useful life time period or an in-use standard that engines must comply with within this phase 1 rulemaking. Because no useful life time period or in-use standard has been established, EPA believes, as arguedby some commenters, that conditional certificates and mandatory in-use testing
are unjustified at this time. EPA agrees with the one commenterthat suggested that a voluntary in-use testing program be established. Thepurpose ofthe voluntary in-use compliance testing program allowed for by this rulemaking is not to establish a mandatory in-use recall requirement based on an engine's useful life and in-use standard. Instead ofa mandatory in-use testing recall requirement, EPA hopes that any voluntary in-use testing will allow manufacturers to take appropriate steps to avoid
orremedy in-use en:Ussion problems discovered and establish a database to utilize for phase 2 testing.Should a manufacturer chose to conduct a voluntary phase 1 in-use testing program, such program may pennitissues associated with a variety ofmaintenance and use conditions, testing or other issues to be identified andresolved priorto any phase 2 testing which may occur. Therefore, EPA has decidedto make manufacturer in-use testing voluntary and no annual reporting will be required. As noted in the preamble to today's final rule, EPA is suggesting that those manufacturers who voluntarily choose to conduct in-use testing use the model proposed by EPA within the NPRM as a model. Manufacturers may choose to conduct testing on accelerated-aged engines or make othermodifications as they find appropriate and may choose to follow the suggestions made by STAPP 

### AI ALAPCO in its comments. EPA will be available for any suggestions orguidance.



### SECTION 8: DEFECT REPORTING AND VOLUNTARY RECALL



### 8.1 Definition of Emissions-related Defect
8.1.1 Summary of the Proposal

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-81­

Therule defines anemission-related defect as a defect in design, materials, or workmanship in a device. system, or assembly described in the approved Application for Certification. Emission-related defects are to be determined by using procedures established by the manufacturerto determine safety orperformance-related defects.


### 8.1.2 Summary o/the Comments The Portable PowerEquipment Manufacturers Association (PPEMA) stated that the proposed definition ofan emission-related defect was unclear and suggested a revised definition which limitedthe reporting scope to those defects which result in an emissions nonconformity. PPEMArequested clarification on the meaning ofa performance defect. Kohler requested a listing ofemission-related components affected by this rule.


### 8.1.3 EPA's Response to the Comments Defectreporting regulations serve as an elementofthe Agency's in-use surveillance network. The purpose ofthe defectreporting regulations is to determine those defects which have
a high probability ofaffecting emissions. EPA does not want to overburden the manufacturers with reporting on defects which are not likely to affect emissions. Therefore, the definition ofan emissions-related defect will be expandedto include conditions which indicate a high probability of the defect affecting the emission performance ofan engine. The Agency believes that such conditions are met when the defect affects any parameter or specification enumerated in Appendix VIII of40CFR Part 85. This additional language should screen out those defects which are not likely to affect emissions. The definition provided in the proposedregulation has been expanded to read as follows: emissions-related defect means a defect in design, materials, orworkmanship in a device, system,
or assembly described in the approved Application for Certification which affects any applicable parameter or specification enumerated in 40 CFR Part 85, Appendix Vill. Appendix

## vm may eventually be revised to include a section dedicated to small nonroad spark-ignition engines. The components described in the approved Application for Certification will serve as a dynamic listing ofcomponents affected by this rule. Using an emission-component listing based
on the Application for Certification will provide the flexibility necessary to handle yearly changes in components that are due to technology advances for example. Itis for these reasons that the Agency does not compile a generic yet static listing ofemission components affected by this rule. While the manufacturers retain the determining function ofemissions-related defects, EPA must be given an opportunity to assess the emissions impact ofthese defects. As a result, PPEMA's proposal for submitting defect reports based solely onthe manufacturers' determination ofan emission exceedence cannotbe accepted.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-82­

The Agency is further attempting to minimize the burden placed on manufacturers by having manufacturers use existing methods and procedures for determining defects. Two examples ofexisting methods currently in place are those for tracking safety and performance defects. In the Agency's view a performance defect would be a defect which adversely affects engine performance to a level discernible to the owner, and as such would result in an owner complaintor service request. Othercomments received from the industry suggest that other types ofcustomer feedback as well as engineering performance tests may also be valuable sources of information that can be used to determine the presence ofdefective components.



### 8.2 The 25 Engine Trigger
8.2.1 Summary ojProposal Manufacturers are required to submit a defect report when an emissions-related defect is confIrmed to exist in 25 ormore engines ofa given engine family manufactured in the same certificate or model"year.


### 8.2.2 Summary ojComments Many manufacturers commented that the trigger of25 engines is too low for requiring a defect report. Manufacturers were concerned that the engines affected by the defect couldoften represent a percentage ofthe whole engine family that was too small to demonstrate the existence ofa true defect within the family. Manufacturers have suggested that the minimum trigger be raised to at least 75 engines, orthe greater of25 engines ortwo percent ofthe engine family's production. In addition, some manufacturers have requested the searching scope be reduced from engine families to engine models.


### 8.2.3 EPA Response to Comments Fromexperience with the on-highway program, most defects involve signifIcantly more than the 25 engines required to trigger a defect. If a defect is confIrmed in 25 engines, a signifIcant portion ofthe engine families involved are probably affected as well, except in the case of misbuilds which often affect only a small portion ofproduction. It is expected that an emissions-related defect would cut across engine models. By definition, engines categorized and certified as engine families have similar emissionperformance and durability characteristics. The same emissioncomponents will most likely be used within the various models that comprise an engine family. Furthermore, in certifying an engine family, the

.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-83­

manufacturer assumes responsibility for integrity ofthe family's emission components as well as its emission performance. The reporting scope ofthe current on-highway defect reporting regulations arebroader than this rule in that a defect report is required when 25 engines (or vehicles) for a given model year, not engine family, are affected. Basedon the Information Collection Request (lCR) document which supports this regulation and uses the broaderon-highway scope, it is estimated that each manufacturer ofnonroad engines, 19 kW and below, will file two defect reports per calendaryear. The Agency does notbelieve such a reporting rate is excessively burdensome tothe manufacturers. However, the Agency is willing to revisit the number 25 in the future, ifwarranted by information developed during practical application.



### 8.3 Appropriateness of Voluntary Recalls
8.3.1 Summary of the Proposal The proposedrule requires that manufacturers submit a voluntary emission recall report to the Agency when a manufacturer initiates a campaign to remedy an emissions-related defect. This proposed defect reporting rule defines a voluntary emission recall as a repair, adjustment, or modification program voluntarily initiated and conductedby a manufacturer to remedy any emission-related defect for which notification ofengine owners has been provided. The preamble refers to this portion ofthe rule by stating that EPA is proposing that individual manufacturers establish, when appropriate, voluntary emission recall programs. The preamble requested comments on how such a voluntary program mightbe effectively structured.



### 8.3.2 Summary ofComments Some manufacturers stated that no recall program, even voluntary, shouldbe included in the phase 1rule, while others commented that a voluntary program is acceptable as long as it does not serve as the basis for a mandatory program in the phase 2 requirements. The Agency was requested to 

### clarify when a voluntary recall program is considered appropriate.



### 8.3.3 EPA Response to Comments This rule does not require manufacturers to conduct voluntary emission recalls but only specifies the reporting requirements when a manufacijJ.rer chooses to do so.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-84­

The intent ofthe voluntary emission recall reporting (VERR) requirements is to have manufacturers send EPA specific information on repaircampaigns conducted voluntarily by manufacturers to remedy emissions related defects. Specifically, when a manufacturer determines that a defect exists, decides that the defect needs to be remedied, and chooses to contact the owners ofthe affected engines to notify them ofthe need for the remedy, then and only then are manufacturers required to submit a VERR under this rule. However, it is the practice ofonhighway manufacturers to send the Agency a VERR when a manufacturer decides for any reason to conduct a voluntary emission recall program. The Agency recognizes that under this rule the manufacturers may have the option of choosing otherremedial methods in lieu ofrecall campaigns and it is recognized that these methods may also be acceptable in the case ofvoluntary recalls conductedto remedy emission-related defects.The notice offinal rulemaking provides that when a manufacturer chooses to notify engine
owners ofa manufacturerinitiated campaign to remedy an emissions-relateddefect, that manufacturer must submit a Voluntary Emissions Recall Report.



### 8.4 Description of Method for Notifying Owners
8.4.1 Summary of the Proposal Manufacturers, when conducting a voluntary emissions recall as defined by the defect reporting requirements, mustprovide a description ofthe method by which the manufacturers will notify engine owners. 

### 8.4.2 Summary ofComments Manufacturers commented that this requirement shouldbe eliminated because, unlike the on-highway industry, the small spark-ignition segment ofthe nonroad industry does not have an
ownerregistration infrastructure. Furthermore, registration as a condition ofwarranty is not permitted underMagnuson-Moss Act. As a result, the manufacturers contend that it is extremely difficult to locate the endusers oftheir products.


### 8.4.3 EPA's Response to Comments This rule does not specify the method a manufacturer must use to notify owners, only that the manufacturer provide a description ofthe notification method chosenby the manufacturer. The Agency recognizes that, in general, manufacturers affectedby this rule do notpresently have in place an extensive ownerregistration infrastructure.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-85­

However, the Agency trusts that the manufacturers can devise creative, viable alternatives to the ownerregistration process for notifying owners affectedby manufacturer initiated recalls designedtoremedy emission-related defects. As examples, the manufacturers coulduse their dealernetworks as a resource in locating owners or manufacturers could advertise through the
mass media as 

### is currently done with safety related recalls. While the Agencyunderstands thatowner**regi~tration a~**  a condition ofwarranty is not permittedundertheMagnuson-Moss Act. manufacturers couldprovide incentives for owners to registertheirengines with the manufacturers. Streamlin1ng the current regislratiunprocesstGbe less burdensome to the engine owner may improve the percentageof0'WDel:s \lIbo return their registration cards. Finally, manufacturers, as mentionedearlier. may have the option ofchoosingother· remedial methods in lieu ofvoJuntary recaH carnpaigns COOOlict.edtorenllXly emi$;$lon-rdakd defects. Obviously, there would be no need for owner notification in these situations.



### 8.5 The Five.Year Reporting Period
8.5.1 Summary of the Proposal The proposal states that manufacturers are required to report emission-relateddefects affecting a class orcategory ofengines for five years from the end ofthe calendaryearin which the engines were manufactured.


### 8.5.2 Summary ofComments General concern was expressedthat the five yearreporting requirement was too long and shouldbe reduced to no longer than the twoyearwarranty period.


### 8.5.3 EPA's Response to Comments The Agency understands that afterthe required two yearwarranty period expires, manufacturers will no longerbe able torely on warranty claimdata as a method for detecting emission related defects. However, the Agency believes there are viable alternatives for detecting defects afterthe warranty period does expire, suchas tracking dataonpartreturns for safety andlor performance concerns. While these alternatives may notyield the volume or quality ofdata comparedto warranty claims, the data shouldbe sufficient in detecting egregious defects occurring outside ofthe engine's warranted life.

Furthermore comments received from the Engine Manufacturers Association andthe Outdoor PowerEquipment Associationindicatedthat component, field, engineering performance

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-86­

and emission testing programs conducted by manufacturers. could provide valuable information for detecting emission-related defects outside the emission warranty period.



### 8.6 Extension of 15 Day Reporting Deadline
8.6.1 Summary of Proposal Manufacturers are required to submit defect reports to the Agency not more than 15 working days after a confirmedemissions-related defect is found to affect 25 ormore engines ofa given engine family manufactured in the same certificate ormodel year. 

### 8.6.2 Summary ofthe Comments Manufacturers have requested the submittal period be extended from 15 days. to 20 or30 days, to allow the manufacturers to properly confirm and process defect information. and prepare and transmit the reports.


### 8.6.3 EPA.Response to the Comments The period for submitting a defect report starts once the manufacturerhas confmnedthat a defect exists. Therefore. the activities performed during this period shouldbe limited to transforming existing information into the form required by this regulation andmailing out the report. The activities to be performedby the non-road manufacturers during this proposed 15 day submittal period should not differ significantly from those undertaken by the on-highway manufacturers. The on-highway manufacturers have not expressedconcern with this reporting period overthe nearly 20 years that they have been subject to defect reporting requirements. The Agency has not been made aware ofany requirements unique to this industry which warrant an extension ofthe submittal period. As such. the submittal period will not be extendedbeyond the 15 day proposal.



### 8.7 Usefulness of Warranty Data
8.7.1 Summary of the Proposal Manufacturers are required to submit a defect report when an emissions-related defect is confmnedto existin 25 ormore engines ofa given engine family manufactured in the same certificate ormodel year.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-87­



### 8.7.2 Summary ofComments The Engine Manufacturers Association (EMA) and the OutdoorPowerEquipment Association (OPEl) stated that defect reporting regulations are not necessary because, even in the absence ofthese requirements, manufacturers are motivated to searchfor defects. Customer satisfaction requirements as well as the requirements ofother Agency programs provide this motivation. It was statedby EMA and OPElthat manufacturers will be able to determine defects, in the absence ofdefectreporting regulations, based on customer feedback, component testing, field test programs, EPA Selective Enforcement Audits, engineering performance and emission tests as well
as a number ofotherinformation sources. Furthermore, EMA and OPEl state that these sources will be much more likely to detect true defects than warranty dataalone, that warranty datais inaccurate, and that the process ofscreening the datato be more reliable is burdensome and not costeffective. EMA and OPEldoubt EPA can provide guidelines to help ease this screening burden. Defects caughtby the manufacturers will be repaired as early in the life ofthe engine as possible, long befor:.e any emission recall wouldbe instituted. Finally, the EMA and OPElcontendthat many emission-related defects which cause an increase in emissions are not perceivable to the owner, and therefore will not be caught by warranty.


### 8.7.3 EPA's Response to the Comments As stated previously, the manufacturers retain the defect determining function, not EPA. The Agency is notrequiring that warranty databe used as the sole means for identifying defects, and encourages methods which have served the manufacturers well in the past. This is the reason why the rule provides for manufacturers to determine defects by using procedures previously developed for safety and performance related-defects. The Agency encourages the use ofas many methods as possible for determining the existence ofemission-related defects. The Agency only requires that when a manufacturer confirms the existence ofan emission-related defect through one ofthese procedures, that the manufacturerprovide the Agency with a defect report. Based on the comments received, the defect report should merely be a compilation and formatting ofinformation generated through normal business practices. Manufacturers are encouraged to use warranty datato the extentpossible; EPAbelieves there are othervaluable uses for the databesides filing defect reports. The Agency would expect that manufacturers currently perform some sortofscreening ofwarranty 

### claims, once they reacha certain level, to verify the validity ofthe 

### claims, determine the cause ofthe problem, and feed this

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-88­

information into the product development cycle. Additionally, screening warranty data can

### be made less burdensome by using sampling plans for determining the existence ofdefects. Sampling plans minimize the scope ofthe warranty data that needs to 

### be screened. The Agency advocates the detection and repairofemission-related defects as early as possible in the engine life-cycle. Furthermore, the agency wishes to promote manufacturer initiated remedial campaigns. Forthis reason, the Agency concentrates its attention on those emissionrelated defects for which a manufacturerremedy has not been initiated. The Agency only requires that when the manufacturer, in accordance with this rule's definition ofan emission-related defect, determines that a defect exists and chooses to remedy the problemthrough direct owner notification, that the Agency receive a defect report and voluntary emission recall report. The Agency recognizes that some emission related-defects are not discernible to the owner and therefore are less likely to 

### be detected through warranty claim data. In these instances, the previously mentioned component, field, engineering performance and emission testing programs conductedby manufacturers, will provide valuable information for such detecting defects.



### 8.8 Dealer Concerns
8.8.1 Summary of the Proposal The rule requires that, at a minimum, manufacturers determine the existence ofemissionrelated defects using procedures established by the manufacturer to determine either safety or performance-related defects.


### 8.8.2 Summary ofComments The North American EquipmentDealers Association (NAEDA) statedthat dealers are well positioned to identify defects in equipment in the field, but are concerned that the defect reporting regulations could be interpreted to transfer liability to the dealers ifthey do not report such defects. Dealers need instructions onhow to release defective equipment for which owners refuse to pay for repairs. NAEDA also stated that ifdealers are to be used for tracking and reporting defects, recall and tracking systems must be in place before the regulations take effect.


### 8.8.3 EPA Response to the Comments The uSe ofdealers in determining andremedying defects would be a business agreement between the manufacturers and the dealers, as would the development ofany tracking, reporting,
orrepair systems. The Agency would generally support such an alliance and may provide advice if requested.

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However, the manufacturer, as the holderofthe certificate ofconfonnity, is solely liable underthe defect reporting regulations for detennining and remedying any emission-related defects. During the first two years ofthe defect reporting period, any emission-related defect would also be covered by the two-year emission warranty requirements. Therefore, any repairs to remedy an emission-related defect would be performed free ofcharge to the owner. Owners would be unlikely to refuse such repairs. Since engines will be outside ofthe emission warranty for the final three years ofthe defect reporting period, owners will be required to pay for any repairs performed to correct emissionrelated defects. Owners do have the right to refuse repairs, and ifthen choose to do so, the dealer will not be held liable for releasing the product without the repairs being performed. When a manufacturer decides to remedy an emissions-related defectthrough a voluntary recall program, the Agency will assure, through the voluntary emission recall report, that the remedy corrects the defect and any emission nonconfonnity itcauses, that the remedy does not result in engine performance problems, and that the remedy iseasily performedby technicians in the field. Requiring such conditions helps to avoid service-related returns and develops long term
consumerconfidence that corrective repairs, 

### in general, do not adversely affect engine performance. This in tum shouldreduce the percentage ofengine owners who are motivated to refuse such repairs.



### 8.9 Emission Defect Warranty Requirements
8.9.1 Summary of the Proposal The NPRM proposed that the emission defect warranty would be provided by engine manufacturers for the first two years ofengine use. EPA proposed to adopt the two year warranty period from California's lawn and garden regulations to reduce the burden ofmanufacturers having to administertwodifferent warran,ty programs. EPA solicited comments on the option for basing the warranty period on hours ofengine use instead ofyears. Employing such an option would require testing to detennine the equivalency ofhours to years and would require the installation ofa metering device to track the hours ofengine use. 

### 8.9.2 Summary ofthe Comments Comments were received from EMA, OPEl, Kubota, Kohler, and ECHO suggesting that the warranty periodbegin from the date offirst sale to the ultimate purchaser, rather than from the date the engine is first put into use. EPAunderstands that the date offirst purchaseby an ultimate
consumer is not necessarily synonymous with the date the engine is first put to use. Hence, it was

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-90­

EPA's intention that the warranty period would begin on the date offirst sale to the ultimate purchaser, not from the date the engine is first put into use, and extend for two years from the date ofsuch purchase. Comments were also received from EMA and OPElin favor ofbasing the warranty on hours ofuse for equipment where it wouldbe most practical. EMA and OPEl submitted data on two surveys conducted to determine the annual average hours ofoperation ofwalk behind and ride mowers, and their average lifespan. The results ofthe OPEl study conducted in 1990 show that walk behind mowers were operated on an average of22.4 hours per year with an average product lifespan ofsix years. In addition, ride mowers were operated on an average of39.8 hours per year with 

### art average product lifespan ofseven years. The results ofthe second survey, conducted in 1993 by another industry group, show that walk behind mowers were operated on an average of 20 hours per year with an average product lifespan offive years. Ride mowers were operated on
an average of34.5 hours per year with an average product lifespan ofsix years. EPA feels that these studies alone do not provide enough data to determine the equivalency between years from purchase and hours ofuse. In addition, it does not appear that the hours of operation for**comm~rcial** use equipment were taken into consideration when determining these numbers. Since, at this time, there is no readily available method for distinguishing residential use equipment from commercial use equipment, EPA's decision for Phase 1ofthese regulations is to base the warranty period on years from date ofpurchase by the ultimate consumer, and not on hours ofuse. This matter will be researched further in Phase 2. PPEMA feels that a two year warranty period is too long for commercial equipment and recommended a six month warranty period. As mentioned above, the twoyear warranty period
was adopted from California's lawn and garden regulations. CARB had determined the average product lifespan ofresidential and commercial utility equipment and, from that data, determined that two years is an appropriate warranty period for bothtypes ofequipment since twoyears is well below the average lifespan ofmost utility equipment. Once again, since there is no readily available method for distinguishing residential use equipment from commercial use equipment, EPA's final decision for Phase 1is to employ only one warranty period for both types of equipment. Othercomments received from PPEMA and ECHO suggest that the owner ofa small SI engine, subject to these regulations, be required to show proofofpurchase when making a warranty claim, that warranty claims arising from use ofnon-OEMreplacementparts orequipment abuse should be excluded, and that engine manufacturers shouldbe able to indicate acceptable replacement parts. PPEMA, Kubota, Kohler, and ECHO commented that warranty repairs should be performed by authorized dealers only. Finally, PPEMA requested that EPAtepublish a list of parts subject to warranty in the final rule.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-91­



### 8.9.3 EPA's Response to the Comments All ofthe issues raisedby the commenters are addressed in EPA's existing warranty policy for on-highway vehicles and apply to small nonroad engines accordingly as discussedbelow. EPA understands that, given the distribution system ofsmall nonroad equipment, it is difficult to track the purchase dates ofsuchequipment. However, EPA does not agree that, under every circumstance, owners should be required to show proofofpurchase when making a warranty claim. As a means ofresolving this issue, we encourage manufacturers to stress the importance offilling out and submitting warranty/registration cards that are provided at the time of purchase. If,when making a warranty claim, the owner does not have proofofpurchase, and a warranty/registration card was not submittedby the owner, the manufacturer should use the equipmentmanufacture date to reasonably determine ifthe engine could still be within the warranty period.The manufacturer may notrequire the use ofany specific brand ofparts in the maintenapce ofa nonroadengine. However, ifthe ownerofa nonroad engine uses replacement parts that are not ofequal quality to the original parts, and the replacement part causes another emission control
oremission related part to fail, the manufacturer would have a reasonable basis for denying emission warranty coverage. In addition, a manufacturer may deny warranty coverage ifthere is evidence that the failure resulted fromengine abuse, tampering orimproper maintenance. Warranty coverage may not be denied on the pasis that add-on parts have beenused, unless the add-on parts caused the failure. When seeking repairs under the emissions warranty, owners ofa nonroad engine must take the engine to an authorized dealer. Ifthe owner has a valid warranty claim, he or she may notbe charged for any costs associated with the repair orreplacement ofthe parts, including diagnosis of the problem, laborcharges, parts and miscellaneous items that are necessary to perform the repair. Ifthe owner is denied warranty coverageby an authorized dealer, but still believes he or she has a valid warranty claim, he or she may take the engine to an independent facility to have the repairs performed. In turn, the ownermay seekreimbursementfrom the manufacturer ifhe or she did in fact have a validwarranty claim. Consistent withemission control and emission related parts on EPA's July 15, 1991, parts list for motorvehicle warranty coverage, and CARB's warranty parts list for utility and lawn and garden equipment, EPAprovides the following parts list for design anddefect warranty coverage:
(1) Fuel Metering System (i) Carburetorand internal parts (or fuel injection system). (ii) Air/fuel ratio feedback and control system.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-92­


### (iii) Cold start enrichment system. (2) 

### AirInduction System (i) 

### Controlled hot airintake system. Oi) Intake manifold.
(3) Ignition System (i) 

### Spark Plugs. (ii) 

### Magneto orelectronic ignition system. (iii) Spark advance/retard system.
(4) Exhaust Gas Recirculation (EGR) System (i) 

### EGR valve body and carburetor spacerifapplicable. (ii) 

### EGR rate feedback and control system.
(5) 

### AirInjection System (i) 

### Airpump orpulse valve

.. (ii) Valves affecting distribution offlow. (iii) 

### Distribution manifold.
(6) Catalyst ofThermal Reactor System (i) Catalytic converter. (ii) Thermal reactor. (iii) Exhaust manifold.
(7) 

### Particulate controls (i) 

### Traps, filters, precipitators, and any otherdevice used to capture particulate emissions.
(8) Miscellaneous items used in the above systems (i) 

### Vacuum, temperature, and time sensitive valves and switches. (ii) 

### Electronic controls. (iii) 

### Hoses, belts, connectors, and assemblies.

Each manufacturer shall provide a copy ofthe 

### above parts list to the ultimate consumer, using those portions ofthe list applicable to the engine.

Emission Slandards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-93­


### 8.10 Independent Commercial Importer (ICI) Program
8.10.1 Summary of the Proposal The Agency proposed options ofhaving an ICI programparalleling that ofthe on-highway program, and having no ICI program in the final rule.


### 8.10.2 Summary ofthe Comments The Agency received comments from three parties: PPEMA, ECHO and CARB. All commenters supported EPA's second option ofnot including an ICI program in the final rule, and
no comments were received suggesting that an ICI programbe promulgated.


### 8.10.3 EPA's Response to the Comments EPA is therefore not promulgating an ICI programin the final rule.



### 8.11 Tampering
8.11.1 Summary of the Proposal EPAbelieves that an engine is more likely to continue to meet the applicable emissions standards in use ifthe engine maintains its certified configuration. Therefore, the NPRMproposed anti-tampering provisions which would make. it illegal for any person to tamper with any emission control oremission related component, or system, installed on orin a small 81 engine subject to these regulations.


### 8.11.2 Summary ofthe Comments Comments were received from EMA and OPEl which suggested that EPA adopt CARB's

. approach with regard to making adjustable engine parameters tamperresistant.


### 8.11.3 EPA's Response to the Comments EPA agrees that emission control components, emission related components, and adjustable engine parameters should be made tamperresistant to the extent possible. This will help
ensure that engines meet the applicable emissions standards in use.



### SECTION 9: ECONOMIC EFFECTS

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-94­



### Summary of the Proposal The proposal estimated that, on average. the cost to engine manufacturers to install the necessary emission control technology would be approximately $0.80 to $1.13 perengine for nonhandheld equipment and approximately $2.05 to $2.20 per engine for handheld equipment, assuming catalysts were not required. Should catalysts actually be used on some portion of production. EPA estimated that the additional variable hardware costs would be $1.09 per nonhandheld engine and $0.10 perhandheld engine, with an additional $0.24 perengine for equipment modifications and $0.20 per engine for potential heat shielding. These additional costs
are averaged across the entire production ofeither handheld ornonhandheld engines, including those not needing catalysts. The increase in retail price was estimated to be $2.35 for nonhandheld equipment and $4.04 for handheld equipment. assuming no use ofcatalysts. When fuel reductions and lowered maintenance costs were considered, the lifetime consumer cost impact was estimated to be even less, with nonhandheld equipment actually realizing a net lifetime savings for the consumer. 

### Summary ofthe Comments Comments were received from engine and equipment manufacturers, dealers, and their organizations, as well as one City government. Manufacturers and their organizations generally felt that the estimates were too low or that some costs had been overlooked. In general, however, these commenters did not supply their own estimates for the questioned values. Chicago commented on the impact ofthe costs rather than the costs themselves, indicating that the costs could unduly burden local government entities that must purchase large quantities ofequipment for city maintenance.189 Specifically, PPEMA commented that the $4.04 consumercost increase for handheld equipment was extremely optimistic, and ignored redesign and production realities. They also commented that CARB's projection was higher.190 OPEl also commented thatretooling costs and supplemental label costs were not considered.191 Onan agreed that some costs were overlooked. commenting that, "The EPA must also consider the development costs (both labor and infrastructure), the costs ofretooling, changing software, changing product literature, testing, and reporting as required by the regulations."192 EMA also felt that the projected costs were too low,
as did NAEDA, Tecumseh, and ECHO.193,194,195,196 Tecumseh and Onan felt that the catalyst costs were especially offthe mark. NAEDA argued that the costestimates should include changes to lifestyle prompted by equipmentchanges. Like Chicago, they commented that the cost impact of the regulations on governmental agencies that mustpurchase anduse large quantities oflawn, garden and utility equipment shouldbe considered.

Emission Standards for New-Nonroad Spark.-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-95­



### EPA's Response to the Comments The cost estimates, which are providedbelow and in more detail in the RSD, have been slightly revised since publication ofthe proposal. Revisions were made to include supplemental label costs, which were indeed overlooked, and to reflect changes in the final rule that affect average costs, such as the added flexibility in the implementation date and the loosening of standards applicable to two-stroke lawnmowers and two-stroke snowthrowers. In general, however, the Agency has retained its costestimates, largely because they were based on industry submittals ofthe netcost increases industry expected to incur due to this regulation, for which commenters did not provide alternative estimates in their latercomments on the proposal. Commenters are mistaken that certain costs, such as those for retooling, were not included in the estimates. In fact, as detailed in the RSD, the Agency has considered all ofthe costs mentioned by commenters, except for supplemental label costs, which have now been added, and changes in product literature and software. TheEPA sees no reason that product literature and software would incur net increases incost, as these are regularly updated. Additionally, these categories were not included in the confidential cost submissions from manufacturers used in developing EPA's estimates, and EPA is not in a betterposition than the manufacturers to estimate them or claim that they would be net increases. For other costs, commenters stated that EPA's estimates were too low but, unfortunately, did not provide revised estimates. Since EPA's values in the proposal were based oncostestimates submitted by the industry itselfpriorto the proposal, and since no revised estimates were laterprovided, the EPA is not in a position to revise its estimates. Please referto the RIA for a detailed listing ofall costs considered in analysis ofthe emission standard levels. The Agency does not agree with NAEDA that this rule would cause negative consequences to lifestyle that should be assigned a cost value. The Agency does not expect product utility tobe decreased by this regulation, nor are consumers required to make any changes whatsoever to their current equipment, to replace equipment, orto reduce their use ofthese products. Infact, there should be some lifestyle improvements for the equipment user, as fuel use and equipment maintenance needs are expected to improve as a result ofthe technology changes prompted by this

. rule. The public as a whole is also expected to enjoy lifestyle improvements ratherthan detriments due to airquality improvements. The only lifestyle impactthe Agency can envision NAEDA as referring to is the change from two-stroke to four-stroke engines in some types ofequipment. While some would view this as an overall negative, others would view it as positive, even regardless ofthe air quality improvements ofsuch a change, so that the net result on lifestyle is unclear; in any case, the Agency has no information with which to place a dollarvalue on the effects ofsuch a change.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-96­

The Agency is sympathetic to comments from Chicago and NAEDA that the impacts of such changes on governmental entities should be considered. In fact, the Agency considered the monetary effects on all users when setting standards and developing the provisions ofthe rule. It
was clearly necessary, given the mandates ofthe CAA and the results ofthe Nonroad Study, to regulate the emissions from these engines. The Agency has done so in this Phase 1rule very costeffectively. In fact, the cost-effectiveness ofthis rule is significantly better than that ofmany other mobile source programs, such as additional requirements on automobiles, which are also purchased by governmental entities. The Agency continues to believe that the requirements ofthis rule are very cost-effective, with the gains to the public worth the very small marginal cost to governmental units and otherconsumers ofsmall engines. Finally, as described below, the fuel
use andequipment maintenance improvements engenderedby this rule shouldbeofsignificant benefitto governmental entities using large quantities ofsuch equipment. The total national average annual.cost ofthis rule is estimatedto be approximately $70 million. Ifcatalysts become necessary, the average annual cost is estimated to be approximately $87 million. The net present value ofpollution control capital costs is estimated by EPA to be approximately $28 million. Energy impacts are expected to be positive, freeing up approximately $8 million for other uses in the economy. The following summary presents aggregate costs broken downby engines used in nonhandheld and those used in handheld equipment. Forgreater detail ofexpectedcost impacts,
see the RSD. Industry will bearpollution control costs that are moderate: roughly six percent for handheld and two percent for nonhandheld equipment relative to currentproduction costs. The level ofpollution control costs is largely due to the high levels ofpollution emittedby these engines, especially two-stroke engines, and the relatively outdated state ofthe technology compared to on-highway engines. However, the costs are still small in absolute terms, and it is anticipated that these costs will be passed through to consumers in higher product prices. The Agency estimates that there will be no long run negative impacts onemployment as a result ofthis rule, as costs canbe recovered through increased prices. Any potential decreases in employment that might occurdue to obsolescence ofproduct line shouldbe offsetby increased production ofengines meeting emission standards. Total demand for these products has traditionally been relatively inelastic and, thus, industry sales volume is not expected to decrease. On average, the cost to the engine manufacturerto install the necessary emissioncontrol technology will be approximately $2per engine used in nonhandheld equipment and $3.50per engine used in handheld equipment. This includes variable hardware and production costs, assuming that catalytic converters will not be needed to comply withproposed standards. However, engine manufacturers may voluntarily decide to use catalysts on a percentage ofengines

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-97­

at risk ofonly marginally complying. Should this occur, EPA estimates that the additional variable hardware costs will be about $4percatalyst-equippedengine used in nonhandheld equipment and $3 per catalyst-equippedengine used in handheld equipment. Since catalysts are not expected to be used much, the overall sales-weighted average increase due to catalyst usage is estimated to be about $1 for engines used in nonhandheld equipment and marginal for engines used in handheld equipment. It should be noted that the costs between manufacturers will likely vary. Consumers will find small increases in retail prices for most equipment powered by these engines. The initial purchase price to the consumer will, however, be partially or, in some cases, completely offset by savings in fuel and maintenance costs. Thus, over time, environmentally friendly equipment will become less costly to consumers. The retail price ofequipment that uses nonhandheld engines ranges from $90to $9,000, and the retail price ofequipment that uses handheld engines ranges from $60to $ I,000. The salesweighted average increase in retail cost to the consumerdue to the rule in 2003 is estimated to be about $5 for nonhandheld equipment and $7 for handheld equipment. Ifcatalysts are necessary, the values in 2003 are about $7 for both nonhandheld and handheldequipment. The retail price effects for a specific engine will likely be more orless these values, depending on the technology ofthe engine; these are average, sales-weighted costs, not indicative ofthe price increase specific to any particular manufacturer's engine orequipment. This rule is expected to decrease fuel consumption significantly. The average salesweighted engine is expectedto experience a 

### 26 percent decrease in fuel consumption for nonhandheld equipment and a 13 percent decrease in fuel consumption for handheld equipment. These decreases are translated into small discounted lifetime sales-weightedfuel savings of approximately $3 for nonhandheld equipment and marginal for handheld equipment. EPAexpects that the engines produced to meet the proposedemission standards will be of higher quality than current engines: the parts and raw materials will be more durable and less likely to malfunction, as discussed in the RSD. This will result in equipment that is operational a higher percentage ofthe time and that lasts longer, although EPAis unable to quantify the attendant decrease in consumercost orincrease in useful life at this time. EPArequested comments on the potential decrease in maintenance costs and increase in useful life, but none were received that shed light on this topic. Considering that the fuel savings offset the average increase in retail priceperengine, the average sales-weighted lifetime increase in cost will be about $6.50per handheld engine, while nonhandheld engines will realize a lifetime savings ofabout $2.50 perengine. This does not include the lifetime savings in maintenance costs, which will further benefit the consumer. Based upon the costs and benefits described above, EPAhas prepared a cost-effectiveness analysis and has performed a Regulatory Impact Analysis (RIA) for this proposal, which is

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-98­

contained in the RSD. Presented here is a summary ofthe cost-effectiveness ofthe small SI engine Phase 1program, assuming catalysts are not used. In addition, these cost-effectiveness numbers
are based on the assumption that manufacturers ofengines used in snowthrowers and ice augers will opt to certify such engines to meet the applicable HC standards. To the extent that this does not occur, estimated cost impacts to both industry and conumers would be slightly reduced, and the cost-effectiveness ofthe program as a whole would not be significantly changed, ifat all. Ifall programcosts are allocated to HC, this rule has a cost-effectiveness of$266 perton ofHC reduced. Alternatively, ifall program costs are allocated to CO, the cost-effectiveness is $107 perton ofCOreduced. 

### Ifthe costs ofthe program are equally splitbetween HC and CO, the cost-effectiveness is $133 perton ofHC reduced and $54 per ton ofCO reduced. These cost­

. effectiveness numbers are significantly lowerthan costs perton ofother available control

strategies. The cost-effectiveness estimates, underlying quantitative methodology, and comparisons to other available control strategies are explained further in the RSD. 

### In summary, the cost-effectiveness ofthe rule is favorable relative to the cost-effectiveness ofseveral othercontrol measures required under the Clean Air Act. To the extent that costeffective**nationwid~** controls are applied to small SIengines, the need to apply more expensive additional controls to othermobile and stationary sources of

### airpollution may be reduced inthe future.



### SECTION 10: ADMINISTRATIVE REQUIREMENTS



### 1O. 1 Small Entities
10.1.1 Summary of the Proposal 

### In its proposal, EPAdetermined that this rule will have an impact on small entities and, therefore, tailored this rule to minimize cost burdens on smallerengine manufacturers by minimizing theircertification, SEA, and in-use testing requirements. 197 The Agency also dramatically limitedthe requirements on equipment manufacturers utilizing small SIengines by making the use ofnon-certified engines a prohibited act (with its attendant penalties) rather than requiring equipment manufacturers to report to EPA that they are using certified engines. The Agency considered, but rejected, the notion ofexempting small manufacturers from enforcement programs orfrom the regulation entirely. It determined that a more proportionate sharing ofcostburden is more appropriate. The pollution emitted by each ofthese engines not

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-99­
only contributes to ambient air quality problems, but also has health impacts on the user ofthe equipment who is in close proximity to the exhaustemissions. (See the Regulatory Support Document for a discussion ofthe health impacts ofthe related exhaust pollutants.)


### 10.1.2 Summary of the Comments Certain manufacturers ofequipment incorporating small engines ofthe types regulated in this action described themselves in theircomments as "captives" ofthe small engine manufacturers, since the equipment manufacturers buy engines from the small engine manufacturers to build their equipment. These commenters argued that, as captives ofthe regulated industry and as small businesses, the options analysis should be extended to covertheir needs, including consideration for exemption from the rule. Theirprimary concern was the potential for the elimination oftheir two-stroke engine source. 

### In particular, they feared that the engine manufacturer would choose to not invest in upgrading the two-stroke engines used in augers to meet the emission standards, since they are produced at low volume.


### 10.1.3 EPA's Response to the Comments The Agency-rejected the interpretation ofthe small entities provisions as extending to buyers ofthe coveredengines as "captives," since in most cases the equipment manufacturers have the option ofswitching to engines whichcan comply with the new standards; nevertheless, EPA did considertheir position in its deliberations concerning the final rule. The two-stroke auger engines are also used in two-stroke snowthrowers. Given that EPA is allowing both two-stroke snowthrowers and one-person augers to use engines that meet the handheld CO standards, these engines will continue to beproduced in sufficient volume to make them economically viable. Moreover, the Agency is extending the exemption for snowthrowers from the requirement to certify to HC standards to ice augers, since bothofthese products are used exclusively during the winter when ozone concentrations do not present as much ofan environmental concern. EPA expects, however, that manufacturers ofengines used in snowthrowers and ice augers will generally opt to certify to HC standards, due to the availability ofcomplying technology and the market advantages of "green marketing." The Agency believes that the revisions to the rule allowing two-stroke snowthrowers and one-person augers to meet the handheld CO standards and not requiring snowthrowers andice augers to certify to HC standards adequately address the
concerns ofthe commenters.



### 10.2 Reporting Burden
10.2.1 Summary of the Proposal

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95100­

In the Information Collection Requests developed to support the NPRM, the Agency estimated that a typical manufacturer may expect to spend 6,100hours annually to comply with the testing, record keeping, and reporting requirements proposed in the rulemaking. This estimate of the hours spent by a manufacturer on information collection activities in any given year is highly dependent upon manufacturer specific variables, such as the number ofengine families, production changes, and emission defects.


### 10.2.2 Summary ofthe Comments Some manufacturers commented that the estimated public reporting burden of6,100hours peryearis a large burden for a "typical" manufacturer. They argued that ifthe defect reporting, production quality audit reporting and in-use test reporting remain as proposed the impact will be greaterthan estimated. These manufacturers suggested that harmonization with CARB should minimize the burden. [Tecumseh Products Co., 

### 8/5/94, Docket No. A-93-25, IV-D-28 and Onan, 

### 8116/94, Docket No. A-93-25, IV-D-34]


### 10.2.3 EPA's Response to the Comments The Agency_ shares the commenters' concerns and recognizes that the burden associated with the testing, record keeping, and reporting requirements is not trivial. In developing this rulemaking, the Agency drew on more than twenty years ofexperience with the on-highway programs to identify the most critical items for inclusion in these requirements. The Agency made everyeffort to minimize the burden while assuring that the resulting regulatory programwill be implementable, overseeable, and enforceable. With respect to the burden estimates, as a general rule where there was uncertainty the Agency tried to overestimate the burden sothe analytical results represent the upperrange ofthe potential burden. Finally, the Agency concurs with the commentregarding harmonization with CARB and to the extent practical, the Agency has done so.



### 10.5 Health Effects/Air Toxins
10.5.1 Summary of the Proposal The Agency requested additional information onthe effects ofair toxics and CO exposure associated with the use ofsmall SIengines.


### 10.5.2 Summary ofthe Comments Inits comments, PPEMA argued that no existing studies show that operation ofhandheld products has resulted in negative health effects. STAPPA requested that EPA devote time to study the health effects and inthe meantime to errinthe direction ofincreased operatorhealth protection.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-101­



### 10.5.3 EPA's Response to the Comments The Agency appreciates the commenters concerns. The Agency did not receive additional information on the effects ofair toxics and COexposure associated with the use ofsmall SI engines, and accordingly retains the position taken in the proposed rule;


### 10.6 Modeling
10.6.1 Summary of the Proposal EPA presented calculations ofemission benefits from the Phase I regulation based on nationwide sales.


### 10.6.2 Summary ofthe Comments NAEDA suggested subtractingthe benefits from the CARB rulemaking along with the cost ofthe CARB rulemaking. Ifhowever, the costs ofCARB studies are to beremoved to satisfy·the estimation ofPhase 1costs, then too, the benefits derived from CARB rules shouldberemoved from the measurement ofPhase 1benefits.


### 10.6.3 EPA's Response to the Comments EPA had subtracted costs in the NPRM costfbenefit analysis due to the workthat engine manufacturers will have done before this rule is finalized. The emissionbenefits from CARB's rule had not been subtracted in the NPRMcostfbenefit analysis. Forthe Final Rule, EPA has subtractedemission benefits for CARB's small engine rulemaking based on documented California sales estimates (as published in CARB's Technical support document) applied to the EPA inventory model.



### 1 0.7 Estimate of Use of Fixed Jet Carburetors for Class V
10.7.1 Summary of the Proposal The Phase I RIAlRSD for Small SI engines assumes that 50percent ofClass V engines will use fixedjetcarburetors as engines use the technology ofenleanment to meetemission standards.


### 10.7.2 Summary of the Comments PPEMA stated that 7.5 percent, not 50**perce~t,** ofClass V engines will use fixedjet carburetors. EPA's assumption that 50percent ofClass V engines will use fixedjetcarburetors to

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-102­

avoid the need to use limiter caps is unrealistic because perfonnance and emissions requirements of professional handheld equipment requires some flexibility in the air/fuel mixture, thus eliminating widespread use offixedjetcarburetion.



## ,. 10.7.3 EPA'S Response to the Comments Based on this commentEPA agrees to change the estimate ofClass V engines which will
use fixedjetcarburetors to 7.5 percent from 50 percent.



### SECTION 11: ADDITIONAL ISSUES

11.1 Absence of Averaging, Banking and Trading Programs
11.1.1 Summary of the Proposal 

# • The Agencydid not propose an averaging. banking. andtrading program (ABT) for new small SIengines. Such market-basedincentive programs canreduce the cost ofcontrolling emissions, and have been utilized increasingly byEPA in recent rulemakings. Forexample, EPA does allow ABT in its on-highway heavy-duty engine program and in the new nonroad large CI engine program, because it believes that ABT programs provide manufacturers necessary flexibility in meeting the emission standards. However, EPA did not propose an ABT program for new small SIengines due to the uncertainties surrounding projectedin-use emission levels. The Agency explained that, unless all engine families deteriorate at the same rate, EPA must have data on the in-use emission characteristics ofspecific small SIengine families in orderto determine how ABTcredits and standards shouldbe set. The lifetime emissions ofengine families must be averaged together in order to compute the average emission level ofa manufacturer's product line. Knowledge of lifetime emissions is necessary because it may bethe case that the emissions ofone type ofengine deteriorate at a higher rate than anothertype, or a smallerengine may deteriorate at a higher rate than a larger engine ofthe same type, with the result that lifetime emissions may vary in ways not predictable from data on new engines alone. The Agency stated in the proposalthat it is not in a position to determine what in-use emission levels presently are, let alone what they would be under this Phase I regulation. The Agency's initial assessment was·that the emissions ofthese engines deteriorate somewhatover time and likely deteriorate at different rates between engine families, but that more research is necessary.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-103­

The limited information available to EPA atthis time is primarily derived from engines currently on the market that may not adequately predict deterioration oftheemissions ofengines modified to meet Phase I standards.


### 11.1.2 Summary ofthe Comments The Agency received four comments in supportpfEPA'sproposal to not include ABT and three in favor ofimplementing ABT for small SIengines. Commentsjointly submittedby EMA and OPEl maintained that the advantages ofan ART programrecognized by EPA in the preamble outweighconcerns about uncertainties regarding in-use emission characteristics.l98 They pointed outthat an ABT program is a meansto preserve availability ofcertain engines that would have difficulty meeting the standards and which are not easily replaceable in some specialty applications

.

.Theircomments described an outline for a small SI engine ABT program, consisting of(1) family emission limits for each exhaust constituent, (2) no averaging, banking. ortrading across classes, (3) creditbased on certification data only, with the assumption that all small SIengines deteriorate at the same rate within eachclass, (4) early banking, (5) trading between manufacturers, and (6) Phase I credits transferable to Phase 2, orifPhase 2 did not employ**ABT~** creditexpiration after Phase 1. Like EMA and OPEl, PPEMA supported an ABT program as being advantageous, even in the light ofEPA's concerns overthe uncertainties regarding in-use**emissions~** however it proposed
a different program than thatoutlined by EMA and OPEI.l99 PPEMAcharacterized its proposal as being similar to the one adopted in EPA's rulemaking on nonroad CIengines over 39 kW (50 hp).200 The PPEMA proposal for an optional ABT program would include: (1) corporate-wide averaging, (2) family emission limits, with caps for the highest permissible family emission limits, (3) limited credit life, and (4) an option to establish a phased decrease in corporate-wideemissions, requiring that a manufacturerreduce its total calculatedemissions by specifiedpercentages over a set timetable. Briggs 

### & Stratton submitted a report by National Economic ResearchAssociates, Inc. (NERA) it hadcommissioned in conjunction with its request that EPA add an ABT programto the small SIengine rulemaking.201 The NERA report illustrates the potential gains ofaveraging, and how they can be extended-through banking and trading. This illustration showed how a manufacturer seeking to reduce its product lines' aggregate emissions by a given targetpercentage would be able to do so either with orwithout averaging, but that the target percentage couldbe achieved at a lower costunder an averaging regime. Forexample, a manufacturercouldchoose to attain a given percentage reduction in its aggregate fleet emissions by accounting for all the reductions among those engine families least costly to control, and nothaving to control the rest of its engine families. Briggs & Stratton argued that this would allow the same percentage of

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-104­

aggregate fleet emissions reduction to be attained as couldbe achieved ifeach engine family had to individually accomplish that percentage reduction, but at a lowercost. Briggs and Stratton also cited the success ofother ABT programs. It stated that, without ABT, the company might not be able to continue production ofits full product line, and as a consequence, may have to reduce its workforce. Finally, it maintained that it had no reason tobelieve thatemission factors would be biased one way orthe other, and absent any bias to overstate emissions, an ABT program should be workable. One industry association, MECA, commentedin support ofEPA's position on ABT.202 It agreed with EPA's viewthat an effective ABTprogramcannotbedeveloped given the uncertainty about in-use emissions, especially in the absence ofany in-use provisions. While MECA expressed concerns about the general effectiveness ofABTprograms, itindicated it would be appropriate for EPA to consider ABT in the contextofPhase 2. In its comments, CARB supportedEPA's contention that an ABTprogramis not necessary for Phase 1, because the relative stringency ofPhase 1 standards is such that use of significantly advanced or costly technologies will not be required for manufacturers to achieve compliance.203 Despite having

### beel! petitioned to include averaging in its small nonroad engines program, CARB has declined include it. BecauseEPA seeks consistency with CARB's regulations whenever it
seems appropriate andpracticable, CARB's reluctance to employ ABT at this time reinforces EPA's decision not to incorporate ABT in Phase 1. A very strong argument against incorporating ABT from STAPPAI ALAPCO made five points: (1) questions concerning the certification test's ability to differentiate between various technologies withoutbias, (2) the variability ofsmall engine emissions, even when new, (3) uncertainties regarding the rate, shape and level ofdeterioration ofcurrentengines, (4) uncertainties regarding the rate, shape and level ofdeterioration ofPhase 1engines, and (5) the absence ofin-useenforcement.204 Moreover, NRDC pointed outthat incorporating an ABTprogramwould necessitate adjustment ofthe standards to more stringent levels ifthe projected emissions decreases were to be realized.205 It argued that adding ABT without revising the standards would allow the aggregate emissions to increase overlevels projected for small SIengines in the absence ofABT.


### 11.1.3 EPA's Response to the Comments It is EPA's experience that someproportion ofengine families will exhibitemission levels lowerthan what is necessary to establish a "safety margin" that allows for test-to-test and engineto-engine variability. Therefore, when all engine families mustindividually meetthe standard, the averagedemissions will lie at some pointbelow the level corresponding to the averaged safety margin. However, when engine families need only meet the standard in the aggregate, fleetwide

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average emissions may lie at levels as close tothe standards as possible (even taking into account that there is still a safety margin below each family emissions limit that prudent manufacturers will maintain). This consideration is not problematic in and ofitself; the problem arises when ABT is incorporated only after settling upon appropriate standards. Because adding ABT without revising the standards effectively weakens the standards, EPAdecided against including such a program in this rulemaking. IfEPA were to opt to include ABT as a feature ofthe Phase 2 rule, the Phase 2 emission standards would be determinedtaking this factor into account. While itis possible that an ABT program would encourage manufacturers to bring forward technological advancements in emission control for the purpose ofgarnering credits, NRDC has argued that no one has produced analytical support for this position.206 No manufacturer has given any fIrm indication that it would implement specifIc technological advancements soonerif EPA adopts ABT in this rulemaking than it would otherwise. Even ifit had no concerns regarding the potential for increasedemissions, EPA would not consider it appropriate to approve an ABT program for new small SI engines at this time, because EPA has not encounteredevidence that would convince it that approximately equal rates of deterioration occur !n use across engine families. The argument advanced by PPEMAthat uncertainties concerning in-use emissions "did not prevent EPA from adopting an AB&Tprogram for new nonroad diesel engines over 

### 50 hp"207 is not convincing, because much more is known about in-use emissions ofthe large CI (diesel cycle) engines coveredbythat rulemaking than is known about the in-use emissions ofsmall Sfengines. Many ofthe engines covered by the nonroad large CIengine rule are the same or very similarto those currently regulated under the ongoing certifIcation program for heavy-duty engines and vehicles; therefore, PPEMA's comparison between EPA's approach to nonroad large CIengines and its approach to nonroad small SIengines is not an apt one. These uncertainties will be resolved as part ofthe Phase 2 regulatory negotiations. Phase 2 will directly assess in-use emission characteristics ofengine families and incorporate enforcement ofin-use emission levels. Once in-use emission levels are known with more confIdence, EPA expects that market-basedprograms such as ABT will be viewed more favorably by the regulatory negotiation committee during policy development. Finally, in response to Briggs & Stratton's contention that ABT could produce the same aggregate emissions reductions achievable withoutthe program, EPApoints out that its program
was not set up the same way as Briggs & Stratton's example, and is not easily adaptable to it. The Agency's standards are defIned in terms ofdiscrete emission limits, rather than percentage reductions in emissions. To allow averaging within a scenario involving emissions standards, family emission limits could be designated such that the fleets would have to meetthe standard only in the aggregate. As described in the precedingparagraphs, the nature ofan averaging

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-106­

scheme is such that aggregate emissions are expected to be higher in such a scenario than when eachengine family must individually meet the standard. IfEPA were to adopt more stringent standards to compensate for this. orchange to percent emissions reductions on the aggregate scheme like that proposed by Briggs & Stratton. it would have to generate a supplemental proposal and allow comment on this fundamentally different approach to regulating nonroad small SI engines. Again. EPA does not wish to delay promulgation ofthe Phase 1standards unnecessarily, but will considerthese arguments ifraised during deliberations for the Phase 2 regulations. IfEPA
were to opt to include ABT as a feature ofthe Phase 2 rule. the Phase 2 emission standards would be determined taking this factor into account.



### 11 .2 Administrative Procedure Act
11.2.1 Summary of the Proposal EPA stated in the proposal that the proposed regulatory language was not included as part ofthe Federal Register notice. but was available for free on computerdiskette. via an electronic bulletin board.orat'the EPA

### Air Docket. The NPRM provided explicit directions to aid the public in obtaining the regulatory language from anyone ofthese sources.


### 11.2.2 Summary ofthe Comments Holliday Environmental Services submitted comment that EPA's failure to publishthe regulatory text for the NPRM contravenes the Administrative Procedures Act.208


### 11.2.3 EPA IS 

### Response to the Comments EPAhas determined that regulatory text for an NPRM does not have to be published in the Federal Register in orderto meet the requirements ofthe Administrative Procedures Actor the Clean Air Act. 5. U.S.c. § 553(b) requires that general notice ofproposed rulemaking be published in the Federal Register. which shall include eitherthe terms or substance ofthe proposed rule or a description ofthe subjects and issues involved. Where EPApublishes a notice of proposed rulemaking that describes the subjects and issues involved it is not required to publish the proposed rule text. Moreover, today's rule is subject to the procedural requirements ofClean Air Act section 307(d), not the Administrative Procedures Act. 42 U.S.C. § 7607(d)(1)(R). That provision requires EPAto publish notice ofproposedrulemaking, accompanied by a statement of its basis and purpose. but does not require EPA to publish proposed regulatory text. Id.• 7607(d)(3).

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95107­


### 11.3 SIP Credits
11.3.1 Summary of the Proposal The proposal didnot discuss this issue, but in the CaliforniaFederal Implementation Plan (FIP) the Agency allows States to include credits in their attainment State Implementation Plans (SIPs) from yet to be promulgated regulations establishing national nonroad engine emission standards.


### 11.3.2 Summary ofthe Comments The Natural Resources Defense Council (NRDC) commented that"

...Supplying hypothetical IIcredits" to States can not ensure that areal reductions (sic) will occur. Instead, such policies impede attainment by allowing States to include unquantifiable and unenforceable
measures in their implementation plans, instead ofactual regulations that can deliver quantifiable pollution reductions

... "209


### 11.3.3 EPA's Response to 

### the Comments The Agency.acknowledges that for the national nonroad regulatory program and the small engine and marine pleasure craftprograms in particular, the projected benefits are not exact since in bothcases they depend on public comment to proposed rules and in the case ofthe smallengine standards, they will also dependin part on the outcome ofthe regulatory negotiation process (for Phase II). However, the promulgation ofmost ofthese rules is imminent and all are legally compelled by specific dates. Therange ofuncertainty with regard to the benefits ofthe fmal rules is small, especially in comparison to the total emissions inventory. Consequently, the potential
errorin inventory estimates and therefore, the potential error in the required stringency for all other control measures in the nonattainment areas, is smalL It is EPA's position, with respect to national programs and given certain conditions are met, that states may take an approach in their SIPs that is similar to that allowed in the California FIP. The fact that these nonroad rules are required Federal rules, and indeed with court-ordered deadlines, creates special circumstances that allow EPAto considerthem enforceable SIPelements, provided states also commit to adopt gap-filling measures to account for any shortfalls, identified later, between currently anticipated and actual final rule benefits. These gap-filling measures do not necessarily have to be in the same inventory category as the rule for which they are meant to account. States must also be aware that implementation ofadditional programs within the nonroad category to compensate for any shortfalls in fmal federal nonroad enginerules may be very difficult. States may, therefore,wishto discount credits for these programs in their SIPs as a safety margin against potential shortfalls when these rules are finalized.

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The Agency has concluded that this policy ofauthorizing SIPs to take credit for reductions from Federal measures is consistent with the overall scheme ofthe Clean Air Act ozone nonattainment provisions, as well as the relevant provisions by their terms. Congress anticipated that attainment ofthe ozone primary national ambient 

### airquality standard would result from a combination ofState and Federal actions. As a result, the reductions from Federal measures are an integral part ofCongress's blueprint for attainment. Therefore, SIPs should be allowed to account for those reductions. In particular, the attainment demonstration provisions ofsections 183(b)(1)(A)(i) (Moderate areas) and 182(c)(2)(A) (Serious and higher classified areas); as well as the rate-of-Progress (RaP) provisions ofsections 182(b)(1)(C) (initial 15 percent required reductions) and 182(c)(2)(B) (subsequent 3 percent per yearrequired reductions) may be read to
assume the creditability ofreductions from Federal measures (other than those specifically identified in the Rapprovisions as noncreditable). Further, denying SIP credit for reductions from Federal measures would unduly burden the States because States would be obliged to develop andbegin to implement SIP measures to assure the full amount ofreductions needed for Rapand attainment, but they could subsequently retract those SIPprovisions when theFederal
measures are promulgated and begin yielding reductions. Further information and guidance on this issue may be found'in the AirDocket; specifically, refer to documents numbered A-93-25, IV-J-Ol and IV-J-02.



### 11.4 Metric
11.4.1 Summary of the Proposal Metric units are used throughout the proposed rule without English equivalents. This was done in compliance with the Metric Conversion Act of 1975, as amended, and Executive Order 12770, July 25, 1981, which directs all federal agenciesto use metric as the primary unit in regulations by September 30, 1992 and to only provide English equivalents when the affected party(s) uses English as the primary unit. In the NPRM, EPA solicited comments on the impact ofusing only metric units orthe need for including the English equivalent.


### 11.4.2 Summary ofthe Comments Inits comments, NAEDAexpressed concernthat although manufacturers may use metric without English equivalents, equipment dealers and users usually use English as the primary unit21O• NAEDArequested that equipment specifications be stated in English for the United States marketplace.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95109­



### 11.4.3 EPA's Response to the Comments EPA has decided to retain metric measurements for the final rule. This does not preclude the additional use ofEnglish equivalents by manufacturers to provide darity for equipment dealers and users.



### 11 .5 Service Information
11.5.1 Summary of the Proposal There was no mention ofservice information in the NPRM.


### 11.5.2 Summary ofthe Comments A comment was received from NAEDAexpressing concern overthe availability of necessary service information and suggesting that EPA address this topic in the forthcoming regulations.211


### 11.5.3 EPA"s Response to the Comments Service information requirements were not proposed in this NPRM. They are outside the scope ofthis action and cannot be included in the FRM.



### 11.6 Consumer/Commercial Terminology
11.6.1 Summary of the Proposal EPA proposed to adopt a "class" structure for the Phase 1regulation. Inthe NPRM, EPA explained that this rule proposed two broad use categories--nonhandheld and handheld. Nonhandheld engines would be required to meeteither Class I orClass II standards while handheld engines would have to meet eitherClass III, 

### IV, orV emission standards. Once the applicable use category is determined, the engine class would be selected on the basis ofengine displacement as measured in cubic centimeters (cc). As stated in the NPRM, Class I engines are overwhelmingly found in lawnmowers. Class IIengines primarily includeengines used in generator sets, garden tractors, and commercial lawn and garden equipment. Only engines used in equipmentdefined as handheld would be allowed to meet Class 

### ill, IV, or V emission standards. Class 

### ill includes engines usedin consumer handheld products, such as small string trimmers, edgers, and brush cutters. Class IV encompasses engines used in bothresidential andcommercial settings andincludes large trimmers,

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-110­
edgers, blowers, and chain saws. Class V includes a majority ofengines utilized in commercial chain saws. This proposed engine classification approach for Phase I harmonized federal small engine regulations with California's lawn and garden regulations.



### 11.6.2 Summary ofthe Comments NAEDAobjected to the equipmentclassifications EPA used throughout the preamble, RIA and RSD.212 NAEDA's concern is that use ofthe terms "residential," "consumer," or "professional" could cause dealers to be liable in court if, for example, they sold a "professional" piece ofequipment to a residential consumerwho subsequently was injured. As an alternative, NAEDA suggested that all equipmentbeclassified using terms such as "Light Duty" or "Heavy Duty" that do not require the dealer to determine the fitness ofthe buyer to use the equipment.


### 11.6.3 EPA's Response to the Comments The Agency appreciates NAEDA's comments onequipment terminology, and recognizes the dealers' concerns about potential liability. However, it is EPA's understanding that the terms "residential," "consumer," and "professional" are the terms that have traditionally been used in the field, and therefore EPA will not change the terminology for the purposes ofthe Phase 1rule.

1 U.S. Environmental Protection Agency. "NonroadEngine and Vehicle Emission Study." EPA AirDocket#A-91-24, item ll-A-lO, November 1991. EPApublication number 21A-2001. Available from the National Technical Information Service, referenced as document PB 92­ 126960. 2 Portable PowerEquipment Manufacturers Association. ""Comments ofthe Portable Power Equipment Manufacturers Association." EPAAirDocket#A-93-25, item IV-D-22A, August 5, 1994, pp. 3-5. 3 Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPA Air Docket#A-93-25, item IV-D-27, August 5, 1994, p. 5. New York State Department ofEnvironmental Conservation. "Comments on Proposed Emission Standards for New Nonroad Spark-ignitionEngines At orBelow 19 Kilowatts." EPA AirDocket#A-93-25, item IV-D-31, August 4, 1994, p. 1. Northeast States for Coordinated Air Use Management. "Comments on Emission Standards." EPA Air Docket#A-93-25, item IV-D-23, August 5, 1994, p. 1. State and Territorial Air Pollution 

### Program Administrators and Association ofLocal Air Pollution Control Officers. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-ignition Engines At orBelow 19 Kilowatts." EPA Air Docket#A-93-25, item IV-D-08, August 4, 1994, pp. 5-7. State ofWisconsin DepartmentofNatural Resources. "Notice ofProposedRu1emaking: 

### 40 CFRPart 90, Control ofAir Pollution; Emission Standards for New Nonroad Spark-Ignited Engines At orBelow 19 Kilowatts." EPA Air Docket#A-93-25, item IV-D-18, August 3,1994, 

### p. 1. 4 Ibid.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-111­

5 Natural Resources Defense Council. "Comments," EPA AirDocket#A-93-25, item IV-D-27, August 5, 1994, p. 5. State and Territorial Air Pollution Program Administrators and Association ofLocal Air Pollution Control Officers. "Comments," EPA AirDocket #A-93-25, item IV-D-08, August 4, 1994, pp. 5-7. State ofWisconsin DepartmentofNatural Resources. "Notice," EPAAir Docket#A-93­ 25, item IV-D-18, August 3, 1994, p. 1. 6 Black& Decker Corporation. "Comments ofthe Black & Decker Corporation Concerning EPA's Proposed Rulemaking on the Control ofAir Pollution; Emission Standards for New Nonroad Spark-ignition Engines At or Below 19 Kilowatts." EPA Air Docket#A-93-25, item IVD-05, July II, 1994, pp. 2-3. State ofCalifornia Air Resources Board. "Reference no. Z-94-15." EPA Air Docket#A93-25, item IV-D-30, August 5, 1994, p. 4. State ofLouisianaDepartment ofEnvironmental Quality. "Comments." EPA Air Docket #A-93-25, item IV-D-lO, August 2, 1994, p. 1. State ofTennessee Department ofEnvironment and Conservation. "Proposed

### 40 CFR Part 90." EPA Air Docket #A-93-25, itemIV-D-04, June 29, 1994, pp. 2-3. 7 State ofCalifornia AirResources Board. "Reference," EPA AirDocket#A-93-25, item IV-D30, August 5, 1994, p. 4. 8 State ofLouisianaDepartment ofEnvironmental Quality. "Comments," EPA Air Docket#A-93­ 25, item IV-D-lO, August 2, 1994, pp. 2-3. 9 Engine Manufacturers Association and OutdoorPowerEquipment Institute. "Statement ofthe Engine Manufacturers Association and the OutdoorPowerEquipmentInstitute. It EPA AirDocket #A-93-25, item IV-D-07, August 5, 1994, pp. 13-16. Kohler Company. "Re: EPADocketNo. A-93-25." EPA AirDocket#A-93-25, itemIVD-21, August 3, 1994, p. 2. Machinery and Electrical Products, Inc. "Proposed Phase I Emissions Regulations." EPA Air Docket #A-93-25, itemIV-D-12, August 2; 1994, p. 2. Tecumseh Products Company. "EPA Phase I NPRM Comments." EPA Air Docket#A93-25, item IV-D-28, August 5, 1994, p. 1. 10 Engine Manufacturers Association and Outdoor Power Equipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp. 13-14. 11 Engine Manufacturers Association and Outdoor Power Equipment Institute. "Statement," EPA Air Docket #A-93-25, item IV-D-07, August 5, 1994, pp. 14-16. 12 ECHO. "Attn: Docket A-93-25." EPA AirDocket#A-93-25, item IV-D-32, July 6, 1994, p. 

### 2. Portable PowerEquipment Manufacturers Association. "Comments ofthe Portable Power Equipment Manufacturers Association." EPA AirDocket#A-93-25, item IV-D-22A, August 5, 1994, p. 8. 13 Portable PowerEquipment Manufacturers Association. "Comments," EPAAirDocket#A-93­ 25, item IV-D-22A, August 5, 1994, pp. 9-10. 14 Portable PowerEquipment Manufacturers Association. "Comments," EPAAirDocket#A-93­ 25, item IV-D-22A, August 5, 1994, pp. 7-9. 15 STIHL. ,.Additional Comments on the legislation for Non-Road Engines up to 19 kW (Par. 90.103)

- Effective Date." EPA Air Docket#A-93-25, item IV-D-_, September 23, 1994, pp. 1­ 

### 3. 16 Auger and PowerEquipment Manufacturers Association. "Comments on NPRM

### 40CFR Part 90." EPA Air Docket#A-93-25, item IV-D-13, August4, 1994. p. 5. 17 

### Ib.id. 18 ECHO. "Attn," EPA Air Docket#A-93-25, item' IV-D-32, July 6, 1994, p. 2.

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### 19 ECHO. "Attn," EPA Air Docket#A-93-25, item IV-D-32, July 6, 1994, p. 5. Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp. 34-35. Natural Resources Defense Council. "Comments," EPA Air Docket#A-93-25, item IV-D27, August 5, 1994, p. II. Portable PowerEquipment Manufacturers Association. "Comments," EPA Air Docket #A93-25, item IV-D-22A, August 5, 1994, p. 24. State and Territorial Air Pollution Program Administrators and Association ofLocal Air 

### Pollution Control Officers. "Comments," EPA Air Docket #A-93-25, item IV-D-08, August 4, 1994, p. 12. 20 Portable Power Equipment Manufacturers Association. "Comments," EPA Air Docket #A-93­ 25, item IV-D-22A, August 5, 1994, p.24. 21 Engine Manufacturers Association and OutdoorPowerEquipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp. 34-35. 22 Portable Power Equipment Manufacturers Association. "Comments," EPA Air Docket#A-93­ 25, item IV-D-22A, August 5, 1994, pp. 7-9. 23 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement ofthe Engine Manufacturers Association and the Outdoor Power Equipment Institute." EPA Air

### Docket #A-93-25, item IV-D-07, August 5, 1994, pp. 12-13. 24 Portable Power Equipment Manufacturers Association. "Comments ofthe Portable Power Equipment Manufacturers Association." EPA Air

### Docket #A-93-25, item IV-D-22A, August 5, 1994, p. 10. 25 Portable Power Equipment Manufacturers Association. "Comments," EPA Air

### Docket#A-93­ 25, item IV-D-22A, August 5, 1994, pp. 10-12. 26 Portable Power Equipment Manufacturers Association. "Comments," EPA Air

### Docket#A-93­ 25, item IV-D-22A, August 5, 1994, p. 12. 27 Portable Power Equipment Manufacturers Association. "Comments," EPA Air

### Docket#A-93­ 25, item IV-D-22A, August 5, 1994, pp. 12-13. 28 Portable PowerEquipment Manufacturers Association. "Comments," EPA Air Docket #A-93­ 25, item IV-D-22A, August 5, 1994, p. 13. 29 State andTerritorial Air

### Pollution Program Administrators and Association ofLocal Air 

### Pollution Control Officers. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-ignition Engines At or Below 19 Kilowatts." EPA Air Docket #A-93-25, item IV-D-08, August 4, 1994, p. 3. 30 

### State ofCalifornia Air Resources Board. "Reference no. Z-94-15." EPA Air

### Docket #A93-25, item IV-D-30, August 5, 1994, p. 3. 3 1 

### Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPA Air Docket#A-93-25, item IV-D-27, August 5, 1994, p. 8. 32 

### State andTerritorial Air Pollution Program Administrators and Association ofLocal Air 

### Pollution Control Officials. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA AirDocket#A-93-25, item IV-D-08, August 4, 1994, p. 3. 33 

### State and Territorial Air

### Pollution Program Administrators and Association ofLocal Air 

### Pollution Control Officials. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA Air 

### Docket#A-93-25, item IV-D-08, August4, 1994, p. 3. 34 

### Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPA AirDocket #A-93-25, item IV-D-27, August 5, 1994, p. 9. 35 

### State and Territorial Air

### Pollution Program Administrators and AssociationofLocal Air 

### Pollution Control Officials. "Comments onthe U.S. Environmental Protection Agency's

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### Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA Air Docket#A-93-25, item IV-D-OS, August4,1994,p. 3. 36 

### State and Territorial Air Pollution Program Administrators and Association ofLocal 

### Air Pollution Control Officials. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA Air Docket#A-93-25, item IV-D-08, August4,1994,p. 3. 37 

### Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPA Air Docket #A-93-25, itemIV-D-27, August 5, 1994, p. 9. 38 

### Machinery and Electrical Products, Inc. "Attn: Docket Number A-93-25." EPA Air Docket #A-93-25, item IV-D-12, August 2, 1994, p. 3. 39 

### Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPA Air Docket #A-93-25, item IV-D-27, August 5, 1994, p. 9. 40 

### State and Territorial 

### AirPollution Program Administrators and Association ofLocal 

### Air Pollution Control Officials. "Comments on the U.S. Environmental Protection Agency's

.Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA Air Docket #A-93-25, item IV-D-08, August 4, 1994, p. 4. 41 

### State ofCalifornia

### AirResources Board. "Reference no. Z-94-15." EPA 

### Air Docket#A93-25, item IV-D-30, August 5, 1994, p. 3. 42 

### Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPAAir Docket #A-93-25, item IV-D-27, August 5,1994,p. 9. 43 

### State and Territorial Air Pollution Program Administrators and Association ofLocal 

### Air Pollution Control Officials. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines At or Below 19 Kilowatts." EPA 

### AirDocket#A-93-25, item IV

-D-08, August4, 1994, p. 4. 44 

### Kubota Corporation. "Attention: Docket Number A-93-25." EPA AirDocket #A-93-25, item IV-D-16, August 4, 1994, p. 1. 45 

### General Equipment Company, "Attention: Docket Number A-93-25." EPA Air Docket #A93-25, item IV-D-15, August 1, 1995, p. 1.

. 46 

### Machinery and Electrical Products, Inc. "Attn: Docket Number A-93-25." EPAAirDocket #A-93-25, item IV-D-12, August 2, 1994, p. 2. 47 

### Auger and Power Equipment Manufacturers Association. "Comments on NPRM 40CFR Part 90." EPA Air Docket#A-93-25, item IV-D-13, August 4, 1994, p. 4. 48 

### Ibid. 49 

### Toro Company. "Comments," EPA Air Docket #A-93-25, item IV-D-22, received August 5, 1994, pp. 19-21. 50 

### Outdoor Power Equipment Institute. "Supplemental Comments." EPA 

### Air Docket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 6-7. 51 

### Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, pp. 23-27. 52 

### Tecumseh Products Company. "Attention: Docket Number A-93-25, EPA Phase NPRM Comments." EPA Air Docket#A-93-25, item IV-D-28, August 5, 1994, p. 2. 53 

### Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement of the Engine Manufacturers Association and the OutdoorPowerEquipment Institute." EPA 

### Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp.27-30. 54 

### Portable Power Equipment Manufacturers Association. "Comments ofthe Portable Power Equipment Manufacturers Association." EPA Air Docket#A-93-25, itemIV-D-22A, August 5, 1994, pp. 

### xx 55 

### Snapp, Lisa, U.S. Environmental Protection Agency Office ofMobile Sources, Memorandum: "Meeting with Tecumsehre; Hover Mowers and CO Standards," EPA 

### AirDocket #A-93-25, item D-IV-X, 

### December 19, 1994.

Emission Standards for New-Nonroad Spark.Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-1l4­

56 

### Portable Power Equipment Manufacturers Association. "Comments ofthe Portable Power Equipment Manufacturers Association." EPA Air Docket #A-93-25, item IV-D-22A, August 5, 1994, pp. 15-16.

. 57 

### California is preemptedby section 209 ofthe Clean 

### AirAct from imposing standards on earth augers because they are included as farm andconstruction equipment. See the following paragraph. 58 This is only a partial list ofthe equipment preemptedfrom separate regulation in California. See California Code ofRegulations, Title 13, Appendix to Section 2450 for a complete list, which is subject to revision. 59 The Agency is aware that concrete/cutoffsaws are sometimes attachedto carts for extended orheavy-duty cuts. This occasional use does not negate their overall status as handheld equipment. The Agency agrees with the comment that cutoffsaws are often used multipositionally, and thus fall into the general handheld category. Thus, the 14 kg weight limit does not apply. 60 For augers, this break point is 20 kg.
61 Lisa M. Snapp, U. S. Environmental Protection Agency Office ofMobile Sources, Memorandum: "Small Nonroad Spark-Ignition Engines

-- Determination ofHandheld Definition Weight Limit," EPA Air Docket #A-93-25, itemIV-D-X, February 17, 1995. 62 Additionally, the use oflawnmowers and, similarly, three- and four-wheeled edgers on hillsides is not considered to be muitipositional use and, hence, they do not qualify as handheld equipment. 63 

### KubotaCorporation. "Attention: Docket Number A-93-25." EPA 

### AirDocket#A-93-25, item IV-D-16, August 4, 1994, p. 1.

. 

### 64 Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statementofthe Engine Manufacturers Association and the Outdoor PowerEquipment Institute." EPA AirDocket #A-93-25, item IV-D-07, August 5, 1994, p. 32. Toro Company. "Comments ofthe Toro Company." EPA 

### AirDocket #A-93-25, itemIVD-22, received August 5, 1994, pp. 1, 

### 18-23. 65 Engine Manufacturers Association and Outdoor Power Equipment Institute. "Statement," EPA Air Docket#A-93-25, itemIV-D-07, August 5, 1994, p. 31. Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 

### 1. 66 Toro Company. "Comments," EPA Air Docket #A-93-25, item IV-D-22, received August 5, 1994, p. 3, fn. 5. 67 Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, pp. 4-6. 68 Toro Company. "Comments," EPA Air Docket #A-93-25, item IV-D-22, received August 5, 1994, pp. 4, 7-9. 69 Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, p. 4. 70 Toro Company. "Comments," EPA 

### AirDocket#A-93-25, itemIV-D-22, received August 5, 1994, pp. 4-5, 10-15. 71 Toro Company. "Comments," EPA 

### AirDocket#A-93-25, item IV-D-22, received August 5, 1994, pp. 16-18.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-115­

72 Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 16. 73 Ibid. 74 Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 17. 75 Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, pp. 18-23. 76 Dunaway & Cross. "Re: The Toro Company." EPA Air Docket#A-93-25, itemIV-D-_, November 21, 1994, p. 1. 77 North American Equipment Dealers Association. "EP A - 40CFR Part 90Emission Standards, NewNonroad SI Engines At or Below 19 KW." EPA Air Docket#A-93-25, item IV-D-02, June 15, 1994, p. 2. 78 Ibid. 79 State ofCalifornia Air Resources Board. "Reference nO.a Z-94-15." EPAAir Docket#A-93­ 25, item IV-D-30, August 5, 1994, p. 3. 80 Ibid. 81 Id. 82 Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council." EPAAir Docket#A-93-25, item IV-D-27, August 5, 1994, pp. 9-10. State and Territorial AirPollution ProgramAdministrators and Association ofLocal Air Pollution Control Officers. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on EmIssion Standards for New Nonroad Spark-ignition Engines At orBelow 19 Kilowatts." EPA Air Docket#A-93-25, item IV-D-08, August 4, 1994, p.4. 83 State and Territorial AirPollution ProgramAdministrators and Association ofLocal Air Pollution Control Officers. "Comments," EPAAir Docket#A-93-25, item IV-D-08, August 4, 1994, p. 4. 84 Ibid. 85 Id. 86 Natural Resources Defense Council. "Comments," EPA Air Docket#A-93-25, itemIV-D-27, August 5, 1994, p. 10. State and Territorial AirPollution ProgramAdministrators and Association ofLocal Air Pollution Control Officers. "Comments," EPA AirDocket#A-93-25, item IV-D-08, August 4, 1994, pp. 4-5. 87 Ibid. 88 State andTerritorial AirPollution ProgramAdministrators and Association ofLocal Air Pollution Control Officers. "Comments," EPAAirDocket#A-93-25, item IV-D-08, August 4, 1994, p. 5. 89 Ibid. 90 Dunaway & Cross. "Re: The Toro Company," EPA Air Docket#A-93-25, itemIV-D-_, November 21, 1994. Toro Company. "Comments," EPA AirDocket#A-93-25, item IV-D-22, received August 5, 1994. 91 Dunaway & Cross. liRe: TheToro Company," EPA Air Docket#A-93-25, itemIV-D-_, November 21, 1994, p. 2. Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 4. 92 Toro Company. "Comments," EPA Air Docket #A-93-25, item IV-D-22, received August 5, 1994, pp. 2-3.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-1l6­



### 93 Dunaway & 

### Cross. "Re: The Toro Company," EPA Air Docket#A-93-25, item IV-D-_, November 21, 1994, p. 4. 94 Dunaway & 

### Cross. "Re: The ToroCompany," EPA Air Docket #A-93-25, item IV-D-_, November 21, 1994, p. 10. 95 Ibid. 96 Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, pp. 9-10. 97 Ibid. 98 Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, pp. 10, 18, 20. 99 Toro Company. "Comments," EPA 

### AirDocket #A-93-25, item IV-D-22, received August 5, 1994, p. 10. 100 Dunaway & 

### Cross. "Re: The Toro Company," EPA 

### Air Docket#A-93-25, item IV-D-_, November 21, 1994, p. 12, fn. 6. 101 

### Toro Company. "Comments," EPA 

### AirDocket#A-93-25, item IV-D-22, received August 5, 1994, p. 27. 102 

### Engine Manufacturers Association and Outdoor PowerEquipmentInstitute. "Statement ofthe Engine Manufacturers Association and the Outdoor PowerEquipment Institute." EPA 

### AirDocket #A-93-25, item IV-D-07, August 5, 1994, p. 27. OutdoorPowerEquipment Institute. "Supplemental Comments." EPA Air Docket#A-93­ 25, item IV-D-20, August 5, 1994, p. 6. Tecumseh Products Company. "EPA Phase I NPRM Comments." EPA 

### AirDocket#A93-25, item IV-D-28, August 5, 1994, p. 2. Toro Company. "Comments ofthe Toro Company." EPA 

### AirDocket #A-93-25, itemIVD-22, received August 5, 1994, p. 23.

103 

### Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 27. 104 

### Toro Company. "Comments," EPA Air Docket #A-93-25, item IV-D-22, received August 5, 1994, p. 23. 105 

### Tecumseh Products Company. "EPA Phase I," EPA Air Docket #A-93-25, item IV-D-28, August 5, 1994, p. 2. 106 

### U.S. Environmental Protection Agency. "Nonroad Engine and Vehicle Emission Study." EPA Air Docket#A-91-24, item II-A-lO, November 1991. EPA publication number 21A-2001. Available from the National Technical Information Service, referenced as document 

### PB 92­ 126960. 107 Engine Manufacturers Association and Outdoor Power Equipment Institute. "Statement," EPA Air Docket #A-93-25, item IV-D-07, August 5, 1994, p. 27. Outdoor Power Equipment Institute. "Supplemental Comments," EPA 

### AirDocket#A-93­ 25, item IV-D-20, August 5, 1994, p. 6. Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 25. 108 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA AirDocket#A-93-25, item IV-D-07, August 5, 1994, pp. 28-29. OutdoorPowerEquipment Institute. "Supplemental Comments'" EPA 

### AirDocket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 6-7. Toro Company. "Comments," EPA 

### AirDocket#A-93-25, item IV-D-22, received August 5, 1994, pp. 25-27. 109 

### Il:!iQ.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-117­



### 110 Engine Manufacturers Association and Outdoor Power Equipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5,1994, pp. 29-30. OutdoorPower Equipment Institute. "Supplemental Comments," EPA Air

### Docket #A-93­ 25, item IV-D-20, 

### August 5, 1994, p. 6. Toro Company. "Comments," EPA Air Docket#A-93-25, item IV-D-22, received August 5, 1994, pp. 28-29. III Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 29. OutdoorPowerEquipment Institute. "Supplemental Comments," EPAAir Docket#A-93­ 25, item IV-D-20, August 5, 1994, p. 6. Toro Company. "Comments," EPA Air 

### Docket#A-93-25, item IV-D-22, received August 5, 1994, p. 28. 112 Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statement," EPA Air Docket #A-93-25, item IV-D-07, August 5, 1994, pp. 30-31. OutdoorPower Equipment Institute. "Supplemental Comments," EPA AirDocket#A-93­ 25, item IV-D-25, August 5, 1994, p. 7. Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 29. 113 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA Air Docket #A-93-25, item IV-D-07, August 5, 1994, p. 29. Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 28. 114 Ibid. 115 Toro Company. "Comments," EPA Air Docket#A-93-25, itemIV-D-22, received August 5, 1994, p. 29. 116 Ibid. 117 Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council. II 

### EPA Air Docket#A-93-25, item IV-D-27, August 5, 1994, p. 9. State and Territorial Air

### Pollution ProgramAdministrators and Association ofLocal Air 

### Pollution Control Officers. "Comments on the 

### V.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-ignition Engines At or Below 19 Kilowatts." EPA Air Docket #A-93-25, item IV-D-08, August4, 1994, p. 4. 118 Ibid. 119 Id. 120 OutdoorPower Equipment Institute. "Supplemental Comments," EPA Air 

### Docket#A-93-25, item IV-D-20, August 5, 1994, attachment entitled Single-stage Snowthrowers. 121 Power Systems Research,.Engindata North America and Parts Link 

### Aftermarket, 1992, St. Paul-Minneapolis, Minnesota, EPA Air Docket#A-93-25, item#II-K-15.
122 Drachand, Don, California Air Resources Board. Letterto Richard Wilson, 

### V.S. Environmental Protection Agency, EPA Air Docket#A-93-25, item#IV-D-30, August 5, 1994, p. 1. 

### 123 59 FR 55930.
124 Portable Power EquipmentManufacturers Association. "Comments ofthe Portable Power Equipment Manufacturers Association." EPA Air Docket#A-93-25, itemIV-D-22A, 

### August 5, 1994, pp. 16-17. 125 PortablePowerEquipmentManufacturers Association. "CommentS," EPA Air 

### Docket#A-93­ 25, itemIV-D-22A, August 5, 1994, pp. 10-13.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95ll8­

Toro Company. "Comments ofthe Toro Company." EPA Air Docket#A-93-25, item IVD-22, received August 5, 1994, pp. 5-6. 126 Natural Resources Defense CounciL "Comments ofthe Natural Resources Defense Council." EPA Air Docket #A-93-25, item IV-D-27, August 5, 1994, p. 10. State andTerritorial 

### Air Pollution Program Administrators andAssociation ofLocal 

### Air Pollution Control Officers. "Comments on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-ignition Engines At orBelow 19

. Kilowatts." EPA Air Docket #A-93-25, item IV-D-08, August4, 1994, p. 5. State ofCaliforniaAirResources Board. "Reference no. Z-94-15." EPA Air Docket#A93-25, item IV-D-30, August 5, 1994, p.5. 127 Engine Manufacturers Association and OutdoorPowerEquipmentManufacturers Institute. "Statement ofthe Engine Manufacturers Association and the Outdoor PowerEquipmentInstitute." EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp. 16. OutdoorPowerEquipment Institute. "Supplemental Comments." EPA 

### Air Docket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 1-4.

. 128 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 17. OutdoorPowerEquipment Institute. "Supplemental Comments," EPA Air Docket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 4-5. 129 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 16. 130 General Equipment Company. "Comments to the Docket Proposal." EPA AirDocket#A-93­ 25, item IV-D-15, August 1, 1994,p. 1. 131 Engine Manufacturers Association and OutdoorPowerEquipmentInstitute. "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 37. OutdoorPowerEquipment Institute. "Supplemental Comments," EPA 

### Air Docket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 7-8. 132 Tecumseh Products Company. "EPA Phase I NPRM Comments." EPA AirDocket#A-93­ 25, item IV-D-28, August 5, 1994, p. 3. 133 ECHO. "Attn: Docket A-93-25." EPA Air Docket #A-93-25, itemIV-D-32, July 6, 1994, p.2. Engine Manufacturers Association and Outdoor PowerEquipment Institute, "Statement," EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, p. 17. Onan Corporation. "Attention: Docket A-93-25." EPA AirDocket#A-93-25, itemIV-D34, August 4, 1994, pp. 4-5. OutdoorPowerEquipment Institute. "Supplemental Comments," EPAAirDocket #A-93­ 25, item IV-D-20, August 5, 1994, pp. 1-6. Tecumseh Products Company. "EPA Phase I," EPA Air Docket#A-93-25, item IV-D-28, August 5, 1994, p. 2.

. 134 Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement," EPA AirDocket#A-93-25, itemIV-D-07, August 5, 1994, p. 17. 135 State ofTennessee Department ofEnvironment and Conservation. "Proposed40CPRPart 90." EPA AirDocket#A-93-25, item IV-D-04, June 29, 1994, p. 1. 136 Auger and PowerEquipmentManufacturers Association. "Comments onNPRM40CPRPart 90." EPAAir Docket#A-93-25, itemIV-D-13, August 4, 1994, p. 5. 137 Machinery and Electrical Products, Inc. "Proposed PhaseaI Emissions Regulations." EPA Air Docket#A-93-25, item IV-D-12, August 2, 1994, p. 2. 138 Natural Resources Defense Council. "Comments," EPA AirDocket#A-93-25, item IV-D27, August 5, 1994, p. 10.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95119­



### State and Territorial Air Pollution Program Administrators and Association ofLocal 

### Air Pollution Control Officers. "Comments," EPA Air Docket #A-93-25, itemIV-D-08, August 4, 1994, p. 5. 139 Tecumseh Products Company. "EPA Phase I," EPA Air Docket#A-93-25. item IV-D-28, August 5. 1994, p. 3. 140 North American Equipment Dealers Association. "EPA

- 40CFR Part 90Emission Standards, New Nonroad SI Engines At or Below 19 KW. EPA Air Docket #A-93-25, itemIVD-02, June 15, 1994, p. 2. 141 

### Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement of the Engine Manufacturers Association and the Outdoor Power Equipment Institute." EPA Air Docket #A-93-25, item IV-D-07, August 5, 1994. pp.32-33. 142 

### Kohler Co. "Re: EPA Docket No. A-93-25," EPA 

### AirDocket #A-93-25, item IV-D-21, August 3, 1994, pp. 3-4. 143 

### Tecumseh Products Company. "EPA Phase I," EPA Air 

### Docket#A-93-25. itemIV-D-28, August 5, 1994,p. 3 144 

### Onan Corporation. "Comments." EPA Air Docket#A-93-25. item IV-D-34, pp. 3-4. 145 

### Onan, Kohler, EMA and OPEl. 146 

### Kohler, OPEl 147 

### EMA and OPEl, Tecumseh 148 

### Letter to Debbie Wood, U.S.Environmental Protection Agency, from Engine Manufacturers Association, 11129194. 

### 149 Thrift, Michael, U.S. Environmental Protection Agency Office ofGeneral Counsel, Memorandum oftelephone conversation with Ralph Hovnanian, EPA 

### AirDocket#A-93-25, item IV-D-19, November 5, 1994.

. 150 Public Law 95-574, October 27, 1992, as amendedby Public law 95-609, November 8 1978. 151 ECHO. "Attn: Docket A-93-25." EPA Air 

### Docket#A-93-25, item IV-D-32, July 6, 1994,

# ~5i' Some ofthe most common-used standards include ANSI B71.5 (a voluntary US standard, with a measurement andrating procedure, adhered to by OPEl members), EEC Council Directive 841538IEEC 

### (an EEC regulation dealing with permissible soundpower levels oflawnmowers), ISO 11094 (an international standardrelating to mowing equipment).

153 

### ECHO. "Attn: Docket A-93-25." EPA Air 

### Docket #A-93-25, item IV-D-32, July 6, 1994, p. 

### xx. 154 Portable Power Equipment Manufacturers Association. 

### "Comments," EPA Air Docket #A-93-25, item IV-D-22A, August 5, 1994, pp. 35-36. 155 Portable PowerEquipment Manufacturers Association. 

### "Comments," EPA Air Docket #A-93-25, item #IV-D-22A, August 5, 1994, pp. 

### xx.

156Portable Power Equipment Manufacturers Association. "Comments," EPAAir

### Docket #A-93­ 25, item IV-D-22 (part 2 of2), August 5, 1994, p.26. 157Kohler Co. "Re: EPA Docket No. A-93-25," EPAAir 

### Docket #A-93-25, itemIV-D-21, August 3, 1994, p.4. 1580nan Corporation. "Comments," EPAAir 

### Docket #A-93-25, item IV-D-34, August 4, 1994, p.26; Engine Manufacturers Association and OutdoorPowerEquipment Institute. "Statement of

Emission Standards for New-Nonroad Spark·lgnition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-120­

the Engine Manufacturers Association and The OutdoorPowerEquipment Institute," EPA Air Docket#A-93-25, itemIV-D-07, August 5, 1994, p.50. 1590nanCorporation. "Comments," EPA Air Docket#A-93-25; item IV-D-34. August 4, 1994, p.5. 16DNatural Resources Defense Council. "Comments," EPA AirDocket#A-93-25, itemIV-D-27. August 5, 1994, p.1l. 161EngineManufacturers Association and OutdoorPowerEquipment Institute. "Statement ofthe Engine Manufacturers Association andThe OutdoorPowerEquipment Institute," EPAAirDocket #A-93-25, item IV-D-07, August 5, 1994, p.43. 1620nan Corporation. "Comments," EPA AirDocket#A-93-25, item IV-D-34, August 4, 1994, p.28 163EngineManufacturers Association and OutdoorPower Equipment Institute. "Statement ofthe Engine Manufacturers Association andThe OutdoorPowerEquipment Institute," EPA AirDocket #A-93-25, item IV-D-07, August 5, 1994, p.45 164Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statement ofthe Engine Manufacturers Association and The OutdoorPowerEquipment Institute," EPAAirDocket #A-93-25, item IV-D-07, August 5, 1994, p.46 165Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement ofthe Engine Manufacturers Association and The OutdoorPowerEquipmentInstitute," EPAAirDocket #A-93-25, item IV-D-07, August 5, 1994, p.46?; Onan Corporation. "Comments," EPA Air Docket#A-93-25, item IV-D-34, August 4, 1994, p.26 166Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement ofthe Engine Manufacturers Association and The Outdoor Power Equipment Institute," EPAAir Docket #A-93-25, itemIV-D-07, August 5, 1994, p.46?; Onan Corporation. "Comments," EPAAir Docket #A-93-25, item IV-D-34, August 4, 1994, p.26 167Portable PowerEquipmentManufacturers Association. "Comments," EPAAir Docket#A-93­ 25, itemIV-D-22 (part 2 of2), August 5, 1994, p.26 168Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement ofthe Engine Manufacturers Association and The OutdoorPowerEquipment Institute," EPA AirDocket #A-93-25, item IV-D-07, August 5,1994, p.4S. 169Engine Manufacturers Association and OutdoorPowerEquipment Institute. "Statementofthe Engine Manufacturers Association and The OutdoorPowerEquipment Institute," EPAAir Docket #A-93-25, item IV-D-07, August 5, 1994, pp.?? 1700nan Corporation. "Comments," EPA Air Docket#A-93-25, item IV-D-34, August4, 1994, p.26 171HondaMotorCo., Ltd. "Comments," EPA AirDocket#A-93-25, item IV-D-25, August 5, 1994, p.l. 172Engine Manufacturers Association and Outdoor PowerEquipment Institute. "Statement ofthe EngineManufacturers Association andThe OutdoorPowerEquipment Institute," EPAAir Docket. #A-93-25, itemIV-D-07, August 5, 1994, p.49 173Engine Manufacturers Association and OutdoorPower Equipment Institute. "Statementofthe Engine Manufacturers Association andThe OutdoorPowerEquipment Institute," EPA AirDocket #A-93-25, item IV-D-07, August 5,1994, p.?? 1740nanCorporation. "Comments," EPA Air Docket #A-93-25, item IV-D-34, August4, 1994, p.25. 1750nanCorporation. "Comments," EPA Air Docket #A-93-25, itemIV-D-34, August4, 1994, p.27. 1760nanCorporation. "Comments," EPA Air Docket#A-93-25, item IV-D-34, August4,1994, p.27.

Emission Standards for New-Nonroad Spark.-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5127/95-121­

177Portable Power Equipment Manufacturers Association. "Comments," EPA AirDocket#A-93­ 25, item IV-D-22 (part 2 of2), August 5, 1994, p.xx 178North American Equipment Dealers Association. "Comments," EPA AirDocket#A-93-25, item IV-D-02, June 15, 1994, p.5. 179 NaturalResources Defense Council, "Comments ofthe Natural Resource Defense Council Regarding Proposed Emission Standards for New Nonroad Spark Ignition Engines at orbelow 19 Kilowatts." EPA Air Docket A-93-25, item IV-D-27, August 5, 1994, p. 8. 180 Id. at p. 8. 181 NRDC, item IV-D-27, STAPP

### N ALAPCO, "Comments ofthe

... on the U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark­ Ignition Engines AtorBelow 19 Kilowatts." EPAAirDocket A-93-25, item IV-D-08, August4, 1994, p. 9-10. 182 Tecumseh Products Company, "EPA Phase 1NPRM Comments." EPA Air DocketA-93-25, item IV-D-28, August 5, 1994, p. 2-3. 183 Portable PowerEquipmentManufacturers Association, "Comments ofthe Portable Power Equipment Manufacturers Association." EPA Air Docket A-93-25, item IV-D-22, August 5, 1994,p.30 184 STAPPA?ALAPCO at p. 10. 185 Kohler, Letter to DocketClerk. EPA Air DocketA-93-25, item IV-D-21, August 3, 1995, p. 3. Engine Manufacturers Association, "Statement ofthe Engine Manufacturers Association and the Outdoor PowerEquipment Institute." EPA Air Docket A-93-25, item xxx, August 5, 1994, p. 51. 186Id.

. 187 EMA at p. 52 188 PPEMA, andEMA. 189 City ofChicago. "RE: Proposed Rules for Emission Standards for New Nonroad Spark- Ignition Engines at orBelow 19 Kilowatts

- 59 Fed. Reg. 25399." EPA Air Docket#A-93-25, item IV-D-26, July 19, 1994, pp. 1-2. 190 Portable Power Equipment Manufacturers Association. "Comments ofthe Portable Power EquipmentManufacturers Association." EPA AirDocket#A-93-25, item IV-D-22A, August 5, 1994, pp. 48-51. 191 Outdoor PowerEquipment Institute. "Supplemental Comments," EPAAirDocket#A-93­ 25, item IV-D-20, August 5, 1994, pp. 5-8. 192 Onan Corporation. "Comments," EPA Air Docket#A-93-25, itemIV-D-34, p. 6. 193 Engine Manufacturers Association and Outdoor PowerEquipmentInstitute. "Statement of the Engine Manufacturers Association and the OutdoorPowerEquipment Institute." EPA Air Docket#A-93-25, item IV-D-07, August 5, 1994, pp.63-64. 194 North American Equipment Dealers Association. "EPA

-- 40CFRPart

### 90 Emission Standards, New Nonroad SIEngines At orBelow 19 KW." EPA AirDocket#A-93-25, item IV­ D-02, June 15, 1994, p. 3. 195 Tecumseh Products Company. "EPAPhase I," EPAAirDocket#A-93-25, item IV-D-28, August 5, 1994, p. 3. 196 ECHO. "Attn: DocketA-93-25." EPA AirDocket#A-93-25, item IV-D-32, July 6,1994,**p~.** 5-6. 1 7 Formore discussion on the impact on small entities, see section VII. C. ofthe preamble, "Impacton SmallEntities;" see also the corresponding section in the preambleto the NPRM at 59 FR 25399, 25430 (May 16, 1994). 198 Engine Manufacturers Association/Outdoor Power EquipmentInstitute. "Statementofthe Engine Manufacturers Association and the Outdoor PowerEquipmentInstitute," EPA AirDocket #A-93-25, item #IV-D-07, August 4, 1994, pp. 61-63.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95-122­



### 199 Portable PowerEquipment Manufacturers Association. 

### "Comments," EPA AirDocket #A-93-25, item#IV-D-22A, August 5, 1994, pp. 22-24. 200 59 FR 31306 (June 17, 1994). 201 Briggs & 

### Stratton Corporation. liRe: Docket No. A-93-25," letter and attachment. EPA Air Docket#A-93-25, item# IV-D-33, August 18, 1994. 202 Manufacturers ofEmission Controls Association. liRe: Emission Standards for New Nonroad Spark-Ignition Engines at orbelow 19 Kilowatts, Docket No. A-93-25," letter and attachment. EPA Air Docket#A-93-25, item# IV-D-29, June 21, 1994, pp. 3-4. 203 Drachand, Don, CaliforniaAirResources Board. Letterto Richard Wilson, U.S. Environmental Protection Agency, EPA Air 

### Docket #A-93-25, item#IV-D-30, August 5, 1994, p. 

### 5. 204 STAPPAlALAPCO. "Comments ofthe State and Territorial Air 

### Pollution Program Administrators and the Association ofLocal Air 

### Pollution Control Officers onthe U.S. Environmental Protection Agency's Proposed Rulemaking on Emission Standards for New Nonroad Spark-Ignition Engines at orbelow 19 Kilowatts," EPA Air 

### Docket#A-93-25, item#IV­ D-08, August 4, 1994, pp. 10-11. 205 Natural Resources Defense Council. "Comments ofthe Natural Resources Defense Council," EPA Air Docket #A-93-25, item #IV-D-27, August 5, 1994, pp. 6-8. 206 Natural Resources Defense CounciL "Comments ofthe Natural Resources Defense Council," EPA Air Docket #A-93-25. item #IV-D-27, August 5, 1994, p. 7. 207 Portable Power Equipment Manufacturers Association. 

### "Comments," EPA Air Docket #A-93-25, item #IV-D-22A, August 5, 1994, p. 

### xx. 208Holliday Environmental Services. Written submission to EPA Air Docket#A-93-25, item IV­ D-Ol 209NRDC, 8/25/94, 

### Docket No. A-93-25, IV-D-27, p.xx. 21ONorth American Equipment Dealers Association. Written submission to EPA Air 

### Docket A-91­ 21, item II-D-02, December 10, 1991, p.2. 2l I

### North American Equipment**De~ers** 

### Association. Written submission to EPA Air 

### Docket A-91­ 21, item II-D-02, December 10, 1991, p. 2l2North American Equipment Dealers Association. Written submission to EPA Air 

### Docket A-91­ 21, item II-D-02, December 10, 1991, pp.l. 10.

Emission Standards for New-Nonroad Spark-Ignition Engines at or Below 19 Kilowatts: Response to Comments on the NPRM 5/27/95