# Standards for Emissions From Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Motor Vehicles and Motor Vehicle Engines, and Certification Procedures for Aftermarket Conversions; Final Rule ENVIRONMENTAL PROTECTION AGENCY > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A94-22131 ## Record - **Collection:** Federal Register - **Document type:** Uncategorized Document - **Published:** September 21, 1994 ## Text SUMMARY: Today's rule provides emission standards and test procedures for the certification of new natural gas-fueled, and liquefied petroleum gas-fueled light-duty vehicles, light-duty trucks, heavy-duty engines and vehicles, and motorcycles. The regulations are effective with the 1997 model year, although optional certification prior to the 1997 model year will be available. Today's rule also provides fuel economy test procedures and calculation equations for natural gas- fueled light-duty vehicles and trucks, effective upon publication, to allow these vehicles to be included in a manufacturer's corporate average fuel economy (CAFE). Finally, today's rule provides procedures for the certification of aftermarket conversion equipment to allow a vehicle or engine to operate completely or in part on a fuel other than the fuel for which it was originally designed and manufactured. This action is being taken in order to remove the possibility that the absence of such standards could hinder the development of natural gas and liquefied petroleum gas as transportation fuels. These standards are intended to provide a comparable degree of environmental protection to that afforded by the standards applicable to gasoline, diesel and methanol vehicles, and to ensure that aftermarket conversions do not degrade the emissions performance of the vehicles or engines being converted. DATES: Except as specified elsewhere in this DATES section, this final rule is effective September 21, 1994. The effective date of Secs. 80.32, 80.33, 86.001-9(d)(1)(iv), 86.001-28(h), 86.004-9(d)(1)(iv), 86.004-28(h), 86.098-8(d)(1)(iv), 86.098-28(h), 86.099-8(d)(1)(iv), 86.150-98(d) and 86.157-98 is November 21, 1994, unless notice is received by October 21, 1994 that interested parties wish to submit adverse or critical comments on these sections. If the effective date is changed, timely notice will be published in the Federal Register. The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of September 21, 1994, except as specified elsewhere in this DATES section. 40 CFR 85.503, 85.505, 86.542-90, 86.094-23, 86.095-24, 86.095-35, 86.1242-90, 86.098-28, 86.113-94, 86.1344-94, 86.142-90, 86.150-98, 86.513-94 and 600.113-93 are not effective until the Office of Management and Budget (OMB) has approved the information collection requirements contained in them. A document will be published in the Federal Register when OMB has approved the information collection requirements. ADDRESSES: Written comments on those sections effective November 21, 1994 should be submitted both to the contact person for this rule (see For Further Information Contact) and to the docket for this rulemaking at the following address. Materials relevant to this rule have been placed in Docket No. A-92-14 by EPA. The docket is located at: Air Docket Section, U.S. Environmental Protection Agency, 401 M Street, SW., Washington, DC 20460 in room M-1500, Waterside Mall (ground floor), and may be inspected between 8 a.m. and 4 p.m. on weekdays. EPA may charge a reasonable fee for copying docket materials. In addition, copies of the Summary and Analysis of Comments document, which develops certain issues relevant to this final rulemaking, may be obtained by request from the contact person below. This document contains the Agency's response to the public comments received in regard to the Notice of Proposed Rulemaking (NPRM). FOR FURTHER INFORMATION CONTACT: Mr. John Mueller, Regulation Development and Support Division, U.S. Environmental Protection Agency, 2565 Plymouth Road, Ann Arbor, Michigan 48105: phone (313) 668-4275. To obtain copies of this final rule or the Summary and Analysis of Comments document please contact Ms. Donna Hoover at (313) 668-4278 or at the above address. SUPPLEMENTARY INFORMATION: Table of Contents I. Introduction II. Description of Action A. Timing B. New Vehicle Standards C. Certification Test Fuel Specification D. Test Procedures E. Fuel Economy F. Aftermarket Conversions G. Fees III. Public Participation A. Timing of Requirements B. Standards for HC 1. NMHC vs. THC Standards 2. Heavy-Duty NMHC Standards 3. Evaporative Emission Standards C. Refueling Emission Standards 1. Natural Gas 2. LPG Vehicle/Pump Interface 3. LPG Tank Venting D. Standards for CO and Crankcase Emissions 1. Idle CO 2. Crankcase Emissions E. On-Board Diagnostics F. HC Measurement G. Fuel Composition H. Fuel Economy I. Aftermarket Conversions 1. Applicability 2. Test Procedures 3. On-board Diagnostics 4. Liability IV. Environmental Effects V. Economic Impacts VI. Statutory Authority VII. Executive Order 12866 VIII. Reporting and Recordkeeping Requirements IX. Impact on Small Entities X. Judicial Review I. Introduction Recently there has been increasing interest in the use of non- petroleum transportation fuels for a variety of reasons, including the potential environmental benefits offered by these fuels. Natural gas and liquefied petroleum gas (LPG) are among the more prominent of these fuels, along with methanol and ethanol. EPA promulgated emission standards for methanol-fueled vehicles on April 11, 1989 (54 FR 14426) due to the imminent commercialization of those vehicles. However, there are currently no emission standards in place for vehicles which operate, all or in part, on natural gas and LPG. This lack of standards is seen as a potential barrier to the widespread commercial introduction of these vehicles into the marketplace due to the uncertainties the manufacturers face regarding potential future standards where EPA has not yet addressed any of the issues involved. In addition, the recent rise in interest in these fuels has resulted in increased interest in aftermarket conversions (i.e., the conversion of a vehicle or engine to operate on a fuel other than that for which it was originally designed and certified to operate). Again, the lack of defined certification procedures for conversions, as well as the absence of a method to demonstrate good emissions performance of such conversions, are seen as potential barriers to their more widespread use for two reasons. First, the lack of defined certification procedures leads to uncertainty among converters as to whether the conversions they perform constitute tampering and result in the potential associated liability. Second, the potential for environmental benefits associated with gaseous fuels has led to increased interest in marketing conversions as an environmental strategy. The lack of a recognized procedure for confirming emissions performance has been seen as hindering efforts to market conversions in this manner. Thus, in order to remove these potential barriers EPA published a Notice of Proposed Rulemaking (NPRM) proposing emission standards for natural gas and LPG vehicles, and certification procedures for aftermarket conversions on November 5, 1992 (57 FR 52912). A public hearing was held on December 3, 1992, in Ann Arbor, Michigan at which verbal comments on the NPRM were received. Written comments responding to the proposal were also received from 34 public and private parties. The Agency fully considered all comments received in developing today's final rule. The remaining sections of this preamble describe EPA's resolution of the issues associated with the rulemaking. Section II describes today's action and summarizes the new requirements. Section III reviews the major comments received on the NPRM and the Agency's analysis of those comments. Subsequent sections summarize the technical feasibility, leadtime requirements, environmental effects, and economic effects associated with today's action. II. Description of Action This section describes each provision of today's rule. In general, today's rule extends the coverage of the existing federal motor vehicle emissions program to include natural gas and LPG vehicles (hereinafter referred to as gaseous-fueled vehicles). As such, EPA's current regulations governing certification, production line, and in-use requirements are for the most part adopted for gaseous-fueled vehicles. Rather than present an exhaustive review of the entire federal emissions program, this section contains a basic description of the gaseous-fueled vehicle regulations and highlights where these regulations differ from those currently in place for other vehicles. For additional information on the new or existing program requirements the reader is referred to the accompanying regulations appearing at the end of today's notice, and Title 40, parts 80, 85, 86, 88 and 600 of the Code of Federal Regulations, which this rulemaking amends. A. Timing EPA proposed that these standards be effective with the 1994 model year, and explained that the Agency did not expect that significant lead-time for developing emission control technology would be required for compliance. Nonetheless, because this rule is not being promulgated until after the start of the 1994 model year, EPA no longer believes that there is sufficient time to certify vehicles and engines pursuant to these regulations for the 1994 model year. Further, EPA received several comments stating that leadtime was required for technology development, especially for durability demonstration, in addition to that required for the certification process alone. Therefore, EPA is promulgating the standards to be effective with the 1997 model year. Finally, the refueling requirements for gaseous-fueled vehicles will be implemented consistent with the recently finalized refueling emission standards for other vehicles (three year phase-in beginning with the 1998 model year for light-duty vehicles and the 2001 model year for light-duty trucks).\1\ The requirements for refueling stations will take effect on January 1, 1998 for large volume stations, with a two year delay until January 1, 2000 for those stations which dispense less than 10,000 gallons per month on a gasoline equivalent basis. This phase in for smaller stations is consistent with the approach taken with the dispensing rate limits placed on gasoline refueling stations contained in the evaporative emissions final rule.\2\ --------------------------------------------------------------------------- \1\59 FR 16262, April 6, 1994. \2\58 FR 16002, March 24, 1993. --------------------------------------------------------------------------- EPA proposed that manufacturers be allowed to certify engines and vehicles produced prior to the effective model year in order to include engines in the emissions trading and banking program, and to include vehicles in manufacturers' corporate average fuel economy. EPA received no adverse comments on this aspect of the proposal. For this reason, manufacturers may choose to comply prior to the 1997 model year, including the 1994 model year. Including 1994 model year engines in the emissions trading and banking program and raises an issue whether engines manufactured in model year 1994 prior to the promulgation of this rule may be included in the program. A similar situation was confronted in the original banking and trading rule. There, EPA allowed banking for the full 1990 model year, even though the rule was promulgated on July 26, 1990. See 55 FR 30584, 30587. In that case, EPA placed certain restrictions on the inclusion of 1990 model year engines, to ensure credits were only given for significant reductions below the 1990 standards. This was to ensure that ``windfall'' credits from exceeding the arguably ``lax'' pre-1991 standards would not be used in the transition to the more stringent 1991 standards. As a result, if no restrictions on trading and banking were imposed, then the engines that had always exceeded the 1990 standards would for the first time be able to use the extra reductions as ``windfall'' credits to offset engines that did not yet meet the new and more stringent 1991 standards. See 55 FR at 30597. EPA does not believe such restrictions are necessary in this case. Since 1991, engines using other fuels, such as methanol, have been able to generate credits to offset higher emitting engines. EPA believes that gaseous-fueled engines should have an equal opportunity to use such credits as gasoline-, diesel-, and methanol-fueled engines, now that emissions standards and test procedures are in place in time for the 1994 model year. As EPA explained in the response to comments in the trading and banking final rule, CNG engines were not included at that time due to the absence of standards, test procedures, and certification protocols. See id at 30609. Now that these rules are in place, there is no longer any reason to disadvantage CNG engines vis a vis other fuels. In addition, EPA does not believe that the credits manufacturers might obtain from gaseous-fueled engines are ``windfall,'' since they arguably would not have manufactured such engines in model year 1994 but for EPA's actions to provide an incentive to do so. Rather, EPA believes manufacturers had an incentive to manufacture gaseous-fueled engines based on EPA actions prior to this final rule. EPA proposed these standards in November 1992, and began developing these standards substantially before that. EPA believes this overall incentive further supports allowing manufacturers to include all 1994 model year engines in the trading and banking program. The aftermarket conversion certification procedures contained in today's rule are available to converters as a way of obtaining an exemption from the tampering prohibition. Since this procedure creates an exemption and is optional it will be available upon publication in the Federal Register. EPA's current policy toward conversions will continue to apply to aftermarket conversions which have not received an exemption under this new program.\3\ --------------------------------------------------------------------------- \3\See March 4, 1993 Fact Sheet available in the public docket. --------------------------------------------------------------------------- The Administrative Procedure Act requires 30 days notice before a rule may become effective, except under certain circumstances such as when the rule recognizes an exemption or when the Agency can demonstrate good cause for immediate effect. The Agency believes it has good cause for this rule to take immediate effect in the case of the new vehicle standards since compliance with the new vehicle standards is optional until well after the 30 day period. In the case of aftermarket conversions, because this rule creates an exemption from the tampering prohibition under section 203 of the Act it does not require 30 days notice, and this exemption will be available upon publication in the Federal Register. B. New Vehicle Standards The new gaseous-fueled vehicle and engine emission standards contained in today's notice are effective with the 1997 model year. Optional compliance prior to the 1997 model year is available to manufacturers who wish to include their vehicles and engines in emissions averaging, trading and banking programs, as well as the CAFE program in the case of natural gas-fueled vehicles. In general, the Agency seeks to control vehicles operated on alternative fuels so that their emissions are no greater than their petroleum-fueled counterparts. Thus, the exhaust emission standards for gaseous-fueled vehicles are numerically equivalent to those which apply to other, currently regulated vehicles and engines. The only significant departure from this approach is in the area of hydrocarbon (HC) standards for natural gas fueled vehicles and engines. Prior to the 1994 model year, regulated vehicles (i.e., gasoline, petroleum diesel and methanol) are only required to meet total hydrocarbon (THC) standards. However, beginning with the 1994 model year, currently regulated light-duty vehicles and light-duty trucks will also be required to meet separate nonmethane hydrocarbon (NMHC) standards as part of the Tier 1 requirements of the Clean Air Act.\4\ For natural gas-fueled light-duty vehicles and light-duty trucks only the NMHC standards will apply. In the case of natural gas-fueled heavy-duty engines, NMHC standards which provide the same degree of NMHC control as the current THC standards provide for petroleum-fueled vehicles will apply. In the case of LPG vehicles and engines, the HC standards are the same as those for currently regulated vehicles. A summary of today's gaseous-fueled vehicle emission standards is contained in Tables 1 through 4. --------------------------------------------------------------------------- \4\The Agency uses the phrase ``Tier 1'' to denote the 1994 and later model year standards in part because they are nearly identical to the Tier 1 standards prescribed by section 202(g) of the Clean Air Act for petroleum-fueled vehicles (56 FR 25724, June 5, 1991). Use of this phrase is not meant to suggest that gaseous-fueled vehicles are subject to the section 202(g) Tier 1 standards. Table 1.--Emission Standards for 1997 and Later Model Year Gaseous-Fueled Light-Duty Vehicles (q/mi)1 ---------------------------------------------------------------------------------------------------------------- Evaporative Fuel Standards\2\ THC NMHC CO NOX PM\3\ hydrocarbons (g/test) ---------------------------------------------------------------------------------------------------------------- Intermediate Useful Life Standards\4\ ---------------------------------------------------------------------------------------------------------------- Natural Gas............ Tier 0............ ......... 0.34 3.4 1.0 0.20 2.0 Natural Gas............ Tier 1............ ......... 0.25 3.4 0.4 0.08 2.0 ---------------------------------------------------------------------------------------------------------------- LPG.................... Tier 0............ 0.41 ......... 3.4 1.0 0.20 2.0 LPG.................... Tier 1............ 0.41 0.25 3.4 0.4 0.08 2.0 ---------------------------------------------------------------------------------------------------------------- Full Useful Life Standards\5\ ---------------------------------------------------------------------------------------------------------------- Natural Gas............ Tier 1............ ......... 0.31 4.2 0.6 0.10 ............ LPG.................... TIer 1............ ......... 0.31 4.2 0.6 0.10 ............ ---------------------------------------------------------------------------------------------------------------- \1\Crankcase emissions are prohibited. Standards apply at all altitudes. For Tier 1 standards, vehicles are required to meet both the intermediate and full useful life standards. \2\The Tier 1 standards apply to 40 percent of a manufacturer's optionally certified 1994 model year vehicles, 80 percent of optionally certified 1995 vehicles, and 100 percent of optionally certified 1996 vehicles. The Tier 0 standards apply to optionally certified pre-1996 model year vehicles not covered by the Tier 1 standards. \3\Tier 0 particulate standards apply to diesel-cycle vehicles only. Tier 1 particulate standards apply to all vehicles. \4\Five years or 50,000 miles, whichever occurs first. \5\Ten years or 100,000 miles, whichever occurs first. No full useful life Tier 0 standards. Table 2.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Light Light-Duty Trucks (g/mi)\1\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Evaporative Fuel LVW (lb)\2\ Standards\3\ THC NMHC CO NOx PM\4\ Idle CO (% hydrocarbons conc.) (g/test) -------------------------------------------------------------------------------------------------------------------------------------------------------- Intermediate Useful Life Standards\5\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Natural Gas........................... 0-3750 Tier 1...... ........... 0.25 3.4 0.4 0.08 .......... ............ Natural Gas........................... 3751-5750 Tier 1...... ........... 0.32 4.4 0.7 0.08 .......... ............ LPG................................... 0-3750 Tier 1...... ........... 0.25 3.4 0.4 0.08 .......... ............ LPG................................... 3751-5750 Tier 1...... ........... 0.32 4.4 0.7 0.08 .......... ............ -------------------------------------------------------------------------------------------------------------------------------------------------------- Full Useful Life Standards\6\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Natural Gas........................... 0-3750 Tier 0...... ........... 0.67(0.83) 10(14) 1.2 0.26 0.50 2.0(2.6) Natural Gas........................... 0-3750 Tier 1...... ........... 0.31 4.2 0.6 0.10 0.50 2.0(2.6) Natural Gas........................... 3751-5750 Tier 0...... ........... 0.67(0.83) 10(14) 1.7 0.13 0.50 2.0(2.6) Natural Gas........................... 3751-5750 Tier 1...... ........... 0.40 5.5 0.97 0.10 0.50 2.0(2.6) LPG................................... 0-3750 Tier 0...... 0.80(1.0) .......... 10(14) 1.2 0.26 0.50 2.0(2.6) LPG................................... 0-3750 Tier 1...... 0.80 0.31 4.2 0.6 0.10 0.50 2.0(2.6) LPG................................... 3751-5750 Tier 0...... 0.80(1.0) .......... 10(14) 1.7 0.13 0.50 2.0(2.6) LPG................................... 3751-5750 Tier 1...... 0.80 0.40 5.5 0.97 0.10 0.50 2.0(2.6) -------------------------------------------------------------------------------------------------------------------------------------------------------- \1\Crankcase emissions are prohibited. Standards in parenthesis apply to vehicles sold in specified high-altitude counties. For the Tier 1 standards, vehicles are required to meet both the intermediate and full useful life standards. \2\Loaded vehicle weight (i.e., curb weight plus 300 lb.). \3\The Tier 1 standards apply to 40 percent of a manufacturer's optionally certified 1994 model year vehicles, 80 percent of optionally certified 1995 vehicles, and 100 percent of optionally certified 1996 model year vehicles. The Tier 0 standards apply to optionally certified pre-1996 model year vehicles not covered by the Tier 1 standards. \4\Tier 0 particulate standards apply to diesel-cycle vehicles only. Tier 1 particulate standards apply to all vehicles, but are phased in beginning one year later than the other Tier 1 standards. \5\Five years or 50,000 miles, whichever occurs first. \6\For Tier 0 standards eleven years or 120,000 miles, whichever occurs first. For Tier 1 standards ten years or 100,000 miles, whichever occurs first. Table 3.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Heavy Light-Duty Trucks (g/mi)\1\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Idle CO Evaporative Fuel Weight\2\ Standards\3\ THC NMHC CO NOX PM\4\ (% hydrocarbons conc.) (g/test) -------------------------------------------------------------------------------------------------------------------------------------------------------- Intermediate Useful Life Standards\5\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Natural Gas.................................. 3751-5750.... Tier 1 ........... 0.32 4.4 0.7 ....... ....... ............ Natural Gas.................................. >5750........ Tier 1 ........... 0.39 5.0 1.1 ....... ....... ............ LPG.......................................... 3751-5750.... Tier 1 ........... 0.32 4.4 0.7 ....... ....... ............ LPG.......................................... >5750........ Tier 1 ........... 0.39 5.0 1.1 ....... ....... ............ -------------------------------------------------------------------------------------------------------------------------------------------------------- Full Useful Life Standards\6\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Natural Gas.................................. 0-3750....... Tier 0 ........... 0.67(0.83) 10(14) 1.2 0.26 0.50 2.0(2.6) Natural Gas.................................. >3750........ Tier 0 ........... 0.67(0.83) 10(14) 1.7 0.13 0.50 2.0(2.6) Natural Gas.................................. 3751-5750.... Tier 1 ........... 0.46 6.4 0.98 0.10 0.50 2.0(2.6) Natural Gas.................................. >5750........ Tier 1 0.56 7.3 1.53 0.12 0.50 2.0(2.6) LPG.......................................... 0-3750....... Tier 0 0.80(1.0) 10(14) 1.2 0.26 0.50 2.0(2.6) LPG.......................................... >5750........ Tier 0 0.80(1.0) 10(14) 1.7 0.13 0.50 2.0(2.6) LPG.......................................... 3751-5750.... Tier 1 0.80(1.0) 0.46 6.4 0.98 0.10 0.50 2.0(2.6) LPG.......................................... >5750........ Tier 1 0.80(1.0) 0.56 7.3 1.53 0.12 0.50 2.0(2.6) -------------------------------------------------------------------------------------------------------------------------------------------------------- \1\Crankcase emissions are prohibited. Standards in parentheses apply to vehicles sold in specified high-altitude counties. For the Tier 1 standards, vehicles are required to meet both the intermediate and full useful life standards. \2\For Tier 0 standards the weight classification is loaded vehicle weight (i.e., curb weight plus 300 lb). For Tier 1 standards the weight classification is adjusted loaded vehicle weight (i.e., the average of curb weight and gross vehicle weight). \3\The Tier 1 standards apply to 50 percent of a manufacturer's optionally certified 1996 model year vehicles, and 100 percent of 1997 and later vehicles. The Tier 0 standards are optional before the 1995 model year and apply to optionally certified 1995 and 1996 model year vehicles not covered by the Tier 1 standards. \4\The Tier 0 particulate standards apply to diesel-cycle vehicles only. The Tier 1 particulate standards apply to all vehicles, but are phased in beginning one year later than the other Tier 1 standards. \5\Five years or 50,000 miles, whichever occurs first. \6\Eleven years or 120,000 miles, whichever occurs first. Table 4.--Emissions Standards for 1997 and Later Model Year Gaseous-Fueled Heavy-Duty Engines g/BHP-hr\1\ -------------------------------------------------------------------------------------------------------------------------------------------------------- Idle CO Evaporative Fuel Combustion GVW THC NMHC CO NOX\2\ PM (% hydrocarbons cycle conc.) (g/test) -------------------------------------------------------------------------------------------------------------------------------------------------------- Natural Gas.......................................... Otto......... 8501-14000 ....... 0.9 14.4 5.0 ....... 0.50 3.0 Natural Gas.......................................... Otto......... >14000 ....... 1.7 37.1 5.0 ....... 0.50 4.0 LPG.................................................. Otto......... 8501-14000 1.1 ....... 14.4 5.0 ....... 0.50 3.0 LPG.................................................. Otto......... >14000 1.9 ....... 37.1 5.0 ....... 0.50 4.0 Natural Gas.......................................... Diesel....... 8501-14000 ....... 1.2 15.5 5.0 \3\0.10 0.50 3.0 Natural Gas.......................................... Diesel....... >14000 ....... 1.2 15.5 5.0 \3\0.10 0.50 4.0 LPG.................................................. Diesel....... 8501-14000 1.3 ....... 15.5 5.0 \3\0.10 0.50 3.0 LPG.................................................. Diesel....... >14000 1.3 ....... 15.5 5.0 \3\0.10 0.50 4.0 -------------------------------------------------------------------------------------------------------------------------------------------------------- \1\g/BHP-hr = grams per brake horsepower hour. Crankcase emissions are prohibited beginning with the 1998 model year. \2\The NOX standard is 4.0 g/BHP-hr for all 1998 and later model year HDEs. \3\For optional compliance prior to the 1997 model year this standard is 0.10 g/BHP-hr for the 1994 and later model year, except for urban bus engines. For urban bus engines the optional standards are 0.07 g/BHP-hr for the 1994 and 1995 model years, and 0.05 g/BHP-hr for the 1996 model year. The required standard for 1997 and later model year urban bus engines is 0.05 g/BHP-hr. For the purposes of these standards, the current scheme of classifying vehicles as either Otto-cycle or diesel is being extended to gaseous-fueled vehicles, with some modifications as described below. This classification scheme was promulgated with the methanol standards to group engines regardless of fuel type in a manner that would provide equivalent control. Although there are other factors to consider, in general an Otto- cycle engine is considered to be one that is throttled during normal operation whereas a diesel is not. The Agency recognizes, however, that in some cases this criterion may not be adequate or appropriate to determine a vehicle's classification. For example, a gaseous-fueled engine which is derived from a particular Otto-cycle or diesel base engine, and is expected to be used in similar applications as the base engine, would most appropriately be classified the same as the base engine from which it was derived. In such cases the Administrator will take into account other relevant factors, such as compression ratio, combustion and thermodynamic characteristics, or intended in-use duty cycle when classifying the vehicle. Today's rule establishes the same evaporative emission requirements for gaseous-fueled vehicles which were recently adopted for other vehicles.\5\ The Agency recognizes that due to the sealed nature of gaseous-fueled vehicle fuel systems, emissions of unburned fuel from the fuel system are expected to be near-zero. However, the evaporative requirements are being adopted to assure leak-free fuel systems. --------------------------------------------------------------------------- \5\58 FR 16002, March 24, 1993. --------------------------------------------------------------------------- Today's rule establishes refueling requirements for gaseous-fueled light-duty vehicles and light-duty trucks, as well as refueling stations. Natural gas-fueled vehicles must be equipped with a refueling receptacle which meets the requirements of the recently adopted ANSI/ AGA NGV1 standard for refueling couplings. Natural gas refueling stations will not be allowed to vent more than 1.2 grams natural gas due to refueling nozzle disconnect. The applicable dates for these standards are discussed in the timing section of today's rule. For LPG vehicles there are two requirements. First, all LPG vehicle refueling stations will be required to use nozzles which have very low dead volume (2.0 cm\3\) from which fuel would be vented upon nozzle disconnect. This requirement was derived from the recently promulgated onboard refueling vapor recovery standard. For a complete description of the derivation please consult the summary and analysis of comments document. Second, LPG-fueled light-duty vehicles and light-duty trucks will be subject to the onboard refueling emission standards, adjusted for the difference in LPG energy density as compared to gasoline. This adjusted standard is 0.15 grams per gallon of LPG dispensed. The applicable dates for these standards are discussed in the timing section of today's rule. Additionally, for any LPG vehicle that contains a fixed liquid level valve (i.e., ``outage valve''), the refueling test will be performed with the liquid level valve in the open position unless the manufacturer can demonstrate to the satisfaction of the Administrator, that the fixed liquid level gauge would not be opened during refueling in ordinary use due to inaccessibility or other reasons. EPA recognizes that, although it did propose the control of refueling emissions from gaseous-fueled vehicles, the proposal did not include specific numerical standards as contained in today's rule. However, EPA believes that this action will be noncontroversial, and the Agency anticipates no significant comments regarding it. Nonetheless, the public is advised that these elements of today's action dealing with refueling emissions will be effective 60 days from the date of this Federal Register notice, unless notice is received within 30 days that interested parties wish to submit adverse or critical comments on that element of this action. If such notice is received, this action will be withdrawn and two subsequent notices will be published. One notice, which would be published before the effective date, will withdraw the final action. Another notice will begin a new rulemaking by announcing a proposal of the action and establishing a comment period. There is reason to believe that, in the case of some of the above- mentioned pollutants and vehicle classes, the levels of emissions will normally be substantially below the levels of the applicable standards. In such cases today's rule includes provisions for a waiver of certification testing requirements which allow a manufacturer to certify the vehicle or engine without performing the actual certification testing for which a waiver has been granted, similar to the waivers available for heavy-duty diesel engine CO, methanol vehicle and engine smoke and particulate, and Otto-cycle light-duty vehicle and light-duty truck particulate standards.\6\ A certification testing waiver can be obtained by demonstrating that, by virtue of a vehicle's design, it will always meet the standard for which the waiver was granted. This demonstration can be in the form of development testing data or other engineering data. It should be noted that these waivers only apply to certification testing requirements and do not relieve the manufacturer of liability for meeting the standard. Vehicles which have been certified using these waiver provisions also remain subject to selective enforcement audit (SEA) and in-use testing. The waivers provided in today's rule are available for all gaseous-fueled vehicle evaporative and refueling standards, gaseous-fueled heavy-duty diesel CO (including idle CO), particulate and smoke standards, and particulate standards for light-duty vehicles and light-duty trucks. --------------------------------------------------------------------------- \6\47 FR 49811, November 2, 1982; 54 FR 14426, April 11, 1989; and 56 FR 25724, June 5, 1991. --------------------------------------------------------------------------- Today's rule allows gaseous-fueled vehicles to demonstrate compliance with emission standards through averaging, trading and banking in the same manner as vehicles operated on other fuels. Gaseous-fueled vehicles will be treated similarly to methanol-fueled vehicles with respect to the constraints of the various programs. For a more detailed discussion of how gaseous-fueled vehicles fit into these programs please consult the public docket for this rulemaking.\7\ As explained above, in addition to new vehicles and engines, today's rule allows manufacturers to include in the averaging, trading and banking programs 1994 model year vehicles and engines manufactured before the rule's effective date, but identical to 1994 model year vehicles and engines manufactured after the effective date. --------------------------------------------------------------------------- \7\Public docket A-92-14, item III-B-2. --------------------------------------------------------------------------- Today's rule delays the applicability of federal on-board diagnostics (OBD) requirements for natural gas-fueled light-duty vehicles and light-duty trucks until the 1998 model year. As finalized in the February 19, 1993 OBD rule\8\ those requirements were scheduled to take effect with the 1994 model year for all vehicles for which emission standards exist. However, due to the feasibility issues unique to natural gas-fueled vehicles, these requirements are being delayed until the 1998 model year. OBD I requirements will apply to natural gas vehicles in the 1997 model year, as well as those natural gas vehicles optionally certified prior to the 1997 model year. The OBD requirements contained in the OBD rule will apply to liquefied petroleum gas-fueled light-duty vehicles and light-duty trucks beginning with optionally certified vehicles in the 1994 model year. --------------------------------------------------------------------------- \8\58 FR 9468, February 19, 1993. --------------------------------------------------------------------------- C. Certification Test Fuel Specification The certification test fuels in today's rule are intended to represent the actual fuels gaseous-fueled vehicles are likely to see in-use. Given the wide range of in-use fuel compositions, the certification fuels are broadly defined. In the case of natural gas, the certification fuel specifications include a minimum methane content of 89 percent, as well as maximum levels for the other prominent hydrocarbons found in natural gas (e.g., ethane, propane). Certification fuel under this approach reflects over 90 percent of the natural gas available in the United States. Most of the gas not meeting this criteria is gas being sold in high altitude areas, where higher levels of inert gases are added to the natural gas. Significantly less is known about the variability of in-use LPG composition. However, the Agency believes that the composition of LPG is more consistent than that of natural gas due to common carrier pipeline and import tariff constraints. Thus, the Agency is adopting commercially available LPG as the certification fuel for LPG vehicles. As more information becomes available on LPG composition, and as experience with LPG vehicles increases, the need for a more well- defined LPG certification fuel may become apparent. Should this happen, EPA would take steps at that time to develop an appropriate LPG certification fuel specification. It should be noted that the Agency is not including any controls on in-use natural gas or LPG in today's rule, but intends to monitor in-use fuels to ensure that the certification fuels remain representative. D. Test Procedures For the most part, the current test cycles, and measurement and analytical procedures can be directly applied to gaseous-fueled vehicles. Thus, the test procedures contained in today's rule are largely the same as those which apply to other, currently regulated vehicles. The only exception of note is the procedure for measuring NMHC emissions from natural gas-fueled vehicles. The current procedure for measuring NMHC emissions was adopted in the Tier 1 rule.\9\ While this procedure works fairly well for currently regulated vehicles, it is not nearly as accurate for natural gas-fueled vehicles due to their much higher levels of exhaust methane. Thus, today's rule contains some slight modifications to the NMHC test procedures adopted for the Tier 1 standards\10\ to allow more accurate NMHC measurement from natural gas- fueled vehicles. These changes include accounting for the different flame ionization detector (FID) response to methane as opposed to the other hydrocarbons, as well as the use of fuel densities and H/C ratios in the calculations which are more appropriate to natural gas vehicles. The Agency views this as an interim measure and is currently working with the California Air Resources Board and the American Automobile Manufacturers Association as part of a cooperative research and development agreement to develop a more accurate procedure for the direct measurement of NMHC. --------------------------------------------------------------------------- \9\56 FR 25724, June 5, 1991. \10\56 FR 25724, June 5, 1994. --------------------------------------------------------------------------- E. Fuel Economy Today's rule contains fuel economy test procedures and calculations for measuring the fuel economy of natural gas-fueled light-duty vehicles and light-duty trucks. The driving cycles adopted for natural gas vehicles are the same as those currently in place for gasoline- fueled vehicles. Also, the measurement and calculation procedures for natural gas vehicles rely on the same principle of carbon balance as the current gasoline procedures, but include a gasoline/natural gas equivalency factor of 100 standard cubic feet of natural gas equalling 0.823 gallons of gasoline. These procedures and calculations will allow these vehicles to be included in a manufacturer's corporate average fuel economy (CAFE) under the Motor Vehicle Information and Cost Savings Act (MVICSA), 15 U.S.C. Sec. 2001 et seq. The Alternative Motor Fuels Act of 1988,\11\ provides that alternative fueled vehicles (including natural gas-fueled vehicles) may be included in a manufacturer's CAFE calculation on a favorable basis in order to encourage the manufacture of such vehicles. The AMFA provides that, for purposes of including natural gas vehicles in the CAFE calculation, fuel consumption of natural gas vehicles is only fifteen percent of equivalent gasoline fuel consumption. The AMFA also mandates the 0.823 gasoline/natural gas equivalency factor included in today's rule. Regulations governing the calculation and use of natural gas vehicle CAFE credits are contained in a separate rulemaking action.\12\ --------------------------------------------------------------------------- \11\Public Law 100-494, October 14, 1988. \12\56 FR 8856, March 1, 1991. --------------------------------------------------------------------------- As will be discussed further in the Public Participation section of this rule, the Agency is not promulgating fuel economy procedures for LPG vehicles today, but will do so in a separate rulemaking action. F. Aftermarket Conversions Today's rule contains provisions for the certification of aftermarket conversions (i.e., conversions which allow a vehicle or engine to operate on a fuel other than the fuel for which it was originally designed and certified). An exemption from the tampering prohibitions contained in section 203(a)(3) of the Clean Air Act can be secured through this certification process. The provisions contained in today's rule for securing such an exemption consist of three main parts: applicable standards, test procedures, and warranty/liability issues. It has always been the Agency's policy that an aftermarket conversion not degrade the emissions performance of the original vehicle as a condition of being exempt from prosecution for tampering violations. Today's rule merely clarifies that policy by providing specific procedures by which one can certify that a conversion does meet this requirement, and thus secure an exemption from the tampering prohibition. Consistent with this policy, the emission standards which an aftermarket conversion shall meet in order to secure the tampering prohibition exemption are essentially the same standards the original vehicle was certified as meeting. In the case of conversions to natural gas, the converted vehicle would not be required to meet the THC standard, but must meet an NMHC standard which provides an equivalent amount of NMHC control as that afforded by the original THC standard. In the case of conversion to multi-fuel operation (i.e., where the vehicle has the ability to switch between two fuels, such as gasoline and natural gas, or where the vehicle operates on two fuels simultaneously, but retains the ability to operate exclusively on the original fuel), the vehicle would still be required to meet the emission standards it was originally certified to when operating on the original fuel, in addition to meeting the applicable requirements on the new fuel. The test procedures applicable to aftermarket conversions under this program are those currently in place new vehicle certification as outlined in 40 CFR Part 86. The small volume manufacturers certification program contained in 40 CFR 86.092-14 is also available for aftermarket conversion certification provided the company or individual seeking certification meets the sales limits described in that section. These procedures utilize the same test cycles and analytical procedures that are used for new vehicle certification. In the case of aftermarket conversions a certificate of conformity must be sought for each engine family/conversion system combination and for each model year vehicle for which the system is intended. As a condition of exemption from the tampering prohibition, conversion manufacturers and installers must accept in-use liability for warranty and recall as outlined in section 207 of the Act and its implementing regulations.\13\ This is consistent with EPA's policy that aftermarket conversions not degrade the emissions performance of the original vehicle. It will also assure that the conversion will meet the applicable emission standards throughout its useful life. Since conversions generally rely, at least in part, on emission control equipment already on the original vehicle for emissions control, the useful life of a conversion will not extend beyond the useful life of the original vehicle. --------------------------------------------------------------------------- \13\Code of Federal Regulations, Title 40, Part 86. --------------------------------------------------------------------------- G. Fees Under section 217 of the Clean Air Act, EPA may establish fees to recover all reasonable costs incurred for activities associated with the Motor Vehicle and Engine Compliance Program (MVECP). The MVECP includes all compliance and enforcement activities performed by EPA which are associated with certification, fuel economy, Selective Enforcement Auditing (SEA), and in-use compliance activities. In July of 1992 EPA established these fees, to be effective with the 1993 model year.\14\ These fees, as stated in the fees rule, cover all direct and indirect costs incurred by EPA for the MVECP, and automatically apply to gaseous-fueled vehicles and engines now that the MVECP applies to such vehicles and engines. Since the fees are based on the costs incurred by EPA, and since today's regulations are basically an extension of the current MVECP, the fees currently in effect for other vehicles apply to gaseous-fueled vehicles, without modification. No regulatory changes are needed and none are being made. The applicable fee must be paid, for each engine family, before the Certification Division can begin a review of the application for certification. --------------------------------------------------------------------------- \14\57 FR 30044, July 7, 1992. --------------------------------------------------------------------------- III. Public Participation A number of interested parties commented on EPA's November 5, 1992 NPRM. The comments include written submittals to the rulemaking docket and those presented at the December 3, 1992 public hearing, which was held in Ann Arbor, Michigan. The Agency has fully considered these comments in developing today's final rule. This section describes the major issues of the rulemaking, as reflected in the public comments. The discussion of each issue opens with a brief description of what was proposed followed by a summary of the significant comments and EPA's analysis of the issue. The reader is referred to the Summary and Analysis of Comments document for the complete details of EPA's analysis. That document is available in the rulemaking docket. (For information on access to the docket, see the ``Addresses'' section above.) A. Timing of Requirements Summary of the proposal: As was stated in the NPRM, the Agency believes that the proposed standards are not technology-forcing, and that they could be met largely through currently available technology. Thus, the only leadtime requirement for meeting the proposed standards would be that of actually going through the certification process itself, including the required durability showing. The Agency, therefore, proposed that the new vehicle emission standards be effective with the 1994 model year, and that the aftermarket conversions take effect on January 1, 1994. Additionally, the Agency proposed that manufacturers have the option of complying with these standards prior to the effective date in order to participate in any applicable emissions averaging, trading and banking programs, as well as the CAFE program in the case of natural gas-fueled light-duty vehicles and light-duty trucks. Summary of the comments: In general, the comments received in response to the issue of leadtime supported EPA's assessment that these standards are not technology-forcing in the sense that fundamentally new technology must be developed. However, a number of commenters raised concerns that, although the basic technology required to meet these standards has been demonstrated at low mileage, the durability of this technology in many cases remains to be proven. Additionally, one commenter pointed out that there are several mandated requirements taking effect in the next few years for new vehicles, including Tier 1 and cold CO standards, on-board diagnostics, and revised evaporative procedures, and that mandating gaseous-fueled vehicle certification with little leadtime may seriously impair the introduction of these vehicles into the marketplace. Most commenters suggested that, given the need for technology refinement and durability work, these requirements should not take effect until the 1996 or 1997 model year. In addition, the heavy-duty engine manufacturers asserted that, under section 202(a)(3)(C) of the Clean Air Act, EPA is required to provide four years leadtime in the case of any new emission standards. In most cases commenters stated that, regardless of what effective date EPA finalizes, they support the option of being able to certify prior to the effective date. EPA response to comments: The Agency agrees that, while current gaseous-fueled vehicle technology is generally capable of meeting the emission standards contained in today's rule, work remains in some cases to meet the durability requirements. While the Agency believes that some current gaseous-fueled engine technologies are capable of demonstrating the required emissions durability, it does not believe this is the case with some of the newest technologies being developed. Given that each engine family must demonstrate durability during the new vehicle certification process, the Agency believes that not providing adequate leadtime may hinder the further development of new gaseous-fueled vehicle technology in the short term, which is contrary to the stated intent of this rule. Thus, today's requirements for new vehicles and engines will take effect with the 1997 model year as requested by some commenters. Manufacturers will have the option to comply with these provisions prior to the 1997 model year if they choose. The Agency does not believe that this amount of leadtime will be a problem from an environmental standpoint for two reasons. First, the volume of new gaseous-fueled vehicles produced prior to the 1997 model year is not expected to be that large, given the relatively young nature of the new gaseous-fueled vehicle market. Second, the Agency expects that any new vehicle or engine family which might be sold in any significant volume prior to the 1997 model year would have demonstrated adequate durability. Since there is much incentive for early compliance in the form of CAFE credits and the emissions banking and trading program, the Agency would expect the manufacturers of these vehicles to certify them in order to take advantage of these credits. Additionally, the Agency does not believe that it is required to provide four years leadtime for new gaseous-fueled heavy-duty engine standards because these standards are being promulgated under the general authority of section 202(a)(1). However, as will be discussed in the section on CO and crankcase emissions, the Agency has elected to provide four years of leadtime in the case of crankcase emission controls. For further discussion of the four year leadtime issue please consult the summary and analysis of comments document in the docket. Finally, manufacturers have the option of complying with these requirements prior to their effective date (including certification retroactive to the beginning of the 1994 model year) and can include such certified engines in the averaging, banking and trading program. B. Standards for HC 1. NMHC vs. THC Standards Summary of the proposal: Since natural gas is primarily methane, natural gas-fueled vehicles (NGV) tend to have fairly high levels of methane emissions in their exhaust HC. Due to the difficulty current catalyst formulations have in oxidizing methane, it is not currently feasible for NGVs to meet the same THC standards that other vehicles meet. Thus, only NMHC standards were proposed for NGVs, with the Agency deferring any action on THC standards for NGVs until such time as the necessary methane control technology can be developed. LPG fuel, however, contains no methane, and the exhaust methane levels associated with LPG vehicles tend to be much closer to those from petroleum-fueled vehicles. Thus, all applicable THC and NMHC standards were proposed for LPG vehicles. Summary of the comments: The Agency's decision to defer action on THC standards for NGVs received very broad support. Only the Manufacturers of Emission Controls Association (MECA) disagreed with this approach. MECA contended that without some form of technology- forcing THC standard for NGVs, most work on methane control technology would likely stop. MECA also pointed out that the Agency has, in the past, used technology-forcing standards as impetus for the development of new emission control technology. Several commenters suggested that the approach of exempting NGVs from THC standards should be applied to LPG vehicles as well, citing a potential unfair advantage for NGVs if LPG vehicles were required to meet THC standards. Additionally, the LP Gas Clean Fuels Coalition stated that LPG vehicles have substantially higher levels of methane emissions than their petroleum-fueled counterparts, and thus should also be exempt from meeting the THC standards. The Coalition, however, did not submit any data in support of this claim. EPA response to the comments: The Agency continues to believe that action on the THC standards for NGVs should be deferred. The Agency continues to be concerned that compliance with the THC standard currently in place for other fuels is infeasible for NGVs. While the Agency has received data suggesting that the THC standards are technically achievable for NGVs, no data has been submitted concerning the cost of refining and implementing the necessary technology on a commercial level. Cost is a component of feasibility, and without cost information the Agency cannot conclude that compliance with the THC standards is feasible. Moreover, technical issues remain to be resolved. The data suggesting that THC standards are technically achievable was limited to vehicles operating at a stoichiometric fuel/ air ratio, and operation under other conditions (i.e., lean burn) remains an issue. Additionally, the durability of methane-specific catalysts remains an unknown. Also, for the reasons explained in the proposal, EPA does not believe it can establish a technology-forcing standard. EPA continues to believe that the amount of lead-time required for adequate technology development still cannot be readily determined, because the durability of a methane catalyst formulation has not been established. EPA does not agree that the absence of a technology-forcing standard would bring work on methane control technology to a stop. The engine manufacturing industry has indicated that its research will continue based on the belief that THC standards will be imposed in the future. Also, as noted in the proposal, EPA believes that strong growth in the NGV market in the near-term is important to provide resources for technology development. Of course, EPA will continue to monitor work on methane catalyst development. If information becomes available establishing the technology's feasibility (including cost information), EPA will consider adopting THC standards for NGVs. Also, if future events further demonstrate the need for a technology-forcing standard, EPA will further consider this option as well. As was stated in the NPRM, the Agency believes it most appropriate to, wherever possible, apply the same standards to alternative-fueled vehicles that apply to their petroleum-fueled counterparts. In the case of NGVs there are circumstances, as discussed above, which justify deviating from this basic philosophy. However, the Agency has seen no emissions data which would suggest that a similar set of circumstances exists for LPG vehicles. Thus, LPG vehicles will be required to meet the same THC standards as currently apply to other vehicles. 2. Heavy-Duty NMHC Standards Summary of the proposal: In setting NMHC standards for natural gas- fueled heavy-duty engines (HDE), the Agency intends to establish standards which would provide the same level of NMHC control as the THC standards in effect for petroleum diesel and gasoline HDEs. In the absence of speciated exhaust HC data on HDEs (i.e., data on the level of the individual HC components in the exhaust), EPA applied the results of an analysis done on light-duty vehicles and light-duty trucks to arrive at NMHC standards which were 82.5 percent of the level of the corresponding THC standards. The resultant standards were very close to those adopted by the California Air Resources Board (CARB), and in the NPRM the Agency requested comment on whether it should adopt CARB's standards instead. Summary of the comments: Every commenter who expressed an opinion on this issue urged EPA to adopt the CARB standards in order that the California and federal standards be harmonized. EPA response to the comments: The Agency believes that the differences between its proposed NMHC standards and CARB's are so small as not to be an air quality issue. Further, EPA has learned since the NPRM that the CARB standards were based on speciated data from HDEs. Thus, as EPA believes that the speciated data provides a sounder basis than EPA's, the Agency is adopting CARB's NMHC standards for HDEs. 3. Evaporative Emission Standards Summary of the proposal: In the NPRM it was noted that, due to the sealed nature of gaseous-fueled vehicle fuel systems, their ``evaporative'' emissions (i.e., emissions of unburned fuel from the fuel storage system) are expected to be near-zero. Nonetheless, the Agency proposed evaporative emission controls for gaseous- fueled vehicles in order to assure that the fuel systems are not leaking. EPA proposed that the evaporative provisions for gasoline and methanol- fueled vehicles, which were in the process of being revised at the time of the proposal for this rule, be applicable to gaseous-fueled vehicles as well, with modifications to the test procedures as necessary to accommodate gaseous fuels. The Agency also proposed that certification testing waivers be available for evaporative testing in order to reduce the testing burden as much as possible, given the likelihood of near- zero emissions. Summary of the comments: Although one commenter supported the proposed evaporative requirements for gaseous-fueled vehicles, citing potential fuel leaks from the vehicle refueling receptacle, most of the comments received expressed opposition. In general, most commenters said that, for safety reasons, as well as to simply prevent the complete escape of fuel from the vehicle for economic reasons, the fuel systems must be sealed. Since sealed systems are a practical requirement of gaseous-fueled vehicles, they argued, there is no need for EPA to regulate evaporative emissions. As a result, any certification testing required would be unnecessary. Some commenters felt that if EPA were to require some form of evaporative emissions showing that it should be in the form of an engineering evaluation of the system, or simply a one hour diurnal test. EPA response to comments: The Agency agrees with the general comment that there are practical considerations other than emissions concerns which force the use of sealed fuel systems on gaseous-fueled vehicles. As a result, EPA would expect their evaporative emissions to be near-zero. However, the Agency believes that it is prudent to have some kind of evaporative emission standard which can be enforced, in order to assure that fuel system leaks do not become a problem. Thus, the same new evaporative provisions applicable to other vehicles beginning with the 1996 model year will also be applied to gaseous- fueled vehicles at that time, recognizing that compliance with these standards is optional prior to the 1997 model year. The Agency does recognize, however, that it is likely that, by virtue of their design, gaseous-fueled vehicles will emit well below the applicable standards. Therefore, certification testing waivers will be available for all gaseous-fueled vehicle evaporative provisions if the manufacturer can show that, by virtue of the vehicle's design, it will always meet the applicable standards. C. Refueling Emission Standards 1. Natural Gas Summary of the proposal: In the NPRM the Agency proposed that, in the case of natural gas refueling facilities, no refueling hoses which need to be vented down prior to disconnect shall be vented to the atmosphere. Rather, as is the case with many current natural gas refueling facilities, EPA expects that such vent-down gases should be routed back to the compressor inlet rather than being vented to the atmosphere. The timing of this requirement was not explicit in the NPRM preamble. However, the regulatory text stated that the provisions would take effect with the 1994 model year. Summary of the comments: In general, the comments received in response to the issue of natural gas refueling hose venting opposed, to some degree, the proposed prohibition on venting emissions. Some commenters suggested that this requirement is not needed at all given the extremely small contribution to total methane emissions that vent- down gases represent. Several commenters pointed out that the upcoming ANSI/AGA NGV1 standard would address EPA's concerns about refueling emissions from natural gas refueling stations. One commenter pointed out that this proposed requirement could be interpreted as a zero- emission standard and questioned the feasibility of such an approach. Some commenters suggested that more leadtime was needed than was proposed. Several commenters pointed out that the cost of controlling these emissions varied quite a bit depending on the inlet pressure of the compressor. In cases where the natural gas supply line is at fairly low pressure (i.e., 15 psi or less) the gas could be routed directly into the compressor inlet at low cost. However, in cases where the gas supply pressure is higher, additional compression equipment would be needed to compress the vent-down gas in order to route it back into the compressor, raising costs substantially. Also, the cost of such controls would be much higher for existing installations than for new stations because existing stations would likely require excavation for the return line plumbing. Finally, some commenters stated that EPA should not control natural gas refueling emissions since they are primarily methane, and the Agency only proposed NMHC standards for tailpipe emissions. EPA response to comments: In the NPRM the Agency mentioned that the natural gas industry was moving toward the establishment of standard refueling equipment specifications. That effort, known as the ANSI/AGA NGV1 standard, was recently adopted by the American National Standards Institute (ANSI) as the standard for natural gas vehicle fueling connection devices. While in its various draft forms, this standard contained a provision limiting the amount of natural gas that can be vented due to nozzle disconnect. This provision was based on the proposed onboard refueling vapor recovery (ORVR) standard for gasoline- fueled vehicles of 0.05 grams per gallon of dispensed gasoline.\15\ As indicated in the draft ANSI standard contained in the public docket for this rule, the venting provision was deleted from the final ANSI standard since, at the time of final balloting on the standard, the ORVR rule had not yet been promulgated. The ORVR final rule was recently promulgated and included a gasoline-fueled vehicle refueling emission standard of 0.20 grams per gallon of dispensed gasoline.\16\ --------------------------------------------------------------------------- \15\52 FR 31162, August 19, 1987. \16\59 FR 16262, April 6, 1994. --------------------------------------------------------------------------- The Agency agrees that a zero-emission standard for natural gas vehicles is not reasonable and believes that, in its draft form, the NGV1 standard addressed EPA's concerns with natural gas vehicle refueling emissions. Thus, the Agency is using the methodology in draft NGV1 standard to apply the 0.20 gram per gallon refueling standard to natural gas vehicles. Using this approach, natural gas refueling stations will be allowed to vent no more than 1.2 grams of natural gas due to nozzle disconnect. This standard is based on the ORVR standard of 0.20 grams per gallon of fuel dispensed and a nominal fuel tank capacity of six gallons gasoline equivalent natural gas, as was assumed in the draft NGV1 standard. For a more complete discussion of how this standard was derived please consult the summary and analysis of comments document for this rule. This requirement will take effect January 1, 1998 for high volume stations, with a two year extension until January 1, 2000 for small volume stations (those which dispense less than the energy equivalent of 10,000 gallons of gasoline per month based on the AMFA fuel equivalency factor). In addition to the requirements for natural gas refueling stations, EPA is also requiring in today's rule natural gas-fueled light-duty vehicles and light-duty trucks be equipped with refueling receptacles which comply with the recently adopted ANSI/AGA NGV1 standard. This requirement will be implemented consistent with the timing of the ORVR provisions for other vehicles (three year phase-in beginning with the 1998 model year for light-duty vehicles and the 2001 model year for light-duty trucks). The Agency expects, however, that all new natural gas- fueled vehicles will have ANSI/AGA NGV1 nozzles long before this due to the desire for standardized refueling coupling geometry within the industry. EPA does not believe that the cost of the refueling station controls is prohibitive and believes that today's requirement is both feasible and reasonable. Consistent with this view, most new stations being installed would meet this requirement. The Agency agrees that in certain cases, such as those where additional compression equipment is needed, the cost of retrofitting may not be reasonable. Thus, for in- use refueling stations which must be retrofitted to meet this requirement, the Agency will waive the requirement in situations where the station operator can demonstrate, to the satisfaction of the Administrator, that compliance with this provision would require the use of additional compression equipment, or other similar costs. The impact of such waivers should be minimal given the small number of stations currently operating, and the small percentage of those stations which would not currently meet these requirements. As was discussed earlier, the lack of exhaust THC standards in today's rule is a function of cost and legal constraints, and the Agency believes that control of methane is appropriate where it is feasible and economically reasonable. Thus, EPA does not believe that the desire to control refueling emissions from natural gas vehicles is inconsistent with the adoption of exhaust NMHC standards. 2. LPG Vehicle/Pump Interface Summary of the proposal: Since LPG is transferred in a sealed system there is little concern about refueling emissions at the vehicle/pump interface during the actual fuel transfer. Of concern to the Agency, however, are emissions released when the nozzle is disconnected from the vehicle. At this point any fuel which is trapped in the dead space between the nozzle and the vehicle receptacle is released. In the NPRM the Agency proposed that refueling equipment be designed so as to prevent this escape of fuel, such as through the use of low-loss, no-bleed couplings, although no specific numerical standards were included. As with the natural gas provisions in the NPRM, the timing of this requirement was not explicit in the NPRM preamble. However, the regulatory text stated that the provisions would take effect with the 1994 model year. Summary of the comments: The Agency received few comments on this particular aspect of the proposed refueling provisions. The comments that addressed this issue tended to agree with the need for control. However, the comments otherwise differed. One commenter suggested that any hardware requirement be performance-based, rather than prescriptive, so as to be consistent with EPA's previous consideration of refueling controls for gasoline vehicles. Also, the lack of a numerical standard was interpreted as being a zero-emission standard, which one commenter suggested is infeasible. Another commenter stated that just requiring new refueling nozzles at all current LPG fueling facilities would cost about $30 million, but provided no supporting documentation for that claim. EPA response to comments: The Agency believes that it is appropriate to minimize the amount of LPG fuel which is vented from the dead space between the refueling nozzle check valve and the vehicle refueling receptacle check valve but also agrees that a zero-emission standard is unreasonable. Both the nozzle and the vehicle receptacle geometries play an integral role in the size of this dead space. Thus, any performance specification for vehicle/pump interface refueling emissions would have to address the nozzle and receptacle as a single system. In the case of LPG, there is not a standardized geometry for refueling nozzles, at least in terms of the parameters which would affect this dead space. Thus, it is difficult for the Agency to define a performance specification such as that which has been considered for gasoline vehicles based upon an industry standard nozzle geometry. The Agency is aware that the LPG industry is developing nozzles which dramatically reduce the dead space, especially when used in conjunction with low-bleed inserts in the vehicle receptacle. For the reasons just mentioned EPA is finalizing a two-fold approach to refueling emissions for LPG vehicles. First, today's rule includes a requirement that LPG refueling nozzles have no more than 2.0 cm3 dead space, as measured from the face of the nozzle which seals against the vehicle receptacle ``O'' ring. Second, a refueling standard and SHED-based test consistent with the recently promulgated ORVR requirement is being adopted for LPG-fueled light duty vehicles and light-duty trucks. The vehicle standard, adjusted for the difference in energy density between gasoline and LPG, is 0.15 grams per dispensed gallon of fuel. This approach will ensure that the LPG vehicles will have refueling emissions similar to those of other vehicles meeting the ORVR standards. A certification testing waiver will be available for all classes of LPG vehicles to which this standard applies if the manufacturer can demonstrate, through the use of development or other data, that the vehicle will meet the standard. For a complete discussion of how the 2.0 cm3 standard for LPG vehicle refueling nozzles was derived please consult the summary and analysis of comments document for this rule. This standard for LPG vehicles will apply to the same classes and model years as the ORVR rule (i.e., three year phase-in beginning with the 1998 model year for light-duty vehicles and the 2001 model year for light-duty trucks). The requirement for the refueling nozzles will take effect January 1, 1998 for high volume stations, with a two year extension until January 1, 2000 for small volume stations (those which dispense less than the energy equivalent of 10,000 gallons of gasoline per month). The Agency believes that this amount of leadtime for refueling stations will allow for the replacement or retrofit of LPG nozzles during the normal course of replacement or repair of in-use nozzles due to wear. 3. LPG Tank Venting Summary of the proposal: Fuel tanks for LPG vehicles currently have a device known as a fixed liquid level valve, or outage valve, at the proper fill level. This is a small orifice which can be opened during refueling in order to indicate that, upon the release of liquid from the valve, the tank is filled and refueling should stop. Although LPG tanks are now constructed with built-in automatic shutoff devices to prevent overfilling, they still have outage valves on them. The Agency proposed a prohibition on all non-safety-related valves on gaseous- fueled vehicles in order to prevent the emissions of LPG from outage valves during refueling. Summary of the comments: The Agency received a variety of comments expressing concern about the proposal to eliminate outage valves from LPG vehicles. First, several commenters pointed out that outage valves are required under the National Fire Protection Association standard 58 (NFPA 58), and that the NFPA code has been adopted by many state and local fire marshals as the applicable fire code. Second, some commenters stated that the regulatory language as proposed precluded the use of all types of valves on gaseous-fueled vehicles, including such things as manual fuel shutoff valves. Third, some comments were received expressing concern that this requirement would preclude the use of liquefied natural gas (LNG) altogether due to the need to occasionally vent excess pressure from LNG fuel tanks to prevent overpressurization. Finally, one commenter expressed concern about the application of this requirement to LPG vehicles already in service and the possibility of having to retrofit those vehicles. EPA response to comments: The Agency understands the apparent conflict between its proposal and the requirements of NFPA 58. EPA believes that with the newer requirement in NFPA 58 for automatic shutoff (overfill prevention) mechanisms, the requirement for outage valves on vehicle fuel tanks is obsolete, and should be removed from NFPA 58. Due to this conflict, however, the Agency has chosen not to finalize its proposed requirements prohibiting outage valves, but is working with the industry and NFPA to have this requirement deleted from NFPA. While the Agency believes it has the authority to preempt NFPA 58 as adopted by fire marshals through the adoption of the proposed requirement to eliminate outage valves, it prefers to work with the industry to remove that requirement from NFPA 58 before superseding state and local law through EPA regulation. Given that the proposed language prohibiting non-safety-related valves is not being finalized, the other concerns expressed in the comments are alleviated. While the Agency is not finalizing the proposed requirements concerning outage valves, they remain a concern as a source of emissions. This is especially true for LPG vehicles which are intended to be certified as ILEVs. Thus, for any LPG vehicle, the above- mentioned refueling test procedure will be performed with the outage valve opened, unless the manufacturer can demonstrate, to the satisfaction of the Administrator, that the outage valve or any other such gauges or valves would not be opened during refueling in-use due to inaccessibility or other design features that would prevent or make it very unlikely that they could be opened. D. Standards for CO and Crankcase Emissions 1. Idle CO Summary of the proposal: Until the methanol emission standards were promulgated in 1989, idle CO standards were only applied to Otto-cycle engines. EPA reasoned that diesel vehicles always operate at such lean fuel/air ratios that their idle CO emissions would always be well below the standards. The methanol rule applied idle CO standards to all methanol-fueled vehicles because the Agency was aware of diesel methanol vehicles which were throttled at idle. This same reasoning was applied to gaseous-fueled vehicles, and EPA proposed that idle CO standards apply to all gaseous-fueled vehicles, not just Otto-cycle vehicles. Summary of the comments: The few comments EPA received on this issue were in opposition to idle CO standards for engines which operate at lean fuel/air ratios. The commenters stated that lean burn engines emit very low CO levels, and that there is no need to regulate and test for emissions which are inherently low. EPA response to the comments: The Agency recognizes that lean burn engines do traditionally have much lower CO emissions than vehicles operating at stoichiometric fuel/air ratios. However, EPA believes that not enough data yet exists on diesel gaseous-fueled vehicles to justify their exemption from the idle CO standards. The Agency is especially concerned about those diesel designs which employ throttling at idle. It is likely that these vehicles will have no problem meeting the idle CO standards by virtue of their design and that, this being the case, the only burden this standard presents is that of the actual certification testing and reporting. Thus, certification testing waivers for diesel gaseous-fueled vehicle idle CO standards will be available to manufacturers that can demonstrate through emissions test data or other engineering data that a vehicle will, by virtue of its design, always emit at levels well below that of the applicable idle CO standard. 2. Crankcase Emissions Summary of the proposal: Currently, all vehicles and engines, with the exception of non-naturally aspirated petroleum heavy-duty diesel engines (HDDE), are prohibited from discharging crankcase emissions into the atmosphere. The current prohibition is not applicable to non- naturally aspirated petroleum HDDEs due to concerns that the routing of oil mist-laden crankcase gases through turbochargers and other air handling equipment may foul this equipment. With the issuance of the methanol vehicle emission standards in 1989 this prohibition was applied to all methanol HDDEs whether they were naturally aspirated or not. The reasoning was that methanol engine crankcase gases were expected to be cleaner than petroleum diesel engine crankcase gases, and closer to gasoline engine crankcase emissions which are been routinely routed through turbochargers. Given that gaseous-fueled vehicles are also expected to have cleaner crankcase emissions than petroleum diesels, this prohibition on crankcase emissions was proposed to be applicable to all gaseous-fueled vehicles and engines as well, with no exemption for non-naturally aspirated, gaseous-fueled HDDEs. Summary of the comments: In general, the comments received in this area were in opposition to crankcase controls for gaseous-fueled vehicles and engines. Some commenters suggested that crankcase controls only be applied to naturally-aspirated gaseous-fueled engines, as is currently the case with petroleum HDDEs. Others stated that, due to their inherently low emissions, gaseous-fueled vehicles and engines should be exempt from all crankcase emission provisions. One commenter expressed concern about crankcase gases possibly fouling turbochargers, and then went on to say that gaseous-fueled vehicle crankcase emissions will be inherently clean and thus do not need to be regulated. EPA response to comments: In the absence of compelling data showing that gaseous-fueled vehicle crankcase emissions are cleaner than those of their petroleum-fueled counterparts, the Agency believes it is prudent to extend the coverage of the current prohibition on crankcase emissions to include gaseous-fueled HDDEs. Additionally, EPA believes that, since the crankcase prohibition for methanol-fueled HDDEs is not limited to naturally-aspirated engines, as well as the fact that crankcase emissions are routinely routed through gasoline engine turbochargers, there is no reason to exempt non-naturally aspirated gaseous-fueled vehicles and engines from the crankcase emissions prohibition. As was noted in the leadtime discussion, the Agency expects that current technology gaseous-fueled engines will be able to meet these standards, and therefore the minimum amount of leadtime to allow for certification has been given. However, since turbocharged gaseous-fueled HDDEs are generally derived from turbocharged petroleum HDDEs they do not tend to have crankcase emission controls. The Agency believes that, while the four year leadtime requirement in section 203(a)(3)(C) of the Act is not legally binding in the case of gaseous- fueled heavy-duty engines, in circumstances where the manufacturers must make changes to engine designs similar to those made to comply with changes in gasoline or petroleum diesel requirements, section 203(a)(3)(C) may constitute a proper default period. In order to allow for the early introduction of gaseous-fueled HDDEs, the Agency is providing four years leadtime for crankcase controls on turbocharged gaseous-fueled HDDEs in the absence of factors indicating that another period is more appropriate. Thus, this provision will take effect for the 1998 model year. It should be noted that the four years of leadtime only applies to turbocharged gaseous-fueled HDDEs, and that the crankcase emission provisions for all other classes of gaseous-fueled vehicles will take effect with the 1997 model year mandatory certification, as well as for vehicles and engines certified optionally prior to the 1997 model year. E. On-Board Diagnostics Summary of the proposal: EPA did not specifically address in the November 5, 1992 proposal the applicability of on-board diagnostics (OBD) requirements to gaseous-fueled vehicles. This is because the OBD regulations were not promulgated until after the gaseous-fueled vehicle standards were proposed.\17\ However, EPA proposed that emission standards for gaseous-fueled vehicles generally be equivalent to those for other vehicles. Implicit in that proposal is that gaseous-fueled vehicles would be required to meet the same OBD requirements as other vehicles (OBD II or Federal OBD, as applicable by model year). --------------------------------------------------------------------------- \17\58 FR 9468, February 19, 1993. --------------------------------------------------------------------------- Summary of the comments: The Agency received several comments concerning OBD. These comments fell into two general areas. First, several commenters requested that the Agency clarify the applicability of OBD requirements to gaseous-fueled vehicles. Second, comments were received stating that additional leadtime should be allowed for natural gas-fueled vehicles to comply with OBD. The OBD provisions as promulgated require OBD systems to monitor for conditions which would result in certain increases in THC emissions. The argument for additional leadtime centered around the fact that natural gas vehicles will only be subject to NMHC standards while all other vehicles are subject to THC standards. During the course of the OBD rulemaking comments were received suggesting that natural gas systems only be required to measure NMHC emission effects. Commenters argued that the technology likely to be used to monitor for increases in THC could not be readily adapted to monitor for increases in NMHC. The Agency received a comment suggesting that a delay until 1998 would allow sufficient leadtime to develop the technology needed for natural gas- fueled vehicles to meet the OBD requirements. EPA response to comments: The OBD requirements contained in the February 19, 1993 rule were established pursuant to section 202(m) of the Clean Air Act. That subsection provides, in pertinent part: (1) [T]he Administrator shall promulgate regulations under subsection (a) requiring manufacturers to install on all new light duty vehicles and light duty trucks diagnostic systems capable of-- (A) accurately identifying * * * emission-related systems deterioration or malfunction * * * which could cause or result in failure of the vehicles to comply with emission standards established under this section. By its terms, the OBD provision applies only to vehicles for which emission standards have been established under section 202. The regulations promulgated on February 19, 1993 simply add a new requirement that all new light-duty vehicles and light-duty trucks be equipped with an emission control diagnostic system capable of identifying emissions-related deterioration and malfunction as detailed in the regulations.\18\ Therefore, this provision would seem to apply automatically to gaseous-fueled vehicles as soon as mandatory emissions standards are established for those vehicles. --------------------------------------------------------------------------- \18\58 FR at 9485; 40 CFR 86.094-17. --------------------------------------------------------------------------- EPA agrees that leadtime until the 1998 model year is necessary for full implementation of the Federal OBD requirements for natural gas- fueled vehicles. Therefore, under today's regulations, implementation of Federal OBD systems will not be required for certification prior to model year 1998. This is the case for both for voluntary certification prior to model year 1997, and for mandatory certification in model year 1997. However, consistent with the approach taken in the OBD rule for vehicles granted a waiver from Federal OBD requirements on feasibility grounds, natural gas-fueled vehicles certified in the 1997 model year or optionally prior to the 1997 model year will be required to comply with OBD I provisions. EPA believes that allowing leadtime for natural gas-fueled vehicles until the 1998 model year is legally consistent with sections 202(m) and 202(a). To be sure, section 202(m)(2) specifically provides that the required OBD regulations shall take effect in model year 1994, subject to the Administrator's authority to waiver application of the regulations for model years 1994 and/or 1995 for any vehicle for which the Administrator determines the regulations would be infeasible in those model years. But EPA believes that Congress intended this effective date provision to apply only to vehicles for which standards existed at the time of the enactment of the Clean Air Act Amendments of 1990. EPA does not believe that Congress intended this provision to require OBD to be implemented immediately upon promulgation of any emission standards under section 202(a)(1) for new kinds of alternative-fueled vehicles at any point after 1995. EPA cannot adopt new emission standards for natural gas-fueled vehicles that would trigger a mandatory OBD requirement that is not feasible. It is also unreasonable to believe Congress intended that EPA refrain from establishing mandatory emission standards for natural gas-fueled vehicles simply because an infeasible OBD requirement would automatically apply once such standards are established. The Agency's efforts to ensure that natural gas fueled vehicles' emissions are no greater than their petroleum-fueled counterparts should not be frustrated by a concern that compliance with an OBD requirement requires more leadtime than compliance with the emission standards themselves. Rather, EPA believes that the OBD requirements under section 202(m)(1), to be promulgated under section 202(a), incorporate the general leadtime provision in section 202(a)(2). Section 202(a)(2) specifically states that ``[a]ny regulation prescribed under paragraph (1) of this subsection (and any revision thereof) shall take effect after such period as the Administrator finds necessary to permit the development and application of the requisite technology, giving appropriate consideration to the cost of compliance within such period.'' EPA believes that this leadtime provision applies to all aspects of new standards established with respect to previously unregulated alternative-fueled vehicles. EPA agrees with commenters that leadtime until model year 1998 is necessary for implementation of Federal OBD systems for natural gas-fueled vehicles. Therefore, Federal OBD requirements will not apply for certification of such vehicles until model year 1998; compliance with OBD I provisions is required for any natural gas-fueled vehicles certified prior to the 1998 model year, as discussed above. EPA also recognizes that the current OBD regulations apply to vehicles subject to a THC standard. As long as only a NMHC standard applies to natural gas-fueled vehicles, these regulations should arguably be amended to monitor deterioration and malfunction regarding NMHC emissions performance. EPA anticipates commencing a rulemaking to make these changes to the OBD regulations as applicable to natural gas- fueled vehicles in the near future in time for the changes to apply in the 1998 model year. This issue does not effect the feasibility of compliance with OBD I requirements. As was noted above, the Agency did not formally propose any specific requirements concerning the applicability of OBD requirements to gaseous-fueled vehicles. However, the Agency believes that this issue was fairly raised and sufficiently considered prior to the promulgation of this final rule since EPA's initial proposal intended to extend all applicable emission standards to gaseous-fueled vehicles, and the Agency received several comments on OBD in response to that proposal. For more discussion of this issue please consult the summary and analysis document. F. HC Measurement Summary of the proposal: The current method for measuring exhaust NMHC, which was adopted for the Tier 1 tailpipe standards, involves measuring THC and methane, and subtracting methane from THC to obtain NMHC. For NGVs the exhaust HC is primarily methane, whereas for other vehicles the exhaust methane tends to be a much lower percentage of THC. As a result, the current procedure is much less accurate for NGVs than for other vehicles, and the need for a better measurement technique is obvious. The NPRM discussed several potential options for improved, direct NMHC measurement. However, none of these techniques was developed sufficiently enough to warrant proposal. Thus, the Agency proposed, as an interim procedure, some slight modifications to the current procedure to improve its accuracy for NGVs. Additionally, EPA proposed that if a better technique had not been developed within the first two years of these standards' applicability then full gas chromatograph (GC) analysis would be required. This was intended to provide the industry with incentive to develop a better alternative since the inaccuracies of the current procedure clearly preclude it from being a long term solution. Summary of the comments: EPA received little comment on this aspect of the proposal. A few commenters voiced support for the interim procedure, while some expressed concern over how resource-intensive full GC analysis would be for routine certification work. EPA response to comments: The Agency agrees with the commenters that the modifications to the current procedure constitute the best interim option, and this is the technique that is contained in today's rule. Additionally, EPA has entered into a Cooperative Research and Development Agreement (CRADA) with the California Air Resources Board and the American Automobile Manufacturers Association to address a variety of test procedures needs which have arisen out of the Clean Air Act Amendments. One of the projects the CRADA is addressing is that of an accurate technique for the direct measurement of NMHC. The Agency believes that since it is participating in the development process through the CRADA a technology-forcing approach is not necessary at this time. Thus, rather than finalize a requirement for full GC analysis, the best approach would be to continue to work through the CRADA to develop an NMHC technique which can be adopted as the certification procedure upon its completion. However, if an appropriate technique is not developed through the CRADA, EPA will consider a more accurate procedure such as the GC for the required procedure. G. Fuel Composition Summary of the proposal: It is the Agency's belief that certification test fuels should resemble the fuels that a vehicle is likely to encounter in-use. Given the wide range of natural gas compositions currently available throughout the United States, the Agency proposed very broad specifications for natural gas certification fuel. These specifications included a range for methane content of 74 to 98.5 percent, as well as broad ranges for several other parameters. In the case of LPG fuel, much less information is available about composition variability nationally. Thus, commercially available LPG was proposed as the certification fuel, with no specific ranges set on any parameters other than that the primary constituent be propane. The NPRM contained no provisions for the regulation of in-use composition of either fuel. Summary of the comments: Although the Agency received some comments in support of its proposed certification fuel specifications, in general commenters believed that the proposed specifications were much too broad. In terms of natural gas specifications, the comments in favor of tighter specifications fell into two general categories. First, several commenters stated that they agreed with EPA's general approach of a broadly defined specification in order that certification fuel be representative of in-use fuel. These commenters, however, felt that the proposed fuel specification was much too broad and encompassed fuels which could not be considered representative of most natural gas. Other commenters felt that, in order to be able to meaningfully compare results from different tests, a very narrowly defined test fuel specification is needed. Most of these commenters recommended that EPA adopt the California Air Resources Board (CARB) certification fuel (90% methane, 1%, among other requirements) as the federal certification fuel. Some of the commenters who recommended a narrower range of specifications suggested that EPA adopt a range of specifications which would allow the use of CARB certification fuel (e.g., 89% methane, minimum, etc.). The Agency received little comment on the proposed LPG certification fuel specifications. A few commenters suggested that EPA adopt the CARB LPG certification fuel specifications (93.5% propane, 1%, etc.) as the federal certification fuel. Some commenters agreed with the proposal, stating that it allowed for the use of butane mixtures in LPG vehicles. In addition to comments about certification fuel specifications, several comments were received requesting that the Agency adopt in-use fuel specifications. These comments generally came from engine and vehicle manufacturers. These commenters explained that in order to get maximum emission benefits from gaseous-fueled vehicles it is important to minimize in-use fuel composition variability. In addition, heavy- duty diesel engine manufacturers stated that, unlike stoichiometric engines utilizing oxygen sensor feedback control systems, lean-burn diesel engines have no way of accounting for fuel composition variability, and thus may encounter operational difficulties on some fuels. EPA response to comments: The Agency both understands and sees the merits in the arguments for tighter certification fuel specifications. However, as was previously stated, EPA also believes it is important that certification fuel be representative of in-use fuel. Thus, in developing today's final rule the Agency has attempted to find a middle ground between these seemingly conflicting needs. In the case of natural gas certification fuel, the Agency is adopting the approach suggested by some commenters that the specification remain somewhat broad, but allow for the use of CARB certification fuel. This specification includes a minimum methane content of 89 percent, among other parameters. For the complete certification fuel specifications please see the regulatory text of today's rule. These specifications were chosen both because they encompass over 90 percent of natural gas sold in the country and because there was some general support for them in the comments as a good compromise between EPA's proposed specifications and CARB certification fuel. Almost all of the gas not covered by this specification (i.e., gas with a methane content below 89 percent) is sold in high altitude areas where the gas tends to contain higher levels of inert gases than that sold at low altitudes. The Agency believes that excluding high altitude gas from the specifications should not present a problem for vehicles which are certified using the 89 percent minimum methane certification fuel but are operated at high altitudes because, in general, vehicles which will be certified under the provisions of today's rule are expected to utilize electronic feedback control systems for proper management of the fuel/air ratio. The Agency believes that these systems will be able to account for any differences in fuel composition between high altitude natural gas and natural gas in the rest of the country. It should be noted that, while the natural gas certification fuel specifications contained in today's rule are much broader than CARB's, CARB certification fuel does fall within the federal specifications, and thus could be used for certification testing. For a further discussion of this issue please consult the summary and analysis of comments document available in the public docket. The Agency would like to take a similar approach for LPG certification fuel as it took for natural gas certification fuel. However, there is little information available about in-use LPG composition upon which such a fuel specification could be based. Thus, EPA believes it prudent to adopt commercial LPG as the certification fuel at this time. Should adequate information on in-use LPG composition become available at some point in the future, EPA may elect to define a certification fuel specification for LPG at that time. Today's rule contains no controls on in-use fuel composition for either natural gas or LPG. EPA does not believe that the need for such in-use controls has been adequately demonstrated. Further, the cost- effectiveness of such controls is not likely to justify such action. The Agency is concerned, however, about the possibility of in-use fuel composition changes over time, and urges the natural gas and LPG industries to take steps to minimize such variations. Should the in-use compositions of these fuels change in such a way as to adversely impact the emissions performance of gaseous-fueled vehicles the Agency would likely take steps to address the issue at that time, either through corresponding changes in certification fuel specifications, or possibly through in-use fuel composition specifications. H. Fuel Economy Summary of the proposal: The NPRM included test procedures and calculations for determining the fuel economy of natural gas-fueled light-duty vehicles and light-duty trucks for purposes of allowing them to be included in a manufacturer's CAFE calculation. The proposed procedures for determining the fuel economy of natural gas vehicles (NGV) utilize the same principles as those used in the procedures currently in place for gasoline vehicles. Availability of CAFE credits for NGVs was mandated in the Alternative Motor Fuels Act (AMFA) of 1988 (Public Law 100-494, October 14, 1988), to be effective with the 1993 model year. No CAFE provisions regarding LPG vehicles were proposed. Summary of the comments: In general, the comments regarding the CAFE provisions for NGVs were very supportive. Some commenters urged EPA to quickly finalize this rule in order to assure that CAFE credits will be available for 1993 model year NGVs. The lack of fuel economy provisions for LPG vehicles, however, was perceived by many as an unfair disadvantage for LPG vehicles. Additionally, many commenters pointed out that the National Energy Policy Act of 1992 mandated the availability of CAFE credits for LPG vehicles, and urged EPA to finalize fuel economy test procedures and calculations for LPG vehicles. EPA response to comments: The Agency did not propose fuel economy measurement procedures for LPG vehicles because prior to the National Energy Policy Act of 1992 the determination of whether LPG vehicles should be included in the CAFE program was required to be made by the Secretary of Transportation under the Energy Policy and Conservation Act (U.S.C. 2001(5)). At the time EPA issued the NPRM for today's action the Secretary of Transportation had not made a determination to include LPG vehicles in the CAFE program. The Energy Policy Act allowing LPG vehicles to participate in the CAFE program was signed into law just as EPA issued its proposal. Thus, no fuel economy provisions were proposed for LPG vehicles. There are two reasons why EPA is not adopting fuel economy provisions for LPG vehicles in this rule. First, before EPA can adopt fuel economy test procedures and calculations for LPG vehicles, the U.S. Department of Transportation (DOT) is required by the Energy Policy Act to determine a fuel equivalency factor equating gasoline and LPG so that fuel economy can be calculated on a gasoline gallon- equivalent basis. This fuel equivalency factor has not yet been set by DOT. Second, the Agency believes that the required new fuel economy measurement provisions for LPG vehicles must be subject to public notice and comment. Thus, the Agency will work with DOT to develop the fuel equivalency factor, and, upon determination of that factor, will propose LPG fuel economy provisions in a separate Agency rulemaking action. I. Aftermarket Conversions 1. Applicability Summary of the proposal: It is the Agency's policy that, based on the tampering provisions of section 203(a)(3) of the Act, aftermarket conversions should not degrade the emissions performance of the vehicle being converted, and that following a conversion a vehicle should still meet the emission standards it was originally certified as meeting on any fuels it is capable of using. Under this policy any conversion which degrades the emissions performance of the vehicle is considered tampering. In order to clarify how compliance with this policy can be demonstrated, the Agency proposed that converters can certify as new vehicle manufacturers using the current new vehicle certification procedures applicable to small volume manufacturers. The Agency requested comment on whether the volume limit of 10,000 units that currently defines a small volume manufacturer should apply to conversions as well, or whether, as proposed, the small volume procedures should apply to all converters, regardless of the conversion sales volume of the company seeking the certification. These certification requirements were proposed to apply to all aftermarket conversions performed or sold after December 31, 1993, regardless of the class or model year of the vehicle being converted. In the proposal the Agency stated its belief that this rule would not require any leadtime for technology development and that the only leadtime required would be for the actual certification process. Summary of the comments: In general, the comments received on the aftermarket conversion provisions were very supportive, with several commenters expressing the need for such requirements, and none completely opposed. One commenter suggested that these requirements should only apply to conversions in areas which are not in attainment with national ambient air quality standards. Comments were received both in favor of and opposed to applying the 10,000 limit to the use of the small volume procedures for conversions. Other comments received indicated that there was some confusion as to the applicability of the proposed requirements to conversions done before 1994, as well as to conversions of pre-1994 model year vehicles performed after December 31, 1993. EPA response to comments: As was stated in the description of today's rule, an aftermarket conversion company can choose to comply with these provisions to obtain an exemption from the tampering prohibition. Only conversions which are intended to generate some form of credit, such as clean-fueled fleet vehicle purchase credits, will be required to comply with these provisions. Converters which choose not to obtain an exemption from the tampering prohibition under this procedure will be handled under the current tampering policy. Given that this is an optional certification procedure for conversions the issues of leadtime and mandatory start date are less relevant. The Agency agrees with the comment that the production volume limits that currently define a small volume manufacturer also apply to converters seeking to certify as manufacturers under today's program. The Agency expects that the demand for aftermarket conversions will grow dramatically over the next few years in response to a variety of state and federal programs. It seems reasonable to require the larger conversion companies to undergo full new vehicle certification if they choose to get an exemption from the tampering prohibition by certifying as a manufacturer. Thus, the volume limits that currently apply to manufacturers seeking to certify under the small volume manufacturers provisions will also apply to converters seeking to certify as manufacturers. The Agency recognizes that, while the current small volume manufacturers limit applies to sales for a particular model year, conversions are routinely performed on older vehicles, and a conversion company may offer conversion systems for vehicles from several different model years at any given time. Thus, the 10,000 sales volume limit for certifying under the small volume manufacturers procedures will apply to calendar year sales for the purposes of aftermarket conversions. For a further discussion of how this volume limit will be applied see the summary and analysis of comments document. 2. Test Procedures Summary of the proposal: In the NPRM the Agency proposed using the same test procedures for conversions that are used for new vehicle and engine certification. This approach was proposed because the Agency believes that this is the only way of truly measuring the emissions performance of a conversion relative to the emission standards applicable to the original vehicle or engine. Summary of the comments: Most of the comments received on the issue of test procedures for aftermarket conversions concerned the differences between EPA's proposed procedures and those adopted by CARB. In general, where there are differences between CARB's procedures and those proposed by EPA the commenters requested that the Agency adopt the CARB procedures instead of what it proposed. In the case of procedures for converted light-duty vehicles and light-duty trucks EPA's proposed test procedures are essentially the same as CARB's. Thus, there is no issue in the case of light-duty vehicle and light- duty truck certification procedures for aftermarket conversions. EPA's proposed procedures for conversions of vehicles whose engines were originally certified on an engine dynamometer (i.e., most heavy- duty engines) are quite different than CARB's. As was previously mentioned, the Agency proposed that conversions in this category be certified using the test procedure used to certify the original engine. That procedure is the engine dynamometer-based heavy-duty transient test. CARB's procedures use the chassis dynamometer-based urban dynamometer driving cycle for conversions of vehicles 14,000 pounds and under gross vehicle weight (GVW). For conversions of vehicles greater than 14,000 pounds GVW, CARB's procedures allow for either steady-state chassis dynamometer testing or an engine dynamometer test approved by the CARB Executive Officer. Most of the comments received on this issue requested that, in order to reduce compliance costs, EPA adopt the CARB test procedures for aftermarket conversions. One commenter also suggested that it is unfair to require conversions for heavy-duty engines to be certified using the heavy-duty transient test because there are few available testing facilities at which one could get the required testing done. EPA response to comments: The Agency continues to believe that the most appropriate way to determine whether an aftermarket conversion meets the emission standards that the original vehicle or engine was certified to is to use the same test procedures that were used in certifying the original vehicle or engine. As the comments suggest, this is only an issue for the conversions intended for vehicles originally certified using the engine dynamometer procedures. While the Agency understands the concerns voiced by the commenters, it does not believe that there is an adequate alternative to using the original test procedures when attempting to demonstrate compliance with the original standards. In the case of the CARB procedures, CARB uses an approach whereby compliance is determined by comparing post-conversion emissions performance with pre-conversion performance, and allowing for some increase in emissions to account for test to test variability. Given this approach, it is not nearly as important for CARB to use the same test procedures that were used to certify the original vehicle because the standards being certified to are not those the vehicle was originally certified as meeting. However, by taking this approach it is possible that an aftermarket conversion which exceeds the original configuration's emissions standards could be certified, which is in conflict with the anti-tampering provisions of the Act. In the case of vehicles over 14,000 pounds GVW, CARB allows the use of eight mode steady-state testing, using the same pre-conversion, post-conversion comparison as for vehicles under 14,000 pounds GVW. Again, the Agency believes that it is possible with this approach to certify an aftermarket conversion which exceeds the original configuration's emissions standards. Also, the Agency does not believe that steady-state testing is appropriate under any circumstances. It is well-understood that emission control systems can be designed for low emissions when tested using steady-state test procedures, but provide little emissions control under real-world, transient conditions.\19\ It is for this reason that EPA adopted the heavy-duty transient test cycle in place of the thirteen mode steady state test for all heavy-duty engine certification, effective in the mid-1980s. Thus, EPA does not believe that it would be appropriate to adopt the CARB test procedures for these vehicles. It should be noted that CARB does allow for alternative test cycles for vehicles over 14,000 pounds GVW, subject to advance approval from the Executive Officer. It is the Agency's belief that, given the transient test is the test cycle which these vehicles would have originally been certified on, it is likely that CARB would approve its use for conversion certification, thus eliminating the need for two separate certification procedures for vehicles over 14,000 pounds GVW. --------------------------------------------------------------------------- \19\45 FR 4136, January 21, 1980. --------------------------------------------------------------------------- 3. On-Board Diagnostics Summary of the proposal: The Agency recently adopted requirements, effective for the 1994 model year and thereafter, which require on- board diagnostics (OBD) systems on new light-duty vehicles and light- duty trucks.\20\ The purpose of the OBD system is, in part, to monitor the performance of a vehicle's emission control systems and signal to the vehicle operator if a system is malfunctioning. The Agency did not propose any specific requirements regarding how aftermarket conversions would interact with new vehicle OBD systems, but required that converted vehicles remain in compliance with all applicable Clean Air Act Title II emission requirements. --------------------------------------------------------------------------- \20\58 FR 9468, February 19, 1993. --------------------------------------------------------------------------- Summary of the comments: The Agency only received a few comments on the issue of aftermarket conversions and OBD. These comments tended not to be specific, but rather asked the Agency to clarify what the requirements were for an aftermarket conversion on an OBD-equipped vehicle. A few commenters suggested that EPA require new vehicle manufacturers to provide some means of shutting off the OBD system during alternative fuel operation in order to prevent the system from storing faulty trouble codes. EPA response to comments: As explained in the preamble to the proposed rule, EPA believes that a tampering exemption should be conditioned upon certification demonstrating that the converted vehicle has the ability to comply with the applicable emission standards and will have demonstrated adequate durability. As was mentioned above, shortly after publication of the proposal for this rule, the Agency adopted requirements, effective for the 1994 model year, which require OBD systems on new light-duty vehicles and light-duty trucks. While the aftermarket conversions proposal did not explicitly make clear that compliance with the OBD requirements (as well as certain other title II requirements) must be demonstrated to obtain a certification, the Agency believes this is implicit in the discussion of the justification for the exemption. The Agency explained in the proposal that ``Congress intended to prohibit tampering that would result in emission noncompliance,'' and that ``[t]he language of the tampering provisions emphasizes the compliance of the vehicle with the title II regulations.'' EPA's justification for the exemption for conversions from tampering restrictions was based on the incongruity of prohibiting conversions that result in a vehicle meeting emission standards applicable to vehicles of the fuel type to which the vehicles have been converted. The OBD requirements, even if not ``emissions standards'' in the traditional sense, clearly have an underlying emissions control purpose. And the tampering prohibitions of section 203(a)(3) of the Act explicitly apply to the disabling of any device ``installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title. . .'' Disabling an OBD system is clearly prohibited as tampering. It is therefore not at all clear that EPA would have authority to provide an exemption from the tampering prohibition for a conversion that do not meet the same OBD requirements as the vehicle would have had to meet had it been originally manufactured to operate on fuel type to which it has been converted. The logic of the Agency's tampering exemption for aftermarket conversions thus indicates that the Agency intended that the exemption be conditioned on compliance with all title II requirements applicable to the converted vehicle when operating on either fuel. Certainly, even if the proposal did not specifically make clear that it intended to require compliance with OBD as a condition for a tampering exemption, that requirement is a logical outgrowth of the discussion in the proposal. The comments of interested parties reflect a recognition of EPA's authority to require compliance with OBD as a condition of the tampering exemption. These comments demonstrate the adequacy of notice.\21\ --------------------------------------------------------------------------- \21\See Shell Oil Co. v. EPA, 950 F.2nd 741, (Dec. 6, 1991). --------------------------------------------------------------------------- 4. Liability Summary of the proposal: In the NPRM the Agency proposed that, in order to be exempt from the Clean Air Act's tampering prohibition, the manufacturers and installers of aftermarket conversions must accept in- use liability for warranty and recall as outlined in section 207 of the Act and its implementing regulations.\22\ Additionally, EPA proposed that the vehicle's original manufacturer remain liable for the in-use performance of any systems which retain their original purpose following conversion, except in cases where the failure of such a system is determined to be caused by the conversion. The Agency proposed that the useful life of a conversion be the same as that of the vehicle being converted, and requested comment on whether the useful life of the conversion should be measured from the time of the conversion or from the time of the original vehicle's manufacture. --------------------------------------------------------------------------- \22\40 CFR Part 85. --------------------------------------------------------------------------- Summary of the comments: The Agency received a variety of comments on the proposed liability scheme. In general, commenters agreed on the need for in-use liability for warranty and recall, but differed on where or with whom this liability should be placed. Some commenters suggested that the primary liability should be with the conversion system manufacturer, and that the installer should only be held liable for the proper installation of the conversion system. Other commenters agreed with EPA's proposed liability suggesting both that this approach would protect the conversion consumer in the event that one party went out of business, and that it would allow manufacturers and installers to negotiate risk of failure between them. Comments received on the issue of liability of the vehicle's original manufacturer for the proper functioning of original equipment also supported both sides of the issue, with some commenters suggesting that the original manufacturer's liability should end at the time of conversion and others supporting the Agency's proposed approach. Finally, all comments received on the issue of when the useful life begins were in favor of reducing the useful life requirement of the conversion by the amount of the original vehicle's useful life which had already passed at the time of conversion. These commenters suggested that, because aftermarket conversions generally depend on the original vehicle equipment to some extent for emissions performance, it would not be appropriate to require the conversion to continue meeting applicable emission standards after the original equipment had exceeded its useful life. EPA response to the comments: The Agency believes that by holding the entity which certifies the conversion system liable for the in-use performance of the converted vehicle it has the greatest chance of assuring quality conversions which will meet applicable emission standards throughout their useful lives. If poor installation were a defense to liability, then certifiers would have no interest [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-22131. Public record. Not legal advice.