
From the U.S. Code Online via GPO Access
[wais.access.gpo.gov]
[Laws in effect as of January 23, 2000]
[Document not affected by Public Laws enacted between
  January 23, 2000 and December 4, 2001]
[CITE: 42USC7521]

 
                 TITLE 42--THE PUBLIC HEALTH AND WELFARE
 
            CHAPTER 85--AIR POLLUTION PREVENTION AND CONTROL
 
          SUBCHAPTER II--EMISSION STANDARDS FOR MOVING SOURCES
 
            Part A--Motor Vehicle Emission and Fuel Standards
 
Sec. 7521. Emission standards for new motor vehicles or new 
        motor vehicle engines
        

(a) Authority of Administrator to prescribe by regulation

    Except as otherwise provided in subsection (b) of this section--
    (1) The Administrator shall by regulation prescribe (and from time 
to time revise) in accordance with the provisions of this section, 
standards applicable to the emission of any air pollutant from any class 
or classes of new motor vehicles or new motor vehicle engines, which in 
his judgment cause, or contribute to, air pollution which may reasonably 
be anticipated to endanger public health or welfare. Such standards 
shall be applicable to such vehicles and engines for their useful life 
(as determined under subsection (d) of this section, relating to useful 
life of vehicles for purposes of certification), whether such vehicles 
and engines are designed as complete systems or incorporate devices to 
prevent or control such pollution.
    (2) Any 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.
    (3)(A) In general.--(i) Unless the standard is changed as provided 
in subparagraph (B), regulations under paragraph (1) of this subsection 
applicable to emissions of hydrocarbons, carbon monoxide, oxides of 
nitrogen, and particulate matter from classes or categories of heavy-
duty vehicles or engines manufactured during or after model year 1983 
shall contain standards which reflect the greatest degree of emission 
reduction achievable through the application of technology which the 
Administrator determines will be available for the model year to which 
such standards apply, giving appropriate consideration to cost, energy, 
and safety factors associated with the application of such technology.
    (ii) In establishing classes or categories of vehicles or engines 
for purposes of regulations under this paragraph, the Administrator may 
base such classes or categories on gross vehicle weight, horsepower, 
type of fuel used, or other appropriate factors.
    (B) Revised standards for heavy duty trucks.--(i) On the basis of 
information available to the Administrator concerning the effects of air 
pollutants emitted from heavy-duty vehicles or engines and from other 
sources of mobile source related pollutants on the public health and 
welfare, and taking costs into account, the Administrator may promulgate 
regulations under paragraph (1) of this subsection revising any standard 
promulgated under, or before the date of, the enactment of the Clean Air 
Act Amendments of 1990 (or previously revised under this subparagraph) 
and applicable to classes or categories of heavy-duty vehicles or 
engines.
    (ii) Effective for the model year 1998 and thereafter, the 
regulations under paragraph (1) of this subsection applicable to 
emissions of oxides of nitrogen (NO<INF>x</INF>) from gasoline and 
diesel-fueled heavy duty trucks shall contain standards which provide 
that such emissions may not exceed 4.0 grams per brake horsepower hour 
(gbh).
    (C) Lead time and stability.--Any standard promulgated or revised 
under this paragraph and applicable to classes or categories of heavy-
duty vehicles or engines shall apply for a period of no less than 3 
model years beginning no earlier than the model year commencing 4 years 
after such revised standard is promulgated.
    (D) Rebuilding practices.--The Administrator shall study the 
practice of rebuilding heavy-duty engines and the impact rebuilding has 
on engine emissions. On the basis of that study and other information 
available to the Administrator, the Administrator may prescribe 
requirements to control rebuilding practices, including standards 
applicable to emissions from any rebuilt heavy-duty engines (whether or 
not the engine is past its statutory useful life), which in the 
Administrator's judgment cause, or contribute to, air pollution which 
may reasonably be anticipated to endanger public health or welfare 
taking costs into account. Any regulation shall take effect after a 
period the Administrator finds necessary to permit the development and 
application of the requisite control measures, giving appropriate 
consideration to the cost of compliance within the period and energy and 
safety factors.
    (E) Motorcycles.--For purposes of this paragraph, motorcycles and 
motorcycle engines shall be treated in the same manner as heavy-duty 
vehicles and engines (except as otherwise permitted under section 
7525(f)(1) \1\ of this title) unless the Administrator promulgates a 
rule reclassifying motorcycles as light-duty vehicles within the meaning 
of this section or unless the Administrator promulgates regulations 
under subsection (a) of this section applying standards applicable to 
the emission of air pollutants from motorcycles as a separate class or 
category. In any case in which such standards are promulgated for such 
emissions from motorcycles as a separate class or category, the 
Administrator, in promulgating such standards, shall consider the need 
to achieve equivalency of emission reductions between motorcycles and 
other motor vehicles to the maximum extent practicable.
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    \1\ See References in Text note below.
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    (4)(A) Effective with respect to vehicles and engines manufactured 
after model year 1978, no emission control device, system, or element of 
design shall be used in a new motor vehicle or new motor vehicle engine 
for purposes of complying with requirements prescribed under this 
subchapter if such device, system, or element of design will cause or 
contribute to an unreasonable risk to public health, welfare, or safety 
in its operation or function.
    (B) In determining whether an unreasonable risk exists under 
subparagraph (A), the Administrator shall consider, among other factors, 
(i) whether and to what extent the use of any device, system, or element 
of design causes, increases, reduces, or eliminates emissions of any 
unregulated pollutants; (ii) available methods for reducing or 
eliminating any risk to public health, welfare, or safety which may be 
associated with the use of such device, system, or element of design, 
and (iii) the availability of other devices, systems, or elements of 
design which may be used to conform to requirements prescribed under 
this subchapter without causing or contributing to such unreasonable 
risk. The Administrator shall include in the consideration required by 
this paragraph all relevant information developed pursuant to section 
7548 of this title.
    (5)(A) If the Administrator promulgates final regulations which 
define the degree of control required and the test procedures by which 
compliance could be determined for gasoline vapor recovery of 
uncontrolled emissions from the fueling of motor vehicles, the 
Administrator shall, after consultation with the Secretary of 
Transportation with respect to motor vehicle safety, prescribe, by 
regulation, fill pipe standards for new motor vehicles in order to 
insure effective connection between such fill pipe and any vapor 
recovery system which the Administrator determines may be required to 
comply with such vapor recovery regulations. In promulgating such 
standards the Administrator shall take into consideration limits on fill 
pipe diameter, minimum design criteria for nozzle retainer lips, limits 
on the location of the unleaded fuel restrictors, a minimum access zone 
surrounding a fill pipe, a minimum pipe or nozzle insertion angle, and 
such other factors as he deems pertinent.
    (B) Regulations prescribing standards under subparagraph (A) shall 
not become effective until the introduction of the model year for which 
it would be feasible to implement such standards, taking into 
consideration the restraints of an adequate leadtime for design and 
production.
    (C) Nothing in subparagraph (A) shall (i) prevent the Administrator 
from specifying different nozzle and fill neck sizes for gasoline with 
additives and gasoline without additives or (ii) permit the 
Administrator to require a specific location, configuration, modeling, 
or styling of the motor vehicle body with respect to the fuel tank fill 
neck or fill nozzle clearance envelope.
    (D) For the purpose of this paragraph, the term ``fill pipe'' shall 
include the fuel tank fill pipe, fill neck, fill inlet, and closure.
    (6) Onboard vapor recovery.--Within 1 year after November 15, 1990, 
the Administrator shall, after consultation with the Secretary of 
Transportation regarding the safety of vehicle-based (``onboard'') 
systems for the control of vehicle refueling emissions, promulgate 
standards under this section requiring that new light-duty vehicles 
manufactured beginning in the fourth model year after the model year in 
which the standards are promulgated and thereafter shall be equipped 
with such systems. The standards required under this paragraph shall 
apply to a percentage of each manufacturer's fleet of new light-duty 
vehicles beginning with the fourth model year after the model year in 
which the standards are promulgated. The percentage shall be as 
specified in the following table:

     Implementation Schedule for Onboard Vapor Recovery Requirements
------------------------------------------------------------------------
  Model year commencing after  standards
               promulgated                          Percentage*
------------------------------------------------------------------------
Fourth...................................                40
Fifth....................................                80
After Fifth..............................               100
------------------------------------------------------------------------
*Percentages in the table refer to a percentage of the manufacturer's
  sales volume.

The standards shall require that such systems provide a minimum 
evaporative emission capture efficiency of 95 percent. The requirements 
of section 7511a(b)(3) of this title (relating to stage II gasoline 
vapor recovery) for areas classified under section 7511 of this title as 
moderate for ozone shall not apply after promulgation of such standards 
and the Administrator may, by rule, revise or waive the application of 
the requirements of such section 7511a(b)(3) of this title for areas 
classified under section 7511 of this title as Serious, Severe, or 
Extreme for ozone, as appropriate, after such time as the Administrator 
determines that onboard emissions control systems required under this 
paragraph are in widespread use throughout the motor vehicle fleet.

(b) Emissions of carbon monoxide, hydrocarbons, and oxides of nitrogen; 
        annual report to Congress; waiver of emission standards; 
        research objectives

    (1)(A) The regulations under subsection (a) of this section 
applicable to emissions of carbon monoxide and hydrocarbons from light-
duty vehicles and engines manufactured during model years 1977 through 
1979 shall contain standards which provide that such emissions from such 
vehicles and engines may not exceed 1.5 grams per vehicle mile of 
hydrocarbons and 15.0 grams per vehicle mile of carbon monoxide. The 
regulations under subsection (a) of this section applicable to emissions 
of carbon monoxide from light-duty vehicles and engines manufactured 
during the model year 1980 shall contain standards which provide that 
such emissions may not exceed 7.0 grams per vehicle mile. The 
regulations under subsection (a) of this section applicable to emissions 
of hydrocarbons from light-duty vehicles and engines manufactured during 
or after model year 1980 shall contain standards which require a 
reduction of at least 90 percent from emissions of such pollutant 
allowable under the standards under this section applicable to light-
duty vehicles and engines manufactured in model year 1970. Unless waived 
as provided in paragraph (5), regulations under subsection (a) of this 
section applicable to emissions of carbon monoxide from light-duty 
vehicles and engines manufactured during or after the model year 1981 
shall contain standards which require a reduction of at least 90 percent 
from emissions of such pollutant allowable under the standards under 
this section applicable to light-duty vehicles and engines manufactured 
in model year 1970.
    (B) The regulations under subsection (a) of this section applicable 
to emissions of oxides of nitrogen from light-duty vehicles and engines 
manufactured during model years 1977 through 1980 shall contain 
standards which provide that such emissions from such vehicles and 
engines may not exceed 2.0 grams per vehicle mile. The regulations under 
subsection (a) of this section applicable to emissions of oxides of 
nitrogen from light-duty vehicles and engines manufactured during the 
model year 1981 and thereafter shall contain standards which provide 
that such emissions from such vehicles and engines may not exceed 1.0 
gram per vehicle mile. The Administrator shall prescribe standards in 
lieu of those required by the preceding sentence, which provide that 
emissions of oxides of nitrogen may not exceed 2.0 grams per vehicle 
mile for any light-duty vehicle manufactured during model years 1981 and 
1982 by any manufacturer whose production, by corporate identity, for 
calendar year 1976 was less than three hundred thousand light-duty motor 
vehicles worldwide if the Administrator determines that--
        (i) the ability of such manufacturer to meet emission standards 
    in the 1975 and subsequent model years was, and is, primarily 
    dependent upon technology developed by other manufacturers and 
    purchased from such manufacturers; and
        (ii) such manufacturer lacks the financial resources and 
    technological ability to develop such technology.

    (C) The Administrator may promulgate regulations under subsection 
(a)(1) of this section revising any standard prescribed or previously 
revised under this subsection, as needed to protect public health or 
welfare, taking costs, energy, and safety into account. Any revised 
standard shall require a reduction of emissions from the standard that 
was previously applicable. Any such revision under this subchapter may 
provide for a phase-in of the standard. It is the intent of Congress 
that the numerical emission standards specified in subsections 
(a)(3)(B)(ii), (g), (h), and (i) of this section shall not be modified 
by the Administrator after November 15, 1990, for any model year before 
the model year 2004.
    (2) Emission standards under paragraph (1), and measurement 
techniques on which such standards are based (if not promulgated prior 
to November 15, 1990), shall be promulgated by regulation within 180 
days after November 15, 1990.
    (3) For purposes of this part--
        (A)(i) The term ``model year'' with reference to any specific 
    calendar year means the manufacturer's annual production period (as 
    determined by the Administrator) which includes January 1 of such 
    calendar year. If the manufacturer has no annual production period, 
    the term ``model year'' shall mean the calendar year.
        (ii) For the purpose of assuring that vehicles and engines 
    manufactured before the beginning of a model year were not 
    manufactured for purposes of circumventing the effective date of a 
    standard required to be prescribed by subsection (b) of this 
    section, the Administrator may prescribe regulations defining 
    ``model year'' otherwise than as provided in clause (i).
        (B) Repealed. Pub. L. 101-549, title II, Sec. 230(1), Nov. 15, 
    1990, 104 Stat. 2529.
        (C) The term ``heavy duty vehicle'' means a truck, bus, or other 
    vehicle manufactured primarily for use on the public streets, roads, 
    and highways (not including any vehicle operated exclusively on a 
    rail or rails) which has a gross vehicle weight (as determined under 
    regulations promulgated by the Administrator) in excess of six 
    thousand pounds. Such term includes any such vehicle which has 
    special features enabling off-street or off-highway operation and 
    use.

    (3) \2\ Upon the petition of any manufacturer, the Administrator, 
after notice and opportunity for public hearing, may waive the standard 
required under subparagraph (B) of paragraph (1) to not exceed 1.5 grams 
of oxides of nitrogen per vehicle mile for any class or category of 
light-duty vehicles or engines manufactured by such manufacturer during 
any period of up to four model years beginning after the model year 1980 
if the manufacturer demonstrates that such waiver is necessary to permit 
the use of an innovative power train technology, or innovative emission 
control device or system, in such class or category of vehicles or 
engines and that such technology or system was not utilized by more than 
1 percent of the light-duty vehicles sold in the United States in the 
1975 model year. Such waiver may be granted only if the Administrator 
determines--
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    \2\ So in original. Probably should be ``(4)''.
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        (A) that such waiver would not endanger public health,
        (B) that there is a substantial likelihood that the vehicles or 
    engines will be able to comply with the applicable standard under 
    this section at the expiration of the waiver, and
        (C) that the technology or system has a potential for long-term 
    air quality benefit and has the potential to meet or exceed the 
    average fuel economy standard applicable under the Energy Policy and 
    Conservation Act [42 U.S.C. 6201 et seq.] upon the expiration of the 
    waiver.

No waiver under this subparagraph \3\ granted to any manufacturer shall 
apply to more than 5 percent of such manufacturer's production or more 
than fifty thousand vehicles or engines, whichever is greater.
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    \3\ So in original. Probably should be ``paragraph''.
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(c) Feasibility study and investigation by National Academy of Sciences; 
        reports to Administrator and Congress; availability of 
        information

    (1) The Administrator shall undertake to enter into appropriate 
arrangements with the National Academy of Sciences to conduct a 
comprehensive study and investigation of the technological feasibility 
of meeting the emissions standards required to be prescribed by the 
Administrator by subsection (b) of this section.
    (2) Of the funds authorized to be appropriated to the Administrator 
by this chapter, such amounts as are required shall be available to 
carry out the study and investigation authorized by paragraph (1) of 
this subsection.
    (3) In entering into any arrangement with the National Academy of 
Sciences for conducting the study and investigation authorized by 
paragraph (1) of this subsection, the Administrator shall request the 
National Academy of Sciences to submit semiannual reports on the 
progress of its study and investigation to the Administrator and the 
Congress, beginning not later than July 1, 1971, and continuing until 
such study and investigation is completed.
    (4) The Administrator shall furnish to such Academy at its request 
any information which the Academy deems necessary for the purpose of 
conducting the investigation and study authorized by paragraph (1) of 
this subsection. For the purpose of furnishing such information, the 
Administrator may use any authority he has under this chapter (A) to 
obtain information from any person, and (B) to require such person to 
conduct such tests, keep such records, and make such reports respecting 
research or other activities conducted by such person as may be 
reasonably necessary to carry out this subsection.

(d) Useful life of vehicles

    The Administrator shall prescribe regulations under which the useful 
life of vehicles and engines shall be determined for purposes of 
subsection (a)(1) of this section and section 7541 of this title. Such 
regulations shall provide that except where a different useful life 
period is specified in this subchapter useful life shall--
        (1) in the case of light duty vehicles and light duty vehicle 
    engines and light-duty trucks up to 3,750 lbs. LVW and up to 6,000 
    lbs. GVWR, be a period of use of five years or fifty thousand miles 
    (or the equivalent), whichever first occurs, except that in the case 
    of any requirement of this section which first becomes applicable 
    after November 15, 1990, where the useful life period is not 
    otherwise specified for such vehicles and engines, the period shall 
    be 10 years or 100,000 miles (or the equivalent), whichever first 
    occurs, with testing for purposes of in-use compliance under section 
    7541 of this title up to (but not beyond) 7 years or 75,000 miles 
    (or the equivalent), whichever first occurs;
        (2) in the case of any other motor vehicle or motor vehicle 
    engine (other than motorcycles or motorcycle engines), be a period 
    of use set forth in paragraph (1) unless the Administrator 
    determines that a period of use of greater duration or mileage is 
    appropriate; and
        (3) in the case of any motorcycle or motorcycle engine, be a 
    period of use the Administrator shall determine.

(e) New power sources or propulsion systems

    In the event of a new power source or propulsion system for new 
motor vehicles or new motor vehicle engines is submitted for 
certification pursuant to section 7525(a) of this title, the 
Administrator may postpone certification until he has prescribed 
standards for any air pollutants emitted by such vehicle or engine which 
in his judgment cause, or contribute to, air pollution which may 
reasonably be anticipated to endanger the public health or welfare but 
for which standards have not been prescribed under subsection (a) of 
this section.

(f) \4\ High altitude regulations
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    \4\ Another subsec. (f) is set out after subsec. (m).
---------------------------------------------------------------------------
    (1) The high altitude regulation in effect with respect to model 
year 1977 motor vehicles shall not apply to the manufacture, 
distribution, or sale of 1978 and later model year motor vehicles. Any 
future regulation affecting the sale or distribution of motor vehicles 
or engines manufactured before the model year 1984 in high altitude 
areas of the country shall take effect no earlier than model year 1981.
    (2) Any such future regulation applicable to high altitude vehicles 
or engines shall not require a percentage of reduction in the emissions 
of such vehicles which is greater than the required percentage of 
reduction in emissions from motor vehicles as set forth in subsection 
(b) of this section. This percentage reduction shall be determined by 
comparing any proposed high altitude emission standards to high altitude 
emissions from vehicles manufactured during model year 1970. In no event 
shall regulations applicable to high altitude vehicles manufactured 
before the model year 1984 establish a numerical standard which is more 
stringent than that applicable to vehicles certified under non-high 
altitude conditions.
    (3) Section 7607(d) of this title shall apply to any high altitude 
regulation referred to in paragraph (2) and before promulgating any such 
regulation, the Administrator shall consider and make a finding with 
respect to--
        (A) the economic impact upon consumers, individual high altitude 
    dealers, and the automobile industry of any such regulation, 
    including the economic impact which was experienced as a result of 
    the regulation imposed during model year 1977 with respect to high 
    altitude certification requirements;
        (B) the present and future availability of emission control 
    technology capable of meeting the applicable vehicle and engine 
    emission requirements without reducing model availability; and
        (C) the likelihood that the adoption of such a high altitude 
    regulation will result in any significant improvement in air quality 
    in any area to which it shall apply.

(g) Light-duty trucks up to 6,000 lbs. GVWR and light-duty vehicles; 
        standards for model years after 1993

                  (1) NMHC, CO, and NO<INF>x</INF>

        Effective with respect to the model year 1994 and thereafter, 
    the regulations under subsection (a) of this section applicable to 
    emissions of nonmethane hydrocarbons (NMHC), carbon monoxide (CO), 
    and oxides of nitrogen (NO<INF>x</INF>) from light-duty trucks 
    (LDTs) of up to 6,000 lbs. gross vehicle weight rating (GVWR) and 
    light-duty vehicles (LDVs) shall contain standards which provide 
    that emissions from a percentage of each manufacturer's sales volume 
    of such vehicles and trucks shall comply with the levels specified 
    in table G. The percentage shall be as specified in the 
    implementation schedule below:

table g--emission standards for nmhc, co, and no<INF>x</INF> from light-duty tr
ucks of up to 6,000 lbs. gvwr and light-duty
                                                    vehicles
-------------------------------------------------------------------------------
---------------------------------
                                                                      Column A 
                 Column B
                                                             ------------------
---------------------------------
                        Vehicle type                              (5 yrs/50,000
 mi)        (10 yrs/100,000 mi)
                                                             ------------------
---------------------------------
                                                               NMHC     CO     
  NO<INF>x</INF>     NMHC     CO       NO<INF>x</INF>
-------------------------------------------------------------------------------
---------------------------------
LDTs (0-3,750 lbs. LVW) and light-duty vehicles.............    0.25     3.4   
  0.4*     0.31     4.2      0.6*
LDTs (3,751-5,750 lbs. LVW).................................    0.32     4.4   
  0.7**    0.40     5.5      0.97
-------------------------------------------------------------------------------
---------------------------------
Standards are expressed in grams per mile (gpm).
For standards under column A, for purposes of certification under section 7525 
of this title, the applicable
  useful life shall be 5 years or 50,000 miles (or the equivalent), whichever f
irst occurs.
For standards under column B, for purposes of certification under section 7525 
of this title, the applicable
  useful life shall be 10 years or 100,000 miles (or the equivalent), whichever
 first occurs.
*In the case of diesel-fueled LDTs (0-3,750 lvw) and light-duty vehicles, befor
e the model year 2004, in lieu of
  the 0.4 and 0.6 standards for NO<INF>x</INF>, the applicable standards for NO
<INF>x</INF> shall be 1.0 gpm for a useful life of 5
  years or 50,000 miles (or the equivalent), whichever first occurs, and 1.25 g
pm for a useful life of 10 years
  or 100,000 miles (or the equivalent) whichever first occurs.
**This standard does not apply to diesel-fueled LDTs (3,751-5,750 lbs. LVW).


              Implementation Schedule for Table G Standards
------------------------------------------------------------------------
                Model year                          Percentage*
------------------------------------------------------------------------
1994.....................................                40
1995.....................................                80
after 1995...............................               100
------------------------------------------------------------------------
*Percentages in the table refer to a percentage of each manufacturer's
  sales volume.

                           (2) PM Standard

        Effective with respect to model year 1994 and thereafter in the 
    case of light-duty vehicles, and effective with respect to the model 
    year 1995 and thereafter in the case of light-duty trucks (LDTs) of 
    up to 6,000 lbs. gross vehicle weight rating (GVWR), the regulations 
    under subsection (a) of this section applicable to emissions of 
    particulate matter (PM) from such vehicles and trucks shall contain 
    standards which provide that such emissions from a percentage of 
    each manufacturer's sales volume of such vehicles and trucks shall 
    not exceed the levels specified in the table below. The percentage 
    shall be as specified in the Implementation Schedule below.

              PM Standard for LDTs of up to 6,000 lbs. GVWR
------------------------------------------------------------------------
            Useful life period                        Standard
------------------------------------------------------------------------
5/50,000.................................  0.08 gpm
10/100,000...............................  0.10 gpm
------------------------------------------------------------------------
The applicable useful life, for purposes of certification under section
  7525 of this title and for purposes of in-use compliance under section
  7541 of this title, shall be 5 years or 50,000 miles (or the
  equivalent), whichever first occurs, in the case of the 5/50,000
  standard.
The applicable useful life, for purposes of certification under section
  7525 of this title and for purposes of in-use compliance under section
  7541 of this title, shall be 10 years or 100,000 miles (or the
  equivalent), whichever first occurs in the case of the 10/100,000
  standard.


                Implementation Schedule for PM Standards
------------------------------------------------------------------------
           Model year            Light-duty vehicles         LDTs
------------------------------------------------------------------------
1994...........................          40%*         ..................
1995...........................          80%*                 40%*
1996...........................         100%*                 80%*
after 1996.....................         100%*                100%*
------------------------------------------------------------------------
*Percentages in the table refer to a percentage of each manufacturer's
  sales volume.

(h) Light-duty trucks of more than 6,000 lbs. GVWR; standards for model 
        years after 1995

    Effective with respect to the model year 1996 and thereafter, the 
regulations under subsection (a) of this section applicable to emissions 
of nonmethane hydrocarbons (NMHC), carbon monoxide (CO), oxides of 
nitrogen (NO<INF>x</INF>), and particulate matter (PM) from light-duty 
trucks (LDTs) of more than 6,000 lbs. gross vehicle weight rating (GVWR) 
shall contain standards which provide that emissions from a specified 
percentage of each manufacturer's sales volume of such trucks shall 
comply with the levels specified in table H. The specified percentage 
shall be 50 percent in model year 1996 and 100 percent thereafter.

table h--emission standards for nmhc and co from gasoline and diesel fueled lig
ht-duty trucks of more than 6,000
                                                    lbs. gvwr
-------------------------------------------------------------------------------
---------------------------------
                                                                 Column A      
              Column B
                                                         ----------------------
---------------------------------
                     LDT Test weight                         (5 yrs/50,000 mi) 
         (11 yrs/120,000 mi)
                                                         ----------------------
---------------------------------
                                                           NMHC     CO      NO<
INF>x</INF>    NMHC     CO      NO<INF>x</INF>     PM
-------------------------------------------------------------------------------
---------------------------------
3,751-5,750 lbs. TW.....................................    0.32     4.4    0.7
*    0.46     6.4    0.98    0.10
Over 5,750 lbs. TW......................................    0.39     5.0    1.1
*    0.56     7.3    1.53    0.12
-------------------------------------------------------------------------------
---------------------------------
Standards are expressed in grams per mile (GPM).
For standards under column A, for purposes of certification under section 7525 
of this title, the applicable
  useful life shall be 5 years or 50,000 miles (or the equivalent) whichever fi
rst occurs.
For standards under column B, for purposes of certification under section 7525 
of this title, the applicable
  useful life shall be 11 years or 120,000 miles (or the equivalent), whichever
 first occurs.
*Not applicable to diesel-fueled LDTs.

(i) Phase II study for certain light-duty vehicles and light-duty trucks

    (1) The Administrator, with the participation of the Office of 
Technology Assessment, shall study whether or not further reductions in 
emissions from light-duty vehicles and light-duty trucks should be 
required pursuant to this subchapter. The study shall consider whether 
to establish with respect to model years commencing after January 1, 
2003, the standards and useful life period for gasoline and diesel-
fueled light-duty vehicles and light-duty trucks with a loaded vehicle 
weight (LVW) of 3,750 lbs. or less specified in the following table:

table 3--pending emission standards for gasoline and diesel fueled light-
       duty vehicles and light-duty trucks 3,750 lbs. lvw or less
------------------------------------------------------------------------
              Pollutant                         Emission level*
------------------------------------------------------------------------
NMHC.................................  0.125 GPM
NO<INF>x</INF>..................................  0.2 GPM
CO...................................  1.7 GPM
------------------------------------------------------------------------
*Emission levels are expressed in grams per mile (GPM). For vehicles and
  engines subject to this subsection for purposes of subsection (d) of
  this section and any reference thereto, the useful life of such
  vehicles and engines shall be a period of 10 years or 100,000 miles
  (or the equivalent), whichever first occurs.

Such study shall also consider other standards and useful life periods 
which are more stringent or less stringent than those set forth in table 
3 (but more stringent than those referred to in subsections (g) and (h) 
of this section).
    (2)(A) As part of the study under paragraph (1), the Administrator 
shall examine the need for further reductions in emissions in order to 
attain or maintain the national ambient air quality standards, taking 
into consideration the waiver provisions of section 7543(b) of this 
title. As part of such study, the Administrator shall also examine--
        (i) the availability of technology (including the costs 
    thereof), in the case of light-duty vehicles and light-duty trucks 
    with a loaded vehicle weight (LVW) of 3,750 lbs. or less, for 
    meeting more stringent emission standards than those provided in 
    subsections (g) and (h) of this section for model years commencing 
    not earlier than after January 1, 2003, and not later than model 
    year 2006, including the lead time and safety and energy impacts of 
    meeting more stringent emission standards; and
        (ii) the need for, and cost effectiveness of, obtaining further 
    reductions in emissions from such light-duty vehicles and light-duty 
    trucks, taking into consideration alternative means of attaining or 
    maintaining the national primary ambient air quality standards 
    pursuant to State implementation plans and other requirements of 
    this chapter, including their feasibility and cost effectiveness.

    (B) The Administrator shall submit a report to Congress no later 
than June 1, 1997, containing the results of the study under this 
subsection, including the results of the examination conducted under 
subparagraph (A). Before submittal of such report the Administrator 
shall provide a reasonable opportunity for public comment and shall 
include a summary of such comments in the report to Congress.
    (3)(A) Based on the study under paragraph (1) the Administrator 
shall determine, by rule, within 3 calendar years after the report is 
submitted to Congress, but not later than December 31, 1999, whether--
        (i) there is a need for further reductions in emissions as 
    provided in paragraph (2)(A);
        (ii) the technology for meeting more stringent emission 
    standards will be available, as provided in paragraph (2)(A)(i), in 
    the case of light-duty vehicles and light-duty trucks with a loaded 
    vehicle weight (LVW) of 3,750 lbs. or less, for model years 
    commencing not earlier than January 1, 2003, and not later than 
    model year 2006, considering the factors listed in paragraph 
    (2)(A)(i); and
        (iii) obtaining further reductions in emissions from such 
    vehicles will be needed and cost effective, taking into 
    consideration alternatives as provided in paragraph (2)(A)(ii).

The rulemaking under this paragraph shall commence within 3 months after 
submission of the report to Congress under paragraph (2)(B).
    (B) If the Administrator determines under subparagraph (A) that--
        (i) there is no need for further reductions in emissions as 
    provided in paragraph (2)(A);
        (ii) the technology for meeting more stringent emission 
    standards will not be available as provided in paragraph (2)(A)(i), 
    in the case of light-duty vehicles and light-duty trucks with a 
    loaded vehicle weight (LVW) of 3,750 lbs. or less, for model years 
    commencing not earlier than January 1, 2003, and not later than 
    model year 2006, considering the factors listed in paragraph 
    (2)(A)(i); or
        (iii) obtaining further reductions in emissions from such 
    vehicles will not be needed or cost effective, taking into 
    consideration alternatives as provided in paragraph (2)(A)(ii),

the Administrator shall not promulgate more stringent standards than 
those in effect pursuant to subsections (g) and (h) of this section. 
Nothing in this paragraph shall prohibit the Administrator from 
exercising the Administrator's authority under subsection (a) of this 
section to promulgate more stringent standards for light-duty vehicles 
and light-duty trucks with a loaded vehicle weight (LVW) of 3,750 lbs. 
or less at any other time thereafter in accordance with subsection (a) 
of this section.
    (C) If the Administrator determines under subparagraph (A) that--
        (i) there is a need for further reductions in emissions as 
    provided in paragraph (2)(A);
        (ii) the technology for meeting more stringent emission 
    standards will be available, as provided in paragraph (2)(A)(i), in 
    the case of light-duty vehicles and light-duty trucks with a loaded 
    vehicle weight (LVW) of 3,750 lbs. or less, for model years 
    commencing not earlier than January 1, 2003, and not later than 
    model year 2006, considering the factors listed in paragraph 
    (2)(A)(i); and
        (iii) obtaining further reductions in emissions from such 
    vehicles will be needed and cost effective, taking into 
    consideration alternatives as provided in paragraph (2)(A)(ii),

the Administrator shall either promulgate the standards (and useful life 
periods) set forth in Table 3 in paragraph (1) or promulgate alternative 
standards (and useful life periods) which are more stringent than those 
referred to in subsections (g) and (h) of this section. Any such 
standards (or useful life periods) promulgated by the Administrator 
shall take effect with respect to any such vehicles or engines no 
earlier than the model year 2003 but not later than model year 2006, as 
determined by the Administrator in the rule.
    (D) Nothing in this paragraph shall be construed by the 
Administrator or by a court as a presumption that any standards (or 
useful life period) set forth in Table 3 shall be promulgated in the 
rulemaking required under this paragraph. The action required of the 
Administrator in accordance with this paragraph shall be treated as a 
nondiscretionary duty for purposes of section 7604(a)(2) of this title 
(relating to citizen suits).
    (E) Unless the Administrator determines not to promulgate more 
stringent standards as provided in subparagraph (B) or to postpone the 
effective date of standards referred to in Table 3 in paragraph (1) or 
to establish alternative standards as provided in subparagraph (C), 
effective with respect to model years commencing after January 1, 2003, 
the regulations under subsection (a) of this section applicable to 
emissions of nonmethane hydrocarbons (NMHC), oxides of nitrogen 
(NO<INF>x</INF>), and carbon monoxide (CO) from motor vehicles and motor 
vehicle engines in the classes specified in Table 3 in paragraph (1) 
above shall contain standards which provide that emissions may not 
exceed the pending emission levels specified in Table 3 in paragraph 
(1).

(j) Cold CO standard

                             (1) Phase I

        Not later than 12 months after November 15, 1990, the 
    Administrator shall promulgate regulations under subsection (a) of 
    this section applicable to emissions of carbon monoxide from 1994 
    and later model year light-duty vehicles and light-duty trucks when 
    operated at 20 degrees Fahrenheit. The regulations shall contain 
    standards which provide that emissions of carbon monoxide from a 
    manufacturer's vehicles when operated at 20 degrees Fahrenheit may 
    not exceed, in the case of light-duty vehicles, 10.0 grams per mile, 
    and in the case of light-duty trucks, a level comparable in 
    stringency to the standard applicable to light-duty vehicles. The 
    standards shall take effect after model year 1993 according to a 
    phase-in schedule which requires a percentage of each manufacturer's 
    sales volume of light-duty vehicles and light-duty trucks to comply 
    with applicable standards after model year 1993. The percentage 
    shall be as specified in the following table:

               Phase-In Schedule for Cold Start Standards
------------------------------------------------------------------------
                Model Year                           Percentage
------------------------------------------------------------------------
1994.....................................                40
1995.....................................                80
1996 and after...........................               100
------------------------------------------------------------------------

                            (2) Phase II

        (A) Not later than June 1, 1997, the Administrator shall 
    complete a study assessing the need for further reductions in 
    emissions of carbon monoxide and the maximum reductions in such 
    emissions achievable from model year 2001 and later model year 
    light-duty vehicles and light-duty trucks when operated at 20 
    degrees Fahrenheit.
        (B)(i) If as of June 1, 1997, 6 or more nonattainment areas have 
    a carbon monoxide design value of 9.5 ppm or greater, the 
    regulations under subsection (a)(1) of this section applicable to 
    emissions of carbon monoxide from model year 2002 and later model 
    year light-duty vehicles and light-duty trucks shall contain 
    standards which provide that emissions of carbon monoxide from such 
    vehicles and trucks when operated at 20 degrees Fahrenheit may not 
    exceed 3.4 grams per mile (gpm) in the case of light-duty vehicles 
    and 4.4 grams per mile (gpm) in the case of light-duty trucks up to 
    6,000 GVWR and a level comparable in stringency in the case of 
    light-duty trucks 6,000 GVWR and above.
        (ii) In determining for purposes of this subparagraph whether 6 
    or more nonattainment areas have a carbon monoxide design value of 
    9.5 ppm or greater, the Administrator shall exclude the areas of 
    Steubenville, Ohio, and Oshkosh, Wisconsin.

         (3) Useful-life for phase I and phase II standards

        In the case of the standards referred to in paragraphs (1) and 
    (2), for purposes of certification under section 7525 of this title 
    and in-use compliance under section 7541 of this title, the 
    applicable useful life period shall be 5 years or 50,000 miles, 
    whichever first occurs, except that the Administrator may extend 
    such useful life period (for purposes of section 7525 of this title, 
    or section 7541 of this title, or both) if he determines that it is 
    feasible for vehicles and engines subject to such standards to meet 
    such standards for a longer useful life. If the Administrator 
    extends such useful life period, the Administrator may make an 
    appropriate adjustment of applicable standards for such extended 
    useful life. No such extended useful life shall extend beyond the 
    useful life period provided in regulations under subsection (d) of 
    this section.

                 (4) Heavy-duty vehicles and engines

        The Administrator may also promulgate regulations under 
    subsection (a)(1) of this section applicable to emissions of carbon 
    monoxide from heavy-duty vehicles and engines when operated at cold 
    temperatures.

(k) Control of evaporative emissions

    The Administrator shall promulgate (and from time to time revise) 
regulations applicable to evaporative emissions of hydrocarbons from all 
gasoline-fueled motor vehicles--
        (1) during operation; and
        (2) over 2 or more days of nonuse;

under ozone-prone summertime conditions (as determined by regulations of 
the Administrator). The regulations shall take effect as expeditiously 
as possible and shall require the greatest degree of emission reduction 
achievable by means reasonably expected to be available for production 
during any model year to which the regulations apply, giving appropriate 
consideration to fuel volatility, and to cost, energy, and safety 
factors associated with the application of the appropriate technology. 
The Administrator shall commence a rulemaking under this subsection 
within 12 months after November 15, 1990. If final regulations are not 
promulgated under this subsection within 18 months after November 15, 
1990, the Administrator shall submit a statement to the Congress 
containing an explanation of the reasons for the delay and a date 
certain for promulgation of such final regulations in accordance with 
this chapter. Such date certain shall not be later than 15 months after 
the expiration of such 18 month deadline.

(l) Mobile source-related air toxics

                              (1) Study

        Not later than 18 months after November 15, 1990, the 
    Administrator shall complete a study of the need for, and 
    feasibility of, controlling emissions of toxic air pollutants which 
    are unregulated under this chapter and associated with motor 
    vehicles and motor vehicle fuels, and the need for, and feasibility 
    of, controlling such emissions and the means and measures for such 
    controls. The study shall focus on those categories of emissions 
    that pose the greatest risk to human health or about which 
    significant uncertainties remain, including emissions of benzene, 
    formaldehyde, and 1,3 butadiene. The proposed report shall be 
    available for public review and comment and shall include a summary 
    of all comments.

                            (2) Standards

        Within 54 months after November 15, 1990, the Administrator 
    shall, based on the study under paragraph (1), promulgate (and from 
    time to time revise) regulations under subsection (a)(1) of this 
    section or section 7545(c)(1) of this title containing reasonable 
    requirements to control hazardous air pollutants from motor vehicles 
    and motor vehicle fuels. The regulations shall contain standards for 
    such fuels or vehicles, or both, which the Administrator determines 
    reflect the greatest degree of emission reduction achievable through 
    the application of technology which will be available, taking into 
    consideration the standards established under subsection (a) of this 
    section, the availability and costs of the technology, and noise, 
    energy, and safety factors, and lead time. Such regulations shall 
    not be inconsistent with standards under subsection (a) of this 
    section. The regulations shall, at a minimum, apply to emissions of 
    benzene and formaldehyde.

(m) Emissions control diagnostics

                           (1) Regulations

        Within 18 months after November 15, 1990, the Administrator 
    shall promulgate regulations under subsection (a) of this section 
    requiring manufacturers to install on all new light duty vehicles 
    and light duty trucks diagnostics systems capable of--
            (A) accurately identifying for the vehicle's useful life as 
        established under this section, emission-related systems 
        deterioration or malfunction, including, at a minimum, the 
        catalytic converter and oxygen sensor, which could cause or 
        result in failure of the vehicles to comply with emission 
        standards established under this section,
            (B) alerting the vehicle's owner or operator to the likely 
        need for emission-related components or systems maintenance or 
        repair,
            (C) storing and retrieving fault codes specified by the 
        Administrator, and
            (D) providing access to stored information in a manner 
        specified by the Administrator.

    The Administrator may, in the Administrator's discretion, promulgate 
    regulations requiring manufacturers to install such onboard 
    diagnostic systems on heavy-duty vehicles and engines.

                         (2) Effective date

        The regulations required under paragraph (1) of this subsection 
    shall take effect in model year 1994, except that the Administrator 
    may waive the application of such regulations for model year 1994 or 
    1995 (or both) with respect to any class or category of motor 
    vehicles if the Administrator determines that it would be infeasible 
    to apply the regulations to that class or category in such model 
    year or years, consistent with corresponding regulations or policies 
    adopted by the California Air Resources Board for such systems.

                        (3) State inspection

        The Administrator shall by regulation require States that have 
    implementation plans containing motor vehicle inspection and 
    maintenance programs to amend their plans within 2 years after 
    promulgation of such regulations to provide for inspection of 
    onboard diagnostics systems (as prescribed by regulations under 
    paragraph (1) of this subsection) and for the maintenance or repair 
    of malfunctions or system deterioration identified by or affecting 
    such diagnostics systems. Such regulations shall not be inconsistent 
    with the provisions for warranties promulgated under section 7541(a) 
    and (b) of this title.

                      (4) Specific requirements

        In promulgating regulations under this subsection, the 
    Administrator shall require--
            (A) that any connectors through which the emission control 
        diagnostics system is accessed for inspection, diagnosis, 
        service, or repair shall be standard and uniform on all motor 
        vehicles and motor vehicle engines;
            (B) that access to the emission control diagnostics system 
        through such connectors shall be unrestricted and shall not 
        require any access code or any device which is only available 
        from a vehicle manufacturer; and
            (C) that the output of the data from the emission control 
        diagnostics system through such connectors shall be usable 
        without the need for any unique decoding information or device.

                    (5) Information availability

        The Administrator, by regulation, shall require (subject to the 
    provisions of section 7542(c) of this title regarding the protection 
    of methods or processes entitled to protection as trade secrets) 
    manufacturers to provide promptly to any person engaged in the 
    repairing or servicing of motor vehicles or motor vehicle engines, 
    and the Administrator for use by any such persons, with any and all 
    information needed to make use of the emission control diagnostics 
    system prescribed under this subsection and such other information 
    including instructions for making emission related diagnosis and 
    repairs. No such information may be withheld under section 7542(c) 
    of this title if that information is provided (directly or 
    indirectly) by the manufacturer to franchised dealers or other 
    persons engaged in the repair, diagnosing, or servicing of motor 
    vehicles or motor vehicle engines. Such information shall also be 
    available to the Administrator, subject to section 7542(c) of this 
    title, in carrying out the Administrator's responsibilities under 
    this section.

(f) \5\ Model years after 1990
---------------------------------------------------------------------------

    \5\ So in original. Probably should be ``(n)''.
---------------------------------------------------------------------------
    For model years prior to model year 1994, the regulations under 
subsection (a) of this section applicable to buses other than those 
subject to standards under section 7554 of this title shall contain a 
standard which provides that emissions of particulate matter (PM) from 
such buses may not exceed the standards set forth in the following 
table:

                          pm standard for buses
------------------------------------------------------------------------
                Model year                           Standard*
------------------------------------------------------------------------
1991.....................................               0.25
1992.....................................               0.25
1993 and thereafter......................               0.10
------------------------------------------------------------------------
*Standards are expressed in grams per brake horsepower hour (g/bhp/hr).

(July 14, 1955, ch. 360, title II, Sec. 202, as added Pub. L. 89-272, 
title I, Sec. 101(8), Oct. 20, 1965, 79 Stat. 992; amended Pub. L. 90-
148, Sec. 2, Nov. 21, 1967, 81 Stat. 499; Pub. L. 91-604, Sec. 6(a), 
Dec. 31, 1970, 84 Stat. 1690; Pub. L. 93-319, Sec. 5, June 22, 1974, 88 
Stat. 258; Pub. L. 95-95, title II, Secs. 201, 202(b), 213(b), 214(a), 
215-217, 224(a), (b), (g), title IV, Sec. 401(d), Aug. 7, 1977, 91 Stat. 
751-753, 758-761, 765, 767, 769, 791; Pub. L. 95-190, Sec. 14(a)(60)-
(65), (b)(5), Nov. 16, 1977, 91 Stat. 1403, 1405; Pub. L. 101-549, title 
II, Secs. 201-207, 227(b), 230(1)-(5), Nov. 15, 1990, 104 Stat. 2472-
2481, 2507, 2529.)

                       References in Text

    The enactment of the Clean Air Act Amendments of 1990, referred to 
in subsec. (a)(3)(B), probably means the enactment of Pub. L. 101-549, 
Nov. 15, 1990, 104 Stat. 2399, which was approved Nov. 15, 1990. For 
complete classification of this Act to the Code, see Short Title note 
set out under section 7401 of this title and Tables.
    Section 7525(f)(1) of this title, referred to in subsec. (a)(3)(E), 
was redesignated section 7525(f) of this title by Pub. L. 101-549, title 
II, Sec. 230(8), Nov. 15, 1990, 104 Stat. 2529.
    The Energy Policy and Conservation Act, referred to in subsec. 
(b)(3)(C), is Pub. L. 94-163, Dec. 22, 1975, 89 Stat. 871, as amended, 
which is classified principally to chapter 77 (Sec. 6201 et seq.) of 
this title. For complete classification of this Act to the Code, see 
Short Title note set out under section 6201 of this title and Tables.

                          Codification

    Section was formerly classified to section 1857f-1 of this title.


                               Amendments

    1990--Subsec. (a)(3)(A). Pub. L. 101-549, Sec. 201(1), added subpar. 
(A) and struck out former subpar. (A) which related to promulgation of 
regulations applicable to reduction of emissions from heavy-duty 
vehicles or engines manufactured during and after model year 1979 in the 
case of carbon monoxide, hydrocarbons, and oxides of nitrogen, and from 
vehicles manufactured during and after model year 1981 in the case of 
particulate matter.
    Subsec. (a)(3)(B). Pub. L. 101-549, Sec. 201(1), added subpar. (B) 
and struck out former subpar. (B) which read as follows: ``During the 
period of June 1 through December 31, 1978, in the case of hydrocarbons 
and carbon monoxide, or during the period of June 1 through December 31, 
1980, in the case of oxides of nitrogen, and during each period of June 
1 through December 31 of each third year thereafter, the Administrator 
may, after notice and opportunity for a public hearing promulgate 
regulations revising any standard prescribed as provided in subparagraph 
(A)(ii) for any class or category of heavy-duty vehicles or engines. 
Such standard shall apply only for the period of three model years 
beginning four model years after the model year in which such revised 
standard is promulgated. In revising any standard under this 
subparagraph for any such three model year period, the Administrator 
shall determine the maximum degree of emission reduction which can be 
achieved by means reasonably expected to be available for production of 
such period and shall prescribe a revised emission standard in 
accordance with such determination. Such revised standard shall require 
a reduction of emissions from any standard which applies in the previous 
model year.''
    Subsec. (a)(3)(C). Pub. L. 101-549, Sec. 201(1), added subpar. (C) 
and struck out former subpar. (C) which read as follows: ``Action 
revising any standard for any period may be taken by the Administrator 
under subparagraph (B) only if he finds--
        ``(i) that compliance with the emission standards otherwise 
    applicable for such model year cannot be achieved by technology, 
    processes, operating methods, or other alternatives reasonably 
    expected to be available for production for such model year without 
    increasing cost or decreasing fuel economy to an excessive and 
    unreasonable degree; and
        ``(ii) the National Academy of Sciences has not, pursuant to its 
    study and investigation under subsection (c) of this section, issued 
    a report substantially contrary to the findings of the Administrator 
    under clause (i).''
    Subsec. (a)(3)(D). Pub. L. 101-549, Sec. 201(1), added subpar. (D) 
and struck out former subpar. (D) which read as follows: ``A report 
shall be made to the Congress with respect to any standard revised under 
subparagraph (B) which shall contain--
        ``(i) a summary of the health effects found, or believed to be 
    associated with, the pollutant covered by such standard,
        ``(ii) an analysis of the cost-effectiveness of other strategies 
    for attaining and maintaining national ambient air quality standards 
    and carrying out regulations under part C of subchapter I (relating 
    to significant deterioration) in relation to the cost-effectiveness 
    for such purposes of standards which, but for such revision, would 
    apply.
        ``(iii) a summary of the research and development efforts and 
    progress being made by each manufacturer for purposes of meeting the 
    standards promulgated as provided in subparagraph (A)(ii) or, if 
    applicable, subparagraph (E), and
        ``(iv) specific findings as to the relative costs of compliance, 
    and relative fuel economy, which may be expected to result from the 
    application for any model year of such revised standard and the 
    application for such model year of the standard, which, but for such 
    revision, would apply.''
    Subsec. (a)(3)(E), (F). Pub. L. 101-549, Sec. 201, redesignated 
subpar. (F) as (E), inserted heading, and struck out former subpar. (E) 
which read as follows:
    ``(i) The Administrator shall conduct a continuing pollutant-
specific study concerning the effects of each air pollutant emitted from 
heavy-duty vehicles or engines and from other sources of mobile source 
related pollutants on the public health and welfare. The results of such 
study shall be published in the Federal Register and reported to the 
Congress not later than June 1, 1978, in the case of hydrocarbons and 
carbon monoxide, and June 1, 1980, in the case of oxides of nitrogen, 
and before June 1 of each third year thereafter.
    ``(ii) On the basis of such study and such other information as is 
available to him (including the studies under section 7548 of this 
title), the Administrator may, after notice and opportunity for a public 
hearing, promulgate regulations under paragraph (1) of this subsection 
changing any standard prescribed in subparagraph (A)(ii) (or revised 
under subparagraph (B) or previously changed under this subparagraph). 
No such changed standard shall apply for any model year before the model 
year four years after the model year during which regulations containing 
such changed standard are promulgated.''
    Subsec. (a)(4)(A), (B). Pub. L. 101-549, Sec. 227(b), substituted 
``requirements prescribed under this subchapter'' for ``standards 
prescribed under this subsection''.
    Subsec. (a)(6). Pub. L. 101-549, Sec. 202, amended par. (6) 
generally. Prior to amendment, par. (6) read as follows: ``The 
Administrator shall determine the feasibility and desirability of 
requiring new motor vehicles to utilize onboard hydrocarbon control 
technology which would avoid the necessity of gasoline vapor recovery of 
uncontrolled emissions emanating from the fueling of motor vehicles. The 
Administrator shall compare the costs and effectiveness of such 
technology to that of implementing and maintaining vapor recovery 
systems (taking into consideration such factors as fuel economy, 
economic costs of such technology, administrative burdens, and equitable 
distribution of costs). If the Administrator finds that it is feasible 
and desirable to employ such technology, he shall, after consultation 
with the Secretary of Transportation with respect to motor vehicle 
safety, prescribe, by regulation, standards requiring the use of onboard 
hydrocarbon technology which shall not become effective until the 
introduction to the model year for which it would be feasible to 
implement such standards, taking into consideration compliance costs and 
the restraints of an adequate lead time for design and production.''
    Subsec. (b)(1)(C). Pub. L. 101-549, Sec. 203(c), amended subpar. (C) 
generally. Prior to amendment, subpar. (C) read as follows: ``Effective 
with respect to vehicles and engines manufactured after model year 1978 
(or in the case of heavy-duty vehicles or engines, such later model year 
as the Administrator determines is the earliest feasible model year), 
the test procedure promulgated under paragraph (2) for measurement of 
evaporative emissions of hydrocarbons shall require that such emissions 
be measured from the vehicle or engine as a whole. Regulations to carry 
out this subparagraph shall be promulgated not later than two hundred 
and seventy days after August 7, 1977.''
    Subsec. (b)(2). Pub. L. 101-549, Sec. 203(d), amended par. (2) 
generally. Prior to amendment, par. (2) read as follows: ``Emission 
standards under paragraph (1), and measurement techniques on which such 
standards are based (if not promulgated prior to December 31, 1970), 
shall be prescribed by regulation within 180 days after such date.''
    Subsec. (b)(3). Pub. L. 101-549, Sec. 230(4), redesignated par. (6) 
relating to waiver of standards for oxides of nitrogen as par. (3), 
struck out subpar. (A) designation before ``Upon the petition'', 
redesignated former cls. (i) to (iii) as subpars. (A) to (C), 
respectively, and struck out former subpar. (B) which authorized the 
Administrator to waive the standard under subsec. (b)(1)(B) of this 
section for emissions of oxides of nitrogen from light-duty vehicles and 
engines beginning in model year 1981 after providing notice and 
opportunity for a public hearing, and set forth conditions under which a 
waiver could be granted.
    Subsec. (b)(3)(B). Pub. L. 101-549, Sec. 230(1), in the par. (3) 
defining terms for purposes of this part struck out subpar. (B) which 
defined ``light duty vehicles and engines''.
    Subsec. (b)(4). Pub. L. 101-549, Sec. 230(2), struck out par. (4) 
which read as follows: ``On July 1 of 1971, and of each year thereafter, 
the Administrator shall report to the Congress with respect to the 
development of systems necessary to implement the emission standards 
established pursuant to this section. Such reports shall include 
information regarding the continuing effects of such air pollutants 
subject to standards under this section on the public health and 
welfare, the extent and progress of efforts being made to develop the 
necessary systems, the costs associated with development and application 
of such systems, and following such hearings as he may deem advisable, 
any recommendations for additional congressional action necessary to 
achieve the purposes of this chapter. In gathering information for the 
purposes of this paragraph and in connection with any hearing, the 
provisions of section 7607(a) of this title (relating to subpenas) shall 
apply.''
    Subsec. (b)(5). Pub. L. 101-549, Sec. 230(3), struck out par. (5) 
which related to waivers for model years 1981 and 1982 of the effective 
date of the emissions standard required under par. (1)(A) for carbon 
monoxide applicable to light-duty vehicles and engines manufactured in 
those model years.
    Subsec. (b)(6). Pub. L. 101-549, Sec. 230(4), redesignated par. (6) 
as (3).
    Subsec. (b)(7). Pub. L. 101-549, Sec. 230(5), struck out par. (7) 
which read as follows: ``The Congress hereby declares and establishes as 
a research objective, the development of propulsion systems and emission 
control technology to achieve standards which represent a reduction of 
at least 90 per centum from the average emissions of oxides of nitrogen 
actually measured from light duty motor vehicles manufactured in model 
year 1971 not subject to any Federal or State emission standard for 
oxides of nitrogen. The Administrator shall, by regulations promulgated 
within one hundred and eighty days after August 7, 1977, require each 
manufacturer whose sales represent at least 0.5 per centum of light duty 
motor vehicle sales in the United States, to build and, on a regular 
basis, demonstrate the operation of light duty motor vehicles that meet 
this research objective, in addition to any other applicable standards 
or requirements for other pollutants under this chapter. Such 
demonstration vehicles shall be submitted to the Administrator no later 
than model year 1979 and in each model year thereafter. Such 
demonstration shall, in accordance with applicable regulations, to the 
greatest extent possible, (A) be designed to encourage the development 
of new powerplant and emission control technologies that are fuel 
efficient, (B) assure that the demonstration vehicles are or could 
reasonably be expected to be within the productive capability of the 
manufacturers, and (C) assure the utilization of optimum engine, fuel, 
and emission control systems.''
    Subsec. (d). Pub. L. 101-549, Sec. 203(b)(1), substituted ``provide 
that except where a different useful life period is specified in this 
subchapter'' for ``provide that''.
    Subsec. (d)(1). Pub. L. 101-549, Sec. 203(b)(2), (3), inserted ``and 
light-duty trucks up to 3,750 lbs. LVW and up to 6,000 lbs. GVWR'' after 
``engines'' and substituted for semicolon at end ``, except that in the 
case of any requirement of this section which first becomes applicable 
after November 15, 1990, where the useful life period is not otherwise 
specified for such vehicles and engines, the period shall be 10 years or 
100,000 miles (or the equivalent), whichever first occurs, with testing 
for purposes of in-use compliance under section 7541 of this title up to 
(but not beyond) 7 years or 75,000 miles (or the equivalent), whichever 
first occurs;''.
    Subsec. (f). Pub. L. 101-549, Sec. 207(b), added (after subsec. (m) 
at end) subsec. (f) relating to regulations applicable to buses for 
model years after 1990.
    Subsecs. (g) to (i). Pub. L. 101-549, Sec. 203(a), added subsecs. 
(g) to (i).
    Subsecs. (j) to (m). Pub. L. 101-549, Secs. 204-207(a), added 
subsecs. (j) to (m).
    1977--Subsec. (a)(1). Pub. L. 95-190, Sec. 14(a)(60), restructured 
subsec. (a) by providing for designation of par. (1) to precede ``The 
Administrator'' in place of ``Except as''.
    Pub. L. 95-95, Sec. 401(d)(1), substituted ``Except as otherwise 
provided in subsection (b) of this section the Administrator'' for ``The 
Administrator'', ``cause, or contribute to, air pollution which may 
reasonably be anticipated to endanger public health or welfare'' for 
``causes or contributes to, or is likely to cause or contribute to, air 
pollution which endangers the public health or welfare'', and ``useful 
life (as determined under subsection (d) of this section, relating to 
useful life of vehicles for purposes of certification), whether such 
vehicles and engines are designed as complete systems or incorporate 
devices'' for ``useful life (as determined under subsection (d) of this 
section) whether such vehicles and engines are designed as complete 
systems or incorporated devices''.
    Subsec. (a)(2). Pub. L. 95-95, Sec. 214(a), substituted ``prescribed 
under paragraph (1) of this subsection'' for ``prescribed under this 
subsection''.
    Subsec. (a)(3). Pub. L. 95-95, Sec. 224(a), added par. (3).
    Subsec. (a)(3)(B). Pub. L. 95-190, Sec. 14(a)(61), (62), substituted 
provisions setting forth applicable periods of from June 1 through Dec. 
31, 1978, June 1 through Dec. 31, 1980, and during each period of June 1 
through Dec. 31 of each third year thereafter, for provisions setting 
forth applicable periods of from June 1 through Dec. 31, 1979, and 
during each period of June 1 through Dec. 31 of each third year after 
1979, and substituted ``from any'' for ``of from any''.
    Subsec. (a)(3)(E). Pub. L. 95-190, Sec. 14(a)(63), substituted 
``1978, in the case of hydrocarbons and carbon monoxide, and June 1, 
1980, in the case of oxides of nitrogen'' for ``1979,''.
    Subsec. (a)(4). Pub. L. 95-95, Sec. 214(a), added par. (4).
    Subsec. (a)(5). Pub. L. 95-95, Sec. 215, added par. (5).
    Subsec. (a)(6). Pub. L. 95-95, Sec. 216, added par. (6).
    Subsec. (b)(1)(A). Pub. L. 95-95, Sec. 201(a), substituted 
provisions setting the standards for emissions from light-duty vehicles 
and engines manufactured during the model years 1977 through 1980 for 
provisions which had set the standards for emissions from light-duty 
vehicles and engines manufactured during the model years 1975 and 1976, 
substituted ``model year 1980'' for ``model year 1977'' in provisions 
requiring a reduction of at least 90 per centum from the emissions 
allowable under standards for model year 1970, and inserted provisions 
that, unless waived as provided in par. (5), the standards for vehicles 
and engines manufactured during or after the model year 1981 represent a 
reduction of at least 90 per centum from the emissions allowable under 
standards for model year 1970.
    Subsec. (b)(1)(B). Pub. L. 95-190, Sec. 14(a)(64), (65), substituted 
``calendar year 1976'' for ``model year 1976'' and in cl. (i) 
substituted ``other'' for ``United States''.
    Pub. L. 95-95, Sec. 201(b), substituted provisions setting the 
standards for emissions from light-duty vehicles and engines 
manufactured during the model years 1977 through 1980 for provisions 
which had set the standards for emissions from light-duty vehicles and 
engines manufactured during the model years 1975 through 1977, 
substituted provisions that the standards for model years 1981 and after 
allow emissions of no more than 1.0 gram per vehicle mile for provisions 
that the standards for model year 1978 and after require a reduction of 
at least 90 per centum from the average of emissions actually measured 
from light-duty vehicles manufactured during model year 1971 which were 
not subject to any Federal or State emission standards for oxides of 
nitrogen, and inserted provisions directing the Administrator to 
prescribe separate standards for model years 1981 and 1982 for 
manufacturers whose production, by corporate identity, for model year 
1976 was less than three hundred thousand light-duty motor vehicles 
worldwide if the manufacturer's capability to meet emission standards 
depends upon United States technology and if the manufacturer cannot 
develop one.
    Subsec. (b)(1)(C). Pub. L. 95-95, Sec. 217, added subpar. (C).
    Subsec. (b)(3)(C). Pub. L. 95-95, Sec. 224(b), added subpar. (C).
    Subsec. (b)(5). Pub. L. 95-95, Sec. 201(c), substituted provisions 
setting up a procedure under which a manufacturer may apply for a waiver 
for model years 1981 and 1982 of the effective date of the emission 
standards for carbon monoxide required by par. (1)(A) for provisions 
which had set up a procedure under which a manufacturer, after Jan. 1, 
1975, could apply for a one-year suspension of the effective date of any 
emission standard required by par. (1)(A) for model year 1977.
    Subsec. (b)(6). Pub. L. 95-95, Sec. 201(c), added par. (6).
    Subsec. (b)(7). Pub. L. 95-95, Sec. 202(b), added par. (7).
    Subsec. (d)(2). Pub. L. 95-95, Sec. 224(g), as amended by Pub. L. 
95-190, Sec. 14(b)(5), to correct typographical error in directory 
language, inserted ``(other than motorcycles or motorcycle engines)'' 
after ``motor vehicle or motor vehicle engine''.
    Subsec. (d)(3). Pub. L. 95-95, Sec. 224(g), added par. (3).
    Subsec. (e). Pub. L. 95-95, Sec. 401(d)(2), substituted ``which in 
his judgment cause, or contribute to, air pollution which may reasonably 
be anticipated to endanger'' for ``which cause or contribute to, or are 
likely to cause or contribute to, air pollution which endangers''.
    Subsec. (f). Pub. L. 95-95, Sec. 213(b), added subsec. (f).
    1974--Subsec. (b)(1)(A). Pub. L. 93-319, Sec. 5(a), substituted 
``model year 1977'' for ``model year 1975'' in provisions requiring a 
reduction of at least 90 per centum from the emissions allowable under 
standards for model year 1970 and inserted provisions covering 
regulations for model years 1975 and 1976.
    Subsec. (b)(1)(B). Pub. L. 93-319, Sec. 5(b), substituted ``model 
year 1978'' for ``model year 1976'' in provisions requiring a reduction 
of at least 90 per centum from the average of emissions actually 
measured from vehicles manufactured during model year 1971 and inserted 
provisions covering regulations for model years 1975, 1976, and 1977.
    Subsec. (b)(5). Pub. L. 93-319, Sec. 5(c), (d), substituted in 
subpar. (A), ``At any time after January 1, 1975'' for ``At any time 
after January 1, 1972'', ``with respect to such manufacturer for light-
duty vehicles and engines manufactured in model year 1977'' for ``with 
respect to such manufacturer'', ``sixty days'' for ``60 days'', 
``paragraph (1)(A) of this subsection'' for ``paragraph (1)(A)'', and 
``vehicles and engines manufactured during model year 1977'' for 
``vehicles and engines manufactured during model year 1975'', 
redesignated subpars. (C) to (E) as (B) to (D), respectively, and struck 
out former subpar. (B) which had allowed manufacturers, at any time 
after Jan. 1, 1973, to file with the Administrator an application 
requesting a 1-year suspension of the effective date of any emission 
standard required by subsec. (b)(1)(B) with respect to such 
manufacturer.
    1970--Subsec. (a). Pub. L. 91-604 redesignated existing provisions 
as par. (1), substituted Administrator for Secretary as the issuing 
authority for standards, inserted references to the useful life of 
engines, and substituted the emission of any air pollutant for the 
emission of any kind of substance as the subject to be regulated, and 
added par. (2).
    Subsec. (b). Pub. L. 91-604 added subsec. (b). Former subsec. (b) 
redesignated as par. (2) of subsec. (a).
    Subsecs. (c) to (e). Pub. L. 91-604 added subsecs. (c) to (e).
    1967--Pub. L. 90-148 reenacted section without change.


                    Effective Date of 1977 Amendment

    Amendment by Pub. L. 95-95 effective Aug. 7, 1977, except as 
otherwise expressly provided, see section 406(d) of Pub. L. 95-95, set 
out as a note under section 7401 of this title.


       Modification or Rescission of Rules, Regulations, Orders, 
Determinations, Contracts, Certifications, Authorizations, Delegations, 
                            and Other Actions

    All rules, regulations, orders, determinations, contracts, 
certifications, authorizations, delegations, or other actions duly 
issued, made, or taken by or pursuant to act July 14, 1955, the Clean 
Air Act, as in effect immediately prior to the date of enactment of Pub. 
L. 95-95 [Aug. 7, 1977] to continue in full force and effect until 
modified or rescinded in accordance with act July 14, 1955, as amended 
by Pub. L. 95-95 [this chapter], see section 406(b) of Pub. L. 95-95, 
set out as an Effective Date of 1977 Amendment note under section 7401 
of this title.


          Study on Oxides of Nitrogen From Light-Duty Vehicles

    Section 202(a) of Pub. L. 95-95 provided that the Administrator of 
the Environmental Protection Agency conduct a study of the public health 
implications of attaining an emission standard on oxides of nitrogen 
from light-duty vehicles of 0.4 gram per vehicle mile, the cost and 
technological capability of attaining such standard, and the need for 
such a standard to protect public health or welfare and that the 
Administrator submit a report of such study to the Congress, together 
with recommendations not later than July 1, 1980.


     Study of Carbon Monoxide Intrusion Into Sustained-Use Vehicles

    Section 226 of Pub. L. 95-95 provided that the Administrator, in 
conjunction with the Secretary of Transportation, study the problem of 
carbon monoxide intrusion into the passenger area of sustained-use motor 
vehicles and that within one year the Administrator report to the 
Congress respecting the results of such study.


Continuing Comprehensive Studies and Investigations by National Academy 
                               of Sciences

    Section 403(f) of Pub. L. 95-95 provided that: ``The Administrator 
of the Environmental Protection Agency shall undertake to enter into 
appropriate arrangements with the National Academy of Sciences to 
conduct continuing comprehensive studies and investigations of the 
effects on public health and welfare of emissions subject to section 
202(a) of the Clean Air Act [subsec. (a) of this section] (including 
sulfur compounds) and the technological feasibility of meeting emission 
standards required to be prescribed by the Administrator by section 
202(b) of such Act [subsec. (b) of this section]. The Administrator 
shall report to the Congress within six months of the date of enactment 
of this section [Aug. 7, 1977] and each year thereafter regarding the 
status of the contractual arrangements and conditions necessary to 
implement this paragraph.''


 Study on Emission of Sulfur-Bearing Compounds From Motor Vehicles and 
                   Motor Vehicle and Aircraft Engines

    Section 403(g) of Pub. L. 95-95 provided that the Administrator of 
the Environmental Protection Agency conduct a study and report to the 
Congress by the date one year after Aug. 7, 1977, on the emission of 
sulfur-bearing compounds from motor vehicles and motor vehicle engines 
and aircraft engines.

                  Section Referred to in Other Sections

    This section is referred to in sections 7417, 7511a, 7522, 7525, 
7541, 7543, 7545, 7547, 7548, 7549, 7550, 7554, 7585, 7607, 7608, 7617 
of this title; title 49 section 30113.
