[Federal Register Volume 63, Number 61 (Tuesday, March 31, 1998)]
[Rules and Regulations]
[Pages 15294-15303]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-8214]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[CO-001-0022 and CO-001-0023; FRL-5981-4]


Approval and Promulgation of Air Quality Implementation Plan; 
Colorado; PM10 and NOX Mobile Source Emission Budget Plans 
for Denver, CO

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is approving the State Implementation Plan (SIP) revisions 
submitted by the Governor of Colorado on July 18, 1995 and April 22, 
1996. The PM10 and NOX emissions budgets contained in these 
SIP revisions are used to assess the conformity of transportation 
plans, transportation improvement programs and, where appropriate, 
federally funded projects for the applicable periods required by EPA's 
conformity rules. EPA originally proposed approval of the two emissions

[[Page 15295]]

budget SIPs on October 3, 1996. Based upon comments received on that 
proposal, EPA published a second proposal on August 5, 1997, seeking 
additional input on certain issues. In reaching its final decision to 
approve the July 18, 1995 and April 22, 1996 PM10 and NOX 
SIP submittals, EPA has considered the comments it received on both its 
October 3, 1996 and August 5, 1997 Federal Register documents.

EFFECTIVE DATE: This action is effective on April 30, 1998.

ADDRESSES: Copies of the State's original submittals, copies of 
comments received on both the October 3, 1996 and August 5, 1997 
proposals and other information are available for inspection during 
normal business hours at the Air Program, Environmental Protection 
Agency, Region VIII, 999 18th Street, Suite 500, Denver, Colorado 
80202-2466. Copies of the State documents relevant to this action are 
available for public inspection at the Colorado Department of Public 
Health and Environment, Air Pollution Control Division, 4300 Cherry 
Creek Drive South, Denver, Colorado 80222.

FOR FURTHER INFORMATION CONTACT: Callie Videtich, EPA Region 
VIII,(303)312-6434.

SUPPLEMENTARY INFORMATION:

I. Background

    On March 30, 1995, the Governor of Colorado submitted a SIP 
revision for Denver for PM10 that included attainment and maintenance 
demonstrations. In making that submittal, the Governor requested that 
EPA not act on the motor vehicle emissions budgets (also referred to as 
mobile source emissions budgets) for PM10 and NOX contained 
in Chapter XI of the PM10 SIP element. Motor vehicle emissions budgets 
are used under EPA regulations for making transportation related 
conformity determinations as required by section 176(c) of the Clean 
Air Act (CAA or Act). EPA's transportation conformity rule provides 
that these budgets establish a cap on motor vehicle-related emissions 
which cannot be exceeded by the predicted transportation system 
emissions in the future unless the cap is amended by the State and 
approved by EPA as a SIP revision and attainment and maintenance of the 
standard can be demonstrated.
    On July 18, 1995 and April 22, 1996, the Governor submitted SIP 
revisions for Denver that included additional motor vehicle emissions 
budgets for PM10 and NOX. EPA proposed approval of both of 
these emissions budgets on October 3, 1996 (61 FR 51631) along with the 
Denver PM10 SIP. Following a 60-day public comment period, EPA 
finalized approval of the Denver PM10 SIP on April 17, 1997 (62 FR 
18716). At that time, EPA did not take final action on the emissions 
budget submittals in order to more thoroughly consider comments 
received on the proposals during the public comment period. EPA 
subsequently decided to seek additional public comment regarding the 
budget submittals and, on August 5, 1997, published a second notice of 
proposed rulemaking to take comment on certain issues raised by 
commentors on the October 3, 1996 notice of proposed rulemaking. 
Specifically, EPA sought additional comment on the following issues: 
Whether Colorado met the notice and public hearing requirements of the 
Clean Air Act in adopting the PM10 emissions budget; whether Colorado 
adequately considered growth in non-mobile sources in setting the 
emissions budgets; and whether Colorado should have identified a 
separate NOX budget in 1998 (the maintenance year) of 102.7 
tons per day, to maintain consistency with the maintenance 
demonstration. For a more complete description of EPA's request for 
additional comments, please see EPA's August 5, 1997 notice of proposed 
rulemaking at 62 FR 42088.

II. Response to Public Comments

    In this notice, EPA is taking final action and addressing comments 
relating to its October 3, 1996 and August 5, 1997 notices of proposed 
rulemaking. Generally, EPA has addressed comments on each notice 
separately. Where this is not the case, EPA has so indicated.
    A. October 3, 1996 Proposal: The following numbered paragraphs 
contain summaries of the comments received on the October 3, 1996 
notice of proposed rulemaking. Each comment summary is followed by 
EPA's response.
    1. The PM10 budget that the Governor submitted on July 18, 1995 
includes permanent budgets of 54 and 60 tons. However, the Colorado Air 
Quality Control Commission's (AQCC) rule provided that these budgets 
would expire in 1998. Since the legislature did not eliminate the 1998 
expiration of these budgets, rulemaking by the AQCC would have been 
required to eliminate the 1998 expiration. The AQCC did not conduct 
such rulemaking, and therefore, the permanent 54 and 60 ton budgets 
that the Governor submitted are without authority and the notice and 
hearing requirements of the CAA were not met.
    This commentor augmented his comments on this point in response to 
EPA's August 5, 1997 notice, as follows: The legislature did not even 
mention, and therefore did not change or delete, the sunset language 
contained in section C.4. of the AQCC's budget rule. Nor does S.B. 95-
110 specify what the text of the rule shall be or repeal or limit the 
Commission's authority to revise the emission budgets. Because neither 
the legislature nor the AQCC legally amended section C.4. of the rule 
submitted to EPA, section C.4. remains a part of the rule, and EPA must 
approve all or none of the rule. Also, other entities at the State 
level lack authority to submit part of the AQCC's rule and omit other 
parts. Only the AQCC or the legislature, following proper notice and 
hearing procedures, had this authority.
    EPA Response: Contrary to the commentor's assertion, EPA believes 
the Colorado legislature, through its passage of Colorado S.B. 95-110, 
did eliminate the 1998 expiration (or sunset) of the 54 and 60 ton 
budgets. In EPA's view, the legislature specifically eliminated the 
reversion to a 44 ton budget from the SIP revision and designated the 
60 ton budget as the budget that would apply in the future for purposes 
of federal transportation conformity. For example, the language of S.B. 
95-110 reads as follows:

    ``The revisions to the Denver element of the PM10 State 
Implementation Plan adopted by the Commission on February 16, 1995, 
which contain a sixty tons-per-day PM10 mobile source emissions 
budget which expires January 1, 1998, and reverts to a forty-four 
tons-per-day budget, are amended to provide that such forty-four 
tons-per-day reversion shall not be a part of the state 
implementation plan * * * The sixty tons-per-day emissions budget 
shall, unless modified by the Commission through rule-making, apply 
for federal transportation conformity and is included in the State 
Implementation Plan only as required by the federal Act.''

This language makes clear that the legislature intended that there 
would be no reversion to a budget of 44 tons per day. Given this, the 
commentor's reading appears to be inconsistent with the legislative 
intent because such reading would result in the expiration of the 54 
and 60 ton budgets on January 1, 1998 and their replacement with the 44 
ton budget.
    In addition, the legislature was explicit that the 60 ton budget 
should apply for the purposes of federal transportation conformity. The 
commentor reads this directive out of the legislation by focusing (in 
his comments on both of EPA's notices) on the second clause of the 
statute, which states ``and is included in the State Implementation 
Plan only as required by the federal Act.'' The commentor

[[Page 15296]]

interprets this to mean that the legislature left it to the AQCC to 
determine whether a budget was necessary to meet Clean Air Act 
requirements.
    Concluding that no budget is required to meet nonattainment area 
SIP requirements, the commentor concludes that the legislature would 
not have wanted the budget in the SIP. However, EPA believes the better 
reading is that the legislature was indicating that the budget would be 
part of the SIP as necessary for it to be used for federal 
transportation conformity purposes, and that the legislature was not 
leaving it to the AQCC to decide whether the budget was required by the 
CAA. In this regard, it is noteworthy that the legislature used the 
present tense--the 60 ton budget ``is included in the State 
Implementation Plan * * * '' (emphasis added.) Under EPA's conformity 
rule, the budget may not be used unless it is part of a submitted SIP. 
In this sense, there is a mandate in EPA's rule that the budget be part 
of the SIP prior to use for conformity purposes, and it is reasonable 
to read Colorado S.B. 95-110 as mandating the use of the 60 ton budget.
    EPA does not believe the legislature had to specify new rule 
language in order to amend the SIP. The State legislature does not 
adopt rules, and thus, there was no need for the legislature to specify 
replacement rule language. It is also irrelevant that the legislature 
did not repeal or limit the AQCC's authority to revise the emission 
budgets. The legislature was indicating that the 60 ton budget would 
apply unless modified by the AQCC through rulemaking at some future 
date. The legislature was not providing that the 60 ton budget would 
only apply if endorsed by the AQCC through rulemaking.
    Comments submitted by the Colorado Attorney General's Office 
support EPA's reading of the legislation. See February 13, 1997 letter 
signed by Frank Johnson. EPA believes it is reasonable to accord the 
interpretation of the Attorney General's Office some deference given 
that it is State legislation and not federal law that is at issue.
    Although section 25-7-124(1) provides that the AQCC is the 
regulatory entity under Colorado law with authority to adopt SIP 
revisions, EPA believes the legislature retains the authority to adopt 
SIP revisions in a given instance. That is what the legislature did 
through the passage of S.B. 95-110.
    2. Submission of the 54 and 60 ton budgets violates State law 
because State law prohibits submission to EPA of measures not required 
by the CAA. Specifically, C.R.S. sections 25-7-105(1)(a)(III) and 25-7-
105.1(1) prohibit the submission of rules or requirements not required 
by the federal act. Motor vehicle emission budgets are not required by 
the CAA and therefore, the 54 and 60 ton budgets were not lawfully 
submitted to EPA.
    EPA Response: As a preliminary matter, EPA is not convinced that it 
should or can take cognizance of the State's compliance or lack thereof 
with C.R.S. section 25-7-105.1(1). It is well-established in case law 
under the CAA that EPA must approve a SIP submission if it meets the 
minimum requirements of section 110 and other relevant sections of the 
CAA and does not otherwise conflict with the CAA. See, e.g., Union 
Elec. Co. v. E.P.A., 96 S.Ct. 2518 (1976). Even if the State should not 
have submitted the 54 and 60 ton budgets to EPA under State law, 
nothing in C.R.S. section 25-7-105.1(1) suggests that the State will be 
unable to implement or enforce the budgets. Thus, there is no apparent 
conflict with the requirements of section 110(a)(2)(A) or (E) of the 
CAA. To the extent C.R.S. section 25-7-105.1(1) purports to restrict 
what constitutes part of the federally enforceable approved SIP, EPA 
believes the State legislature lacks the authority to amend the 
relevant sections of the CAA and the Administrative Procedures Act with 
respect to SIP approval. The burden is on the State to comply with 
C.R.S. section 25-7-105.1(1), and EPA should not be forced to assume 
that burden. See Union Elec. Co. v. E.P.A., 96 S.Ct. 2518, 2528-2529 
(1976). If the commentor believed the State violated C.R.S. section 25-
7-105.1(1), EPA believes the commentor's recourse would have been to 
challenge the State's submission of the budgets in State court. It is 
not EPA's role to assure compliance with this State law.
    Notwithstanding the foregoing, EPA believes the State legislature 
issued a specific directive in this case that the 60 ton budget would 
apply for purposes of conformity determinations. See EPA's response to 
comment II.A.1., above. Thus, even if the commentor is correct that 
these budgets were not otherwise required by the CAA and thus, normally 
could not have been properly submitted by the State pursuant to C.R.S. 
section 25-7-105.1(1), the legislature had the authority to disregard 
its general restriction on submitting SIPs not required by the CAA (as 
set forth in C.R.S. section 25-7-105.1(1)) and to adopt and require the 
use of the 60 ton budget. In EPA's view, the legislature's specific 
directive regarding the 60 ton budget overrides the more general 
proscription contained in C.R.S. section 25-7-105.1(1).
    3. The motor vehicle emissions budget (MVEB) does not provide for 
attainment of the NAAQS. Specifically, the 60 ton budget will result in 
NAAQS violations at numerous receptor areas unless emissions are 
reduced in those receptor areas below the levels allowed by the 60 ton 
regional budget. The regional budget should reflect the values 
necessary to show attainment in areas where the 60 ton budget would 
result in NAAQS violations. Also, values necessary to show attainment 
for areas that would otherwise violate should be used to establish 
subregional budgets for those areas. The CAA does not allow the 
substitution of future dispersion modeling for the setting of 
appropriate emissions budgets.
    EPA Response: Contrary to the commentor's assertion, the 60 ton 
budget already reflects the necessary emissions reductions to show 
attainment in all of the receptor grids. This is described in the SIP 
itself and the October 19, 1995 Kevin Briggs 1 memo that the 
commentor provided with his comments. According to the Kevin Briggs 
memo, the uncontrolled 2015 scenario would result in mobile source 
emissions of 68 tons per day with NAAQS violations in a number of 
grids. The State reduced emissions sufficiently in the violating grids 
to model attainment in those grids. After making these reductions, the 
State summed the emissions from all grids and arrived at a budget of 60 
tons.
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    \1\ Mr. Briggs is a modeler in the Technical Services Program, 
Air Pollution Control Division, Colorado Department of Public Health 
and Environment.
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    For purposes of responding to the comment, EPA will assume that the 
commentor meant that the State had not adopted control measures in the 
SIP that would achieve the 8-ton reduction (from 68 to 60 tons per day) 
in the violating grids in 2015. The Act clearly requires adopted, 
enforceable control measures as needed to support attainment and 
maintenance demonstrations required by Part D of the Act. However, as 
discussed in the preamble to the recently-adopted revisions to the 
conformity rule (62 FR 43787, August 15, 1997), EPA believes that it 
has the flexibility to approve budgets for years beyond the required 
attainment or maintenance SIP for transportation conformity purposes 
based on less rigorous demonstrations than are required for these SIPs. 
In particular, EPA believes it has the authority to approve budgets for 
years beyond the attainment or maintenance SIP based in

[[Page 15297]]

part on enforceable commitments in the SIP to adopt specific controls 
in the future, or on commitments in the SIP to adopt offsetting 
emission reductions in the future, as necessary to produce the required 
emissions reductions.
    In this case, the MVEB SIP goes beyond a simple commitment to adopt 
any needed controls or reductions in the future, because the 
requirement for dispersion modeling carries with it a mandate for 
adoption of any future controls necessary to provide for attainment of 
the NAAQS. DRCOG must achieve the adoption of or obtain enforceable 
commitments for any control measures necessary to ensure that 
dispersion modeling for each conformity determination shows no 
violations of the NAAQS prior to making a conformity determination. 
This approach to the adoption of controls has two advantages: First, it 
is self-enforcing (if the dispersion modeling shows violations, DRCOG 
cannot adopt transportation plans and TIPs); second, it requires a 
reassessment of control strategies each time a conformity determination 
is carried out, rather than a one-time effort to adopt controls in 
advance which may later become obsolete due to changes in the location 
or magnitude of emissions (and thus, modeled violations). EPA believes 
that the SIP's requirement for dispersion modeling and future adoption 
of necessary controls satisfactorily complies with the policy options 
expressed at 62 FR 43787 for budgets for years beyond the attainment or 
maintenance demonstration, and is approving this requirement and the 60 
ton budget for Denver. EPA would not approve the 60 ton budget for 
Denver without its companion modeling requirement and the associated 
requirement for adoption of controls prior to each conformity 
determination. It should also be noted that the State commits in the 
SIP to adopt any control measures relied on for future conformity 
determinations into the SIP if necessary to demonstrate continued 
maintenance of the standard. See EPA's response at II.A.4., below.
    The commentor is correct that the State did not establish 
subregional budgets. However, EPA's regulations do not require that an 
area establish subregional budgets. The preamble to EPA's November 24, 
1993 conformity rule states, ``The SIP may specify emissions budgets 
for subareas of the region, provided that the SIP includes a 
demonstration that the subregional emissions budget, when combined with 
all other portions of the emissions inventory, will result in 
attainment and/or maintenance of the standard.'' 58 FR 62196 (emphasis 
added.) This language makes clear that the establishment of subregional 
budgets is optional.
    Regarding the use of dispersion modeling, EPA agrees that the Act 
precludes the use of dispersion modeling as a substitute for an 
emissions budget test. However, EPA's conformity rule did not 
anticipate situations where a regional dispersion modeling analysis 
would be used in addition to an emissions budget test. EPA does not 
believe that such an application of dispersion modeling is precluded by 
either the Act or the conformity rule. As a practical matter, 
dispersion modeling in conjunction with an emissions test is at least 
as protective as establishing and using subregional budgets, because in 
dispersion modeling a certain target level of emissions has to be met 
in each grid in order for each grid to show attainment.2 
Even if subregional budgets were adopted, it is quite likely that they 
would not be developed for each grid. In such a case, it might be 
possible to show conformity using subregional budgets in cases when it 
would not be possible using dispersion modeling.
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    \2\ In this case, the SIP requires that the Denver Regional 
Council of Governments (DRCOG) support each conformity determination 
with a dispersion modeling analysis that shows that each grid in the 
modeling domain will be in attainment, considering the emissions 
expected from implementation of the transportation plan or 
Transportation Improvement Program (TIP). If the modeling analysis 
shows that emissions reductions are needed in any locations in order 
to provide for future maintenance of the NAAQS, it is incumbent upon 
DRCOG to identify and ensure implementation of any measures needed 
to provide those reductions. Thus, DRCOG must satisfy two tests to 
demonstrate conformity: Compliance with the 60 ton budget, and a 
dispersion modeling analysis showing no violations.
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    The requirement for dispersion modeling in addition to a budget 
test is certainly more protective of the NAAQS than the budget-only 
process envisioned by the conformity rule. The conformity rule only 
requires the identification of and compliance with a region-wide 
budget. It is conceivable that an area could show conformity to a 
region-wide budget and still have localized violations of the NAAQS 
because growth in emissions occurs in different areas than anticipated. 
In a dispersion modeling approach, these same localized violations of 
the NAAQS would preclude a conformity finding.
    In summary, the SIP's requirement for a region wide budget in 
combination with dispersion modeling clearly meets the minimum 
requirements of the conformity rule, and is at least as protective of 
the NAAQS as subregional budgets would be.
    This commentor also included comments indicating that the PM10 SIP 
does not include necessary and/or enforceable control measures that 
will lead to attainment and maintenance of the NAAQS. In particular, 
the commentor indicated that VMT growth was higher than the SIP 
anticipated and that the SIP contained no measures to ensure VMT would 
remain at the SIP-anticipated levels. EPA responded to these comments 
when it approved the PM10 SIP and will not repeat the comments or 
responses here. See 62 FR 18716 (April 17, 1997). For purposes of this 
notice, EPA would add that it does not believe Congress intended, 
through section 176 of the CAA, to change the way in which States must 
conduct attainment or maintenance demonstrations. As noted in the April 
1997 notice, EPA believes that it may allow a reasonable margin of 
error for VMT estimates in attainment and maintenance demonstrations, 
and EPA concludes that no different result should be required for 
purposes of establishing conformity-related motor vehicle emissions 
budgets. It should also be noted that any increased VMT will have to be 
taken into account in any future conformity determinations, and will 
ultimately make it harder to demonstrate conformity.
    4. The submitted MVEB unlawfully attempts to transfer authority to 
adopt and implement control measures. The commentor objects to the 60 
ton budget because the SIP gives DRCOG the responsibility for 
identifying any necessary controls to achieve emission reductions 
needed to demonstrate conformity. The commentor believes that this is a 
delegation of responsibility from the AQCC to DRCOG, in violation of 
the Act and State law. The commentor further states that any such 
controls are without legal authority and may not be treated as part of 
the SIP or be given emissions reduction credit for purposes of 
conformity.
    EPA Response: EPA's conformity rule envisions situations where 
regulatory and non-regulatory control measures may be needed to provide 
emissions reductions for a conformity determination. Here, the AQCC is 
not delegating its authority to adopt control measures, only to 
identify them. If any measures identified as necessary by DRCOG require 
a State regulation in order to be implemented (for example, a revision 
to the I/M or oxygenated fuels program regulations), the AQCC would 
still need to adopt such regulation or regulation revision pursuant to 
applicable State law, or meet one of the other requirements in 40 CFR 
93.122(a)(3), before DRCOG could take

[[Page 15298]]

credit for these emissions reductions in its conformity determination.
    However, the conformity rule does not require all regulatory 
control measures needed for a conformity determination to be 
incorporated into the SIP, as the commentor asserts. Also, not all 
control measures for conformity purposes require a regulation in order 
to be implemented, such as changes in localized street sanding and 
sweeping practices. EPA is satisfied with DRCOG's current practice of 
obtaining commitments from local entities to implement non-regulatory 
control measures and incorporating these commitments into its 
conformity determinations, just as it obtains commitments from local 
entities to implement transportation improvement projects during the 
time frame of the plan and TIP.
    It is also worth noting that the SIP, at page XI-9, states, ``Any 
control measure relied on for a conformity determination shall be 
included in a revised attainment or maintenance SIP unless it is not 
necessary to demonstrate attainment or maintenance of the standard.'' 
EPA views this as a commitment on the part of the State to adopt any 
measures which are necessary to show continued attainment and 
maintenance of the standard.
    5. The mobile source emissions budgets will ensure that future 
regional transportation plans and programs will continue to help the 
region attain and maintain the PM10 standard. Additionally, the budgets 
are entirely consistent with the conformity provisions of the Clean Air 
Act Amendments of 1990 and EPA guidance.
    EPA Response: EPA agrees that the budgets are consistent with the 
CAA's conformity requirements.
    6. Enforceable budgets that would have reduced emissions volumes in 
the region were agreed to in February 1995, but the intercession by the 
legislature reduced these to little more than a suggestion.
    EPA Response: EPA agrees that the legislature changed the PM10 
budgets. However, EPA believes the budgets are consistent with the 
requirements of the CAA and EPA's conformity rule, as described in more 
detail above.
    B. The Colorado Attorney General's Office submitted comments in a 
letter dated February 13, 1997, signed by Frank Johnson, Assistant 
Attorney General, that respond to several of the comments described in 
Section II.A., above. The following numbered paragraphs contain 
summaries of the relevant comments from Mr. Johnson's February 13, 1997 
letter. Each comment summary is followed by EPA's response.
    1. The Colorado legislature amended the SIP to eliminate the 
reversion to a 44 ton PM10 budget and to specify a 60 ton PM10 budget. 
The language of C.R.S. section 25-7-105(1)(a)(III) itself and the 
legislative history of the statute indicate that the legislature 
intended a 60 ton PM10 budget to apply for purposes of federal 
conformity. Thus, no further rulemaking action by the AQCC was 
necessary.
    EPA Response: EPA agrees with this interpretation of C.R.S. section 
25-7-105(1)(a)(III) and believes the interpretation is entitled to 
deference.
    2. The references to the 60 ton budget in C.R.S. section 25-7-
105(1)(a)(III) include the smaller emissions budgets for the years 
before the 60 ton budget applies. The Colorado legislature used ``sixty 
tons-per-day emissions budget'' as a shorthand to describe the interim 
budgets that apply before 2006 and the 60 ton budget that applies in 
2006 and after. The legislature eliminated the provision of the budgets 
that contained the expiration of the higher budgets and reversion to 44 
tons; the legislature did not intend to change the structure of interim 
budgets leading to a 60 ton budget in 2006.
    EPA Response: Although the statute could have been drafted more 
clearly, EPA believes the interpretation of the Attorney General's 
Office is reasonable and is entitled to deference. Therefore, EPA 
concludes that the statute should be interpreted consistent with the 
letter submitted by the Attorney General's Office.
    3. No further rulemaking by the AQCC was necessary to eliminate the 
expiration of the 60 ton budget. A contrary reading would lead to the 
result that the 44 ton budget would apply starting in 1998 when the 
legislature clearly did not want this to happen. The legislature made 
clear that the 44 ton reversion would only apply for purposes of state 
law.
    EPA Response: EPA agrees with this interpretation and believes it 
is entitled to deference.
    4. No further public hearings by the AQCC were necessary following 
the Colorado legislature's amendment of the budgets. In addition, no 
notice and hearing were required before the legislature itself. The 
adoption of the SIP by the AQCC in February 1995 and the amendment of 
the SIP by the legislature in May 1995 were steps in the process of 
developing a single SIP revision. Nothing in EPA's rules requires 
additional hearings at subsequent steps in the state review process. In 
addition, the legislative process is open and public and the 
legislators are accountable to the electorate.
    EPA Response: EPA responds to these comments in Section II.C., 
below.
    5. State statutes do not prohibit the submission of the 60 ton 
budget for inclusion in the SIP. Other commentors' reading of C.R.S. 
section 25-7-105(1)(a)(III) is not consistent with legislative intent. 
When the Colorado legislature said the 60 ton budget ``is included in 
the SIP only as required by the federal act'', the legislature meant 
that the budget is included in the SIP only as required in order for 
such emissions budget to apply for the purposes of transportation 
conformity. Commentors' reading would negate the 60 ton budget and 
result in the application of the 44 ton budget, something the 
legislature clearly did not intend. The argument that C.R.S. section 
25-7-105.1 prohibits the inclusion of the 60 ton budget in the SIP 
because it is not required by the CAA or EPA regulations also fails. 
The specific provisions of 25-7-105(1)(a)(III), that indicate the 60 
ton budget will apply for federal transportation conformity, control 
over the more general provisions of 25-7-105.1.
    EPA Response: See EPA's response to comment II.A.2 above. In 
addition, EPA believes the interpretation of the Attorney General's 
Office is entitled to deference on this question of State law.
    C. August 5, 1997 Notice: Procedural Issues. Comments on the 
October 3, 1996 notice of proposed rulemaking raised concerns about the 
process the State followed in adopting the PM10 budget. EPA sought 
additional comment on the question whether the State met the CAA's 
notice and public hearing requirements in adopting the PM10 budget. The 
following numbered paragraphs contain summaries of the comments 
received on the August 5, 1997 notice of proposed rulemaking that are 
related to the notice and public hearing issue. EPA's response follows 
the last comment summary related to this issue.
    1. Hearings held by the AQCC were adequate to satisfy the CAA's 
notice and hearing requirements. The hearings before the AQCC and the 
subsequent action by the General Assembly should be viewed as a single 
process that led to the adoption of the PM10 budgets SIP. There was no 
requirement to hold additional hearings before the General Assembly. 
The General Assembly was well aware there were parties opposed to the 
adoption of the 60 tons-per-day emission budget.
    2. The legislative process is open and public and the legislators 
are

[[Page 15299]]

accountable to the electorate. The General Assembly provided an 
opportunity for public input through a public hearing before a 
committee of reference and public debate on the floor of each house. 
Environmental groups were actively involved in the debate. In addition, 
the public was on notice that the PM10 budgets SIP would be subject to 
review by the legislature as provided by section 25-7-133(1), C.R.S. 
Therefore, the legislative session itself complied with the notice and 
hearing requirements for adoption of the SIP.
    3. There was no need for the AQCC to hold a public hearing to 
confirm actions taken by the General Assembly.
    4. The adequacy of the legislative process with regard to 
satisfying the public hearing requirement of section 110 of the CAA and 
40 CFR 51.102 is irrelevant. The legislature, when it passed S.B. 95-
110, left discretion with the AQCC to determine the appropriate budget 
to submit to EPA. (EPA describes and responds to this comment on this 
issue in Sections II. A. and B., above, and will not respond further in 
this section.)
    5. If EPA decides that the legislature mandated the PM10 budget as 
submitted, the legislature did not satisfy the requirements of 40 CFR 
51.102 for notice and hearing. In addition, notice and hearing granted 
by the AQCC did not satisfy the requirement for notice and hearing 
before the legislature.
    EPA Response: It has been particularly difficult for EPA to reach a 
decision on this issue. EPA takes very seriously the CAA's notice and 
public hearing requirements and believes that legitimate questions have 
been raised regarding the process the State followed in adopting the 
PM10 budget SIP. On balance, however, EPA agrees with the commentors 
who asserted that notice and public hearing before the AQCC in February 
1995 satisfied the notice and hearing requirements of the CAA and EPA's 
regulations. 3 Although the General Assembly reached a 
different result than the AQCC, relevant issues regarding the 
appropriate size and applicability of the PM10 budgets were aired in 
the hearing before the AQCC, and the budgets the General Assembly 
ultimately adopted appear to be a logical outgrowth of the hearing 
before the AQCC. As noted by one of the commentors, following the 
AQCC's February 1995 hearing, the AQCC could have adopted the same 
budgets the General Assembly ultimately adopted. Therefore, EPA 
concludes that the budget established in the SIP was the result of 
adequate notice and hearing.
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    \3\ These notice and public hearing requirements can be found in 
section 110(a)(2) of the CAA, 42 U.S.C. section 7410(a)(2), and 40 
CFR 51.102.
---------------------------------------------------------------------------

    In finding that notice and public hearing were adequate in this 
case, EPA wants to make two points. First, EPA is finding that the 
process the State followed satisfied the minimum requirements for 
notice and public hearing for purposes of Clean Air Act requirements 
and EPA regulations; EPA is not making a finding that the State process 
was ideal or should necessarily serve as a model for future actions. 
Second, EPA wants to make it clear that legislative amendment of AQCC 
rulemaking may not always satisfy the CAA's notice and hearing 
requirements. EPA believes the legislative action must bear some 
logical relationship to the notice and public hearing previously 
concluded before the rulemaking agency, or the notice and public 
hearing requirement must be satisfied by the legislature itself or by 
subsequent administrative action.
    As a prudential matter, EPA would recommend that the State take 
steps to optimize public participation so that this type of issue does 
not arise in the future. For example, although more than one commentor 
suggested the General Assembly was aware of opposition to the 60 ton 
budget, none of the commentors indicated whether the General Assembly 
or relevant committees thereof actually considered the testimony and 
evidence presented to the AQCC; EPA believes it would be prudent to 
insure that they do so in the future.
    EPA does not agree with those commentors who assert that the 
legislative action standing alone met EPA's notice and public hearing 
requirements. EPA's regulations are quite specific in their 
requirements. Among other things, 30 days prior notice is required. See 
40 CFR 51.102. No commentor has suggested that the legislature or one 
of its committees complied with this requirement. Also, EPA does not 
agree with the commentor who asserts that C.R.S. section 25-7-133(1) 
satisfied the CAA's notice requirements, in particular since prior to 
the General Assembly's adoption of the PM10 budget SIP, this statute 
only provided for the General Assembly to accept or reject a SIP 
revision adopted by the AQCC, rather than alter the budget SIP as was 
done in this case.
    Because EPA concludes that the CAA's notice and hearing 
requirements were met in this case, EPA agrees with the commentors who 
asserted there was no need for the AQCC to hold an additional hearing 
after the General Assembly had acted. However, it is conceivable that 
further notice and hearing before the AQCC would have been one way for 
the State to satisfy EPA's notice and public hearing requirements if 
the February 1995 AQCC hearing had not been sufficient for this 
purpose. Another way would have been for the General Assembly itself to 
comply with EPA's notice and hearing requirements.
    Regarding one commentor's assertion that notice and hearing 
requirements were met because environmental groups were actively 
involved in the debate regarding the PM10 budgets SIP within the 
General Assembly, EPA was unable to substantiate this claim through any 
materials submitted by commentors or through independent research. 
However, EPA's research revealed that several other parties, including 
the AQCC's hearing officer for this SIP, did provide testimony before 
the Legislative Council and/or a committee of reference.
    D. August 5, 1997 Notice: Substantive Issues. EPA received comments 
on its October 3, 1996 notice of proposed rulemaking that raised 
concerns regarding the adequacy of the emissions budgets. Based on 
these comments, EPA concluded that it needed additional input from 
commentors in order to make an informed decision. Thus, in its August 
5, 1997 notice, EPA sought additional comment regarding the following 
two issues: (1) Whether it was appropriate for the budget SIP to 
include a single NOX budget from the 1995 attainment 
demonstration of 119.4 tons per day when the maintenance demonstration 
NOX emissions inventory was 102.7 tons per day, and (2) 
whether potential growth in non-mobile sources was adequately 
considered in setting the emissions budgets for years beyond the PM10 
SIP attainment and maintenance years. The numbered paragraphs below 
contain summaries of the comments received on these issues. For each 
issue, EPA's response follows the last comment summary for the 
particular issue. EPA has noted where the comment summary includes 
comments on the October 3, 1996 notice.
    Issue 1: Whether it was appropriate for the budget SIP to include a 
single NOX budget of 119.4 tons per day when the maintenance 
demonstration NOX emissions inventory was 102.7 tons per 
day.

Comment Summaries

    1. EPA's analysis of this issue in its August 5, 1997 notice was 
correct. The NOX emissions budget of 119.4 tons per day is 
consistent with the available safety margin, and therefore need not 
conform to the inventory in the maintenance demonstration.

[[Page 15300]]

    2. The analysis of the 60 ton PM10 budget assumed NOX 
emissions of 119.4 tons per day. This analysis showed that the area 
would continue to attain the standard with these emissions values. 
Thus, the maintenance year emissions of NOX are irrelevant.
    3. Under EPA's conformity rule, projections of emissions in an 
attainment SIP beyond the attainment year are not considered emissions 
budgets unless the SIP explicitly states such an intent. The SIP states 
no such intent.
    4. EPA should consider the fact that the Denver area has not 
violated the PM10 standard in nearly five years and the highest 
recorded value in 1996 was well below the standard. Also, EPA's 
promulgation of a new standard for PM10 may soon render these budget 
and conformity issues moot.
    5. Contrary to EPA's analysis in its August 5, 1997 notice, the 
NOX mobile source emissions budget is based on motor vehicle 
emission estimates in the Denver PM10 SIP, and not a margin of safety. 
The AQCC did not adopt a margin of safety analysis in the SIP which is 
why the analysis was not submitted by the State as part of the SIP 
submission. The NOX budget submitted by the State offers no 
basis for the rationale offered by EPA in its August 5, 1997 notice. 
The conformity rule provides that transportation agencies may not infer 
additions to budgets not explicitly intended by the SIP; the same rule 
must apply to EPA. The SIP must quantify the amount by which motor 
vehicle emissions could be higher while still allowing a demonstration 
of maintenance and must specifically indicate that the excess emissions 
are to be allocated to the MPO for transportation conformity purposes. 
The SIP did not meet either of these requirements. In fact, in the 
maintenance year there are no excess emissions to allocate. The RAQC 
staff's analysis, which EPA cites in its August 5, 1997 notice, does 
not consider emissions from all sources and does not require that 
emissions be distributed to all grid receptors. The maintenance 
demonstration approved by the AQCC and submitted as part of the PM10 
SIP that EPA has approved shows that motor vehicle NOX 
emissions must be no higher than 102.7 tons in order to demonstrate 
maintenance. The RAQC staff's analysis shows that more emissions could 
be added in portions of the Metro area not yet developed, but it 
provides no basis for concluding that more emissions can safely be 
added where vehicle travel is currently occurring. Since the SIP does 
not restrict emissions to the undeveloped portions of the Metro area, 
there is no basis to conclude there are excess emissions to be 
allocated and there is no basis to rely on the RAQC staff's analysis. 
Adding 17 additional tons of NOX in the developed portions 
of the Metro area in the maintenance year would cause estimated 
concentrations to exceed the NAAQS. In addition, the RAQC staff's 
analysis was never officially adopted by anyone. We reiterate comments 
made on the October 3, 1996 proposal that EPA approve the 119.4 ton per 
day budget as the applicable budget only for analyses performed up to 
the attainment year, and that EPA clarify that the applicable budget 
after the attainment year is the NOX estimate contained in 
the maintenance demonstration portion of the approved SIP.
    This same commentor also indicated in comments on EPA's October 3, 
1996 notice of proposed rulemaking that the use of a 119.4 tons per day 
NOX emission budget for years after the attainment year 
would not be consistent with the obligation to set an emission budget 
consistent with the demonstration of maintenance. In those comments, 
the commentor cited to the preamble statement in EPA's November 24, 
1993 conformity rule that, ``[i]n all situations, the emissions budget 
in the SIP must be consistent with the attainment or maintenance 
demonstration * * *'' Because the 119.4 ton budget is not consistent 
with the 102.7 ton inventory in the maintenance year, the commentor 
argued that the appropriate NOX budget would be 119.4 tons 
per day NOX up to the attainment year, but would be 102.7 
tons per day NOX beyond the attainment year. EPA Response: 
In its August 5, 1997 supplemental notice, EPA proposed approval of the 
PM10 and NOX budgets for Denver based in part on the safety 
margin analysis conducted by the RAQC. This analysis sought to 
demonstrate that mobile source emissions in the Denver modeling region 
could be as high as 221 tons per day of PM10 before violations of the 
NAAQS would occur. After reviewing all of the comments and carefully 
considering the requirements of the conformity rule and the Act, EPA 
has determined that it can no longer endorse the RAQC's suggested 
approach for defining a safety margin.
    The conformity rule, as amended on August 15, 1997, defines safety 
margin as the amount by which the total projected emissions from all 
sources of a given pollutant are less than the total emissions that 
would satisfy the applicable requirement for reasonable further 
progress, attainment or maintenance of the relevant air quality 
standard. For example, many maintenance plans include maintenance year 
emission inventories which are lower than the attainment year 
inventory. The difference between these two levels of emissions could 
be considered a margin of safety. Some attainment SIPs are submitted 
with modeled attainment values which are somewhat below the standard; 
the difference in emissions between the SIP level and the level that 
would just provide for attainment of the standard could be considered a 
safety margin.
    However, the RAQC's analysis is based on maximizing emissions in 
all grids in the modeling domain, and as such is more of a ``carrying 
capacity'' analysis. It bears no relation to the attainment or 
maintenance year emission inventory; emissions in all portions of the 
modeling domain were increased to levels equivalent to downtown Denver, 
including remote rural regions, even though activity levels in the 
remote grids in the attainment or maintenance year were not high enough 
to create such emissions levels. The RAQC's approach to establishing a 
safety margin would appear to conflict with the requirements of section 
176(c)(2)(A) of the CAA.
    It would have been more appropriate to calculate a safety margin 
for Denver by determining the difference in emissions between the 
modeled 1995 attainment value (147.7 ug/m3) and the standard of 150 ug/
m3, by proportionally increasing the 1995 inventory used in the 
modeling until the standard had been reached. A safety margin 
calculated in this way would likely only amount to a few tons per day. 
However, the RAQC did not calculate its safety margin this way, and EPA 
has decided it cannot rely on the RAQC's analysis for purposes of this 
action, nor is EPA generally endorsing this approach for the 
establishment of safety margins in other nonattainment or maintenance 
areas. Thus, EPA is not relying on the RAQC's safety margin analysis to 
justify approval of the 119.4 tons per day NOX budget.
    In addition, EPA finds unconvincing the argument that 1998 
projections of NOX emissions would not be a budget for 
conformity purposes unless the SIP states explicitly states such an 
intent. The conformity rule is clear that approved attainment and 
maintenance demonstrations and any required milestone demonstrations 
establish budgets which must be used for conformity until superseded by 
subsequent approved SIPs for those same years. In this case, the PM10 
SIP's 1998 maintenance demonstration was

[[Page 15301]]

required by section 189(c) of the CAA; i.e., it was a required 
milestone. EPA notes that the State did establish a 1998 PM10 budget, 
and that 1998 PM10 budgets have been established for other PM10 
nonattainment areas within the State of Colorado. Also, EPA does not 
agree with the approach of establishing a budget for one precursor of 
PM10 for any given year, but not all of them. Since the PM10 and 
NOX inventories work in tandem as part of the attainment and 
maintenance demonstrations in Denver, it does not make technical sense 
to regulate one pollutant through conformity but not the other. The 
conformity rule is clear that these inventories are to be treated as 
budgets for purposes of conformity; a state may not evade this 
requirement by merely declaring an intent that a required attainment, 
maintenance or milestone inventory for a pollutant or pollutant 
precursor is not to be considered a budget. The conformity rule 
language cited by the commentors in asserting that the 1998 
NOX budget is not to serve as a budget refers to optional 
projections of emissions in SIPs that are not otherwise required by the 
Act or EPA SIP policy. In this case, both PM10 and NOX motor 
vehicle emissions inventories were required as part of the maintenance/
milestone demonstration in the PM10 SIP.
    However, EPA notes that the NOX budget of 119.4 tons per 
day from the 1995 attainment demonstration was used in the modeling 
analysis which the APCD used in adopting the 60 ton PM10 budget. EPA 
also notes that projected NOX emissions from the 
transportation plan and TIP (not to exceed the adopted budget of 119.4 
tons per day) are required to be used in the dispersion modeling 
conducted for each conformity determination. Therefore, since the 
budgets and their associated dispersion modeling requirement will 
provide for maintenance of the NAAQS, as discussed in section II. A. 
3., above, EPA is also approving the 119.4 tons per day NOX 
budget for all future years. EPA views the latest submission which 
relied on this analysis as setting the valid budget for this period for 
transportation conformity purposes, which is today approved into the 
SIP.
    Finally, as noted by one commentor, EPA promulgated a revised PM10 
NAAQS on July 18, 1997. (See 62 FR 38652.) Specifically, the form of 
the NAAQS was revised in a way that makes the standard less stringent 
overall. As a result of the promulgation of the new PM10 NAAQS, EPA may 
in the near future revoke the old PM10 NAAQS for Denver. However, EPA 
has not yet decided whether conformity requirements will continue to 
apply to areas for which the old PM10 NAAQS has been revoked and for 
which no new nonattainment designation has been made. Furthermore, the 
old PM10 NAAQS has not yet been revoked for Denver. Therefore, the 
budgets are not moot, and the mere possibility that the new NAAQS may 
render the budgets moot is not relevant to EPA's decision to approve 
the budgets. Also, the fact that the area has been attaining the PM10 
NAAQS, while providing an extra measure of comfort regarding the 
attainment and maintenance/milestone demonstrations in the PM10 SIP, 
does not by itself provide an adequate technical basis for EPA to 
approve the budgets.
    Issue 2: Whether potential growth in non-mobile sources was 
adequately considered in setting the emissions budgets for years beyond 
the PM10 SIP attainment and maintenance years.

Comment Summaries

    1. As EPA noted in its August 5, 1997 notice, the conformity rule 
does not require consideration of growth in non-mobile sources each 
time a conformity determination is made. EPA's analysis in its August 
5, 1997 notice is consistent with the application of conformity 
requirements in nonattainment areas throughout the country. Further, 
the conformity rule does not require the mobile source sector to offset 
projected growth in emissions from non-mobile sources.
    2. No growth in non-mobile sources is expected over the next 20 
years. Thus, growth in non-mobile sources is a non-issue. This 
commentor submitted data to support this assertion.
    EPA Response: In addition to the comments received above, the 
preamble to EPA's August 15, 1997 amended conformity rule is relevant 
to this question and EPA has considered the preamble language in 
addressing this issue.
    In conducting the modeling that led to the establishment of the 60 
ton budget, APCD held all non-mobile sources (and mobile source 
NOX) constant at 1995 levels. There was concern that the 60 
ton budget would not provide for attainment if non-mobile source 
emissions were to increase in future years.
    Normally, EPA would not approve a budget that had been established 
without considering growth in all source categories. The Act and EPA 
policy are clear that attainment and maintenance SIPs must consider 
growth in all sources in demonstrating attainment or maintenance of the 
NAAQS, and the conformity rule's budget test relies on the fact that 
SIP budgets do consider growth in all sources to ensure that 
transportation plans, programs and projects will not cause or 
contribute to violations of the NAAQS. The preamble to EPA's August 15, 
1997 conformity rule establishes that growth in non-mobile sources must 
be considered in setting motor vehicle emission budgets for years 
beyond the attainment or maintenance demonstration (62 FR 43787-
43788).4
---------------------------------------------------------------------------

    \4\ A number of commentors indicated that the conformity rule 
does not require consideration of growth in non-mobile sources for 
conformity determinations. This is accurate but should be 
distinguished from the initial setting of motor vehicle emission 
budgets in SIPs. The preamble to EPA's August 15, 1997 conformity 
rule is clear that growth in non-mobile sources must be considered 
in setting ``out-year'' budgets. 62 FR 43787-43788.
---------------------------------------------------------------------------

    However, in response to EPA's request for public comment, the RAQC 
submitted documentation indicating there will be no growth in non-
mobile sources at any time in the near future. The RAQC has been 
working since 1995 on development of a long-range air quality plan 
known as the Blueprint for Clean Air for PM10 and two other pollutants. 
As part of this plan, long-term projections of emissions from all 
source categories have been developed by the RAQC and the State Air 
Pollution Control Division. The information submitted to the docket for 
this rulemaking by the RAQC demonstrates that non-mobile sources will 
remain below 1995 levels through at least the year 2020, and will be 
approximately 5 percent below 1995 levels in 2020.
    Since it does not appear that there will be any growth in non-
mobile sources in the Denver area over the time period for which the 
budgets were analyzed, EPA is approving the MVEB even though growth in 
these sources was not assessed for purposes of developing and adopting 
the MVEB.
    In its August 5, 1997 supplemental notice, EPA proposed to approve 
the budgets in part based on a safety margin analysis prepared by the 
RAQC. In its analysis, EPA noted that the calculated safety margin of 
221 tons per day of PM10 in 2015 was developed assuming 2015 levels of 
non-mobile source emissions; i.e., growth, or lack thereof, in non-
mobile source emissions had been factored into the calculation of the 
so-called safety margin. As described above, EPA no longer believes the 
RAQC characterization of safety margin is consistent with the CAA or 
the conformity rules. Therefore, EPA is not relying on the RAQC safety 
margin analysis in approving the budgets.

[[Page 15302]]

III. Final Action

    EPA is approving the Denver PM10 and NOX mobile source 
emissions budget SIP revisions submitted by the Governor of Colorado on 
July 18, 1995 and April 22, 1996 respectively as revisions to the 
Colorado SIP. The revisions were submitted in order that they could be 
used to assess the conformity of transportation plans, transportation 
improvement programs and, where appropriate, federally funded projects 
for applicable periods prescribed under conformity requirements within 
the Denver PM10 nonattainment area.
    The current and future year mobile source emissions budgets that 
comprise part of these SIP revisions are as follows:

PM10: 54 tons per day, for analysis years 1998-2005
60 tons per day, for analysis years 2006 and beyond
NOX: 119.4 tons per day, for analysis years 1998 and 
beyond

These budgets are applicable to the PM10 SIP modeling domain.
    For these pollutants, these budgets supersede any prior budgets for 
the Denver PM10 nonattainment area for the same time frames. The 
metropolitan planning organization for the Denver PM10 nonattainment 
area will have to demonstrate conformity to these budgets within 18 
months of EPA's approval of these budget SIPs, in accordance with 40 
CFR 93.104(e)(3).
    It should be noted that, in addition to the budgets themselves, the 
SIP revisions that EPA is approving today contain other provisions that 
must be followed in making transportation conformity determinations 
within the Denver PM10 nonattainment area. These provisions include, 
but are not necessarily limited to, descriptions of relevant inventory 
categories, definitions of applicability, and requirements related to 
dispersion modeling.

IV. Administrative Requirements

A. Executive Order 12866

    The Office of Management and Budget (OMB) has exempted this 
regulatory action from E.O. 12866 review.

B. Regulatory Flexibility Act

    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA 
must prepare a regulatory flexibility analysis assessing the impact of 
any proposed or final rule on small entities. 5 U.S.C. 603 and 604. 
Alternatively, EPA may certify that the rule will not have a 
significant impact on a substantial number of small entities. Small 
entities include small businesses, small not-for-profit enterprises, 
and government entities with jurisdiction over populations of less than 
50,000.
    SIP approvals under section 110 and subchapter I, part D of the 
Clean Air Act do not create any new requirements but simply approve 
requirements that the State is already imposing. Therefore, because the 
Federal SIP approval does not impose any new requirements, the 
Administrator certifies that it does not have a significant impact on 
any small entities affected. Moreover, due to the nature of the 
Federal-State relationship under the CAA, preparation of a flexibility 
analysis would constitute Federal inquiry into the economic 
reasonableness of state action. The Clean Air Act forbids EPA to base 
its actions concerning SIPs on such grounds. Union Electric Co. v. U.S. 
EPA, 427 U.S. 246, 255-66 (1976); 42 U.S.C. 7410(a)(2).

C. Unfunded Mandates

    Under Section 202 of the Unfunded Mandates Reform Act of 1995 
(``Unfunded Mandates Act''), signed into law on March 22, 1995, EPA 
must prepare a budgetary impact statement to accompany any proposed or 
final rule that includes a Federal mandate that may result in estimated 
costs to State, local, or tribal governments in the aggregate; or to 
private sector, of $100 million or more. Under Section 205, EPA must 
select the most cost-effective and least burdensome alternative that 
achieves the objectives of the rule and is consistent with statutory 
requirements. Section 203 requires EPA to establish a plan for 
informing and advising any small governments that may be significantly 
or uniquely impacted by the rule.
    EPA has determined that the approval action promulgated does not 
include a Federal mandate that may result in estimated costs of $100 
million or more to either State, local, or tribal governments in the 
aggregate, or to the private sector. This Federal action approves pre-
existing requirements under State or local law, and imposes no new 
requirements. Accordingly, no additional costs to State, local, or 
tribal governments, or to the private sector, result from this action.

D. Submission to Congress and the General Accounting Office

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Act of 1996, generally provides 
that before a rule may take effect, the agency promulgating the rule 
must submit a rule report, which includes a copy of the rule, to each 
House of Congress and to the Comptroller General of the United States. 
EPA will submit a report containing this rule and other required 
information to the U.S. Senate, the U.S. House of Representatives, and 
the Comptroller General of the United States prior to publication of 
the rule in the Federal Register. This rule is not a ``major rule'' as 
defined by 5 U.S.C. 804(2).

E. Petitions for Judicial Review

    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by June 1, 1998. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this rule for the purposes of judicial 
review nor does it extend the time within which a petition for judicial 
review may be filed, and shall not postpone the effectiveness of such 
rule or action. This action may not be challenged later in proceedings 
to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Hydrocarbons, 
Incorporation by reference, Intergovernmental relations, Nitrogen 
dioxide, Particulate matter, Reporting and recordkeeping requirements, 
Sulfur oxides, Volatile organic compounds.

    Dated: February 26, 1998.
William P. Yellowtail,
Regional Administrator, Region VIII.
    40 CFR part 52 is amended as follows:

PART 52--[AMENDED]

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart G--Colorado

    2. Section 52.320 is amended by adding paragraphs (c)(84) to read 
as follows:


Sec. 52.320  Identification of plan.

* * * * *
    (c) * * *
    (84) The Governor of Colorado submitted the Denver PM10 mobile 
source emissions budget State Implementation Plan (SIP) with a letter 
dated July 18, 1995. The Governor submitted the Denver NOX 
mobile source emissions budget State Implementation Plan (SIP) with a 
letter dated April 22, 1996. The PM10 and NOX mobile source 
emissions budgets and other provisions in these SIP

[[Page 15303]]

submittals are used to assess conformity of transportation plans, 
transportation improvement programs, and transportation projects.
    (i) Incorporation by reference.
    (A) Colorado Air Quality Control Commission, ``Ambient Air Quality 
Standards'' regulation 5CCR 1001-14, Section A.1. Budgets for the 
Denver Nonattainment Area (Modeling Domain) PM10, Sections A.2. and 
A.3., and Sections B and C, adopted on February 16, 1995, effective 
April 30, 1995, as amended by the Colorado General Assembly through 
enactment of Colorado Senate Bill 95-110, which Bill was enacted on May 
5, 1995 and signed by the Governor of Colorado on May 31, 1995. (See 
paragraph (c)(84)(i)(B) of this section).
    (B) Colo. Rev. Stat. section 25-7-105(1)(a)(III), enacted by the 
Colorado General Assembly on May 5, 1995 as part of Colorado Senate 
Bill 95-110 and signed by the Governor of Colorado on May 31, 1995.
    (C) Colorado Air Quality Control Commission ``Ambient Air Quality 
Standards'' regulation 5CCR 1001-14, Section A.1. Budgets for the 
Denver Nonattainment Area (Modeling Domain) Nitrogen Oxides, as adopted 
June 15, 1995, effective August 30, 1995.

[FR Doc. 98-8214 Filed 3-30-98; 8:45 am]
BILLING CODE 6560-50-P