[Federal Register Volume 59, Number 66 (Wednesday, April 6, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8228]


[[Page Unknown]]

[Federal Register: April 6, 1994]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[CO32-1-5982; FRL-4855-7]

 

Clean Air Act Approval and Promulgation of PM-10 Implementation 
Plan for Colorado

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rulemaking.

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SUMMARY: In this action, the EPA proposes approval of the State 
implementation plan (SIP) submitted by the State of Colorado for the 
purpose of bringing about the attainment of the national ambient air 
quality standards (NAAQS) for particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers (PM-10). The 
SIP was submitted by the State on May 27, 1993 to satisfy certain 
federal Clean Air Act requirements for an approvable moderate 
nonattainment area PM-10 SIP for Lamar, Colorado.

DATES: Comments on this proposed action must be received in writing by 
May 6, 1994.

ADDRESSES: Written comments should be addressed to: Vicki Stamper, 
8ART-AP, Environmental Protection Agency, Region VIII, 999 18th Street, 
suite 500, Denver, Colorado 80202-2466.
    Copies of the State's submittal and other information are available 
for inspection during normal business hours at the following locations:

Air Programs Branch, Environmental Protection Agency, Region VIII, 999 
18th Street, suite 500, Denver, Colorado 80202-2405.
Air Pollution Control Division, Colorado Department of Health, 4300 
Cherry Creek Drive South, Denver, Colorado 80222-1530.

FOR FURTHER INFORMATION CONTACT: Vicki Stamper, 8ART-AP, Environmental 
Protection Agency, Region VIII, 999 18th Street, suite 500, Denver, 
Colorado 80202-2466, (303) 293-1765.

SUPPLEMENTARY INFORMATION:

I. Background

    Lamar, Colorado was designated nonattainment for PM-10 and 
classified as moderate under sections 107(d)(4)(B) and 188(a) of the 
Clean Air Act (Act) upon enactment of the Clean Air Act Amendments of 
1990.\1\ (See 56 FR 56694, November 6, 1991 and 40 CFR 81.306.) The air 
quality planning requirements for moderate PM-10 nonattainment areas 
are set out in subparts 1 and 4 of part D of title I of the Act. The 
EPA has issued a ``General Preamble'' describing EPA's preliminary 
views on how EPA intends to review SIPs and SIP revisions submitted 
under title I of the Act, including those State submittals containing 
moderate PM-10 nonattainment area SIP requirements (see generally 57 FR 
13498 (April 16, 1992) and 57 FR 18070 (April 28, 1992)). Because EPA 
is describing its interpretations here only in broad terms, the reader 
should refer to the General Preamble for a more detailed discussion of 
the interpretations of title I advanced in this proposal and the 
supporting rationale. In this rulemaking action on the Colorado 
moderate PM-10 SIP for the Lamar PM-10 nonattainment area, EPA is 
proposing to apply its interpretations taking into consideration the 
specific factual issues presented. Thus, EPA will consider any timely 
submitted comments before taking final action on this proposal.
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    \1\The 1990 Amendments to the Clean Air Act made significant 
changes to the Act. See Pub. L. No. 101-549, 104 Stat. 2399. 
References herein are to the Clean Air Act, as amended (``the 
Act''). The Clean Air Act is codified, as amended, in the U.S. Code 
at 42 U.S.C. 7401, et seq.
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    Those states containing initial moderate PM-10 nonattainment areas 
were required to submit, among other things, the following provisions 
by November 15, 1991:
    1. Provisions to assure that reasonably available control measures 
(RACM) (including such reductions in emissions from existing sources in 
the area as may be obtained through the adoption, at a minimum, of 
reasonably available control technology--RACT) shall be implemented no 
later than December 10, 1993;
    2. Either a demonstration (including air quality modeling) that the 
plan will provide for attainment as expeditiously as practicable but no 
later than December 31, 1994 or a demonstration that attainment by that 
date is impracticable;
    3. Quantitative milestones which are to be achieved every 3 years 
and which demonstrate reasonable further progress (RFP) toward 
attainment by December 31, 1994; and
    4. Provisions to assure that the control requirements applicable to 
major stationary sources of PM-10 also apply to major stationary 
sources of PM-10 precursors except where the Administrator determines 
that such sources do not contribute significantly to PM-10 levels which 
exceed the NAAQS in the area. See sections 172(c), 188, and 189 of the 
Act.
    Some provisions are due at a later date. States with initial 
moderate PM-10 nonattainment areas were required to submit a permit 
program for the construction and operation of new and modified major 
stationary sources of PM-10 by June 30, 1992 (see section 189(a)). Such 
States also must submit contingency measures by November 15, 1993 which 
become effective without further action by the State or EPA, upon a 
determination by EPA that the area has failed to achieve RFP or to 
attain the PM-10 NAAQS by the applicable statutory deadline. See 
section 172(c)(9) and 57 FR 13510-13512, 13543-13544.

II. This Action

    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittals (see 57 FR 13565-13566). In this action, EPA 
is proposing to grant approval of the Lamar plan revision which was due 
to EPA on November 15, 1991 and submitted by the State on May 27, 1993. 
EPA believes the attainment plan for Lamar meets all of the applicable 
requirements of the Act.
    Since the Lamar PM-10 SIP was not submitted by November 15, 1991 as 
required by section 189(a)(2)(A) of the Act, EPA made a finding 
pursuant to section 179 of the Act that the State failed to submit the 
SIP and notified the Governor in a letter dated December 16, 1991. See 
57 FR 19906 (May 8, 1992). After the Lamar PM-10 SIP was submitted on 
May 27, 1993, EPA found the submittal to be complete pursuant to 
section 110(k)(1) of the Act and notified the Governor accordingly in a 
letter dated June 14, 1993. This completeness determination corrected 
the State's deficiency and, therefore, terminated the 18-month 
sanctions clock under section 179 of the Act.

A. Analysis of State Submission

1. Procedural Background
    The Act requires States to observe certain procedural requirements 
in developing implementation plans and plan revisions for submission to 
EPA. Section 110(a)(2) of the Act provides that each implementation 
plan submitted by a State must be adopted after reasonable notice and 
public hearing.\2\ Section 110(l) of the Act similarly provides that 
each revision to an implementation plan submitted by a State under the 
Act must be adopted by such State after reasonable notice and public 
hearing.
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    \2\Also Section 172(c)(7) of the Act requires that plan 
provisions for nonattainment areas meet the applicable provisions of 
section 100(a)(2).
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    The EPA also must determine whether a submittal is complete and 
therefore warrants further EPA review and action (see section 110(k)(1) 
and 57 FR 13565). The EPA's completeness criteria for SIP submittals 
are set out at 40 CFR part 51, appendix V (1992). The EPA attempts to 
make completeness determinations within 60 days of receiving a 
submission. However, a submittal is deemed complete by operation of law 
if a completeness determination is not made by EPA 6 months after 
receipt of the submission.
    After providing more than 30 days of prior public notice, the State 
of Colorado held a public hearing on April 15, 1993 to entertain public 
comment on the implementation plan for Lamar. The plan for Lamar was 
subsequently adopted by the State and submitted by the Governor by 
letter dated May 27, 1993 as a proposed revision to the SIP. EPA 
received the submittal on June 3, 1993.
    The SIP revision was reviewed by EPA to determine completeness 
shortly after its submittal, in accordance with the completeness 
criteria set out at 40 CFR part 51, appendix V. The submittal was found 
to be complete, and a letter dated June 14, 1993 was forwarded to the 
Governor indicating the completeness of the submittal and the next 
steps to be taken in the review process. In this action, EPA proposes 
to approve the State of Colorado's PM-10 SIP submittal for Lamar 
relative to those moderate area PM-10 SIP requirements due on November 
15, 1991 and invites public comment on the action.
2. Accurate Emissions Inventory
    Section 172(c)(3) of the Act requires that nonattainment plan 
provisions include a comprehensive, accurate, current inventory of 
actual emissions from all sources of relevant pollutants in the 
nonattainment area. The emissions inventory should also include a 
comprehensive, accurate, and current inventory of allowable emissions 
in the area. Because the submission of such inventories is a necessary 
adjunct to an area's attainment demonstration (or demonstration that 
the area cannot practicably attain), the emissions inventories must be 
received with the submission (see 57 FR 13539).
    The State of Colorado submitted a winter/spring season emissions 
inventory for the base year of 1992. A winter/spring season emissions 
inventory was calculated because the highest PM- 10 concentrations 
generally occur in the winter/spring season in Lamar. The base year 
inventory identified area sources as the primary cause of high PM-10 
concentrations, which contributed 99 percent of the total emissions, 
with wind erosion from agriculture lands contributing 49 percent, re-
entrained road dust from paved and unpaved roads contributing 24 
percent, cattle feedlots contributing 15 percent, residential wood 
burning contributing 8 percent, and point sources contributing 1 
percent. The remaining 3 percent of PM-10 emissions was due to 
emissions from tailpipes, agricultural tilling, and storage piles. The 
emission inventory demonstrates that wind erosion from agricultural 
land is the principal contributor to PM-10 emissions in the Lamar 
nonattainment area. However, the State and EPA believe that during the 
conditions when the PM-10 exceedances have been known to occur (high 
wind days preceded by warm, dry weather), PM-10 from wind erosion may 
be coming into the area from land much farther away than the area 
modeled by the State in developing the Lamar PM-10 emissions inventory. 
Thus, on the high wind days, agricultural emissions not in the 
immediate area surrounding Lamar may represent a much greater 
contribution to total PM-10 emissions in the area. However, emissions 
from such sources not in the immediate area surrounding Lamar were 
difficult to estimate.
    The EPA is proposing to approve the emissions inventory because it 
generally appears to be accurate and comprehensive, and provides a 
sufficient basis for determining the adequacy of the attainment 
demonstration for this area consistent with the requirements of 
sections 172(c)(3) and 110(a)(2)(K) of the Act.\3\ For further details 
see the Technical Support Document (TSD).
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    \3\The EPA issued guidance on PM-10 emissions inventories prior 
to the enactment of the Clean Air Act Amendments in the form of the 
1987 PM-10 SIP Development Guideline. The guidance provided in this 
document appears to be consistent with the revised Act.
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3. RACM (Including RACT)
    As noted, the initial moderate PM-10 nonattainment areas must 
submit provisions to assure that RACM (including RACT) are implemented 
no later than December 10, 1993 (see sections 172(c)(1) and 
189(a)(1)(C) of the Act). The General Preamble contains a detailed 
discussion of EPA's interpretation of the RACM (including RACT) 
requirement (see 57 FR 13539-13545 and 13560-13561). In Lamar, wind 
erosion from agricultural farmland in the area was identified as the 
principal contributor to the PM-10 nonattainment problem, and these 
emissions will be controlled through reliance on the soil conservation 
measures of the Food Security Act (FSA). See e.g., 16 U.S.C. 3801, 
3811-3813.
    The FSA, which was enacted in 1985, applies to any farmer 
participating in a federal farm subsidies program. One of the main 
provisions of the FSA requires farmers who cultivate highly erodible 
land (which includes the majority of the farmland surrounding Lamar) to 
develop and implement soil conservation plans. The conservation plan is 
to document the decisions of an affected farmer with respect to 
location, land use, tillage systems, and conservation treatment 
measures and schedules. The plan is to be based on the local Soil 
Conservation Service technical guide, and it is to be approved by the 
local soil conservation district. See 16 U.S.C. 3812(a)(2). The law 
provides that if such a conservation plan is actively applied by 
January 1, 1990 or 2 years after the Soil Conservation Service has 
completed a soil survey for the farm, whichever is later, affected 
farmers shall have until January 1, 1995 to comply with the plan 
without being subject to ineligibility for certain program loans, 
payments, and benefits.
    In the area surrounding Lamar, approximately 75-80 percent of the 
agricultural lands are subject to the soil conservation requirements. 
According to the Southeast Regional Soil Conservation Service (SCS) 
office, all of the farmers subject to the FSA in the Lamar area have 
developed conservation plans, and most of the farmers in the Lamar area 
have already begun at least partial implementation of these plans.\4\ 
The local SCS office has estimated that the implementation of these 
plans will result in a 70 percent reduction in wind erosion emissions 
from the non-irrigated farmland surrounding Lamar (which represents 85 
percent of the farmland subject to the FSA in the Lamar area).
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    \4\Per December 4, 1992 telephone coversation between Vicki 
Stamper, U.S. EPA Region VIII, and Lorenz Sutherland, Southeast 
Colorado Regional SCS office.
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     While the State is relying on these provisions to reduce the PM-10 
emissions from wind erosion in the Lamar area, the State did not adopt 
these measures into the SIP or take credit for these control measures. 
Since these measures are federally mandated and will be implemented by 
the U.S. Department of Agriculture, it is not necessary for the State 
to adopt these measures into the SIP. No credit was taken for these 
measures because of the difficulty in estimating the effectiveness of 
these measures and, moreover, because no credit was needed to 
demonstrate attainment or maintenance of the PM-10 NAAQS in Lamar (see 
section II.A.4. of this document). Nevertheless, EPA does believe that 
the provisions of the FSA will have a significant impact on the 
emissions from wind erosion from agricultural land in the Lamar area.
    RACT does not require controls on stationary sources in the Lamar 
nonattainment area because the point source emissions in the Lamar area 
are de minimis, and control of such sources would not expedite 
attainment and maintenance of the PM-10 NAAQS. See 57 FR 13540, 13543.
    There are also Statewide control measures that apply in the Lamar 
area. Colorado Regulation No. 4 requires new wood stoves to meet the 
emission requirements of EPA's Standards of Performance for New 
Residential Wood Heaters in 40 CFR 60.532(b). Colorado Regulation No. 3 
regulates the construction and modification of new stationary sources 
of PM-10.\5\ These measures will help to reduce emissions from new 
stationary source growth and residential wood combustion.
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    \5\The State is required by the amended Clean Air Act to adopt a 
revised new source review permit program for the construction and 
operation of new and modified stationary sources. See Section 
189(a)(1)(A). This SIP revision, which was submitted by the State on 
January 15, 1993, was due independent of the November 15, 1991 
moderate PM-10 nonattainment area SIP requirements addressed in this 
action and will be addressed in a separate notice. See section 
189(a)(2)(A) of the Act.
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    A more detailed discussion of the individual source contributions, 
the associated control measures, and an explanation as to why certain 
available control measures were not adopted, can be found in the TSD. 
EPA has reviewed the State's explanation and associated documentation 
and concluded that it adequately justifies the control measures to be 
implemented. The Lamar PM-10 SIP demonstrates that the area will attain 
the PM-10 NAAQS by December 31, 1994. By this notice, EPA is proposing 
to approve Colorado's SIP submittal for Lamar as meeting the RACM 
(including RACT) requirement. However, EPA is not proposing action on 
Regulations No. 3 and 4 because EPA has previously approved these 
regulations in separate actions (see the TSD for further information).
4. Demonstration
    As noted, the initial moderate PM-10 nonattainment areas must 
submit a demonstration (including air quality modeling) showing that 
the plan will provide for attainment as expeditiously as practicable 
but no later than December 31, 1994 (see section 189(a)(1)(B) of the 
Act). Alternatively, the State must show that attainment by December 
31, 1994 is impracticable.
    EPA regulations provide that the adequacy of a control strategy to 
provide for timely attainment must be demonstrated by means of a 
proportional model or dispersion model or other procedure which is 
shown to be adequate and appropriate (see 40 CFR 51.112(a)). EPA policy 
specifies that the preferred approach for estimating the air quality 
impacts of emissions of PM-10 is to use receptor modeling in 
combination with dispersion modeling. However, on July 5, 1990, EPA 
issued guidance providing that, in certain situations, it may be more 
appropriate to rely on a receptor model demonstration alone as the 
basis for the attainment demonstration (see July 5, 1990 memo to 
Regional Air Branch Chiefs from Robert D. Bauman, Chief of SO2/
Particulate Matter Programs Branch and Joseph Tikvart, Chief of Source 
Receptor Analysis Branch). Lamar met the criteria discussed in the July 
5, 1990 memo to justify using receptor modeling alone and had 
originally planned to use this approach in its attainment 
demonstration. However, after further review, the State determined that 
the chemical mass balance (CMB) analysis (i.e., analysis of source 
contributions from PM-10 monitoring filters) to be used in the receptor 
model was inadequate and decided to base the attainment and maintenance 
demonstration on simple emissions rollback modeling, which involves 
using the ratio of the design day ambient concentration of 101 
g/m\3\ to the design day emissions and projecting future 
concentrations.
    Because the Lamar attainment and maintenance demonstrations did not 
follow EPA general guidance, the State included a commitment in the 
Lamar PM-10 SIP to conduct revised CMB analyses on all filters greater 
than 100 g/m\3\ and to use this information to assess the 
adequacy of the SIP. On September 20, 1993, the State submitted the 
revised CMB analysis but did not utilize the results in calculating a 
revised attainment and maintenance demonstration. The State determined 
that the receptor modeling performed for Lamar did not provide the 
conclusive source contribution information that would be necessary in 
order to adequately revise the Lamar PM-10 attainment and maintenance 
demonstrations. EPA has reviewed the State's analysis and concurs with 
the State's justification for using emissions rollback modeling in its 
attainment demonstration. In addition, because the emissions rollback 
modeling demonstration accounted for growth in source categories that 
were not even identified in the CMB analysis, EPA believes that the use 
of emissions rollback modeling provides for a more conservative 
prediction of future concentrations. Thus, EPA believes that the 
State's attainment demonstration adequately demonstrates that the Lamar 
PM-10 nonattainment area will remain in attainment and maintain the 24-
hour PM-10 NAAQS. (See the TSD for further information.)
    The 24-hour PM-10 NAAQS is 150 g/m\3\, and the standard is 
attained when the expected number of days per calendar year with a 24-
hour average concentration above 150 g/m\3\ is equal to or 
less than one (see 40 CFR 50.6). The annual PM-10 NAAQS is 50 
g/m\3\, and the standard is attained when the expected annual 
arithmetic mean concentration is less than or equal to 50 g/
m\3\ (id.). The demonstration predicted that the 24-hour design 
concentration in the attainment year of 1994 will be 115 g/
m\3\, thus demonstrating attainment of the 24-hour PM-10 NAAQS. The 
demonstration also showed that the PM-10 NAAQS will be maintained in 
future years by predicting a 24-hour design concentration in 1997 of 
116 g/m\3\.
    Since no violations of the annual PM-10 NAAQS have been monitored 
in the Lamar area and since the attainment demonstration in the Lamar 
PM-10 SIP clearly shows attainment and maintenance of the 24-hour PM-10 
NAAQS, it is reasonable and adequate to assume that protection of the 
24-hour standard will be sufficient to protect the annual standard as 
well. For a more detailed description of the attainment demonstration, 
see the TSD accompanying this document.
5. PM-10 Precursors
    The control requirements which are applicable to major stationary 
sources of PM-10 also apply to major stationary sources of PM-10 
precursors, unless EPA determines such sources do not contribute 
significantly to PM-10 levels in excess of the NAAQS in that area (see 
section 189(e) of the Act).
    The analysis of the air quality and emissions data for the Lamar 
nonattainment area indicates that the PM-10 exceedances in the Lamar 
area are generally attributable to particulate matter emissions from 
area sources, mainly windblown emissions from agricultural lands, re-
entrained road dust, cattle feed lots, and residential wood combustion. 
In addition, the emissions inventory for this area did not reveal any 
major stationary sources of PM-10 precursors. Consequently, EPA is 
proposing to find that major stationary sources of precursors of PM-10 
do not contribute significantly to PM-10 levels in excess of the NAAQS. 
If finalized, this finding would exclude major stationary sources of 
PM-10 precursors from the applicability of PM-10 nonattainment area 
control requirements. Further discussion of the analyses and supporting 
rationale for EPA's proposed finding are contained in the TSD 
accompanying this document. Note that while EPA is making a general 
finding for this area, this finding is based on the current character 
of the area including, for example, the existing mix of sources in the 
area. It is possible, therefore, that future growth could change the 
significance of precursors in the area. The EPA intends to issue future 
guidance addressing such potential changes in the significance of 
precursor emissions in an area.
6. Quantitative Milestones and Reasonable Further Progress
    The PM-10 nonattainment area plan revisions demonstrating 
attainment must contain quantitative milestones which are to be 
achieved every 3 years until the area is redesignated attainment and 
which demonstrate RFP, as defined in section 171(1), toward attainment 
by December 31, 1994 (see section 189(c) of the Act). RFP is defined in 
section 171(1) as such annual incremental reductions in emissions of 
the relevant air pollutant as are required by part D or may reasonably 
be required by the Administrator for the purpose of ensuring attainment 
of the applicable NAAQS by the applicable date.
    In implementing the quantitative milestone and RFP provisions for 
this initial moderate area, EPA has reviewed the attainment 
demonstration for the area to determine the nature of any milestones 
necessary to ensure timely attainment and whether annual incremental 
reductions should be required in order to ensure attainment of the PM-
10 NAAQS by December 31, 1994 (see section 171(1)). Because the Lamar 
area can demonstrate expeditious attainment of the PM-10 NAAQS without 
taking credit for the reliance on the soil conservation plans, no 
further reductions are necessary. Therefore, EPA believes the Lamar PM-
10 SIP satisfies the quantitative milestone and RFP requirement. 
However, there will be emissions reductions that occur as a result of 
the federally mandated soil conservation plans, which will help to 
ensure that the area attains and maintains the PM-10 NAAQS.
7. Enforceability Issues
    All measures and other elements in the SIP must be enforceable by 
the State and EPA (see sections 172(c)(6), 110(a)(2)(A) of the Act and 
57 FR 13556). The EPA criteria addressing the enforceability of SIPs 
and SIP revisions were stated in a September 23, 1987 memorandum (with 
attachments) from J. Craig Potter, Assistant Administrator for Air and 
Radiation, et al. (see 57 FR 13541). Nonattainment area plan provisions 
must also contain a program that provides for enforcement of the 
control measures and other elements in the SIP (see section 
110(a)(2)(C)).
    The specific control measures contained in the SIP are addressed 
above under section 3 entitled ``RACM (including RACT).'' The State, 
while relying on the soil conservation measures of the FSA, has not 
adopted these measures into the SIP or taken any credit for these 
measures. Since these measures are federally mandated and will be 
implemented by the U.S. Department of Agriculture, they are considered 
to be federally enforceable. Thus, it is not necessary for the State to 
adopt these measures into the SIP.
    As discussed in section 3 above, there are State-wide regulations 
that will also impact the emissions of PM-10 in the Lamar nonattainment 
area. These regulations include Colorado Regulation No. 4, which 
requires all wood stoves sold after July 1, 1991 to meet the emission 
requirements of EPA's Standards of Performance for New Residential Wood 
Heaters in 40 CFR 60.532(b), and Colorado Regulation No. 3, which 
requires construction permits for new or modified stationary sources. 
EPA previously reviewed Colorado Regulations No. 3 and 4 at the time 
these regulations were approved by EPA as part of the SIP, and it was 
determined that these regulations met the enforceability criteria of 
the September 23, 1987 Potter Memorandum (see the TSD for information 
on EPA approvals of these regulations).\6\
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    \6\Note that the current version of Colorado Regulation No. 3 
approved by EPA does not meet all of the applicable requirements of 
the amended Act. As discussed in footnote number 4, the State 
submitted revisions to Regulation No. 3 in January of 1993 which are 
being evaluated by EPA. EPA will act on that submittal in a separate 
notice.
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    The State of Colorado has a program that will ensure that the 
measures contained in the SIP are adequately enforced. The Colorado Air 
Pollution Control Division (APCD) has the authority to implement and 
enforce all emission limitations and control measures adopted by the 
State, including the requirements of any emission control regulations, 
the SIP, and any permit. The APCD has the authority to impose civil 
penalties of up to $15,000 per day per violation, as well as criminal 
penalties. Thus, EPA believes the State has adequate enforcement 
capabilities to ensure compliance with the Lamar PM-10 SIP and the 
State-wide regulations. The TSD contains further information on the 
State-wide regulations, enforceability requirements, and a discussion 
of the personnel and funding intended to support effective 
implementation of the control measures.
8. Contingency Measures.
    As provided in section 172(c)(9) of the Act, all moderate 
nonattainment area SIPs that demonstrate attainment must include 
contingency measures. See generally 57 FR 13510-13512 and 13543-13544. 
These measures were to be submitted by November 15, 1993 for the 
initial moderate nonattainment areas. Thus, the measures were due 
separate from the requirements addressed in this notice. Contingency 
measures should consist of other available measures that are not part 
of the area's control strategy. These measures must take effect without 
further action by the State or EPA, upon a determination by EPA that 
the area has failed to make RFP or attain the PM-10 NAAQS by the 
applicable statutory deadline. The Lamar SIP submittal addressed in 
this notice did not include any contingency measures. The State 
submitted the contingency measures for Lamar as a revision to the SIP 
on December 9, 1993. EPA will act on the December 1993 submittal in a 
separate notice.

III. Implications of This Action

    The EPA is proposing to approve the plan revision submitted by 
Colorado for the Lamar nonattainment area on May 27, 1993 to satisfy 
those moderate area PM-10 SIP requirements due on November 15, 1991. 
Among other things, the State of Colorado has adequately demonstrated 
that the Lamar moderate PM-10 nonattainment area will attain the PM-10 
NAAQS by December 31, 1994.
    As noted, additional submittals for the initial moderate PM-10 
nonattainment areas are due at later dates. The EPA will determine the 
adequacy of any such submittal as appropriate.

IV. Request for Public Comments

    The EPA is requesting comments on all aspects of this proposal. As 
indicated at the outset of this document, EPA will consider any 
comments received by May 6, 1994.

V. Executive Order (EO) 12866

    This action has been classified as a Table 2 action by the Regional 
Administrator under the procedures published in the Federal Register on 
January 19, 1989 (54 FR 2214-2225), as revised by an October 4, 1993 
memorandum from Michael H. Shapiro, Acting Assistant Administrator for 
Air and Radiation. A future notice will inform the general public of 
these tables. On January 6, 1989, the Office of Management and Budget 
(OMB) waived Table 2 and 3 SIP revisions (54 FR 2222) from the 
requirements of section 3 of Executive Order 12291 for a period of two 
years. The U.S. EPA has submitted a request for a permanent waiver for 
Table 2 and 3 SIP revisions. The OMB has agreed to continue the 
temporary waiver until such time as it rules on EPA's request. This 
request continues in effect under Executive Order 12866 which 
superseded Executive Order 12291 on September 30, 1993.

VI. Regulatory Flexibility

    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 economic 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 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, I certify that it does 
not have a significant impact on small entities affected. Moreover, due 
to the nature of the federal-state relationship under the Act, 
preparation of a regulatory flexibility analysis would constitute 
federal inquiry into the economic reasonableness of state action. The 
Act forbids EPA to base its actions concerning SIPs on such grounds. 
Union Electric Co. v. U.S. E.P.A., 427 U.S. 246, 256-66 (S.Ct. 1976); 
42 U.S.C. section 7410(a)(2).
    Nothing in this action should be construed as permitting or 
allowing or establishing a precedent for any future request for 
revision to any SIP. Each request for revision to the SIP shall be 
considered separately in light of specific technical, economic, and 
environmental factors and in relation to relevant statutory and 
regulatory requirements.

List of Subjects

40 CFR Part 52

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

40 CFR Part 81

    Air pollution control, National parks, Wilderness areas.

    Authority: 42 U.S.C. 7401-7671q.

    Dated: March 18, 1994.
William P. Yellowtail,
Regional Administrator.
[FR Doc. 94-8228 Filed 4-5-94; 8:45 am]
BILLING CODE 6560-50-P