[Federal Register Volume 62, Number 250 (Wednesday, December 31, 1997)]
[Rules and Regulations]
[Pages 68188-68196]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-33958]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 52 and 81

[CO-001-0006a & CO-001-0021a; FRL-5934-2]


Clean Air Act Approval and Promulgation of PM10 
Implementation Plan for Colorado; Designation of Areas for Air Quality 
Planning Purposes; Steamboat Springs

AGENCY: Environmental Protection Agency (EPA).

ACTION: Direct final rule.

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SUMMARY: EPA approves the State implementation plan (SIP) submitted by 
the State of Colorado to achieve attainment and maintenance of the 
National Ambient Air Quality Standards (NAAQS) for particulate matter 
with an aerodynamic diameter less than or equal to a nominal 10 
micrometers (PM10), including among other things, control 
measures, technical analyses, quantitative milestones and contingency 
measures. The SIP was submitted by the Governor of Colorado with a 
letter dated September 16, 1997 to satisfy certain Federal requirements 
for an approvable SIP for the Steamboat Springs, Colorado moderate 
PM10 nonattainment area, as designated effective January 20, 
1994. In addition, EPA approves the Steamboat Springs emergency episode 
plan. EPA also amends the boundary for the Steamboat Springs 
nonattainment area to clarify the original description.

DATES: This action is effective on March 2, 1998 unless adverse 
comments are received by January 30, 1998. If the effective date is 
delayed, timely notice will be published in the Federal Register.

ADDRESSES: Comments should be addressed to: Richard R. Long, Director, 
Air Program, EPA Region VIII at the address listed below. Copies of the 
State's submittal and other information are available for inspection 
during normal business hours at the following locations: Air Program, 
Environmental Protection Agency, Region VIII, 999 18th Street, suite 
500, Denver, Colorado 80202-2405; and Colorado Department of Public 
Health and Environment, Air Pollution Control Division, 4300 Cherry 
Creek Drive South, Denver, Colorado 80222-1530.

FOR FURTHER INFORMATION CONTACT: Amy Platt, 8P2-A, Environmental 
Protection Agency, Region VIII, 999 18th Street, suite 500, Denver, 
Colorado 80202-2466, (303) 312-6449.

SUPPLEMENTARY INFORMATION:

I. Background

    The Steamboat Springs, Colorado area was designated nonattainment 
for PM10 and classified as moderate under section 107(d)(3) 
of the Clean Air Act, on December 21, 1993. 1 See 57 FR 
43846 (September 22, 1992), 58 FR 67334 (December 21, 1993) and 40 CFR 
81.306 (Routt County (part)). The Steamboat Springs designation became 
effective on January 20, 1994. The air quality planning requirements 
for moderate PM10 nonattainment areas 2 are set 
out in Subparts 1 and 4 of Title I of the Act.3
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    \1\ The 1990 Amendments to the Clean Air Act made significant 
changes to the Act. See Pub. L. 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.
    \2\ The requirements which are the subject of this document 
arise under the pre-existing PM NAAQS. EPA promulgated a new PM 
NAAQS on July 18, 1997, which became effective on September 16, 
1997.
    \3\ Subpart 1 contains provisions applicable to nonattainment 
areas generally and Subpart 4 contains provisions specifically 
applicable to PM10 nonattainment areas. At times, Subpart 
1 and Subpart 4 overlap or conflict. EPA has attempted to clarify 
the relationship among these provisions in the ``General Preamble'' 
and, as appropriate, in today's notice and supporting information.
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    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 PM10 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 
document and the supporting rationale. In this document and supporting 
rationale, EPA is applying its interpretations considering the specific 
factual issues presented.
    A State containing a moderate PM10 nonattainment area 
designated after the 1990 Amendments is required to submit, among other 
things, the following provisions within 18 months of the effective date 
of the designation (i.e., these provisions were due for the Steamboat 
Springs area by July 20, 1995):
    1. Provisions to assure that reasonably available control measures 
(RACM) (including such reductions in emissions

[[Page 68189]]

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 four years after designation 
(i.e., January 20, 1998 for Steamboat Springs);
    2. Either a demonstration (including air quality modelling) that 
the plan will provide for attainment as expeditiously as practicable 
but no later than the end of the sixth calendar year after the 
effective date of designation (i.e., December 31, 1999 for Steamboat 
Springs), or a demonstration that attainment by that date is 
impracticable;
    3. Quantitative milestones which demonstrate reasonable further 
progress (RFP) toward the attainment date (i.e., December 31, 1999 for 
Steamboat Springs). Since the SIP for a new nonattainment area is due 
18 months after the area is designated as nonattainment, the first 3-
year milestone is to be achieved 4 \1/2\ years after nonattainment 
designation (i.e., July 20, 1998 for Steamboat Springs) and the second 
milestone must be achieved three years after the first milestone or 7 
\1/2\ years after nonattainment designation (i.e., July 20, 2001 for 
Steamboat Springs);
    4. Provisions to assure that the control requirements applicable to 
major stationary sources of PM10 also apply to major 
stationary sources of PM10 precursors except where the 
Administrator determines that such sources do not contribute 
significantly to PM10 levels which exceed the NAAQS in the 
area. See sections 172(c), 188, and 189 of the Act; and
    5. Contingency measures which 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 EPA's 
determination that the area has failed to make RFP or attain the 
PM10 NAAQS by the applicable deadline. See section 172(c)(9) 
of the Act.

II. This Action

    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittals (see 57 FR 13565-13566). The Governor of 
Colorado submitted the Steamboat Springs PM10 SIP with a 
letter dated September 16, 1997. The Steamboat Springs moderate 
nonattainment area plan includes, among other things, technical 
analyses, control measures to satisfy the RACM requirement, a 
demonstration (including air quality modelling) that attainment and 
maintenance of the PM10 NAAQS will be achieved by the 
required dates, and enforceability documentation. In this final 
rulemaking, EPA announces its approval of those elements of the 
Steamboat Springs PM10 SIP which were due on July 20, 1995 
and submitted on September 16, 1997.
    In addition, EPA has determined that major sources of precursors of 
PM10 do not contribute significantly to PM10 
levels in excess of the NAAQS in Steamboat Springs.4
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    \4\ The consequences of this finding are to exclude these 
sources from the applicability of PM10 nonattainment area 
control requirements. Note that EPA's 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.
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    Finally, EPA is amending the nonattainment area boundary 
description for Steamboat Springs in order to clarify the original 
description.

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. 5 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.
    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). EPA's completeness criteria for SIP submittals are 
set out at 40 CFR part 51, appendix V. 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 six months after receipt 
of the submission.
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    \5\ Also Section 172(c)(7) of the Act requires that plan 
provisions for nonattainment areas meet the applicable provisions of 
Section 110(a)(2).
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    To entertain public comment on the PM10 implementation 
plan for Steamboat Springs, the Steamboat Springs City Council and the 
Routt County Commission held public hearings on June 6, 1995 and June 
12, 1995, respectively. The State of Colorado, after providing adequate 
public notice, held a public hearing on September 21, 1995. After 
considering all public comments and following the public hearing, the 
Steamboat Springs PM10 SIP was adopted by the Colorado Air 
Quality Control Commission (AQCC). The Steamboat Springs 
PM10 SIP was submitted by the Governor in a letter dated 
August 7, 1996. The Steamboat Springs PM10 SIP was reviewed 
by EPA to determine completeness 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 August 29, 1996 was forwarded to the 
Governor indicating the completeness of the submittal and the next 
steps in the review process.
    Subsequently, the Steamboat Springs City Council and the Routt 
County Commission held public hearings on extensive revisions to the 
Steamboat Springs PM10 SIP on September 17, 1996 and 
approved the revisions. The Colorado AQCC conducted a public hearing on 
the revised SIP on October 17, 1996 and adopted the revisions. In a 
January 31, 1997 letter from Margie Perkins, Air Pollution Control 
Division (APCD), to Richard Long, EPA, the State requested that EPA 
Region VIII delay processing of the original Steamboat Springs SIP 
submitted with the August 7, 1996 Governor's letter. The reason 
provided for the request was that the substantial revisions adopted on 
October 17, 1996 made the original SIP and regulations obsolete. These 
revisions were submitted by the Governor with a letter dated September 
16, 1997, and the State requested that this documentation completely 
replace the August 7, 1996 submittal.
    The September 16, 1997 Steamboat Springs PM10 SIP 
submittal was reviewed by EPA to determine completeness in accordance 
with the completeness criteria set out at 40 CFR part 51, appendix V. 
The submittal was found to be complete and an October 20, 1997 letter 
was forwarded to the Governor indicating the completeness of the 
submittal and the next steps in the review process.
    As requested by the State, this rulemaking action is specific to 
the September 16, 1997 submittal.
2. Accurate Emission 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 emission inventory also should include a 
comprehensive, accurate, and current inventory of allowable emissions 
in the area. See, for example, section 110(a)(2)(K). 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 emission

[[Page 68190]]

inventories must be received with the submission (see 57 FR 13539).
    The Colorado APCD chose 1991 as the Steamboat Springs base year 
emissions inventory of PM10 emissions. The results indicate 
that area sources contribute approximately 99% of the total emissions 
for the area, of which re-entrained road dust (including paved and 
unpaved roads) contributes approximately 94% and woodburning 
contributes approximately 5%. Stationary sources accounted for less 
than 1% of the emission inventory. 6
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    \6\ Although emissions from the Craig and Hayden power stations 
were not included in the inventory because these sources are outside 
the inventory domain, the emissions were included in the modelling 
analyses for the SIP to determine impacts on the nonattainment area.
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    EPA is approving the emission inventory because it is 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. 
7 For further details see the Steamboat Springs 
PM10 SIP Technical Support Document (TSD) for this action.
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    \7\ 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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    The September 16, 1997 submittal also establishes an emission 
budget for the Steamboat Springs nonattainment area, which is to be 
used for Federal conformity purposes. The PM10 mobile source 
emission budget for 1999 is 16,661 pounds/day and for 2002 is 20,682 
pounds/day for the modelling domain. These budgets are the 1999 and 
2002 mobile source PM10 emissions presented in Section G. of 
the SIP, which include emissions from vehicle exhaust, brake, and tire 
wear, controlled emissions from paved roads, and unpaved road 
emissions. These budgets are calculated for the emission inventory/
modelling domain, which is somewhat larger than the nonattainment area.
3. RACM (Including RACT)
    As noted, the moderate PM10 nonattainment areas, 
designated after the 1990 Amendments, must submit provisions to assure 
that RACM (including RACT) are implemented no later than January 20, 
1998 (see sections 172(c)(1) and 189(a)(1)(C)). 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 broad terms, the State should identify available control 
measures and evaluate them for their reasonableness in light of the 
feasibility of the controls and the attainment needs of the area. See 
57 FR 13540-13544. A State may reject an available control measure if 
the measure is technologically infeasible or the cost of the control is 
unreasonable. In addition, RACM does not require controls on emissions 
from sources that are insignificant (i.e., de minimis) and does not 
require the implementation of all available control measures where an 
area demonstrates timely attainment and the implementation of 
additional controls would not expedite attainment.
    Colorado's SIP revision for Steamboat Springs contains control 
measures for sources of re-entrained fugitive dust (including paved and 
unpaved roads) and woodburning (including fireplaces and woodstoves). 
In the following table, an outline is presented on these sources, their 
control measures, associated emissions reduction credit, and effective 
dates.

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                                                                                                      Effective 
          Source category                      Control measure             PM10 emissions reduction      date   
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                                    Colorado Air Quality Control          .........................     12/30/96
                                     Commission State Implementation                                            
                                     Plan-Specific Regulations for                                              
                                     Nonattainment Areas, Steamboat                                             
                                     Springs PM10 Nonattainment Area.                                           
Re-entrained fugitive dust........  Sections VIII.B, C. & D. Require      720 kg/day or                         
                                     compliance with specifications for    approximately 1588 lbs/              
                                     street sanding materials, reduction   day fewer PM10 emissions             
                                     in the amount of street sand          than base year.                      
                                     applied, and street sweeping.                                              
Woodburning.......................  Section VIII.E.--Requires continued   Existing local programs               
                                     implementation of local programs to   were given emission                  
                                     restrict the number and type of new   reduction credits in the             
                                     solid fuel burning devices in the     base and attainment year             
                                     nonattainment area.                   emissions inventories.               
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    RACM does not require additional controls on other area sources 
since the plan demonstrates attainment of the NAAQS and implementation 
of additional controls would not further expedite attainment. Further, 
RACT does not require additional controls for the stationary sources in 
the Steamboat Springs nonattainment area because point source emissions 
in the area are de minimis and control of such sources would not 
expedite attainment of the PM10 NAAQS.
    There are also other Statewide control measures that already apply 
in the Steamboat Springs area, which will help curb PM10 
emissions in the Steamboat Springs nonattainment area. Specifically, 
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), and Colorado Regulation No. 3 regulates 
the construction and modification of stationary sources of 
PM10. These measures will help to

[[Page 68191]]

reduce emissions from new stationary source growth and residential wood 
combustion. However, EPA is not acting on Regulation Nos. 3 and 4 at 
this time because EPA has previously approved these regulations. For 
further information, see the TSD accompanying this document.
    A more detailed discussion of the source category contributions, 
associated control measures (including available control technology), 
and an explanation of why certain available control measures were not 
implemented can be found in the TSD. EPA has reviewed the State's 
documentation and concluded that it adequately justifies the control 
measures to be implemented. The implementation of Colorado's 
PM10 nonattainment plan for Steamboat Springs will result in 
the attainment of the PM10 NAAQS by December 31, 1999, and 
maintenance of the PM10 NAAQS through 2002. EPA is approving 
the Steamboat Springs PM10 plan's control strategy as 
satisfying the RACM (including RACT) requirement.
4. Demonstration
    As noted, moderate PM10 nonattainment areas designated 
subsequent to enactment of the 1990 Amendments must submit a 
demonstration (including air quality modelling) showing that the plan 
will provide for attainment as expeditiously as practicable, but no 
later than the end of the sixth calendar year after an area's 
designation to attainment (see section 188(c)(1) of the Act). In the 
case of Steamboat Springs, this attainment deadline is December 31, 
1999, or the State must show that attainment by December 31, 1999, is 
impracticable.
    The attainment demonstration presented in the September 16, 1997 
submittal indicated that the PM10 NAAQS will be attained by 
1999 in the Steamboat Springs area. The 24-hour PM10 NAAQS 
is 150 micrograms/cubic meter (g/m3), and the 
standard is attained when the expected number of days per calendar year 
with a 24-hour average concentration above 150 g/m3 
is equal to or less than one (see 40 CFR 50.6). The annual 
PM10 NAAQS is 50 g/m3, and the standard 
is attained when the expected annual arithmetic mean concentration is 
less than or equal to 50 g/m3 (id.).
    EPA regulations provide that attainment be demonstrated by means of 
a proportional model or dispersion model or other procedure shown to be 
adequate and appropriate for such purposes. See 40 CFR 51.112(a). In 
general, EPA policy provides that the preferred approach for estimating 
the air quality impacts of emissions of PM10 is to use 
receptor modelling in combination with dispersion modelling.
    The State utilized the monitoring and emissions data and control 
measure efficiencies presented in the Steamboat Springs PM10 
SIP as inputs in a dispersion modelling-based attainment demonstration. 
The dispersion model was used to predict concentrations of 
PM10 for the Steamboat Springs nonattainment area. The model 
was first calibrated to accurately predict worst-case PM10 
levels for 1991, for which monitoring data is available. Based upon 
these accurate predictions for 1991, the State is confident that the 
model's predictive capabilities are very good, and also confident that 
the modelling results generated for the attainment year of 1999 are 
reliable.
    The dispersion modelling for Steamboat Springs, submitted with the 
SIP on September 16, 1997, demonstrates attainment of the 24-hour 
PM10 NAAQS by December 31, 1999 since the highest modelled 
concentration for that year is 115 g/m3 at the 
downtown Steamboat Springs receptor. Because no exceedances of the 
PM10 annual NAAQS have been recorded in the Steamboat 
Springs area and because the attainment demonstration submitted with 
the Steamboat Springs SIP shows attainment of the 24-hour 
PM10 NAAQS, EPA believes it is reasonable and adequate to 
assume that protection of the 24-hour standard will be sufficient to 
protect the annual standard as well. The dispersion modelling also 
demonstrates maintenance of the 24-hour PM10 NAAQS by 
December 31, 2002, since the highest modelled concentration for that 
year is 123 g/m3. The control strategies relied on 
to demonstrate timely attainment and maintenance are summarized in the 
section above entitled ``RACM (including RACT).'' For a more detailed 
description of the attainment and maintenance demonstrations and the 
control strategies used, see the TSD accompanying this document.
5. PM10 Precursors
    The control requirements that are applicable to major stationary 
sources of PM10 also apply to major stationary sources of 
PM10 precursors, unless EPA determines such sources do not 
contribute significantly to PM10 levels which exceed the 
NAAQS in that area (see section 189(e) of the Act). The General 
Preamble contains guidance addressing how EPA intends to implement 
section 189(e) (57 FR 13539-13542). An analysis of air quality and 
emissions data for the Steamboat Springs nonattainment area indicates 
that exceedances of the NAAQS are attributable chiefly to direct 
particulate emissions from re-entrained road dust and residential wood 
burning (i.e., area sources). The emissions inventory for Steamboat 
Springs did not reveal any major stationary sources of PM10 
precursors within the inventory domain. The chemical mass balance 
analysis of filters from high concentration days revealed insignificant 
source apportionments to secondaries (approximately 1% to ammonium 
nitrates and approximately 2% to ammonium sulfates). The dispersion 
modelling for the SIP included a screening of major PM10 
stationary sources outside of the nonattainment area, including the 
Hayden and Craig power plants, to determine impacts to the 
nonattainment area. These analyses revealed insignificant source 
apportionments in the nonattainment area to the Hayden and Craig power 
plants, which is logical given the distances that these plants are from 
the nonattainment area. Craig is approximately 37 miles from downtown 
Steamboat Springs and Hayden is approximately 18.5 miles from downtown 
Steamboat Springs.
    Based upon the emissions inventory, chemical mass balance analyses, 
and dispersion modelling, EPA believes that the overall contribution of 
PM10 precursors is insignificant. Therefore, EPA is making 
the determination that major sources of PM10 precursors do 
not contribute significantly to PM10 levels in excess of the 
NAAQS in Steamboat Springs. The consequence of this finding is to 
exclude any such sources from the applicability of PM10 
nonattainment area control requirements. Note that EPA's 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. 
Further discussion of the analyses and supporting rationale for EPA's 
finding are contained in the TSD accompanying this document.
6. New Source Review
    On August 18, 1994 (59 FR 42500-42506), EPA approved the State's 
nonattainment new source review (NSR) permitting regulations for 
sources of PM10 in the State's PM10 nonattainment 
areas. In that notice, EPA stated that, because the Steamboat Springs 
PM10 nonattainment area SIP was not due to be submitted 
until July 20, 1995, EPA would determine the approvability of the 
State's NSR provisions for that nonattainment area when EPA took action 
on the State's SIP submittal for

[[Page 68192]]

Steamboat Springs. Since the State's NSR regulations meet all of the 
Federal requirements for new and modified major stationary sources of 
PM10 locating in moderate PM10 nonattainment 
areas (as discussed in the August 18, 1994 Federal Register), EPA finds 
that the State has met the nonattainment NSR permitting requirements 
for sources of PM10 locating in the Steamboat moderate 
PM10 nonattainment area. In addition, as discussed in 
Section 5. above, EPA finds that major stationary sources of 
PM10 precursors do not contribute significantly to 
PM10 levels in excess of the NAAQS in Steamboat Springs. The 
consequence of this finding is to exclude major stationary sources of 
PM10 precursors in Steamboat Springs from the applicability 
of PM10 nonattainment area control requirements, including 
nonattainment NSR permitting requirements. Thus, the State's 
nonattainment NSR regulations for Steamboat Springs are considered 
fully approvable.
7. Quantitative Milestones and Reasonable Further Progress
    The PM10 nonattainment area plans demonstrating 
attainment must contain quantitative emission reduction milestones 
which are to be achieved every three years until the area is 
redesignated attainment and which demonstrate reasonable further 
progress (RFP), as defined in section 171(1), toward timely attainment. 
While section 189(c) plainly provides that quantitative milestones are 
to be achieved until an area is redesignated attainment, it is silent 
in indicating the starting point for counting the first three-year 
period or how many milestones must be initially addressed. In the 
General Preamble, EPA addressed the statutory gap in the starting point 
for counting the three-year milestones, indicating that it would begin 
from the due date for the applicable implementation plan revision 
containing the control measures for the area (i.e., November 15, 1991 
for initial moderate PM10 nonattainment areas). See 57 FR 
13539. As to the number of milestones, EPA believes that at least two 
milestones must be initially addressed.
    States containing moderate nonattainment areas designated 
subsequent to enactment of the 1990 Amendments are expected to 
initially submit two milestones. States are required to submit SIP's 
for these areas 18 months after their redesignation as nonattainment. 
The attainment date for new PM10 nonattainment areas is ``as 
expeditiously as practicable'' but no later than the end of the sixth 
calendar year after an area's designation as nonattainment. Therefore, 
the attainment date for Steamboat Springs is December 31, 1999.
    Because the SIP revision, including the quantitative milestones 
element, for a new nonattainment area is due 18 months after the area 
is designated as nonattainment, the first 3-year milestone is to be 
achieved 4\1/2\ years after the nonattainment redesignation. Since 
Steamboat Springs redesignation became effective on January 20, 1994, 
the first 3-year milestone must be achieved by July 20, 1998 (i.e., 
1\1/2\ years prior to the attainment deadline). The second quantitative 
milestone must be achieved three years after the first milestone or 
7\1/2\ years after the nonattainment designation. In Steamboat Springs, 
the second quantitative milestone must be achieved by July 20, 2001 
(i.e., 1\1/2\ years after the attainment deadline if the maximum of six 
years is needed to attain the PM10 NAAQS). The second 
quantitative milestone should provide for continued emission reduction 
progress toward attainment and should provide for continued maintenance 
of the NAAQS after the attainment date for the area.8
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    \8\ Section 189(c) provides that quantitative milestones are to 
be achieved ``until the area is redesignated attainment.'' However, 
this endpoint for quantitative milestones is speculative because 
redesignation of an area as attainment is contingent upon several 
factors and future events. Therefore, EPA believes it is reasonable 
for States to initially address the first two milestones. Addressing 
two milestones will ensure that the State continues to maintain the 
NAAQS beyond the attainment date for at least some period during 
which an area could be redesignated attainment. Requiring that 
additional milestones be addressed, at least initially, would place 
a potentially unnecessary planning burden on States containing areas 
that are redesignated attainment. However, in all instances, 
additional milestones must be addressed if an area is not 
redesignated attainment.
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    Because all of the Steamboat Springs emission control measures will 
go into effect in 1996, and because measures have been developed to 
keep the area in attainment through 2002, the State believes, and EPA 
agrees, that the quantitative milestone requirements for emission 
reductions will be achieved.
8. 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) 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 
also must contain a program to provide for enforcement of 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 in Section II.A.3., ``RACM (including RACT).'' The Colorado Air 
Quality Control Commission State Implementation Plan-Specific 
Regulation for Nonattainment Areas, Section VIII. Steamboat Springs 
PM10 Nonattainment Area, became effective on December 30, 
1996. This regulation requires the City of Steamboat Springs to 
continue implementation and enforcement of Ordinance No. 1191 (1991), 
Ordinance No. 1148 (1990), Ordinance No. 1045 (1988), and Ordinance No. 
977 (1987). The State regulation also requires Routt County to continue 
implementation and enforcement of Resolution No. 91-032 (1991). The 
ordinance and resolutions will limit future growth in emissions from 
solid fuel burning devices. The State regulation also includes record 
keeping requirements. The City of Steamboat Springs and Routt County 
must each submit to the APCD by May 31st of each year a report that 
describes the tracking and enforcement of these local control 
strategies. The report must include information on compliance and 
enforcement activities that have occurred during the previous year so 
that the APCD can verify that the ordinances and resolution have been 
properly implemented.
    The Colorado Air Quality Control Commission State Implementation 
Plan-Specific Regulation for Nonattainment Areas, Section VIII., 
Steamboat Springs PM10 Nonattainment Area, also details 
specifications for street sanding materials, requirements for the 
reduction in the amount of street sand applied, and street sweeping 
requirements for Lincoln Avenue. These requirements will limit re-
entrained road dust emissions in the area. To limit woodburning 
emissions in the area, the State regulation also requires continued 
implementation of local programs to restrict the number and type of new 
solid fuel burning devices in the nonattainment area. Annual 
recordkeeping and reporting requirements are detailed for each control 
strategy, as follows.
    Beginning November 1, 1996, each user of street sanding materials 
must submit a report to the APCD which provides a copy of all 
independent tests performed on sanding materials. The report must also 
include the name and address of all suppliers of street sanding 
material along with a description of the location of the supplier's 
aggregate pit

[[Page 68193]]

from which all material was supplied. Files must be maintained for two 
years.
    No later than May 31 of each year, beginning in 1997, the Colorado 
Department of Transportation must submit a report to the APCD which 
demonstrates compliance with the provisions for the reduction of street 
sand applied for the previous sanding season. Files must be maintained 
for two years.
    No later than February 28 and May 31 of each year, beginning in 
1997, the City of Steamboat Springs must submit a report to the APCD 
which demonstrates compliance with the street sweeping requirements for 
Lincoln Avenue. The reports must contain information for the period 
December 1--January 31 and February 1--March 31, respectively, as 
follows: (1) Date of sweeping operation; (2) specific segments of 
Lincoln Avenue swept; (3) type of equipment used; (4) equipment 
malfunctions and downtime, if any; (5) conditions of traffic lanes 
(dry, wet, snow packed, patchy ice, etc.); and (6) general weather 
conditions at time of sweeping operations. Files must be maintained for 
two years.
    No later than May 31 of each year, beginning in 1997, the City of 
Steamboat Springs and Routt County must submit to the APCD a report 
containing information that describes the tracking and enforcement of 
the local woodburning ordinances and resolution. The annual report must 
include information on compliance and enforcement activities that have 
occurred during the previous year.
    EPA has reviewed the Colorado Air Quality Control Commission State 
Implementation Plan-Specific Regulations for Nonattainment Areas, 
Section VIII., Steamboat Springs PM10 Nonattainment Area, 
for enforceability and has determined that it meets all of the criteria 
included in the September 23, 1987 Potter Memorandum.
    As discussed in Section II.A.3. above, there are also State-wide 
regulations that will impact the emissions of PM10 in the 
Steamboat Springs 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 these 
regulations, and determined that they met the enforceability criteria 
of the September 23, 1987 Potter Memorandum and approved them as part 
of the SIP (see the TSD for information on EPA approvals of these 
regulations).
    The State of Colorado has a program that will ensure that the 
measures contained in the SIP are adequately enforced. The Colorado 
APCD has the authority to implement and enforce all emission 
limitations and control measures adopted by the AQCC. In addition, 
Colorado statute provides that the APCD shall enforce against any 
``person'' who violates the emission control regulations of the AQCC, 
the requirements of the SIP, or the requirements of any permit. The 
definition of ``person'' includes any ``municipal corporation, county, 
city and county or other political subdivision of the State,'' such as 
the City of Steamboat Springs and Routt County. Civil penalties of up 
to $15,000 per day per violation are provided for in the State statute 
for any person in violation of these requirements, and criminal 
penalties are also provided for in the State statute.
    Thus, EPA has determined that the control measures contained in the 
SIP revision for Steamboat Springs are enforceable and that the APCD 
has adequate enforcement capabilities to ensure compliance with those 
control measures and the State 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.
9. 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. 
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 EPA's 
determination that the area has failed to make RFP or attain the 
PM10 NAAQS by the applicable statutory deadline.
    The Governor of Colorado submitted PM10 contingency 
measures for the Steamboat Springs area with a September 16, 1997 
letter. These measures, as discussed below, require additional street 
sweeping for Lincoln Avenue and the downtown core area within two 
months following EPA's determination that the Steamboat Springs 
moderate PM10 nonattainment area failed to attain the 
PM10 NAAQS or make reasonable further progress (RFP) in 
reducing emissions.
    The City of Steamboat Springs will expand the sweeping program to 
include the traffic lanes of Lincoln Avenue from 13th Street west for 
one mile, and Lincoln Avenue from Old Fish Creek Falls Road to Pine 
Grove Road. These roadways must be swept within four days of the 
roadways becoming free and clear of snow and ice following each sanding 
deployment, as weather and street conditions permit. In addition, the 
traffic lanes of all streets within the downtown core area of Steamboat 
Springs, as bounded by 3rd Street, 12th Street, Yampa, and Oak. These 
roadways must be swept within four days of the roadways becoming free 
and clear of snow and ice following each sanding deployment, as weather 
and street conditions permit.
    The State believes, and EPA agrees, that these contingency measures 
are adequate since the control measures implemented in the 
PM10 SIP provide a safety margin by achieving more emissions 
reductions than needed to demonstrate attainment of the PM10 
NAAQS, as indicated by the State's predicted 24-hour attainment 
concentration of 115 g/m\3\. For a detailed discussion of 
these contingency measures, see the TSD accompanying this document.
10. Emergency Episode Plan
    EPA believes the Steamboat Springs emergency episode plan, as 
included in the September 16, 1997 submittal, is adequate. The plan 
describes the actions to be taken when conditions exist that have 
historically resulted in exceedances of the 24-hour PM10 
standard. Voluntary and mandatory activities include suspension of open 
burning, curtailment of wood/coal burning, and reduction of non-
essential motor vehicle operations. For details on the emergency 
episode plan, please see the TSD.
11. Revisions to the Nonattainment Area Boundary
    The Steamboat Springs nonattainment area boundary as codified in 
the Federal Register notice published on December 21, 1993 (see 58 FR 
67334) is currently defined as the Steamboat Springs area airshed. See 
40 CFR 81.306. This boundary description was intended to be responsive 
to comments received from the State of Colorado on EPA's September 22, 
1992 proposed rulemaking to redesignate the area to nonattainment (see 
57 FR 43846). In those comments, the State indicated that on June 20, 
1991 the AQCC adopted a map which outlined the Steamboat Springs 
PM10 nonattainment area. The map identified the 
nonattainment area

[[Page 68194]]

as a portion of Routt County which included the City of Steamboat 
Springs, as well as certain surrounding areas in Routt County. With its 
PM10 SIP submittal dated August 12, 1996, the State provided 
a clearer description of the boundary by providing a legal description 
of the map outline. The following legal description of the 
nonattainment area represents the map outline adopted by the AQCC and 
used by APCD for SIP purposes:
    On the East--The Routt National Forest.
    On the South--The southern border of sections 19, 10, 21, T4N, R84W 
of the 6th P.M. and the southern border of sections 23, 24, T4N, R85W 
of the 6th P.M.
    On the West--Beginning at the south western corner of section 23, 
T4N, R85W of the 6th P.M. North along the western border of sections 
23, 14, 11, T4N, R85W. Thence, along the ridge which bisects sections 
35, 36, 25, 24, 13, 14, 11, 12, 1, T5N, R85W, and sections 36, 25, 24, 
T6N, R85W. Thence heading northwest along the ridge which bisects 
sections 23, 15, 10, 9,4, T6N, R85W of 6th P.M. Thence, heading 
northeast along the ridge which bisects sections 33, 34, 35, 36, 25, 
T7N, R85W and sections 30 and 10 of T7N, R84W. Thence, north along the 
N 1/2 of the western edge of section 19, to the NW corner of section 
18, T7N, R84W.
    On the North--The northern boundary of sections 16, 17, 18, T7N, 
R84W of 6th P.M.
    The boundary was determined to be the reasonable Steamboat Springs 
air shed by considering factors such as local topography, meteorology, 
emissions sources, land use practices, and tourism. EPA is replacing 
the boundary description currently in 40 CFR 81.306 with this revised 
description to more clearly define the nonattainment area.

B. Update to Code of Federal Regulations

    EPA is also updating 40 CFR 52.332, Moderate PM10 
nonattainment area plans, to reflect the approved status of the 
Telluride moderate PM10 nonattainment area plan. EPA 
approved that SIP on October 4, 1996 (61 FR 51784), but neglected to 
update 40 CFR 52.332 at that time.

III. Final Action

    EPA is approving the elements of the PM10 SIP for the 
Steamboat Springs, Colorado nonattainment area that were due on July 
20, 1995 and submitted to EPA by the Colorado Governor with a letter 
dated September 16, 1997, including among other things, control 
measures, technical analyses, quantitative milestones and contingency 
measures. Additionally, EPA is approving the Steamboat Springs 
emergency episode plan. EPA is also amending the boundary description 
for the Steamboat Springs nonattainment area to clarify the original 
description.
    Note that per an October 29, 1997 letter from the State, EPA is not 
acting on revisions to the Ambient Air Quality Standards for the State 
of Colorado which were included in the September 16, 1997 SIP submittal 
for informational purposes only.
    EPA is publishing this action without prior proposal because the 
Agency views this as a noncontroversial amendment and anticipates no 
adverse comments. However, in a separate document in this Federal 
Register publication, EPA is proposing to approve the SIP revision 
should adverse or critical comments be filed. This action will be 
effective March 2, 1998 unless, by January 30, 1998 adverse or critical 
comments are received.
    If EPA receives such comments, this action will be withdrawn before 
the effective date by publishing a subsequent document that will 
withdraw the final action. All public comments received will be 
addressed in a subsequent final rule based on this action serving as a 
proposed rule. EPA will not institute a second comment period on this 
action. Any parties interested in commenting on this action should do 
so at this time. If no such comments are received, the public is 
advised that this action will be effective on March 2, 1998.
    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 a SIP shall be 
considered separately in light of specific technical, economic, and 
environmental factors and in relation to relevant statutory and 
regulatory requirements.

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 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 
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 regulatory 
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. 
E.P.A., 427 U.S. 246, 256-66 (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 
the 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 proposes to 
approve pre-existing requirements under State or local law, and imposes 
no new Federal 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

    Under 5 U.S.C. 801(a)(1)(A) as added by the Small Business 
Regulatory Enforcement Fairness Act of 1996, EPA submitted a report 
containing this rule and other required information to the U.S. Senate, 
the U.S. House of

[[Page 68195]]

Representatives and the Comptroller General of the General Accounting 
Office prior to publication of this rule in today's 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 March 2, 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

40 CFR Part 52

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

40 CFR Part 81

    Air pollution control, National parks, Wilderness areas.

    Dated: November 4, 1997.
Jack W. McGraw
Acting Regional Administrator.

    40 CFR Parts 52 and 81 are 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.

    2. Section 52.320 is amended by adding paragraph (c)(76) to read as 
follows:


Sec. 52.320  Identification of plan.

* * * * *
    (c) * * *
    (76) The Governor of Colorado submitted the moderate nonattainment 
area PM10 State Implementation Plan (SIP) for Steamboat 
Springs, Colorado with a letter dated September 16, 1997. The submittal 
was made to satisfy those moderate PM10 nonattainment area 
SIP requirements due for Steamboat Springs on July 20, 1995, including 
among other things, control measures, technical analyses, quantitative 
milestones, and contingency measures. The September 16, 1997 submittal 
also included the Steamboat Springs emergency episode plan.
    (i) Incorporation by reference.
    (A) Colorado Air Quality Control Commission Nonattainment Areas, 5 
CCR 1001-20, Section VIII., Steamboat Springs PM10 
Nonattainment Area, adopted October 17, 1996 and effective on December 
30, 1996.
    (ii) Additional material.
    (A) An October 29, 1997 letter from Margie M. Perkins, APCD, to 
Richard R. Long, EPA, clarifying that the regulation entitled ``Ambient 
Air Quality Standards for the State of Colorado'' was included in the 
September 16, 1997 Steamboat Springs SIP submittal for informational 
purposes only.
* * * * *
    3. Section 52.329 is amended by revising paragraph (a) to read as 
follows:


Sec. 52.329  Rules and regulations.

    (a) On January 14, 1993, the Governor of Colorado submitted 
revisions to the State's nonattainment new source review permitting 
regulations to bring the State's regulations up to date with the 1990 
Amendments to the Clean Air Act. With these revisions, the State's 
regulations satisfy the part D new source review permitting 
requirements for the following nonattainment areas: the Canon City, 
Lamar, Pagosa Springs, Aspen, Telluride, and Steamboat Springs moderate 
PM10 nonattainment areas, the Denver/Metro Boulder, 
Longmont, Colorado Springs, and Fort Collins moderate carbon monoxide 
nonattainment areas, the Greeley not classified carbon monoxide 
nonattainment area, and the Denver transitional ozone nonattainment 
area.
* * * * *
    4. Section 52.332 is amended by adding paragraphs (g) and (h) to 
read as follows:


Sec. 52.332  Moderate PM10 nonattainment area plans.

* * * * *
    (g) On March 17, 1993, December 9, 1993, and April 22, 1996, the 
Governor of Colorado submitted the moderate PM10 
nonattainment area plan for Telluride. The submittals were made to 
satisfy those moderate PM10 nonattainment area SIP 
requirements which were due for Telluride on November 15, 1991. The 
December 9, 1993 submittal was also made to satisfy the PM10 
contingency measure requirements which were due for Telluride on 
November 15, 1993.
    (h) On September 16, 1997 the Governor of Colorado submitted the 
moderate PM10 nonattainment area plan for Steamboat Springs. 
The submittal was made to satisfy those moderate PM10 
nonattainment area SIP requirements which were due for Steamboat 
Springs on July 20, 1995.

PART 81--[AMENDED]

    1. The authority citation for part 81 continues to read as follows:

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

    2. In Sec. 81.306, the table for Colorado-PM10 
Nonattainment Areas is amended under Routt County (part) by revising 
the entry for ``The Steamboat Springs Area Airshed'' to read as 
follows:


Sec. 81.306  Colorado.

* * * * *

                                       Colorado--PM-10 Nonattainment Areas                                      
----------------------------------------------------------------------------------------------------------------
                                                     Designation                          Classification        
          Designated area           ----------------------------------------------------------------------------
                                        Date                  Type                  Date            Type        
----------------------------------------------------------------------------------------------------------------
                                                                                                                
                  *                  *                  *                  *                  *                 
                                      *                  *                                                      
Routt County (part)--Steamboat         1/20/94  Nonattainment..................    1/20/94  Moderate.           
 Springs.                                                                                                       
On the East--The Routt National                                                                                 
 Forest.                                                                                                        
On the South--The southern border                                                                               
 of sections 19, 10, 21, T4N, R84W                                                                              
 of the 6th P.M. and the southern                                                                               
 border of sections 23, 24, T4N,                                                                                
 R85W of the 6th P.M.                                                                                           

[[Page 68196]]

                                                                                                                
On the West--Beginning at the                                                                                   
 southwestern corner of section 23,                                                                             
 T4N, R85W of the 6th P.M. North                                                                                
 along the western border of                                                                                    
 sections 23, 14, 11, T4N, R85W.                                                                                
 Thence, along the ridge which                                                                                  
 bisects sections 35, 36, 25, 24,                                                                               
 13, 14, 11, 12, 1, T5N, R85W, and                                                                              
 sections 36, 25, 24, T6N, R85W.                                                                                
 Thence heading northwest along the                                                                             
 ridge which bisects sections 23,                                                                               
 15, 10, 9,4, T6N, R85W of 6th P.M.                                                                             
 Thence, heading northeast along                                                                                
 the ridge which bisects sections                                                                               
 33, 34, 35, 36, 25, T7N, R85W and                                                                              
 sections 30 and 10 of T7N, R84W.                                                                               
 Thence, north along the N \1/2\ of                                                                             
 the western edge of section 19, to                                                                             
 the NW corner of section 18, T7N,                                                                              
 R84W.                                                                                                          
On the North--The northern boundary                                                                             
 of sections 16, 17, 18, T7N, R84W                                                                              
 of 6th P.M.                                                                                                    
                                                                                                                
                  *                  *                  *                  *                  *                 
                                      *                  *                                                      
----------------------------------------------------------------------------------------------------------------

* * * * *
[FR Doc. 97-33958 Filed 12-30-97; 8:45 am]
BILLING CODE 6560-50-P