Clean Air Act Approval and Promulgation of PMINF10 Implementation Plan for Denver, CO, and the Denver Mobile Source Emissions Budgets for PMINF10 and NOINFX

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[CO-001-002; CO-001-003 and CO-001-004; FRL-5628-8]

Clean Air Act Approval and Promulgation of PM10

Implementation Plan for Denver, CO, and the Denver Mobile Source

Emissions Budgets for PM10 and NOX

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of proposed rulemaking.

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SUMMARY: EPA proposes approval of the state implementation plan (SIP)

revision submitted by Colorado on March 30, 1995, to achieve 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 (PM10) in the Denver area, including: Control

measures; technical analysis (e.g., emission inventory, and attainment)

and other Clean Air Act (Act) SIP requirements. The SIP revision was

submitted to satisfy certain Federal requirements for an approvable

moderate nonattainment area PM10 SIP for Denver and, among other

things, contains enforceable control measures.

EPA also proposes to approve the PM10 and NOX mobile

source emissions budgets for Denver that were submitted by the Governor

on July 18, 1995 and April 22, 1996, respectively.

DATES: Comments on the actions proposed in this document must be

received in writing by December 2, 1996.

ADDRESSES: Comments should be addressed to: Richard R. Long, Director,

Air Program (8P2-A), Environmental Protection Agency, Region VIII, 999

18th Street, Suite 500, Denver, Colorado 80202-2466. Label the comments

as comments addressing the Denver PM10, PM10 emissions budget

or NOX emissions budget SIPs.

Copies of the State's submittals and other information are

available for inspection during normal business hours at the following

locations: Environmental Protection Agency, Region VIII, Air Program,

999 18th Street, Denver, Colorado 80202-2466; and Colorado Air

Pollution Control Division, 4300 Cherry Creek Dr. South, Denver,

Colorado 80222-1530.

FOR FURTHER INFORMATION CONTACT: Callie Videtich, Air Program, EPA

Region VIII, 999 18th Street, Suite 500, Denver, Colorado 80220-2405 or

by phone at (303) 312-6434.

SUPPLEMENTARY INFORMATION:

I. Background

The Denver, Colorado area was designated nonattainment for

PM10 and classified as moderate under sections 107(d)(4)(B) and

188(a) of the Act, upon enactment of the Clean Air Act Amendments of

1990.1 See 56 FR 56694 (Nov. 6, 1991); and 40 CFR 81.306

(specifying PM10 nonattainment designation for the Denver

metropolitan area). The air quality planning requirements for moderate

PM10 nonattainment areas are set out in Part D, Subparts 1 and 4,

of Title I of the Act.2

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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\ 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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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 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

[[Page 51632]]

of the interpretations of Title I advanced in this proposal and the

supporting rationale. In this rulemaking action on the Colorado

moderate PM10 SIP for the Denver nonattainment area, EPA is

applying its interpretations considering the specific factual issues

presented.

Those States containing initial moderate PM10 nonattainment

areas (those areas designated nonattainment under section 107(d)(4)(B)

of the Act) were required to submit, among other things, the following

plan 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 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.

Some provisions were due at a later date. States with initial

moderate PM10 nonattainment areas were required to submit a new

source review (NSR) permit program for the construction and operation

of new and modified major stationary sources of PM10 by June 30,

1992 (see section 189(a)). On January 14, 1993, the State submitted

regulation revisions for the construction of new and modified major

stationary sources. On August 18, 1994, EPA partially approved the

State's NSR program for the Denver PM10 nonattainment area because

the State had not yet submitted NSR provisions for sources of PM10

precursors (i.e., NOX and SO2) in the Denver area (see 59 FR

42300). On August 25, 1994, Colorado submitted additional NSR

provisions for precursor emissions. EPA will be acting on that SIP

submittal in a separate notice.

States were also required to submit contingency measures for

PM10 moderate nonattainment areas by November 15, 1993. The

contingency measures for the Denver PM10 nonattainment area were

initially submitted by the Governor on December 9, 1993. However, those

measures were later incorporated into the revised March 30, 1995

PM10 SIP. Therefore, the State developed new contingency measures,

and on November 17, 1995, the Governor submitted those measures to EPA.

EPA is taking action on the contingency measures SIP submittal in a

separate rulemaking action.

On June 7, 1993, the Governor submitted a SIP for Denver to EPA

which was intended to satisfy those elements due November 15, 1991. On

December 20, 1993, EPA proposed to conditionally approve that SIP and

also proposed to approve the SIP's control measures for their limited

purpose of strengthening the Colorado SIP (58 FR 66326). On July 25,

1994, EPA granted limited approval of the control measures for the

limited purpose of strengthening the SIP (59 FR 37698).

During review of the technical information supporting the June 1993

SIP, EPA examined information which raised concern about the accuracy

of the SIP's attainment demonstration. The SIP's technical support

documentation suggested that the contribution from PM10

``precursors'' (i.e., nitrogen oxides and sulfur dioxides) in the base

year winter season may have been underestimated. Since the attainment

demonstration provided with that SIP predicted a value of 149.9

g/m3 over 24 hours, virtually any increase in precursor

PM10 levels would result in predicted violations of the 24-hour

standard.

In the December 20, 1993, proposed rulemaking action, EPA requested

public comment on it's proposal to grant conditional approval of the

SIP in light of the precursor issue. EPA reviewed the information

submitted during the public comment period and concluded that

precursors were underestimated by 5.4 g/m3. Based upon this

finding, EPA delayed taking final action on the proposed conditional

approval to allow the State an opportunity to develop additional

controls to offset this increase. On March 30, 1995, the Governor

submitted a SIP revision intended to provide controls to offset the

increase in precursor emissions and provide credible attainment and

maintenance demonstrations. On July 18, 1995, and April 22, 1996 the

Governor submitted additional revisions to the SIP which establish

mobile source emissions budgets for PM10 and NOX. The

conformity rule provides that these budgets establish a cap on motor

vehicle-related emissions which cannot be exceeded by the predicted

transportation system emissions in the future unless the cap is amended

by the State and approved by EPA as a SIP revision and attainment and

maintenance of the standard can be demonstrated.

Section 110(k) of the Act sets out provisions governing EPA's

review of SIP submittals (see 57 FR 13565-13566). EPA is taking three

actions with this document.

1. EPA is proposing to approve the revised Denver PM10 SIP, as

adopted by the Colorado Air Quality Control Commission (AQCC) October

20, 1994 with an amendment on December 15, 1994, and submitted by the

Governor of Colorado on March 30, 1995. This submittal contains, among

other things, several control measures, regulation and permit revisions

and attainment and three-year maintenance demonstrations. The State's

submittal demonstrates attainment of the PM10 NAAQS by December

31, 1994 3, with continued maintenance of the standard through

December 31, 1997.

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\3\ The Clean Air Act calls for attainment as expeditiously as

practicable but no later than December 31, 1994. Section 188(c)(1).

The State's submittal sometimes refers to December 31, 1994 as the

attainment date and at other times implies 1995 as the attainment

date. EPA interprets that when the State refers to attainment by

1995 it means attainment by January 1, 1995. EPA is proposing to

approve the State's demonstration on the basis of the de minimis

differential between the two dates and the fact that, at times, the

State refers to the attainment date as December 31, 1994. The State

should promptly inform EPA if EPA has in any manner misinterpreted

the date by which the State is projecting attainment in the Denver

Metropolitan nonattainment area.

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2. EPA is proposing to approve the Denver PM10 mobile source

emissions budget contained in the SIP revision adopted by the AQCC on

February 16, 1995, and submitted by the Governor on July 18, 1995.

3. EPA is proposing to approve the Denver NOX mobile source

emissions budget adopted by the AQCC on June 15, 1995, and submitted by

the Governor on April 22, 1996.

II. This Action

A. Analysis of March 30, 1995 Denver PM10 SIP 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

[[Page 51633]]

hearing.4 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. 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). 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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\4\ In addition, 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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After providing reasonable notice, the AQCC held a public hearing

on October 20, 1994, to entertain public comment on the implementation

plan for Denver. The plan was adopted following the public hearing. The

plan was further amended after a properly noticed public hearing of the

AQCC on December 15, 1994. On March 30, 1995, the Governor signed and

submitted the SIP revision to EPA. The SIP was deemed complete by

operation of law six months following submission of the plan by the

Governor.

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.5 The emissions inventory also should include a

comprehensive, accurate, and current inventory of allowable emissions

in the area (see, e.g., section 110(a)(2)(K)). Because the submission

of such inventories is a necessary adjunct of an area's attainment

demonstration (or demonstration that the area cannot practicably

attain), the emissions inventories must be received with the SIP

revision containing the demonstration (see 57 FR 13539).

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\5\ 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.

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Colorado submitted an emissions inventory for base year 1989 (based

on actual emissions) and an emissions inventory for attainment year

1995 6 (based on allowable emissions). The winter 1989 and 1995

inventories are intended to represent all sources of primary PM10,

as well as all sources of the PM10 precursors (nitrogen oxides and

sulfur dioxide (NOX and SO2)). The precursor emissions are

important because filter analyses performed in conjunction with

chemical mass balance modeling indicated that a significant portion

(35%) of the PM10 monitored consisted of secondary ammonium

sulfate and nitrate.

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\6\ See footnote 3.

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The wintertime 1989 base year inventory identified re-entrained

road dust (44%), wood burning (18%) and street sanding (8.5%) as the

principal contributors to primary PM10. Other primary PM10

sources include unpaved road dust contributing 12.5% and point sources

contributing 4% of the total primary PM10 inventory.

The secondary emissions, 35% of total PM10, are divided

between NOX and SO2. For wintertime 1989 base year NOX,

stationary sources contribute 40% of the total NOX emissions with

vehicle exhaust at 41% and natural gas from residential and commercial

usages at 11%. The prime sources of SO2 include stationary sources

with 92% of the total SO2 emissions and vehicle exhaust with 5%.

The wintertime 1995 attainment year inventory identified re-

entrained road dust (47%), wood burning (6%) and street sanding (7%) as

the principal contributors to primary PM10. Other primary

PM10 sources include unpaved road dust contributing 12% and point

sources contributing 9% of the total primary PM10 inventory.

The secondary emissions, 35% of total PM10, are divided

between NOX and SO2. For the wintertime 1995 attainment year

NOX, stationary sources contribute 44% of the total NOX

emissions with vehicle exhaust at 38% and natural gas from residential

and commercial usages at 10%. The prime sources of SO2 include

stationary sources with 97% of the total SO2 emissions and vehicle

exhaust with 1%.

EPA is proposing to approve the emissions inventory because it is

accurate and comprehensive, and provides a sufficient basis for

determining the adequacy of the attainment demonstration for the Denver

area consistent with the requirements of sections 172(c)(3) and

110(a)(2)(K) of the act. For further details see the Technical Support

Document (TSD) prepared for this action which is available for public

review at the address indicated at the beginning of this notice.

3. RACM (Including RACT)

As noted, initial moderate PM10 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)). The General Preamble contains a detailed discussion of

EPA's interpretation of RACM (including RACT) (see 57 FR 13539-13545

and 13560-13561).

On July 25, 1994, EPA took final rulemaking action to approve

controls found in the June 7, 1993 Denver PM10 SIP submittal. That

action approved controls for their limited ability to strengthen the

SIP under sections 110(k)(3) and 301(a) of the Act. In that rulemaking

action, EPA found that the control measures appeared to satisfy the

specific requirements to implement RACM/RACT. However, due to the

State's need to fulfill a commitment to revise two stationary source

permits and due to the question of whether the attainment demonstration

was reasonable in light of questions regarding precursor contributions

to the attainment demonstration, EPA did not take definitive action to

find that the measures met the RACM/RACT requirements. Following the

June 1993 submittal, the State fulfilled the commitment, and EPA

determined that the precursor contribution to the PM10 levels was

underestimated.

The March 30, 1995 SIP submittal contains an evaluation of the

emissions reduction programs found in the June 1993 submittal, and

enhancements to those programs needed to demonstrate attainment and

maintenance. These enhancements were needed due to the underestimation

of the precursor contribution in the June 1993 demonstration. EPA is

now able to make RACM/RACT determinations for the control programs

contained in the March 1995 SIP submittal.

The March 30, 1995 SIP revision identifies four source categories

as major contributors to the PM10 nonattainment problem in Denver.

The following Table identifies the source categories and their

respective control measures implemented across the nonattainment area,

as well as measures exclusive to the Central Business District (CBD).

Generally, the CBD is where exceedances of the standard have occurred

and, therefore, is an important focus for the implementation of some of

the control measures.

When comparing the 1989 base year actual emissions inventory to the

1995 attainment year allowable emissions inventory for the entire

nonattainment area there is actually an increase in PM10

emissions. This is due to the fact that the suburban area of Denver has

grown over the past several years. Nevertheless, the State demonstrates

timely attainment area-wide even with these emissions increases.

[[Page 51634]]

To show timely attainment of the standard, woodburning controls,

street sanding/sweeping controls and reductions in stationary source

emissions had to be developed. As a result of these controls, as well

as the other control strategies (described further in the TSD), the CBD

shows a total 9.45% reduction (269.7 tons/year) from base year 1989

(actuals) to the 1995 attainment year (allowables), and demonstrates

timely attainment of the standard.

Denver PM10 SIP Control Strategies

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Source category Control strategy

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Residential Wood Burning (Area-wide controls)......................... 1. High pollution day wood burning

restriction program and revisions.

2. Requirements that new or remodeled

construction use a new cleaner wood

burning approach.

3. Voluntary conversion program from

existing wood burning to cleaner

burning technology.

4. New stove/fireplace insert

certification.

5. Prohibit resale of used, uncertified

stoves.

Street Sanding and Sweeping of Paved Streets (Area-wide and CBD 1. Material specifications for street

controls). sanding material.

2. Local management plans.

3. Enhanced street sanding and sweeping

in Central Denver and the I-25

Corridor.

4. City/County of Denver and CDOT reduce

amount of street sanding material in

the Denver CBD and central Denver by

50% from base year 1989.

Stationary Sources (Area-wide controls)............................... 1. Emission limits at Purina Mills.

2. Emission limits at Electron

Corporation.

3. Regulation limits for precursor

emissions at Cherokee, Arapahoe and

Valmont power plants.

4. Emission limits for NOX and SO2 at

Coors Glass and Coors Brewery.7

5. Emission limits at Conoco Refining.

6. Restrictions on oil use.

Mobile Sources (Area-wide controls)................................... 1. Light duty vehicle, light duty truck

NOX standards.

2. Urban bus particulate standards.

3. Diesel fuel sulfur limits.

4. Regulation #11 Enhanced I/M.

5. Regulation #12 Diesel I/M.

6. Regulation #13 Oxy Fuels.

7. MAC light rail line.

8. Express bus service from Denver to

new Denver International Airport.

9. CommuterCheck program.

10. ECOPass.

11. CU Student bus pass.

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\7\ Emission limits for Coors Glass increase, while the limits for Coors Brewery decrease. While EPA believes

these revisions to the emissions limits are acceptable for meeting RACM/RACT requirements, EPA's proposed

action herein regarding these limits does not in any manner relieve these companies of the obligation to

comply with any nonattainment NSR permitting requirements that might apply to such changes in emissions

limits.

A more detailed discussion of the individual source contributions

and their associated control measures (including available control

technology) can be found in the TSD. EPA has reviewed the State's

documentation and proposes to conclude that it adequately justifies the

control measures that will be implemented. Therefore, by this document,

EPA is proposing to approve the Denver PM10 plan submitted by the

Governor on March 30, 1995, as meeting the RACM (including RACT)

requirement.

4. Demonstration

As noted, the initial moderate PM10 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. Colorado conducted an attainment

demonstration using dispersion modeling for primary PM10 and

proportional rollback modeling analysis for secondary particulate

concentrations for the Denver area. This demonstration indicates that

the NAAQS for PM10 will be attained in Denver by December 31,

1994, at a modeled concentration of 147.8 g/m3 and will

be maintained in future years. The 24-hour PM10 NAAQS is 150

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).

There have never been exceedances of the annual average PM10

standard in the Denver metro area; therefore, an attainment analysis of

the annual standard was not performed. Finally, EPA believes that the

controls adopted to protect the 24-hour standard are sufficient to

maintain the annual standard. The control strategy used to achieve the

24-hour standard is summarized in the section above titled ``RACM

(including RACT).'' For a more detailed description of the attainment

demonstration and the control strategy, see the TSD accompanying this

document.

5. PM10 Precursors

The control requirements which 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 in excess of 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 13539-13540 and 13541-13542).

An analysis of air quality and emissions data for the Denver

[[Page 51635]]

nonattainment area demonstrates that exceedances of the PM10 NAAQS

are attributable both to direct particulate matter emissions from wood

burning, street sanding/sweeping, mobile sources, and stationary

sources, and to mobile and stationary source precursor emissions.

Further, the dispersion and chemical mass balance modeling for base

year 1989 identified precursor emissions of NOX and SO2 as

contributing 35% to the ambient PM10 concentration. Consequently,

major stationary sources of these precursors are required to comply

with all control requirements of the PM10 nonattainment area plan

which apply to major stationary sources of PM10 (i.e, RACT for

moderate areas and NSR permitting control requirements).

As indicated above, EPA proposes to approve the State's submittal

as meeting RACM (including RACT). EPA's proposed approval of RACT

extends to those control requirements applicable to the major

stationary sources of PM10 precursors. Specifically, EPA proposes

to find that the emission limits and restrictions on oil use are

reasonable and approvable because they provide for timely attainment of

the PM10 NAAQS. Additionally, these measures will help ensure

maintenance of the NAAQS.

On August 25, 1994, Colorado submitted NSR provisions for

precursors in the Denver nonattainment area. EPA is acting on that SIP

submittal in a separate notice. Further discussion of the data and

analyses addressing the contribution of precursor sources in this area

is contained in the TSD accompanying this document.

6. Quantitative Milestones and Reasonable Further Progress (RFP)

The PM10 nonattainment area plan revisions demonstrating

attainment must contain quantitative milestones which are to be

achieved every three years until the area is redesignated attainment

and which demonstrate RFP toward attainment by December 31, 1994 (see

sections 171(1) and 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 considering the quantitative milestones 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

PM10 NAAQS by December 31, 1994 (see section 171(1) of the Act).

EPA is proposing to approve the PM10 SIP for the Denver

nonattainment area as demonstrating attainment by December 31, 1994.

EPA is also proposing to approve the submittal as satisfying the

initial quantitative milestone requirement 8 and proposes to find

that the emissions reductions projected meet RFP.

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\8\ The emissions reduction progress made prior to the

attainment date of December 31, 1994 (only 46 days beyond the

November 15, 1994 milestone date) will satisfy the first milestone

requirement (57 FR 13539). The de minimis timing differential makes

it administratively impracticable to require separate milestone and

attainment demonstrations.

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Further, the State has demonstrated that continued maintenance of

the standard will be achieved through implementation of the control

measures found in the SIP. The State's roll-forward analysis indicated

that the highest predicted concentration is 149.9 g/m3.

Concentrations over 150 g/m3 violate the NAAQS.

The assurance that the initial milestone and reasonable further

progress will be achieved is based upon the State implementing the

particular control measures contained in the SIP which are addressed in

section II. A. 3. ``RACM (including RACT)'' of this document.

Consequently, EPA is approving these control measures as meeting RACM

(including RACT) and thus is also proposing to approve the SIP as

meeting the initial milestone and reasonable further progress

requirements.

7. Enforceability Issues

All measures and other elements in the SIP must be enforceable by

the State and EPA (see sections 172(c)(6) and 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) signed by 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) of the Act).

The State of Colorado has a program that will ensure that the

measures contained in the SIP are adequately enforced. In addition to

the specific authority cited under descriptions of the control

measures, the State's Attorney General has provided an opinion citing

the authorities contained in the Colorado Air Pollution Prevention and

Control Act which provide the State with the authority to enforce state

air regulations against local entities, and enforce local air pollution

requirements when local entities fail to do so. This is consistent with

section 110(a)(2)(E) of the Act.

The Air Pollution Control Division (APCD) has the authority to

implement and enforce all emission limitations and control measures

adopted by the AQCC, as provided for in C.R.S. 25-7-111. In addition,

C.R.S. 25-7-115 provides that the APCD shall enforce compliance with

the emission control regulations of the AQCC, the requirements of the

SIP, and the requirements of any permit. Civil penalties of up to

$15,000 per day per violation are provided for in C.R.S. 25-7-122 for

any person in violation of these requirements, and criminal penalties

are provided for in C.R.S. 25-7-122.1. Thus, the APCD has adequate

enforcement capabilities to ensure compliance with the Denver PM10

SIP and the State-wide regulations.

The particular control measures contained in the SIP apply to the

types of activities identified earlier and in the following discussion,

including: residential wood burning; street sanding/sweeping; mobile

sources; and reductions of emissions from stationary sources. As

explained in the following discussion, the control measures are

enforceable. Accordingly, EPA is proposing to approve the control

measures. The TSD contains further information about enforceability

requirements, including a discussion of the personnel and funding

intended to support effective implementation of the control measures.

a. Residential Wood Burning Controls. 1. High Pollution Day Wood

Burning Restrictions: Regulation No. 4 requires the APCD to implement

and enforce wood burning restrictions in areas which did not have local

enforceable ordinances before January 1, 1990. To ensure proper

enforcement, the APCD contracts with local health departments to

execute the enforcement provisions of the Regulation. In communities

where local ordinances regulating wood burning were in place prior to

January 1, 1990, the local government is responsible for enforcement of

its ordinance, including issuing fines, penalties, warnings, and

conducting inspections. (Local ordinances cover approximately 85% of

the Denver metro area.) The State has authority to enforce local

ordinances in place prior to January 1, 1990, if local governments fail

to do so.

2. Clean Wood Burning Technology for New or Remodeled Construction:

Beginning on January 1, 1993, state law

[[Page 51636]]

requires that new or remodeled fireplaces in new or remodeled

structures must be gas appliances, electric devices, or low emissions

fireplace inserts meeting the EPA Phase II New Source Performance

Standard (NSPS) or State adopted Phase III requirements. (EPA's Phase

II and Colorado's Phase III requirements are equivalent.) Under the

law, the fireplace restrictions must be adopted as building code

revisions by each local government and be enforced through the normal

code enforcement programs of each community. This requirement became

effective on January 1, 1993.

3. Encourage Conversion of Existing Wood Burning Units to Cleaner

Burning Technology: Legislation passed in 1992, required that the lead

air quality planning organization (the Regional Air Quality Council)

develop and implement a financial incentive program to provide

subsidies toward the purchase of new cleaner technologies.

Additionally, retailers must report the number of purchases of

certified stoves or inserts, and gas or electric fireplaces to the

Colorado Department of Revenue and submit a $1 fee for each

certification of conversion. Under the program, the Department of

Revenue is responsible for tracking conversions to cleaner

technologies, reported by retailers, and reporting the status of the

conversion program to the AQCC.

4. New Stove and Fireplace Insert Certification: State law

prohibits the resale and/or installation of any uncertified wood

burning device in the metro Denver area after January 1, 1993. The law

is enforced through the building code provisions of the various local

governments within the Denver area.

b. Street Sanding and Cleaning Controls. 1. Material Specifications

for Street Sanding Material: Regulation No. 16 sets specifications for

fines and durability of new and recycled sanding materials, and

requires that sand providers and users conduct testing and report the

quality of sanding materials and amounts used during the winter season

to the APCD. The Regulation is enforced through authority provided to

the State by statute.

2. Local Management Plans: Regulation No. 16 requires State and

local agencies that apply street sand to develop and submit a plan for

reducing their use of sand by 20% from 1989 base year levels. The

agencies are required to adopt ordinances or resolutions to support the

plans, to submit the plans by September 30, 1993, and to implement the

plans by November 1, 1993. The agencies are also required to submit

annual reports to the APCD documenting the reductions in sand use

achieved through implementation of the plans. The Regulation is

enforced through authority provided to the State by statute.

3. Further Enhancements to Street Sanding and Sweeping Practices in

the Denver CBD and Central Denver Area: Regulation No. 16 also requires

that the City and County of Denver reduce the amount of street sanding

material applied to all regional arterials, principal arterials and

main arterials within the Denver CBD by a total of 50 percent from 1989

base sanding amounts for these roadways. The revision also requires

that the Colorado Department of Transportation (CDOT) increase its

reduction in applied street sanding material from 20 percent to an

equivalent 50 percent on state-maintained freeways and ramps within the

Denver CBD. CDOT and the City/County are allowed to implement an

alternative plan to achieve an equivalent reduction through increased

sweeping and use of alternative deicers and/or sanding material,

subject to review and approval by APCD. EPA will review and concur by

letter on the alternative plans prior to APCD approval. EPA will not

consider such plans valid absent EPA concurrence. The Regulation is

enforced through authority provided to the State by statute.

c. Mobile Source Emission Reduction Measures. The SIP contains a

variety of mobile source control measures included in the 1990 Clean

Air Act Amendments in addition to the street sanding and sweeping

controls. These mobile source measures include the new light-duty

vehicle, light-duty truck NOX standards, urban bus particulate

standards, and diesel fuel sulfur limitations. Particulate emission

reductions are also incorporated for three existing State programs, the

enhanced inspection and maintenance program, the diesel inspection and

maintenance program, and the oxygenated fuels program (Regulations 11,

12 and 13). These programs were developed independently from the

PM10 SIP but are included because of their particulate matter

reduction benefit. The Act-required programs are enforced by the

federal government while the State regulations are enforced by the

APCD.

The SIP also includes a number of transportation control measures

to slow growth in vehicle miles traveled. These are not measures that

were developed specifically for the SIP, but measures that are already

planned or underway in the Denver area and accounted for in the mobile

source modeling for the attainment year. These measures are assumed to

be implemented by 1995 and have been included in the transportation

modeling supporting the attainment and maintenance demonstrations. The

Regional Transportation District (RTD) is implementing these measures

through its Transit Development Plan which has been adopted by the RTD

Board of Directors.

The measures for which the SIP takes credit within the

transportation modeling include the MAC Light Rail Line and additional

express bus service to the new Denver International Airport. Also,

several programs aimed at attracting new ridership are being

implemented. These new programs include the CommuterCheck program,

ECOPass, and the CU Student Pass Program. Through the implementation of

these and other marketing programs, transit ridership is expected to

increase by 20% between 1989 and 1995. A complete description of the

measures included in the SIP is found in section VIII of the SIP.

The Act requires that all federally funded transportation measures

be included in a conforming Regional Transportation Plan and

Transportation Improvement Program (TIP). Because the implementation of

these measures must conform to the SIP, any changes to the federally

funded measures included in the attainment demonstration must go

through a conformity analysis before they can be implemented. The

existing TIP has been found to conform with the SIP.

d. Stationary Source Measures. To control emissions from stationary

sources, APCD enforces both permit limitations and regulations through

authority provided under State statute. See the discussion under

section II.D. contained in the TSD for more information on the permit

and regulation revisions at stationary sources.

Rules and controls relating to woodburning, street sanding/

cleaning, mobile sources, and stationary sources are in effect now.

Colorado has a program that will ensure that the measures contained in

the Denver PM10 SIP are adequately enforced. EPA proposes to find

that the air enforcement program is adequate. The TSD contains further

information on enforceability responsibilities, 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

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generally 57 FR 13510-13512 and 13543-13544). These measures must be

submitted by November 15, 1993, for the initial moderate nonattainment

areas. 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

PM10 NAAQS by the applicable statutory deadline. Colorado chose to

submit the contingency measures separately from the PM10 SIP

requirements addressed in this document. The contingency measures for

the Denver PM10 nonattainment area were initially submitted by the

Governor on December 9, 1993. However, those measures were later

incorporated into the revised March 30, 1995 PM10 SIP. Therefore,

the State developed new contingency measures, and on November 17, 1995,

the Governor submitted those measures to EPA. EPA is taking action on

the contingency measures SIP submittal in a separate rulemaking action.

B. Denver PM10 Emissions Budget

On February 16, 1995, the AQCC adopted the Denver PM10 mobile

source emissions budget into the Colorado ``Ambient Air Quality

Standards'' following a properly noticed public hearing. On July 18,

1995, the Governor submitted a SIP revising certain Chapters of the

Denver PM10 SIP submitted on March 30, 1995, to include the Denver

PM10 mobile source emissions budget.

The EPA must determine whether a submittal is complete and

therefore warrants further EPA review and action (see section 110(k)(1)

and 57 FR 13565 and EPA's completeness criteria for SIP submittals set

out at 40 CFR Part 51, Appendix V). EPA did not make its completeness

determination within six months of receiving the submission. Thus, the

submittal was deemed complete by operation of law.

The Denver mobile source PM10 emissions budgets are being used

to assess the conformity of transportation plans, transportation

improvements programs, and where appropriate, federally funded projects

for the applicable periods indicated. The Denver PM10 mobile

source emissions budget was set for 1995 (41.2 tons/day), 1996-1997 (44

tons/day), 1998-2005 (54 tons/day) and 2006 and beyond (60 tons/day).

(The State was able to demonstrate attainment and maintenance of the

PM10 standard using the 1995 and 1996-1997 PM10 mobile source

emissions budgets.) The State adopted the PM10 revisions to the

Ambient Air Standards Emissions Budget to make them state enforceable.

EPA is proposing that the PM10 emissions budgets are approvable.

(See the TSD prepared for this action for more information.)

C. Denver NOX Emissions Budget

On April 22, 1996, the Governor submitted a SIP which contained an

amendment to the Colorado ``Ambient Air Quality Standards.'' The

amendment incorporated the NOX emissions budget for the Denver

PM10 nonattainment area and was adopted by the AQCC following a

properly held public hearing on June 15, 1995.

EPA reviewed the documentation as provided in accordance with

section 110(k)(1) and 57 FR 13565 and EPA's completeness criteria for

SIP submittals set out at 40 CFR Part 51, Appendix V. EPA found the

submittal complete, and advised the Governor of that finding in a

letter on July 15, 1996.

The 1995 and beyond NOX budget of 119.4 tons per day was used

in the March 30, 1995 PM10 SIP. (The State was able to demonstrate

attainment and maintenance of the PM10 standard using the NOX

mobile source emissions budget.) The State adopted the NOX

revisions to the Ambient Air Quality Standards Emissions Budget to make

it state enforceable. EPA is proposing that the NOX emissions

budget is approvable. (See the TSD prepared for this action for more

information.)

III. Proposed Action

EPA is proposing to approve the following: the revised Denver

PM10 SIP submitted by the Governor of Colorado on March 30, 1995;

the Denver PM10 mobile source emissions budget submitted by the

Governor on July 18, 1995; and the Denver NOX mobile source

emissions budget submitted by the Governor on April 22, 1996.

The EPA is requesting comments on all aspects of this proposal. As

indicated elsewhere in this document, EPA will consider any comments

received by December 2, 1996 on the appropriateness of the proposed

approval action on the Denver PM10 SIP, the Denver PM10

mobile source emissions budget, and the Denver NOX mobile source

emissions budget.

IV. Executive Order 12866

This action has been classified as a Table 3 action for signature

by the Regional Administrator under the procedures published in the

Federal Register on January 19, 1989 (54 FR 2214-2225), as revised by a

July 10, 1995, memorandum from Mary Nichols, Assistant Administrator

for Air and Radiation. The Office of Management and Budget (OMB) has

exempted this regulatory action from E.O. 12866 review.

V. 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 sections 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

this proposed Federal SIP approval does not impose any new

requirements, I certify that it does not have a significant impact on

any small entities affected. Moreover, due to the nature of the

Federal-State relationship under the CAA, preparation of a flexibility

analysis would constitute Federal inquiry into the economic

reasonableness of state action. The CAA 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).

VI. 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 also determined that this proposed action does not include

a Federal mandate that may result in estimated costs of $100 million or

more to State, local, or tribal governments in the aggregate, or to the

private sector. This Federal action approves pre-

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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 form this

action.

List of Subjects in 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.

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

Dated: September 13, 1996.

Patricia D. Hull,

Acting Regional Administrator.

[FR Doc. 96-25230 Filed 10-2-96; 8:45 am]

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