[Federal Register Volume 60, Number 56 (Thursday, March 23, 1995)]
[Proposed Rules]
[Pages 15269-15270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-6926]

[[Page 15269]]


40 CFR Part 52


Transportation Conformity; Proposed Approval of Petition for 
Exemption From Nitrogen Oxides Provisions, Colorado

AGENCY: Environmental Protection Agency.

ACTION: Proposed rule.


SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve a petition that was submitted pursuant to section 182(f) of the 
Clean Air Act (as amended in 1990) (CAA) by the Denver Regional Council 
of Governments (DRCOG) requesting that the Denver metropolitan area, an 
ozone nonattainment area classified as transitional, be exempted from 
the requirements regarding the control of oxides of nitrogen (NOX) 
imposed by the Federal conformity rules. These rules waive certain 
NOX requirements if an exemption under section 182(f) is granted 
by EPA. The EPA has indicated in relevant guidance that areas 
(including transitional areas, like the Denver Metropolitan area) 
demonstrating attainment based on ambient air quality monitoring data 
without additional NOX reductions satisfy the exemption test.

DATES: Comments must be received on or before April 24, 1995.

ADDRESSES: Written comments should be addressed to: Douglas M. Skie, 
Chief, Air Quality Branch (8ART-AP), United States Environmental 
Protection Agency, Region VIII, 999 18th Street, suite 500, Denver, 
Colorado 80202-2466.
    Copies of the DRCOG petition and other information relevant to this 
action are available for inspection between 8 a.m. and 4 p.m. Monday 
through Friday at the following locations: United States Environmental 
Protection Agency, Region VIII, Air Quality Branch (8ART-AP), 999 18th 
Street, suite 500, Denver, Colorado 80202-2466.
    Air and Radiation Docket and Information Center, United States 
Environmental Protection Agency, 401 M. Street SW., Washington, DC 
    Anyone wishing to review this petition at the Denver EPA Regional 
office is asked to contact the person below to schedule an appointment 
24 hours in advance.

(8ART-AP), Air Programs Branch, United States Environmental Protection 
Agency, Region VIII, 999 18th Street, Suite 500, Denver, Colorado, 
80202-2466, telephone (303) 294-1379.


I. Background

    Section 182(f) of the Clean Air Act contains requirements for major 
stationary NOX sources in marginal and above ozone nonattainment 
areas and in an ozone transport region. Section 182(f) also specifies 
circumstances under which the NOX requirements would be limited or 
would not apply.
    Under section 182(f)(1)(A), an exemption from the NOX 
requirements may be granted for nonattainment areas outside an ozone 
transport region if EPA determines that ``additional reductions of 
NOX would not contribute to attainment'' of the ozone NAAQS in 
those areas. EPA has indicated that in cases where a nonattainment area 
is demonstrating attainment with 3 consecutive years of air quality 
monitoring data, without having implemented the section 182(f) NOX 
provisions, it is clear that this test is met since ``additional 
reductions of NOX would not contribute to attainment'' of the 
NAAQS in that area.
    EPA's general and transportation conformity rules reference the 
section 182(f) exemption process as a means for exempting affected 
areas from certain NOX conformity requirements. See 58 FR 62197, 
November 24, 1993, Transportation Conformity, and 58 FR 63240, November 
30, 1993, General Conformity.
    This interpretation is discussed in a May 27, 1994 memorandum from 
John S. Seitz, Director, Office of Air Quality Planning and Standards 
(OAQPS), entitled ``Section 182(f) Nitrogen Oxides (NOX) 
Exemptions--Revised Process and Criteria.'' This memorandum revised 
relevant portions of previously-issued OAQPS guidance dated December, 
1993, entitled ``Guideline for Determining the Applicability of 
Nitrogen Oxide Requirements under Section 182(f).'' Both documents 
address EPA's policy regarding NOX exemptions for areas outside an 
ozone transport region that have air quality monitoring data showing 
attainment. The section 182(f) NOX provisions and the guidance 
cited above apply to marginal and above ozone nonattainment areas, but 
not nonclassifiable ozone nonattainment areas (i.e., submarginal, 
transitional, and incomplete/no data). However, on June 17, 1994, EPA 
published a document entitled ``Conformity; General Preamble for 
Exemption from Nitrogen Oxides Provisions'' (59 FR 31238) (``General 
Preamble''). This document provides guidance on the exemption of 
nonclassifiable ozone nonattainment areas, outside an ozone transport 
region, from the conformity rule's NOX provisions based on air 
quality monitoring data showing attainment. As a transitional ozone 
nonattainment area, the Denver metropolitan area falls within the 
``nonclassifiable'' category.
    Pursuant to section 182(f), a person or State may petition EPA to 
grant an exemption which would relieve the relevant nonattainment area 
from certain requirements of the general and transportation conformity 
rule. DRCOG submitted a NOX exemption petition on May 25, 1994 and 
submitted supporting documentation via a letter dated August 1, 1994. 
Ambient air quality data provided with the DRCOG petition showed no 
violations of the ozone NAAQS during the three-year period from 1991 
through 1993. Further, the Colorado Air Pollution Control Division 
(APCD) provided additional air quality data for the same time period 
supporting DRCOG's position that there were no violations.

II. Analysis of the DRCOG Petition for a NOX Exemption

    EPA believes that DRCOG has demonstrated that the Denver 
metropolitan area qualifies for an exemption from the NOX 
conformity requirements based on the ambient data provided by DRCOG and 
APCD for 1991, 1992, and 1993. The AIRS data show no violations of 
ozone NAAQS during these three years.
    The APCD has endorsed the DRCOG petition in a letter dated December 
15, 1994, from Tom Getz, Director, APCD, to Mr. William Yellowtail, the 
EPA Region VIII Regional Administrator.

III. Analysis of Other Ozone Network Issues

    EPA considered the condition of the ozone ambient air monitoring 
network as part of evaluating the DRCOG NOX exemption request. In 
1989, EPA called attention to suspected deficiencies in the ozone 
ambient air monitoring network. EPA and the APCD have continued to 
address these concerns over the years. The APCD conducted studies of 
the ozone network in 1991 and 1992. A 1993 study report noted that the 
network was not measuring at maximum concentrations. The APCD found 
that the maximum concentration area covered the northwest and southwest 
parts of the ozone nonattainment area. The state is required to 
designate at least one site, but should include as many as are 
necessary, to adequately monitor the maximum concentration area. (40 
CFR Part 58).
    In 1993, it was determined that higher values appeared in the 
northwest part of [[Page 15270]] the maximum concentration area rather 
than in the southwest. Priority was given to placing new sites in the 
    In 1993, APCD added two new sites in the northwest--Enrel and South 
Boulder Creek. No violations were recorded at these two sites in 1993. 
However, data in AIRS show one exceedance at the South Boulder Creek 
site in 1993. Three exceedances must occur for there to be a violation.
    These two new sites were retained and studied in 1994. The APCD has 
reported that no violations or exceedances occurred at either of these 
sites in 1994.
    There are nine sites currently on the Denver ozone ambient air 
monitoring network, including the two new sites. The Enrel and South 
Boulder Creek sites continue to record higher values than other sites 
on the network. The one exceedance at the South Boulder Creek site in 
1993 and the continued higher value readings at the same site and at 
the Enrel site confirm study findings that these sites are within the 
maximum concentration area and should remain in place.
    Modifying the network to ensure monitoring of maximum 
concentrations is an EPA priority and is required by 40 CFR part 58. 
The EPA is working with APCD to ensure that at least one monitoring 
site is established in the southwest area in 1995. In addition, the 
APCD plans to conduct further study in this southwest area during the 
1995 summer ozone season to more accurately identify where sites should 
be placed.
    Although there have been concerns with the monitoring network, EPA 
believes that many of the concerns have been corrected and that any 
remaining concerns are not significant enough to deny the NOX 
waiver. As indicated above, no violations have been recorded by the 
network, even since installation of the Enrel and South Boulder Creek 
sites in 1993. In addition, the NOX waiver policy published in the 
General Preamble provides further protection by providing for granting 
a NOX exemption on a contingent basis as described in section IV 
of this Federal Register document. This allows EPA to revoke the 
exemption if violations are recorded at any monitoring sites.

IV. Approval of the NOX Exemption on a Contingent Basis

    According to the General Preamble, approval of an exemption based 
solely on ambient air quality monitoring data shall be granted on a 
contingent basis, i.e., the exemptions will last for only as long as 
the area's monitoring data continue to demonstrate attainment. If EPA 
subsequently determines that the area has violated the ozone standard, 
the exemption, as of the date of the determination, will no longer 
apply. If a violation of the ozone NAAQS is monitored in the Denver 
Metropolitan Area, EPA will provide notice in the Federal Register. 
Existing transportation plans and TIPs and past conformity 
determinations will not be affected by a determination that the 
NOX exemption no longer applies, but new conformity determinations 
would have to observe the NOX requirements of the conformity rule. 
The State must continue to operate an appropriate ambient air quality 
monitoring network, in accordance with 40 CFR Part 58, to verify the 
attainment status of the area. The air quality data relied on for the 
above determination must be consistent with 40 CFR part 58 requirements 
and other relevant EPA guidance, and recorded in EPA's AIRS national 
    The EPA NOX exemption guidelines, published in the General 
Preamble, do not require that a redesignation request be submitted with 
a request for a NOX transportation conformity exemption. 
Conditional exemptions from the transportation conformity NOX 
requirements do not substitute for the redesignation process.
    The General Preamble stated that for areas which are relying on 
monitoring data for the exemption request, the notice proposing 
approval of the exemption request should provide opportunity for 
comment on the preliminary interpretations contained in the General 
Preamble. It should also offer opportunity for comment on the 
appropriateness of using monitoring data which are consistent with the 
requirements in 40 CFR part 58 and are recorded in AIRS as the basis of 
EPA's approval and rescission of the contingent NOX exemption. 
Accordingly, EPA requests comments regarding these matters.

V. Impacts of Granting a NOX Waiver for Denver Metropolitan 

    In ozone nonattainment areas classified as transitional, such as 
the Denver metropolitan area, the effect of a NOX exemption is 
limited solely to the issue of whether such areas may be exempted from 
meeting the applicable NOX requirements of the transportation and 
general conformity rule.
    EPA also stated in the General Preamble that it plans to amend the 
transportation conformity rule to require that once an area's 
maintenance plan is approved, any previously approved NOX 
conformity exemption no longer applies. The area must then demonstrate 
as part of its conformity determinations that the transportation plan 
and TIP are consistent with the motor vehicle emissions budgets for 
NOX where such a budget is established by the maintenance plan. As 
currently written, none of the transportation conformity rule's 
NOX requirements would ever apply to an area once such an area had 
received a NOX transportation conformity exemption.

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 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 
    This proposal does not create any new requirements. Therefore, I 
certify that it does not have 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 
    The OMB has exempted these actions from review under Executive 
Order 12866.
    Interested parties are invited to comment on all aspects of this 
proposed action.

List of Subjects in 40 CFR Part 52

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

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

    Dated: March 10, 1995.
William P. Yellowtail,
Regional Administrator.
[FR Doc. 95-6926 Filed 3-22-95; 8:45 am]