[Federal Register Volume 66, Number 114 (Wednesday, June 13, 2001)]
[Proposed Rules]
[Pages 31873-31878]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-14902]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 81

[CA-034-FIN; FRL-69964]


Clean Air Act Redesignation and Reclassification, Searles Valley 
Nonattainment Area; Designation of Coso Junction, Indian Wells Valley, 
and Trona Nonattainment Areas; Reclassification of Coso Junction and 
Indian Wells Valley Nonattainment Areas; California; Particulate Matter 
of 10 Microns or Less (PM-10)

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to change the boundaries of the Searles 
Valley, California moderate PM-10 nonattainment areas (NA) by dividing 
that area into three separate NAs: Coso Junction, Indian Wells Valley, 
and Trona. Because air quality violations or inadequate monitoring 
data, EPA is also proposing to find that the proposed Coso Junction and 
Indian Wells Valley NAs have not attained the 24-hour and annual PM-10 
national ambient air quality standards (NAAQS) by the Clean Air Act 
(CAA) mandated attainment date for moderate nonattainment areas. EPA is 
further proposing to find that the proposed Trona NA has attained the 
24-hour and annual NASQS.
    If EPA takes final action on this proposal, the Searles Valley NA 
would be split into three new NAs, and the Coso Junction and Indian 
Wells Valley NAs would be reclassified by operation of law as serious 
PM-10 NAs under section 188(b)(2)(A) of the CAA. The classification of 
the proposed Trona PM-10 NA would remain moderate.

DATES: Comments on this proposed action must be received in writing by 
August 13, 2001.

ADDRESSES: Comments should be addressed to John Ungvarsky, U.S. 
Environmental Protection Agency, Region 9, Air Division, Planning 
Office (AIR-2), 75 Hawthorne Street, San Francisco, California 94105.

FOR FURTHER INFORMATION CONTACT: John Ungvarsky, U.S. Environmental 
Protection Agency, Region 9, Air Division, Planning Office (AIR-2), 75 
Hawthorne Street, San Francisco, California 94105, (415) 744-1286, 
[email protected].

SUPPLEMENTARY INFORMATION:

I. Background

    The NAAQS are safety thresholds for certain ambient air pollutants 
set by

[[Page 31874]]

EPA to protect public health and welfare. PM-10 is among the ambient 
air pollutants for which EPA has established a health-based standard. 
PM-10 causes adverse health effects by penetrating deep in the lung, 
aggravating the cardiopulmonary system. Children, the elderly, and 
people with asthma and heart conditions are the most vulnerable.
    On November 15, 1990, the date of enactment of the 1990 Clean Air 
Act Amendments, PM-10 areas with PM-10 levels exceeding health 
standards and meeting the qualifications of section 107(d)(4)(B) of the 
Act were designated nonattainment by operation of law. Once an area is 
designated nonattainment, section 188 of the Act outlines the process 
for classification of the area and establishes the area's attainment 
date. Pursuant to section 188(a), all PM-10 nonattainment areas were 
initially classified as moderate by operation of law upon designation 
as nonattainment. These nonattainment designations and moderate area 
classification were codified in 40 CFR part 81 in a Federal Register 
notice published on November 6, 1991 (56 FR 56694). The Searles Valley 
planning area was designated nonattainment and classified as moderate. 
See 40 CFR 81.305.
    States containing areas which were designated as moderate 
nonattainment by operation of law under section 107(d)(4)(B) were to 
develop and submit state implementation plans (SIPs) to provide for the 
attainment of the PM-10 NAAQS by no later than December 31, 1994. 
Pursuant to section 189(a)(2), those SIP revisions were to be submitted 
to EPA by November 15, 1991.
    Situated at the southeastern end of the Sierra Nevada Mountains, 
the Searles Valley NA includes portions of three counties (i.e., Inyo, 
Kern, and San Bernardino) with its boundaries defined by United States 
Geological Survey (USGS) Hydrologic Unit #18090205, an area of 
approximately 2000 square miles. 40 CFR 81.305.
    Because of the nature of the PM-10 exceedances and the local 
jurisdictional boundaries within the NA, the California Air Resources 
Board (CARB) has historically treated the Searles Valley NA as three 
separate planning subregions. When the original moderate area SIP was 
developed in 1991, the PM-10 exceedances that formed the basis for the 
planning strategies were determined to be caused by local sources in 
each of the subregions.\1\
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    \1\ ``PM-10 State Implementation Plan for the Searles Valley 
Planning Area, Draft Final,'' November 1991, pages 2-7.
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    County boundaries have also played a major role in the 
apportionment of planning responsibilities and development of 
subregions within the Searles Valley NA. The Inyo County portion of the 
NA is under the jurisdiction of the Great Basin Air Pollution Control 
District (APCD) and is referred to as the Coso Junction subregion. The 
Kern County portion is under the jurisdiction of the Kern County APCD 
and is referred to as the Indian Wells Valley subregion.\2\ The San 
Bernardino County portion is under the jurisdiction of the Mojave 
Desert Air Quality Management District (AQMD) and is referred to as the 
Trona subregion.
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    \2\ Prior to 1997, this area was referred to as the China Lake 
subregion.
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    In October 1993, CARB submitted to EPA a moderate area SIP jointly 
developed by the Great Basin Unified APCD, Kern County APCD, and Mojave 
Desert AQMD. The affected districts asserted, and CARB concurred, that 
three distinct, localized and independent PM-10 problems existed in the 
Searles Valley NA.\3\ To support this division, CARB explained that the 
hydrologic zone that defines the boundaries of the NA actually 
encompasses three separate valleys. CARB indicated that the valleys are 
distinct from one another and do not appear to share the same PM-10 
exceedances and stated that localized strategies can be justified on 
the basis of geography and topography. See Boyd letter.\4\
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    \3\ Letter from James D. Boyd, Executive Officer, CARB, to 
Felicia Marcus, Regional Administrator, EPA Region IX, dated October 
28, 1993 (Boyd letter).
    \4\ Subsequent to the October 1993 submittal and in further 
support of the Districts' and CARB's assertion that the PM-10 
problems in the Searles Valley nonattainment area are distinct, on 
July 2, 1996, CARB submitted to EPA a redesignation request and 
maintenance plan for the Trona subregion, and on July 28, 1997, CARB 
submitted to EPA a redesignation request and maintenance plan for 
the Indian Wells Valley subregion. EPA is not acting on these 
submittals in today's notice.
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    Although CARB has historically treated the Searles Valley NA as 
three separate planning areas, they did not officially request the area 
be divided into three NAs until very recently.

II. Rationale for Establishing Coso Junction, Indian Wells Valley, 
and Trona as new Nonattainment Areas

A. CARB's Request

    On May 4, 2001, CARB submitted to EPA a request under CAA section 
107(d)(3)(D) to revise the boundaries for the Searles Valley NA by 
dividing the area into three separate PM-10 nonattainment areas, Coso 
Junction, Indian Wells Valley, and Trona, to be separated along the 
Inyo, Kern, and San Bernardino county lines within the Searles Valley 
NA. Together, the three proposed NAs would cover the same geographic 
area as the existing Searles Valley PM-10 NA.\5\
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    \5\ Letter from Michael Kenny, Executive Officer, CARB, to Laura 
Yoshii, Acting Regional Administrator, EPA Region IX, dated May 4, 
2001 (Kenny letter).
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    Under section 107(d)(3)(D), the Governor of any State, on the 
Governor's own motion, is authorized to submit to the Administrator a 
revised designation \6\ of any nonattainment area or portions thereof 
within the State. In determining whether to approve or deny a State's 
request for a revision to the designation of an area under section 
107(d)(3)(D), EPA uses the same factors Congress directed EPA to 
consider when the Agency initiates a revision to a designation of an 
area on its own motion under section 107(d)(3)(A). These factors 
include ``air quality data, planning and control considerations, or any 
other air quality-related considerations the Administrator deems 
appropriate.''

B. Air Quality Data and Related Considerations

    As discussed below, air quality data for the Searles Valley NA and 
analysis of wind patterns indicate that the recorded exceedances of the 
24-hour PM-10 NAAQS during the 1992 through 2000 \7\ time frame in the 
Coso Junction and Indian Wells Valley subregions are not the result of 
transport between the subregions in the NA area.
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    \6\ Boundary changes are an inherent part of a designation or 
redesignation of an area under the CAA. See CAA section 
107(d)(1)(B)(ii).
    \7\ Data for the 1992-2000 period is provided in IV.B as support 
for EPA's proposed division of the Searles Valley NA into three 
separate NAs. For purposes of the proposed findings discussed in 
sections IV and V of this notice, EPA is relying on data from the 
1992-1994 time frame.
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1. Coso Junction
    From April 1993 through May 1996, the Great Basin Unified APCD 
conducted a study of PM-10 transport from Owens Valley.\8\ The study 
showed that wind blown dust from the Owens Valley PM-10 nonattainment 
area, specifically emissions from the Owens (dry) Lake, contributed to 
the monitored exceedances at Coso Junction. The study documented that 
when exceedances occurred in Coso Junction, the winds were from the 
north. This factor alone eliminates the possibility of sources from 
Indian Wells Valley and Trona

[[Page 31875]]

contributing to the exceedances in Coso Junction since these subregions 
are located to the south of Coso Junction. Since the completion of the 
transport study, two exceedances occurred in the Coso Junction 
subregion. The Great Basin Unified APCD has indicated that at least one 
of these exceedances was attributed to wind blown dust from the Owens 
Valley NA.\9\
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    \8\ See letter from Duane Ono, Great Basin Unified APCD, to John 
Kennedy, EPA Region IX, dated March 26, 2001 (Ono letter) enclosing 
Owens Study.
    \9\ See Ono letter.
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2. Indian Wells Valley
    In April 1995 and March 1998, the Indian Wells Valley subregion 
exceeded the 24-hour PM-10 NAAQS. The 1995 exceedance was captured as 
part of the Great Basin Unified APCD's transport study and, like the 
same day exceedance at Coso Junction, appears to have been caused when 
winds were from the north, thus implicating Owens Lake in the adjacent 
Owens Valley NA, and not Trona sources, as a likely contributor to the 
exceedance. See Ono letter. The cause of the 1998 exceedance (165 ug/
m\3\) is currently being analyzed by CARB. In this instance, the 
exceedance occurred when winds were from the south, which eliminates 
the possibility of sources in Trono or Coso Junction contributing to 
the exceedance. In addition, the corresponding same-day PM-10 values in 
Coso Junction (21 ug/m\3\) and Trona (24 ug/m\3\) were well below the 
24-hour PM-10 NAAQS, an indication that the sources causing the 
exceedance in Indian Wells Valley did not impact PM-10 levels in the 
Coso Junction or Trono subregions.
3. Trona
    The Tronba subregion has not recorded an exceedance of the 24-hour 
PM-10 NAAQS since 1990.

C. Planning and Control Considerations

    Each of the subregions in the Searles Valley NA is associated with 
a separate valley in the NA. The corresponding topography of the 
valleys limits the transport of PM-10 emissions between the Searles 
Valley subregions. See Kenny letter. With the exception of transport of 
PM-10 from Owens Lake into Searles Valley, as described above, there is 
no indication or record of sources in any one subregion impacting PM-10 
levels in an adjacent subregion.
    The proposed Coso Junction NA corresponds with the current Coso 
Junction subregion planning area and the Rose Valley. The Rose Valley 
is bounded by the Coso Range to the east and south. The Sierra Nevada 
Range bounds the Valley to the west, and the intersection of the two 
ranges makes up the northern boundary.
    The proposed Indian Wells Valley NA corresponds with the current 
Indian Wells Valley subregion planning area and the Indian Wells 
Valley. This valley is bounded by the Argus Range to the east, the 
Sierra Nevada Range to the west. The El Paso Mountains bound the 
southern area, and the Coso Range closes off the northern end.
    The proposed Trona NA corresponds with the Trona subregion planning 
area and the Searles Valley, which contains the Searles (dry) Lake. 
This valley is bounded by the Slate Range to the east and Argus Range 
to the west. These two ranges join together at the north and south to 
fully encompass the Searles (dry) Lake. The Mojave Desert AQMD is 
primarily responsible for this subregion, although a small portion of 
Inyo County, which is under the jurisdiction of Great Basin Unified 
APCD, falls within the proposed Trona NA.
    These valleys are distinct from one another and do not share the 
same PM-10 exceedances. As a result, separate NAs with localized 
strategies on the basis of the area's geography and topography are 
appropriate.
    In addition, as stated earlier, CARB's moderate area SIP 
incorporates an attainment strategy and demonstration for each of the 
respective subregions corresponding to the jurisdictions of the three 
local air districts. Subsequent SIP revisions for the Searles Valley NA 
have been prepared and adopted by the responsible air district in each 
subregion, each reflecting the unique contributors to nonattainment 
under its jurisdiction. These administrative and planning 
considerations further support CARB's request that the Searles Valley 
NA be divided into three separate NAs.
    Based on the State's request and consideration of the supporting 
factors described above, we are today proposing to change the 
boundaries for the Searles Valley NA by dividing the area into the Coso 
Junctiuon, Indian Wells Valley and Trona NAs reflecting the historical 
subregional divisions that have been in place since the early 1990's.

III. Proposed Boundaries for the Proposed Coso Junction, Indian 
Wells Valley and Trona Nonattainment Areas

    The proposed Coso Junction NA boundaries would consist of the 
portion of Inyo County contained within USGS Hydrologic Unit #18090205. 
The proposed Indian Wells Valley NA boundaries would include the 
portion of Kern County contained within USGS Hydrologic Unit #18090205. 
The proposed Trona NA boundaries would include the portion of the San 
Bernardino County contained within USGS Hydrologic Unit #18090205. The 
combination of these three proposed NAs would comprise the same area 
included in the Searles Valley NA as set forth in 40 CFR 81.305.

IV. Proposed Findings of Attainment and Nonattainment

A. Clean Air Act Requirements

    EPA has the responsibility, pursuant to sections 179(c) and 
188(b)(2) of the Act, of determining within 6 months of the applicable 
attainment date, whether PM-10 nonattainment areas have attained the 
NAAQS. Section 179(c)(1) of the Act provides that these determinations 
are to be based upon an area's ``air quality as of the attainment 
date,'' and section 188(b)(2) is consistent with this requirement. For 
the Searles Valley, the attainment date was December 31, 1994. 
Therefore, for purposes of the attainment finding, EPA must use 
monitoring data from 1992-1994. EPA makes the determinations of whether 
an area's air quality is meeting the PM-10 NAAQS based upon air quality 
data gathered at monitoring sites in the nonattainment area. These data 
are reviewed to determine the area's air quality status in accordance 
with EPA guidance at 40 CFR part 50, appendix K.
    Pursuant to appendix K, attainment of the annual PM-10 standard is 
achieved when the annual arithmetic mean PM-10 concentration is equal 
to or less than 50 g/m \3\. Attainment of the 24-hour standard 
is determined by calculating the expected number of exceedances of the 
150 ug/m \3\ limit per year. The 24-hour standard is attained 
when the expected number of exceedances is 1.0 or less. A total of 3 
consecutive years of clean air quality data are generally necessary to 
show attainment of the 24-hour and annual standards for PM-10.
    The proposed findings pursuant to CAA sections 179(c) and 188(b)(2) 
for the proposed Coso, Indian Wells Valley and Trona NAs are discussed 
below and are based on air quality data for 1992-1994, the 3 years up 
to and including the attainment deadline year. In addition, more recent 
data support our proposal.\10\
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    \10\ See Table 3.
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B. Ambient Air Monitoring Data

    As stated above, the 24-hour NAAQS 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. In 
general, the number of expected exceedances at a site which samples 
every day is determined by recording the number of exceedances in each 
calendar year and then averaging them over the past three

[[Page 31876]]

calendar years. For sites which do not sample every day, EPA requires 
the adjustment of observed exceedances to account for days not sampled. 
The procedures for making the adjustment are specified in 40 CFR part 
50, appendix K.
    In addition, an important consideration in making air quality 
determinations for both the 24-hour and annual standards is data 
completeness. A complete year of air quality data, as referred to in 40 
CFR part 50, appendix K, is comprised of all 4 calendar quarters with 
each quarter containing data from at least 75 percent of the scheduled 
sampling days. EPA requires pollutant data sets to be complete 
according to this definition in order for us to determine that an area 
is in attainment of the PM--10 NAAQS. For example, if an area samples 
for PM-10 on a one in six day sampling schedule, there would be 60-61 
samples scheduled to be collected in a given calendar year or 15-16 
samples in a calendar quarter. In order for a PM-10 data set to be 
deemed complete, an agency must collect 75 percent of the scheduled 
samples in a quarter. See 40 CFR part 50, appendix K.
    EPA recognizes that data from some scheduled sampling days may be 
missing for any number of reasons, e.g. damaged filters (sample loss), 
miscalibrated equipment, or other equipment failure. 40 CFR part 50, 
appendix K specifies a minimum 75 percent data capture rate of required 
PM-10 samples, but states that ``data not meeting these criteria may 
also suffice to show attainment, however, such exceptions will have to 
be approved by the Regional Administrator in accordance with 
established guidelines.''
    EPA has provided guidance on how and when the Agency can make 
attainment findings when the data capture rate is less than 75 percent 
per calendar quarter. See ``Guideline on Exceptions to Data 
Requirements for Determining Attainment of Particulate Matter 
Standards,'' Office of Air Quality Planning and Standards, April 1987 
(hereafter referred to as ``data substitution policy''). There are 
minimum criteria that must be met in order for EPA to utilize this 
policy. For areas that have two or more years of monitoring data, there 
must be at least 50 percent of the required samples in each quarter and 
at least one of the years must indicate attainment based on monitored 
concentrations that meet the minimum 75 percent data capture 
requirement. The policy may also be used if only one year of every day 
sampling is available and the data capture rate exceeds 75 percent in 
each quarter.
    In the case of the Searles Valley NA, there are three monitoring 
sites that need to be evaluated in our determination of the area's 
attainment status. In the 1992-1994 period, the sites in Coso Junction 
and Indian Wells Valley have at least one year that did not meet the 75 
percent data completeness criteria. Since none of the sites samples on 
an every day schedule, we need to evaluate whether they met the 
requirement of having at least 50 percent data capture for those 
quarters not meeting the 75 percent data capture requirement. The 
guidance document cited above allows for the substitution of missing 
data using monitored data from the same quarter in anyone of the years 
used to determine attainment. The maximum PM-10 value that was observed 
in that quarter over the attainment period may be substituted for 
missing scheduled sampling days, provided emissions and meteorology for 
these quarters are representative of the emissions and meteorology for 
the quarter in question.
    In evaluating the data for the proposed Coso, Indian Wells Valley 
and Trona NAs, EPA considered the actual recorded PM-10 concentrations 
for 1992-1994, the sampling frequency of the monitors used in the PM-10 
network, and the completeness of the data collected.
1. 24-hour Standard
    Table 1 presents a summary of the data collected for the 24-hour 
standard in the Searles Valley NA during 1992-1994.

                                      Table 1.--Summary of Searles Valley 24-hour PM-10 Air Quality Data 1992-1994
                                                  [NAAQS=50 micrograms per cubic meter (g/m3)]
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                                                       Maximum 24-
                                                           hour       Number of
               Site Name                     Year     concentration    observed         Number of estimated exceedances        Data 75 percent complete?
                                                       (g/  exceedances                                                          Y/N
                                                           m3)
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Coso Junction..........................         1992            38             0  Cannot be determined......................  No.
                                                1993           254             2  8.4.......................................  Yes.
                                                1994           388             1  4.1.......................................  Yes.
Indian Wells (China Lake)\11\..........         1992            39             0  Cannot be determined......................  No.
                                                1993            50             0  Cannot be determined......................  No.
                                                1994            26             0  Cannot be determined......................  No.
Trona..................................         1992           105             0  0.........................................  Yes.
                                                1993            79             0  0.........................................  Yes.
                                                1994           107             0  0.........................................  Yes.
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Source: Aerometric Information Retrieval System/Air Quality Subsystem (AIRS/AQS).

    Based on the air quality data presented above, EPA proposes to find 
that the proposed Coso NA did not attain the 24-hour PM-10 NAAQS during 
the 1992-1994 period.
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    \11\ As stated previously in this notice, in 1997 the China Lake 
subregion was renamed Indian Wells Valley. However the monitoring 
site which represents this subregion is still called China Lake in 
EPA's AIRS/AQS database.
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    For the proposed Indian Wells Valley NA, data collection was 
inadequate and the data substitution policy cannot be used because the 
monitor did not collect at lasts 50 percent of the scheduled samples 
during certain quarters in the 1992-1994 period. As a result, EPA 
cannot make a fining of attainment of the proposed Indian Wells Valley 
NA for the 24-hour standard and must propose instead to find that this 
area also failed to attain the 24-hour standard for the 1992-1994 
period.
    For the proposed Trona NA, EPA proposes to find that the area 
attained the 24-hour PM-10 NAAQS during the 1992-1994 period.

[[Page 31877]]

2. Annual Standard
    The 1992-1994 annual average for each monitoring site is provided 
in Table 2.

 Table 2.--Annual Average PM-10 Concentration (g/m\3\) for Searles Valley Nonattainment Area for 1992-
                                                      1994
                                           [NAAQS = 50g/m\3\]
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                                                                                                       3 year
                                                      Annual                                           annual
                Site name and year                    average      Data 75 percent complete? Y/N       average
                                                   (g/                                     (g/
                                                       m\3\)                                            m\3\)
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Coso Junction:
    1992.........................................           *14  No...............................  ............
    1993.........................................            28  Yes..............................           *22
    1994.........................................            23  Yes..............................  ............
Indian Wells (China Lake):
    1992.........................................           *21  No...............................  ............
    1993.........................................            23  No...............................           *20
    1994.........................................           *17  No...............................  ............
Trona:
    1992.........................................            37  Yes..............................  ............
    1993.........................................            37  Yes..............................            34
    1994.........................................            28  Yes..............................  ............
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* Because the data set for the year is not complete, an accurate annual average that meets EPA regulatory
  requirements cannot be calculated. Furthermore, since the Coso Junction and Indian Wells Valley monitoring
  sites have quarters which do not meet the minimum 50 percent capture rate, EPA cannot utilize the data
  substitution policy. The number reported here is simply based on the available data.
Source: Aerometric Information Retrieval System/Air Quality Subsystem (AIRS/AQS)

    The monitoring sites for the proposed Coso and Indian Wells Valley 
NAs did not meet the 75 percent data completeness requirement. 
Furthermore, some quarters of data at each site also did not meet the 
50 percent minimum data capture requirement. Therefore, EPA's data 
substitution policy cannot be used and EPA must propose to find that 
the proposed Coso Junction and Indian Wells Valley NAs failed to attain 
the annual standard for the 1992-1994 period.
    For the proposed Trona NA, EPA proposes to find that the area 
attained the annual standard during the 1992-1994 period.
3. Post-1994 Exceedances Support EPA's Proposed Action
    Exceedances of the 24-hour NAAQS \12\ occurring during the 1995 
through 2000 time frame in the proposed Coso Junction and Indian Wells 
Valley NAs are listed in Table 3. No exceedances were recorded during 
the period in the proposed Trona NA.
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    \12\ There were no recorded exceedances of the annual standard 
during the 1995-2000 period. However, as discussed in section 
IV.B.2, there are significant data gaps for both standards from 
1992-1994 which are relevant to the attainment status of the area.

Table 3.--Searles Valley NA Monitoring Sites Exceeding the 24-Hour PM-10
                         NAAQS During 1995-2000
                       [NAAQS=150 g/m\3\]
------------------------------------------------------------------------
                                                             Exceedance
                Site and Date of Exceedance                 (g/
                                                                m\3\
------------------------------------------------------------------------
Coso Junction, Rest Area on Hwy 395:
    4/8/95................................................           692
    4/21/95...............................................           337
    5/23/96...............................................           309
    3/18/98...............................................           409
Coso Junction 10 miles east of Coso Junction:
    4/9/95................................................           597
    4/21/95...............................................           268
    3/6/98................................................           246
Indian Wells Valley\13\ 100 Las Flores Ave, Ridge Crest:
    4/8/95................................................           235
Indian Wells Valley, Powerline Road, China Lake:
    3/23/98...............................................          165
------------------------------------------------------------------------
\13\ The Las Flores Avenue monitor was a special purpose monitor
  included in the Owens Lake transport study. It was sporadically
  operated during the 1993-1996 study, ``Air Quality Impacts Downwind of
  Owens Lake,'' by the Great Basin Unified APCD, June 1997 (Owens
  Study). EPA's policy on the use of special purpose monitoring data is
  described in an EPA memorandum entitled ``Agency Policy on the Use of
  Special Purpose Monitoring Data'' from John Seitz, Director, Office of
  Air Quality Planning and Standards, to the Regional Air Directors,
  August 22, 1997.

V. Proposed Reclassifications and SIP Requirements for Serious 
Areas

    Under CAA section 188(b)(2)(A), a moderate PM-10 nonattainment area 
must be reclassified as serious by operation of law after the statutory 
attainment date if the Administrator finds that the area has failed to 
attain the NAAQS. Pursuant to section 188(b)(2)(B) of the Act, EPA must 
publish a notice in Federal Register identifying those areas that 
failed to attain the standard and the resulting reclassifications. 
Because the Searles Valley moderate NA has a statutory deadline of 
December 31, 1994, EPA is required to base its original determination 
of whether the area attained the PM-10 standards on data from 1992-
1994. See section IV above. For this period, for both the 24-hour and 
annual standards, EPA is proposing to find that the proposed Coso 
Junction and Indian Wells Valley NAs did not attain. Because EPA is 
proposing to find that the proposed Trona NA attained the PM-10 
standards, it would remain a moderate NA.\14\
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    \14\ If EPA takes final action to create the Trona NA, the area 
would be redesignated to attainment upon approval by the Agency of a 
maintenance plan pursuant to CAA section 175A.
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    PM-10 nonattainment areas reclassified as serious under section 188 
(b) (2) of the CAA are required to submit, within 18 months of the 
Area's reclassification, SIP revisions providing for implementation of 
best available

[[Page 31878]]

control measures (BACM)\15\ and a major source definition of 70 tons 
per year. The SIP must also, among other things, provide for attainment 
of the PM-10 NAAQS by December 31, 2001.\16\ See CAA sections 188 (c) 
(2) and 189 (b). EPA has provided specific guidance on developing 
serious area PM-10 SIP revisions. See 59 FR 41998 (August 16, 1994).
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    \15\ BACM must be implemented no later than four years from the 
date of reclassification.
    \16\ If certain conditions are met, EPA may extend this 
attainment deadline to no later than December 31, 2006. CAA section 
188 (e).
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    Data from the most recent three year period (1998-2000) indicates 
the proposed Coso Junction and Indian Wells Valley NAs exceeded the PM-
10 24-hour NAAQs. The proposed Coso Junction NA recorded two exceedance 
in March, 1998, and the proposed Indian Wells Valley NA recorded an 
exceedance March, 1998. In their May 4, 2001 letter \17\ to EPA, CARB 
indicated that it is investigating whether the exceedance in Indian 
Wells Valley was caused by a natural event.\18\ Because of these 
exceedances, the proposed Coso Junction and Indian Wells Valley NAs do 
not qualify for redesignation at this time. In order for a 
nonattainment area to be redesignated to attainment, the area must have 
three years of clean data and meet the redesignation requirements of 
section 107 (b) (3) (E) of the CAA.\19\
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    \17\ See footnote 5.
    \18\ EPA's policy for an exceedance caused by a natural event is 
explained in a memorandum entitled ``Areas Affected by PM-10 Natural 
Events'' from Mary Nichols, Assistant Administrator for Air and 
Radiation, to the EPA Regional offices, May 30, 1996. The State is 
responsible for establishing a clear casual relationship between the 
exceedance and the natural event and submitting the documentation to 
EPA within 180 days of the exceedance, and, at a minimum, developing 
a Natural Events Action Plan within 18 months of the exceedances.
    \19\ Memorandum from John Calcagni to Regional Office Air 
Directors, ``Procedures for Processing Requests to Redesignate Areas 
to Attainment,'' September 4, 1992.
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VI. Summary of Today's Proposals

    In today's action, EPA is proposing to divide the Searles Valley NA 
into three, newly created NAs: Coso Junction, Indian Wells Valley, and 
Trona. EPA is also proposing to find that the proposed Coso Junction 
and Indian Wells Valley NAs did not attain the 24-hour and annual PM-10 
NAAQS.

VII. Request for Public Comment

    The EPA is requesting comment on any or all aspects of today's 
proposals. As indicated at the outset of this notice, EPA will consider 
any comments received by August 13, 2001.

VIII. Administrative Requirements

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), this 
proposed action is not a ``significant regulatory action'' and 
therefore is not subject to review by the Office of Management and 
Budget.
    Under section 188(b)(2) of the CAA, findings of failure to attain 
are based solely upon air quality considerations and the subsequent 
nonattainment area reclassification must occur by operation of law in 
light of those air quality conditions. These actions do not, in and of 
themselves, impose any new requirements on any section of the economy. 
In addition, because the statutory requirements are clearly defined 
with respect to the differently classified areas, and because these 
requirements are automatically triggered by classifications that, in 
turn, are triggered by air quality values, findings of failure to 
attain and reclassification cannot be said to impose a materially 
adverse impact on State, local, or tribal governments or communities. 
The proposed splitting of the Searles Valley NA into three new, 
separate NAs with a moderate classification will not impose any new 
requirements on any sectors of the economy because the area is already 
classified as moderate.
    Accordingly, the Administrator certifies that this proposed rule 
will not have a significant economic impact on a substantial number of 
small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et 
seq.).
    These proposed actions do not contain any unfunded mandate or 
significantly or uniquely affect small governments, as described in the 
Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4) for the following 
reasons: (1) The proposed finding of failure to attain is a factual 
determination based on air quality considerations; (2) the resulting 
reclassification must occur by operation of law and will not impose any 
federal intergovernmental mandate; and (3) the proposed splitting of 
the Searles Valley NA into three, new and separate NAs with a moderate 
classification will not impose any new requirements on any sectors of 
the economy. For the same reason, this proposed rule also does not have 
a substantial direct effect on one or more Indian tribes, on the 
relationship between the Federal Government and Indian tribes, or on 
the distribution of power and responsibilities between the Federal 
Government and Indian tribes, as specified by Executive Order 13175 (65 
FR 67249, November 9, 2000). For these same reasons, these proposed 
actions will not have substantial direct effects on the States, on the 
relationship between the national government and the States, or on the 
distribution of power and responsibilities among the various levels of 
government, as specified in Executive Order 13132 (64 FR 43255, August 
10, 1999). These proposed actions are also not subject to Executive 
Order 13045 (62 FR 19885, April 23, 1997). because they are not 
economically significant. Finally, for these same reasons, the 
requirements of section 12(d) of the National Technology Transfer and 
Advancement Act of 1995 (15 U.S.C. 272 note) do not apply.
    As required by section 3 of Executive Order 12988 (61 FR 4729, 
February 7, 1996), in issuing these proposed actions, EPA has taken the 
necessary steps to eliminate drafting errors and ambiguity, minimize 
potential litigation, and provide a clear legal standard for affected 
conduct. EPA has complied with Executive Order 12630 (53 FR 8859, March 
15, 1988) by examining the takings implications of the rule in 
accordance with the ``Attorney General's Supplemental Guidelines for 
the Evaluation of Risk and Avoidance of Unanticipated Takings'' issued 
under the executive order. These proposed actions do not impose an 
information collection burden under the provisions of the Paperwork 
Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

List of Subjects in 40 CFR Part 81

    Environmental protection, Air pollution control, National parks, 
Wilderness areas.

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

    Dated: June 5, 2001.
Laura Yoshii,
Acting Regional Administrator, Region IX.
[FR Doc. 01-14902 Filed 6-12-01; 8:45 am]
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