[Federal Register Volume 64, Number 13 (Thursday, January 21, 1999)]
[Proposed Rules]
[Pages 3263-3271]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-1124]


=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[AZ 009-FIP FRL-6221-3]
RIN 2060-A122


Revision to Promulgation of Federal Implementation Plan for 
Arizona--Maricopa Nonattainment Area; PM-10

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: Under the authority of section 110(c)(1) of the Clean Air Act 
(CAA or ``the Act''), EPA is proposing amendments to the moderate area 
federal implementation plan (FIP) for the Phoenix PM-10 nonattainment 
area (63 FR 41326, August 3, 1998). These amendments would modify the 
fugitive dust rule to add or replace certain test methods, include 
coverage of unpaved roads neither owned nor maintained by a public 
entity and allow alternative control measures (ACMs) to be implemented 
without prior EPA approval.
    EPA recently established a new standard for PM-2.5 and also revised 
the PM-10 standards; however, today's action does not address those 
standards.

DATES: Written comments will be accepted until March 8, 1999. EPA does 
not currently plan on holding a public hearing. If EPA receives a 
significant number of requests for a public hearing on the contents of 
today's proposal, EPA will schedule and notify the public of the 
hearing in a separate notice.

ADDRESSES: Written comments on EPA's proposed FIP amendments must be 
received by EPA at the address below. Comments should be submitted (in 
duplicate if possible) to: EPA Region 9, 75 Hawthorne Street (AIR4), 
San Francisco, CA 94105, Attn. Karen Irwin.
    A copy of docket No. A-98-42 containing material relevant to EPA's 
proposed action is available for review at: EPA Region 9, Air Division, 
75 Hawthorne Street, San Francisco, CA 94105. Interested persons may 
make an appointment with Eleanor Kaplan (415) 744-1159 to inspect the 
docket at EPA's San Francisco office on weekdays between 9 a.m. and 4 
p.m.
    A copy of the docket No. A-98-42 is also available to review at the 
Arizona Department of Environmental Quality, Library, 3033 N. Central 
Avenue, Phoenix, Arizona 85012. (602) 207-2217.
    Electronic Availability: This document is also available as an 
electronic file on EPA's Region 9 Air Web Page at http://www.epa.gov/
region09/air.

FOR FURTHER INFORMATION CONTACT: Karen Irwin (415) 744-1903.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Purpose of Today's Proposal
II. Summary of Proposed Amendments
    A. Test Methods
    1. Adding a silt content test method for unpaved roads and 
unpaved parking lots
    2. Adding a new visible crust test method or replacing the 
visible crust test method for vacant lots
    3. Adding a procedure to the standing vegetation test method for 
vacant lots
    B. Unpaved Roads
    C. Alternative Control Measures
III. Administrative Requirements
    A. Executive Order (E.O.) 12866
    B. Executive Order 12875
    C. Executive Order 13045
    D. Executive Order 13084
    E. Regulatory Flexibility Analysis
    F. Unfunded Mandates Reform Act (UMRA)
    G. Paperwork Reduction Act
    H. National Technology Transfer and Advancement Act (NTTAA)

I. Purpose of Today's Proposal

    On August 3, 1998 (63 FR 41326), EPA finalized a FIP for the 
Phoenix PM-10 nonattainment area (the ``final FIP''). Readers should 
refer to 63 FR 41326 for details of the history and contents of the 
final FIP.
    The final FIP includes a fugitive dust rule to control PM-10 
emissions from vacant lots, unpaved parking lots and unpaved roads 
codified at 40 CFR Sec. 52.128 (63 FR 41326, 41350), hereafter referred 
to as ``the final FIP rule''.1 Today's proposal addresses 
only the specific provisions related to the test methods, the 
alternative control measures (ACMs) and the unpaved road requirements 
of the final FIP rule as discussed below. EPA will accept comments only 
on the proposed amendments to these FIP rule provisions and not on any 
other aspects of the final FIP.
---------------------------------------------------------------------------

    \1\ EPA promulgated the fugitive dust rule as part of its court-
ordered obligation to provide for the implementation of Reasonably 
Available Control Measures (RACM) (required by section 189(a)(1)(C) 
of the Clean Air Act) in the Phoenix PM-10 nonattainment area.
---------------------------------------------------------------------------

    As promulgated on August 3, 1998 (63 FR 41326), the final FIP rule 
contains test methods for ascertaining compliance with the FIP's 
emission requirements. EPA has conducted additional technical field 
work in Phoenix on these test methods. While the test methods in the 
final FIP were the best available methods known to EPA at the time of 
promulgation, additional analysis has indicated others may be more 
accurate and comprehensive. In today's proposal, EPA is proposing and 
accepting comment on additional, new test methods for the FIP rule.
    EPA is also proposing to eliminate the requirement to submit ACMs 
to EPA for approval in order to remove an unnecessary administrative 
burden on the regulated community. Finally, EPA is proposing to require 
privately owned and privately maintained unpaved roads to meet the same 
RACM requirements as roads that are owned or maintained by a public 
entity.

II. Summary of Proposed Amendments

A. Test Methods

1. Adding a Silt Content Test Method for Unpaved Roads and Unpaved 
Parking Lots
    The final FIP rule contains an opacity standard of twenty (20) 
percent, or Ringlemann 1, for unpaved roads and unpaved parking lots. 
Compliance with this standard is to be tested using visible emissions 
test methods included in the final Phoenix FIP rule.2 Field 
testing has identified certain circumstances where

[[Page 3264]]

this test method may be difficult to use. Consequently, EPA is 
proposing an additional, new test method that the Agency believes may 
be more appropriate and accurate for testing compliance of fugitive 
dust sources covered under the final FIP rule.
---------------------------------------------------------------------------

    \2\ Reference Method 9 (40 CFR part 60, appendix A) and Methods 
203A and 203C. Appendix A.I. to Sec. 52.128 (63 FR 41326, 41353-
41355).
---------------------------------------------------------------------------

    The new test method involves measuring silt content on unpaved 
roads and unpaved parking lots according to a sieve field procedure. 
The emission rate of fine particles is proportional to silt content 
(amount of fine particles in any given soil sample), such that the 
higher the silt content the higher the propensity for a source to 
release fine particles. The proposed sieve field procedure to measure 
silt content on unpaved roads and unpaved parking lots involves 
collecting a sample from the source in an area the size of one square 
foot using a brush and dustpan. The sample is weighed, placed into a 
stack of sieves with various mesh openings and shaken vigorously for 
one minute. Material that collects in the bottom of the unit is weighed 
and its silt content estimated using simple calculations provided in 
the proposed test method. EPA successfully conducted the proposed silt 
content test method in the Phoenix nonattainment area. The proposed 
silt content standards associated with the sieve test method are six 
(6) percent or less for unpaved roads and eight (8) percent or less for 
unpaved parking lots. These standards are based on laboratory analysis 
of samples taken from unpaved sources in the Phoenix nonattainment area 
during EPA's field tests.3
---------------------------------------------------------------------------

    \3\ Field tests were conducted on May 27-28, 1998. Results from 
the field tests can be found in the document titled ``Analysis of 
Results from Field Tests in the Phoenix Nonattainment Area'' by 
Chatten Cowherd, MRI Research Institute, 425 Volker Blvd., Kansas 
City, Missouri, June 12, 1998.
---------------------------------------------------------------------------

    EPA is also proposing an alternative to conducting the silt content 
test method. Samples collected from sources may be taken to an 
independent testing laboratory for silt content analysis according to 
an EPA AP-42 test method.4 This option would provide 
additional flexibility to owners and operators of unpaved roads and 
unpaved parking lots.
---------------------------------------------------------------------------

    \4\ ``Procedures For Laboratory Analysis Of Surface/Bulk Dust 
Loading Samples'', (Fifth Edition, Volume I, Appendix C.2, 1995), 
AP-42, Office of Air Quality Planning & Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North 
Carolina.
---------------------------------------------------------------------------

    EPA is taking comment on this proposed additional test method, 
which is expected to provide greater compliance certainty under all 
circumstances. A source in violation of either the rule's existing 
opacity standard or the proposed silt content standard would not be in 
compliance with the rule. Since this additional test method may 
alleviate the need for the existing opacity test method, EPA is also 
accepting comment on whether or not to retain the opacity test method 
in the final FIP rule.
2. Adding a New Visible Crust Test Method or Replacing the Visible 
Crust Test Method for Vacant Lots
    The final FIP rule's test method for measuring visible crust 
thickness on vacant lots involves breaking off a piece of crust, 
checking whether the crust crumbles easily and measuring its thickness 
with a ruler.5 EPA received public comments suggesting that 
this test method would not always confirm the existence of a 
stabilizing crust. During field testing in Arizona, EPA attempted both 
the current test method and an alternative test method that was 
suggested by EPA's contractor.6 EPA believes the alternative 
test method would accomplish the same objective as the current test 
method, be similarly easy to use, more accurately repeatable by various 
parties, and more indicative of whether a sufficiently stabilizing 
crust exists. The alternative test method involves dropping a small 
steel ball from a height of one foot in select areas and checking to 
see whether the ball penetrates the surface or causes loose grains to 
appear. If so, this indicates that the crust is too thin to resist 
wind. A source in violation of either the existing or proposed visible 
crust standard would not be in compliance with the rule. EPA is 
accepting public comment on whether this alternative visible crust test 
method should be used in addition to or in place of the existing 
visible crust test method.
---------------------------------------------------------------------------

    \5\ 63 FR 41326, 41355.
    \6\ Chatten Cowherd, MRI Research Institute, 425 Volker Blvd., 
Kansas City, Missouri.
---------------------------------------------------------------------------

3. Adding a Procedure to the Standing Vegetation Test Method for Vacant 
Lots
    The final FIP rule contains a test method for standing 
vegetation.7 In this method, the vegetation is counted 
within a survey area and its average dimensions measured. During field 
tests conducted in Arizona,8 EPA noted that some vegetation 
was less dense than others. Density affects vegetation's ability to 
protect against wind erosion. Without providing additional guidance on 
how to measure a plant or weed's dimensions taking density into 
account, EPA is concerned that the existing standing vegetation test 
methods would not necessarily be accurately conducted and repeated by 
different individuals to achieve the same results. Therefore, EPA is 
proposing to add a procedure involving the use of a grid with one inch 
or half-inch squares to help ensure that various vegetative structures 
can be assessed accurately and consistently.9 This procedure 
would apply only when open air space exists within a plant or weed's 
perimeter. The proposed changes include minor clarifications to the 
standing vegetation test method.
---------------------------------------------------------------------------

    \7\ 63 FR 41326, 41356. Testing for standing vegetation is not 
necessary where a visible crust exists. However, if a disturbed 
surface area fails the visible crust test and standing vegetation is 
present, the lot may actually be stabilized depending on the extent 
to which the vegetation protects against wind erosion. The inclusion 
of more than one test method for vacant lots in the FIP rule adds 
compliance flexibility to sources by acknowledging that a disturbed 
surface does not necessarily need to be crusted in order to be 
stabilized if it contains sufficient vegetation or its soil has a 
high wind-resistance threshold. In fact, the FIP rule allows a 
disturbed vacant lot surface to be deemed stabilized if it meets 
just one out of a total of five criteria for stability.
    \8\ May 27-28, 1998.
    \9\ The procedure was provided to EPA by Larry Hagen, 
Agricultural Engineer, United States Department of Agriculture, Wind 
Erosion Research Unit, 2004 Throckmortion Hall, Kansas State 
University, Manhatten, Kansas 66506.
---------------------------------------------------------------------------

B. Unpaved Roads

    In the final FIP rule, EPA finalized requirements for unpaved roads 
that are publicly owned and/or operated (i.e. maintained). This 
includes privately owned roads that are publicly maintained. EPA is 
proposing to include in the FIP rule unpaved privately owned roads that 
are privately maintained or not maintained. However, roads on which 
public access is not allowed or that have fewer than 250 average daily 
trips (ADT) would remain exempt. The purpose of this proposed 
modification is to ensure that all public access roads with ADT levels 
of 250 or greater are controlled, regardless of whether a public entity 
owns or maintains them.10 Roads which would be covered under 
this proposal that are not currently covered under the final rule 
include:
---------------------------------------------------------------------------

    \10\ Note: haul roads are permitted sources under Maricopa 
County Environmental Services Division's rule 310. A haul road would 
only be subject to the FIP rule requirements if it is not a 
permitted source under Rule 310, has an ADT level of 250 or greater 
and is publicly accessible.
---------------------------------------------------------------------------

    Privately owned roads that are privately maintained; and
    Privately owned roads that are not maintained.
    EPA is also proposing to clarify the definition of an unpaved road 
as that used by motor vehicles or off-road motor vehicles.
    While EPA does not generally expect the newly added types of roads 
to meet or exceed 250 ADT, EPA is proposing that the FIP rule cover any 
such potential sources. It is EPA's intention

[[Page 3265]]

to eliminate the public or private classification of the owner/operator 
as a factor in whether the road is controlled. As discussed above, EPA 
does not expect that there will be many roads which will be newly 
covered under the FIP rule as a result of this change because most 
unpaved roads which are not publicly accessible nor publicly maintained 
are not likely to have a high level of ADT. It should also be noted 
that the classification of the owner/operator as public or private is 
not a factor in the other two source categories covered under the FIP 
rule--namely unpaved parking lots and vacant lots. The RACM 
implementation deadline for all existing unpaved roads would remain 
consistent with the current deadline for publicly owned or operated 
roads (June 10, 2000).
    EPA requests comment on the potential effects of extending control 
requirements to privately owned public access roads that are also 
privately maintained. EPA anticipates receiving additional information 
on the extended coverage of roads due to this proposal by the end of 
this year.11 When available, EPA will disseminate this 
information to the public and take it into consideration along with any 
comments received on this proposal before finalizing requirements on 
privately owned/maintained public access roads.
---------------------------------------------------------------------------

    \11\ EPA has entered into a contract with Pacific Environmental 
Services to collect information on the number, location and owners/
operators of unpaved roads, unpaved parking lots and disturbed 
vacant lots potentially covered under the FIP rule requirements.
---------------------------------------------------------------------------

C. Alternative Control Measures

    In the final FIP rule, ACMs are allowed provided that they are 
submitted to EPA and receive EPA approval.12 ACMs are any 
RACM not specifically listed in the rule that can meet the rule's 
stabilization standards for each source category.13 EPA is 
proposing to amend the final FIP rule such that ACMs will not require 
prior EPA approval. EPA believes that since the FIP rule contains test 
methods which indicate whether a surface is stabilized, owners/
operators can be allowed flexibility as to the type of RACM applied as 
long as the control measure results in a stabilized 
surface.14 Elimination of prior EPA approval for ACMs will 
decrease the FIP rule's implementation cost insofar as regulated 
parties will not need to commit time and resources in preparing ACMs 
and submitting them to EPA.
---------------------------------------------------------------------------

    \12\ 63 FR 41326, 41352.
    \13\ The ACM provisions of the rule do not otherwise authorize 
any modification of the FIP rule's requirements.
    \14\ Owners/operators may not, however, use dust suppressants 
that are prohibited by local, state or federal laws or regulations.
---------------------------------------------------------------------------

    The elimination of the requirement to submit ACMs for prior EPA 
approval will not affect the owners'/operators' responsibility to 
implement RACM. In fact, by emphasizing the intended result, as opposed 
to the type of control, EPA hopes to increase owners'/operators' 
understanding that their responsibility under the FIP rule will remain 
until a source is controlled even if the owner/operator attempts a 
control measure that fails to stabilize the surface.

III. Administrative Requirements

A. Executive Order (E.O. 12866)

    Under Executive Order 12866, 58 FR 51735 (October 4, 1993), the 
Agency must determine whether the regulatory action is ``significant'' 
and therefore subject to Office of Management and Budget (OMB) review 
and the requirements of the Executive Order. The Order defines 
``significant regulatory action'' as one that is likely to result in a 
rule that may:
    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local or tribal governments or communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Due to potential novel policy issues this action is considered a 
significant regulatory action and therefore must be reviewed by OMB. 
Changes made in response to OMB suggestions or recommendations will be 
documented in the public record.

B. Executive Order 12875

    Under E.O. 12875, EPA may not issue a regulation that is not 
required by statute and that creates a mandate upon a state, local, or 
tribal government, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by those 
governments. If EPA complies by consulting, Executive Order 12875 
requires EPA to provide to the Office of Management and Budget a 
description of the extent of EPA's prior consultation with 
representatives of affected state, local, and tribal governments, the 
nature of their concerns, copies of written communications from the 
governments, and a statement supporting the need to issue the 
regulation. In addition, E.O. 12875 requires EPA to develop an 
effective process permitting elected officials and other 
representatives of state, local, and tribal governments ``to provide 
meaningful and timely input in the development of regulatory proposals 
containing significant unfunded mandates.''
    Today's rule does not create a mandate on state, local or tribal 
governments. The rule does not impose any enforceable duties on these 
entities. Accordingly, the requirements of section 1(a) of E.O. 12875 
do not apply to this rule.

C. Executive Order 13045

    Protection of Children from Environmental Health Risks and Safety 
Risks (62 FR 19885, April 23, 1997), applies to any rule that: (1) is 
determined to be ``economically significant'' as defined under E.O. 
12866, and (2) concerns an environmental health or safety risk that EPA 
has reason to believe may have a disproportionate effect on children. 
If the regulatory action meets both criteria, the Agency must evaluate 
the environmental health or safety effects of the planned rule on 
children, and explain why the planned regulation is preferable to other 
potentially effective and reasonably feasible alternatives considered 
by the Agency.
    This rule is not subject to E.O. 13045 because it does not involve 
decisions intended to mitigate environmental health or safety risks.

D. Executive Order 13084

    Under E.O. 13084, EPA may not issue a regulation that is not 
required by statute, that significantly affects or uniquely affects the 
communities of Indian tribal governments, and that imposes substantial 
direct compliance costs on those communities, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by the tribal governments. If EPA complies by 
consulting, Executive Order 13084 requires EPA to provide to the Office 
of Management and Budget, in a separately identified section of the 
preamble to the rule, a description of the extent of EPA's prior 
consultation with representatives of affected tribal governments, a 
summary of the nature of their concerns, and a statement supporting the 
need to issue the regulation. In addition,

[[Page 3266]]

Executive Order 13084 requires EPA to develop an effective process 
permitting elected and other representatives of Indian tribal 
governments ``to provide meaningful and timely input in the development 
of regulatory policies on matters that significantly or uniquely affect 
their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. This action does not involve 
or impose any requirements that affect Indian Tribes. Accordingly, the 
requirements of section 3(b) of E.O. 13084 do not apply to this rule.

E. Regulatory Flexibility Analysis

1. Regulatory Flexibility Act Requirements
    Under the Regulatory Flexibility Act (RFA), 5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA), whenever EPA is required to publish notice of general 
rulemaking, EPA must prepare an initial regulatory flexibility analysis 
(IRFA) describing the economic impact of the proposal on small 
entities, unless the Administrator certifies that a proposed 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.
    For the purposes of this inquiry, as it applies to the proposed 
amendments to the federal fugitive dust rule (40 CFR Sec. 52.128), EPA 
is assuming that the affected or potentially affected sources 
constitute ``small entities'' as defined by the RFA.
    A detailed discussion of the RFA analysis for the final FIP is 
found in section V.B. at 63 FR 41326. In general, the proposed 
amendments to the final FIP fugitive dust rule are intended to provide 
more flexibility in complying with the FIP rule and to improve the test 
methods as they currently exist in the rule. Thus, EPA believes that 
the amendments will not change the final FIP RFA analysis, except 
possibly to have a lesser impact on small entities.
2. RFA Analysis
    a. Proposed Amendments to Federal Rule for Unpaved Roads, Unpaved 
Parking Lots and Vacant Lots. EPA believes that the proposed test 
method amendments will provide either more flexibility or an improved 
procedure for determining compliance with the FIP fugitive dust rule. 
The proposed silt content test method would allow persons who are not 
certified in visible emissions training to test the stability of an 
unpaved road or unpaved parking lot by using an alternative method to 
the opacity test method. EPA plans to ensure that the necessary sieve 
units are available for loan by local entities to regulated sources. 
Also, the proposed visible crust test method accomplishes the same 
objective as the current visible crust test method yet is more 
practical and can be accurately repeated by various parties. Finally, 
the proposed additional procedure to assist parties in measuring 
frontal silhouette area of various vegetative structures are merely 
intended to address circumstances that may arise in the field which are 
not addressed in the final FIP rule.
    For unpaved roads, EPA is proposing to include unpaved roads that 
are not owned or operated by public entities. However, roads on which 
public access is not allowed or that have fewer than 250 ADT would 
remain exempt. EPA intends to simply eliminate the public or private 
classification of the owner/operator as a factor in whether the road is 
controlled. As discussed earlier, EPA does not expect that there will 
be many roads which will be newly covered under the FIP rule as a 
result of this change because most unpaved roads which are not publicly 
accessible or publicly maintained are not likely to have a high level 
of ADT.
    Finally, EPA is today proposing to amend the final FIP rule such 
that ACMs will not require prior EPA approval. This proposed change 
would add to the rule's flexibility for source owners/operators and 
reduce the paperwork burden of the rule.
    b. Certification. For reasons discussed above, EPA has determined 
that it is not necessary to prepare a regulatory flexibility analysis 
in connection with the proposed rule amendments. After consideration of 
the economic impacts of today's proposed rule amendments on small 
entities, I hereby certify that the proposed rule will not have a 
significant economic impact on a substantial number of small entities.

F. Unfunded Mandates Reform Act (UMRA)

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), P.L. 
104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector.
    A detailed discussion of the UMRA requirements and how they are 
addressed can be found in section V.C. of the final FIP rulemaking (63 
FR 41326). As explained above, today's proposed amendments to the final 
FIP fugitive dust rule are intended to provide more flexibility in 
complying with the FIP rule and to improve the test methods currently 
in the rule. Thus, EPA believes that the amendments will not change the 
final FIP UMRA analysis, except possibly to have a lesser impact on the 
regulated entities.

G. Paperwork Reduction Act

    The proposed test method and ACM amendments do not impact the 
information collection request analysis for the final FIP (EPA ICR 
1855.02). For the proposed unpaved roads amendment, EPA does not 
generally expect the newly added types of roads for inclusion in the 
FIP rule to exceed the ADT de minimis level. Thus, in general, EPA 
believes that the proposed amendments to the final FIP rule do not 
affect the information collection requirements (EPA ICR 1855.02). The 
final FIP (63 FR 41326) provides more information on the information 
collection request requirements.

H. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Pub L. No. 104-113, Sec. 12(d) (15 U.S.C. 272 
note) directs EPA to use voluntary consensus standards in its 
regulatory activities unless to do so would be inconsistent with 
applicable law or otherwise impractical. Voluntary consensus standards 
are technical standards (e.g., materials specifications, test methods, 
sampling procedures, and business practices) that are developed or 
adopted by voluntary consensus standards bodies. The NTTAA directs EPA 
to provide Congress, through OMB, explanations when the Agency decides 
not to use available and applicable voluntary consensus standards.
    In this action, EPA has incorporated voluntary consensus standards 
where feasible (See proposed language for Appendix A to Sec. 52.128, 
I.B(iv)). However, in most cases there are no applicable technical 
standards or field procedures specifically designed for the source 
categories at hand. OMB has reviewed and concurred on the applicable 
technical standards proposed in this revision.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Intergovernmental 
relations, Particulate matter.


[[Page 3267]]


    Dated: January 12, 1999.
Carol M. Browner,
Administrator.

    For the reasons set forth in the preamble, part 52, chapter I, 
title 40 of the Code of Federal Regulations is proposed to be amended 
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart D--Arizona

    2. Section 52.128 is proposed to be amended as follows:
    a. Revise paragraph (b)(16)(i).
    b. Revise paragraph (b)(16)(ii)(A).
    c. Revise paragraph (b)(18).
    d. Add paragraph (d)(1)(i)(D) and remove the period at the end of 
paragraph (d)(1)(i)(C) and replace it with ``; or''.
    e. Add paragraph (d)(2)(iv) and remove the period at the end of 
paragraph (d)(2)(iii) and replace it with ``; or''.
    f. Add paragraph (d)(3)(ii)(E) and remove the period at the end of 
paragraph (d)(3)(ii)(D) and replace it with ``; or''.
    g. Remove paragraph (d)(4) and redesignate paragraph (d)(5) as 
paragraph (d)(4).
    h. Remove paragraph (e) and redesignate paragraph (f) as paragraph 
(e).


Sec. 52.128  Rule for unpaved parking lots, unpaved roads and vacant 
lots.

* * * * *
    (b) * * *
    (16) Stabilized Surface--
    (i) Any unpaved road or unpaved parking lot surface where:
    (A) Any fugitive dust plume emanating from vehicular movement does 
not exceed 20 percent opacity as determined in section I.A of appendix 
A of this section; AND
    (B) Silt content does not exceed six (6) percent for unpaved road 
surfaces or eight (8) percent for unpaved parking lot surfaces as 
determined by the test method in section I.B of appendix A of this 
section.
    (ii) * * *
    (A) A visible crust which is greater than 0.6 centimeters (cm) 
thick and is not easily crumbled between the fingers as determined in 
section II.1(i) of appendix A of this section AND is sufficient as 
determined in section II.1(ii) of appendix A of this section;
* * * * *
    (18) Unpaved Road--Any road, equipment path or driveway used by 
motor vehicles or off-road motor vehicles that is not paved which is 
open to public access and owned/operated by any federal, state, county, 
municipal or other governmental or quasi-governmental agencies or any 
private entity or individual(s).
* * * * *
    (d) * * *
    (1) * * *
    (i) * * *
    (D) Apply and maintain an alternative control measure such that the 
surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
* * * * *
    (2) * * *
    (iv) Apply and maintain an alternative control measure such that 
the surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
    (3) * * *
    (ii) * * *
    (E) Apply and maintain an alternative control measure such that the 
surface is stabilized, provided that the alternative measure is not 
prohibited under paragraph (b)(2) or (b)(4) of this section.
* * * * *
    3. Appendix A to Sec. 52.128 is proposed to be amended as follows:
    a. In section I. by designating the text under Section I as A. and 
adding a heading.
    b. Add section I.B.
    c. Revise the heading of section II.1.
    d. Designate the existing text of II.1 as II.1(i) and add II.1(ii).
    e. Revise section II.4(ii).
    f. Redesignate section II.4(iii) as section II.4(iv).
    g. Redesignate section II.4(iv) as section II.4(v).
    h. Add section II.4(iii).

Appendix A to Sec. 52.128--Test Methods To Determine Whether a 
Surface Is Stabilized

I. Unpaved Roads and Unpaved Parking Lots

A. Opacity Observations

* * * * *

B. Silt Content

    Conduct the following test method to achieve the silt content of 
unpaved road and unpaved parking lot surfaces.
    (i) Collect a sample of loose surface material from an area 30 
cm by 30 cm (1 foot by 1 foot) in size to a depth of approximately 1 
cm using a brush and dustpan or other similar device. Collect the 
sample from a routinely-traveled portion of the surface which 
receives a preponderance of vehicle traffic, i.e. as commonly 
evidenced by tire tracks. Conduct sweeping slowly so that fine 
surface material is not released into the air. Only collect samples 
from surfaces that are not wet or damp due to precipitation or dew.
    (ii) Obtain a shallow, lightweight container and a scale with 
readings in half ounce increments or less. Place the scale on a 
level surface and zero it with the weight of the empty container. 
Transfer the entire sample collected to the container, minimizing 
escape of particles into the air. Weigh the sample and record its 
weight.
    (iii) Obtain and stack a set of sieves with the following 
openings: 4 mm, 2 mm, 1 mm, 0.5 mm, and 0.25 mm. Place the sieves in 
order according to size openings beginning with the largest size 
opening at the top. Place a collector pan underneath the bottom 
(0.25 mm) sieve. Pour the entire sample into the top sieve, 
minimizing escape of particles into the air by positioning the 
sieve/collector pan unit in an enclosed or wind barricaded area. 
Cover the sieve/collector pan unit with a lid. Shake the covered 
sieve/collector pan unit vigorously for a period of at least one (1) 
minute in both the horizontal and vertical planes. Remove the lid 
from the sieve/collector pan unit and disassemble each sieve 
separately beginning with the largest sieve. As each sieve is 
removed, examine it for a complete separation of material in order 
to ensure that all material has been sifted to the finest sieve 
through which it can pass. If not, reassemble and cover the sieve/
collector pan unit and shake it for period of at least one (1) 
minute. After disassembling the sieve/collector pan unit, transfer 
the material which is captured in the collector pan (silt fraction) 
into the lightweight container originally used to collect and weigh 
the sample. Minimize escape of particles into the air when 
transferring the material into the container. Weigh the container 
with the material from the collector pan and record its weight. 
Multiply the resulting weight by 0.38 if the source is an unpaved 
road or by 0.55 if the source is an unpaved parking lot, divide by 
the total sample weight and multiply by 100 to arrive at the percent 
silt content.
    (iv) As an alternative to conducting the procedure described 
above in section I.B.(ii) and section I.B.(iii) of this appendix, 
the sample (collected according to section I.B.(i) of this appendix) 
may be taken to an independent testing laboratory or engineering 
facility for silt content analysis according to the following test 
method from ``Procedures For Laboratory Analysis Of Surface/Bulk 
Dust Loading Samples'', (Fifth Edition, Volume I, Appendix C.2.3 
``Silt Analysis'', 1995), AP-42, Office of Air Quality Planning & 
Standards, U.S. Environmental Protection Agency, Research Triangle 
Park, North Carolina.
    1. Objective--Several open dust emission factors have been found 
to be correlated with the silt content (<200 mesh) of the material 
being disturbed. The basic procedure for silt content determination 
is mechanical, dry sieving. For sources other than paved roads, the 
same sample which was oven-dried to determine moisture content is 
then mechanically sieved.
    2.1  Procedure--Select the appropriate 20-cm (8-in.) diameter, 
5-cm (2-in.) deep sieve sizes.

[[Page 3268]]

    Recommended U. S. Standard Series sizes are \3/8\ in., No. 4, 
No. 40, No. 100, No. 140, No. 200, and a pan. Comparable Tyler 
Series sizes can also be used. The No. 20 and the No. 200 are 
mandatory.
    The others can be varied if the recommended sieves are not 
available, or if buildup on 1 particulate sieve during sieving 
indicates that an intermediate sieve should be inserted.
    2.2  Obtain a mechanical sieving device, such as a vibratory 
shaker or a Roto-Tap  1 without the tapping 
function.
---------------------------------------------------------------------------

    \1\ CFR 60, App. A, Meth. 5, 2.1.2, footnote 2.
---------------------------------------------------------------------------

    2.3  Clean the sieves with compressed air and/or a soft brush. 
Any material lodged in the sieve openings or adhering to the sides 
of the sieve should be removed, without handling the screen roughly, 
if possible.
    2.4  Obtain a scale (capacity of at least 1600 grams [g] or 3.5 
lb) and record make, capacity, smallest division, date of last 
calibration, and accuracy. (See Figure A of this appendix)
    2.5  Weigh the sieves and pan to determine tare weights. Check 
the zero before every weighing. Record the weights.
    2.6  After nesting the sieves in decreasing order of size, and 
with pan at the bottom, dump dried laboratory sample (preferably 
immediately after moisture analysis) into the top sieve. The sample 
should weigh between 400 and 1600 g (0.9 and 
3.5 lb). This amount will vary for finely textured materials, and 
100 to 300 g may be sufficient when 90% of the sample passes a No. 8 
(2.36 mm) sieve. Brush any fine material adhering to the sides of 
the container into the top sieve and cover the top sieve with a 
special lid normally purchased with the pan.
    2.7  Place nested sieves into the mechanical sieving device and 
sieve for 10 minutes (min). Remove pan containing minus No. 200 and 
weigh. Repeat the sieving at 10-min intervals until the difference 
between 2 successive pan sample weighings (with the pan tare weight 
subtracted) is less than 3.0%. Do not sieve longer than 40 min.
    2.8  Weigh each sieve and its contents and record the weight. 
Check the zero before every weighing.
    2.9  Collect the laboratory sample. Place the sample in a 
separate container if further analysis is expected.
    2.10  Calculate the percent of mass less than the 200 mesh 
screen (75 micrometers [m]). This is the silt content.

Figure A. Example Silt Analysis Form

Silt Analysis

Date:------------------------------------------------------------------
By:--------------------------------------------------------------------
Sample No:-------------------------------------------------------------
Sample Weight (after drying)-------------------------------------------
Material:--------------------------------------------------------------
Pan + Sample:----------------------------------------------------------
Pan:-------------------------------------------------------------------
Split Sample Balance:--------------------------------------------------
Dry Sample:------------------------------------------------------------
Make-------------------------------------------------------------------
Capacity:--------------------------------------------------------------
Smallest Division------------------------------------------------------
Final Weight-----------------------------------------------------------

Net Weight <200 Mesh
% Silt = Total Net Weight  x  100 =____%

                                 Sieving
------------------------------------------------------------------------
              Time: Start:                      Weight (pan only)
------------------------------------------------------------------------
Initial (Tare):
10 min:
20 min:
30 min:
40 min:
------------------------------------------------------------------------


 
----------------------------------------------------------------------------------------------------------------
                                                    Final weight (screen
          Screen             Tare weight (screen)        + sample)         Net weight ( sample)         %
----------------------------------------------------------------------------------------------------------------
\3/8\ in..................
4 mesh....................
10 mesh...................
20 mesh...................
40 mesh...................
100 mesh..................
140 mesh..................
200 mesh..................
Pan.......................
----------------------------------------------------------------------------------------------------------------

    (v) The percent silt content for any given unpaved road surface 
or unpaved parking lot surface shall be based on the average of at 
least three (3) samples that are representative of routinely-
traveled portions of the road or parking lot surface. In order to 
simplify the sieve test procedures in section I.B.(ii) and section 
I.B.(iii) of this appendix, the three samples may be combined as 
long as all material is sifted to the finest sieve through which it 
can pass and the combined weight of the samples is calculated and 
recorded accurately.

II. * * *

1. Visible Crust Determination

    (i) Thickness
* * * * *
    (ii) Sufficiency
    (A) Where a visible crust exists, drop a steel ball with a 
diameter of 15.9 millimeters (0.625 inches) and a mass of 16.33 
grams from a distance of 30 centimeters (one foot) directly above 
(at a 90 degree angle perpendicular to) the soil surface. If 
blowsand is present, clear the blowsand from the surfaces on which 
the visible crust test method is conducted. Blowsand is defined as 
thin deposits of loose uncombined grains covering less than 50 
percent of a vacant lot which have not originated from the 
representative vacant lot surface being tested. If material covers a 
visible crust which is not blowsand, apply the test method in 
section II.2 of this appendix to the loose material to determine 
whether the surface is stabilized.
    (B) A sufficient crust is defined under the following 
conditions: once a ball has been dropped according to section 
II.1.(ii)(A) of this appendix, the ball does not sink into the 
surface so that it is partially or fully surrounded by loose grains 
and, upon removing the ball, the surface upon which it fell has not 
been pulverized so that loose grains are visible.
    (C) Conduct three tests, dropping the ball once per test, within 
a survey area the size of one foot by one foot. The survey area 
shall be considered sufficiently crusted if at least two out of 
three tests meet the definition in section II.1.(ii)(B) of this 
appendix. Select at least two other survey areas that represent the 
disturbed surface area and repeat this procedure. Whether a 
sufficient crust covers the disturbed surface area shall be based on 
a determination that all of the survey areas tested are sufficiently 
crusted.
    (D) At any given site, the existence of a sufficient crust 
covering one portion of a disturbed surface may not represent the 
existence or protectiveness of a crust on another disturbed 
surface(s). Repeat the visible crust test as often as necessary on

[[Page 3269]]

each representative disturbed surface area for an accurate 
assessment of all disturbed surfaces at a given site.
* * * * *

4. * * *

    (ii) Count the number of standing vegetative structures within 
the survey area. Count vegetation which grows in clumps as a single 
unit. Where different types of vegetation exists and/or vegetation 
of different height and width exists, separate the vegetative 
structures with similar dimensions into groups. Count the number of 
vegetative structures in each group within the survey area. Select 
an individual structure within each group that represents the 
average height and width of the vegetation in the group. If the 
structure is dense (i.e. when looking at it vertically from base to 
top there is little or zero open air space within its perimeter), 
calculate and record its frontal silhouette area according to 
Equation 6 of this appendix. Also use Equation 6 if the survey area 
is larger than three square feet, estimating the average height and 
width of the vegetation. Otherwise, use the procedure in section 
II.4.(iii) of this appendix to calculate the Frontal Silhouette 
Area. Then calculate the percent cover of standing vegetation 
according to Equations 7, 8 and 9 of this appendix. (Ensure 
consistent units of measurement, e.g. square feet or square inches 
when calculating percent cover.)
    (iii) Vegetative Density Factor. Cut a single, representative 
piece of vegetation (or consolidated vegetative structure) to within 
1 cm of surface soil. Using a white paper grid or transparent grid 
over white paper, lay the vegetation flat on top of the grid (but do 
not apply pressure to flatten the structure). Grid boxes of one inch 
or one-half inch squares are sufficient for most vegetation when 
conducting this procedure. Using a marker or pencil, outline the 
shape of the vegetation along its outer perimeter according to 
Figure B, C or D of this appendix, as appropriate.

    Note: Figure C differs from Figure D primarily in that the width 
of vegetation in Figure C is narrow at its base and gradually 
broadens to its tallest height. In Figure D, the width of the 
vegetation generally becomes narrower from its midpoint to its 
tallest height.) Remove the vegetation and count and record the 
total number of gridline intersections within the outlined area, but 
do not count gridline intersections that connect with the outlined 
shape. There must be at least 10 gridline intersections within the 
outlined area and preferably more than 20, otherwise, use smaller 
grid boxes. Draw small circles (no greater than a \3/32\ inch 
diameter) at each gridline intersection counted within the outlined 
area. Replace the vegetation on the grid within its outlined shape. 
From a distance of approximately two feet directly above the grid, 
observe each circled gridline intersection. Count and record the 
number of circled gridline intersections that are not covered by any 
piece of the vegetation. To calculate percent vegetative density, 
use Equations 10 and 11 of this appendix. If percent vegetative 
density is equal to or greater than 30, use the equation below that 
matches the outline used to trace the vegetation (Figure B, C or D) 
to calculate its Frontal Silhouette Area. If percent vegetative 
density is less than 30, use Equations 12 and 13 of this appendix to 
calculate the Frontal Silhouette Area.

Height  x  Width = Frontal Silhouette Area  Eq. 6
(Frontal Silhouette Area of Individual Vegetative Structure)  x  
Number of Vegetation Per Group = Frontal Silhouette Area of Group  
Eq. 7
Frontal Silhouette Area of Group 1 + Frontal Silhouette Area of 
Group 2 (etc..) = Total Frontal Silhouette Area  Eq. 8
(Total Frontal Silhouette Area/Survey Area)  x  100 = Percent Cover 
of Standing Vegetation  Eq. 9
[(Number of circled gridlines within the outlined area counted that 
are not covered by vegetation/Total number of gridline intersections 
within the outlined area)  x  100] = Percent Open Space  Eq. 10
100-Percent Open Space = Percent Vegetative Density  Eq. 11
Percent Vegetative Density/100 = Vegetative Density  Eq. 12
[GRAPHIC] [TIFF OMITTED] TP21JA99.005


BILLING CODE 6560-50-P

[[Page 3270]]

[GRAPHIC] [TIFF OMITTED] TP21JA99.002


Cylinder:

Frontal Silhouette Area = maximum (max.) height  x  max. width  Eq. 
16
[GRAPHIC] [TIFF OMITTED] TP21JA99.003

Inverted Cone:

Frontal Silhouette Area = max. height  x  \1/2\ max. width  Eq. 17

[[Page 3271]]

[GRAPHIC] [TIFF OMITTED] TP21JA99.004



Upper Sphere:

Frontal Silhouette Area = (3.14  x  max. height  x  \1/2\ max. 
width)/2  Eq. 18

[FR Doc. 99-1124 Filed 1-20-99; 8:45 am]
BILLING CODE 6560-50-C