41326 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Part 52

[FRL–6131–6]

RIN 2060–ZA02

Promulgation of Federal

Implementation Plan for Arizona—

Phoenix PM–10 Moderate Area;

Disapproval of State Implementation

Plan for Arizona—Phoenix PM–10

Moderate Area

AGENCY: Environmental Protection

Agency (EPA).

ACTION: Final rule.

SUMMARY: Under the authority of section

110(c)(1) of the Clean Air Act (CAA or

‘‘the Act’’), EPA is today promulgating

a federal implementation plan (FIP) to

address the moderate area PM–10

requirements for the Phoenix PM–10

nonattainment area. Specifically, for

both the annual and 24-hour PM–10

standards, EPA is promulgating a

demonstration that reasonably available

control measures (RACM) will be

implemented as soon as possible, a

demonstration that it is impracticable

for the area to attain the standards by

the statutory attainment deadline and a

demonstration that reasonable further

progress (RFP) is being met.

As part of the FIP, EPA is

promulgating a fugitive dust rule to

control PM–10 emissions from vacant

lots, unpaved parking lots and unpaved

roads, and is also promulgating an

enforceable commitment to ensure that

RACM for agricultural sources will be

proposed by September 1999, finalized

by April 2000 and implemented by June

2000.

In addition, EPA is today finalizing its

disapproval of the Arizona moderate

area plan’s RACM, RFP and

impracticability, demonstrations

because those demonstrations do not

adequately address the Act’s moderate

area PM–10 requirements.

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.

EFFECTIVE DATES: The FIP and SIP

actions in this document are effective on

September 2, 1998.

ADDRESSES: A copy of the docket no. A–

09–98, containing material relevant to

EPA’s proposed and final actions, is

available for review at: EPA Region 9,

Air Division, 75 Hawthorne Street, San

Francisco, California 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–09–98 is

also available to review at the Arizona

Department of Environmental Quality,

Library, 3033 N. Central Avenue,

Phoenix, Arizona 85012, (602) 207–

2217, and at the EPA Air Docket

Section, Waterside Mall, Room M–1500,

401 M Street, S.W., Washington, D.C.

20460, (202) 260–7549.

FOR FURTHER INFORMATION CONTACT: For

questions and issues regarding the final

measure for agricultural fields and

aprons contact John Ungvarsky (415)

744–1286; for questions and issues

regarding the final rule for unpaved

parking lots, unpaved roads and vacant

lots contact Karen Irwin (415) 744–1903;

and for other general FIP and SIP

questions and issues contact Doris Lo

(415) 744–1287.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary

A. Background

B. Public Involvement in the FIP Process

C. The Final FIP

II. Background

A. SIP/FIP Background

B. Summary of SIP/FIP Proposal

III. Disapproval of Arizona’s Moderate Area

PM–10 Plan

IV. Final FIP

A. RACM/RACT Demonstration

1. RACT and PM–10 Precursors

2. RACM Demonstration

B. FIP Measures

1. Commitment for Agricultural Sector

2. Rule for Unpaved Parking Lots, Unpaved

Roads and Vacant Lots

a. Background

b. Summary of Changes to the Proposed

FIP Rule

c. Public Comments and EPA Responses

C. Impracticability Demonstration

1. Annual Standard

2. 24-hour Standard

D. Reasonable Further Progress

Demonstrations

1. Revised RFP Demonstration

a. Annual Standard

b. 24-hour Standard

i. Gilbert Monitoring Site

ii. West Chandler Monitoring Site

2. Response to Comments on RFP

Demonstrations

E. Indian Reservations

V. Administrative Requirements

A. Executive Order (E.O.) 12866

B. Regulatory Flexibility Act Analysis

1. Regulatory Flexibility Act Requirements

2. RFA Analysis

a. Federal Rule for Unpaved Roads,

Unpaved Parking Lots and Vacant Lots

b. Federal Commitment for Agriculture c.

Certification

C. Unfunded Mandates Reform Act

(UMRA)

D. Paperwork Reduction Act (PRA)

E. Executive Order 13045: Protection of

Children from Environmental Health

Risks and Safety Risks

F. Submission to Congress and the General

Accounting Office

G. Petitions for Judicial Review

I. Executive Summary

A. Background

The Phoenix area violates both the

annual and 24-hour national air quality

standards for particulate matter with

diameters of 10 microns or less (PM–

10). Particulate matter affects the

respiratory system and can cause

damage to lung tissue and premature

death. The elderly, children, and people

with chronic lung disease, influenza, or

asthma are especially sensitive to high

levels of particulate matter. EPA

recently established a new standard for

particulate matter with diameters of 2.5

microns or less and revised the PM–10

standards. However, EPA also retained

the pre-existing PM–10 standards for a

limited amount of time. Today’s action

only addresses those pre-existing PM–

10 standards.

The primary cause of the PM–10

problem in the Phoenix area is dust on

paved roads kicked up by vehicle traffic,

and windblown dust from construction

sites, earth moving operations, unpaved

parking lots and roads, disturbed vacant

lots, agricultural fields and aprons, and

other disturbed areas.

When an area violates an air quality

standard, the Clean Air Act (CAA)

requires that the area be designated as

nonattainment for that pollutant.

Phoenix was originally designated and

classified as a moderate nonattainment

area for particulate matter, and Arizona

was required to develop a plan that put

into place a basic set of control

measures. These measures did not

adequately control the particulate

pollution problem. When the area failed

to attain the standards in 1994 it was

reclassified as a serious nonattainment

area, and the State is now required to

develop a plan with more

comprehensive control measures.

Despite the fact that the State is now

working on its serious area plan, EPA is

under court order, as a result of a

lawsuit by the Arizona Center for Law

in the Public Interest (ACLPI), to

develop a moderate area federal

implementation plan (FIP) for the

Maricopa area. EPA is required to

prepare this FIP because the State does

not have an approved moderate area

plan. Under the court order, EPA was

required to issue the FIP by July 18,

1998.

In its FIP proposal (63 FR 15920;

April 1, 1998), EPA determined that not

all the basic controls on sources

contributing to violations of the

particulate standards were in place.

While the State had implemented a
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41327

number of measures, including controls

on construction and earth moving

operations, there remained a need for

additional emissions reductions. Having

considered its authority and resource

constraints, EPA proposed two

measures in that rulemaking for the

control of dust from unpaved roads,

parking lots, and vacant lots and

agricultural fields and aprons.

Specifically, EPA proposed a fugitive

dust rule and an enforceable

commitment in regulatory form to

implement control measures for

agricultural PM–10 sources by June

2000. These measures will contribute to

the eventual attainment of both the

annual and 24-hour PM–10 standards.

EPA received comments from the public

on the FIP proposal and has made

changes to the proposed FIP rule for

fugitive dust sources that it is finalizing

today.

The State now intends to submit its

serious area particulate plan in

December of 1998. If the plan includes

control measures for the sources

covered by the FIP and those measures

are approved by EPA, the Agency will

be able to withdraw the final FIP

measures. EPA will continue working

with the appropriate State and local

agencies, as well as the agricultural

community and the cities in the

metropolitan area, to replace the FIP

measures with State measures. EPA

believes that clean air is likely to be

achieved faster, and in greater harmony

with local economic and community

goals, if its role as a backstop is

minimized by effective State and local

actions. Because of the willingness of

the State and local communities to

identify and pursue solutions to their air

quality problems, as evidenced by the

Governor’s Air Quality Strategies Task

Force and the recently adopted Air

Quality Measures Bill (SB 1427), EPA

expects successful State and local

action.

B. Public Involvement in the FIP Process

On April 16, 1998, EPA held a

workshop and public hearing on its

proposal in Phoenix. The workshop

provided an opportunity for EPA to

explain to the community why the

Agency is imposing this FIP, what

measures are included in the FIP, and

who will potentially be impacted by the

FIP. The workshop also provided the

community the opportunity to ask

questions of EPA, and to make

suggestions with respect to its proposed

action. Following the workshop, EPA

took formal testimony at a public

hearing on the FIP proposal. In addition

to the hearing testimony, EPA received

18 comment letters on the proposed FIP.

The comments generally fell into two

categories. Environmental and health

organizations supported the dust rule,

but commented that the FIP did not

impose enough PM–10 controls for

other source categories in the Phoenix

PM–10 nonattainment area. On the

other hand, several of the local

jurisdictions and regulatory agencies

commented that the FIP-imposed

controls were too stringent. EPA

evaluated all the comments, did

additional fieldwork and technical

analysis, and revised the FIP

accordingly.

C. The Final FIP

In response to public comments, EPA

revised the fugitive dust rule, but did

not change the enforceable commitment

for agriculture.

Fugitive Dust Rule

Although EPA has approved a

Maricopa County rule (MCESD Rule

310) which requires controls for

unpaved roads, unpaved parking lots

and vacant lots, the County is not

adequately enforcing its rule for these

three sources due to lack of resources.

Consequently, EPA promulgated a FIP

rule for these sources. EPA’s fugitive

dust rule is intended to establish basic

levels of control that are substantially

equivalent to those established by

Maricopa County Rule 310. The primary

difference between the FIP rule and

Rule 310 is the greater specificity and

detail regarding which control measures

are appropriate for which sources. For

each source category, the FIP rule

includes three to four control measure

options and allows alternative control

measures.

In order to effectively implement the

FIP rule, EPA is providing additional

inspection resources to the Maricopa

County Environmental Services

Department (MCESD) through a CAA

section 105 grant. EPA will rely on these

resources to assist the Agency in

verifying compliance with the FIP rule.

In order to remove the FIP requirement,

MCESD will have to submit to EPA a

credible implementation strategy for

Rule 310, including the provision of its

own additional inspection and

enforcement resources that are not

provided under an EPA grant. It is

EPA’s understanding that MCESD is

trying to obtain these additional

resources. EPA will continue working

with the County to assist that effort so

that the FIP rule can eventually be

rescinded.

Until the FIP is rescinded, however,

EPA intends to work cooperatively with

MCESD to inform the regulated

community of the FIP rule’s

requirements. EPA plans to provide

compliance assistance through

informational brochures, toll free

numbers and internet access. These

tools will help EPA disseminate as

much information as possible to the

public. As new information becomes

available, including alternative control

measures that are being developed by

regulated parties to comply with the

rule, EPA will collaboratively work with

these regulated parties to provide

information to the public.

EPA would like to clarify the

Agency’s position with respect to a

major issue that was raised by several

commenters on the proposed fugitive

dust rule. These commenters believe

that the FIP rule requires a more

stringent level of control than Maricopa

County Rule 310 and that, consequently,

EPA is imposing an additional

economic burden on local

municipalities, and others impacted by

the FIP rule. EPA believes that the FIP

rule does not impose any additional

compliance burden beyond that

required by Rule 310. Because EPA will

fully enforce the FIP rule, which has not

occurred under Rule 310, regulated

entities who have not been in

compliance with existing requirements

to date will need to spend the resources

necessary to come into compliance. This

is not an additional economic burden,

but rather one that some members of the

regulated community have deferred.

However, should EPA receive new

information in the future that indicates

that the FIP controls are more stringent

than those required by the Clean Air

Act, the Agency will propose

appropriate revisions to the FIP.

Enforceable Commitment for

Agriculture

As mentioned above, EPA has

approved Maricopa County Rule 310

which requires control of fugitive dust

sources, including agricultural sources.

However, MCESD is not ensuring

adequate enforcement of the rule for

agricultural fields and aprons.

Therefore, EPA is promulgating an

enforceable commitment in regulatory

form for the FIP that requires EPA to

propose controls on agricultural sources

by September 1999 and implement

these controls by June 2000. The

enforceable commitment has not

changed from the April 1, 1998

proposal. In discussions with key

stakeholders, general agreement was

reached that these controls will be in

the form of best management practices.

EPA believes that this approach will

ensure successful dust control in

Maricopa’s unique environment. We

have worked closely with the Phoenix
41328 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

1As a result of the litigation and the

reclassification of the Phoenix area as a serious PM–

10 nonattainment area, both plans were also

required to address the best available control

measure (BACM), RFP and attainment requirements

in the CAA for serious areas.

2Plan for Attainment of the 24-Hour PM–10

Standard, Maricopa County PM–10 Nonattainment

Area, Final. ADEQ, May 1997.

3The Arizona Center for Law In the Public

Interest (ACLPI), representing the plaintiffs in Ober,

in a comment on the FIP proposal, contends that

the proposed FIP does not contain contingency

measures as required by section 172(c)(9) of the

CAA. EPA disagrees. In today’s final FIP, EPA is

fulfilling an obligation under the consent decree in

the district court Ober case that specifically requires

the Agency to promulgate a federal plan for Phoenix

that meets the moderate area RACM requirement in

CAA section 189(a)(1)(C), RFP requirement in

section 172(c)(2) or 189(c)(1), and attainment

requirement in section 189(a)(1)(B) of the Clean Air

Act. See paragraph 6 of the Modified Second

Consent Decree. EPA’s obligation under the Ober

decree does not extend to the section 172(c)(9)

contingency measures. The section 172(c)(9)

contingency measure requirement is a separate and

distinct statutory requirement and is not an integral

part of RFP or attainment demonstrations under

part D of the CAA. See, e.g., 57 FR 13498, 13543

(April 16, 1992) and 61 FR 51599, 51607 (October

6, 1996). See also footnote 1 in EPA’s orginal

proposed approval of the State moderate area PM–

10 plan for the Phoenix area, 59 FR 38402 (July 28,

1994).

farming community to develop this

commitment, and their comments on

the proposal support it.

In order to remove the FIP

requirements, the State will need to

submit and receive approval of a SIP

measure that replaces the enforceable

commitment. In fact, the Arizona

legislature has passed, and Governor

Hull has signed, the legislative language

needed to establish a state process to

develop best management practices for

control of PM–10. EPA expects to

receive this legislative language as a SIP

revision very shortly and will act on it

expeditiously.

Tribal Issues

There are three Indian reservations

located within the Phoenix

nonattainment area. However, since this

FIP is designed to fill a gap that exists

in the State plan which does not apply

to sources within Indian country, EPA

has not included Indian reservations in

this FIP. All three tribes have expressed

an interest in developing air quality

programs. EPA will develop the data, in

cooperation with the tribes, that is

needed to properly assess whether

controls are required to attain the

standards. EPA will ensure that controls

are implemented either through EPAapproved tribal measures or, if

necessary, federal measures.

Conclusion

EPA appreciates the comments that

were made on the proposed FIP and will

continue to work with the community

as the Agency moves forward to

implement the FIP measures. EPA will

also continue to work with the

community on the development of the

State’s serious area plan. EPA is hopeful

that the local planning effort will result

in an approvable SIP that will allow

EPA to withdraw its FIP.

II. Background

A. SIP/FIP Background

Today’s federal implementation plan

(FIP) is the result of over six years of

planning and litigation regarding the

control of PM–10 emissions in the

Phoenix area. On November 15, 1991, as

required by the CAA, the State of

Arizona submitted to EPA a moderate

area PM–10 state implementation plan

(SIP). EPA found that plan to be

incomplete and, as a result, the State

revised and resubmitted it on March 3,

1994. On April 10, 1995, EPA approved

the revised plan which included

reasonably available control measure

(RACM) and reasonable further progress

(RFP) demonstrations, and a

demonstration that it was impracticable

for the Phoenix area to attain the PM–

10 national ambient air quality

standards (NAAQS) by the statutory

deadline of December 31, 1994.

On May 1, 1996, the Arizona Center

for Law in the Public Interest (ACLPI)

filed in the United States Court of

Appeals for the Ninth Circuit a petition

for review of EPA’s April 10, 1995

approval of the State’s PM–10 moderate

area plan. On May 14, 1996, the Ninth

Circuit vacated EPA’s approval of the

plan for failing to adequately address

the moderate area PM–10 requirements.

Ober v. EPA, 84 F.3d 304 (9th Cir. 1996).

Specifically, the Ninth Circuit found

that the State’s plan failed to meet the

CAA’s requirements for attainment, RFP

and RACM for the 24-hour PM–10

standard and that EPA had failed to

provide a sufficient opportunity for

public comment on the RFP and RACM

demonstrations for the annual PM–10

standard.

As a result of the Ninth Circuit’s

ruling, EPA instructed the State of

Arizona to submit by May 9, 1997 a plan

addressing the Act’s moderate area

requirements for the 24-hour PM–10

standard at certain specified monitoring

sites and to submit, by December 10,

1997, a full regional plan addressing

those requirements for both the 24-hour

and annual PM–10 standards.1

Arizona submitted its 24-hour plan 2

(known as the microscale plan) on May

9, 1997. On August 4, 1997, EPA

approved the microscale plan in part

and disapproved it in part. 62 FR 41856.

The State has not yet submitted the full

regional plan, but has indicated that it

intends to do so in December 1998.

Because EPA was unable to fully

approve the State’s microscale plan, the

Agency is required by a U.S. District

Court order to promulgate a FIP by July

18, 1998 that addresses the CAA’s

moderate area requirements for RACM,

RFP and attainment for both the 24-hour

and annual standards. Ober v. Browner,

CIV 94–1318 PHX PGR (D. Ariz.).3

B. Summary of SIP/FIP Proposal

On April 1, 1998, EPA proposed a FIP

for the Phoenix PM–10 nonattainment

area that was published in the Federal

Register at 63 FR 15920. The proposed

FIP included a demonstration that all

RACM are being implemented, a

demonstration that it is impracticable to

attain the PM–10 standards with the

implementation of all RACM and a

demonstration that RFP in emissions

reductions is being made.

As part of its proposed RACM

demonstration, EPA proposed a fugitive

dust rule to control PM–10 emissions

from vacant lots, unpaved parking lots

and unpaved roads, and an enforceable

commitment to ensure that RACM for

agricultural sources will be proposed by

September 1999, finalized by April 2000

and implemented by June 2000. Further

detail on the proposed rule and

commitment is provided in connection

with the discussion of EPA’s final

actions in section IV. below and in the

proposed rulemaking at 63 FR 15920,

15935.

On April 1, 1998, EPA also withdrew

a 1996 proposed action to restore its

approval of portions of the State’s

moderate area SIP for the annual

standard and proposed to disapprove

the RACM and impracticability

demonstrations in Arizona’s moderate

area plan because those demonstrations

do not adequately address the Act’s

moderate area PM–10 requirements.

Further discussion of the SIP actions is

provided in section III. below and in the

proposed rulemaking at 63 FR 15920,

15925.

EPA received 18 public comment

letters from a wide range of parties

including private citizens, state and

local agencies, industry representatives,

and environmentalists. EPA also held a

public hearing on the proposed FIP in

Phoenix at which 7 groups or

individuals testified. Copies of the

comment letters and the transcript of

the public hearing can be found in the

docket for this rulemaking.
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41329

4EPA received one public comment from ACLPI

which supported EPA’s withdrawal of its prior

proposal to restore the approval of the State’s

moderate area SIP as well as the RACM and

impracticability demonstrations therein.

5 In a 1994 rulemaking, EPA established the

Agency’s selection of the sequence of these two

sanctions: the offset sanction under section

179(b)(2) shall apply at 18 months, followed 6

months later by the highway sanction under section

179(b)(1) of the Act. EPA does not choose to deviate

from this presumptive sequence in this instance.

For more details on the timing and implementation

of the sanctions, see 59 FR 39859 (August 4, 1994),

promulgating 40 CFR 52.31, ‘‘Selection of sequence

of mandatory sanctions for findings made pursuant

to section 179 of the Clean Air Act.’’

6See 57 FR 18070, 18072 (Appendix C) (April 28,

1992).

III. Disapproval of Arizona’s Moderate

Area PM–10 Plan

In its proposed action for this

rulemaking, EPA withdrew its earlier

proposal at 61 FR 54972 (October 23,

1996) to restore the Agency’s approval

of Arizona’s moderate area PM–10 plan

for the Phoenix nonattainment area.4 At

the same time, EPA proposed to

disapprove the RACM demonstration

and the demonstration that attainment

by the moderate area attainment

deadline was impracticable in the

State’s moderate area plan. See 63 FR

15920, 15925–15926. EPA is today

taking final action to disapprove that

plan.

The CAA establishes specific

consequences if EPA finds that a state

has failed to meet certain requirements

of the CAA. Of particular relevance here

is CAA section 179(a)(1), the mandatory

sanctions provision. Section 179(a) sets

forth four findings that form the basis

for application of a sanction, including

disapproval by EPA of a State’s

submission based on its failure to meet

one or more required CAA elements.

EPA has issued a regulation, codified at

40 CFR 51.31, interpreting the

application of sanctions under section

179 (a) and (b).

Generally, if EPA has not approved a

revised SIP revision correcting the

deficiency, within 18 months of the

effective date of today’s rulemaking,

pursuant to CAA section 179(a) and 40

CFR 52.31, the offset sanction identified

in CAA section 179(b) will be applied

in the affected area. Similarly, if EPA

has still not approved a SIP revision

correcting the deficiency 6 months after

the offset sanction is imposed, then the

highway funding sanction will apply in

the affected area, in accordance with 40

CFR 52.31.5 In addition, CAA section

110(c)(1) provides that EPA must

promulgate a FIP no later than 2 years

after a finding under section 179(a)

unless EPA takes final action to approve

the revised plan correcting the

deficiency within 2 years of EPA’s

findings.

There are, however, certain

exceptions to the general rule for the

application of sanctions described

above. The reader is referred to 40 CFR

52.31(d) for the circumstances under

which the application of sanctions may

be stayed or deferred.

IV. Final FIP

A. RACM/RACT Demonstration

1. RACT and PM–10 Precursors

In its proposed rulemaking, EPA

determined that the SIP already

included reasonably available control

technology (RACT) for major sources of

PM–10 and that the FIP did not need to

further address this requirement. See 63

FR 15920, 15927. No comments were

received on this determination.

EPA also proposed to find, based on

existing modeling, that major stationary

sources of PM–10 precursors do not

contribute significantly to PM–10 levels

in the Maricopa area which exceed the

PM–10 air quality standards, and

therefore, RACT on these major sources

is not required under CAA section

189(e). See 63 FR 15920, 15928. Under

CAA section 189(e), the control

requirements applicable to major

stationary sources of PM–10 must also

be applied to major stationary sources of

PM–10 precursors, unless EPA

determines such sources do not

contribute significantly to PM–10 levels

in excess of the standards in the area.

EPA received one comment, addressed

below, on this proposed finding.

Comment: ACLPI asserts that EPA’s

proposal to waive the RACT

requirement for major sources of PM–10

precursors on the ground that such

sources do not significantly contribute

to PM–10 levels is flawed because: (1)

it is based on unapproved, draft

modeling; (2) it is based on the

unsupported and unwarranted

assumption that major source

contributions to secondary particulate

levels are proportional to their presence

in the inventory; and (3) it is based on

the use of ‘‘significance’’ levels from the

Act’s new source review program,

which are not automatically

transferrable to determinations under

CAA section 189(e).

Response: EPA used the State’s

modeling as the technical basis for this

FIP. As such, the modeling was subject

to public comment as part of the FIP

proposal and did not require a prior

CAA section 110(k) approval for EPA to

use it.

Given the very small presence of

major stationary sources in the

precursor inventory (less than 7 percent

of the entire precursor inventory is from

major stationary sources), assuming a

linear relationship between major

stationary source emissions and their

impact on ambient secondary

concentrations is reasonable. EPA

estimated that major stationary sources

contribute 0.6 μg/m3 to exceedances of

the 24-hour standard and 0.3 μg/m3 to

exceedances of the annual standard, so

even if major stationary sources

contribute to secondary particulate

formation at 2 to 3 times their presence

in the inventory, they would still be an

insignificant source of PM–10 in the

Maricopa area.

The use of significance levels from the

new source review program to

determine if a source contributes

significantly to PM-10 levels in excess

of the air quality standards in the

Phoenix area is discussed in the next

section.

2. RACM Demonstration

In order to determine which RACM to

include in the FIP, EPA first identified

a list of 99 potential control measures.

See Table 1 in the proposed rulemaking

(63 FR 15920, 15929). This list of

measures was taken from the list of

measures developed for the State’s 1991

moderate area plan and included the

measures found in EPA’s guidance 6 as

well as measures recommended by the

Maricopa air agencies and in public

comments on the State’s moderate area

SIP. Nine additional potential measures

were recommended during the public

comment period on FIP: the California

Air Resources Board’s diesel fuel

standards, a mandatory roadside testing

program for diesels, enhanced diesel

inspection and maintenance (I/M),

accelerated replacement/retrofit of pre1988 heavy duty diesel commercial

vehicles, retrofit existing diesel vehicles

(for example, with catalysts),

California’s off-road vehicle and engine

standards, California’s low emission

vehicle standards, continuing expansion

of the enforcement of Rule 310, and a

smoking vehicle identification and

repair program. See Letter, ACLPI to

EPA, Region 9, May 18, 1998, p. 4 and

Public Hearing to Comment on the

Proposed FIP, Reporter’s Transcript of

Proceedings, p. 7–10 (12:00 p.m.

session), p. 5–9 (7:00 p.m. session). EPA

added these nine additional measures to

its list of 99, for a total of 108 potential

measures.

Before evaluating the measures as

RACM, EPA screened the list to

determine which measures were

applicable to the Phoenix area and for

which EPA had legal authority. EPA

then screened the list to determine
41330 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

7See 57 FR 13498, 13540 (April 16, 1992).

8Seven of the additional measures proposed in

public comment are controls for diesel or gasoline

on-road tailpipe emissions. Because diesel and

gasoline tailpipe emissions are de minimis source

categories for purposes of PM–10 RACM in

Maricopa County, EPA has determined that the

seven measures do not constitute RACM for the

Phoenix area. One measure, California’s non-road

engine standards, would control non-road engine

emissions. As noted in the RACM Technical

Support Document (TSD) for the proposal (p. 8),

EPA promulgated non-road engine standards in

1995 and considers these national standards to be

RACM. Because RACM has already been adopted

for this category, EPA does not need to further

evaluate measures, such as the California standards,

for this category. See 63 FR 15920, 15929. Because

the FIP rule controls the same sources as Rule 310,

it effectively operates to expand enforcement of the

rule.

which measures it has already approved

as State RACM or adopted at the federal

level and considers RACM. Where EPA

had already determined a measure to be

RACM, no further analysis of the

measure was necessary. Finally, the

Agency evaluated the resulting shorter

list of measures based on EPA’s RACM

criteria 7 to identify which measures

constituted RACM for the Phoenix area.

These three criteria are de minimis

source category, technical feasibility

(including when the measure could be

implemented), and cost of

implementation. For any RACM rejected

for reasons of technology, cost, size of

source category or timing of

implementation, the Agency provided a

reasoned justification. In all, eleven

measures addressing fugitive dust from

unpaved roads, unpaved parking lots,

disturbed cleared land, and agriculture

remained after the application of the

RACM criteria.8

A complete description of EPA’s

approach to determining RACM can be

found in the proposed rulemaking at 63

FR 15920, 15928. The results of the

initial RACM evaluation are presented

in Table 3 of the proposed rulemaking.

See 63 FR 15920, 15933. The results of

the final RACM evaluation and a

detailed evaluation of each measure

including the reasoned justification if

the measure was rejected is in the final

RACM TSD.

EPA received several comments on

the RACM demonstration and responds

to the most significant below. EPA has

responded to all comments in the TSD.

Comment: ACLPI comments that the

Center disagrees with EPA’s proposal

for exempting de minimis source

categories from the RACM requirement

of the CAA. ACLPI asserts that there is

no authority in the Act for such an

exemption, and that EPA’s position that

de minimis source categories need only

be controlled to the level necessary to

produce RFP and timely attainment

illegally reads the RACM requirement

out of the Act as to such sources.

Response: The CAA does not define

‘‘reasonably available control measure.’’

Because the statute is silent, EPA has

the discretion to develop a reasonable

interpretation. Chevron U.S.A. Inc. v.

NRDC, 467 U.S. 837, 104 S.Ct. 2778, 81

L.Ed.2d 694 (1984). In 1992 preliminary

guidance (General Preamble), EPA set

forth the criteria for states to apply in

determining RACM and reasonably

available control technology (RACT) in

PM–10 moderate area SIPs. Among

other criteria, if a state could show that

a measure was unreasonable because the

emissions from the affected source

would be insignificant, i.e., de minimis,

such a measure could be excluded from

further consideration. See 57 FR 13498,

13540. Moreover, EPA believes that

determining the reasonableness of a

measure based on the degree to which

the regulated source contributes to the

problem is consistent with the RACM/

RACT requirements of CAA sections

189(a)(1)(C) and 172(c)(1). Additionally,

RACT is generally only required for

major point sources; i.e., sources above

a certain size threshold. See, for

example, section 182(b)(2). See 57 FR

13498, 13541 for discussion of EPA’s

historical definition of RACT.

In developing its federal plan for the

Phoenix area, EPA applied this criterion

by defining a reasonably available

measure, in part, as one that applies to

a source that significantly contributes to

PM–10 exceedances. See 63 FR 15920,

15927. In discussing the de minimis

criterion in its proposed rulemaking,

EPA noted that the regulatory scheme

for particulate matter in subpart 4 of the

CAA establishes two graduated levels of

controls, RACM and BACM, depending

on the severity of the area’s air quality.

See CAA section 189(a) and (b). These

statutory requirements, applicable to

moderate and serious PM–10 areas,

respectively, clearly contemplate that

sources that contribute to a lesser degree

to the particulate matter problem need

not, in the first instance, bear the

burden of emission reductions. Thus, in

determining the initial level of control,

EPA believes that it is appropriate to

focus on the reasonable and practicable

measures for reducing PM–10 emissions

from those sources identified through

air quality modeling as contributing to

a greater degree, i.e., significantly, to

PM–10 exceedances in the Phoenix area.

Alternatively, even absent EPA’s

discretionary authority to develop

reasonable interpretations in the face of

statutory silence, as stated in the

General Preamble, the inherent

authority of administrative agencies to

exempt de minimis situations from a

statutory requirement has been upheld

in contexts where an agency is invoking

a de minimis exemption as ‘‘a tool to be

used in implementing the legislative

design when ‘‘the burdens of regulation

yield a gain of trivial or no value.’’

Alabama Power Co. v. Costle, 636 F.2d

323, 360–61 (D.C. Cir. 1979). See 57 FR

13498, 13540. As noted in EPA’s

response to the comment below, the

provision of RACM for the source

categories for which measures were

rejected because of de minimis

emissions would have little impact on

the nonattainment problem in the

Phoenix area.

Because the Act can reasonably be

interpreted to allow the use of a de

minimis criterion for judging whether a

measure is RACM, EPA does not believe

that its interpretation that de minimis

source categories need only be

controlled to the level necessary to

produce RFP and timely attainment

results in reading the RACM

requirement out of the Act as to such

sources.

Comment: ACLPI further claims that

EPA’s de minimis exemption is contrary

to the Act’s emphasis on timely

attainment and protection of health, and

that control of a source category

contributing de minimis amounts could

make the difference between attainment

and nonattainment. Therefore, ACLPI

asserts that it is irrational for EPA to

assert that such source categories are

invariably de minimis.

Response: For PM–10, EPA has not

determined that a given source’s or

source category’s emissions impact is

invariably de minimis for determining

RACM. What constitutes a de minimis

source category is dependent upon

specific facts of the nonattainment

problem under consideration. In

particular, it depends upon whether

requiring the application of RACM for

such sources or source categories would

contribute significantly to the Act’s

purpose of achieving attainment of the

NAAQS as expeditiously as practicable.

For the Phoenix PM–10

nonattainment problem, the subject of

this FIP, controls on the source

categories that EPA found to be de

minimis would not make the difference

between attainment and nonattainment.

Five Phoenix area monitoring sites with

expected PM–10 exceedances were

evaluated to determine which source

categories were de minimis for the

purpose of the RACM demonstration in

this FIP: four sites for the 24-hour

standard and one site for the annual

standard. In order to be considered a de

minimis source category in the FIP’s

RACM analysis, a source category had to

be de minimis at all five monitoring
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41331

9EPA has already approved the attainment

demonstration for the Salt River monitor. See 62 FR

41856, 41862 (August 4, 1997). This attainment

demonstration showed that controls on the de

minimis source categories would not result in more

expeditious attainment.

sites and de minimis for both the 24-

hour and annual standards. As

illustrated in Table 1, three of the five

evaluated monitoring sites did not have

de minimis sources identified as

contributing anything to the

exceedance. At the two remaining

sites—Greenwood and Salt River—de

minimis source categories contribute

substantially less than 10 percent to the

exceedance and in neither case would

complete elimination of these sources

result in attainment at the site.9 Hence

in Phoenix, the use of a de minimis

source category criterion to judge the

reasonableness of controls has not

excused controls on sources that would

make the difference between attainment

and nonattainment.

TABLE 1.—CONTRIBUTION OF DE MINIMIS SOURCES TO EXCEEDANCES IN

THE PHOENIX METROPOLITAN AREA

Monitor

De Minimis

sources

without

RACM

as percent of

exceedance

De Minimis

sources

without

RACM

as percent of

PM–10

standard

24-Hour Exceedances:

West Chandler ........... 0 0

Gilbert ........................ 0 0

Maryvale .................... 0 0

Salt River ................... 3.9 4.3

Annual Exceedances:

Greenwood ................ 4.7 5.6

Comment: ACLPI claims that EPA’s

choice of 5 μg/m3 and 1 μg/m3 as the

significance thresholds for contributors

to 24-hour and annual PM–10 levels

respectively has no rational basis

whatsoever and that the fact that EPA

uses these thresholds in the new source

review programs does not make them

logical choices as thresholds for an

entirely different purpose.

Response: As stated in the proposal,

EPA is relying on the new source review

permitting program’s significance

thresholds ‘‘as a surrogate for

determining which source categories

require application of RACM’’, and ‘‘not

for determining which source categories

need controls for attainment.’’ 63 FR

15920, 15927. The new source review

program and nonattainment planning

provisions are both elements in the

CAA’s title I provisions to attain and

maintain the health-based air quality

standards. The new source review

program’s significance levels are used to

judge when a source will have a

significant impact on a PM–10

nonattainment area. See 40 CFR

51.165(b). For the purposes of this FIP

only, EPA used the 5 μg/m3 and 1 μg/

m3 significance thresholds for

essentially the same purpose: to judge

whether a source or source category has

a significant impact on the Phoenix PM–

10 nonattainment area.

A significance threshold should be set

at a level that segregates the

insignificant source categories from the

ones that contribute most to a

nonattainment problem. As noted above

in Table 1, in Phoenix, de minimis

sources, i.e., those that contribute less

than 5 μg/m3 to the 24-hour standard

exceedances and 1 μg/m3 to the annual

standard exceedances, account in total

for less than 10 percent of the impact at

any monitor that exceeds either PM–10

standard. Thus, because the selected

thresholds result in the imposition of

controls on the sources that have a

greater emissions impact on the air

quality problem, their application, in

EPA’s view, is most likely to result in

substantial air quality improvements.

There were 12 source categories that

fell beneath these surrogate significance

thresholds and which EPA determined,

therefore, were de minimis in the

proposed FIP’s RACM analysis:

industrial yards, surface mining, other

industrial activities, gasoline-powered

engines, on-road motor vehicles, dieselpowered on-road motor vehicles,

residential wood combustion, other fuel

combustion (e.g., residential space and

water heaters and commercial boilers),

open burning and other area sources,

charbroiling, locomotives, airport

ground support equipment, and major

point sources. Measures for residential

wood combustion, open burning, and

major point sources categories were

excluded from the RACM analysis

because RACM had already been

approved for them. The list of potential

RACM did not include measures for the

other fuel combustion sources or the

charbroiling categories, nor were any

measures for these categories suggested

in the public comments received on the

FIP. See Table 1 in the proposed

rulemaking, 63 FR 15920, 14929. The

industrial yards, surface mining, and

other industrial activities source

categories were found to have an impact

only at the Salt River monitor, a monitor

for which EPA has already approved an

attainment demonstration that showed

controls on these sources would not

result in more expeditious attainment.

See 62 FR 41856, 41862.

Tailpipe emissions from gasolinepowered engines which account for

only 0.3 μg/m 3 impact on the annual

standard exceedance at the Greenwood

monitor are already subject to stringent

controls including the emission

standards under the Federal Motor

Vehicle Control Program, Arizona’s

premier I/M program, and the State’s

Clean Burning Gasoline program. Diesel

powered on-road vehicles including

trucks are also subject to national diesel

fuels standards and tailpipe emission

standards. See 40 CFR 80.29 (diesel fuel

standards) and 40 CFR part 86, subpart

H and 62 FR 54694 (October 21, 1997)

(diesel tailpipe standards).

Finally, it is important to review how

the significance thresholds actually

affected the outcome of the RACM

analysis. EPA used the de minimis

criterion as a justification for excluding

measures for tailpipe emissions from

on-road motor vehicles, locomotives,

airplanes, airport ground equipment,

off-road motorcycles, and heavy-duty

construction equipment. See Table 3 in

the proposed rulemaking, 63 FR 15920,

14933. The two latter categories are very

small contributors to the overall nonroad engine source category. In total,

these categories contributed 1.4 μg/m 3

to the annual standard exceedance at

the Greenwood monitor and nothing to

the 24-hour exceedances.

Comment: The Arizona Department of

Environmental Quality (ADEQ)

comments that the determination of

significant and de minimis sources for

the annual PM–10 standard which was

based upon preliminary modeling

results using Urban Airshed Modeling

(UAM) should be re-evaluated because

the emissions inventory and dispersion

modeling have not been reconciled

against receptor modeling, as

recommended under EPA’s guidance for

PM–10 plans (PM–10 SIP Development

Guideline, EPA–450/2–86–001, June

1986). ADEQ suggests that this should

concern EPA because the inventory

source apportionment differs greatly

from receptor modeling source

apportionment from the 1989–90

Phoenix PM–10 Study (Desert Research

Institute, 1991). ADEQ states that, while

these data are not relatively recent, large

changes in the character of ambient

particulate pollution since the time that

study was conducted would not be

expected and these data have been

corroborated by more recent chemical

analysis of particulate monitor filters

from monitors in the urbanized portion

of the Phoenix metropolitan area. ADEQ

notes that the emission inventory is

dominated by sources of geologic PM,

even for the fine (PM–2.5 and smaller)

particulate. ADEQ states that it rarely
41332 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

finds more than 10 percent geologic

materials in the measured fine PM

fraction, whereas the emissions

inventory estimates that over 70 percent

of the fine PM is geologic. Based on the

filter data, ADEQ concludes that the role

of combustion sources relative to

geologic sources is underestimated in

the inventory, stating that carbon

particles, both primary and secondary,

rival geologic material in terms of PM–

10 mass, but are minor in the PM–10

inventory that EPA is using.

Response: EPA agrees that, ideally,

dispersion and receptor modeling

should be reconciled, using accepted

protocols, such as the one in Protocol

for Reconciling Difference Among

Receptor and Dispersion Models (EPA–

450/4–87–008). However, the

concentrations to be reconciled should

be matched in terms of sampling period;

i.e., 1989/90 data should not be used to

reconcile modeling for 1995. Moreover,

modeling of recent high PM–10 days

would not necessarily be expected to

match those observed in the Desert

Research field study. During that field

study, daily concentrations averaged 4

to 97 μg/m 3, depending on the

monitoring site, with no 24-hour

NAAQS exceedances observed.

Although the data from this field study

were all that were available for the

State’s initial moderate area plan and

were acceptable on that basis, it is not

reasonable to require analysis of recent,

exceedance days to match the earlier

work. Unfortunately, no later receptor

modeling was available for the FIP for

reconciliation. See also the response to

ACLPI’s comment regarding the

differences between the 1989 and 1995

emission inventory in section IV.D.2.

below.

B. FIP Measures

1. Commitment for Agricultural Sector

In its April 1, 1998 proposed

rulemaking, EPA proposed an

enforceable commitment to adopt and

implement RACM as required by CAA

section 189(a)(1)(C) for the agricultural

sector in the Phoenix nonattainment

area. Specifically, the proposed

commitment contained enforceable

milestones for EPA’s proposal (by

September 1999), final adoption (by

April 2000), and implementation (by

June 2000) of RACM for agricultural

fields and aprons. In the proposal, EPA

explained its intention to use a

stakeholder approach for the

development of best management

practices (BMPs) to meet the CAA’s

RACM requirement and provide PM–10

emission reductions from agricultural

sources in the Phoenix area.

EPA is today taking final action to

promulgate an enforceable commitment

in 40 CFR 52.127 to adopt and

implement RACM as required by CAA

section 189(a)(1)(C) for the agricultural

sector. While EPA received a number of

comments on its proposed commitment,

to which it responds below and in the

TSD, the Agency is, in this final rule,

retaining the text of the commitment as

proposed.

Comment: ACLPI and the American

Lung Association of Arizona (ALAA)

claim that a mere commitment to

develop unspecified controls for

agricultural fields and aprons is

inadequate and does not meet the CAA

requirements or EPA guidance for

enforceable measures as expeditiously

as practicable. The commenters contend

that such a commitment offers no

assurance that adequate controls will

ever be adopted.

Response: Because the commenters

provide no citations or analysis, in favor

of a broad claim of inadequacy, EPA is

left to divine the precise nature of their

legal challenge to the provisions for

agriculture in the proposed FIP. To the

extent that the commenters are

suggesting that ‘‘a mere commitment’’ is

not cognizable under the CAA, EPA

notes that the Agency has a long history

of approving enforceable commitments

in SIPs under the statute. Moreover, the

milestones in such commitments have

routinely been deemed to be enforceable

in CAA section 304 citizen suits. For an

extensive discussion of the legal basis

for such approvals under the CAA as

amended in 1990, see 62 FR 1150,

1155–1157 (January 8, 1997).

In its April 1, 1998 Federal Register

notice, EPA proposed a commitment to

adopt and implement RACM for

agricultural fields and aprons by

specified dates that, as finalized today,

will be enforceable in a citizen suit. In

that proposal, EPA explained its

rationale for addressing agricultural

sources of PM–10 emissions. In short,

the Agency believes that, given the

current state of its knowledge of the

local agricultural community and

conditions, the BMP process the Agency

intends to pursue is the approach most

likely to lead to effective controls on

these sources in the shortest possible

time frame. See 63 FR 15920, 15935–

15936.

EPA has issued detailed preliminary

guidance on the appropriate

methodology for determining RACM

under CAA sections 172(c)(1) and

189(a)(1)(C), as well as a list of available

fugitive dust control measures. See 57

FR 13540–13541; 13560-13561 and 57

FR 18071, 18072. EPA followed this

guidance in determining federal RACM

in the proposed FIP. In carrying out its

FIP commitment to propose RACM for

agricultural fields and aprons by no

later than September 1999, EPA will

adhere to the RACM guidance in effect

for these sources at that time. As with

all proposed EPA rulemakings, the

public will have the opportunity to state

its views on the legal adequacy of the

proposed controls. Should EPA fail to

propose RACM for these sources by

September 1999, ACLPI and ALAA may

pursue their remedies under CAA

section 304. Once EPA takes final

adoption action, they can of course

petition for review of that action under

CAA section 307.

Comment: ACLPI argues that since

agricultural control measures have been

adopted in other states, e.g., in

California’s Coachella Valley, or

identified by the Governor’s 1996 Task

Force, there is no excuse for delay.

ACLPI also comments that even if

further delay in development of

agricultural controls were warranted,

EPA cannot justify taking more than a

year to develop proposed rules and that

there is no reason the Agency cannot

adopt enforceable rules within 6

months. ACLPI asserts that 6 months

would allow time for obtaining

stakeholder input without turning rule

development into a protracted exercise.

Response: Prior to the FIP proposal,

EPA evaluated available measures for

agriculture adopted by the South Coast

Air Quality Management District

(SCAQMD): 403—Fugitive Dust; 403.1—

Wind Entrainment of Fugitive Dust; and

1186—PM–10 Emissions from Paved

and Unpaved Roads, and Livestock

Operations. As discussed in the FIP

proposal, EPA determined that there

was insufficient information available to

conclude that implementing the

controls in these rules in Maricopa

County would, taking all relevant

factors into account, be appropriate, i.e.,

reasonable, and thus constitute RACM

for this area. See 63 FR 15920, 15935.

EPA intends to consider whether these

or other measures would be appropriate

for the Phoenix area during the BMP

development process.

ACLPI dismisses EPA’s statements

regarding the Agency’s inability to

ascertain the suitability of the SCAQMD

measures for the Phoenix area by

asserting that the ‘‘techniques for

controlling agricultural emissions are

well known.’’ This assertion ignores the

fact, noted by EPA in its proposed

rulemaking, that PM–10 strategies in an

agricultural context are uniquely based

on local circumstances, and could vary

greatly due to factors such as regional

climate, soil type, growing season, crop

types, water availability, and relation to
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41333

10 It is important to note that the measures

identified by the Governor’s 1996 Task Force were

initially intended to be voluntary and would

require a process virtually identical to that

envisioned by EPA in its FIP in order to be

developed into effective controls. The Task Force

measures, along with any other measures

potentially available for Maricopa County, will be

evaluated as part of the BMP development process.

11 Governor Hull recently signed SB 1427 ‘‘Air

Quality Measures’’ which authorizes a state-led

BMP process. Section 16. Title 49, chapter 3, article

2, of the Arizona Revised Statutes was amended by

adding section 49–457, Agricultural best

management practices committee; members;

powers; permits; definitions. The State has

indicated to EPA that section 49–457 will be

submitted to EPA in the coming months as a

replacement for the portion of the FIP which

addresses agricultural sources.

urban centers. 62 FR 15920, 15935. A

resolution of these uncertainties, in the

context of an assessment of the potential

mix of control measures, is critical to a

determination of whether controls such

as those contained in the SCAQMD

rules are reasonably available for the

Maricopa County nonattainment area

and will contribute to attaining the PM–

10 standards in the area. Such an

assessment is fully consistent with

EPA’s guidance regarding the process

for determining RACM.

As a result, EPA determined that the

goal of attaining the PM–10 standards in

Maricopa County with respect to

agricultural sources would be best

served by engaging all interested

stakeholders in a joint comprehensive

process on the appropriate mix of

agricultural controls to implement in

Maricopa County. EPA believes that this

process, despite the additional time

needed to work through it, will

ultimately result in a best and most costeffective controls on agricultural sources

in the County. EPA has thus committed

in the final FIP to propose RACM for the

agricultural sector by September 1999,

with final adoption in April 2000. Given

the number of potential BMPs, the

variety of crops types, the need for

stakeholder input, and the time

necessary to develop the BMPs into

effective control measures, EPA believes

that the adoption schedule is

expeditious.10

Comment: The American Farm

Bureau Federation (AFBF) contends that

because little data exist for agriculture’s

contribution to PM–10, there is a need

for sound science before regulation and

the California Regional Particulate

Matter Air Quality Study (CRPMAQS)

will provide additional data. AFBF

claims that any agricultural emission

controls are premature and should be

postponed until the CRPMAQS data is

available. The Maricopa County Farm

Bureau (MCFB) also comments that

agricultural controls are premature,

citing University of California and

University of Arizona research

suggesting current PM–10 emission

estimates from agricultural sources are

overstated.

Response: On August 4, 1997, EPA

disapproved portions of the State’s

microscale plan, in part because it

demonstrated, through a scientific

study, that agricultural sources

contribute significantly to exceedances

of the PM–10 air quality standards in

Maricopa County, but did not provide

for the implementation of RACM for

agricultural fields and aprons. 62 FR

41856, 41862. As a result, EPA is

providing for RACM implementation for

these sources.

Moreover, other than vague

statements about lack of data and sound

science, AFBF failed to describe any

specific deficiencies in the scientific

study that resulted in the conclusions in

the microscale plan. Likewise, MCFB

failed to cite any specific research data

that would refute those conclusions.

EPA believes that the microscale plan’s

conclusions were based on sound

science, as demonstrated by an

intensive study throughout 1995 which

included field surveys, aerial

photography, examination of activity

logs, and interviews with source

operators. See Microscale plan,

Appendix A, Chapter 4. The study

resulted in substantially better

emissions inventory data than were

usually available. The study included

extensive monitoring and a thorough

analysis of the area’s PM–10 problem.

The State used locally-developed

emission factors in its modeling.

Overall, the episodes modeled in the

microscale plan are representative of the

conditions under which the

exceedances of the 24-hour PM–10

NAAQS occur. Model performance was

generally good and well within what

can be expected from the type of model

used. See 62 FR 31025, 31031.

EPA will use the CRPMAQS and any

other information appropriate for the

Maricopa area as the data become

available. However, it is important to

note that the PM–10 exceedances in

Maricopa County are typically caused

by wind-blown, primary particulates

(i.e., geologic sources). The PM–10

exceedances in the San Joaquin Valley

(where the CRPMAQS is underway) are

caused by primary and secondary

particulates and typically are not

associated with high wind events. While

the CRPMAQS will yield a tremendous

amount of new information, much of the

information may not be applicable to

Maricopa. For the foregoing reasons,

EPA does not believe that postponing

development of the BMPs pending the

completion of the CRPMAQS would be

appropriate.

Comment: AFBF comments that this

past March, the U.S. Department of

Agriculture-Natural Resources

Conservation Service (USDA-NRCS)

Agricultural Air Quality Task Force

agreed to develop a PM–10

implementation policy that will help

guide states and EPA when dealing with

agriculture and PM–10. Thus, AFBF

believes that any agricultural emission

controls are premature and should be

postponed until a USDA Task Force

policy is available. MCFB and AFBF

believe that if USDA develops a national

policy which outlines voluntary

controls for agricultural PM–10,

enforceable provisions should be

removed from the FIP and SIP. They

state that the final FIP should include

language that will allow for the FIP to

be revised as data and policy become

available.

Response: Regarding the issue of

whether the FIP agricultural provisions

are premature, see EPA’s response to

AFBF’s previous comment. In addition,

EPA does not believe that postponing

development of the BMPs pending the

development of a USDA Task Force

policy would be appropriate. EPA has

worked extensively with MCFB, the

Arizona Farm Bureau Federation and

other stakeholders to craft a workable

strategy for Maricopa County. The

Arizona Federation supported

legislation recently signed by Arizona

Governor Hull for a State-led process for

developing BMPs.11 EPA supports the

position of the farming interests in

Maricopa County to implement the

recently adopted legislation and thereby

maintain local control over the solution.

If EPA adopts a national policy for

PM–10 emissions from agricultural

sources that the State and the Maricopa

County farming community would like

to use, EPA will assess its implications

for the area and work with the

agricultural leaders and the local air

agencies on any appropriate changes to

the current strategy.

Comment: MCFB comments that the

24-hour exceedances attributed to

agricultural sources occurred during a

dust storm and unless BACM are in

place, EPA will not consider natural

occurrences, such as a dust storm, as a

source of PM–10. Because dust storms

will happen whether or not BACM are

in place, MCFB would like this policy

to be changed before any industry is

burdened with control measures.

Response: Contrary to MCFB’s

contention, the exceedances which

implicate agricultural sources did not

occur during dust storms. Rather they
41334 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

12 Memorandum from Mary D. Nichols, EPA, to

EPA Regional Offices, entitled ‘‘Areas Affected by

PM–10 Natural Events,’’ dated May 30, 1996.

13Section 221 of Rule 310 is entitled ‘‘Reasonable

Available Control Measure (RACM)’’ and the term

‘‘RACM’’ is used throughout the rule. EPA has

approved Rule 310 into the SIP as meeting the

enforceability requirements of CAA sections

110(a)(2)(A) and 172(c)(6). See 62 FR 31025, 31032

(June 6, 1997) and 62 FR 41856, 41864. Regardless

of the terminology in Rule 310, as just noted, EPA

has determined that the County’s implementation of

the rule does not meet the RACM implementation

requirement of CAA section 189(a)(1)(B) for

unpaved roads, unpaved parking lots and vacant

lots.

14For example, section 312 of Rule 310 regulates

users of unpaved roads, while EPA’s rule proposed

regulation of only owners and operators; and Rule

310 does not exempt any unpaved roads, while

EPA’s rule included a low ADT exemption.

15For the reasons discussed in this section, EPA

believes that the final FIP rule, with the

modifications made in response to comments,

meets the RACM requirements of the CAA.

16EPA intends to propose new test methods to

replace the opacity (and corresponding opacity

standard) and the visible crust method as proposed

in the FIP and include an additional test method

for standing vegetation. In response to public

comments, EPA conducted technical field work in

Phoenix on the proposed test methods. While they

were the best available methods known to EPA at

the time of proposal, additional analysis has

indicated that other test methods may be more

accurate and comprehensive. EPA also intends to

propose the elimination of the requirement to

submit ACMs to EPA for approval unless the ACM’s

effectiveness cannot be measured by the test

methods or specific language included in the rule.

EPA is also considering whether to propose an

amendment to the FIP rule that would require

RACM for unpaved roads that are neither owned

nor maintained by a public entity.

resulted from normal wind conditions

which routinely occur. A review of the

exceedances and monitoring data used

in support of the State’s microscale plan

indicates that the exceedances were

localized and did not occur at many of

the monitoring sites. If the exceedances

had been caused by a dust storm,

exceedances would be expected

throughout the County.

EPA does have a policy 12 that permits

dust raised by high winds from

anthropogenic sources controlled with

BACM to be treated as due to a natural

event. Key aspects of the policy include

that EPA will not designate an area as

nonattainment when NAAQS violations

are caused by natural events and EPA

would consider redesignating an area to

attainment if it had BACM in place and

the only violations were due to high

wind events. However, and more

importantly, the policy is explicit that

all exceedances, no matter what the

cause, are of concern to public health

and steps need to be taken to reduce

public exposure to unhealthful

particulate levels. Therefore, there is a

need to reduce the level of exceedances

during natural events even if the

exceedances cannot be eliminated;

hence, the requirement for BACM.

Comment: MCFB states that Maricopa

County is the fastest growing county in

the nation and that rapid growth is

forcing land out of agriculture at a rate

of 6,000 acres per year. MCFB urges that

because the growth is pushing

agriculture out of business, agriculture

should be released from further controls

or it will only speed the disappearance

of agriculture from the Phoenix area.

MCFB believes that the only way to

eliminate PM–10 is to regulate farmers

out of existence in Maricopa County.

Response: In the FIP proposal, EPA

acknowledged that agricultural land is

being converted into other uses.

However, even with rapid conversion,

agricultural lands will remain a

significant source of PM–10 for the

foreseeable future. EPA’s purpose here

is to effectively control PM–10, not to

put farmers out of business. Through the

stakeholder process, EPA will work

with the farming community to meet

that goal while ensuring that the BMPs

developed to meet the CAA’s RACM

requirement are economically feasible.

In addition, some cities in Maricopa

County have begun to express interest in

preserving agricultural lands for open

space. This interest may reduce the

amount of land being converted from

agricultural use.

2. Rule for Unpaved Parking Lots,

Unpaved Roads and Vacant Lots

a. Background. In its April 1, 1998

notice, EPA proposed a FIP rule for

Phoenix that required RACM for

unpaved parking lots, unpaved roads

and vacant lots. The reader should

consult that notice for a detailed

discussion of the requirements EPA

proposed for these sources. See 63 FR

15920, 15937.

In the FIP proposal, EPA explained

that MCESD has adopted, and EPA has

approved, MCESD Rule 310 that

requires RACM for fugitive dust sources,

including those regulated in the FIP.

However, because EPA had previously

determined that the County was not

enforcing the rule for these three PM–

10 sources, the Agency disapproved the

State’s RACM demonstration for them.

62 FR 41856, 41862.13 As a result, EPA

is promulgating a federal RACM rule

covering these sources. Because the

deficiency in the State’s RACM

demonstration did not relate to the

substance of MCESD’s fugitive dust rule,

EPA modeled its proposed rule on Rule

310.

The primary difference between the

County rule and EPA’s proposed rule

was that, because EPA’s San Francisco

office would be responsible for its

enforcement, the FIP rule provided

greater specificity and detail regarding

which control measures are appropriate

for which sources. See 63 FR 15920,

15937; 15942-115943. Since, by its

terms, the requirements of Rule 310 are

so broad, the general effect of this

greater specificity and detail was that

EPA’s proposed FIP rule, in its entirety,

while achieving what the Agency

believed to be a RACM level of control,

was somewhat narrower in scope than

the County’s rule as it relates to

unpaved roads, unpaved parking lots

and vacant lots.14

EPA is today promulgating a final FIP

fugitive dust rule at 40 CFR 52.128 that

incorporates a number of changes in

response to public comments. Those

changes, summarized and discussed

below and in the TSD, reflect the same

fundamental philosophy described

above. The net result of the substantive

changes is to provide sources with

greater flexibility than provided in the

FIP proposal.15 For example, the final

FIP rule includes an increase from 0.10

acre to 0.50 acre in the de minimis

disturbed surface area level for vacant

lots; an increase from 150 average daily

trips (ADT) to 250 ADT in the ADT

exemption level for unpaved roads; a

new de minimis use level for unpaved

parking lots; and the elimination of the

dust control plan (DCP) requirement for

weed abatement.

In a separate rulemaking, EPA plans

to propose and take comment on

amendments to some of the alternative

control measure (ACM) and test method

provisions of today’s final rule. While

EPA believes that these changes are

warranted,16 EPA cannot include them

in today’s final action because they are

beyond the scope of the proposed FIP

rule. Because EPA has a court-ordered

deadline of July 18, 1998 to promulgate

the FIP rule, the Agency is taking final

action on its rule without the ACM and

test method changes, but will publish

the proposed amendments shortly.

b. Summary of Changes to the

Proposed FIP Rule. In addition to the

substantive changes to the proposed FIP

rule referenced above that provide

additional flexibility, the final FIP rule

also includes changes that clarify or

revise the RACM implementation

schedules. Other final FIP rule changes

provide minor clarifications of the FIP

rule provisions such as adding language

to clarify test methods, exemptions and

definitions. The substantive changes to

the final FIP rule are summarized below

by source category.

Unpaved Parking Lots and Unpaved

Roads. The final rule:
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41335

17The Maricopa PM–10 nonattainment area is

comprised of the greater Phoenix metropolitan area

in Maricopa County and the Apache Junction area

in Pinal County. The State submitted separate

moderate area PM–10 plans for the Maricopa

County portion and the Pinal County portion of the

nonattainment area. The incompleteness finding

that triggered EPA’s obligation to promulgate this

FIP was made only on the submitted plan for

Maricopa County and thus EPA’s FIP authority only

extends to this part of the nonattainment area. The

Pinal County plan became complete by operation of

law on May 14, 1992. As a result, EPA is clarifying

that this FIP does not cover the Apache Junction

area.

18The fact that MCESD enforces Rule 310 for

these sources on a complaint basis is clear evidence

that they are included within the regulatory scope

of the rule. 19See footnote 13.

• Increases the ADT exemption level

for unpaved roads from 150 ADT to 250

ADT.

• Includes a de minimis use

exemption for unpaved parking lots and

requires RACM only on surfaces where

vehicles park.

• Eliminates the 2-inch requirement

for gravel and relies on the applicable

test methods for compliance.

• Includes organic stabilizers in

addition to chemical stabilizers.

• Eliminates the provision requiring

RACM only where 70 percent of the

unpaved road is located within the

Phoenix nonattainment area and focuses

on the unpaved roads or portion of an

unpaved road located within the

nonattainment area.

• Clarifies that operators of privatelyowned public access unpaved roads are

the parties responsible for compliance

with the RACM requirements.

Vacant Lots. The final rule:

• Eliminates the requirement for dust

control plans in favor of a provision

requiring compliance with three RACM

options.

• Increases the de minimis disturbed

area level from 0.10 acre (proposed rule)

to 0.50 acre.

• Includes a de minimis exemption

(5,000 square feet) for lots disturbed by

motor vehicle trespassing.

• Modifies the time frame for RACM

to be implemented on disturbed

surfaces from eight months to 60 days,

except for the initial eight months

following the effective date of the rule.

• Expands RACM for motor vehicle

disturbances on vacant lots.

• Eliminates the 2-inch requirement

for gravel and relies on the applicable

test methods for compliance.

• Includes an initial eight-month time

frame following the final rule’s effective

date for implementation of RACM for

motor vehicle disturbances and weed

abatement.

• Clarifies the rule’s test methods and

contains language for some test methods

that were previously only referenced in

the proposed rule.

General Changes. The final rule:

• Clarifies the requirements to which

exemptions apply.

• Clarifies that the tribal lands within

the Phoenix PM–10 nonattainment area

are not covered by the provisions of the

FIP rule.

• Clarifies that Apache Junction is not

covered by the provisions of the FIP

rule.17

c. Public Comments and EPA

Responses. Implementation Costs.

Comment: The Maricopa Department

of Transportation (MCDOT) and the

Arizona Chamber of Commerce (ACOC)

assert that EPA’s interpretation of

Maricopa County Rule 310 as currently

requiring suppression of dust on all

unpaved public access roads is

incorrect. MCDOT claims that in the

development of the rule, MCDOT,

MCESD and other stakeholders agreed

to commit to a dust reduction program.

MCDOT states that the rule called for

use of RACM on unpaved roads in

Section 312 with reference to the list of

measures in Section 221. MCDOT

further states that, while not explicitly

stated in the rule, EPA and MCESD have

always interpreted RACM to include a

financial and cost effectiveness test and

that MCESD has in practice accepted the

SIP commitments for dust suppression

and the five-year work plan for capital

projects as what was reasonably

available. MCDOT says that its

commitment was to stabilize 25 miles of

roadway per year. MCESD also makes

similar comments regarding its

acceptance of the five-year work plans

for capital projects as satisfying the

RACM requirement.

Response: EPA notes that MCDOT

concedes, by its references to sections

312 and 221 of Rule 310, that the

regulatory scope of these sections of

Rule 310 encompasses the same

universe of sources and measures as the

proposed FIP rule. Thus, the issue is

whether any acceptance by MCESD of

MCDOT’s SIP commitment to stabilize

25 miles of roadway per year constitutes

compliance with the rule. In EPA’s final

action on the State’s microscale plan,

EPA determined that the MCESD’s

implementation of Rule 310 (i.e.,

enforcement on a complaint basis for

vacant lots, unpaved parking lots and

unpaved roads 18) is inadequate and

consequently disapproved the RACM

demonstration in that plan for these

sources. 62 FR 41856, 41865. EPA

received no public comments which

disagreed with this finding. Moreover,

MCESD has never incorporated a 25

mile stabilization limit into Rule 310.

Nor has EPA made a determination or

approved into the Phoenix PM–10 SIP

MCDOT’s 25 mile stabilization

commitment as representing a RACM

level of control. Therefore, as a legal

matter, such an understanding between

MCESD and MCDOT does not establish

MCDOT’s commitment as meeting the

RACM requirements of the CAA.19

As stated above, EPA modeled its FIP

rule on Rule 310, but provided greater

detail and specificity which had the

effect of narrowing the scope of Rule

310. As explained in more detail below,

EPA believes, based on the information

currently available to the Agency, that

the requirements of the final FIP rule

meet the economic feasibility criterion

in the Agency’s guidance and represent

RACM for unpaved roads.

Comment: MCDOT and the City of

Mesa claim that EPA did not provide

any analysis as to what methods or

criteria were used to identify RACM and

that there is no cost-benefit analysis

provided to demonstrate the reasonable

availability and effectiveness of the

proposed measures. The City of Mesa

asserts that, as EPA stated in the

proposed rulemaking, any measures that

are determined to be de minimis,

technologically infeasible or

unreasonably costly should be removed

from the list of RACM. This commenter

concludes that EPA did not conduct this

analysis as part of the proposed FIP.

Response: In section IV.B. of its

proposed rulemaking, EPA set forth the

criteria that the Agency must apply in

determining what measures constitute

RACM. In general, EPA excludes

measures it determines to be

unreasonably costly, technologically

infeasible or that apply to sources of

PM–10 that are de minimis. 63 FR

15920, 15926. In section V of the FIP

proposal, EPA provided a detailed

description of its approach for

determining which RACM to include in

the proposed FIP. 63 FR 15920, 15927–

34. For the purposes of the RACM

analysis, public sector sources, like

EPA, should evaluate the criterion

relating to the cost of control measure

implementation by considering the

reasonableness of potential RACM based

on the financial and resource

capabilities of the governmental entity

responsible for implementing such

measures. The FIP RACM analysis

involved a list of 99 potential RACM

which were evaluated against 2 sets of

criteria: (1) to determine if a measure

was appropriate for federal

implementation; and (2) to determine if

a measure was RACM. The latter set of

criteria include economic feasibility.
41336 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

20For this reason, EPA disagrees with MCDOT’s

claim that compliance with the FIP rule implicates

the cost-benefit analysis requirements of the

Unfunded Mandates Reform Act. Nor does the FIP

rule constitute a major federal action under the

National Environmental Policy Act (NEPA) as the

commenter suggests. EPA actions under the CAA

are expressly exempt from that statute. 15 U.S.C.

§ 793(c)(1).

21See sections 5.0, ‘‘Emissions Reductions,’’ and

6.0, ‘‘Cost Estimates’’ of the TSD for the Phoenix

FIP Rule for Unpaved Parking Lots, Unpaved Roads

and Vacant Lots.

22MCDOT elaborates on this point by claiming

that long term maintenance data indicate that by

paving these roads, life cycle maintenance costs

will increase by a factor of five. MCDOT estimates

that chemical stabilization will triple the

maintenance cost of these roadways.

EPA did not provide a cost-benefit

analysis for the proposed FIP measures

because, as discussed in the proposed

FIP’s Regulatory Flexibility Analysis, all

of the requirements of the FIP’s fugitive

dust rule are already required under the

County’s Rule 310. See 63 FR 15920,

15942. In fact, EPA believes, as stated

previously, that the scope of the FIP rule

as proposed (and as modified in this

final action) is narrower than that of

Rule 310. Hence the costs of compliance

with the FIP rule should, to the extent

that there is any cost differential, be less

than those for Rule 310.20 See 63 FR

15920, 15943–15944 and section

VII.B.2. below for detailed discussions

of this issue.

Nevertheless, EPA did include

estimates of control effectiveness and

unit costs in the TSD for the FIP rule.21

As discussed in the TSD, the control

effectiveness estimates were based on

available data, which was limited. Thus

only relatively crude estimates were

developed for the emissions reductions

associated with the FIP rule (or

implementation of Rule 310). The unit

costs are based on information found in

documents prepared by or referenced by

the Maricopa Association of

Governments. The costs associated with

the FIP rule and their relationship to the

RACM determination are discussed

further in response to the following

comment.

Comment: MCDOT comments that if

Maricopa County were required to pave

all public access unpaved roads within

its jurisdiction, as described by the

proposed rule, it would require an

expenditure greater than $100 million,

to as much as $300 million, or

approximately 5–10 years of the

County’s total capital improvements

budget for transportation projects.

Furthermore, MCDOT asserts that

additional paving of parking lots and

compliance by cities and towns within

the County could, in aggregate, be

nearly one billion dollars. MCDOT also

claims that there is a substantial

maintenance expense in the future for

all roads paved or stabilized, which will

create an additional tax burden.22

Response: The final FIP rule does not

require the County to pave all of its

unpaved roads. The FIP rule requires

RACM for unpaved roads with greater

than 250 ADT (increased from 150 ADT

in the proposed FIP rule). Compliance

options include methods of stabilization

that are less costly than paving.

As discussed above and in the

proposed FIP’s Regulatory Flexibility

Analysis, the FIP rule does not impose

any additional compliance burden

beyond that required by Rule 310. Thus,

even without the FIP rule, EPA believes

that EPA, a citizen, the State and the

County could enforce under Rule 310

control measures that are more stringent

than those required under the FIP rule.

Because EPA had to develop the FIP

rule within the court-ordered schedule,

EPA was limited in the cost data

available to the Agency for the

economic feasibility analysis prong of

the RACM criteria. See EPA’s response

to the previous comment.

Unfortunately, while commenters on the

proposed FIP rule provided conclusions

as to what they deemed to be

unreasonable compliance costs, they

supplied no supporting data. Therefore,

EPA was unable to use this information

to refine its determination of the RACM

level of control.

Comment: The City of Mesa and

MCDOT maintain that local

governments should have the autonomy

to target unpaved roads that are

determined through local study and

evaluation to significantly contribute to

local or regional PM–10 levels and

develop schedules for paving or

stabilizing those roads with the greatest

potential to decrease PM–10 emissions.

Response: In meeting the RACM

requirements of the CAA, states are free

to select the mechanisms they deem to

be the most appropriate. Such decisions

routinely involve evaluations of the

concerns of local governments. While

EPA has not approved Rule 310 as

meeting the Act’s RACM requirements

for the unpaved road, unpaved parking

lot and vacant lot source categories,

clearly that rule was intended to

provide a County-wide RACM

regulatory scheme. If MCESD and the

State believe that the rule can be

modified to address the concerns raised

by the City of Mesa, Maricopa County or

other local jurisdictions, it is free to do

so and EPA will determine whether the

rule as modified represents RACM and

can replace the FIP rule. In making this

determination, EPA would evaluate

information submitted by MCESD in the

staff report accompanying the rule

justifying why the rule as modified

represents RACM.

In developing the FIP rule, EPA was

constrained by a number of factors that

necessitated a single approach to

implementing RACM for the entire

Phoenix nonattainment area. For

example, EPA’s San Francisco office

must be able to enforce the rule

throughout the nonattainment area and

inform regulated parties of the rule’s

requirements. Resources for public

outreach would be inadequate should

EPA need to administer RACM

differently from one jurisdiction to

another. Moreover, even if EPA could

administer a rule that specifies a

different RACM level of control for the

numerous jurisdictions within the

Phoenix nonattainment area, EPA lacks

the detailed information it would need

to do so. Furthermore, as noted above,

such information has not been

forthcoming in responses to the FIP

proposal.

Comment: MCDOT, ADEQ and the

Arizona Chamber of Commerce all

comment on the issue of legal

responsibility for compliance with the

proposed FIP rule’s requirements for

unpaved roads. The Chamber claims

that the definition in § 52.128(b)(17) of

‘‘unpaved road’’ as ‘‘those * * * owned

by any federal, state, county, municipal

or other governmental or quasigovernmental agencies’ will cause

prohibitively expensive disputes over

ownership between private and public

entities and, due to its vagueness, could

include more than 100,000 roads in the

County. The Chamber also comments

that local governments do not have the

financial resources to decide ownership

and to implement RACM. MCDOT notes

that there is no definition of

‘‘ownership’’ and that in some contexts

the proposed rule refers to ‘‘owner/

operator’’ and in others, strict legal

ownership. In this connection, MCDOT

states that ninety percent of the

unpaved, public access roads it

maintains in the nonattainment area are

not in public ownership. ADEQ makes

a similar point and believes that the

FIP’s requirements should apply only to

publicly-owned roads.

Response: EPA’s intent in proposing

the requirements for unpaved roads was

to ensure that responsible entities apply

RACM to control these fugitive dust

sources. As stated in the proposed

rulemaking, EPA intended to

accomplish this goal by making the

requirements of the FIP rule essentially

mirror those of MCESD’s Rule 310.

Because Section 312 of Rule 310 is very

broadly drafted, EPA attempted in its
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41337

23EPA routinely requires that those responsible

for operation and maintenance of a source comply

with emission or performance standards established

under the CAA. See CAA section 302(k) and (l).

proposal to narrow those responsible for

compliance to owners or operators of

the pollution sources. In order to rectify

the confusion perceived by the

commenters, EPA has amended the final

rule to add the word ‘‘maintains’’ in the

definition of ‘‘owner/operator’’ in

§ 52.128(b)(10) and to add the words ‘‘or

operated’’ in the definition of ‘‘unpaved

road’’ in § 52.128(b)(17).

EPA does not believe that the purpose

of the FIP’s unpaved road requirements

is served by limiting them to those

sources that are publicly owned,

particularly in view of the statistics

provided by MCDOT and ADEQ.

Therefore, EPA has also removed the

word ‘‘public’’ from the definition of

‘‘unpaved road’’ in § 52.128(b)(17) and,

consequently, from the RACM

requirements for unpaved roads in

§ 52.128(d)(2). Thus the final rule

applies to unpaved roads that are open

to public access, but are privately or

publicly owned. These changes are

intended to clarify that both owners,

and operators, including those who

conduct roadway maintenance, are

legally responsible for complying with

the RACM requirements of

§ 52.128(d)(2).23

In response to comments regarding

the vast number of roads implicated by

the proposed RACM requirements, and

the concomitant compliance costs, EPA

has changed the ADT threshold in

§ 52.128(d)(2) from 150 to 250 and

limited the sources to which that

section’s requirements apply to those

portions of an unpaved road located

within the Phoenix PM–10

nonattainment area.

Comment: MCESD comments that a

0.10 acre threshold is appropriate at

which to expect the application of

controls. However, MCESD believes that

enforcement on vacant lots should be

reactive (i.e. complaint driven) for sites

less than a threshold of 10 to 50 acres

and proactive on larger sites. However,

weed abatement operations that are

permitted will be inspected under Rule

310. The inability to know when a

vacant lot has been disturbed

significantly reduces the costeffectiveness of a proactive enforcement

program for vacant lots. The amount of

time spent checking undisturbed vacant

lots adds little value to efforts to reduce

particulate pollution. In addition,

MCESD recommends that EPA refine

what level of enforcement and/or

implementation represents RACM and

which represents BACM. MCESD cites

as an example that their contacts with

Coachella Valley area cities referenced

in EPA’s proposal and the TSD

established that their vacant lot

provisions are enforced on a complaintonly basis.

Response: In its proposed action on

the microscale plan, EPA proposed to

find that the plan did not assure

implementation of either RACM or

BACM as required by CAA sections

189(a)(1)(C) and 189(b)(1)(B) and to

disapprove the RACM/BACM

demonstrations for the unpaved parking

lots, unpaved roads, and vacant land

source categories. This proposed

disapproval was based on the County’s

enforcement of Rule 310 for these

source categories on a complaint-basis

only. See 62 FR 31025, 31034–31035.

MCESD did not make the comments it

now advances in connection with EPA’s

proposed action on the microscale plan.

On August 4, 1997, EPA took final

action to disapprove the microscale plan

provisions for implementing RACM and

BACM for these sources. 62 FR 41856,

41862.

While EPA considered dust control

rules for other areas, RACM and BACM

determinations are made on a case by

case basis. See e.g., 57 FR 13498, 13540,

13561; and 59 FR 41998, 42010 (August

16, 1994). Therefore, the South Coast

Air Quality Management District’s

approach to dust control in Coachella

Valley is not determinative of what

constitutes the implementation of

RACM or BACM for the Phoenix

nonattainment area. As demonstrated in

EPA’s action on the microscale plan,

implementation of Rule 310’s vacant lot

provisions on a complaint basis is not

sufficient to prevent these sources from

contributing substantially to

exceedances of the PM–10 NAAQS in

the Phoenix area. See 62 FR 31025,

31031. Furthermore, RACM and BACM

are levels of emission reduction control.

See 59 FR 41998, 42010. In contrast, the

resources allocated for, and the method

and frequency of, enforcement are the

means of ensuring that such emission

reductions occur, but are not themselves

control levels.

The provisions of Rule 310 require

that RACM, as specified in the rule, be

implemented for the unpaved parking

lots, unpaved roads and vacant land

source categories. Having adopted such

a rule, the County has notified the

affected parties that they must comply

with the rule’s requirements and must

ensure that it has the resources and a

program for ensuring that compliance

occurs. See CAA section 110(a)(2).

Moreover, since the County has

purported to define what constitutes

RACM by the terms of its rule, it cannot

then fail to ensure that those measures

are comprehensively enforced and still

meet the requirement to implement

RACM in CAA section 189(a)(1)(C). If

MCESD believes that Rule 310 as

adopted represents a level of control for

certain sources that is beyond RACM or

BACM, it is free to modify the rule and

submit it to EPA with the appropriate

justification. EPA will then evaluate the

submittal for compliance with the

CAA’s RACM/BACM requirements.

Comment: ACOC comments that the

vacant lot ‘‘Disturbed Surfaces’’

provision of the proposed FIP rule

would impose a huge economic burden

on homebuilders and private

landowners due to the fact that any

amount of disturbed surface area left

vacant for more than fifteen days is

subject to the rule. Also, the average

private citizen would likely be unaware

of this requirement.

Response: Since there is a de minimis

vacant lot size, it is not true that any

amount of disturbed area is subject to

the rule. In the final rule, EPA has

increased the de minimis threshold

from 0.10 to 0.50 acre of disturbed

surface for stabilization of disturbed

surfaces. In any case, the rule does not

pose a huge economic burden on

homebuilders; homebuilders need to

receive a permit under Maricopa County

Rules 200 and 310 for earth-moving

operations over 0.1 acres, and are

therefore not regulated under the FIP

rule. However, should homeowners

prepare vacant property for construction

by scraping and leave the surface

disturbed for over 15 days prior to

construction and permit applicability,

they are subject to the FIP rule. EPA

based the fifteen-day time period on

language in MCESD’s Rule 310 and

believes it is appropriate as the

disturbed vacant lot will be a continual

dust source until re-stabilized. EPA

plans to provide outreach assistance to

vacant lot owners within the first eight

months following the effective date of

the final rule prior to the required

RACM implementation deadline in

order to increase awareness of the FIP

rule and its requirements.

FIP Rule Requirements. De Minimis

Levels.

Comment: Several commenters state

that the requirement in the proposed

FIP rule to pave all public roads with

150 ADT is unreasonable. Commenters

believe that the 150 ADT threshold is

arbitrary, includes too many roads and

is economically burdensome.

Response: EPA believes that a higher

ADT threshold is warranted and

represents a RACM level of control.

Therefore, in the final FIP rule, EPA has

increased the ADT threshold from 150
41338 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

to 250. This higher ADT threshold will

relieve some of the cost burden on

public entities, while targeting the roads

that cause the most PM–10 emissions.

The final rule, with the 250 ADT

threshold, will control dust on roads

which receive two vehicles every five

minutes, on average, throughout

primary driving hours in a given day

rather than one vehicle every five

minutes. EPA, through a contractor, will

by the end of 1998 acquire more data on

the sources subject to the FIP rule,

including unpaved roads and their ADT.

Should EPA determine in the future,

based on additional information, that

the final FIP rule requirements do not

represent a RACM level of control for

the Phoenix area, the Agency will

propose appropriate revisions to the

FIP.

Comment: The Grand Canyon Council

of the Boy Scouts of America comments

that the FIP rule should provide a de

minimis use level below which

requirements are not triggered. The

Council claims that the proposed FIP’s

unpaved parking lot provision does not

allow reduced compliance for lots that

receive relatively little heavy use during

the year (but are used more than 35 days

a year). The Council suggests a de

minimis level of ingress by fewer than

10 or 25 vehicles per day.

Response: In the final rule, EPA

addresses the Council’s concern by

establishing an exempted use level for

unpaved parking lots of 10 vehicles a

day or less. Furthermore, since there are

a number of unpaved parking lots

significantly larger than 5,000 square

feet where parking occurs only in a few

localized areas, in the final rule, the

owner/operator is only required to

implement RACM on the portion of a lot

(as opposed to the entire lot) on which

vehicles park. Notwithstanding regular

use of an unpaved parking lot by 10 or

fewer vehicles, the rule offers flexibility

for lots used no more than 35 days a

year to require RACM controls only if

over 100 vehicles park on the lot and

only for the duration that the vehicles

are parked.

Comment: MCESD comments that the

0.10 acre threshold for vacant lots is an

appropriate threshold at which to

expect application of controls, but that

it is not reasonable to enforce all vacant

lots at this level, except for weed

abatement operations. Several other

commenters suggest that a de minimis

level of 0.10 acre for vacant lots is too

small. Commenters also state that the

regulatory burden on small residential

property owners would be too high and

that disturbed static lots do not

contribute significantly to PM–10

compared to disturbed sites with active

earth-moving operations. Commenters

suggest that the de minimis level be

increased to one or five acres.

Response: In the final rule, EPA has

increased the RACM implementation de

minimis threshold for vacant lot

requirements concerning weed

abatement and disturbed surface from

0.10 acre to 0.50 acre. The final rule’s

de minimis threshold of 0.50 acre is

responsive to commenter’s concerns to

focus the FIP rule on larger disturbed

areas; however, EPA does not believe a

de minimis level greater than 0.50 acres

is warranted given MCESD’s belief that

weed abatement disturbing 0.1 acres

merits control. Since the majority of

vacant lot disturbances are caused by

weed abatement and an uncontrolled

weed abated lot would be covered by

the requirements for disturbed surfaces,

EPA believes there is a need for

consistency between the weed

abatement requirement and the

disturbed surfaces requirement. Thus,

EPA believes that a 0.50 acre de

minimis level is appropriate.

EPA does not believe that the

regulatory burden of the FIP rule will be

high on small residential property

owners as the majority of residential

property owners have homes on their

property. The FIP rule does not apply

unless the property is vacant and

disturbed. Moreover, the FIP rule only

applies where a vacant property’s

disturbed surface area is greater than the

exemption levels. Where the FIP rule

does apply, property owners have a

number of RACM from which to choose,

including lower cost alternatives such

as re-vegetation and watering. In some

cases, vacant lots naturally re-stabilize

with rainfall to form a crust or they

contain sufficient amounts of aggregate

materials or vegetation such that the

standards set forth in the FIP rule are

met. For these reasons, EPA believes the

commenters have over-estimated the

regulatory impact of the FIP rule on

vacant lot owners. Finally, as discussed

in EPA’s responses to comments

regarding the cost impacts of the FIP

rule, because all of the RACM discussed

above and found in the FIP rule are

already required by Maricopa County’s

Rule 310, the final FIP rule does not

impose any additional regulatory

burden beyond Rule 310.

Compliance Deadlines. Comment: The

City of Phoenix comments that the final

rule should move the compliance

deadline for disturbed surfaces on

vacant lots from eight months after the

effective date of the rule to June 10,

2000. The City claims this is needed in

order to ensure that property owners

become aware of the rule and to

implement dust control measures.

Response: EPA believes an eightmonth period of time is sufficient to

conduct public outreach to vacant lot

owners regarding FIP rule requirements

to stabilize property or erect barriers.

EPA plans to provide outreach

assistance to vacant lot owners within

the first eight months following the

effective date of the final rule prior to

the required RACM implementation

deadline in order to increase awareness

of the rule and its requirements. The

only reason the RACM deadline for

public unpaved roads is June 10, 2000

is due to EPA’s recognition that public

entities require additional time to

budget funds to implement RACM. EPA

believes that the majority of vacant lots

with disturbed surfaces can be

stabilized (unless further disturbed) by

applying water or re-vegetating, thus, a

long time-frame for implementing

RACM is unwarranted. Notwithstanding

the initial eight-month time frame for

RACM implementation, the final rule

requires that RACM be implemented

within two months following a

disturbance.

Comment: MCDOT and MCESD

comment that the June 10, 2000

deadline for RACM to be implemented

on roads with 150 ADT or more is not

feasible due to the large amounts of

material and/or chemicals needed and

the time needed to complete roadway

design, right-of-way acquisition and

construction. They state that no other

attainment area has been required to

establish a deadline for completion of

stabilization of unpaved surfaces.

MCESD and ADEQ suggest that a more

appropriate and realistic compliance

target should be an established schedule

that extends beyond June 2000 for

treating public unpaved roads using

ADT to establish priorities.

Response: Since EPA has increased

the ADT threshold to 250 in the final

rule, there will be fewer roads which

require controls under the FIP rule by

June 2000. The June 10, 2000 deadline

has not been established by EPA

arbitrarily. As discussed in the proposed

rulemaking, the deadline for RACM

implementation after the statutory

deadline of December 10, 1993 is as

soon as practicable. 63 FR 15920, 15926.

EPA does not believe it achieves the

purposes of the CAA to allow longdelayed RACM implementation to

extend beyond June 10, 2000 the

statutory deadline for the

implementation of BACM.

Comment: MCESD, ADEQ and the

City of Mesa comment that the proposed

FIP rule’s requirement that a dust

control plan (DCP) for weed abatement

be submitted 60 days in advance is

impractical, given that there is a fire
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41339

endangerment concern between the time

weed abatement public notices are

issued and a 60-day lead time to submit

a DCP to EPA.

Response: In the final rule, EPA has

eliminated the requirement that DCPs

for weed abatement be submitted to EPA

for approval. Instead, the final rule

establishes RACM requirements for

conducting weed abatement on vacant

lots. The RACM are those dust control

measures that EPA would have expected

to see in a DCP. The RACM are written

broadly enough to allow responsible

parties flexibility in what measures they

use to control dust, provided that the

surface is stabilized immediately

following weed abatement to the

standards set forth in the rule.

Alternative Control Measures (ACMs)

Comment: The City of Mesa

comments that the provisions in the

proposed FIP rule for ACMs are unduly

burdensome (in that they must be

submitted to EPA for approval). Rather,

the City believes that if an ACM renders

the disturbed surface area stabilized

without any ancillary adverse impact, it

should be encouraged.

Response: EPA agrees with this

comment and, in a proposed

amendment to the final FIP rule, the

Agency intends to propose that ACMs

be listed among other RACM in each

provision to which they apply. EPA

intends to propose that as long as the

ACM meets the test method’s criteria for

stabilization and does not involve use of

a prohibited material, prior EPA

approval would not be required. Thus,

the only ACM that would be submitted

to EPA would be one that does not

involve stabilizing an unpaved surface.

Vacant Lot RACM. Comment: The

City of Phoenix comments that EPA

should allow alternatives for controlling

dust from vacant lots where vehicles

have caused the disturbed surface in

addition to posting signs or barriers. The

City claims that these controls are

required regardless of the severity of the

disturbance or implementation of other

dust control measures, such as gravel.

Response: In the final FIP rule, EPA

adds gravel and chemical/organic

stabilizers to the list of RACM in the

‘‘Motor Vehicle Disturbances’’

provision. Therefore, a vacant lot owner

may comply with both the ‘‘Disturbed

Surfaces’’ and ‘‘Motor Vehicle

Disturbances’’ requirements by applying

one control measure. Applying gravel or

stabilizers are the only RACM specified

in the rule modification since other

control measures listed under the

‘‘Disturbed Surfaces’’ requirement do

not ensure dust control should further

vehicle trespass occur.

Comment: Several commenters

question the technical justification for a

2-inch gravel requirement, suggesting

that two inches of gravel may not be

necessary in all cases to control

particulate matter sufficiently.

Response: EPA has eliminated

reference in the FIP rule to 2 inches of

gravel. Since the final rule requires that

gravel be applied and maintained to a

sufficient extent necessary to result in a

stabilized surface, the test method will

be the sole indicator of whether a source

is sufficiently graveled.

Test Methods. Comment: MCESD and

the City of Mesa comment that the

proposed visible crust test method for

vacant lots would not be appropriate

since local native soil crusts may

crumble easily and measure less than

0.6 centimeters in thickness, yet still

form a protective surface. ACOC and the

Salt River Project (SRP) also question

the scientific substantiality of the

proposed visible crust test method.

Response: In response to comments

on the FIP proposal, EPA recently

conducted the proposed test methods on

sources in the Phoenix non-attainment

area. As a result of the findings, in a

forthcoming proposed amendment to

the final FIP rule, EPA will propose a

new test method for visible crusts that

involves dropping a small steel ball

from a height of one foot and checking

for pulverization of the surface. EPA

believes that this new method allows a

higher degree of replicability than the

existing visible crust test method and is

a better indicator of whether the crust is

sufficiently protective given variations

in soils.

Comment: Several commenters

mention that the requirement in the

proposed FIP rule that the visible

opacity of vehicles be tested at a specific

speed on unpaved roads and unpaved

parking lots is impractical and may be

unsafe/illegal.

Response: EPA has eliminated the

speed limit requirement in the final

rule. In a forthcoming proposed

amendment to the final FIP rule, EPA

will propose a new test method for

unpaved roads and unpaved parking

lots that involves collecting a surface

sample as opposed to conducting a

visible opacity test at a certain vehicle

speed.

Comment: Several commenters

suggest that the proposed test methods

are too complex to be understood and

utilized by property owners who must

comply with the rule.

Response: EPA has eliminated the

speed limit requirements from the test

method in the final rule. In its

forthcoming proposed amendment to

the final FIP rule, EPA will propose to

eliminate the opacity test method for

visible emissions from unpaved roads

and unpaved parking lots. The opacity

test method requires opacity readings to

be taken by persons certified in visible

emissions training. EPA agrees that this

test method is too complex for most

property owners to attempt. Regarding

the remaining test methods in the final

rule, EPA believes much of the

perceived complexity is a result of

technical language which is necessary to

ensure the test methods are enforceable.

A certain minimum amount of

complexity is necessary to ensure that

the test methods can be repeated by

more than one individual consistently

and accurately, as well as to ensure that

they do not result in over-controlling

sources. EPA plans to provide outreach

assistance to property owners which

will explain the test methods in

layman’s terms and provide information

on the commercially available resources

needed to conduct them.

Enforcement of FIP Rule. Comment:

ACLPI states that while it supports

EPA’s proposal to provide more

enforcement resources for Rule 310, the

staff provided will still be grossly

inadequate. ACLPI notes that EPA does

not explain why just two additional

inspectors will be adequate. ACLPI

states that the Governor’s Air Quality

Strategies Task Force in 1998

preliminarily recommended that the

County add 9 new positions for Rule

310 enforcement and that, to comply

with the RACM mandate, Maricopa

County must have the same or better

enforcement resources than other air

districts which have enforcement staffs

of such size (or larger). ACLPI also

claims that EPA’s proposal also fails to

provide the legal resources necessary to

enforce against violators detected by the

inspectors and believes that the FIP

should require the County (or EPA) to

have a full time attorney to conduct

enforcement cases under Rule 310.

While welcoming EPA’s proposal to

provide additional enforcement

resources, ACLPI urges that the Agency

take steps to ensure that such action

does not encourage continuing and

repeated avoidance by the County of its

obligation to provide these enforcement

resources. ACLPI asserts that one

appropriate step would be for EPA to

impose mandatory or discretionary

sanctions on the County for its failure to

adequately fund Rule 310 enforcement

and suggests that if this or other steps

are not taken, local and state

governments will underfund the

programs and wait for EPA to impose a

FIP that includes federal enforcement

dollars.
41340 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

24That said, EPA agrees that the resources

devoted by the County to compliance with Rule 310

are inadequate with respect to unpermitted sources

and made such a finding in its action on the State’s

microscale plan. 62 FR 41856, 41860. In a March

10, 1998 letter to Al Brown, Director, MCESD, EPA

stated that to replace the FIP rule, MCESD must

submit, as a SIP revision, a credible Rule 310

enforcement strategy that demonstrates that the

County has adequate resources of its own to ensure

that Rule 310 is fully implemented for all fugitive

dust sources. In this regard, EPA supports the

additional resource levels recommended by the

Governor’s Task Force and understands that

MCESD is in the process of trying to obtain them

for the purpose of fully implementing Rule 310.

25The statistics ACLPI cites on the enforcement

resources of other air districts represent the total

number of inspectors for each of these districts to

conduct all air quality inspections for all pollutant

sources. Therefore, these staffing levels cannot be

used as evidence that MCESD underfunds its

fugitive dust program.

26The program is discussed further in the FIP

proposal at 63 FR 15920, 15938–15939.

27Nevertheless, these two inspectors will also

have the opportunity to identify and report Rule

310 violations. Thus they will be able to provide

some incidental assistance to MCESD’s Rule 310

compliance efforts.

28Under CAA section 189(c)(1), the moderate area

attainment deadline was December 31, 1994. The

Phoenix nonattainment area is now classified as

serious. As a result, for the purposes of this

moderate area FIP and the State’s serious area SIP,

the attainment deadline is December 31, 2001. CAA

section 189(c)(2).

Response: EPA would like to clarify at

the outset that the discussion in the

proposed rulemaking to which ACLPI

refers addressed the Agency’s

compliance approach for the proposed

FIP rule, and not Rule 310. Thus, to the

extent that ACLPI’s comments are

directed to the inadequacy of Maricopa

County’s program for Rule 310

enforcement, they are not germane to

this rulemaking.24 In particular, ACLPI’s

remarks regarding inspection and

enforcement resource levels for Rule

310 are entirely inapplicable. The

statistics ACLPI cites from the

Governor’s Task Force Report relate to

resources for the entire universe of

sources, both permitted and

unpermitted, regulated under Rule 310.

The scope of the FIP rule, however, is

considerably narrower than that of Rule

310 in that it only addresses vacant lots,

unpaved parking lots, and unpaved

roads, all fugitive dust sources not

permitted under Rule 310.25

To the extent that ACLPI’s judgments

may call into question the adequacy of

EPA’s enforcement of its own rule, EPA

would like to clarify its FIP compliance

program in two respects.26 First, in

implementing the FIP rule, EPA is

constrained by the remote location of its

Regional Office in San Francisco.

Because of that constraint, EPA believes

that its compliance program for the FIP

rule will benefit substantially by some

kind of local presence. Therefore, EPA

will be funding two inspectors to be

provided to MCESD for fiscal year 1999

(October 1, 1998 through September 30,

1999). The primary responsibility of

these inspectors will be to ensure

compliance with the FIP rule.27 If the

FIP rule remains in place after

September 1999, continuation of these

inspector positions will depend on

whether additional funding can be

secured by EPA.

Second, as discussed in the proposed

rulemaking, in addition to the two

inspectors assigned to MCESD, the

Agency will have at its disposal legal

and technical personnel from its San

Francisco office to ensure compliance

with the FIP rule by conducting

periodic joint inspections with MCESD

and undertaking enforcement actions.

Finally, EPA is somewhat perplexed

by ACLPI’s suggestion that, in the

absence of federal CAA sanctions, local

and state governments will underfund

their Rule 310 enforcement program and

wait for EPA to impose a FIP with

federal enforcement dollars. As just

explained, EPA is not in the FIP

providing either funding or positions for

the benefit of MCESD. Moreover, it has

been the Agency’s experience that the

specter of an active federal presence in

local affairs acts as a powerful

motivator, a view that ACLPI itself has

historically advanced. Indeed, the

recent adoption of State legislation

regulating PM–10 emissions from

agricultural activities is evidence of

such an effect.

C. Impracticability Demonstration

The CAA requires moderate PM–10

nonattainment areas to demonstrate

attainment of the PM–10 annual and 24-

hour standards, or to show that

attainment by the statutory deadline is

impracticable. See section 189(a)(1)(B).

For this FIP, EPA has demonstrated that

existing State controls, together with the

RACM being promulgated by EPA, are

not sufficient for attainment of either

the 24-hour or the annual PM–10

standard by December 31, 2001.28

1. Annual Standard

EPA based its annual standard

attainment analysis on air quality

modeling for the 1995 year performed

by the Maricopa Association of

Governments for Phoenix serious area

PM–10 plan that is currently under

development. See 63 FR 15920, 15939.

As can be seen in Table 2, even

assuming 100 percent control for

sources subject to the FIP rule and the

commitment for the agricultural sector

(an unrealistic level of control; actual

control levels will be less), simulated

concentrations are still over the annual

standard of 50 ‘‘μg/m3. Thus, pursuant

to CAA section 189(a)(1)(B), EPA is

finding that attainment of the annual

PM–10 standard by December 31, 2001

is impracticable with the

implementation of RACM.

TABLE 2.—ANNUAL STANDARD IMPRACTICABILITY DEMONSTRATION

Source category

Concentration

after SIP controls μg/m3

Maximum

possible

control (percent)

Concentration

after FIP controls μg/m3

Paved road dust ............................................................................................................................... 20. .................... 20.0

Unpaved road dust ........................................................................................................................... 2.9 100 0.0

Gasoline and Diesel vehicle exhaust ............................................................................................... 1.2 .................... 1.2

Agricultural dust ................................................................................................................................ 0.2 100 0.0

Other area sources .......................................................................................................................... 1.4 .................... 1.4

Residential wood combustion .......................................................................................................... 0.4 .................... 0.4

Construction/earth moving ............................................................................................................... 5.4 .................... 5.4

Construction equipment, locomotives, other non-road engines ...................................................... 1.4 .................... 1.4

Major point sources .......................................................................................................................... 0.2 .................... 0.2

Windblown dust ................................................................................................................................ 0.4 100 0.0

Anthropogenic Total ......................................................................................................................... 33.5 .................... 30.0

Background ...................................................................................................................................... 22 .................... 22

Total .......................................................................................................................................... 55.5 .................... 52.0
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41341

2. 24-hour Standard

EPA based its 24-hour standard

attainment analysis on air quality

modeling of exceedances at four

monitoring sites that was performed by

ADEQ for the microscale plan. The four

monitoring sites are: (1) Salt River, in an

industrial area; (2) Gilbert, affected by

agricultural and unpaved parking lot

fugitive dust emissions; (3) Maryvale,

with disturbed cleared areas nearby due

to construction of a park; and (4) West

Chandler, near a highway construction

project. These sites were selected to

represent a variety of conditions within

the Maricopa nonattainment area. See

63 FR 15920, 15939.

The microscale plan demonstrated

attainment at the Salt River and

Maryvale sites, and EPA approved the

attainment demonstrations at these sites

at the time it took final action on the

microscale plan. 62 FR 41856, 41862.

The microscale plan did not

demonstrate attainment at the West

Chandler and Gilbert sites. These sites

are addressed here.

The FIP rule requires RACM for

unpaved roads, vacant lots, and

unpaved parking lots. These sources in

total contribute 25 percent of the

emissions to the exceedance at the

Gilbert site and just 1 percent of the

emissions to the exceedance at the West

Chandler site. The FIP rule has a

substantial impact for the Gilbert site,

reducing ambient concentrations from

213 to 176 ‘‘μg/m3 but much less effect

at West Chandler, reducing

concentrations from 332 to just 316 ‘‘μg/

m3. See Table 3. Because the FIP rule

does not result in attainment at either

site, EPA is finding that attainment of

the 24-hour standard is impracticable

with the implementation of RACM.

As can be seen from Table 3,

attainment at both sites will require

substantial reductions from agricultural

sources in addition to reductions from

unpaved roads, unpaved parking lots,

and vacant lots. While reductions from

agricultural sources are expected

through the implementation of BMPs by

2001, EPA is unable to quantify the

impact of these BMPs at this time

because they have not yet been

developed. Therefore it is not possible

to determine an expected level of

control. Once the BMPs have been

defined, EPA will be better able to

estimate reductions from agricultural

sources and will revisit this

impracticability demonstration for the

24-hour standard and modify the

demonstrations as necessary.

TABLE 3—IMPRACTICABILITY DEMONSTRATION FOR THE 24-HOUR PM–10 STANDARD

Source category

Concentration after SIP controls μg/m3 FIP control

(percent)

Concentration after FIP controls μg/m3

Chandler Gilbert Chandler Gilbert

Agricultural fields .............................................................................. 194.7 ...................... .................... 194.7

Agricultural aprons ............................................................................ 21.7 55.6 .................... 21.7 55.6

Road construction ............................................................................. 6.9 ...................... .................... 6.9

Unpaved roads ................................................................................. 0.5 0.5 64 0.2 0.2

Paved Roads .................................................................................... 0.2 1.6 .................... 0.2 1.6

Unpaved parking lots ........................................................................ ...................... 51.3 56 ...................... 22.6

Vacant lots ........................................................................................ 28.1 14.5 56 12.4 6.4

Anthropogenic Total .......................................................................... 252.1 123.4 .................... 236.1 86.3

Background ....................................................................................... 80 90 .................... 80 90

Total ........................................................................................... 332.1 213.4 .................... 316.1 176.3

See section IV.D. below for a

discussion of the estimated emission

reductions from the FIP control

measures.

EPA received a number of comments

on the proposed impracticability

demonstrations. The most significant

comments have been addressed below

and all comments have been fully

addressed in the Response to Comments

TSD.

Comment: ACLPI comments that

EPA’s impracticability demonstration is

flawed because it does not include all

RACM and uses an unapproved state

model. ACLPI asserts that EPA’s failure

to include so called ‘‘de minimis’’

measures in the FIP, as well as the other

measures the Agency has excluded from

the FIP, could very well make the

difference between the showing of

impracticability and a showing of

attainment. ACLPI notes that under the

analysis in Table 5 of the proposed

rulemaking, the FIP measures could

reduce annual PM–10 levels to 52 μg/

m3—only 2 μg/m3 over the standard and

yet EPA’s ‘‘de minimis’’ policy allows

the Agency to avoid adopting any

measures that produce less than 1 μg/m3

in improvement and thus, an additional

package of ‘‘de minimis’’ measures

could well make the difference between

attainment and nonattainment. Based on

the data in Table 2 of the proposed

rulemaking, ACLPI asserts that,

combined, the ‘‘de minimis’’ sources in

that table would reduce PM–10 by 4.0

μg/m3 on an annual basis—more than

enough to produce attainment based on

the data in Table 5 of the Proposed

rulemaking. The Center concludes that

far from showing impracticability,

EPA’s analysis shows that timely

attainment is practicable with the

adoption of additional measures that are

already identified and for which there is

no reasoned justification to reject.

Response: EPA believes that ACLPI’s

comment addresses only the

impracticability demonstration for the

annual standard and is responding to it

on that basis. As noted above, EPA used

the State’s modeling as the technical

basis for this FIP. As such, the modeling

was subject to public comment as part

of the FIP proposal and did not require

a prior CAA section 110(k) approval for

EPA to use it. EPA also demonstrated

that it has included all RACM available

to it in the impracticability

demonstration. See section IV.A.

The projected 52 μg/m 3 concentration

in Table 5 of the proposed rulemaking

assumes complete elimination of

emissions from unpaved roads,

agricultural dust, and windblown

dust—an unrealistic level of control. See

63 FR 15920, 15939. There is currently

insufficient information to accurately

calculate regional reductions from the

FIP measure for unpaved parking lots,

vacant lots, and the commitment for

agricultural controls. By showing that

attainment would still not result even

with 100 percent control on these

sources, EPA was able to find that

attainment of the annual standard is

impracticable with the implementation

of RACM. However, because it was

derived from an assumption of 100
41342 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

29The total sum of the impact of the de minimis

source categories listed on Table 2 of the Proposed

rulemaking is 4.0 μg/m 3; however, in this FIP both

agricultural dust and windblown dust are

considered significant sources because they are

significant sources for the 24-hour standard. As

result the total impact of de minimis sources at the

Greenwood monitor is only 3.4 μg/m 3.

30This conclusion is supported by noting that the

estimated reductions from applying the FIP rule to

one vacant lot for one day at the Chandler

monitoring site is 3.5 metric tons per windy day,

4 percent of the total annual reductions needed to

show an incremental reduction from 1998 to 1999.

percent control, the projected 52 μg/m 3

annual level is too optimistic and the

actual concentration after

implementation of the FIP RACM will

be higher.

The total impact of all de minimis

source categories combined is 3.4 μg/

m 3, or less than 10 percent of the

exceedance of the annual PM–10

standard at the Greenwood monitor.29

Attainment at the Greenwood monitor

would require elimination of more than

half the emissions from these sources in

addition to eliminating all emissions

from the sources subject to the FIP

measures. These de minimis sources

include on-road motor vehicles (already

subject to tailpipe standards, I/M, and

clean fuel requirements), residential

wood combustion (already controlled at

RACM levels), all other combustion

sources, and major point sources

(already subject to RACT). No measures

exist that could reduce emissions from

these sources by more than half by the

end of 2001, short of banning or

substantially curtailing their operations;

neither option would constitute a

reasonable level of control. A more

practicable approach to attaining the

standard at Greenwood is to a obtain the

needed emission reductions from the

source categories that contribute

significantly to the nonattainment

problem at the Greenwood monitor,

source categories such as unpaved road

dust and paved road dust. EPA is

promulgating a rule in this FIP to reduce

emissions substantially from unpaved

roads and EPA evaluated a large number

of measures to reduce emissions from

paved roads (including many

transportation control measures) and

found none that were RACM for the

Agency.

D. Reasonable Further Progress

Demonstrations

As discussed in the proposal, EPA

interprets the RFP requirement for areas

demonstrating impracticability as being

met by showing that the implementation

of all RACM has resulted in incremental

emission reductions below preimplementation levels. See 63 FR

15920, 15927.

RFP is demonstrated separately for

the annual and 24-hour standards

because in the Phoenix area the mix of

sources contributing to the annual

standard exceedances differs from that

contributing to the 24-hour

exceedances. In addition, since PM-10

exceedances in the Phoenix area are

related almost entirely to primarilyemitted PM–10, only emissions of

primarily-emitted PM–10 are evaluated

for RFP.

EPA has revised the annual standard

RFP demonstration from the proposal to

reflect the changes to the FIP fugitive

dust rule. Although EPA does not

believe that annual incremental

reductions are required to be shown for

moderate PM–10 nonattainment areas

demonstrating impracticability, EPA has

also revised the RFP tables (Tables 7, 8,

and 9) from the proposal to show that

the FIP does, in fact, result in annual

incremental reductions. See section

IV.D.1. below.

EPA received a number of comments

on its interpretation of the RFP

requirement for areas demonstrating

impracticability as well as on the

specifics of the RFP demonstration. EPA

responds to the most significant

comments in section IV.D.2. below and

to all comments received in the

response to comments TSD found in the

docket for this rulemaking.

1. Revised RFP Demonstrations

a. Annual Standard. EPA has revised

the annual standard RFP demonstration

to account for the increased ADT

threshold for controls on unpaved roads

in the FIP fugitive dust rule. Revisions

to the FIP rule’s provisions for vacant

lots or unpaved parking lots did not

affect the annual standard RFP

demonstration because no reductions

were assumed from these sources in the

proposed demonstration. The final

annual standard RFP demonstration

showing incremental reductions

between 1998 and 2001 is presented in

Table 4.

Emission levels for 1998, 1999, 2000,

and 2001 were calculated by growing

emissions from the emission inventory

base year of 1994 and the modeling year

of 1995 based on growth factors

provided by MAG and by incorporating

reductions from approved State RACM

and BACM controls. Emissions levels

for 2000 and 2001 also reflect the

estimated emission reductions from the

FIP rule for unpaved roads. The

estimated effectiveness of controls on

unpaved roads, 80 percent, was based

on the research done for the microscale

plan on the effectiveness of controls for

unpaved parking (see Table 4–1 in the

final microscale plan) and assumes a

rule effectiveness of 80 percent per

EPA’s guidance (57 FR 13503). EPA has

not changed these estimated control and

rule effectiveness percentages in this

final demonstration; however, the

Agency estimates that the increase in

the ADT applicability threshold in the

FIP rule will reduce the total unpaved

road VMT impacted by the rule from 90

percent to 50 percent.

The annual standard RFP

demonstration did not include emission

reductions from the implementation of

the FIP rule for unpaved parking lots

and vacant lots. Although emission

reductions are expected from these

sources starting in 1999, there currently

is insufficient information on the

number of unpaved parking lots and

vacant lots that will be subject to the FIP

to estimate an emission reduction.

Information from the surveys EPA will

perform after promulgation of the rule

will help in quantifying emission

reductions from these sources. In

addition, while reductions from

agricultural sources are also expected

starting in 2000, no emission reductions

were assumed in the RFP demonstration

for agricultural sources because the

ultimate RACM have not been defined

and therefore the expected level of

control cannot be determined. Because

the reductions expected from vacant

lots, unpaved parking lots, and

agricultural sources cannot at this time

be quantified, the showing that the FIP

will result annual incremental

reductions is necessarily qualitative.

As can be seen in Table 4, in order to

show annual reductions from 1998 to

1999, emission reductions of more than

87 mtpy would need to result from the

implementation of the FIP fugitive dust

on vacant lots and unpaved parking lots.

The total regional inventory for unpaved

parking lots is currently unknown. The

regional inventory for vacant lots,

however, is estimated to be 2020 mtpy

in 1999. See RFP TSD. The FIP rule will

need to reduce emissions in this

category by a little more than 4 percent

in order to demonstrate annual

incremental reductions. Because

application of dust control measures to

a disturbed surface is expected to

reduce fugitive dust from that surface by

56 percent (see 63 FR 15920, 15941),

EPA is confident that the rule will

achieve at least a 4 percent overall

reduction in regional fugitive dust

emissions from vacant lots sufficient to

show reductions in total regional PM–10

emissions from 1998 to 1999. 30

As can be also be seen in Table 4, in

order to show annual reductions from

2000 to 2001, emission reductions of

more than 239 mtpy would need to
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41343

31While there is no change in total emissions

from 1999 to 2000, EPA believes that annual

incremental reductions are still shown because of the large reduction occurring in the early years

between 1998 and 1999.

result from the implementation of the

BMPs on agricultural sources. The

projected regional inventory for

agricultural sources is 6,972 mtpy in

2001. See RFP TSD. The FIP rule will

need to reduce emissions in this

category by slightly more than 3 percent

in order to demonstrate annual

incremental reductions between 2000

and 2001. Again, EPA has every

confidence that such minimal

reductions can be achieved.

TABLE 4.—RFP DEMONSTRATION FOR

THE ANNUAL STANDARD

Year Total PM–10 emissions metric

tons/year

1998 ..... 61,017.

1999 ..... 61,104—reductions from vacant

lots and unpaved parking lots.

2000 ..... 57,607—reductions from vacant

lots and unpaved parking lots.

2001 ..... 57,846—reductions from vacant

lots, unpaved parking lots, agricultural sources.

b. 24-hour Standard. For the 24-hour

standard, EPA evaluated RFP only for

the Gilbert and West Chandler sites,

having already approved the RFP

demonstrations at the Maryvale and Salt

River sites as part of its action on the

microscale plan. 62 FR 41856, 41862.

Changes to the FIP fugitive dust rule

do not affect the emission reductions

assumed in the proposed RFP

demonstrations for the 24-hour standard

because the rule will continue to apply

in the same manner and to the same

extent as was assumed in the proposal.

In other words, the changes to the FIP

rule do not affect its application to the

sources surrounding the Gilbert and

West Chandler sites.

As with the annual standard

demonstration, 1998 emission levels

were adjusted to reflect implementation

of the improved controls on

construction sources and 2001

emissions levels to reflect the estimated

emission reductions from the proposed

FIP rule for unpaved roads, unpaved

parking lots, and vacant lots. Emission

reductions estimates are again based on

the research done for the microscale

plan and assume a rule effectiveness of

80 percent per EPA’s guidance. For

unpaved roads, a control effectiveness

of 80 percent is assumed. For vacant lots

and unpaved parking lots, a control

effectiveness of 70 percent is assumed.

As with the annual standard, no

emission reductions were assumed for

agricultural sources. A more detailed

analysis of the RFP demonstrations for

the Gilbert and West Chandler monitors

can be found in the RFP TSD.

i. Gilbert Monitoring Site. The 24-hour

exceedances at the Gilbert monitor are

impacted by emissions from agricultural

aprons, disturbed cleared lands (i.e.,

vacant lots), unpaved parking lots, and

paved roads. 62 FR 31025, 31031. As

can be seen from Table 5, the emission

reductions from the FIP rule and

commitment for unpaved parking lots

and vacant lots and agricultural sources

are sufficient to assure incremental

emission reductions between 1998 and

2001 and annual incremental

reductions 31 in the interim years. EPA,

therefore, finds that the FIP assures RFP

for the 24-hour standard at the Gilbert

monitor.

TABLE 5.—RFP DEMONSTRATION FOR THE 24-HOUR STANDARD—GILBERT MONITORING SITE

Source categories FIP control (%) year

Emissions(kg/day)

1998 1999 2000 2001

Agriculture aprons ................................... 0 (2001) ..................... 165 165 165 165 (-reductions from BMPs).

Vacant lots .............................................. 0.56 (1999) ................ 76 33 33 33.

Unpaved parking lots .............................. 0.56 (1999) ................ 190 84 84 84.

Paved roads ............................................ 0 ................................ 5 5 5 5.

Total ................................................. .................................... 436 287 287 287 (-reductions from BMPs).

ii. West Chandler Monitoring Site.

The 24-hour exceedances at the West

Chandler monitor are impacted by

emissions from agricultural fields,

agricultural aprons, road construction,

disturbed cleared lands (i.e., vacant

lots), unpaved roads, and paved roads.

62 FR 31025, 31032. As can be seen

from Table 6, the emission reductions

from the FIP rule for unpaved roads and

vacant lots and and the commitment for

controls on agricultural sources are

sufficient to assure incremental

emission reductions between 1998 and

2001 and annual incremental reductions

in the interim years; therefore, EPA

finds that the FIP assures RFP for the

24-hour standard at the West Chandler

monitor.

TABLE 6.—RFP DEMONSTRATION FOR THE 24-HOUR STANDARD—WEST CHANDLER MONITORING SITE

Source category FIP control (%) Year

Emissions (kg/day)

1998 1999 2000 2001

Agriculture .......................................... 0 (2001) ..................... 19378 19378 19378 19378 (-reductions from BMPs).

Vacant lots .......................................... 0.56 (1999) ................ 6188 2723 2723 2723.

Road Construction .............................. 0 ................................ 440 440 440 440.

Agricultural apron ............................... 0 (2001) ..................... 1954 1954 1954 1954 (-reductions from BMPs).

Unpaved road ..................................... 0.64 (2000) ................ 49 49 18 18.

Paved roads ....................................... 0 ................................ 37 37 37 37.

Total ............................................ .................................... 28046 24581 24550 24550 (-reductions from BMPs).
41344 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

32This requirement for reductions on a ‘‘straightline rate’’ has never been absolute. EPA has stated

that it would accept less than a straight-line rate if

the State could show that a lag was necessary to

accommodate the time required for compliance. See

43 FR 21675 and 44 FR 20372, 20377 (April 4,

1979). EPA has also noted that in certain situations,

such as where there are a limited number of sources

contributing to the nonattainment problem, where

requiring linear progress reductions in PM–10

emissions to maintain RFP is less appropriate and

in such situations an expeditious compliance

schedule can be used to demonstrate RFP. See 59

FR 41998, 42015.

33Under CAA section 193, guidance issued by

EPA prior to the 1990 CAA Amendments remain in

effect except to the extent that it is inconsistent

with any provision of the revised Act or is revised

by the Administrator. As will be seen, EPA has both

found that its previous RFP guidance requiring

linear emission reductions is inconsistent with the

statutory provisions allowing demonstration of

impracticability for moderate PM–10 areas and

revised that guidance for such areas.

2. Response to Comments on the RFP

Demonstration

EPA has responded to the most

significant comments on the proposed

RFP demonstration below. The TSD

contains EPA’s response to all

comments received.

Comment: ACLPI asserts that section

172(c)(2) of the Act specifically requires

all nonattainment area SIPs to show

RFP, and that both the Act and

longstanding EPA guidance require that,

to satisfy the RFP requirement, plans

must provide for annual reductions in

total emissions sufficient to produce

steady progress toward attainment on a

straight line basis or faster, citing CAA

section 171(1) and 59 FR 41988, 42016

(August 16, 1994); 52 FR 45044, 45066

(November 24, 1987); 46 FR 7182, 7185

(January 22, 1981); EPA, Guidance

Document for Correction of Part D SIP’s

for Nonattainment Areas (January 27,

1984). ACLPI disagrees with EPA’s

claim that for moderate areas

demonstrating impracticability, the

Act’s RFP requirement is met by a

showing that implementation of all

RACM will result in ‘‘incremental

emission reductions below preimplementation levels.’’ ACLPI asserts

that the Act does not in any way waive

the RFP requirement for moderate PM–

10 areas claiming impracticability and

explicitly sets out RFP as a requirement

separate, distinct and in addition to

RACM, comparing section

172(c)(1)(RACM) with section

172(c)(2)(RFP). ACLPI claims that EPA’s

reading of the RFP requirement for areas

demonstrating impracticability would

render the RFP mandate a mere

redundancy, a result that is contrary to

well-settled rules of statutory

construction, citing N.J. Singer, 2A

Statutes & Statutory Constr. § 46.06 at

119–20 (1992 Rev.).

Response: EPA agrees with ACLPI

that the RFP requirement in section

172(c)(2) is a separate and distinct

requirement for nonattainment plans

that is in addition to the requirement for

RACM in section 172(c)(1). It also agrees

that all nonattainment plans must

address the RFP requirement, including

moderate area PM–10 plans

demonstrating impracticability. EPA has

not waived the RFP requirement and

has fully addressed it in this FIP. See

section IV.D.1. Section 171(1) of the

CAA defines RFP as:

[S]uch annual incremental reductions in

emissions of the relevant air pollutant as are

required by [Part D of title I of the Clean Air

Act] or may reasonably be required by the

Administrator for the purpose of ensuring

attainment of the applicable national ambient

air quality standard by the applicable date.

As seen from this definition, the

adequacy of the emission reductions

required to demonstrate RFP is

inextricably linked to the reductions

necessary to ensure attainment and thus

to the control strategy necessary for

attainment. Because of this

interconnection, EPA has historically

required RFP to be demonstrated by

showing that nonattainment plans

provide for annual incremental

emission reductions sufficient generally

to maintain at least linear progress

toward attainment by the applicable

attainment deadline. See, e.g., 43 FR

21673, 21675 (May 19, 1978), Criteria

for Proposing approval of Revisions to

[1979] Plans for Nonattainment Areas;

46 FR 7185 (January 22, 1981), Approval

of 1982 Ozone and Carbon Monoxide

Plan Revisions for Areas Needing an

Attainment Date Extension [under CAA

section 172(a)(2)]; 59 FR 41988, 42016

(August 16, 1994), State Implementation

Plans for Serious PM–10 Nonattainment

Areas. As described, for example, in the

1978 guidance document, the required

linear reductions were represented

graphically as a straight line drawn from

the base year (i.e., the submittal year for

the plan) emission inventory to the

allowable emissions in the attainment

year. RFP was shown if the annual

emission reductions were sufficient to

produce this ‘‘straight-line rate.’’ 32 See

43 FR 21675.

Since this straight-line rate

demonstration requires a determination

of the emission reductions needed for

attainment, the guidance documents

requiring linear progress for RFP in

nonattainment plans has always been

predicated on the existence of a

concurrent statutory requirement that

the nonattainment plan also

demonstrate attainment. These guidance

documents, however, provide little help

in determining how RFP is to be

demonstrated when a nonattainment

plan is statutorily allowed not to

demonstrate attainment, as is the case

with certain moderate area PM–10

plans.

Moderate area PM–10 plans

demonstrating impracticability do not

include a projection of the allowable

emissions in the attainment year.

Attainment projections for such areas

are not required until submittal of the

subsequent serious area plan. Thus, for

moderate plans demonstrating

impracticability, it is not possible to

determine the linear rate of reductions

required under the RFP guidance for

plans demonstrating attainment because

the line’s end point, the allowable

attainment level, is missing. Put simply,

EPA’s previous interpretation of and

guidance for the RFP requirement in the

Act do not work in areas demonstrating

impracticability. In such a situation, it

is necessary and appropriate to amend

the previous guidance.33

EPA issued preliminary guidance on

interpreting the RFP requirement for

moderate PM–10 areas demonstrating

impracticability in its final approval of

the Phoenix moderate area PM–10 plan,

noting that the guidance was intended

to clarify the confusion created by

omissions in the Act and in prior EPA

guidance. See 60 FR 18010, 18013

(April 10, 1995). In that notice, EPA

stated that RFP was demonstrated by

showing that the implementation of all

RACM has resulted in ‘‘incremental

reductions’’ in emissions of PM–10.

EPA clarified and further explained this

guidance in its proposal to restore the

Agency’s approval of the Phoenix

moderate area plan. See 61 FR 54972,

54973. As quoted above, RFP is defined

in section 171(1) as either annual

incremental reductions as are required

under part D, or such reductions as the

Administrator may reasonably require

‘‘for the purpose of ensuring attainment

of the [NAAQS] by the applicable date.’’

In moderate PM–10 area plans

demonstrating impracticability, there is

no demonstration of attainment, simply

a demonstration that, even after the

implementation of all RACM, it is

impracticable for the area to attain the

PM–10 standard by the applicable

attainment deadline. Once EPA has

determined that all reasonable control

measures that are available have been

implemented and timely attainment still

will not occur, there are no further

reductions that it would be reasonable

to require ‘‘for the purpose of ensuring

attainment’’ by the applicable

attainment deadline. Thus, the

emissions reductions achieved through
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41345

34EPA’s approach is consistent with the rule,

long articulated by the Ninth Circuit, that ‘‘language

in one section of the statute [is to be interpreted]

consistently with the purposes of the entire statute

considered as a whole.’’ Adams v. Howerton, 673

F.2d 1036, 1040 (9th Cir.), cert. denied, 458 U.S.

1111 (1982). See also In re Arizona Appetito’s

Stores, Inc., 893 F.2d 216, 219 (9th Cir. 1990)

(courts to adopt interpretation that is harmonious

with the statute’s scheme and general purposes).

35 In light of the new statutory provisions in the

1990 Clean Air Act Amendments, ACLPI’s

comment that EPA’s position is comparable to that

rejected by the Ninth Circuit in Delaney is

inapposite. In that case, the Court was addressing

the consequences of a lapsed attainment deadline

in the absence of any related statutory provisions.

In the 1990 Amendments, Congress provided

specific actions to be undertaken should such a

lapse occur.

implementation of all RACM, by

definition, would satisfy the

requirement to demonstrate reasonable

further progress in the period before the

Act requires a new plan that includes

the additional measures needed to

produce the net emissions reductions

required for attainment.

Moreover, EPA’s interpretation is

reasonable given the Act’s scheme for

PM–10 attainment. Among all the Act’s

numerous nonattainment requirements,

the moderate area PM–10 provisions are

unique in tolerating a planned failure to

demonstrate attainment and deferring

the obligation to demonstrate attainment

to a later plan. EPA’s interpretation of

the general RFP requirement in section

172(c)(2), as it applies to moderate PM–

10 areas demonstrating impracticability,

must not only meet the Act’s definition

of RFP but must also be consistent with

the statutory scheme for PM–10

attainment. For the reasons stated

above, EPA believes that its

interpretation of the RFP requirement

for areas demonstrating impracticability

is consistent with this scheme.

Requiring RFP demonstrations to show

emission reductions in excess of those

resulting from the implementation of all

RACM would conflict with the CAA

section 189(a)(1)(B)(ii) provision for

demonstrating impracticability.34

Finally, this entire discussion is

somewhat academic in the case of this

FIP where the expeditious application

of RACM not only results in incremental

emission reductions below preimplementation levels, but also in

annual incremental reductions for both

the 24-hour and annual PM–10

standards. See section IV.D.1.

Comment: In its 1996 comments

(which the Center requested be

incorporated into its comments on the

April 1, 1998 PM–10 FIP proposal),

ACLPI argues that EPA wrongly suggests

that the Act’s RFP mandate disappears

after the applicable attainment date has

passed and does not reappear until the

state submits a new SIP to meet a new

attainment deadline. The Center asserts

that under this view, a state that is

delinquent in meeting an attainment

deadline can actually do less to move

toward attainment than an area that has

yet to miss a deadline. Given that the

whole purpose of the RFP mandate is to

assure steady progress toward clean air,

ACLPI argues that the purpose becomes

even more urgent when an area is

continuing to violate standards and that

EPA’s position is comparable to that

rejected by the Court in Delaney v. EPA,

898 F.2d 687 (9th Cir. 1990). In

addition, ACLPI argues that the

approach proposed by EPA could not be

more antithetical to the language and

purpose of the CAA and that under such

an approach, EPA could approve a SIP

that will actually allow air quality to

worsen since the SIP need only slow the

rate of emissions growth until the

attainment deadline but after the

attainment deadline, the SIP need not

even slow the rate of emissions growth

and emissions can grow at any rate.

ACLPI asserts that it is inconceivable

that Congress intended a result so

contrary to the public health goals of the

Act, or to the plain meaning of the

phrase, ‘‘reasonable further progress.’’

Response: As stated above, the RFP

mandate in the Act is intended to

ensure that nonattainment plans

provide for reasonable progress toward

attainment by the applicable attainment

date, as is clear from the plain language

of the RFP definition in section 171(1)

of the Act. As is apparent from that

language, RFP, as the term is used in the

CAA, applies only in the period prior to

the applicable attainment date and does

not continue in the period after that

date.

ACLPI purports to invest in the RFP

mandate the solution to all potential

problems with implementation plans,

from delinquent plans and failure to

actually attain the standards, to

increasing emissions after attainment

dates have passed. This allencompassing view of the RFP mandate

ignores the provisions of the Act that

Congress added to specifically address

each of these situations: the section

179(a) sanctions and section 110(c)

federal plan requirements for addressing

delinquent or inadequate plans; the

reclassification requirements of sections

181(b)(2), 186(b)(2), and 188(b) (with

their accompanying requirements for

new plans in sections 182, 187, and 189)

and the mandatory rate of progress

requirements in sections 187(g) and

189(d) for addressing continuing

violations after the serious area

attainment date has passed; the

requirement for contingency measures

in section 172(c)(9) to assure additional

emission reductions after an area fails to

attain but before a new plan is

submitted to prevent emissions growth;

and the maintenance plan requirements

in section 175(A) to assure limits on

emissions growth to prevent violations

of the standard in areas redesignated to

attainment.35

Given that there are other specific

CAA provisions that address the

hypothetical scenarios ACLPI envisions,

there is no basis for invoking the general

RFP provision as a gap-filling, allpurpose remedy for them. EPA’s

interpretation of the section 172(c)(2)

RFP requirement as set forth in the FIP

is consistent with the statutory purpose

of achieving regular emission reductions

as needed to assure attainment by the

applicable attainment date.

Comment: ACLPI comments that the

Act’s reclassification scheme does not

support EPA’s RFP approach because

the purpose of reclassification is to

prompt adoption of more stringent

controls and not an excuse to bring

progress to a stop.

Response: EPA does not claim that the

reclassification scheme supports its RFP

approach. Equally, the reclassification

scheme does not support ACLPI’s

proposition that the RFP requirement

should apply after an applicable

attainment date. As noted previously,

the plain language of the RFP definition

clearly indicates that RFP is only

required in the period before the

applicable attainment date and not after

it has passed. As also noted previously,

the CAA provision intended to address

progress between a lapsed attainment

date and the submittal of a revised

nonattainment plan with its new RFP

demonstration is the contingency

measures provision in section 172(c)(9).

Comment: ACLPI claims that EPA’s

RFP analysis for the proposed FIP is

flawed in several other key respects.

First, ACLPI asserts that it is based on

an emissions inventory that is not

complete, current, and accurate, as

required by the Act. ACLPI states that

the inventory submitted by the state in

connection with its 1991/1993 PM SIP

revision showed vehicular exhaust as

constituting 36 percent of total PM–10

emissions (ADEQ, Final State

Implementation Plan Revision, Revised

Chapter 9 (Feb. 1994) p. 9–34) and in

contrast, the inventory relied on in

EPA’s current RFP demonstration shows

the same sources as amounting to only

8 percent of the inventory and that EPA

offers no rational explanation for this

glaring disparity. ACLPI notes that the

State’s prior inventory was based on
41346 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

36Strictly speaking, this normalized inventory is

not an emission inventory at all, but merely the

percent source contributions at a monitor

multiplied by the total regional inventory as

calculated by emission factors and source activity

levels.

37 In the 1991/93 Plan, the primary purpose of the

normalized inventory was to evaluate the effects of

controls for the impracticability demonstration. See

1991/93 Plan, p. 9–39.

actual speciated monitoring data from

the Phoenix area and that EPA’s

inventory appears to based on

theoretical emission factors and

speculation.

Response: EPA based its RFP analysis

for the proposed FIP on the 1994

regional emission inventory prepared by

MAG (see 1994 Regional PM–10

Emission Inventory for the Maricopa

County Nonattainment Area, Draft Final

Report, MAG, May 1997) and additional

inventory work prepared for the

regional PM–10 modeling (see

Technical Support Document for the

Regional PM–10 Modeling in Support of

the 1997 Serious Area PM–10 Plan for

Maricopa County Nonattainment Area,

Draft, MAG, October 1997). These

inventories were prepared following the

procedures in EPA guidance, using

either EPA emission factors or other

appropriate emission factors and

Phoenix-specific activity data.

It is not valid to conclude from the

mere fact that this inventory differs in

its apportionment of sources from the

inventory in the 1991/93 PM SIP that

the regional 1994 inventory is

inherently flawed. Inventories prepared

at different times will naturally vary

because improved methodologies are

developed, new information about

sources is collected, control measures

are implemented, and emission growth

rates vary across categories. All these

factors tend to affect the percentage

presence of a source category from

inventory to inventory. Because it is the

nature of inventories to change over

time, EPA does not normally require

new inventories to be reconciled against

previous ones and any differences

between them explained.

The inventory in the 1991/93 PM–10

Plan referred to by ACLPI is the regional

inventory modified (‘‘normalized’’) to

reflect a 1989–1990 source

apportionment at three urban Phoenix

monitors: Central Phoenix, West

Phoenix, and South Scottsdale. 36 This

source apportionment was performed

using Chemical Mass Balance (CMB)

modeling and monitored speciated data.

As work has been done to evaluate the

nature of the PM–10 problem in

Phoenix, it has become increasing clear

that PM–10 exceedances in the Phoenix

area often have highly localized causes.

In other words, the sources that

contribute substantially to an

exceedance are often located close to the

exceeding monitor. As a result, any

inventory that is developed based on the

source apportionment from a given

monitor or small set of similar monitors

is only truly informative about the

relative significance of sources around

those monitors rather than about the

relative significance of sources in a

regional inventory.

Phoenix has a large number of fugitive

dust sources such as construction sites,

vacant lots, unpaved roads, and

agricultural fields. Emissions from these

sources need to be included in any

regional inventory. However, as noted

in EPA’s proposed action on the

microscale plan, fugitive dust PM–10

has more localized effects than other

criteria pollutants because it is emitted

near ground level and has relatively

sharp spatial concentration gradients as

dust settles out with distance from the

emitting source. See 62 FR 31025,

31030. Consequently, it would be

surprising to see a substantial

contribution from fugitive dust sources

at urban monitors where there were

relatively few of these fugitive dust

sources close by. The source

apportionment at such monitors is

much more likely to be influenced by

local sources such as paved road dust

and by fine particulate sources, such as

vehicle exhaust, which tend to remain

suspended in ambient air longer. This is

exactly the source apportionment seen

at the three urban monitors used to

generate the 1991/93 Plan’s normalized

inventory. As a result, it is not

surprising to see that the 1991/93 Plan’s

normalized inventory skewed toward

paved road dust and vehicle exhaust

and away from fugitive dust. Basing the

regional inventory on the source

apportionment at urban monitors,

however, will underestimate regional

fugitive dust emissions. This

underestimation is illustrated in the

1991/93 Plan’s normalized inventory in

which fugitive dust sources account for

only 3 percent of the total regional PM–

10 emissions.

Source apportionment at a monitor is

a necessary part of preparing a PM–10

attainment demonstration because

without a clear understanding of the

relative contributions of sources causing

an exceedance, it is impossible to know

how controls will affect air quality.37

But in preparing a regional inventory for

an area as large and as diverse as

Phoenix, with its many fugitive dust

sources, source apportionment based on

just a few urban monitors is unlikely to

result in a regional inventory that

correctly accounts for fugitive dust

emissions.

Comment: ACLPI also asserts that

EPA failed to accurately address growth

in PM–10 emissions from vehicular

exhaust. ACLPI notes that the Agency’s

inventory shows on-road exhaust

emissions of PM–10 steadily decreasing

from 1610 tpy in 1995 to 1037 tpy in

2001, but cites a MAG conformity

analysis that shows vehicle exhaust

emissions of PM–10 increasing to 8,807

tpy (based on 24.13 tpd) by 2001. ACLPI

argues that increased emissions are

consistent with projected increases in

VMT and with the lack of additional

controls to limit motor vehicle

emissions of PM–10 and that EPA

cannot justify reliance on an inventory

that shows decreasing motor vehicle

emissions when this conflicts with

reality.

Response: The MAG conformity

analysis is performed using an out-ofdate mobile source emissions model, the

1985 Particulate Model. See Conformity

Analysis, MAG Long Range

Transportation Plan Summary and 1997

Update [and] MAG 1998–2002

Transportation Improvement Program,

MAG, November 1997, p. 1–21. MAG

uses this model in its conformity

determinations in order to be consistent

with the model used in the State’s 1991/

93 moderate area plan. In 1994, EPA

released the PART5 mobile source

model for use in SIPs. As recommended

by EPA guidance, the base and projected

exhaust emission inventories in the FIP

were developed using the PART5

model. See PM–10 Emission Inventory

Requirements, OAQPS, EPA (EPA–454/

R–94–033), September 1994, p. 14. The

PART5 model changed the estimates of

emissions from on-road motor vehicles.

The difference between the conformity

and FIP inventories is partly related to

this change in emission models.

The difference between the two

inventories is also the result of the use

of the normalized inventory from the

1991/93 PM–10 Plan in the conformity

analysis. Again, MAG uses the

normalized inventory to be consistent

with the submitted PM–10 SIP. See

Conformity Analysis, p. 1–20. As

discussed in the previous response, this

normalized inventory substantially

increased the vehicle exhaust portion of

the inventory based on the source

apportionment at three urban monitors.

This normalized inventory does not

accurately reflect the contribution of

fugitive dust sources to the regional

inventory and probably overstates

vehicle exhaust emissions.

Because the motor vehicle exhaust

inventory in the MAG conformity

analysis and the inventory in the FIP
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41347

38When projected 2001 emissions are estimated

using the same methodology as used in the 1991/

93 plan, motor vehicle exhaust PM–10 emissions

are projected to decline from 13,410 mtpy in 1989

(1991/93 Plan, p. 9–41, figure converted to mtpy

from english tpy) to 8,807 mtpy in 2001 (Conformity

Analysis, p. 6–3).

39The County typically only ensures compliance

with Rule 310 for these sources on a complaint

basis.

were developed using substantially

different methodologies and

assumptions, the inventories are not

comparable. As a result, it cannot be

said that motor vehicle emissions are

increasing from 1610 mtpy to 8,807

mtpy as ACLPI claims.38 The motor

vehicle exhaust inventory used in the

FIP was based on the EPA’s latest

emission model and regional estimates

of emissions and, as a result, EPA

believes that it is the best inventory

currently available.

Contrary to ACLPI’s assertions, it is

not surprising to see decreases in

tailpipe PM–10 emissions despite the

increases in VMT and the apparent lack

of additional new control measures.

This decline in emissions despite the

substantial increase in VMT is due

primarily to fleet turnover that brings

cleaner cars into the fleet to replace

older, dirtier ones and implementation

of control programs such as I/M and

clean fuel requirements. Decreasing

motor vehicle emissions, in fact, reflects

the reality of almost three decades of

successful technological controls on

motor vehicles.

Comment: ACLPI states that the RFP

demonstration does not show annual

emission reductions—it only purports to

show reductions in the year 2001.

Response: As discussed above, EPA

does not believe that annual emission

reductions are necessary to demonstrate

RFP in areas demonstrating the

impracticability of attaining the PM–10

standard. However, EPA has

qualitatively shown that this FIP should

result in annual emission reductions

from the 1998 promulgation until the

December 31, 2001 attainment date.

E. Indian Reservations

As discussed in EPA’s proposed FIP,

there are two Indian reservations (the

Salt River Pima-Maricopa Indian

Community and the Fort McDowell

Mojave-Apache Indian Community) and

a portion of a third reservation (the Gila

River Indian Community) in the

Phoenix PM–10 nonattainment area.

The FIP measures do not cover sources

on these reservations. See 63 FR 15920,

15941. EPA received comments from the

Salt River Pima-Maricopa Indian

Community supporting EPA’s proposal

and reiterating their willingness to work

with EPA under the EPA’s Tribal

Authority Rule which became effective

on March 16, 1998.

V. 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. Regulatory Flexibility Analysis

1. Regulatory Flexibility Act

Requirements

Under the Regulatory Flexibility Act

(RFA), 5 U.S.C. section 601 et. seq., EPA

must prepare a regulatory flexibility

analysis assessing the impact of any

proposed or final rule on small entities

unless EPA certifies that the rule will

not have a significant economic impact

on a substantial number of small

entities. 5 U.S.C. 603, 604 and 605(b).

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 two proposed federal

measures, the fugitive dust rule and the

commitment for the development and

implementation of RACM for the

agricultural sector, EPA is assuming that

the affected or potentially affected

sources constitute ‘‘small entities’’ as

defined by the RFA.

The final federal measures are

intended to fill gaps in the Arizona PM–

10 SIP for the Phoenix nonattainment

area. For non-agricultural fugitive dust

sources, while the County has adopted

and EPA has approved Rule 310 into the

SIP, the County has not made a

commitment to provide adequate

resources to ensure enforcement of the

rule as it applies to the unpaved road,

unpaved parking lot and vacant lot

source categories.39 Further, application

of Rule 310 to agricultural sources

including fields and aprons is affected

by the provision in section 102

(incorporating A.R.S. 49–504.4) that

states that the rule ‘‘shall not be

construed so as to prevent normal farm

cultural practices.’’ Therefore,

applicability of the rule to such sources

depends on what dust-generating

operation is occurring at the source. In

other words, Rule 310 applies to some

operations on agricultural fields and

aprons and not to others.

2. RFA Analysis

a. Federal Rule for Unpaved Roads,

Unpaved Parking Lots, and Vacant Lots.

The starting point for EPA’s analysis is

Maricopa County’s Rule 310. Regardless

of the County’s resources for enforcing

the rule with respect to nonagricultural

fugitive dust sources, those sources are

legally responsible for complying with

it. Failure to do so subjects such sources

to potential enforcement action by EPA,

the State, County and/or citizens. Thus,

for the purpose of analyzing whether the

proposed FIP rule will have ‘‘a

significant economic impact,’’ EPA

assumes that sources subject to the rule

are complying with it. The appropriate

inquiry then is whether the terms of

EPA’s proposed rule would impose a

significant economic impact beyond

that imposed by the terms of Rule 310.

Section 101 of Rule 310 states that the

purpose of the rule is ‘‘[t]o limit the

emission of particulate matter into the

ambient air from any property,

operation or activity that may serve as

an open fugitive dust source.’’ Further,

the provisions of the rule ‘‘apply to any

activity, equipment, operation and/or

man-made or man-caused condition or

practice * * * capable of generating

fugitive dust. * * *’’ Sections 305, 306,

309 and 312 of the rule contain the

regulatory requirements applicable to

the following source categories: vehicle

use in open areas and vacant parcels,

unpaved parking areas, vacant areas,

and roadways. These requirements

differ to some extent depending on the

source category, but generally they

mandate the implementation of RACM

before certain dust-producing activities

can be undertaken. RACM is defined in

section 221 as ‘‘[a] technique, practice,

or procedure used to prevent or
41348 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

40EPA believes that it is reasonable and

appropriate for its rule to be more specific and

detailed than the County rule. As a result of the

State’s failure to commit sufficient enforcement

resources for its rule, EPA is having to fulfill the

role of primary enforcer of the RACM requirement

for the sources described above. EPA Region 9 will

be responsible for fulfilling that role, and it is

located in San Francisco. Given the greater

difficulties that Region 9 will inevitably face in

enforcing the RACM requirement in Arizona, it is

reasonable for EPA to design a RACM rule that

ensures EPA enforcement of the rule will be

practicable. As described above, the County rule

provides a general basis for determining which

RACM should be applied to which source

categories. But its lack of specificity makes it more

likely that the agency enforcing the rule will

routinely be called upon to address which RACM

should be applied to which source categories. By

addressing this issue in the FIP rule itself, EPA

hopes to reduce the extent to which sources and

others may have to consult with the Agency to

determine which RACM are appropriate for a

particular source or source category.

41Since, by its terms, the requirements of Rule

310 are so broad, the general effect of the greater

specificity and detail is that EPA’s FIP rule, in its

entirety, is somewhat narrower in scope than the

County’s rule as it relates to unpaved roads,

unpaved parking lots and vacant lots. For example,

section 312 of Rule 310 regulates users of unpaved

roads, while EPA’s rule regulates only owners and

operators; and Rule 310 does not exempt any

unpaved roads, while EPA’s rule includes a low

ADT exemption.

minimize the generation, emission,

entrainment, suspension and/or

airborne transport of fugitive dust.’’ As

further defined in subsection 221.1, and

as pertinent to this analysis, RACM

include, but are not limited to: curbing,

paving, applying dust suppressants,

and/or physically stabilizing with

vegetation and gravel.

While subsection 211.1 does not

specify which of the listed measures are

appropriate for what types of source

categories, the general definition of

RACM in section 221 together with the

list of RACM measures in subsection

211.1 provide a basis for selecting

measures which are appropriate for a

particular source to prevent or minimize

dust emissions, to the extent other

provisions of Rule 310 do not specify a

particular RACM measure.

EPA’s final fugitive dust rule is

intended to establish a RACM

requirement for unpaved parking lots,

unpaved roads and vacant lots that is

substantively equivalent to that

established for the same sources by the

Maricopa County rule. As noted above,

the requirements of the County rule

differ to some extent depending on the

source category; EPA’s proposed rule

mirrors those differences. The primary

difference between the County rule and

EPA’s final rule is that the EPA rule

provides greater specificity and detail

regarding which RACM are appropriate

for a particular source category for the

purpose of preventing or minimizing

fugitive dust emissions.40

In providing further specificity and

detail, EPA’s rule does not change the

nature of the RACM requirement

already applicable to sources covered by

County Rule 310. The RACM required to

be applied in the final FIP rule are the

very measures listed in subsection 211.1

of Rule 310. Beyond that, the RACM

specified in the final rule for any

particular source category are the

appropriate RACM for that source

category. What constitutes RACM for

the source categories covered by the

final FIP rule is relatively

straightforward in light of the

differences among the source categories,

the low technology nature of the

potential RACM and other available

information. EPA therefore believes that

its further specification of the RACM

requirements does not change the nature

of the RACM requirements already

applicable under Maricopa County Rule

310 which is federally enforceable as an

approved element of the Arizona SIP.

The only other notable difference

between the County rule and the final

FIP rule that is relevant to this analysis

is paragraph (f) of the proposed FIP rule.

Rule 310 contains a recordkeeping

requirement for permitted dustgenerating activities, but does not

contain such a requirement for

unpermitted activities, including

unpaved parking lots, unpaved roads

and vacant lots. Therefore, paragraph (f)

of the proposed FIP rule includes a

requirement that owners/operators

subject to the rule maintain records

demonstrating appropriate application

of RACM. EPA has determined that the

recordkeeping requirements for the

source categories covered in the FIP rule

will not have a significant economic

impact. In many cases, the owner/

operator need only retain a purchase

receipt or contractor work order for the

control(s) implemented. When chemical

stabilization is applied as a control

measure, more specific information

regarding the product being used is

required. However, this information

(e.g., type of product, label instructions)

is readily available from vendors or

easily determined at the time of

application. EPA expects that the

information the final FIP rule requires

sources to keep will be retained by

source owners or operators in any event

in the normal course of business (e.g.,

for tax and accounting purposes).

EPA’s final fugitive dust rule

incorporates a number of changes made

in response to the public comments that

EPA received on the FIP proposal.

Those changes are summarized and

discussed in section IV.B.2. above and

in the TSD. The net result of the

substantive changes is to provide

sources with greater flexibility than

provided in the FIP proposal and Rule

310. For example, the final FIP rule

includes an increase from 0.10 acre to

0.50 acre in the de minimis disturbed

surface area level for vacant lots; an

increase from 150 to 250 ADT in the

exemption level for unpaved roads; a

new de minimis use level for unpaved

parking lots; and the elimination of the

DCP requirement for weed abatement.

As a result of these and other changes,

the requirements of the final FIP rule are

effectively less stringent than both the

rule as proposed and Rule 310. Thus the

costs of compliance with the FIP rule

are expected to be less than the

proposed FIP rule and Rule 310.

As the above discussion of the RACM

requirements of the two rules makes

clear, even though the final FIP rule

differs from Rule 310 in that it is more

specific and detailed, there should be no

additional burden on regulated sources

because they are already legally

required to apply RACM under the

County rule, and the RACM required by

the final FIP rule are substantively

identical to that required under Rule

310.41

Moreover, EPA believes that the

additional recordkeeping requirement in

the FIP rule will not have a significant

economic impact on the affected

sources. As stated above, and in section

V.A.7.b. of the proposed rulemaking, the

information required to be retained is

minimal and is therefore not expected to

entail any appreciable economic impact.

b. Federal Commitment for

Agriculture. EPA’s final measure to

control fugitive dust from agricultural

fields and aprons consists of an

enforceable commitment to propose and

finalize adoption of RACM for those

sources in September 1999 and April

2000, respectively. Prior to this formal

rulemaking, EPA intends to convene a

stakeholder process to develop the

specific RACM that will ultimately be

proposed for adoption. As discussed in

detail in section V.A.7.a. of the

proposed rulemaking, EPA intends the

RACM to take the form of BMPs. During

the BMP development process, EPA will

investigate a myriad of factors,

including the appropriate coverage of

potential BMPs, regional climate, soil

and crop types, and growing seasons.

Because this aspect of today’s action

neither imposes specific regulatory

requirements, nor obligates EPA to

propose requirements necessarily

applicable to small entities, it will not,

by itself, have a significant economic

impact on a substantial number of small

entities. When EPA proposes specific

RACM in the September 1999
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41349

rulemaking, it will either undertake a

RFA analysis or certify the proposed

rule, as appropriate.

c. Certification. EPA has determined

that it is not necessary to prepare a

regulatory flexibility analysis in

connection with this final rule. EPA has

also determined that this rule will not

have a significant economic impact on

a substantial number of small entities.

C. 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.

Under section 202 of the UMRA, EPA

generally must prepare a written

statement, including a cost-benefit

analysis, when EPA promulgates ‘‘any

general notice of proposed rulemaking

that is likely to result in promulgation

of any rule that includes any Federal

mandate that may result in the

expenditures by State, local, and tribal

governments, in the aggregate, or by the

private sector, of $100 million or more’’

in any one year. A ‘‘Federal mandate’’

is defined, under section 101 of UMRA,

as a provision that ‘‘would impose an

enforceable duty’’ upon the private

sector or State, local, or tribal

governments’’, with certain exceptions

not here relevant.

Under section 203 of UMRA, EPA

must develop a small government

agency plan before EPA ‘‘establish[es]

any regulatory requirements that might

significantly or uniquely affect small

governments’.

Under section 204 of UMRA, EPA is

required to develop a process to

facilitate input by elected officers of

State, local, and tribal governments for

EPA’s ‘‘regulatory proposals’’ that

contain significant Federal

intergovernmental mandates.

Under section 205 of UMRA, before

EPA promulgates ‘‘any rule for which a

written statement is required under

[UMRA section] 202’’, EPA must

identify and consider a reasonable

number of regulatory alternatives and

either adopt the least costly, most costeffective or least burdensome alternative

that achieves the objectives of the rule,

or explain why a different alternative

was selected.

As explained above, while the final

federal fugitive dust rule may impose an

enforceable duty on State or local

governments, the resulting expenditures

by those entities are expected to be

minimal. Tribal governments are

excluded from the coverage of this rule.

In addition, there will be no current

enforceable duties imposed on, or

expenditures by, State, local or tribal

governments or the private sector as a

result of the federal commitment

regarding the agricultural sector.

Therefore, expenditures by State, local

and tribal governments, in the aggregate,

or by the private sector, will be well

under $100 million per year as a result

of today’s federal measures.

Consequently, sections 202, 204 and 205

of UMRA do not apply to today’s final

action. Therefore, EPA is not required

and has not taken any actions to meet

the requirements of these sections of

UMRA.

With respect to section 203 of UMRA,

EPA has concluded that its final actions

include no regulatory requirements that

will significantly or uniquely affect

small governments. As discussed in

detail in IV.B.2. above, EPA believes

that the RACM requirements of the final

FIP rule for vacant lots, unpaved

parking lots and unpaved roads are

already legally required under Maricopa

County Rule 310 which is federally

enforceable as an approved element of

the Arizona SIP. Moreover, the

requirements of EPA’s final FIP rule,

while more specific and detailed, are

substantively identical to those required

under Rule 310. Therefore, there should

be no additional burden on regulated

sources, including small governments.

With respect to EPA’s enforceable

commitment for the agricultural sector,

such a commitment neither imposes

specific regulatory requirements, nor

obligates EPA to propose requirements

necessarily applicable to small entities.

Thus, neither EPA’s fugitive dust rule

nor its commitment for the agricultural

sector will significantly or uniquely

affect small governments. Consequently,

EPA has not developed a small

government plan. Nevertheless, prior to

EPA’s proposed action, the Agency held

numerous meetings with potentially

affected representatives of the State and

local governments to discuss the

requirements of, and receive input

regarding, the proposed federal fugitive

dust rule and commitment for the

agricultural sector.

D. Paperwork Reduction Act

The information collection

requirements in this final rule have been

submitted for approval to the Office of

Management and Budget (OMB) under

the Paperwork Reduction Act, 44 U.S.C.

3501 et seq. An Information Collection

Request (ICR) document has been

prepared by EPA (ICR No. 1855.02) and

a copy may be obtained from Sandy

Farmer, OPPE Regulatory Information

Division; U.S. Environmental Protection

Agency (2137); 401 M St., S.W.;

Washington, DC 20460 or by calling

(202) 260–2740.

EPA’s final FIP rule for unpaved

parking lots, unpaved roads and vacant

lots includes recordkeeping and

reporting requirements which will help

ensure source compliance with the

rule’s control requirements. In general,

EPA believes the recordkeeping and

reporting requirements are the minimal

requirements necessary to demonstrate

compliance. The requirements include:

—Owners/operators of unpaved roads

must keep a record which indicates

the date and type of control (i.e.,

paving, stabilizing, or applying gravel)

applied to the road.

—Owners/operators of unpaved parking

lots must keep a record which

indicates the date and type of control

(i.e., paving, stabilizing, applying

gravel, or temporary stabilization for

lots used less than 35 days per year)

applied to the unpaved parking lot.

—Owners/operators of vacant lots with

disturbed surfaces must keep a record

which indicates the date and type of

control (i.e., applying ground cover

vegetation, stabilizing, restoring to

natural undisturbed state, or applying

gravel) applied to the vacant lot.

—Owners/operators of vacant lots with

motor vehicle disturbances must keep

a record which indicates the date and

type of control applied to the vacant

lot.

—Agency surveys will be conducted by

the EPA or other appropriate agency

to determine the effectiveness of the

rule in the Phoenix area.

The estimated recordkeeping and

reporting burden for the proposed FIP

rule was about 9716 hours and the

estimated labor cost was about

$173,632. However, since the final FIP

rule no longer requires the submittal of

dust control plans for weed abatement

activity, the estimated recordkeeping

and reporting burden for the final FIP

rule is about 5297 hours and the

estimated labor cost is about $93,455.

No capital/start-up costs or operational

and maintenance costs are anticipated.

Burden means the total time, effort, or

financial resources expended by persons

to generate, maintain, retain, or disclose

or provide information to or for a

Federal agency. This includes the time

needed to review instructions; develop,

acquire, install, and utilize technology

and systems for the purposes of

collecting, validating, and verifying

information, processing and

maintaining information, and disclosing

and providing information; adjust the

existing ways to comply with any

previously applicable instructions and
41350 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

requirements; train personnel to be able

to respond to a collection of

information; search data sources;

complete and review the collection of

information; and transmit or otherwise

disclose the information.

An agency may not conduct or

sponsor, and a person is not required to

respond to a collection of information

unless it displays a currently valid OMB

control number. The OMB control

number for EPA’s regulations is listed in

40 CFR Part 9 and 48 CFR Chapter 15.

Send comments on the Agency’s need

for this information, the accuracy of the

provided burden estimates, and any

suggested methods for minimizing

respondent burden, including through

the use of automated collection

techniques, to the Director, OPPE

Regulatory Information Division; U.S.

Environmental Protection Agency

(2137); 401 M St., S.W.; Washington, DC

20460; and to the Office of Information

and Regulatory Affairs, Office of

Management and Budget, 725 17th St.,

N.W. Washington, DC 20503, marked

‘‘Attention: Desk Officer for EPA.’’

Comments are requested by September

2, 1998. Include the ICR number in any

correspondence.

E. E.O. 13045: Protection of Children

From Environmental Health Risks and

Safety Risks

Executive Order 13045, entitled

‘‘Protection of Children from

Environmental Health Risks and Safety

Risks (62 FR 19885 (April 23, 1997)),

applies to any rule that EPA determines

(1) ‘‘economically significant’’ as

defined under E.O. 12866 and (2) the

environmental health or safety risk

addressed by the rule has 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.

Today’s final action promulgating a

moderate area PM–10 federal

implementation plan for the Phoenix

area is not subject to E.O. 13045 because

it is not an economically significant

regulatory action as defined by E.O. and

because it does not involve decisions on

environmental health risks or safety

risks that may disproportionately affect

children.

F. Submission to Congress and the

General Accounting Office

The Congressional Review Act, 5

U.S.C. 801 et seq., as added by the Small

Business Regulatory Enforcement

Fairness Act of 1996, generally provides

that before a rule may take effect, the

agency promulgating the rule must

submit a rule report, which includes a

copy of the rule, to each House of the

Congress and to the Comptroller General

of the United States. EPA will submit a

report containing this rule and other

required information to the U.S. Senate,

the U.S. House of Representatives, and

the Comptroller General of the United

States prior to publication of the rule in

the Federal Register. This rule is not a

‘‘major’’ rule as defined by 5 U.S.C.

804(2).

G. Petitions for Judicial Review

Under section 307(b)(1) of the Clean

Air Act, petitions for judicial review of

this action must be filed in the United

States Court of Appeals for the

appropriate circuit by October 2, 1998.

Filing a petition for reconsideration by

the Administrator of this final rule does

not affect the finality of this rule for the

purposes of judicial review nor does it

extend the time within which a petition

for judicial review may be filed, and

shall not postpone the effectiveness of

such rule or action. This action may not

be challenged later in proceedings to

enforce its requirements. (See section

307(b)(2)).

List of Subjects in 40 CFR Part 52

Environmental protection, Air

pollution control, Intergovernmental

relations, Particulate matter, Reporting

and recordkeeping requirements.

Dated: July 17, 1998.

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

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 52.123 is amended by

adding paragraph (h) to read as follows:

§ 52.123 Approval Status.

* * * * *

(h) Pursuant to the federal planning

authority in section 110(c) of the Clean

Air Act, the Administrator finds that the

applicable implementation plan for the

Maricopa County PM–10 nonattainment

area provides for the implementation of

reasonably available control measures as

required by section 189(a)(1)(C) and

demonstrates attainment by the

applicable attainment date as required

and allowed by sections 172(c)(2) and

189(a)(1)(B).

3. Section 52.124 is amended by

adding paragraph (c) to read as follows:

§ 52.124 Part D disapproval.

* * * * *

(c) The Administrator disapproves the

attainment demonstration for the annual

PM–10 national ambient air quality

standard and the provisions for

implementation of reasonably available

control measures for the annual PM–10

national ambient air quality standard in

the MAG 1991 Particulate Plan for PM–

10 for the Maricopa County Area and

1993 Revisions (July 1993) submitted by

the Arizona Department of

Environmental Quality on August 11,

1993 as revised by the submittal of a

Revised Chapter 9 on March 3, 1994

because they do not meet the

requirements of sections 189(a)(1)(B)

and 189(a)(1)(C) of Part D of title I of the

Clean Air Act.

4. Subpart D is amended by adding

§§ 52.127 and 52.128 to read as follows:

§ 52.127 Commitment to promulgate and

implement reasonably available control

measures for the agricultural fields and

aprons.

The Administrator shall promulgate

and implement reasonably available

control measures (RACM) pursuant to

section 189(a)(1)(C) of the Clean Air Act

for agricultural fields and aprons in the

Maricopa County (Phoenix) PM–10

nonattainment area according to the

following schedule: by no later than

September, 1999, the Administrator

shall sign a Notice of Proposed

Rulemaking; by no later than April,

2000, the Administrator shall sign a

Notice of Final Rulemaking; and by no

later than June, 2000, EPA shall begin

implementing the final RACM.

§ 52.128 Rule for unpaved parking lots,

unpaved roads and vacant lots.

(a) General. (1) Purpose. The purpose

of this section is to limit the emissions

of particulate matter into the ambient air

from human activity on unpaved

parking lots, unpaved roads and vacant

lots.

(2) Applicability. The provisions of

this section shall apply to owners/

operators of unpaved roads, unpaved

parking lots and vacant lots and

responsible parties for weed abatement

on vacant lots in the Phoenix PM–10

nonattainment area. This section does

not apply to unpaved roads, unpaved

parking lots or vacant lots located on an

industrial facility, construction, or

earth-moving site that has an approved
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41351

permit issued by Maricopa County

Environmental Services Division under

Rule 200, Section 305, Rule 210 or Rule

220 containing a Dust Control Plan

approved under Rule 310 covering all

unpaved parking lots, unpaved roads

and vacant lots. This section does not

apply to the two Indian Reservations

(the Salt River Pima-Maricopa Indian

Community and the Fort McDowell

Mojave-Apache Indian Community) and

a portion of a third reservation (the Gila

River Indian Community) in the

Phoenix PM–10 nonattainment area.

Nothing in this definition shall preclude

applicability of this section to vacant

lots with disturbed surface areas due to

construction, earth-moving, weed

abatement or other dust generating

operations which have been terminated

for over eight months.

(3) The test methods described in

Appendix A of this section shall be used

when testing is necessary to determine

whether a surface has been stabilized as

defined in paragraph (b)(16) of this

section.

(b) Definitions. (1) Average daily trips

(ADT)—the average number of vehicles

that cross a given surface during a

specified 24-hour time period as

determined by the Institute of

Transportation Engineers Trip

Generation Report (6th edition, 1997) or

tube counts.

(2) Chemical/organic stabilizer—Any

non-toxic chemical or organic dust

suppressant other than water which

meets any specifications, criteria, or

tests required by any federal, state, or

local water agency and is not prohibited

for use by any applicable law, rule or

regulation.

(3) Disturbed surface area—Any

portion of the earth’s surface, or

materials placed thereon, which has

been physically moved, uncovered,

destabilized, or otherwise modified

from its undisturbed natural condition,

thereby increasing the potential for

emission of fugitive dust.

(4) Dust suppressants—Water,

hygroscopic materials, solution of water

and chemical surfactant, foam, or nontoxic chemical/ organic stabilizers not

prohibited for use by any applicable

law, rule or regulation, as a treatment

material to reduce fugitive dust

emissions.

(5) EPA—United States

Environmental Protection Agency,

Region IX, 75 Hawthorne Street, San

Francisco, California 94105.

(6) Fugitive dust—the particulate

matter entrained in the ambient air

which is caused from man-made and

natural activities such as, but not

limited to, movement of soil, vehicles,

equipment, blasting, and wind. This

excludes particulate matter emitted

directly from the exhaust of motor

vehicles and other internal combustion

engines, from portable brazing,

soldering, or welding equipment, and

from piledrivers.

(7) Lot—A parcel of land identified on

a final or parcel map recorded in the

office of the Maricopa County recorder

with a separate and distinct number or

letter.

(8) Low use unpaved parking lot—A

lot on which vehicles are parked no

more than thirty-five (35) days a year,

excluding days where the exemption in

paragraph (c)(2) of this section applies.

(9) Motor vehicle—A self-propelled

vehicle for use on the public roads and

highways of the State of Arizona and

required to be registered under the

Arizona State Uniform Motor Vehicle

Act, including any non-motorized

attachments, such as, but not limited to,

trailers or other conveyances which are

connected to or propelled by the actual

motorized portion of the vehicle.

(10) Off-road motor vehicle—any

wheeled vehicle which is used off

paved roadways and includes but is not

limited to the following:

(i) Any motor cycle or motor-driven

cycle;

(ii) Any motor vehicle commonly

referred to as a sand buggy, dune buggy,

or all terrain vehicle.

(11) Owner/operator—any person

who owns, leases, operates, controls,

maintains or supervises a fugitive dust

source subject to the requirements of

this section.

(12) Paving—Applying asphalt,

recycled asphalt, concrete, or asphaltic

concrete to a roadway surface.

(13) Phoenix PM–10 nonattainment

area—such area as defined in 40 CFR

81.303, excluding Apache Junction.

(14) PM–10—Particulate matter with

an aerodynamic diameter less than or

equal to a nominal 10 micrometers as

measured by reference or equivalent

methods that meet the requirements

specified for PM–10 in 40 CFR Part 50,

Appendix J.

(15) Reasonably available control

measures (RACM)—Techniques used to

prevent the emission and/or airborne

transport of fugitive dust and dirt.

(16) Stabilized surface—(i) Any

unpaved road or unpaved parking lot

surface in which any fugitive dust

plume emanating from vehicular

movement does not exceed 20 percent

opacity as determined in section I. of

Appendix A of this section.

(ii) Any vacant lot surface with:

(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. of

Appendix A of this section;

(B) A threshold friction velocity

(TFV), corrected for non-erodible

elements, of 100 cm/second or higher as

determined in section II.2 of Appendix

A of this section;

(C) Flat vegetation cover equal to at

least 50 percent as determined in

section II. 3. of Appendix A of this

section;

(D) Standing vegetation cover equal to

or greater than 30 percent as determined

in section II. 4. of Appendix A of this

section; or

(E) Standing vegetation cover equal to

or greater than 10 percent as determined

in section II.4. of Appendix A of this

section where threshold friction

velocity, corrected for non-erodible

elements, as determined in section II. 2

of Appendix A of this section is equal

to or greater than 43 cm/second.

(17) Unpaved Parking Lot—A

privately or publicly owned or operated

area utilized for parking vehicles that is

not paved and is not a Low Use

Unpaved Parking Lot.

(18) Unpaved Road—Any road,

equipment path, or driveway 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.

(19) Urban or Suburban Open Area—

An unsubdivided or undeveloped tract

of land adjoining a residential,

industrial or commercial area, located

on public or private property.

(20) Vacant Lot—A subdivided

residential, industrial, institutional,

governmental or commercial lot which

contains no approved or permitted

buildings or structures of a temporary or

permanent nature.

(c) Exemptions. The following

requirements in paragraph (d) of this

section do not apply:

(1) In paragraphs (d)(1) and (d)(3)(iii)

of this section: Any unpaved parking lot

or vacant lot 5,000 square feet or less.

(2) In paragraph (d)(1) of this section:

Any unpaved parking lot on any day in

which ten (10) or fewer vehicles enter.

(3) In paragraphs (d)(3)(i) and (d)(3)(ii)

of this section: Any vacant lot with less

than 0.50 acre (21,780 square feet) of

disturbed surface area(s).

(4) In paragraph (d) of this section:

Non-routine or emergency maintenance

of flood control channels and water

retention basins.

(5) In paragraph (d) of this section:

Vehicle test and development facilities

and operations when dust is required to

test and validate design integrity,

product quality and/or commercial

acceptance. Such facilities and
41352 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

operations shall be exempted from the

provisions of this section only if such

testing is not feasible within enclosed

facilities.

(6) In paragraph (d)(3)(i) of this

section: Weed abatement operations

performed on any vacant lot or property

under the order of a governing agency

for the control of a potential fire hazard

or otherwise unhealthy condition

provided that mowing, cutting, or

another similar process is used to

maintain weed stubble at least three (3)

inches above the soil surface. This

includes the application of herbicides

provided that the clean-up of any debris

does not disturb the soil surface.

(7) In paragraph (d)(3)(i) of this

section: Weed abatement operations that

receive an approved Earth Moving

permit under Maricopa County Rule

200, Section 305 (adopted 11/15/93).

(d) Requirements. (1) Unpaved

parking lots.

(i) Any owners/operators of an

unpaved parking lot shall implement

one of the following RACM on any

surface area(s) of the lot on which

vehicles enter and park.

(A) Pave; or

(B) Apply chemical/organic stabilizers

in sufficient concentration and

frequency to maintain a stabilized

surface; or

(C) Apply and maintain surface gravel

uniformly such that the surface is

stabilized.

(ii) Any owners/operators of a Low

Use Unpaved Parking Lot as defined in

paragraph (b)(8) of this section shall

implement one of the RACM under

paragraph (d)(1)(i) of this section on any

day(s) in which over 100 vehicles enter

the lot, such that the surface area(s) on

which vehicles enter and park is/are

stabilized throughout the duration of

time that vehicles are parked.

(2) Unpaved roads. Any owners/

operators of existing unpaved roads

with ADT volumes of 250 vehicles or

greater shall implement one of the

following RACM along the entire

surface of the road or road segment that

is located within the Phoenix nonattainment area by June 10, 2000:

(i) Pave; or

(ii) Apply chemical/organic stabilizers

in sufficient concentration and

frequency to maintain a stabilized

surface; or

(iii) Apply and maintain surface

gravel uniformly such that the surface is

stabilized.

(3) Vacant lots. The following

provisions shall be implemented as

applicable.

(i) Weed abatement. No person shall

remove vegetation from any vacant lot

by blading, disking, plowing under or

any other means without implementing

all of the following RACM to prevent or

minimize fugitive dust.

(A) Apply a dust suppressant(s) to the

total surface area subject to disturbance

immediately prior to or during the weed

abatement.

(B) Prevent or eliminate material

track-out onto paved surfaces and access

points adjoining paved surfaces.

(C) Apply a dust suppressant(s),

gravel, compaction or alternative control

measure immediately following weed

abatement to the entire disturbed

surface area such that the surface is

stabilized.

(ii) Disturbed surfaces. Any owners/

operators of an urban or suburban open

area vacant lot of which any portion has

a disturbed surface area(s) that remain(s)

unoccupied, unused, vacant or

undeveloped for more than fifteen (15)

calendar days shall implement one of

the following RACM within sixty (60)

calendar days following the disturbance.

(A) Establish ground cover vegetation

on all disturbed surface areas in

sufficient quantity to maintain a

stabilized surface; or

(B) Apply a dust suppressant(s) to all

disturbed surface areas in sufficient

quantity and frequency to maintain a

stabilized surface; or

(C) Restore to a natural state, i.e. as

existing in or produced by nature

without cultivation or artificial

influence, such that all disturbed

surface areas are stabilized; or

(D) Apply and maintain surface gravel

uniformly such that all disturbed

surface areas are stabilized.

(iii) Motor vehicle disturbances. Any

owners/operators of an urban or

suburban open area vacant lot of which

any portion has a disturbed surface area

due to motor vehicle or off-road motor

vehicle use or parking, notwithstanding

weed abatement operations or use or

parking by the owner(s), shall

implement one of the following RACM

within 60 calendar days following the

initial determination of disturbance.

(A) Prevent motor vehicle and offroad motor vehicle trespass/parking by

applying fencing, shrubs, trees, barriers

or other effective measures; or

(B) Apply and maintain surface gravel

or chemical/organic stabilizer uniformly

such that all disturbed surface areas are

stabilized.

(4) Alternative control measures. For

sources subject to requirements in

paragraphs (d)(1), (d)(2), (d)(3)(ii) and

(d)(3)(iii) of this section: As an

alternative to compliance, owners/

operators may use any other alternative

control measures approved by EPA

pursuant to paragraphs (e)(1) and (e)(2)

of this section as equivalent to the

methods specified in paragraph (d) of

this section.

(5) Implementation date of RACM. All

of the requirements in paragraph (d) of

this section shall be effective eight (8)

months from September 2, 1998. For

requirements in paragraph (d)(3)(ii) and

(d)(3)(iii) of this section, RACM shall be

implemented within eight (8) months

from September 2, 1998, or within 60

calendar days following the disturbance,

whichever is later.

(e) Administrative requirements. (1)

Proposed alternative control measures

for sources subject to paragraph (d)(2) of

this section must be submitted to EPA

for approval within one year from

September 2, 1998. Proposed alternative

control measures for sources subject to

paragraph (d)(1) of this section must be

submitted to EPA for approval within 90

calendar days prior to the required

RACM implementation date as specified

in this section. Proposed alternative

control measures for sources subject to

paragraphs (d)(3)(ii) and (d)(3)(iii) of

this section must be submitted to EPA

for approval within 90 calendar days

prior to the required RACM

implementation date as specified in this

section or within 60 calendar days

following the initial determination of

disturbance, whichever is later.

(2) Upon receipt of an alternative

control measure, EPA shall provide

written notice within 30 calendar days

to the owner/operator approving or

disapproving the alternative control

measure. Should EPA not provide

written notice of approval or

disapproval within the above deadline,

the owner/operator shall assume that

the alternative control measure is

approved. Upon receiving notice of EPA

approval, the owner/operator shall

implement the alternative control

measure according to the timeframe

established in this section unless

otherwise specified by EPA. Upon

receiving notice of EPA disapproval of

the alternative control measure, the

owner/operator shall implement RACM

according to the specifications and

timeframe established in this section.

For sources submitting an alternative

control measure under paragraphs

(d)(3)(ii) or (d)(3)(iii) of this section,

owners/operators shall implement the

alternative control measure if approved

by EPA within 60 calendar days upon

receiving written notice, or, upon

disapproval of the alternative control

measure, implement RACM as specified

in this section within 60 calendar days

upon receiving written notice.

(f) Monitoring and records. (1) Any

owners/operators that are subject to the

provisions of this section shall compile

and retain records that provide evidence
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41353

of control measure application,

indicating the type of treatment or

measure, extent of coverage and date

applied. For control measures involving

chemical/organic stabilization, records

shall also indicate the type of product

applied, vendor name, label instructions

for approved usage, and the method,

frequency, concentration and quantity

of application.

(2) Copies of control measure records

and dust control plans along with

supporting documentation shall be

retained for at least three years.

(3) Agency surveys. (i) EPA or other

appropriate entity shall conduct a

survey of the number and size (or

length) of unpaved roads, unpaved

parking lots, and vacant lots subject to

the provisions of this rule located

within the Phoenix PM–10

nonattainment area beginning no later

than 365 days from September 2, 1998.

(ii) EPA or other appropriate entity

shall conduct a survey at least every

three years within the Phoenix PM–10

nonattainment area beginning no later

than 365 days from September 2, 1998,

which includes:

(A) An estimate of the percentage of

unpaved roads, unpaved parking lots,

and vacant lots subject to this rule to

which RACM as required in this section

have been applied; and

(B) A description of the most

frequently applied RACM and estimates

of their control effectiveness.

Appendix A to § 52.128 Test Methods To

Determine Whether a Surface Is Stabilized

I. Unpaved Roads and Unpaved Parking Lots

Conduct opacity observations in

accordance with Reference Method 9 (40 CFR

Part 60, appendix A) and Methods 203A and

203C of this appendix, with opacity readings

taken at five second observation intervals and

two consecutive readings per plume

beginning with the first reading at zero

seconds, in accordance with Method 203C,

sections 2.3.2. and 2.4.2 of this appendix.

Conduct visible opacity tests only on dry

unpaved surfaces (i.e. when the surface is not

damp to the touch) and on days when

average wind speeds do not exceed 15 miles

per hour (mph).

Method 203A—Visual Determination of

Opacity of Emissions From Stationary

Sources for Time-Arranged Regulations

Method 203A is virtually identical to

EPA’s Method 9 of 40 CFR part 60, appendix

A except for the data-reduction procedures,

which provide for averaging times other than

6 minutes. That is, using Method 203A with

a 6-minute averaging time would be the same

as following EPA Method 9. Additionally,

Method 203A provides procedures for

fugitive dust applications. The certification

procedures provided in section 3 are

virtually identical to Method 9 and are

provided here, in full, for clarity and

convenience.

1. Applicability and Principle

1.1 Applicability. This method is

applicable for the determination of the

opacity of emissions from sources of visible

emissions for time-averaged regulations. A

time-averaged regulation is any regulation

that requires averaging visible emission data

to determine the opacity of visible emissions

over a specific time period.

1.2 Principle. The opacity of emissions

from sources of visible emissions is

determined visually by an observer qualified

according to the procedures of section 3.

2. Procedures

An observer qualified in accordance with

section 3 of this method shall use the

following procedures for visually

determining the opacity of emissions.

2.1 Procedures for Emissions from

Stationary Sources. These procedures are not

applicable to this section.

2.2 Procedures for Fugitive Process Dust

Emissions. These procedures are applicable

for the determination of the opacity of

fugitive emissions by a qualified observer.

The qualified field observer should do the

following:

2.2.1 Position. Stand at a position at least

5 meters from the fugitive dust source in

order to provide a clear view of the emissions

with the sun oriented in the 140-degree

sector to the back. Consistent as much as

possible with maintaining the above

requirements, make opacity observations

from a position such that the line of vision

is approximately perpendicular to the plume

and wind direction. As much as possible, if

multiple plumes are involved, do not include

more than one plume in the line of sight at

one time.

2.2.2 Field Records. Record the name of

the plant or site, fugitive source location,

source type [pile, stack industrial process

unit, incinerator, open burning operation

activity, material handling (transfer, loading,

sorting, etc.)], method of control used, if any,

observer’s name, certification data and

affiliation, and a sketch of the observer’s

position relative to the fugitive source. Also,

record the time, estimated distance to the

fugitive source location, approximate wind

direction, estimated wind speed, description

of the sky condition (presence and color of

clouds), observer’s position relative to the

fugitive source, and color of the plume and

type of background on the visible emission

observation form when opacity readings are

initiated and completed.

2.2.3 Observations. Make opacity

observations, to the extent possible, using a

contrasting background that is perpendicular

to the line of vision. For roads, storage piles,

and parking lots, make opacity observations

approximately 1 meter above the surface

from which the plume is generated. For other

fugitive sources, make opacity observations

at the point of greatest opacity in that portion

of the plume where condensed water vapor

is not present. For intermittent sources, the

initial observation should begin immediately

after a plume has been created above the

surface involved. Do not look continuously at

the plume but, instead, observe the plume

momentarily at 15-second intervals.

2.3 Recording Observations. Record the

opacity observations to the nearest 5 percent

every 15 seconds on an observational record

sheet. Each momentary observation recorded

represents the average opacity of emissions

for a 15-second period.

2.4 Data Reduction for Time-Averaged

Regulations. A set of observations is

composed of an appropriate number of

consecutive observations determined by the

averaging time specified. Divide the recorded

observations into sets of appropriate time

lengths for the specified averaging time. Sets

must consist of consecutive observations;

however, observations immediately

preceding and following interrupted

observations shall be deemed consecutive.

Sets need not be consecutive in time and in

no case shall two sets overlap, resulting in

multiple violations. For each set of

observations, calculate the appropriate

average opacity.

3. Qualification and Testing

3.1 Certification Requirements. To

receive certification as a qualified observer,

a candidate must be tested and demonstrate

the ability to assign opacity readings in 5

percent increments to 25 different black

plumes and 25 different white plumes, with

an error not to exceed 15 percent opacity on

any one reading and an average error not to

exceed 7.5 percent opacity in each category.

Candidates shall be tested according to the

procedures described in paragraph 3.2. Any

smoke generator used pursuant to paragraph

3.2 shall be equipped with a smoke meter

which meets the requirements of paragraph

3.3. Certification tests that do not meet the

requirements of paragraphs 3.2 and 3.3 are

not valid.

The certification shall be valid for a period

of 6 months, and after each 6-month period,

the qualification procedures must be

repeated by an observer in order to retain

certification.

3.2 Certification Procedure. The

certification test consists of showing the

candidate a complete run of 50 plumes, 25

black plumes and 25 white plumes,

generated by a smoke generator. Plumes shall

be presented in random order within each set

of 25 black and 25 white plumes. The

candidate assigns an opacity value to each

plume and records the observation on a

suitable form. At the completion of each run

of 50 readings, the score of the candidate is

determined. If a candidate fails to qualify, the

complete run of 50 readings must be repeated

in any retest. The smoke test may be

administered as part of a smoke school or

training program, and may be preceded by

training or familiarization runs of the smoke

generator during which candidates are shown

black and white plumes of known opacity.

3.3 Smoke Generator Specifications. Any

smoke generator used for the purpose of

paragraph 3.2 shall be equipped with a

smoke meter installed to measure opacity

across the diameter of the smoke generator

stack. The smoke meter output shall display

in-stack opacity, based upon a path length

equal to the stack exit diameter on a full 0

to 100 percent chart recorder scale. The

smoke meter optical design and performance

shall meet the specifications shown in Table

A of method 203C. The smoke meter shall be

calibrated as prescribed in paragraph 3.3.1

prior to conducting each smoke reading test.
41354 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

At the completion of each test, the zero and

span drift shall be checked, and if the drift

exceeds ±1 percent opacity, the condition

shall be corrected prior to conducting any

subsequent test runs. The smoke meter shall

be demonstrated at the time of installation to

meet the specifications listed in Table A of

method 203C. This demonstration shall be

repeated following any subsequent repair or

replacement of the photocell or associated

electronic circuitry including the chart

recorder or output meter, or every 6 months,

whichever occurs first.

3.3.1 Calibration. The smoke meter is

calibrated after allowing a minimum of 30

minutes warm-up by alternately producing

simulated opacity of 0 percent and 100

percent. When stable response at 0 percent or

100 percent is noted, the smoke meter is

adjusted to produce an output of 0 percent

or 100 percent, as appropriate. This

calibration shall be repeated until stable 0

percent and 100 percent readings are

produced without adjustment. Simulated 0

percent and 100 percent opacity values may

be produced by alternately switching the

power to the light source on and off while

the smoke generator is not producing smoke.

3.3.2 Smoke Meter Evaluation. The

smoke meter design and performance are to

be evaluated as follows:

3.3.2.1 Light Source. Verify from

manufacturer’s data and from voltage

measurements made at the lamp, as installed,

that the lamp is operated within ±5 percent

of the nominal rated voltage.

3.3.2.2 Spectral Response of Photocell.

Verify from manufacturer’s data that the

photocell has a photopic response; i.e., the

spectral sensitivity of the cell shall closely

approximate the standard spectral-luminosity

curve for photopic vision which is referenced

in (b) of Table A of method 203C.

3.3.2.3 Angle of View. Check

construction geometry to ensure that the total

angle of view of the smoke plume, as seen

by the photocell, does not exceed 15 degrees.

Calculate the total angle of view as follows:

φ

v = 2 tan¥1 d/2L,

Where:

φ

v = total angle of view;

d = the photocell diameter + the diameter of

the limiting aperture; and

L = distance from the photocell to the

limiting aperture.

The limiting aperture is the point in the

path between the photocell and the smoke

plume where the angle of view is most

restricted. In smoke generator smoke meters,

this is normally an orifice plate.

3.3.2.4 Angle of Projection. Check

construction geometry to ensure that the total

angle of projection of the lamp on the smoke

plume does not exceed 15 degrees. Calculate

the total angle of projection as follows:

φ

p = 2 tan¥1 d/2L

Where:

φ

p = total angle of projection;

d = the sum of the length of the lamp

filament + the diameter of the limiting

aperture; and

L = the distance from the lamp to the limiting

aperture.

3.3.2.5 Calibration Error. Using neutraldensity filters of known opacity, check the

error between the actual response and the

theoretical linear response of the smoke

meter. This check is accomplished by first

calibrating the smoke meter according to

3.3.1 and then inserting a series of three

neutral-density filters of nominal opacity of

20, 50, and 75 percent in the smoke meter

path length. Use filters calibrated within ±2

percent. Care should be taken when inserting

the filters to prevent stray light from affecting

the meter. Make a total of five

nonconsecutive readings for each filter. The

maximum opacity error on any one reading

shall be ±3 percent.

3.3.2.6 Zero and Span Drift. Determine

the zero and span drift by calibrating and

operating the smoke generator in a normal

manner over a 1-hour period. The drift is

measured by checking the zero and span at

the end of this period.

3.3.2.7 Response Time. Determine the

response time by producing the series of five

simulated 0 percent and 100 percent opacity

values and observing the time required to

reach stable response. Opacity values of 0

percent and 100 percent may be simulated by

alternately switching the power to the light

source off and on while the smoke generator

is not operating.

4. References

1. U. S. Environmental Protection Agency.

Standards of Performance for New

Stationary Sources; appendix A; Method

9 for Visual Determination of the Opacity

of Emissions from Stationary Sources.

Final Rule. 39 FR 219. Washington, DC.

U. S. Government Printing Office.

November 12, 1974.

2. Office of Air and Radiation. ‘‘Quality

Assurance Guideline for Visible

Emission Training Programs.’’ EPA–600/

S4–83–011. Quality Assurance Division.

Research Triangle Park, N.C. May 1982.

3. ‘‘Method 9—Visible Determination of the

Opacity of Emissions from Stationary

Sources.’’ February 1984. Quality

Assurance Handbook for Air Pollution

Measurement Systems. Volume III,

section 3.1.2. Stationary Source Specific

Methods. EPA–600–4–77–027b. August

1977. Office of Research and

Development Publications, 26 West Clair

Street, Cincinnati, OH.

4. Office of Air Quality Planning and

Standards. ‘‘Opacity Error for Averaging

and Nonaveraging Data Reduction and

Reporting Techniques.’’ Final ReportSR–1–6–85. Emission Measurement

Branch, Research Triangle Park, N.C.

June 1985.

5. The U. S. Environmental Protection

Agency. Preparation, Adoption, and

Submittal of State Implementation Plans.

Methods for Measurement of PM10

Emissions from Stationary Sources. Final

Rule. Federal Register. Washington, DC.

U. S. Government Printing Office.

Volumes 55. No. 74. pps. 14246–14279.

April 17, 1990.

Method 203C—Visual Determination of

Opacity of Emissions From Stationary

Sources for Instantaneous Limitation

Regulations

Method 203C is virtually identical to EPA’s

Method 9 of appendix A to 40 CFR part 60,

except for the data-reduction procedures

which have been modified for application to

instantaneous limitation regulations.

Additionally, Method 203C provides

procedures for fugitive dust applications

which were unavailable when Method 9 was

promulgated. The certification procedures in

section 3 are identical to Method 9. These

certification procedures are provided in

Method 203A as well, and, therefore, have

not been repeated in this method.

1. Applicability and Principle

1.1 Applicability. This method is

applicable for the determination of the

opacity of emissions from sources of visible

emissions for instantaneous limitations. An

instantaneous limitation regulation is an

opacity limit which is never to be exceeded.

1.2 Principle. The opacity of emissions

from sources of visible emissions is

determined visually by a qualified observer.

2. Procedures

The observer qualified in accordance with

section 3 of this method shall use the

following procedures for visually

determining the opacity of emissions.

2.1 Procedures for Emissions From

Stationary Sources. Same as 2.1, Method

203A.

2.1.1 Position. Same as 2.1.1, Method

203A.

2.1.2 Field Records. Same as 2.1.2,

Method 203A.

2.1.3 Observations. Make opacity

observations at the point of greatest opacity

in that portion of the plume where

condensed water vapor is not present.

Do not look continuously at the

plume. Instead, observe the plume

momentarily at the interval specified in

the subject regulation. Unless otherwise

specified, a 15-second observation

interval is assumed.

2.1.3.1 Attached Steam Plumes. Same as

2.1.3.1, Method 203A.

2.1.3.2 Detached Steam Plumes. Same as

2.1.3.2, Method 203A.

2.2 Procedures for Fugitive Process Dust

Emissions.

2.2.1 Position. Same as section 2.2.1,

Method 203A.

2.2.2 Field Records. Same as section

2.2.2, Method 203A.

2.2.3 Observations.

2.2.3.1 Observations for a 15-second

Observation Interval Regulations. Same as

section 2.2.3, Method 203A.

2.2.3.2 Observations for a 5-second

Observation Interval Regulations. Same as

section 2.2.3, Method 203A, except, observe

the plume momentarily at 5-second intervals.

2.3 Recording Observations. Record

opacity observations to the nearest 5 percent

at the prescribed interval on an observational

record sheet. Each momentary observation

recorded represents the average of emissions

for the prescribed period. If a 5-second

observation period is not specified in the

applicable regulation, a 15-second interval is

assumed. The overall time for which

recordings are made shall be of a length

appropriate to the regulation for which

opacity is being measured.

2.3.1 Recording Observations for 15-

second Observation Interval Regulations.
Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations 41355

Record opacity observations to the nearest 5

percent at 15-second intervals on an

observational record sheet. Each momentary

observation recorded represents the average

of emissions for a 15-second period.

2.3.2 Recording Observations for 5-

second Observation Interval Regulations.

Record opacity observations to the nearest 5

percent at 5-second intervals on an

observational record sheet. Each momentary

observation recorded represents the average

of emissions for 5-second period.

2.4 Data Reduction for Instantaneous

Limitation Regulations. For an instantaneous

limitation regulation, a 1-minute averaging

time will be used. Divide the observations

recorded on the record sheet into sets of

consecutive observations. A set is composed

of the consecutive observations made in 1

minute. Sets need not be consecutive in time,

and in no case shall two sets overlap. Reduce

opacity observations by dividing the sum of

all observations recorded in a set by the

number of observations recorded in each set.

2.4.1 Data Reduction for 15-second

Observation Intervals. Reduce opacity

observations by averaging four consecutive

observations recorded at 15-second intervals.

Divide the observations recorded on the

record sheet into sets of four consecutive

observations. For each set of four

observations, calculate the average by

summing the opacity of the four observations

and dividing this sum by four.

2.4.2 Data Reduction for 5-second

Observation Intervals. Reduce opacity

observations by averaging 12 consecutive

observations recorded at 5-second intervals.

Divide the observations recorded on the

record sheet into sets of 12 consecutive

observations. For each set of 12 observations,

calculate the average by summing the opacity

of the 12 observations and dividing this sum

by 12.

3. Qualification and Test

Same as section 3, Method 203A.

TABLE A.—SMOKE METER DESIGN

AND PERFORMANCE SPECIFICATIONS

Parameter Specification

a. Light Source .......... Incandescent lamp

operated at nominal rated voltage.

b. Spectral response

of photocell.

Photopic (daylight

spectral response

of the human eye—

Reference 4.1 of

section 4.).

c. Angle of view ......... 15 degrees maximum

total angle.

d. Angle of projection 15 degrees maximum

total angle.

e. Calibration error .... ±+3-percent opacity,

maximum.

f. Zero and span drift ±1-percent opacity,

30 minutes.

g. Response time ...... ≤ 5 seconds.

II. Vacant Lots

The following test methods shall be used

for determining whether a vacant lot, or

portion thereof, has a stabilized surface.

Should a disturbed vacant lot contain more

than one type of disturbance, soil, vegetation

or other characteristics which are visibly

distinguishable, test each representative

surface for stability separately in random

areas according to the test methods in section

II. of this appendix and include or eliminate

it from the total size assessment of disturbed

surface area(s) depending upon test method

results. A vacant lot surface shall be

considered stabilized if any of the test

methods in section II. of this appendix

indicate that the surface is stabilized such

that the conditions defined in paragraph

(b)(16)(ii) of this section are met:

1. Determination of visible crust thickness

Where a visible crust exists, break off a

small piece of crust. Check whether it

crumbles easily between the fingers. Using a

ruler, measure the thickness of the crust.

Determination of thickness shall be based on

at least three (3) crustal measurements

representative of the disturbed surface area.

If thin deposits of loose uncombined grains

cover more than 50 percent of a crusted

surface, apply the test method in section II.2.

of this appendix to the loose material to

determine whether the surface is stabilized.

2. Determination of Threshold Friction

Velocity (TFV)

For disturbed surface areas that are not

crusted or vegetated, determine threshold

friction velocity (TFV) according to the

following sieving field procedure (based on

a 1952 laboratory procedure published by W.

S. Chepil).

(i) Obtain and stack a set of sieves with the

following openings: 4 millimeters (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. Collect a sample of

loose surface material from an area at least

30 cm by 30 cm in size to a depth of

approximately 1 cm using a brush and

dustpan or other similar device. Only collect

soil samples from dry surfaces (i.e. when the

surface is not damp to the touch). Remove

any rocks larger than 1 cm in diameter from

the sample. Pour the sample into the top

sieve (4 mm opening) and cover the sieve/

collector pan unit with a lid. Minimize

escape of particles into the air when

transferring surface soil into the sieve/

collector pan unit. Move the covered sieve/

collector pan unit by hand using a broad,

circular arm motion in the horizontal plane.

Complete twenty circular arm movements,

ten clockwise and ten counterclockwise, at a

speed just necessary to achieve some relative

horizontal motion between the sieves and the

particles. 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

loose particles. If loose particles have not

been sifted to the finest sieve through which

they can pass, reassemble and cover the

sieve/collector pan unit and gently rotate it

an additional ten times. After disassembling

the sieve/collector pan unit, slightly tilt and

gently tap each sieve and the collector pan

so that material aligns along one side. In

doing so, minimize escape of particles into

the air. Line up the sieves and collector pan

in a row and visibly inspect the relative

quantities of catch in order to determine

which sieve (or whether the collector pan)

contains the greatest volume of material. If a

visual determination of relative volumes of

catch among sieves is difficult, use a

graduated cylinder to measure the volume.

Estimate TFV for the sieve catch with the

greatest volume using Table 1, which

provides a correlation between sieve opening

size and TFV.

TABLE 1.—(METRIC UNITS). DETERMINATION OF THRESHOLD FRICTION

VELOCITY (TFV)

Tyler Sieve No. Opening

(mm)

TFV

(cm/s)

5 .............................. 4 ≤100

9 .............................. 2 100

16 ............................ 1 76

32 ............................ 0.5 58

60 ............................ 0.25 43

Collector Pan .......... .................. 30

Collect at least three (3) soil samples which

are representative of the disturbed surface

area, repeat the above TFV test method for

each sample and average the resulting TFVs

together to determine the TFV uncorrected

for non-erodible elements.

(ii) Non-erodible elements are distinct

elements on the disturbed surface area that

are larger than one (1) cm in diameter,

remain firmly in place during a wind episode

and inhibit soil loss by consuming part of the

shear stress of the wind. Non-erodible

elements include stones and bulk surface

material but do not include flat or standing

vegetation. For surfaces with non-erodible

elements, determine corrections to the TFV

by identifying the fraction of the survey area,

as viewed from directly overhead, that is

occupied by non-erodible elements using the

following procedure. Select a survey area of

one (1) meter by 1 meter. Where many nonerodible elements lie on the disturbed surface

area, separate them into groups according to

size. For each group, calculate the overhead

area for the non-erodible elements according

to the following equations:

(Average length) × (Average width) = Average Dimensions ...................................................................................................................... Eq. 1

(Average Dimensions) × (Number of Elements) = Overhead Area ............................................................................................................ Eq. 2

Overhead Area of Group 1 + Overhead Area of Group 2 (etc..) = Total Overhead Area ........................................................................ Eq. 3

Total Overhead Area/2 = Total Frontal Area ............................................................................................................................................. Eq. 4
41356 Federal Register / Vol. 63, No. 148 / Monday, August 3, 1998 /Rules and Regulations

(Total Frontal Area/Survey Area) × 100 = Percent Cover of Non-erodible Elements .............................................................................. Eq. 5

(Ensure consistent units of measurement, e.g.

square meters or square inches when

calculating percent cover.)

Repeat this procedure on an additional two

(2) distinct survey areas representing a

disturbed surface and average the results. Use

Table 2 to identify the correction factor for

the percent cover of non-erodible elements.

Multiply the TFV by the corresponding

correction factor to calculate the TFV

corrected for non-erodible elements.

TABLE 2.—CORRECTION FACTORS FOR

THRESHOLD FRICTION VELOCITY

Percent cover of non-erodible elements

Correction

factor

≥ 10% ............................................... 5

≥ 5% and < 10% .............................. 3

< 5% and ≥ 1% ................................ 2

< 1% ................................................. None.

3. Determination of Flat Vegetation Cover

Flat vegetation includes attached (rooted)

vegetation or unattached vegetative debris

lying on the surface with a predominant

horizontal orientation that is not subject to

movement by wind. Flat vegetation which is

dead but firmly attached shall be considered

equally protective as live vegetation. Stones

or other aggregate larger than one centimeter

in diameter shall be considered protective

cover in the course of conducting the line

transect method. Where flat vegetation exists,

conduct the following line transect method.

(i) Stretch a one-hundred (100) foot

measuring tape across a disturbed surface

area. Firmly anchor both ends of the

measuring tape into the surface using a tool

such as a screwdriver with the tape stretched

taut and close to the soil surface. If vegetation

exists in regular rows, place the tape

diagonally (at approximately a 45 degree

angle) away from a parallel or perpendicular

position to the vegetated rows. Pinpoint an

area the size of a 3⁄32 inch diameter brazing

rod or wooden dowel centered above each

one-foot interval mark along one edge of the

tape. Count the number of times that flat

vegetation lies directly underneath the

pinpointed area at one-foot intervals.

Consistently observe the underlying surface

from a 90 degree angle directly above each

pinpoint on one side of the tape. Do not

count the underlying surface as vegetated if

any portion of the pinpoint extends beyond

the edge of the vegetation underneath in any

direction. If clumps of vegetation or

vegetative debris lie underneath the

pinpointed area, count the surface as

vegetated unless bare soil is visible directly

below the pinpointed area. When 100

observations have been made, add together

the number of times a surface was counted

as vegetated. This total represents the percent

of flat vegetation cover (e.g. if 35 positive

counts were made, then vegetation cover is

35 percent). If the disturbed surface area is

too small for 100 observations, make as many

observations as possible. Then multiply the

count of vegetated surface areas by the

appropriate conversion factor to obtain

percent cover. For example, if vegetation was

counted 20 times within a total of 50

observations, divide 20 by 50 and multiply

by 100 to obtain a flat vegetation cover of 40

percent.

(ii) Conduct the above line transect test

method an additional two (2) times on areas

representative of the disturbed surface and

average results.

4. Determination of Standing Vegetation

Cover

Standing vegetation includes vegetation

that is attached (rooted) with a predominant

vertical orientation. Standing vegetation

which is dead but firmly rooted shall be

considered equally protective as live

vegetation. Conduct the following standing

vegetation test method to determine if 30

percent cover or more exists. If the resulting

percent cover is less than 30 percent but

equal to or greater than 10 percent, then

conduct the Threshold Friction Velocity test

in Section II.2. of this in order to determine

whether the disturbed surface area is

stabilized according to paragraph

(b)(16)(ii)(E) of this section.

(i) For standing vegetation that consists of

large, separate vegetative structures (for

example, shrubs and sagebrush), select a

survey area representing the disturbed

surface that is the shape of a square with

sides equal to at least ten (10) times the

average height of the vegetative structures.

For smaller standing vegetation, select a

survey area of three (3) feet by 3 feet.

(ii) Count the number of standing

vegetative structures within the survey area.

Count vegetation which grows in clumps as

a single unit. Where vegetation of different

height and width exists, count it in groups

with similar dimensions within the survey

area. For each group, calculate the frontal

silhouette area for the vegetative structures

according to the following equations:

(Average height) × (Average width) = Average Dimensions Eq. 6

(Average Dimensions) × (Number of Vegetation) = Frontal Silhouette Area 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) × 100 = Percent Cover of Standing Vegetation Eq. 9

(Ensure consistent units of measurement, e.g.

square meters or square inches when

calculating percent cover.)

(iii) Within a disturbed surface area that

contains multiple types of vegetation with

each vegetation type uniformly distributed,

results of the percent cover associated with

the individual vegetation types may be added

together.

(iv) Repeat this procedure on an additional

two (2) distinct survey areas representing the

disturbed surface and average the results.

5. Alternative Test Methods

Alternative test methods may be used upon

obtaining the written approval of the EPA.

[FR Doc. 98–20147 Filed 7–31–98; 8:45 am]

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