Enhanced Monitoring Program

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 51, 52, 60, 61 and 64

[FRL-5128-3]

Enhanced Monitoring Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule; reopening of public comment period.

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SUMMARY: EPA is soliciting comment on a limited set of revisions to its

proposed Enhanced Monitoring Program. EPA received numerous comments on

a wide range of issues pertaining to the October 22, 1993 proposed

rulemaking for a new 40 CFR part 64. EPA is issuing this notice to take

additional comment on a limited number of specific issues concerning

the proposed regulations. First, the Agency is considering phasing in

the implementation of the program over a five year period. This

implementation approach would allow for the Agency to develop guidance

on acceptable enhanced monitoring protocols for many types of affected

emissions units in order to streamline the selection and approval of

enhanced monitoring. Second, EPA seeks comment on the consideration of

cost in selecting and approving enhanced monitoring protocols. Third,

the Agency seeks comment on a second phase of applicability for

nonattainment areas and on specifically adopting periodic monitoring

under 40 CFR part 70 as sufficient enhanced monitoring for applicable

emissions units that do not meet the emission level applicability

thresholds for part 64 enhanced monitoring. The range of issues on

which EPA is soliciting comment is strictly limited to those issues

identified in this notice.

DATES: Comments on the issues discussed in this notice must be received

by January 27, 1995.

ADDRESSES: Comments: Comments must be mailed (in duplicate, if

possible) to: EPA Air Docket (LE-131), Attention: Docket No. A-91-52,

Room M-1500, Waterside Mall, 401 M Street SW., Washington, DC 20460.

Comments should refer to page numbers and columns whenever possible.

Only comments addressing the specific issues identified below will be

considered.

Docket: Supporting information used in developing the regulations

is contained in Docket No. A-91-52. This docket is available for public

inspection and copying between 8 a.m. and 5:30 p.m. Monday through

Friday, excluding government holidays, and is located at: EPA Air

Docket (LE-131), Room M-1500, Waterside Mall, 401 M Street SW.,

Washington, DC 20460. A reasonable fee may be charged for copying.

FOR FURTHER INFORMATION CONTACT: Scott Throwe, U.S. Environmental

Protection Agency, Office of Enforcement and Compliance Assurance,

Manufacturing, Energy and Transportation Division, at (202) 564-7013.

SUPPLEMENTARY INFORMATION:

I. Purpose of Today's Notice

EPA received numerous comments on many issues in response to the

October 22, 1993 proposal to adopt an Enhanced Monitoring Program. The

EPA has reviewed those comments, and has engaged in a series of

discussions with a wide range of members of the public, including State

and local governments, affected industries, and environmental groups.

(Summaries of those discussions are contained in Docket No. A-91-52.)

Based on EPA's review of the written comments received, and in light of

the views presented by the parties noted above, EPA has determined that

it would be appropriate to reopen the comment period to solicit

additional comments on a limited number of issues. The EPA is

soliciting comment on the following issues: phasing in the

implementation of the Enhanced Monitoring Program over a five year

period, including a process for developing guidance on example

protocols and an implementation deadline that together would establish

the timing for phasing in the program; the consideration of cost in

proposing and approving enhanced monitoring protocols; a second phase

of applicability in nonattainment areas; and the adoption of periodic

monitoring under 40 CFR part 70 as sufficiently enhanced monitoring for

applicable emissions units that do not meet the emissions level

applicability thresholds for part 64 enhanced monitoring. The Agency

believes it is useful to reopen the comment period in this limited

manner in order to be certain that EPA has the benefit of a full range

of views on these topics.

This rulemaking is subject to a court-ordered deadline established

by a consent decree in Sierra Club v. Browner, No. 93-0124 (NHJ)

(D.D.C.). The original September 30, 1994 deadline for completion of

this rulemaking was extended by the court at the request of the parties

to December 20, 1994. The parties have agreed to request that the court

extend the deadline again, to April 30, 1995 in order to accommodate

this limited revision to the original rulemaking proposal and reopening

of the comment period. The EPA believes that most of the issues

addressed in the October 22, 1993 proposal have been fully addressed in

the numerous detailed comments already received. For this reason, and

in order to meet the court-ordered deadline and ensure that the

Enhanced Monitoring Program is promulgated without undue delay, the

scope of issues addressed in this notice is limited. The Agency will

not consider comments submitted on issues that are not related

specifically to those addressed in this notice. The issues on which EPA

is soliciting comment are set forth below.

II. Implementation

The proposed regulations would require that the owner or operator

of a major stationary source propose an enhanced monitoring protocol as

part of an application for a permit under the operating permits program

pursuant to title V of the Act. In the public comments received on the

proposed regulations, many commenters expressed concern about the

burden of the enhanced monitoring protocol selection process on the

operating permits program process. Many commenters suggested modifying

the implementation approach to address their concerns regarding burdens

associated with the permit process. Some commenters suggested that EPA

engage in rulemaking to determine nationally applicable enhanced

monitoring protocols for each source category as opposed to a permit-

based implementation approach. Others suggested separating the protocol

approval process from the permit approval process. Finally, still other

commenters suggested phasing in the implementation so that permitting

authorities would not be required to implement the entire enhanced

monitoring program in the first round of permits without the benefit of

national guidance on example enhanced monitoring protocols.

Because of the concerns about burdens to the permit process, EPA is

considering phasing in implementation of the enhanced monitoring rule

over a five year period. The implementation approach would have several

elements. First, EPA would develop guidance on presumptively acceptable

protocols that may be used for particular process/pollutant

combinations. In referring to ``process/pollutant combinations,'' the

Agency is referring to emissions units classified on both a pollutant-

specific basis and on a process-specific basis, including the

applicable pollutant control measures, and, where appropriate, the

nature of the emission limitation or standard. For example, one

process/pollutant combination could be SO2 emissions from a coal-fired

boiler using a scrubber to achieve compliance with an SO2 standard

expressed in lbs/mmBtu, while another could be a similar boiler using

low sulfur coal to achieve compliance with a sulfur-in-fuel limit.

After EPA issues guidance for a particular process/pollutant

combination, the owner or operator of an affected source that includes

such a combination for an emissions unit subject to part 64 would be

required to propose an enhanced monitoring protocol as part of the

operating permit application for the applicable emissions unit. Except,

as discussed below, sources generally would not be required under part

64 to propose a protocol in the absence of EPA guidance. The protocol

may be based on a presumptively acceptable example protocol developed

by EPA or a different monitoring approach that can satisfy the part 64

criteria. If the permitting authority has published a notice requesting

public comment on a draft title V permit before EPA issues applicable

guidance for a particular process/pollutant combination, then an

enhanced monitoring protocol would not have to be proposed for that

emissions unit until either a reopening of the permit that involves

public notice and comment, or the next renewal of the permit.

Finally, to ensure timely implementation of the program, EPA would

incorporate a ``hammer'' provision that would be triggered on January

1, 2000. Under this provision, any title V operating permit issued

after the effective date of the ``hammer'' provision would have to

include enhanced monitoring for emissions units subject to part 64. In

addition, any existing permit that does not include an enhanced

monitoring protocol where one would have been required by part 64 in

the absence of phased implementation would have to be reopened

expeditiously to incorporate enhanced monitoring. This ``hammer''

provision would apply regardless of whether EPA has issued guidance for

a particular process/pollutant combination.

Nothing in this phased approach would prevent a State from

requiring that enhanced monitoring comporting with the part 64 criteria

be included in a title V operating permit at any time before EPA's

guidance for the relevant pollutant/process combination is available.

The following outline describes in more detail each of these

particular elements of EPA's suggested implementation approach. The

Agency believes that its suggested approach alleviates many of the

burdens associated with trying to implement enhanced monitoring in the

first round of operating permits. The Agency's guidance development

process would serve as a means of assisting sources and permitting

authorities alike in implementing the program. At the same time, this

approach would assure that enhanced monitoring is adopted in a timely

manner at all affected emissions units. The EPA requests specific

comment on this suggested approach to phasing in the program. The

Agency solicits suggestions on any variations on this approach that

commenters believe would reduce burdens on the permitting process while

assuring timely adoption of enhanced monitoring protocols at affected

emissions units.

A. Guidance Development Process

As discussed in the preamble to the proposed rule (see 58 FR

54658), EPA is preparing an Enhanced Monitoring Reference Document that

will serve as guidance on the implementation of the Enhanced Monitoring

Program and that will include example protocols that can be used by

various types of emissions units with respect to specific process/

pollutant combinations. The Agency noted in the preamble to the

proposed rule that EPA intended this document to be a compendium of

available monitoring that would be updated on a regular basis.

Under the implementation approach described in this notice, the

purpose of the Enhanced Monitoring Reference Document would change in

some important respects. First, EPA would issue guidance for a given

process/pollutant combination only after a notice of availability of

the example protocol in draft form is published in the Federal

Register, with an opportunity for the public to respond in writing. The

Agency would commit to publishing example protocols for a wide variety

of process/pollutant combinations over the next four years, with many

examples scheduled to be completed by the end of 1995. In addition, the

examples published in the Enhanced Monitoring Reference Document would

serve as presumptively acceptable protocols for the type of process/

pollutant combinations covered by the individual protocols.

This approach would allow owners or operators and permitting

authorities to rely on the examples in the Enhanced Monitoring

Reference Document to a greater extent than contemplated in the

preamble to the proposed rule. However, the Agency notes that the

guidance is intended to remain as guidance, and would not be a binding

regulation. Thus, owners or operators would not be required to use

these example protocols where an alternative protocol would satisfy the

part 64 criteria. The Agency emphasizes that the flexibility in the

proposed rule to propose other monitoring satisfying the criteria in

the rule would be retained.

The Agency intends to develop presumptively acceptable protocols in

a manner that assures the broadest coverage of process/pollutant

combinations as expeditiously as possible while providing interested

parties the opportunity for input. One issue on which the Agency is

soliciting comment is the prioritization for developing example

protocols, including how to group example protocols to allow cost-

effective collection of supporting data and other technical background

information while at the same time ensuring that the most

environmentally significant protocols are completed expeditiously.

The Agency also solicits comment on whether and how to use

particular types of tools for evaluating the degree of confidence that

a particular monitoring methodology can provide in demonstrating

compliance. In particular, the Agency is considering a ``Data Quality

Objectives'' (DQO) process for protocol evaluation where EPA guidance

is not available or in circumstances in which a source proposes an

alternative to EPA's example protocol, although a DQO process may also

be helpful to EPA in developing its example protocols. (Item No. IV-A-3

in the docket for this rulemaking provides a detailed description of

this process.) Recognizing that all measurements have imprecisions, EPA

staff have developed the DQO process for application to environmental

data collection programs. The DQO process is a systematic method for

designing and evaluating any data collection activity, including the

development and evaluation of many types of enhanced monitoring

protocols. The process can account for the effects of process or

emissions variability, margin of compliance, measurement precision, and

frequency of data collection or measurements in designing an enhanced

monitoring protocol. The DQO procedure is very similar to other

statistical procedures used in the manufacturing and chemical process

industries to optimize equipment design and production operations.

The application of the DQO process to protocol development and

review would reduce uncertainty about whether a proposed protocol will

be accepted and will promote consistent decisions on review of

protocols. Application of the DQO process requires the establishment of

an acceptable level of probability of compliance assurance that

enhanced monitoring data must meet when the affected emissions unit is

emitting near or over the applicable emission limit. The appropriate

level for the probability limit is an issue for which the Agency

requests comment. The probability level selected will necessarily

affect protocol design. For example, a low probability of error (e.g.,

less than 5 percent) may dictate more frequent, and thus, costly,

sampling than a higher probability (e.g., 10 percent or higher). In

another example, the probability level selection may be linked to the

risk associated with a particular emission, that is, a lower

probability may be applied for higher risk emissions monitoring systems

data. The data needed to calculate these probabilities can be obtained

through field tests, historical data, quality assurance/quality control

documentation (e.g., measurement method precision), data from tests at

similar sources, or engineering and scientific literature.

In return, the DQO process would provide the owner or operator and

the permitting authority a method for evaluating enhanced monitoring

protocol design effectiveness. It also would allow for significant

flexibility in protocol design regarding which parameters should be

monitored, frequency of data collection, and margin of compliance. The

result should be cost-effective protocols that meet the data quality

criteria in part 64.

The DQO process would provide an iterative planning method for the

design of the enhanced monitoring protocol. The process leads to a

mathematical determination of the probability of decision errors

associated with reported protocol values. The DQO process might also

optimize the protocol design process by identifying the most effective

data collection and analysis design for the protocol that will satisfy

the DQOs. This element of the process may include additional data

collection on alternative protocol designs, formulating additional

mathematical expressions, or redefining the sample size or measurement

frequency.

With respect to this DQO process, the Agency requests specific

comment on three issues: (1) the usefulness or limitations of the DQO

approach to protocol design; (2) the acceptable probability level of

data quality or compliance assurance, and appropriate mathematical

approaches for determining the probability; and (3) examples of cost-

effective protocols demonstrating a known high level of assurance of

continuous compliance using DQO analysis principles.

The Agency also requests comment on the possibility of using

independent third parties to evaluate protocols proposed by sources

particularly where a source proposes an alternative to a presumptively

acceptable example protocol provided by EPA. The use of third parties

could increase confidence in the protocol development and review

process and reduce the resource burdens associated with enhanced

monitoring protocol review and approval. The Agency is considering the

idea of using third-party reviewers through a public/private

partnership between the Agency and interested industrial organizations.

The Agency has in the past relied on outside parties to streamline

implementation of programs, such as certifying laboratories in

connection with the certification of woodstoves with NSPS requirements

under 40 CFR part 60, subpart AAA. The function of the third party

organization would be to review industry-submitted protocols for a fee

paid by the source owner submitting the protocol for review. The third

party would provide to the source owner or operators and the permitting

authorities an evaluation of the feasibility and acceptability of the

protocol for specific applications. The Agency is soliciting comment on

whether establishing a third party review process to augment permitting

authority review and evaluation of protocols is appropriate; what would

be a suitable structure for a third party review organization and

process; the suitability of the industry paid fee for the third party

review services or any alternative funding mechanism; and what

procedures (e.g., data quality objectives analysis) would be

appropriate to guide a third party review.

The Agency intends to provide for input from all interested parties

throughout the example protocol guidance development process. To assure

that all interested parties have an opportunity to comment, EPA intends

to publish in the Federal Register a notice of availability of example

protocols in draft form prior to incorporating those protocols into the

Reference Document A notice of availability of final example protocols

would also be published in the Federal Register. In addition, the

Agency will use its Technology Transfer Network (TTN) electronic

bulletin board to facilitate public involvement in the development and

review of guidance on example protocols. The Agency will make available

through the TTN initial information on the development of example

protocol guidance, as well as draft and final example protocols and

other pertinent information. Regular updates to the Enhanced Monitoring

Reference Document will be available on the TTN as well. The Agency

anticipates updating the Enhanced Monitoring Reference Document after

the five year phase-in period, as well as throughout the initial

implementation period, so that it continues to reflect advances in

monitoring techniques. The phone number for accessing the TTN is (919)

541-5742. Persons unfamiliar with the TTN but interested in using the

system should contact the TTN help desk at (919) 541-5384 for further

information.

B. Timing of Implementation

Under the proposed rule, owners or operators would be required to

submit proposed enhanced monitoring protocols with an application for a

title V operating permit. The approach that EPA is now considering

would delay implementation until EPA has published a notice of

availability of an example protocol (or protocols) for the type of

process/pollutant combination for which a protocol is required, subject

to the ``hammer'' provision described below. In the interim, the

monitoring requirements in 40 CFR 70.6(a)(3) and 70.6(c) would apply.

Following publication of the notice of availability of example

protocol(s) for a process/pollutant combination, the time at which the

owner or operator would be required to submit a proposed enhanced

monitoring protocol would depend on the status of the title V operating

permit for the applicable facility. If the initial operating permit

application has not yet been filed for the facility, then the owner or

operator generally would be required to include a proposed protocol in

the initial application for an emissions unit subject to part 64 that

includes the relevant process/pollutant combination. In some

circumstances, notice that EPA's example protocols are available may be

published shortly before an affected source is obligated to submit its

permit application to the permitting authority. In such circumstances,

the source may submit its application as scheduled and then update the

application to include enhanced monitoring no later than 90 days after

publication of the notice of availability.

If the operating permit application is filed before EPA publishes

notice of availability of example protocol(s) for a process/pollutant

combination applicable to emissions units subject to part 64 at the

affected source, but the permitting authority has not yet published a

notice to request public comment on a draft permit, then the owner or

operator would be required to update the permit application within 90

days of publication of the example protocols(s) to address enhanced

monitoring for the emissions units covered by the example protocol(s).

If an application is filed and a draft permit is noticed for public

comment before EPA publishes a notice of availability of applicable

example protocols, then the owner or operator would not be required to

submit a proposed protocol until the earlier of: (1) the next

application for permit renewal; or (2) a reopening of the permit that

involves public notice and comment that is consistent with the type of

public notice and comment required by 40 CFR part 70 for approval of an

enhanced monitoring protocol.

The ``hammer'' provision would limit the duration of the phased-in

implementation process. Where enhanced monitoring is not required for

an affected emissions unit and applicable requirement under the

implementation schedule outlined above, the ``hammer'' provision would

mandate implementation of enhanced monitoring as of January 1, 2000.

There are three different scenarios in which the ``hammer'' provision

would apply. First, an enhanced monitoring protocol must be included

where applicable under part 64 in any title V permit issued after the

``hammer'' deadline, even if EPA has not issued guidance on a

particular process/pollutant combination. Second, an existing title V

permit that has not included an enhanced monitoring protocol required

under part 64 because EPA has not yet issued guidance for the

applicable process/pollutant combination would have to be reopened

expeditiously after the January 1, 2000 deadline to incorporate

enhanced monitoring. Finally, where an existing title V permit has not

included an enhanced monitoring protocol because EPA has issued

guidance only after the date of notice for public comment on the draft

permit, the permit would have to be reopened expeditiously after the

January 1, 2000 deadline assuming that the required enhanced monitoring

protocol had not been approved previously during a permit renewal or

reopening. The Agency requests comment on appropriate timeframes for

processing permit actions where the ``hammer'' provision requires an

expeditious reopening of an existing permit.

The Agency believes that including this type of ``hammer''

provision is essential to assure that the program is implemented in a

timely manner. This ``hammer'' provision would provide an incentive for

all parties to facilitate the development of example protocol guidance.

The Agency also believes that the experience gained over the next five

years and the publication of guidance for many types of process/

pollutant combinations will facilitate effective implementation for the

limited number of process/pollutant combinations for which the Agency

may not develop guidance before the January 1, 2000 deadline. The

Agency believes that guidance will be available for most affected

emissions units before the end of this time period. The Agency requests

comment on this ``hammer'' provision.

III. Consideration of Cost

Many industry representatives and some other groups commented that

the proposed rule would not allow adequate consideration of the costs

of various monitoring approaches in selecting enhanced monitoring for a

particular emissions unit. The Agency requests comment generally on how

the final rule should address the issue of considering cost in the

context of protocol selection and approval and specifically on whether

the final rule should be clarified to allow owners or operators to

select the least-cost monitoring protocol that can achieve the

requirements in the rule.

Some comments from industry representatives indicate that cost also

should be a consideration where the only monitoring approaches that can

meet the other part 64 criteria are not cost-effective for the

particular emissions unit. The EPA finds this an important issue and is

considering incorporating a more explicit role for the consideration of

cost in the selection and approval of enhanced monitoring. In the

notice of proposed rulemaking (NPRM), EPA discussed in numerous places

the importance of designing an enhanced monitoring program that would

both achieve cost-effective emissions reductions and also allow sources

to adopt monitoring methods that would satisfy the enhanced monitoring

standards in the most cost-effective manner. EPA thus sees the

consideration of costs in establishing enhanced monitoring as

consistent with the NPRM and the Clean Air Act. The Agency requests

specific comment as to whether and how the final rule should allow the

Agency to consider cost and effectiveness in developing guidance for

monitoring protocols.

The Agency also requests comment on whether the final rule should

allow, on a case-by-case basis and upon a demonstration by the owner or

operator that no monitoring approach that satisfies all of the part 64

criteria is cost-effective, the owner or operator to propose a cost-

effective monitoring approach that comes as close as possible to

achieving all the other part 64 criteria. The Agency also requests

specific comment as to what procedures and criteria should be used by

permitting authorities to evaluate such proposals by owners or

operators.

If EPA adopts this approach, EPA would define enhanced monitoring

as representing the monitoring for determining compliance, taking cost

and effectiveness into account. The basic purpose of Section 114(a)(3)

and associated sections of the Clean Air Act is to require all major

sources to conduct monitoring which will allow them to certify

continuous or intermittent compliance. However, nothing in Section

114(a)(3) dictates that all sources must certify to being in either

continuous compliance or else be considered in noncompliance; sources

may also certify to being in compliance as demonstrated on an

intermittent basis. For example, by virtue of consideration of cost (or

because the emissions unit is below the applicability threshold for

part 64) a source may not have monitoring data that is sufficient to

support a certification of continuous compliance but does provide the

basis for certification on an intermittent basis. EPA emphasizes that a

certification of intermittent compliance does not mean that a source

has operated in violation of applicable requirements. Rather, it merely

reflects the fact that under some enhanced monitoring protocols, a

source will only be able to gather enough data to certify compliance on

an intermittent basis. In order to ensure effective implementation of

enhanced monitoring and to minimize the burden on the operating permits

program, any approach related to protocol cost would, in EPA's view,

need to allow the permitting authority to make an expeditious

determination based on simple, direct criteria.

IV. Special Applicability for Nonattainment Areas and Incorporation of

Periodic Monitoring

Many industry representatives and several State and local agencies

commented that the proposed applicability of the rule covered too many

sources and emissions units, especially too many small emissions units.

Environmental groups commented that the proposed applicability was too

narrow and criticized any reduction in applicability. In response to

these comments, the Agency solicits comment on whether it would be

appropriate to have a second phase of applicability only for

nonattainment pollutants in nonattainment areas.

The Agency is considering applying part 64 primarily to emissions

units which emit, or have the potential to emit, a pollutant at or

above the applicable major source threshold, as defined under title V

of the Act. This approach would have the effect of significantly

reducing the number of sources and emissions units subject to part 64.

To address concerns that environmentally significant emissions units

would not be covered, the EPA is also considering the appropriateness

of a second phase of applicability, only for nonattainment pollutants

in nonattainment areas, in which all major sources which are major for

a nonattainment pollutant would be required to cover a prescribed

minimum percentage of their emissions units, perhaps with a de minimis

cutoff for very small units.

In such a second phase, part 64 could require each major source

which is located in a nonattainment area and major for a nonattainment

pollutant to conduct enhanced monitoring on at least 25% of its

emissions units that are subject to applicable requirements for the

nonattainment pollutant, except that it would not have to conduct

enhanced monitoring for that pollutant on any emissions unit which

emits, and has the potential to emit, less than 50% of the applicable

major source threshold. Emissions units would be selected for coverage

as part of the 25% requirement based on the potential to emit of the

units, with the largest selected first. Any emissions units already

required to conduct enhanced monitoring under the regular, first phase

of implementation would ``count'' toward the 25%.

The EPA believes that this second phase of applicability is

appropriate as a means of ensuring that emissions units that have the

potential to contribute significantly to nonattainment problems are

subject to enhanced monitoring while at the same time excluding the

smallest emissions units.

The EPA solicits comment on the appropriateness of requiring such a

second phase only in nonattainment areas (i.e., not in attainment

areas); the appropriate percentage threshold to use; whether and at

what level a de minimis level should be used to exclude small emissions

units; when and how such a second phase should be implemented in

connection with the title V permitting process; and on all other

aspects of such a second phase in nonattainment areas. After reviewing

any comments received, EPA may proceed to finally promulgate a second

phase without further opportunity to comment.

The EPA realizes that the applicability approach described above

may still leave some major sources with no emissions units subject to

enhanced monitoring requirements in part 64. To satisfy the statutory

obligation that all major stationary sources conduct enhanced

monitoring, the preamble to the proposed rule stated EPA's intent to

rely on periodic monitoring under 40 CFR part 70 as sufficiently

enhanced for small units under the size threshold proposed by EPA. The

Agency also requested comment on the possibility of relying upon a de

minimis exemption theory as allowed under Alabama Power v. Costle, 636

F.2d 323 (D.C. Cir. 1979).

Accordingly, EPA solicits comment on the appropriateness of relying

in part on periodic monitoring under 40 CFR part 70 to satisfy the

Agency's obligation to require enhanced monitoring for all major

sources.

The Agency also solicits comment on whether to codify this link

between enhanced and periodic monitoring by specifically including the

rule language from 40 CFR 70.6(a)(3)(i) into a separate subpart of part

64. A separate subpart of part 64 could provide that at a major source,

for all emissions units and applicable requirements that do not meet

the applicability thresholds for the enhanced monitoring requirements

discussed in the proposed rule and in this notice, the source must

conduct monitoring, to the extent necessary to comply with 40 CFR

70.6(a)(3)(i) and 70.6(c)(1) and (5), that is periodic monitoring

sufficient to yield reliable data from the relevant time period that

are representative of the source's compliance with the permit. Such

monitoring requirements would be required to assure use of terms, test

methods, units, averaging periods, and other statistical conventions

consistent with the applicable requirement.

Such a codification of existing part 70 language into part 64 would

not be intended to alter, or add to, the existing part 70 monitoring

requirements. Rather, this codification would merely make clear that

EPA considers existing periodic monitoring requirements as partial

fulfillment of its obligation to require enhanced monitoring for all

major sources.

Finally, in a separate section above, the Agency discusses the

potential role of cost in selecting enhanced monitoring. In this

context, EPA may also consider periodic monitoring approaches under

certain circumstances as one of the ways of achieving more cost-

effective monitoring approaches.

Dated: December 20, 1994.

Carol M. Browner,

Administrator, U.S. Environmental Protection Agency.

[FR Doc. 94-31742 Filed 12-27-94; 8:45 am]

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