June 21, 2004

The Honorable Michael O. Leavitt

Administrator

U.S. Environmental Protection Agency

Ariel Rios Building -- 1101 A

1200 Pennsylvania Avenue N.W.

Washington, DC 20460

**Re: Petition for Reconsideration: Iron and Steel Foundry MACT
Standards**

Dear Administrator Leavitt:

National Emission Standards for Hazardous Air Pollutants ("HAPs") for
Iron and Steel Foundries ("Foundry MACT") were published in the Federal
Register on April 22, 2004. *See* 69 Fed. Reg. 21906. Extensive comments
on the proposed rule (*see* 67 Fed. Reg. 78273, December 23, 2002) were
filed by American Foundry Society ("AFS")[^1] and many of its members.
These comments addressed numerous facets of the proposed rule and in
some cases asked for revisions or clarifications to the regulatory
language. Several of these issues were also raised in subsequent
communications with United States Environmental Protection Agency ("EPA"
or "Agency") staff. However, in the preamble, background documents, and
the rule itself, EPA has failed to respond to these concerns, make the
necessary clarifications or corrections, or provide the rationale for
its actions or inaction.

For these reasons, and as explained in more detail below, we believe the
final rule is flawed. Therefore, on behalf of AFS, we hereby petition
EPA for reconsideration of the rule in accordance with section
307(d)(7)(B) of the Clean Air Act. In some cases, we believe technical
amendments to the rule or implementation guidance may suffice. In other
cases, amended regulatory language is needed. Based upon conversations
we have had with Agency representatives and its contractors, many of
these changes appear to be non-controversial, and we have grouped these
together along with our suggestions for addressing our concerns. In
those cases where proposal of a modified rule is necessary, EPA can, as
it has in other cases, simultaneously issue a direct final rule along
with a proposed rule that would be superceded by the direct final rule
if no adverse comments are received.

In light of the compliance timetable faced by facilities that are
subject to the Foundry MACT -- including a deadline of April 22, 2005,
to comply with specified work practice standards and April 23, 2007, to
meet applicable emissions standards -- it is important that the Agency
act with expediency in responding to this petition. In recognition of
the need for a timely decision, representatives of AFS stand ready to
meet with EPA staff to discuss these issues and answer questions or
provide clarification at your staff's convenience.

The comments below make the following requests:

-   Establish a separate subcategory and associated emission limits for
    cupolas with scrubbers.

-   Reconsider the scope of the work practice standard and re-propose
    work practices associated with mercury in automotive scrap.

-   Establish a separate category or subcategory of sources under the
    Foundry MACT for steel foundries with separate requirements, if
    justified, specific to the subcategory.

-   Reconsider the MACT floor for scrap preheaters and exclude scrap
    dryers from any scrap preheating requirements.

-   Revise the basis for the total metal HAPs alternative to be
    consistent with data and test methods used as a basis to develop the
    rule.

-   Issue implementation guidance or amend the rule to provide clarity
    and to avoid misinterpretation for numerous provisions of the rule.

I.  **SUBCATEGORIZATION OF CUPOLAS WITH SCRUBBERS**

The final Foundry MACT rule establishes a particulate matter ("PM")
emission limit for cupola furnaces that is based solely on the
utilization of fabric filter control systems, or baghouses. As noted in
AFS's comments on the proposed rule, the foundry industry has many
cupolas that are equipped with wet scrubbers that operate very
efficiently but are not capable of meeting the emission limits
characteristics of baghouses. AFS estimates that the capital investments
to replace these scrubbers with baghouses would amount to almost \$400
million and annualized costs would amount to about \$45 million. Yet
according to EPA estimates, the replacements would achieve additional
HAP reductions of only 64 tons per year.[^2] Therefore, the incremental
HAP removal costs of replacing scrubbers with baghouses corresponds to
approximately \$700,000 per ton of HAPs removed, which is excessive by
any reasonable standard.

The Agency has authority under § 112(d)(1) of the Clean Air Act to
"distinguish among classes, types, and sizes of sources within a
category or subcategory." AFS believes it is incumbent upon the Agency,
in light of the relatively small additional HAPs reductions, as well as
the economic burden on the foundry industry, to reconsider the
baghouse-based emission limit and establish an emission limit for that
"class" or "type" of cupolas equipped with wet scrubbers. In addition,
EPA should reconsider the form of the emission standard and explore
alternative emission limitations (*e.g.*, quantity of HAP emissions per
ton of iron production) to determine if the corresponding MACT floor
applicable to such an alternative would provide a more cost-effective
standard. In performing such an analysis, the Agency should evaluate the
adverse air quality effects of replacing scrubbers in view of their
inherent ability to remove criteria pollutants such as sulfur dioxide
and nitrogen oxides, as well as their potential for greater control of
certain HAPs due to lower gas stream discharge temperatures.

II. **WORK PRACTICE STANDARDS (SCRAP MANAGEMENT)**

The final rule establishes both numerical emission limits and work
practice standards. Both are intended to regulate HAP emissions from
sources of PM, which serves as a surrogate for metal HAPs, and volatile
organic HAPs ("VOHAPs"), which serves as a surrogate for organic HAPs.

In the case of work practices, the rule gives foundry operators two
options to comply with the work practice standards. One is to operate
according to a written certification that foundry scrap purchases
exclude certain materials (post-consumer automotive body scrap and
engine blocks, oil filters, oily turnings, lead components, mercury
switches, plastics or organic liquids). The second option is to operate
according to an EPA-approved written plan for selecting and inspecting
scrap to minimize, to the extent practicable, amounts of organics and
HAP metals in charge materials (used oil filters, plastic parts, organic
liquids, free liquids, automotive mercury switches, and accessible
automotive lead components). The scope of this work practice standard in
the final rule significantly exceeds the scope of the management plan in
the proposal, which would have required only a plan "to minimize, to the
extent practicable, the amount of organics and HAP metals in the charge
materials used by the casting department." The proposed rule identified
only free liquids, grease, oils, painted parts, plastic parts (potential
sources of VOHAPs) and lead components (potential sources of metal HAPs)
as materials of concern.

The specified work practices are intended to eliminate or reduce
precursors for VOHAPs or metal HAPs, in particular, lead and mercury.
Section 112(d)(2) of the Clean Air Act gives EPA authority to utilize
multiple means or a combination of means to achieve necessary HAP
emission reductions. However, paragraph (D) of that section requires
that any promulgated work practice standards must comport with § 112(h),
and § 112(h)(1) states "if it is not feasible ... to prescribe or
enforce an emission standard ... the Administrator may, [in lieu
thereof]{.underline}, promulgate a ... work practice, or operational
standard ..." (Emphasis added.) Section 112(h)(4) goes on to state:
"Numerical Standard Required. -- Any standard promulgated under
paragraph (1) shall be promulgated in terms of an emission standard
whenever it is feasible to promulgate and enforce a standard in such
terms." Because EPA has promulgated emission standards for VOHAPs and
metal HAPs for these sources, and has raised no issue regarding
feasibility or enforcement of those emission standards, the imposition
of an additional work practice standard "in lieu thereof" an emission
limit is unlawful.

The background information document for the promulgated standards[^3]
("Final Rule BID") asserts that particulate control devices for melting
furnaces are ineffective for mercury control and that reduction of
mercury in scrap provides for more direct reduction of mercury
emissions, but the Agency provides no substantive technical support for
this statement. Even if that claim has validity, however, it is no cause
for expanding scrap certification or scrap management plans beyond
efforts to minimize mercury. With respect to lead, the Final Rule BID
cites data from two cupola systems that show "excellent control of lead
emissions" and merely speculates about possible reduced lead removal
efficiency in other situations. Hence, any work practice standard
applicable to lead is redundant with the PM or metal HAPs emission
standards. With respect to precursors for VOHAPs (*e.g.*, plastics,
oils), the Final Rule BID provides no justification at all for a
duplicative, redundant work practice standard.

Moreover, because of the introduction of language pertaining to mercury,
the work practice provisions in the final rule are significantly
different than those in the proposed rule. AFS has been denied an
effective opportunity to comment on the expensive work practice standard
for the purpose of demonstrating, for example, infeasibility, market
disruption and other concerns.

In addition, EPA acknowledges in the Final Rule BID that the
mercury-in-scrap requirement is a beyond-the-MACT-floor alternative, in
which case the Agency is obliged to assess the cost-effectiveness of the
alternative. While a meager attempt is made to assign cost to the
alternative, the cost estimates (\$3.6 million per year for the entire
industry) are plainly inadequate and understated. For example, the costs
do not appear to include the significant foundry operator cost burden of
inspecting 10 percent of all scrap shipments, as promulgated in the
final rule. Furthermore, while we firmly believe the responsibility for
removing mercury switches rests with the auto dismantlers and scrap
suppliers, it is not evident in the Final Rule BID that the costs for
these activities are addressed.

For these reasons, EPA must reconsider the work practice standard *in
toto* and in particular must re-propose and justify any work practices
related to controlling mercury in scrap and its implications for foundry
operators.

III. **STEEL FOUNDRY SUBCATEGORIZATION**

When EPA first listed source categories as candidates for considering
regulation under section 112 of the Clean Air Act, iron foundries and
steel foundries were listed as separate source categories. Separation of
ferrous foundries into these two groups was and is appropriate because
of significant differences in the raw materials, processes, operations,
control technologies, and types and quantities of HAP emissions that are
characteristic of the two industry classifications. During the Foundry
MACT rulemaking process, iron and steel foundries were combined into a
single source category, ostensibly for no other reason than
administrative and regulatory convenience and efficiency, and that
action has led to the imposition of regulatory requirements for steel
foundries that are not justified by the magnitude of HAP risks posed by
steel foundries. Early discussions with the Agency during the
development of the rule suggested an understanding of the need for
separate categorization of steel foundries, but the rule was proposed
without consideration of the distinct differences from iron foundries.

In the background information document ("BID") produced to respond to
comments on the proposed rule, EPA acknowledges its original intent to
develop separate standards for iron and steel foundries but justifies
its decision for setting a common standard by asserting there are
process similarities and that some foundries produce both iron and steel
castings. *Ibid*. However, neither of these arguments effectively
responds to industry comments or provides justification for the sweeping
application of iron foundry standards to steel foundries.

While there are some similarities in processes, there are far more
differences. Following is a summary of factors to substantiate this
conclusion.

-   Steel foundries produce different products and serve different
    markets than iron foundries. The technical requirements of these
    products dictate different processes that have different emissions
    and controls.

-   Steel foundries employ either electric induction or electric arc
    furnaces to melt steel scrap to produce molten metal to make
    castings. Although iron foundries also use electric furnaces, they
    more typically use cupolas to melt scrap. The emission
    characteristics and air pollution control systems on electric
    furnaces used in steel foundries are much different than those of an
    iron foundry cupola.

-   Most steel foundries also have lower production capacities than iron
    foundries. In fact, the largest iron foundry has a capacity greater
    than the entire output of the steel foundry industry. Most steel
    foundries do not qualify as major sources or have achieved synthetic
    minor status and would not be subject to the MACT rule as a
    stand-alone facility. However, because some steel foundries are
    located at larger production facilities where other HAP sources may
    make the larger facility a major source, the steel foundry
    operations at those facilities would be subject to Foundry MACT
    requirements, absent an exclusion, even if minor of their own
    accord.

-   Steel foundries also use significantly different molding methods,
    binder formulations, and pouring methods as compared to iron casting
    operations. Steel foundries using green sand molding do not use sea
    coal, which has been identified as the largest source of HAPs in
    casting. Steel foundries also use different chemical binders for
    core making and no-bake molds because of different requirements for
    set times. Pouring practices also vary significantly.

These fundamental differences in processes result in significant
differences in types and amounts of HAP emissions and require separate
calculation of MACT floors and emission limits. EPA has failed
adequately to explain its decision not to regulate steel foundries as a
separate subcategory.

With respect to production of both iron and steel castings at the same
facilities, because iron castings require lower temperatures, a few
steel foundries do produce iron castings as well, but the practice is
relatively rare. In those cases, iron foundry MACT standards would apply
to iron casting operations, but that is no justification for applying
the iron foundry requirements to all steel casting operations. Just as
it would be inappropriate to apply Integrated Iron and Steel
Manufacturing MACT standards to facilities that also have electric arc
furnace steelmaking capability, it is also improper to apply standards
developed for iron foundries to steel foundries.

Finally, EPA notes in the BID that because at least one steel foundry
facility has a permit-based potential to emit greater than 25 tons/year
of HAPs, the Agency is "obligated to develop MACT standards for steel
foundries." Section 2.1 of BID. However, the BID also notes that some
steel foundries with the estimated potential to emit more than 25
tons/year of HAPs have opted to accept limits through a federally
enforceable State operating permit to reduce their potential to emit to
less than major source threshold limits. The Agency thus acknowledges
that facilities with potential to emit more than 25 tons/year of HAPs
can obtain synthetic minor status and be excluded from MACT
applicability. Accordingly, EPA should not use a single example of a
facility that has not yet sought that status as justification for
establishing MACT limits for an entire industry, especially since those
emission limits are based primarily upon data from iron foundry
processes.

Based upon these factors, AFS requests that EPA reconsider the
applicability of the Foundry MACT standard to steel foundries. At the
very least, the Agency should consider steel foundries as a separate
subcategory and develop and re-propose requirements suited to that
subcategory. The creation of a separate steel foundry subcategory is an
essential step to allow for consideration of a risk-based delisting that
we believe is appropriate for steel foundries.

IV. **SCRAP PREHEATER REQUIREMENTS**

**A. MACT for Scrap Preheaters**

For scrap preheaters, EPA has promulgated alternative standards intended
to limit VOHAP emissions. The alternatives include a work practice
standard requiring use of certified scrap, a work practice standard
requiring use of direct flame-fired scrap preheating, or a 20 parts per
million by volume ("ppmv") VOHAP emission limitation. In promulgating
these options, EPA responded in part to comments raised by AFS and
others on the proposed rule but still has failed to justify these limits
as a MACT floor. AFS believes that proper assessment of the database
leads to the conclusion that the MACT floor for scrap preheating is no
control for VOHAPs and requests EPA's reconsideration of the scrap
preheater standard.

The Foundry MACT rule initially proposed by EPA established a VOHAP
emission limit of 20 ppmv from scrap preheaters. EPA concluded "... we
cannot use scrap preheater emissions data to directly calculate an
emissions limit for organic HAP from scrap preheaters." 67 Fed. Reg.
78288. However, based on EPA's analysis concluding that afterburners
were installed on a sufficient number of facilities to qualify the
technology as MACT, and EPA's mere assumption that scrap preheater
afterburners perform in a manner similar to thermal incinerators in
other applications, the Agency proposed the 20 ppmv VOHAP emission
limit.

Based upon comments submitted by AFS and others disputing the MACT floor
analysis and taking exception to the scrap preheater limits, EPA agreed
there were not sufficient preheater afterburner installations to qualify
the technology as MACT. Instead, EPA elected to establish work practice
standards requiring the use of direct flame contact preheaters, which is
the technology utilized by the majority of scrap preheaters, or
afterburners, or the use of certified scrap. However, the final standard
retains the 20 ppmv VOHAP emission limit for preheaters equipped with
afterburners or indirect flame-fired preheaters.

In promulgating the final rule, EPA still has not provided any emissions
data to justify setting a VOHAP standard for scrap preheaters. Although
direct flame contact units are the dominant type of scrap preheater in
use, there are no data to characterize VOHAP emissions from that
technology. Moreover, no additional data have been developed or
presented to show that other preheaters using afterburners or indirect
heating methods are capable of achieving a 20 ppmv VOHAP standard. For
these reasons, EPA's MACT floor analysis is still flawed, and EPA must
reconsider the scrap preheater work practice and VOHAP standards and
conclude that MACT is no control for scrap preheaters.

B.  **Distinction Between Scrap Preheaters and Scrap Dryers**

If a scrap preheating emission standard or alternative work practice
standard is retained after reconsideration, AFS believes it is important
to draw a distinction between scrap drying and scrap preheating. Section
63.7765 of the rule defines a scrap preheater as follows:

> Scrap preheater means a vessel or other piece of equipment in which
> metal scrap that is to be used as melting furnace feed is heated to a
> temperature high enough to eliminate moisture *and other volatile
> impurities or tramp materials* by direct flame heating or similar
> means of heating. \[Emphasis added.\]

As implied by this definition, the primary purpose of a scrap preheater
is to add sufficient heat to the charge materials to shorten the furnace
melting cycle, and sufficient energy is typically added to elevate the
temperature of the charge materials to temperatures of 900^o^F to
1200^o^F. A scrap dryer, on the other hand, is a vessel in which charge
materials are heated to a temperature just sufficient to remove water or
moisture, typically 400^o^F to 600^o^F. Dried scrap is not necessarily
charged to the furnace immediately after processing as is the case of
scrap preheating. Scrap drying is undertaken as a safety measure to
remove water that can be a potential explosion hazard if it comes into
contact with molten metal, and has far less potential for driving off
volatile materials that might contribute to VOHAPs than do scrap
preheaters operating at much higher temperatures.

EPA's BID for the proposed rule identified 177 scrap preheaters in the
U.S. This number (later corrected to 169 based on AFS comments) does not
include scrap dryers. For this reason, scrap dryers were not included in
the database for assessing the scrap preheater MACT floor and therefore
should not be regulated in the same manner as scrap preheaters.

AFS therefore recommends removing the term "moisture and other" from the
definition of scrap preheater in § 63.7765 to make clear that practices
designed for scrap drying only are not covered by this rule.

C.  **Performance Testing of Scrap Preheaters**

If an emission limit for scrap preheaters is retained after
reconsideration, AFS has concerns with requirements for performance
testing of scrap preheaters. Sections 63.7732(b)(5) and (c)(5) specify
that testing of scrap preheaters is to be performed "only when scrap is
being preheated." Scrap preheaters operate on a batch basis and do not
heat scrap for extended periods of time. Typically, individual charges
are heated for several minutes, and gaps of non-heating time between
charges are part of normal operating procedure. It is not practical to
start and stop emission tests every few minutes over the course of time
required to preheat numerous charges in order to sample the minimum
one-hour testing period to constitute an acceptable performance test.
Such intermittent testing increases the potential for errors and flawed
stack tests.

AFS believes that proper testing of scrap preheaters should be
continuous over the period of one hour. We believe this is consistent
with § 63.6(f)(2(iii)(A) of the NESHAP General Provisions, which states
that a performance test must be "conducted under representative
operating conditions of the source." We believe that periods of
preheating and gaps between preheating cycles are "representative
operating conditions" for scrap preheaters. Accordingly, AFS requests
that EPA revise the rule to specify that procedure for scrap preheater
performance testing.

D.  **Installation of Scrap Preheaters**

Language in the final rule's preamble (69 Fed. Reg. 21908) and in
§ 63.7700(e)(1) may be interpreted to require foundries to "install"
gas-fired preheaters, even when not necessary for foundry operations. We
believe it is obvious that it is not the intent of the regulation to
mandate installation of preheaters, but rather to establish requirements
for those existing facilities that utilize scrap preheaters.
Accordingly, we request that language in paragraph (e)(1) be amended to
read as follows:

> \(1\) Foundries that utilize scrap preheaters must operate and
> maintain a gas-fired preheater where the flame directly contacts....

V.  **SCOPE OF HAP METALS REGULATION**

For foundry processes subject to a PM emission standard, the rule
establishes an alternative emission limitation for "total metal HAPs."
Companies seeking to utilize this alternative are required to
demonstrate compliance by using Method 29. While AFS supports the
inclusion of the total metal HAPs alternative in the rule, we have
concerns reconciling the basis for those total metal HAP standards and
implementation of this aspect of the rule. In establishing the
alternative, EPA relied primarily on lead and manganese emissions data.
In addition, limited data for cadmium, chromium, nickel, and mercury
were used to estimate other HAP metals emissions and compute the total
metal HAP emission limit. Because data used in developing the
alternative metal HAPs standards were collected using only a subset or
modified version of Method 29, it is inconsistent and inappropriate to
use Method 29 as a basis for assessing compliance.

Method 29 includes three HAP metals (antimony, beryllium, and cobalt),
which were not identified with foundry processes. In addition, Method 29
includes several analytes that are not even metals (arsenic,
phosphorous, and selenium). It is not clear from background documents or
the preambles to the proposed or final rule whether Method 29 or some
subset of Method 29 results was used to derive the alternative numerical
metal HAPs limits. Because data used to develop the total metal HAPs
limits were not consistent with Method 29, there is no basis for
including all Method 29 metal analytes when demonstrating compliance
with the total metal HAPs limits.

AFS believes EPA cannot establish a limit for total metal HAPs, for
which compliance is determined by a specific test methodology, if that
method was not used as a basis for developing data to support the
alternative total metal HAPs limitations. Accordingly, we request
reconsideration of this aspect of the rule to conform the compliance
test methodology to those performance data used to establish the
standard.

VI. **OTHER ISSUES REQUIRING IMPLEMENTATION GUIDANCE OR MINOR CHANGES IN
    REGULATORY LANGUAGE**

The issues discussed in this section represent those matters that have
been discussed with the Agency and where there is general agreement that
implementation guidance or minor, non-controversial rule changes are in
order. Nevertheless, we are including them in our petition for
reconsideration, along with recommendations and suggestions for
remedies, to assure the concerns are adequately described and addressed.

A.  **Clarifying Changes If Work Practice Standards Are Retained**

Apart from our request for reconsideration of the entire scrap
management work practice standard (*see* Section II of this petition),
there are several aspects of the work practice standard as promulgated
that require clarification if the standard is retained. These issues are
discussed below.

1.  **Multiple Scrap Acquisition Plans Should Be Permitted**

Section 63.7700 requires foundry operators to manage scrap inputs to the
melting process in one of two ways. The facility must either certify
that the purchase and use of scrap materials is free of certain types of
materials, specified in § 63.7700(b), or prepare and operate in
accordance with a selection and inspection plan to minimize organics and
HAP metals in charge materials, specified in § 63.7700(c). In both
cases, the regulation requires facilities to "operate at all times
according to" the selected option. These requirements may be interpreted
to mean that a facility must choose only one of the two options and fail
to recognize that foundry operators may utilize both methods depending
upon products, processes, or availability of melt materials. For
example, a foundry may have both an electric furnace and a cupola at the
same site and may utilize "certified" materials in the electric furnace
operation but utilize non-certified materials subject to a selection and
inspection plan in the cupola. Similarly, some castings may warrant
production using "certified" raw materials while other castings may not.
For these reasons, as well as varying market conditions and
corresponding availability of scrap types, companies need to have the
flexibility to operate under either or both scrap acquisition options.

AFS requests revisions or clarifications to the regulatory language or
implementation guidance to make clear that foundry operators may utilize
either or both scrap acquisition options provided the materials
qualifying under each option are appropriately designated and remain
segregated.

2.  **Scrap Certification Responsibility Should Be Identified**

Section 63.7700(b) offers the option of preparing and operating
according to a "written certification" that the foundry purchases and
uses scrap free of certain types of materials, presumptively those that
are potential sources of HAPs. It is not clear in the rule who must
certify these materials -- the supplier or the foundry operator -- or
what form the certification should take. However, Agency representatives
have indicated in discussions on the meaning of the rule that it was
EPA's intention to place this responsibility with the foundry operator.

AFS has concern with the absolute nature of the certification option
described in § 63.7700(b) as compared to the alternative scrap selection
and inspection plan described in § 63.7700(c). Paragraph (b) requires
certification that "the foundry [purchases and uses only]{.underline}
... materials that [do not include]{.underline} \[certain materials\]."
(Emphasis added.) Paragraph (c), on the other hand, requires operating
according to a plan "to [minimize]{.underline}, [to the extent
practicable]{.underline}, the amount of organics and HAP metals in the
charge materials ...." (Emphasis added.) Foundry operators can issue
specifications and make other efforts to do their best to exclude
problematic materials listed in paragraph (b), but they have no absolute
control over sources of scrap materials and should not be held
accountable for non-compliance with an absolute certification
requirement. Otherwise, the foundry operator is exposed to an
unreasonable standard of certainty that presents little room for
enforcement discretion.

Accordingly, AFS recommends inserting the phrase "to the extent
practicable" after the word "uses" in § 63.7700(b). This addition places
the certification option on an equal footing with the requirements of
the scrap selection and inspection plan articulated in paragraph (c).

**3. Classification of "Cleaned" Scrap Materials**

The scrap certification option described in § 63.7700(b) identifies
specific scrap materials that are prohibited, including "...
post-consumer engine blocks, oil filters, \[and\] oily turnings ..."
This outright prohibition does not allow for the recycling and use of
these materials if they have been processed to remove contaminants of
concern. For example, some suppliers dismantle or crush, and then wash,
post-consumer engine blocks prior to shipment as scrap material.
Likewise, some scrap suppliers process oily turnings or used oil filters
in a manner that makes them suitable and environmentally acceptable for
introduction into the melting process.

AFS believes that provisions should be included in the rule to allow for
the use of materials that have undergone a cleaning process prior to
melting. We request a modification to the rule to allow for the use of
scrap materials under § 63.7700(b) if they have been processed to remove
contaminants of concern, consistent with the intent of the certification
option. In the alternative, § 63.7700(b) should provide for a procedure
to allow foundry operators to seek approval for a site-specific
modification to the list of certified materials to include cleaned
materials.

> **4. Unused Oil Filters Should Not Be Excluded from Certified
> Materials**

The list of materials prohibited from certified scrap in § 63.7700(b)
includes "oil filters" without regard to whether the filters have been
used. Unused oil filters pose no risk of organic HAP emissions.

AFS requests a minor modification to the regulatory language to clarify
that prohibited materials include only "used" oil filters. We believe
this was the intent of the rule, as evidenced by the use of the term
"used oil filters" in § 63.7700(c)(1)(i), and the requested change would
be consistent with that language.

A.  **Applicability of Alternate Emission Limitations**

For a number of foundry processes, the rule establishes a PM emission
standard but provides for an alternate emission standard for total metal
HAPs. AFS requests that the Agency clarify in implementation guidance
that: (1) a demonstration to show compliance with either emission limit,
but not both, is acceptable at any time; (2) permit provisions can
provide for either method of demonstrating compliance; and (3)
demonstrating compliance by one method does not preclude a demonstration
of the alternate method at a later date.

B.  **Opacity-Related Issues**

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1.  **Fugitive Emissions Opacity**

Section 63.7690(a)(7) establishes opacity limits for fugitive emissions
from "each building or structure housing any emission source at the iron
and steel foundry." This provision could be interpreted to apply to
fugitive emissions that are unrelated to regulated sources under the
Foundry MACT rule, which may be foundry-related sources for which no
requirements exist or operations in other source categories that may be
co-located in foundries.

A related concern is the potential applicability of operation and
maintenance ("O&M") plans to unregulated operations. Section 63.7710(b)
requires a written O&M plan for each capture and collection system and
control device for each emission "source" subject to an emission limit
in § 63.7690(a). Because the term "source" could be misconstrued to mean
the entire foundry building, and since § 63.7790(a)(7) establishes an
emission limit (opacity) for structures that may house both regulated
and non-regulated operations, the O&M requirement could be
misinterpreted to apply to non-regulated sources within the building,
including all ventilation (*i.e.*, capture and collection) equipment.

AFS requests modification of language in § 63.7690(a)(7) and
§ 63.7710(b) to make clear that the fugitive emission opacity
requirement and corresponding O&M plans apply only to those emission
units and operations to which the Foundry MACT regulation applies. To
make these requirements clear, we suggest adding the phrase "from those
units subject to this NESHAP" between the words "discharge" and "any" in
§ 63.7690(a)(7). In addition, AFS requests modification of language in
§ 63.7710(b) to replace the term "source" with "unit."

2.  **Overlapping Opacity Observations with Emission Testing**

Section 63.7732(d)(2) requires that opacity observations to demonstrate
compliance with the fugitive emission opacity standard in
§ 63.7690(a)(7) "overlap with the PM performance tests." AFS understands
the objective of this provision to be an assurance that during testing
of operations to demonstrate compliance with PM emission limits,
emissions are not escaping from those operations to such a degree that
building opacity limits are exceeded. However, because opacity
demonstrations are to be conducted at six-month intervals while PM
performance tests are required only once every five years, it is not
feasible for opacity observations to "overlap" with PM performance tests
in all cases.

Accordingly, we believe the language of § 63.7732(d)(2) needs to be
revised to reflect the intended obligation to conduct concurrent
observations of building opacity for emissions related to those
operations for which PM performance tests are being conducted. We
suggest that paragraph (d)(2) be revised as follows:

> During PM performance tests of emission sources subject to this rule,
> conduct each test such that the opacity observations are concurrent
> with and associated with emission sources for which the PM performance
> tests are being conducted.

3.  **Notifications for Periodic Opacity Performance Testing and
    Submittal of Results**

Section 63.7731(b) requires performance tests every six months to
demonstrate compliance with building opacity limits, and § 63.7750(d)
requires notifications of intent to conduct performance tests to be
submitted at least 60 days prior to conducting the test. In light of the
frequency of necessary opacity performance testing and the relative ease
of performing opacity observations, AFS believes the 60-day notification
for opacity performance demonstrations is unnecessary and burdensome and
should be deleted.

In addition, § 63.7750(e)(2) specifies that results of performance tests
must be submitted within 60 days following the completion of the
performance test. This is consistent with NESHAP General Provisions
§ 63.10(d)(2), which requires the 60-day submittal of test results
unless otherwise specified in the rule. In light of the semi-annual
building opacity testing requirement, AFS requests a rule change that
allows results of the semi-annual opacity testing to be reported as part
of the semi-annual compliance report required under § 63.7751. This will
reduce the need for a separately submitted report that would otherwise
add an unnecessary administrative burden.

D.  **Bag Leak Detection Issues**

    1.  **Requirements for Use of Bag Leak Detection Systems**

Section 63.7741(b) of the rule requires the installation, operation, and
maintenance of bag leak detection systems. While it may be intuitively
obvious that bag leak detection systems are required only for baghouses
employed to meet PM emission requirements of the rule, this is not clear
by the language of the rule and could be misconstrued to apply more
broadly. Accordingly, paragraph (b) should be amended to begin with the
phrase, "For each baghouse subject to operating limits in § 63.7690(a)
\..."

In addition, the rule fails to provide for legitimate exceptions to the
requirements for bag leak detection systems. EPA's guidance document
pertaining to bag leak detection states that "... only fabric filters
... with exhaust stacks are covered by this guidance." [^4] Some foundry
baghouses are positive pressure baghouses, which typically do not
utilize exhaust stacks. This type of baghouse typically has compartments
discharging to a common plenum that discharges to the atmosphere through
louvered openings in the plenum, making the use of bag leak detectors
impractical. EPA has recognized this problem in promulgating other MACT
standards (*e.g.*, *see* Ferroalloys Production MACT -- 40 CFR 63
Subpart XXX) by exempting the use of bag leak detection systems for
positive pressure baghouses without stacks, consistent with the EPA
guidance document. In addition, in the description of baghouse leak
detection monitoring requirements in § 63.7740, paragraph (b) qualifies
the application of bag leak detection requirements. Therefore, AFS
requests that § 63.7741(b) be amended to begin with the phrase "For each
negative pressure baghouse or positive pressure baghouse equipped with a
stack, you must install \..."

Section 63.7741(b)(3) also specifies that bag leak detection systems be
equipped with audible alarms. Based on AFS member experience, visual
alarms can, in some cases, be more effective and should not be excluded
as an independent notification method. We therefore suggest rewording
§ 63.7741(b)(3) as follows:

> The system must be equipped with an alarm that will sound or signal
> ... and ... must be located such that it can be heard or seen by the
> appropriate plant personnel.

2.  **Bag Leak Detector O&M Plans**

Section 63.7736(c)(1) states that a bag leak detection system monitoring
plan must be "submitted ... for approval" to the Administrator in
accordance with requirements of § 63.7710(b). However, § 63.7710(b)
states that O&M plans are "subject to approval" by the Administrator.
AFS believes the bag leak detection O&M plan can be incorporated into
the overall O&M plan for the regulated operations in the foundry and
does not need a separate plan or required approval. Therefore, we
request the language in § 63.7736(c)(1) be amended to read as follows:

> You have prepared a bag leak detection system monitoring plan subject
> to approval by the Administrator according to requirements in
> § 63.7710(b);

E.  **Performance Testing Issues**

> **1. Single Performance Tests for Control Devices Serving Multiple
> Units**

Section 63.7734(a)(1) through (6) states that compliance with PM
emission limits is demonstrated when determined by performance testing
for "each" process unit. In some cases, a common emission control system
may serve two similar or identical cupolas, but only one cupola is
operated at a given time. A performance test of the control device while
serving one cupola provides evidence of the control system's performance
capability. Similarly, in other cases, a common control device may serve
multiple furnaces or process units. In these cases, requirements for
separate tests of the control device while each of the melting furnaces
or process units is operating are redundant and impose unnecessary
costs.

AFS requests the addition of regulatory language, perhaps as a separate
paragraph in § 63.7734, to make clear that a single PM performance test
of a control device serving multiple furnaces or process units is
sufficient to demonstrate compliance, provided the test is conducted
during operation of the process unit or units corresponding to the
maximum operating condition of the control system.

**2. Performance Testing Procedures for Electric Furnaces**

Sections 63.7732(b)(4) and (c)(4) specify that testing of electric arc
and electric induction furnaces is to be performed "when scrap is being
melted." This is an unnecessary and inappropriate restriction on
performance testing of electric melting furnaces. Typically, electric
furnaces are charged with scrap metal and an electric current is
imparted directly or indirectly to the scrap to begin the melting
process. However, during the heat, the "melting" process may be
temporarily suspended to allow for the addition of additional scrap
charges or alloying agents, to take samples or temperatures, or perform
other required operations, before the furnace heat is tapped. All of
these phases occurring during the course of a heat are considered part
of typical operation. As we have noted above in our discussion of
performance testing of scrap preheaters, it is not practical to start
and stop emission tests over the course an electric furnace heat until
the requisite sampling time is accumulated because such intermittent
testing increases the potential for errors and flawed stack tests.
Moreover, as also noted above, we believe that testing during all phases
of operation is consistent with § 63.6(f)(2(iii)(A) of the NESHAP
General Provisions, which states that a performance test must be
"conducted under representative operating conditions of the source." We
believe that all activities occurring during the course of an electric
furnace heat, whether "melting" is occurring or not, constitutes
"representative operating conditions" for electric furnaces.

It is instructive to refer to the New Source Performance Standards for
Electric Arc Furnaces[^5] ("EAF NSPS") for considering the application
of emission limits and performance testing of electric melting furnaces
because operations of electric arc furnaces and electric induction
furnaces in iron and steel foundries are similar to operation of
electric arc furnaces in steelmaking plants, The EAF NSPS requires
performance testing over an integral number of heats to obtain the
requisite sample and defines a heat as "... the period beginning when
the scrap is charged to an empty \[electric arc furnace\] and ending
when the \[furnace\] tap is completed." AFS requests that EPA reconsider
the basis for performance testing of electric arc and induction furnaces
and revise the rule to adopt performance testing requirements
conceptually consistent with the EAF NSPS.

3.  **Compliance Demonstrations Using Method 29 Metal HAPs**

Section 63.7732(c) specifies the use of Method 29 when exercising the
option of demonstrating compliance with a "total metal HAP" limitations
specified in § 63.7690(a)(1) through (6). However, as noted above,
Method 29 analysis includes 17 individual analytes, including five that
are not listed HAPs (barium, copper, silver, thallium, and zinc) and
three that are not metals (arsenic, phosphorous and selenium).

AFS requests regulatory clarification or implementation guidance to
allow for the exclusion of Method 29 analytes that are not HAP metals
when demonstrating compliance with the optional total metal HAP
limitations in the rule. This will allow companies to use Method 29 to
make a demonstration but will provide the option to exclude analytes
that are not metal HAPs if those substances have a bearing on the
compliance demonstration.

In addition, Method 29 analyses yield concentration levels for each
metal HAP contained in a sample, and some individual HAPs metals may be
reported as being below analytical detection limits. AFS seeks
clarification as to how analyses of individual metal HAPs below
detection limits will be quantified with respect to demonstrating
compliance with the total metal HAPs limits. If each metal HAP analyzed
to be below detection limits is presumed to be present and accounted for
at the detection limit, the resulting total metal HAPs concentration
could potentially and erroneously be determined to exceed the total
metal HAPs limit. Accordingly, we request that EPA clarify in
implementation guidance that individual HAPs analyzed to be below
detection limits be considered as "zero" for purposes of determining
compliance with the total metal HAP emissions limits.

> **4. TEA Testing Alternative**

Section 63.7732(g)(v) of the final rule requires the use of Method 18
for demonstrating compliance with the cold box mold or core making line
triethylamine ("TEA") standard of one (1) ppmv. Because Method 18 has a
detection limit of 1 ppmv, compliance determinations may be problematic
using the procedure described in the method. Therefore, it is likely
that operators will elect to use the alternative included in section
8.2.4 of Method 18, *i.e.*, a silica gel adsorption tube sampling
technique. Since that Method 18 alternative methodology is consistent
with NIOSH Method 2010, with which some companies may have greater
familiarity, AFS requests that EPA provide language in the rule that
also identifies the NIOSH method as an acceptable alternative.

F.  **Continuous Parameter Monitoring Systems (CPMS)**

> **1. CPMS Data Availability**

Section 63.7741(f) describes data requirements for CPMS, and paragraph
(f)(2) states that "each CPMS must have valid hourly data for 100
percent of every averaging period." We interpret this to mean simply
that any data set used to compute averages must not have any missing
data for the averaging period. However, the language could be
misinterpreted to mean that CPMS must provide valid data 100 percent of
the time. Such an interpretation would be unreasonable and unrealistic
and fails to recognize the reality of inevitable malfunctions that may
be associated with CPMS monitoring equipment. Accordingly, AFS requests
clarification of the language in § 63.7741(f)(2) to avoid any
misinterpretation.

**2. Damper Position Monitoring**

Section 63.7740(a)(2) requires daily visual checks of VOHAP capture
system damper positions for dampers that are manually set and intended
to remain in the same position. AFS believes this is an unnecessary and
burdensome monitoring and inspection procedure for manually set and
fixed damper positions. We believe it is sufficient to include
inspection of such dampers during monthly preventive maintenance
inspections and request a modification of the rule to establish this
monitoring frequency.

**3. Baghouse Compliance Monitoring Requirements**

Section 63.7740(b) contains extensive requirements for monitoring and
inspecting baghouse systems. We believe the extent and frequency of
these requirements are unnecessary and unduly burdensome and go beyond
those requirements necessary to ensure effective operation. These
include [daily]{.underline} monitoring or inspections for baghouse
pressure drop and compressed air supply and pressure for pulse-jet
baghouses, [weekly]{.underline} inspections to ensure that dust is being
removed from baghouse hoppers, [monthly]{.underline} inspections of bag
cleaning mechanisms and bag tension; and [quarterly]{.underline}
inspections of baghouse physical integrity and fan conditions.

AFS understands the need for periodic monitoring and inspection of
baghouse system components and operating parameters, but we believe the
requirements in the rule are inflexible and too prescriptive. Moreover,
the requirements do not necessarily comport with manufacturer
recommendations for inspection and maintenance of system components.

We request that EPA modify the rule to allow for baghouse monitoring
requirements to be incorporated into the O&M plans required in
§ 63.7710(b). By incorporating baghouse monitoring and inspection into
O&M plans, companies can tailor their plans to the needs of the system
and incorporate manufacturer recommendations for inspection, inspection,
replacement, and repair. Further, as noted in § 63.7710(b), O&M plans
are "subject to approval by the Administrator", which provides the
opportunity for adequate oversight by the delegated authority.

> **G. Operating Parameters and Corrective Action**

1.  **Provisions Relating to Cupola "Blast"**

Several provisions of the rule refer to cupola blast conditions. For
example, § 63.7690(b)(3) requires that the cupola afterburner be
operated such that the combustion zone temperature does not fall below a
1,300^o^F average except for \"periods when the cupola is off blast and
for 15 minutes after going on blast.\" Also, § 63.7732(b)(3) and (c)(3)
require that sampling be conducted \"only during times when the cupola
is on blast.\"

The industry is concerned that the term \"on blast\" is not defined
within the rule or discussed in the preamble and could be misinterpreted
to mean [any]{.underline} period when \"blast\" air is entering the
cupola. This is problematic because blast air is often used during
periods when melting is not occurring, such as preparing the cupola for
operation. Typically, a cupola must be properly prepared before melting
can commence. The procedure is initiated by building a sand bed in the
bottom of the furnace. A bed of coke is then added and ignited, commonly
utilizing blast air, and is allowed to burn for approximately one hour.
When the coke bed is established and the cupola furnace is at the proper
temperature, the blast air is turned off while the furnace is charged
with metal, coke, and limestone. After the cupola furnace is fully
charged, the blast air is again introduced and the melting process
begins. It is neither necessary nor appropriate to maintain a 1,300^o^F
afterburner temperature during startup periods when blast air is used as
described and the gas stream lacks an adequate concentration of carbon
monoxide (CO) to sustain combustion. Neither is it appropriate to
include these startup periods in performance tests. Stated another way,
operating parameters and testing should apply only when blast air is
being introduced to the cupola furnace [and]{.underline} the furnace is
capable of producing molten metal. This interpretation is consistent
with provisions relating to electric arc and electric induction
furnaces, which specify sampling "only when metal is being melted."
*See* § 63.7732(b)(4) and § 63.7732(c)(4).

The use of blast air in the situations described can be defined in the
facility's startup, shutdown, and maintenance ("SSM") plan and thus not
be subject to the rule's emission limitations during these periods.
However, AFS is concerned that unless these exceptions are expressly
stated, the rule may be misinterpreted or misapplied. For this reason,
AFS requests that the phrase "except as provided for in the startup,
shutdown and maintenance plan" be added to § 63.7690(b)(3) and
§ 63.7732(b)(3) and (c)(3).

2.  **Operating Parameters As a Basis for Taking Corrective Action**

The rule requires that operating limits be established during
performance testing for each capture system and control device. These
operating parameters may consist of pressure drop and water flow rates
for wet scrubbers, flow rates for acid scrubbers, or temperature for
combustion devices. Foundries are required to operate within the
established operating limits at all times. Section 63.7765 defines a
"deviation" to include "any instance in which an affected source ...
fails to meet any requirement or obligation ... including operating
limits."

AFS believes that operating parameters established during performance
testing should only be a basis for taking corrective action and should
not be considered to be deviations unless corrective action is not
taken. As EPA has noted in its proposed Primary Aluminum MACT rule:

> ... a change in a control device's operating parameter does not
> directly correlate with an increase in emissions and does not provide
> a reasonable assurance that the emission limitation was exceeded when
> the parameter changed. In other words, the operating parameter may be
> outside the limit established during the performance test while
> emissions are still below the applicable limit. The primary value of
> monitoring the control device parameters is to detect a potential
> problem with the device's operation as soon as possible and to
> promptly investigate and correct the cause.

61 Fed. Reg. 50590. Moreover, within the Foundry MACT rule itself, this
concept is embodied in the requirements for bag leak detection systems,
which are employed in lieu of operating parameters relevant to fabric
filter installations.

In addition, exceedances of operating parameters should not be
considered deviations unless corrective action is not taken or is not
successful in correcting operating problems. As EPA notes in the Coke
Oven MACT rule:

> If the corrective action is not successful, the owner or operator must
> take additional corrective actions. If the second attempt to fix the
> problem is not successful, the failure must be reported as a
> deviation.

68 Fed. Reg. 18009. Such phased corrective action steps are also
consistent with those specified in the Foundry MACT rule for bag leak
detection indications.

Finally, AFS is concerned that in the absence of clarifying language a
deviation from an operating limit or parameter could be considered a
"violation." To address this concern, we direct your attention to the
following language in the recently signed MACT rule for Industrial
Boilers and Process Heaters[^6], which states,

> A deviation is not always a violation. The determination of whether a
> deviation constitutes a violation of the standard is up to the
> discretion of the entity responsible for enforcement of the standards.

For these reasons, AFS requests that the rule be amended to clarify that
departures from control device operating parameters are not operating
"limits" but instead are operating parameters that serve as a basis for
triggering corrective action. We also request that clarifying statements
be inserted into the rule to provide for sequenced corrective action
steps for all operating parameter exceedances consistent with the
approach for bag leak detectors. In addition, we request the addition of
language, consistent with the Industry Boiler and Process MACT,
clarifying that deviations from control device operating limits or
parameters are not presumptively deemed violations but are instead
subject to enforcement authority discretion.

3.  **Conformance of Operating Parameters with Performance Testing
    Provisions**

Sections 63.7690(b)(2), (4), and (5) require foundries to operate
control devices for regulated units such that the 3-hour averages of
relevant parameters (scrubber pressure drop, water or scrubbing liquid
flow rate, or temperature) do not fall below minimum levels established
during performance testing. Section 63.7733(b), (c), and (d) also
require foundries to establish site-specific operating limits based on
3-hour averages for each sampling run in which the applicable emissions
limit is met. Finally, § 63.7741(f)(3) requires CPMS to be capable of
recording 3-hour averages.

These requirements are inconsistent with performance testing
requirements. Although sampling times specified in performance testing
requirements are in some cases three hours in duration, other
performance testing sampling durations are based upon sampling volumes
which do not correspond to a three-hour duration (*e.g.*, § 63.7732(b)
and (c)) or have minimum sampling times of one hour *(e.g.*, § 
63.7732(g)). This discrepancy could be erroneously interpreted to
require performance testing over a period of at least three hours when
the specific performance testing requirements do not require tests of
that duration.

AFS requests that the rule be amended to remove references to 3-hour
averages for operating parameters and instead insert language that would
establish operating parameters consistent with observed parameters, and
corresponding to applicable test methodology, for any test run during a
performance test demonstrating compliance with the applicable emission
limit.

> **H. Reporting of SSM Plan Inconsistencies**

Section 63.7751(c) requires submittal of an immediate SSM report
whenever a source has a startup, shutdown, or malfunction event that is
not consistent with the prepared SSM plan. However, this requirement is
not consistent with current NESHAP General Provisions at
§ 63.10(d)(5)(ii), which requires an immediate report only if the action
taken is not in conformance with the source's SSM plan [and]{.underline}
if "the source exceeds any applicable emission limitation in the
relevant emission standard." Although every effort is made to plan for
startup, shutdown, and malfunction events, it is not possible to
anticipate all exigencies. However, some aspects of these events may
have no effect on emissions or compliance with emission standards, and
"immediate" notification is not reasonable or necessary.

AFS requests modification of the language in the rule to duplicate or
refer to the relevant NESHAP General Provisions language regarding
reporting of SSM events that are inconsistent with SSM plans. We believe
is it sufficient to report SSM plan departures that have no emission
consequences in semi-annual compliance reports.

> **I. Recordkeeping**

Section 63.7752(a)(4) requires records of the annual quantity of each
chemical binder and coating material used to make molds and cores and
"the annual quantity of HAP used at the foundry." While the intent of
the latter phrase is to apply to HAPs contained in the chemical binders
and coating materials used in molds and cores, the language could be
misinterpreted to require recordkeeping for all HAP materials used at
the foundry.

AFS requests modification of § 63.7752(a)(4) by adding the phrase "for
these purposes" to make clear that HAPs recordkeeping applies only to
binders and coating materials used in making molds and cores.

J.  **Basis for Major Source Status**

As described in § 63.7681, an iron or steel foundry is a "major source"
of HAPs "if it emits or has the potential to emit ... or is located at a
facility that emits or has the potential emit..." HAPs above the
statutory threshold limits. Section 112(a)(1) of the Clean Air Act and
§ 63.2 of the NESHAP General Provisions define a major source to
encompass "any stationary source or group of stationary sources [located
within a contiguous area]{.underline}." (Emphasis added.) Section 63.2
also defines "affected source" to encompass "the collection of
equipment, activities, or both [within a single contiguous
area]{.underline}." (Emphasis added.) While we therefore believe the
meaning of a facility in the context of § 63.7681 is unambiguous, AFS
members have experienced interpretations by some regulatory authorities
who have deemed non-contiguous and geographically separated facilities
owned by the same company to be a single facility for purposes of "major
source" determinations. Accordingly, we request that EPA issue
implementation guidance to make clear to delegated authorities that
non-contiguous facilities are not additive for purposes of major source
determinations.

\-\--

We strongly urge EPA to take the necessary administrative action to make
the changes requested. We look forward to a timely response to this
petition, and representatives of AFS stand ready and willing to meet
with EPA staff at your convenience to clarify our comments or elaborate
on their importance. Please have your appropriate staff contact Gary
Mosher (800-537-4237 Ext. 228 or <gem@afsinc.org>) or John Wittenborn
(202-342-8514 or jwittenborn@colliershannon.com) with questions or to
make arrangements for further discussion.

Sincerely,

![](media/image1.png){width="3.182638888888889in"
height="0.8694444444444445in"}

John L. Wittenborn

Counsel to American Foundry Society

cc: Steve Fruh

Jeffrey R. Holmstead

Gary Mosher

[^1]: *See* Comments of American Foundry Society, Docket ID No.
    OAR-2002-0034-0046, February 21, 2003.

[^2]: *See* "National Emission Standard for Hazardous Air Pollutants for
    Iron and Steel Foundries -- Background Information for Proposed
    Standard," Docket ID No. OAR-2002-0034-0001, December 2002.

[^3]: *See* "National Emission Standards for Hazardous Air Pollutants
    (NESHAP) for Iron and Steel Foundries -- Background Information for
    Promulgated Standards," Docket ID No. OAR-2002-0034-0144, August
    2003.

[^4]: *See* "Fabric Filter Bag Leak Detection Guidance,"
    EPA-454/R-98-015, September 1997.

[^5]: *See* 40 C.F.R. 60, Subpart AA.

[^6]: The rule has not yet been published but is accessible on EPA's
    website. *See* www.epa.gov/ttn/atw/boiler/boilersfinalrule.pdf.