Document ID: EPA-HQ-OAR-2002-0034-0234
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-04-17T04:00Z

Alliance of Automobile Manufacturers

Petition for Reconsideration

national emission standards for hazardous air pollutants

iron & steel foundries

Final Rule

(69 Fed. Reg. 21906, april 22, 2004)

Submitted to:

Michael O. leavitt, administrator

u.s. environmental protection agency

June 21, 2004

Table of Contents  TOC \o "1-4" \h \z \u  

  HYPERLINK \l "_Toc75613489"  I.	Introduction	  PAGEREF _Toc75613489 \h
 1  

  HYPERLINK \l "_Toc75613490"  II.	Standard of Review For Petitions for
Reconsideration	  PAGEREF _Toc75613490 \h  3  

  HYPERLINK \l "_Toc75613491"  III.	Background	  PAGEREF _Toc75613491 \h
 4  

  HYPERLINK \l "_Toc75613492"  A.	Basic Processes in an Iron Foundry	 
PAGEREF _Toc75613492 \h  4  

  HYPERLINK \l "_Toc75613493"  B.	Characteristics of a Typical Cupola	 
PAGEREF _Toc75613493 \h  6  

  HYPERLINK \l "_Toc75613494"  C.	Metal HAP emissions from Cupolas
Represent a Minor Portion of Total HAP Emissions from the Melting
Operations	  PAGEREF _Toc75613494 \h  7  

  HYPERLINK \l "_Toc75613495"  IV.	EPA Has The Authority To Establish
Separate Categories, Subcategories, or Standards Under Section 112 So As
To Best Serve The Intent Of The Clean Air Act	  PAGEREF _Toc75613495 \h 
8  

  HYPERLINK \l "_Toc75613496"  A.	EPA Has Broad Authority to Establish
Categories and Subcategories	  PAGEREF _Toc75613496 \h  8  

  HYPERLINK \l "_Toc75613497"  V.	Factual Support For Establishing A
Separate Category, Subcategory or Standard for Cupolas Controlled with
Wet-Scrubbers	  PAGEREF _Toc75613497 \h  10  

  HYPERLINK \l "_Toc75613498"  A.	The Final Foundry NESHAP Results in an
Overall Increase in Air Emissions & Thus Creates an Environmental
Disbenefit	  PAGEREF _Toc75613498 \h  10  

  HYPERLINK \l "_Toc75613499"  1.	Removal of Wet Scrubbers will Result
in an Increase of Over 800 Tons of Emissions	  PAGEREF _Toc75613499 \h 
13  

  HYPERLINK \l "_Toc75613500"  2.	Emission Increases Resulting from
Increased Electricity Demand Will be No Greater than 94.7 Tons and the
Net Reduction in SO2 Emissions from Creating A Separate Standard for Wet
Scrubber-Controlled Cupolas Would Be 715 Tons	  PAGEREF _Toc75613500 \h 
17  

  HYPERLINK \l "_Toc75613501"  3.	Establishing a MACT Floor for Existing
Cupolas with Wet Scrubbers	  PAGEREF _Toc75613501 \h  18  

  HYPERLINK \l "_Toc75613502"  4.	The Resulting SO2 Increase Outweighs
The Potential PM Decrease	  PAGEREF _Toc75613502 \h  21  

  HYPERLINK \l "_Toc75613503"  5.	Summary of SO2 and PM Calculations and
Comparison with Lime Manufacturing NESHAP	  PAGEREF _Toc75613503 \h  22 

  HYPERLINK \l "_Toc75613504"  6.	Creating a Separate Standard or
Establishing a Separate Subcategory for Existing Facilities Operating a
Wet Scrubber-Equipped Cupola Would Result in an Air Quality Bonus by
Reducing  PM2.5 Emissions	  PAGEREF _Toc75613504 \h  23  

  HYPERLINK \l "_Toc75613505"  7.	EPA Should Either Create Separate
Standards or Create a Separate Subcategory for Cupolas Equipped with Wet
Scrubbers in order to Account for the Superior SO2 and Fine Particulate
Performance of Wet-Scrubbers	  PAGEREF _Toc75613505 \h  25  

  HYPERLINK \l "_Toc75613506"  B.	Cupolas with Wet Scrubbers Are Not
Similar Sources To Cupolas with Baghouses & Should Be Regulated Under a
Separate [Sub]Category or Standard	  PAGEREF _Toc75613506 \h  27  

  HYPERLINK \l "_Toc75613507"  1.	Wet Scrubber Systems Are An Integral
Part of the Process	  PAGEREF _Toc75613507 \h  27  

  HYPERLINK \l "_Toc75613508"  2.	Large or Multiple Cupola Facilities
with Wet Scrubber Operations Are Unique and Should Be Regulated Under a
Separate [Sub]Category or Standard	  PAGEREF _Toc75613508 \h  29  

  HYPERLINK \l "_Toc75613509"  3.	The Emission Characteristics from a
Wet Scrubber Contain Significantly Less Acid Gas than Emissions from a
Baghouse	  PAGEREF _Toc75613509 \h  31  

  HYPERLINK \l "_Toc75613510"  4.	Replacement of a Wet Scrubber With a
Baghouse Involves Extensive Redesign and Re-engineering of the Process	 
PAGEREF _Toc75613510 \h  31  

  HYPERLINK \l "_Toc75613511"  C.	Calculation of An Emission Limitation
for the Wet Scrubber Category & Subcategory	  PAGEREF _Toc75613511 \h 
33  

  HYPERLINK \l "_Toc75613512"  1.	Emission Limitation for the Category
of Existing Cupolas with Wet Scrubbers	  PAGEREF _Toc75613512 \h  33  

  HYPERLINK \l "_Toc75613513"  2.	Emission Limitation for the
Subcategory of Existing Multiple, Large Co-located Cupolas with Wet
Scrubbers	  PAGEREF _Toc75613513 \h  33  

  HYPERLINK \l "_Toc75613514"  VI.	Conclusion	  PAGEREF _Toc75613514 \h 
39  

 Table of Tables

  TOC \h \z \c "Table"    HYPERLINK \l "_Toc75613632"  Table 1:	SO2
Avoided by Accomodating Wet Scrubbers on Existing Cupolas	  PAGEREF
_Toc75613632 \h  15  

  HYPERLINK \l "_Toc75613633"  Table 2:  Increase in PM Per Emission
Group	  PAGEREF _Toc75613633 \h  22  

  HYPERLINK \l "_Toc75613634"  Table 3:  Changes in PM & SO2 Emissions
Resulting from NOT Replacing WS with BH	  PAGEREF _Toc75613634 \h  23  

  HYPERLINK \l "_Toc75613635"  Table 4:  Summary of Net Changes In PM	 
PAGEREF _Toc75613635 \h  25  

  HYPERLINK \l "_Toc75613636"  Table 5:  Summary of SO2 Data for Cupolas
Equipped with Baghouses	  PAGEREF _Toc75613636 \h  31  

  HYPERLINK \l "_Toc75613637"  Table 6:  Summary of SO2 Data for Cupolas
Equipped with Wet Scrubbers	  PAGEREF _Toc75613637 \h  32  

  HYPERLINK \l "_Toc75613638"  Table 7:  Existing Operations with
Multiple Cupolas Equipped with Wet Scrubbers	  PAGEREF _Toc75613638 \h 
34  

  HYPERLINK \l "_Toc75613639"  Table 8:  Test Data for the Large Source
Category of Existing Cupolas with Wet Scrubbers	  PAGEREF _Toc75613639
\h  36  

  HYPERLINK \l "_Toc75613640"  Table 9:  Statistical Evaluation of the
Stack Test Runs	  PAGEREF _Toc75613640 \h  38  

 Table of Figures

  TOC \h \z \c "Figure"    HYPERLINK \l "_Toc75604719"  Figure 1:
Overview of Foundry Operations 	  PAGEREF _Toc75604719 \h  5  

  HYPERLINK \l "_Toc75604720"  Figure 2:	Diagram of a Basic Cupola
Operation	  PAGEREF _Toc75604720 \h  7  

  HYPERLINK \l "_Toc75604721"  Figure 3:	The Foundry Rule Results in an
Overall Increase in Emissions	  PAGEREF _Toc75604721 \h  12  

  HYPERLINK \l "_Toc75604722"  Figure 4:	Ratio of Fine PM Decrease to
Coarse PM Increase	  PAGEREF _Toc75604722 \h  18  

  HYPERLINK \l "_Toc75604723"  Figure 5:	Diagram of Cupola & Wet
Scrubber System	  PAGEREF _Toc75604723 \h  30  

  HYPERLINK \l "_Toc75604724"  Figure 6:	Illustration of Natural Break
Points in Wet Scrubber Category Based on Size	  PAGEREF _Toc75604724 \h 
35  

  HYPERLINK \l "_Toc75604725"  Figure 7:	Graph of Stack Test Runs from 3
Largest Sources	  PAGEREF _Toc75604725 \h  36  

 

BEFORE THE ADMINISTRATOR

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

____________________________________

 						:

						:

In re National Emission Standards for	:

Hazardous Air Pollutants for Iron and	:		Docket No. OAR-2002-0034

Steel Foundries; 69 Fed. Reg. 21906, 	:

April 22, 2004				:

						:

						:

____________________________________:

PETITION FOR RECONSIDERATION

The Alliance of Automobile Manufacturers (the “Alliance”)
respectfully submits this Petition for Reconsideration (“Petition”)
of the National Emission Standards for Hazardous Air Pollutants
(“NESHAP”) for Iron and Steel Foundries, Final Rule, 69 Fed. Reg.
21906, April 22, 2004.  The Alliance is a trade association composed of
nine car and light truck manufacturers.  Alliance members account for
more than 90 percent of U.S. vehicle sales.  Several member companies
operate iron foundries in the U.S. and are directly impacted by this
final NESHAP for Iron and Steel Foundries.  

Introduction

The U.S. Environmental Protection Agency (“EPA” or “Agency”)
promulgated the National Emission Standards for Hazardous Air Pollutants
for Iron and Steel Foundries,” (“Foundry Rule” or “Foundry
MACT”) 69 Fed. Reg. 21906 (April 22, 2004).  The Alliance submitted
detailed comments during the public comment period for the proposed
rulemaking.  However, additional information has become available which
supports the Alliance’s position that existing cupola operations that
are equipped with wet-scrubbers should be regulated as a separate source
category or subcategory, or under a separate standard.

The final Foundry MACT sets an emission limitation for cupola operations
of 0.006 grains (“gr”) of particulate matter (“PM”) per dry
standard cubic feet (“dscf”) of exhaust.  The vast majority of
existing cupola operations already control emissions of air pollutants
with either wet-scrubber technology or the use of fabric filters (also
known as bag-houses).  In general, both wet-scrubbers and fabric filters
are highly effective at controlling emissions of PM.

According to the EPA’s Background Information Document (“BID”) for
the proposed rule, the primary control option for cupola’s is to
replace venturi scrubbers with fabric filters.  The implication is that
in order to assure compliance with the emission standard for PM many
existing foundries currently utilizing wet-scrubber control technology
will be faced with the hardship of having to remove that technology,
redesign and re-engineer the entire melting operation (likely including
replacing the cupola itself and possibly even the process flow of the
facility) to accommodate the much larger and very costly dry fabric
filter system.  EPA estimated that this would result in a reduction in
HAP metal emissions of only 64 tons per year.  

Information in this petition will describe in detail why cupolas that
operate with wet-scrubbers are fundamentally different from cupolas that
exhaust through fabric filters.  These differences are apparent from not
only an engineering/process perspective but also based on the
constituents in their exhaust gas streams.   

Further, the emission reduction resulting from the use of fabric filters
and the emission reductions resulting from the use of wet scrubbers
should not be evaluated solely on the basis of the reduction in
emissions of one class of air pollutant.  Instead, the overall
environmental benefit and detriment of each control strategy should be
taken into account.  So, for example, although fabric filters may be
slightly more efficient at removing particulate matter, wet scrubbers
not only remove particulate matter from exhaust streams, but acid gases
such as SO2 as well.  In light of these countervailing differences in
performance, it is impossible to say whether existing cupolas equipped
with wet scrubbers or existing cupolas equipped with fabric filters are
the “best performing” within the meaning of 42 U.S.C. §
7412(d)(3)(A), CAA § 112(d)(3)(A).

For these reasons, the Alliance requests that the Agency amend the Iron
and Steel Foundry NESHAP to establish a separate standard for existing
foundries with cupolas equipped with wet scrubbers.  More specifically,
the Alliance requests that, for purposes of the existing source MACT
standard for cupolas, EPA create two categories (or subcategories)
and/or two emission standards – one for cupolas with wet-scrubbers and
the other for cupolas equipped with fabric filters.  

The emission standard proposed in this Petition is for existing
foundries with cupolas equipped with wet scrubbers to be 0.05
grains/dscf total particulates with an option for the owner or operator
of the facility to substitute an equivalent limit of total metallic HAP
emissions of 0.004 grains/dscf from the cupola emission stacks.  

In addition, to separating existing cupola operations with wet scrubbers
from those with fabric filters, this Petition provides evidence
supporting the establishment of a further subcategory for existing
large, multiple cupola “affected sources” that are equipped with
wet-scrubbers.  Based on EPA’s own information, there are critical
factors that differentiate these large, multiple cupola operations from
all other iron foundries.  The emission standard for these existing,
large, multi-cupola operations should be established at 0.052 gr
PM/dscf.

For the reasons set forth in this petition, the Alliance respectfully
requests that the Administrator convene a proceeding to reconsider the
Iron and Steel Foundry NESHAP.  Specifically, the Alliance proposes that
the Iron and Steel Foundry NESHAP be amended to provide a separate
subcategory for existing cupola operations equipped with wet-scrubbers. 
Further, the Alliance proposes that the existing source wet-scrubber
category then distinguish the large, multiple cupola operations in this
category from the other existing cupola operations.  

Creation of these subcategories are consistent with the EPA’s
statutory authority under Section 112 of the Clean Air Act (“CAA” or
“Act”).  Moreover, establishment of these separate standards are
fully justified on the grounds that by recognizing the differences
cupolas with wet-scrubbers from those with fabric filters and
establishing separate emission limits, the end result will be a greater
reduction in air pollution than will otherwise be achieved through the
current version of the rule.  Thus, this proposal is environmentally
beneficial and in the best interest of protecting public health and
welfare.   

Standard of Review For Petitions for Reconsideration

Section 307(d)(7)(B) of the Clean Air Act requires the Administrator to
convene a proceeding to reconsider a final rule if it is demonstrated,
within the time specified for judicial review, that an issue of central
relevance to the outcome of the rule was impracticable to raise, or if
the grounds for the objection arose after the public comment period. 
Specifically, Section 307(d)(7)(B) provides, in part:

If the person raising an objection can demonstrate to the Administrator
that it was impracticable to raise such objection within such time or if
the grounds for such objection arose after the period for public comment
(but within the time specified for judicial review) and if such
objection is of central relevance to the outcome of the rule, the
Administrator shall convene a proceeding for reconsideration of the rule
and provide the same procedural rights as would have been afforded had
the information been available at the time the rule was proposed. . 
(emphasis added)

The issue of central relevance to the outcome of the rule that is the
basis of this Petition is that existing cupola operations controlled
with wet-scrubber technology were considered in the rulemaking as
similar enough to cupola operations controlled with fabric filters that
they were grouped together for purposes of establishing the MACT floor
for these operations.  However, the evidence is incontrovertible that
cupolas equipped with wet-scrubbers are inherently and substantially
different from cupolas equipped with fabric filters. 

Moreover, the promulgation of a separate standard for existing cupolas
that are equipped with wet scrubbers, is based partly on the action EPA
took in promulgating the NESHAP for Lime Manufacturing Plants (“Lime
NESHAP”).  Since the Lime NESHAP was not published in the federal
register until January 5, 2004, almost a full year after the deadline
for submitting comments on the Foundry Rule, it was impracticable to
comment on this issue during the public comment period for the Foundry
MACT.  

More specifically, the Lime NESHAP established an important precedent by
creating separate standards within a source category for existing
sources using wet scrubbers and another standard for sources using
baghouse technology.  The concept of separate standards within a
subcategory and the factual basis for the conclusion that separate
standards were appropriate in the Lime NESHAP provided key information
regarding the importance of maintaining existing SO2 controls for
purposes of not only controlling acid gases, but also for purposes of
controlling precursors to fine particulate.  The basis for the separate
standard for the wet scrubber controlled operations in the Lime NESHAP
established a new basis for accommodating wet scrubbers on existing
cupolas.    

The Administrator has the authority to reconsider the final Foundry Rule
and, because allowing the rule to stand as it is will result in an
overall increase in air emissions, the EPA should re-evaluate the
provisions of the rule to accommodate wet scrubber technology on
existing cupolas.

Background

Basic Processes in an Iron Foundry

In the proposed rule, the EPA describes Iron and Steel foundries as
operations that: 

manufacture castings by pouring molten iron or steel melted in a furnace
into a mold of a desired shape.  The primary processing units of
interest at iron and steel foundries because of their potential to
generate HAP emissions are: metal melting furnaces; scrap preheaters;
pouring areas; pouring, cooling, and shakeout lines; mold and core
making lines; and mold and core coating lines.  

  REF _Ref75126980 \h  Figure 1  illustrates the basic processes at most
foundries.  Of the six primary processing units at iron and steel
foundries, only one – (existing) metal melting furnaces (equipped with
wet scrubbers) -- are the subject of this petition. 

Figure   SEQ Figure \* ARABIC  1 :  Overview of Foundry Operations 

Three types of furnaces can be used to melt iron in a foundry:  1)
cupolas; 2) electric arc furnaces; and 3) electric induction furnaces.. 
EPA describes a cupola as a:

vertical cylindrical shaft furnace that uses coke and forms of iron and
steel, such as scrap and foundry returns, as the primary charge
components.  The iron and steel are melted through combustion of the
coke by a forced upward flow of heated air.  Cupolas are equipped with
afterburners downstream from the charge to incinerate carbon monoxide
(CO), which is a major byproduct of coke combustion.  Some of the coke
used to fuel the cupola also becomes part of the molten metal, thereby
raising the carbon content of the molten metal. 

The proposed Foundry NESHAP goes on to describe that there are some
differences between cupolas based on the method of charging:

In one configuration, termed above charge gas takeoff, charging is done
through a door in the shaft above the level of the charge. 
Alternatively, in the below charge gas takeoff configuration, the flow
of gas is taken from an opening in the side of the shaft below the level
of the charge.  The latter configuration is more typical of modern
cupolas. In either case, the offgas may be directed through a heat
exchanger to transfer heat to the inlet air for energy conservation. 
The Wet Scrubber is an Integral Part of the Cupola. (emphasis added.)

Regardless of whether it is an above or below charge operation, nearly
all the emissions are exhausted through a furnace stack.  The exhaust
stream contains particulate matter (“PM”), organic compounds, and
carbon monoxide (“CO”).  The HAPs in the PM are by mostly lead and
manganese, but cadmium, chromium, and nickel would also be expected in
the exhaust stream since they are generally impurities in the scrap
metal that is used as raw material in the cupola.  The organic HAP are
primarily products of incomplete combustion.  Most cupolas exhaust to
either baghouses or wet scrubbers to control emissions of PM.  

Characteristics of a Typical Cupola

  REF _Ref75293769 \h  Figure 2  illustrates the key parts of a typical
cupola.  A cupola equipped with a wet scrubber would look similar to the
diagram below.  In fact, if the diagram continued upward a bit it would
show the wet-cap which is the first step in the wet scrubber process. 
The wet cap is effectively a water wash that knocks out the larger
particles before the gas stream continues through the process.

Figure   SEQ Figure \* ARABIC  2 :  Diagram of a Basic Cupola Operation

Metal HAP emissions from Cupolas Represent a Minor Portion of Total HAP
Emissions from the Melting Operations

It is important to note that the metal HAP emissions from cupolas make
up only a few percent of the total HAP emissions from melting
operations.  More specifically, the metal HAPs from melting operations
are estimated to make up only 3% of total HAP emissions.  The remainder
of the HAP emissions are organic, not metal.  These organic emissions
are destroyed by combustion as they pass through an afterburner prior to
being exhausted to the ambient air.  So, of the total HAP emissions from
the process, the final rule focuses on metal HAP emissions which make up
a small portion of the total emissions from the cupola.  

To further put the metal HAP emissions from cupolas into perspective, it
is important to note that of the nearly 600 iron and steel foundries in
the U.S., only 111 were identified by EPA as using cupola type furnaces
in their metal melting operations.  Thus, less than 20% of foundry
operations use cupolas to melt iron.  Of those operations, approximately
50% are controlled by wet scrubbers.  Moreover, the difference in
efficiency between baghouses and wet scrubbers is approximately only 2%.
 

Thus, the difference in efficiency between baghouses and scrubbers is
not only a mere 2%, but that small difference in efficiency represents a
difference in emissions from one of the smaller sources of PM in the
foundry, i.e., the melting operations.  In short, tearing out a wet
scrubber and replacing it with a baghouse will lead to tremendous
expense, but the resulting environmental benefit will be miniscule.

In summary, the metal emissions from cupolas being regulated by the
final rule represent only 3% of the total HAP emissions from the
cupolas, and cupolas only make up about 20% of the metal melting
operations across the country – with only about 50% of those currently
operating wet scrubbers..  So, the rule attempts to control 3% of the
emissions of HAPs, from about half of the 20% of the sources with
cupolas, by setting a standard based on the control efficiency of fabric
filters, which, in this case, have a control efficiency approximately 2%
greater than that of a well run wet scrubber.  Thus, even if the
existing final rule is left unchanged, the overall reduction in
emissions of metal HAPs will some fraction (~2% of total HAPs) of some
fraction (~50% of the ~20% of metal melting operations that are cupolas
with wet scrubbers).  The potential reductions in PM are not only
minimal, but they come at great cost – both economically to the
companies that have to implement a new control strategy, but also at
great cost to the environment since the replacement of the scrubbers
will result in an increase in emissions and the formation of other air
pollutants.  

EPA Has The Authority To Establish Separate Categories, Subcategories,
or Standards Under Section 112 So As To Best Serve The Intent Of The
Clean Air Act

EPA Has Broad Authority to Establish Categories and Subcategories

EPA has consistently asserted that the Agency has broad discretion to
establish categories and subcategories under Section 112.  For example,
in the NESHAP for Secondary Aluminum operations, EPA stated:

Subcategorization within a source category may be considered when there
is enough evidence to demonstrate clearly that there are significant
differences among the subcategories. The criteria to consider include
process operations (including differences between batch and continuous
operations), emission characteristics, control device applicability,
safety, and opportunities for pollution prevention.  (emphasis added)

EPA also strongly defended the Agency’s interpretation that Congress
granted broad discretion to establish categories and subcategories.  For
example, in the final NESHAP for plywood and other composite wood
materials, EPA asserted broad authority to define categories and
subcategories under Section 112(c).  In that rule, EPA established a
separate group of sources, identified as “low-risk” sources and
presented a methodology for that group to effectively be excluded from
regulation.  More specifically, EPA stated:

Moreover, while after 1990 we have principally used the traditional
criteria to define categories and subcategories, such use in general
does not restrict how we may define a subcategory in a specific case,
“as appropriate,” since each HAP-emitting industry presents its own
unique situation and factors to be considered. (See, e.g., Sierra Club
v. EPA, D.C. Cir. No. 02-1253, 2004 U.S. App. LEXIS 348 (decided Jan.
13, 2004).) Even assuming for argument that the language of section
112(c)(1) may initially appear to restrict our authority to define
subcategories, section 112(c)(1) cannot be read in isolation. 

* * *

There is no apparent reason why such a group or set of sources must be
limited to those defined by traditional categorization or
subcategorization criteria.  This is because, first, Congress in section
112(c)(1) clearly did not absolutely prohibit us from basing categories
and subcategories on other criteria generally…

So, in addition to the statutory provision allowing EPA to identify
subcategories (or additional categories or even establish separate
emission standards), EPA has provided some additional detail on the
types of factors to consider.  These include differences in process
operations, emission characteristics, applicability of control
technology, separate classes of units, operations, or other criteria
have an effect on air emissions from emission sources, or the
controllability of those emissions.  

Even more recently, the proposed amendments to the Hazardous Waste
Combustor NESHAP describes some factors EPA considered when deciding it
was appropriate to subcategorize certain sources under the rule.  

CAA section 112(d)(1) allows us to distinguish amongst classes, types,
and sizes of sources within a category when establishing floor levels. 
Subcategorization typically reflects ‘‘differences in manufacturing
process, emission characteristics, or technical feasibility.’’  See
67 FR 78058.  A classic example, provided in the legislative history to
CAA 112(d), is of a different process leading to different emissions and
different types of control strategies—the specific example being
Soderberg and prebaked anode primary aluminum processes.  See ‘‘A
Legislative History of the Clean Air Act Amendments of 1990,’’ vol.
1 at 1138– 39 (floor debates on Conference Report).  If we determine,
for instance, that a given source category includes sources that are
designed differently such that the type or concentration of HAP
emissions are different we may subcategorize these sources and issue
separate standards. We have determined that it is appropriate to
subcategorize . . .

As will be described in further detail below, existing cupolas equipped
with wet scrubbers do represent “different” manufacturing processes.
 IN addition, they have different emission profiles, e.g., the fabric
filters do not control emissions of SO2.  Also, although it is
technically feasible to remove a wet scrubber and to retro-fit a
baghouse on a cupola, it is not a like-kind replacement of control
equipment.  The wet scrubber is an integral part of the manufacturing
process (e.g., it provides process heat and water where needed, etc.). 
So, although it is “feasible”, it is very costly to retrofit a
baghouse to a cupola.  In fact, it is generally less costly to replace
not only the wet scrubber, but to purchase a new cupola as well – one
that has been designed to work with the baghouse system.  Given the
differences in operation, size, and emission characteristics, existing
cupola operations with wet scrubbers should be regulated under a
separate [sub]category or emission limitation than existing cupolas with
baghouses.  

Factual Support For Establishing A Separate Category, Subcategory or
Standard for Cupolas Controlled with Wet-Scrubbers

The Final Foundry NESHAP Results in an Overall Increase in Air Emissions
& Thus Creates an Environmental Disbenefit

As promulgated, the Foundry Rule mandates that emissions from each
cupola metal melting furnace, at an existing iron and steel foundry,
limit emissions through a conveyance to the atmosphere to either 0.006
gr/dscf of particulate matter (PM), or alternatively, 0.0005 gr/dscf of
total metal HAP.  As recognized by EPA in the BID for this proposed
NESHAP, this emission limitation could effectively drive existing
foundries with cupola melting operations to replace their wet scrubber
control technology with a baghouse for PM control.  

Yet, from an environmental perspective, the amount of addition PM
control that will be gained from replacing wet scrubbers with baghouses
is nominal.  According to the experts in this field, the American
Foundry Society (“AFS”), the difference in particulate control
efficiency between the two technologies is a mere 2%.  Specifically, in
comments submitted on the proposed NESHAP for Iron and Steel foundries,
AFS stated:

Currently, wet collection systems are capable of achieving approximately
97.8 percent control of PM emissions. This compares to a collection
efficiency of about 99.8 percent for dry collection systems. As a
result, based upon the agency’s BID, the proposed NESHAP requirement
to effectively replace wet collection systems on cupolas with fabric
filter systems will reduce total HAP emissions by only 64 tons per year.

However, the use of wet scrubbers provides significant and important
environmental benefits.  Wet scrubbers are far more effective than
baghouses in reducing the emissions of acid gases, particularly sulfur
dioxide.  Establishing a separate standard for existing foundries with
cupolas using wet scrubbers to reduce sulfur dioxide emissions and
setting the PM limitations for those existing cupolas at 0.05 gr/dscf
would allow a significant number of existing wet scrubber systems to
remain in place (though most would probably require significant upgrades
to enhance their performance so as to assure compliance with the PM
emission limit).  

Thus, as illustrated in   REF _Ref75129123 \h  Figure 3 , although
replacement of the wet scrubbers with baghouse systems would result in a
decrease of approximately 375 tons of PM, there would also be an
unintended consequence of simultaneously over 800 tons of sulfur
dioxide.  Even assuming that the wet scrubbers use moderately more
energy than a baghouse, the direct increase in SO2 resulting from
removing wet scrubbers would far outweigh any reduction in SO2 that
could potentially result from the minor reduction in energy that could
result from switching to baghouses.  Adjusting the SO2 figure to reflect
the fact that wet scrubbers utilize more electricity than baghouses,
and, conservatively accounting for the reductions in emissions of sulfur
dioxide that would accompany the decrease in electricity used, the net
reduction in SO2 emissions would still be 715 tons.  

This represents a ratio of 1.91 to 1 of SO2 reductions to PM increases,
i.e., replacing the wet scrubbers would result in a net increase in
emissions of a criteria pollutant (SO2) – which is also a precursor to
PM-2.5 – greater than the net decrease in PM.  This “disbenefit”
ratio representing the increase in one pollutant for the decrease in
another, is even more disproportionate than the ratio in the Lime
Manufacturing NESHAP.  In the Lime NESHAP, where EPA determined that a
separate standard for scrubber-equipped lime kilns was justified, the
ratio was only 1.69 to 1.  Thus the case for establishing a separate
standard for existing cupola melting operations equipped with
high-efficiency wet scrubbers is even more compelling than that of the
Lime NESHAP.

Also, it is important to note that maintaining reductions in SO2 is
important not only because SO2 is a criteria air pollutant, but the
significant reduction in sulfur dioxide emissions that would follow from
the creation of a separate standard would result in cascading
environmental benefits by reducing the formation of fine particulates to
an even greater degree than was the case with the Lime Manufacturing
NESHAP.  

Figure   SEQ Figure \* ARABIC  3 :  The Foundry Rule Results in an
Overall Increase in Emissions

In addition, there are other real and significant benefits that although
they may not be precisely quantifiable at this time, would result from
the rule being modified so as to allow for the retention of wet scrubber
systems.  For example, although iron and steel foundries are not large
emitters of mercury, wet scrubbers more effectively reduce mercury
emissions than do baghouses.  While both wet scrubbers and baghouses do
a good job in removing particulates, including those particulates to
which some mercury becomes bound, while wet scrubbers do a far better
job in removing oxidized mercury that is contained in emissions.  The
precise balance of benefits depends on the proportion of
particulate-bound mercury and the proportion of oxidized mercury in a
particular emissions stream, [but the extraordinarily high temperatures
at which cupolas operate makes it likely that a relatively high
proportion of whatever mercury is in the emissions stream is oxidized.

For example, the average level of mercury (measured in terms of pounds
per hour) in the outlet from the wet scrubber treating the emissions
from a cupola at General Motors Saginaw facility was approximately 30.5%
lower than the level in the inlet to the wet scrubber.  By contrast, the
average level of mercury in the outlet from the bag house treating the
emissions from a cupola at Waupaca’s Tell City Foundry exceeded the
level measured in the inlet.   This is strongly suggestive that
baghouses are substantially less effective than wet scrubbers in
removing mercury from the emissions stream.  

Thus, the environmental benefits of retaining the wet scrubbers on
existing cupolas outweigh the nominal reduction in PM that may
potentially be realized if the Foundry NESHAP is implemented as
currently constructed.  To maximize environmental benefit, EPA should
determine MACT floors separately for existing facilities with cupolas
equipped with wet scrubbers and those not equipped with wet cupolas.

Removal of Wet Scrubbers will Result in an Increase of Over 800 Tons of
Emissions 

Available emission data illustrates the superior performance of wet
scrubbers compared to baghouses in the removal of SO2 from the emission
stream from cupolas.  Because SO2 is a gas (with little or no
condensation to fine particulates at the high temperatures
characteristic of emissions from cupolas to baghouse systems), the poor
performance of baghouses in removing SO2 is not surprising.  So,
although the primary reason many wet scrubbers were installed on foundry
cupolas in the first place was to control PM, the control of SO2 was,
and still is, a desirable side-effect.

Some of the best data regarding the efficiency of SO2 removal from wet
scrubbers versus baghouses comes from recent test reslts.  For example,
at the Waupaca Foundry (Plant 1) the exhaust stream coming form the
cupola is split -- one-third exhausts through a baghouse and two-thirds
pass through a wet scrubber.  This arrangement makes it possible to
directly compare the emissions from a baghouse and a wet scrubber when
the input to the treatment system from the cupola is identical.  

Test results show that the SO2 emissions rate from the wet scrubber is
94.78% less than that from the baghouse.  These test results prove with
great certainty that replacement of the wet scrubber with a baghouse
would result in an increase in the rate of SO2 emissions by more than 19
times.

Similarly, the Charlotte Pipe foundry (NC-05) replaced its wet scrubber
with a baghouse sometime between 1994 and 2000.  There is emission test
data from before the wet scrubber replacement and afterwards.  Comparing
the results of those two emissions tests indicates that the relative SO2
removal efficiency of the wet scrubber compared to the baghouse was
93.47%.  This result reinforces the reasonableness of the result of the
direct comparison at the Waupaca Foundry.  

In addition, in recent weeks both the Ford Motor Company and the General
Motors Corporation have performed testing to establish the rate at which
SO2 is removed by wet scrubbers at their facilities.  Ford’s scrubber
achieved an SO2 removal rate of 90.3%, and the GM scrubber achieved an
SO2 removal rate of 97.1%.  Taking the average of the Waupaca, Ford, and
GM removal rates yields an average removal rate of 94.06%.

It is important to note that the Ford data substantially understates the
actual removal efficiency of its system because the level of SO2 in the
input to the wet scrubber was measured after a wet quench, which is a
part of the wet scrubber treatment system and which would have to be
removed if the wet scrubber were to be replaced by a baghouse.  Assuming
that the wet quench removes approximately 30% of the SO2 in the
emissions stream, and that the wet scrubber itself then removes 90% of
the SO2 left in the emissions stream, then the overall SO2 removal is
93%.

To quantify the SO2 emissions increase that would result from the
replacement of the existing wet scrubbers by baghouses, the actual
removal rate, when known, was used.   For those facilities without test
data, a very conservative average removal rate of 94.06% was assumed.  
Table 1 shows the data and the calculations used in this analysis.  

Specifically, the removal efficiency was used to calculate an average
emissions rate per ton of production, using the data on emissions of SO2
from cupolas treated by wet scrubbers apparently used by EPA, updated
with additional historical data found by Ford and with the data
collected in recent weeks by Ford and GM, weighted by the tons per year
production reported in Appendix A to the Background Information Document
(2002) for each facility for which we have SO2 emissions data. 
Multiplying that weighted average emissions rate by 5,680,000 tons per
year, which is the production that would shift from treatment by wet
scrubbers to treatment by baghouses.  Then, converting the treatment of
cupola emissions from wet scrubbers to baghouses would result in the
emission of an additional 809.76  tons of SO2 from the affected cupolas.
 

In a draft memorandum from Jeff Coburn, RTI, to Kevin Cavender, EPA,
dated July 21, 2003, Mr. Cavender concluded that implementation of the
0.006 gr/dscf standard for particulate emissions from existing foundry
cupolas would result in an increase in emissions of SO2 from cupolas of
370 tons, with an offsetting decrease of 391 tons of SO2 from electric
power generation.   We believe that the conclusions reached by Mr.
Coburn in the draft memorandum with respect to both the magnitude of the
increase of SO2 emissions from cupolas and the offsetting decrease in
emissions from electric generating facilities are flawed.  

Table   SEQ Table \* ARABIC  1 :	SO2 Avoided by Accomodating Wet
Scrubbers on Existing Cupolas

	Cupolas with WS	 Production (t/y)	Post-Conversion

ID Number	Plant	SO2 (lb/ton)	Removal %

SO2 (lb/ton)	SO2 Decrease (tons)

784	NJ-04	0.0006	94.053	112,129	0.0101	0.53

77	MI-13*	0.0008	94.053	108,246	0.0126	0.64

254	WI-24	0.0015	94.053	101,000	0.0252	1.20

649	NJ-5	0.0020	94.053	100,000	0.0336	1.58

252	WI-42^1995	0.0023	94.053	205,118	0.0387	3.73

252	WI-42^1997	0.0097	94.053	205,118	0.1631	15.73

252	WI-42^1994	0.0110	94.053	205,118	0.1850	17.84

815	WI-01^1998	0.0060	94.780	103,458	0.1149	5.64

815	WI-01^*1994	0.0100	94.780	103,458	0.1916	9.39

710	MI-17*	0.0055	94.053	59,707	0.0925	2.60

314	NC-5	0.0150	94.053	157,075	0.2522	18.63

532	MO-05	0.0260	94.053	19,243	0.4372	3.96

688	PA-34	0.0610	94.053	49,331	1.0258	23.80

161	OH-47**	0.0099	97.100	1,305,407	0.3414	216.36

143	OH-46	0.0379	94.053	526,000	0.6365	157.44

 	Average	0.0133	 	 	 	 

 	Weighted Average Net Increase 

 	0.2851	 

 	Unweighted Average Increase	 	 	0.2488	 

TOTALS (weighted avg)	 	5,680,000	0.2851	809.76

TOTALS (unwgtd avg)	 	 	0.2488	706.67

TOTAL-facilities with both SO2 & PM Data	 	3,084,917	 	436.29

 

Facilities w/ Production>125,000	 	2,603,835	 	429.74

 

*Emissions reported as “less than.”  Data entered at ½ reported
value.

**Production adjusted downward to reflect non-cupola melting capacity. 
Site specific test data used

 

To assess the impact of implementing the 0.006 gr/dscf PM requirement
(which would require the replacement of wet scubbers with baghouses),
EPA developed emission factors for cupolas treated by baghouses, and
cupolas treated by wet scrubbers.  Those emission factors implicitly
assumed that the characteristics of the emissions from the two groups of
cupolas to the treatment systems were the same.  This analysis is faulty
given the enormous variability in SO2 emissions even among cupolas
treated by wet scrubbers.

Reported SO2 emissions vary from a low of 0.0006 lbs/ton of production,
to a high of 0.0610 lbs/ton of production – that is, by a factor of
100.  Enormous variability in the SO2 content of emissions to treatment
systems is also shown in the limited data from lime kilns.  For example,
in the Lime NESHAP, two emission factors from baghouse-treated lime
kilns were calculated; one was 2.60 lbs. SO2 per ton lime produced, and
the other was 48.0 lbs/ton.  For scrubbers, two other emission factors
were calculated – 1 lb/ton, and 0.21 lbs/ton.  

It is logical to assume that a higher proportion of facilities where
relatively high levels of SO2 emissions were expected or were actually
being experienced would have opted to install a treatment technology
(i.e., wet scrubbers) that addresses SO2 in strong preference to a
technology (i.e., baghouses) that does not.  Applying an emission factor
derived from those cupolas already treated by baghouses to the emissions
from cupolas currently treated by wet scrubbers to predict what those
cupolas would emit if their wet scrubbers to be replaced with baghouses
cannot be justified. 

  REF _Ref74952479 \h  \* MERGEFORMAT  Establishing a MACT Floor for
Existing Cupolas with Wet Scrubbers

In order to determine whether there is a solid case to be made for a
separate standard for all or some group of existing cupolas treated by
wet scrubbers (or, in the alternative, for a separate subcategory), a
comparison must be made between the SO2 increase that would be avoided
by creation of the separate subcategory and the decrease in PM that
would not be realized.  This evaluation requires first identifying the
appropriate PM emissions standard that would apply and thus estimate the
resulting emissions of PM.   

The starting point in this evaluation is to first determine what the
MACT Floor would be for existing cupolas equipped with wet scrubbers. 
According to a draft memorandum prepared by Jeff Coburn, RTI, for Kevin
Cavender, EPA, dated July 21, 2003, emissions information was available
for 71 cupolas controlled by venturi wet scrubbers.  In the Coburn
memorandum, Mr. Coburn takes 6% of 71, which is 4.3.  That memo states: 

[T]herefore, we evaluated the performance of the 4th and 5th best
performing units.  At the 99th percentile, these scrubbers achieved an
outlet PM concentration of 0.027 and 0.034 gr/dscf.  Consequently, it
appears that the MACT floor PM performance limit for cupola wet scrubber
systems is 0.03 gr/dscf.  

Coburn used the standard statistical technique EPA uses to move from an
average emissions concentration to a limitation reflecting a 99% degree
of confidence, but he also made a number of dubious assumptions. 

First, applying EPA’s typical approach to these facts, EPA would
generally look at the performance of the 5th best performing unit, since
that is the first unit that is performing at or below the 6% best
performance level.  The performance of the 4th best unit would not be
considered in setting the MACT floor since its performance is better
than the 94th percentile level.  The 5th best unit listed in EPA’s
database is Cupola D at the GM Saginaw facility.  The PM concentration
listed for this unit in that database is 0.021 gr/dscf.

Figure 4  summarizes the data showing that there is an even stronger
case for modifying this rule than there was in the Lime Manufacturing
NESHAP.  Here, the ratio of Fine PM decrease to Coarse PM increase that
would result from creating a separate standard for existing cupolas
equipped with wet scrubbers ranges from 2.28 : 1, all the way up to 4.06
: 1, compared with a ratio of 1.41 : 1 for the Lime Manufacturing
NESHAP. 

Emission Increases Resulting from Increased Electricity Demand Will be
No Greater than 94.7 Tons and the Net Reduction in SO2 Emissions from
Creating A Separate Standard for Wet Scrubber-Controlled Cupolas Would
Be 715 Tons

Because wet scrubbers use more electricity than do baghouses, the net
reduction in SO2 emissions as a result of adoption of our proposal for a
separate standard for existing wet scrubber-controlled cupolas must
reflect the effect that the increased demand for electricity would have
on SO2 emissions.  In a draft memorandum from Jeff Coburn, RTI, to Kevin
Cavender, EPA, dated July 21, 2003, Mr. Cavender concluded that the
additional electricity required to operate wet scrubbers compared to
baghouses would result in an increase in emissions of 391 tons of SO2.  

This estimate of 391 tons is unrealistic.  It is based on the national
average emissions rate of 6.04 lbs. of SO2 per MWhr, as reported in
Egrid 2002.  This emissions rate reflects the more than 50% share of
power generation from coal, which is a heavy emitter of SO2.  Coal-fired
power plants, and nuclear fueled power plants as well, are baseload
units.  They are generally operated around the clock.  If there is an
increase in demand for electricity, then peak-load and intermediate load
facilities will be operated more until there is enough new demand to
justify construction of another baseload plant.  Assuming that the
increase in generation would come from greater operation of existing
intermediate and peakload facilities, then the increase would be met by
oil- and natural gas-fired units.  Assuming that those units would be
operated in proportion to the use of those fuels in electric generation
is an extremely conservative assumption.  Using that assumption, 15.2%
of the increase would come from oil-fired generation, and 84.8% of the
increase would come from gas-fired generation. 

Using EPA’s assumption that wet scrubbers would use 129,600 MWh more
per year than would baghouses,  and using the emission rates for oil and
natural gas shown in Egrid 2002 (8.22 lbs/MWh for oil, and 0.25 lbs/MWh
for natural gas), the increase in SO2 that would be released from power
plants as a result of adoption of our proposal would be 94.7 tons per
year. 

Making the alternative assumption that new baseload facilities will be
constructed to meet, in part, the increased demand for electricity
attributable to the continued operation of existing wet scrubbers, it is
most likely that the long-term growth in demand would be met almost
entirely by the construction of new gas-fired facilities.  It has been
the case for the last twenty years or so that almost all new electric
generation capacity has been gas-fired.  However, even if new coal-fired
baseload plants are constructed, due to changes in technology and to
additional regulatory requirements, their emissions of SO2 would be far
below the current average emissions rate for coal plants.  Coal plants
utilizing integrated gasification combined cycle, for example, would
emit little more SO2 than would natural gas-fired plants.  New
pulverized coal-fired plants would emit higher levels of SO2, but
probably at or below the average level of 1.4614 lbs/MWh used in the
calculation above.

The figure used in these calculations, 94.7 tons, is extremely
conservative.  Therefore, the best estimate of the net impact on SO2
emissions as a result of not shifting from wet scrubbers to baghouses,
taking into account increased emissions from power plants, is a net
decrease of 715 tons nationwide.

Establishing a MACT Floor for Existing Cupolas with Wet Scrubbers

In order to determine whether there is a solid case to be made for a
separate standard for all or some group of existing cupolas treated by
wet scrubbers (or, in the alternative, for a separate subcategory), a
comparison must be made between the SO2 increase that would be avoided
by creation of the separate subcategory and the decrease in PM that
would not be realized.  This evaluation requires first identifying the
appropriate PM emissions standard that would apply and thus estimate the
resulting emissions of PM.   

The starting point in this evaluation is to first determine what the
MACT Floor would be for existing cupolas equipped with wet scrubbers. 
According to a draft memorandum prepared by Jeff Coburn, RTI, for Kevin
Cavender, EPA, dated July 21, 2003, emissions information was available
for 71 cupolas controlled by venturi wet scrubbers.  In the Coburn
memorandum, Mr. Coburn takes 6% of 71, which is 4.3.  That memo states: 

[T]herefore, we evaluated the performance of the 4th and 5th best
performing units.  At the 99th percentile, these scrubbers achieved an
outlet PM concentration of 0.027 and 0.034 gr/dscf.  Consequently, it
appears that the MACT floor PM performance limit for cupola wet scrubber
systems is 0.03 gr/dscf.  

Coburn used the standard statistical technique EPA uses to move from an
average emissions concentration to a limitation reflecting a 99% degree
of confidence, but he also made a number of dubious assumptions. 

First, applying EPA’s typical approach to these facts, EPA would
generally look at the performance of the 5th best performing unit, since
that is the first unit that is performing at or below the 6% best
performance level.  The performance of the 4th best unit would not be
considered in setting the MACT floor since its performance is better
than the 94th percentile level.  The 5th best unit listed in EPA’s
database is Cupola D at the GM Saginaw facility.  The PM concentration
listed for this unit in that database is 0.021 gr/dscf.

Figure   SEQ Figure \* ARABIC  4 :  Ratio of Fine PM Decrease to Coarse
PM Increase

Second, Coburn apparently calculated the “relative standard
deviation” (RSD) by using all datapoints contained in EPA’s
spreadsheet “Cupola Test Data1.xls.”  This is a flawed approach.  A
better approach, would be to use only the data from wet scrubbers that
have average concentration levels of <0.03 gr/dscf so as not to mask the
variability that exists among the units that were used to establish the
MACT floor.  The low variability of units that emit at an average
emissions level too high to be considered in the development of the MACT
standard should not be used.  Moreover, the calculation of the average
RSD should be weighted to reflect the number of datapoints that exist
for a given unit.  A RSD for a unit with ten datapoints should be given
that proportionally more weight than the RSD for a unit with only two
datapoints.  Using this more sophisticated approach, the average RSD is
0.4927.

An even more sound approach would be to use the RSD derived from the ten
datapoints from Facility ID 407.  Ten datapoints from a single facility
are enough on which to base a reasonable estimate of variability, and
thus present a superior basis for estimating the expected variability of
wet scrubbers over time.  Using the data set with 10 data points rather
than 2 or 3 data points will lead to a more accurate assessment of the
variability of the emissions than using an average (or even a weighted
average) RSD.  

To the extent that emissions variability is due to variations in the
loading to the treatment system, such variability is far more likely to
be observed over time as the characteristics of the charge to the cupola
varies.  It is likely that the variability in the characteristics of the
charge to any given cupola will be small from run-to-run, but there is
likely to be significant variability month-to-month over the course of a
year.  The average emissions concentration for Facility ID 407 is
0.0162, and the RSD is 0.8342.

Applying the average of these two RSDs would result in the following:

(0.021 * 0.66345 * 2.326) + 0.021 = 0.0534

Rounding down to the nearest first significant figure, the resulting
value is 0.05.  The RSD for Facility ID 407 is significantly influenced
by one outlying datapoint.  If that datapoint were excluded, the RSD
would be 0.6707.  Averaging that RSD with the RSD for all facilities
with an average emissions value of <0.03 would result in the following
limitation:

(0.021 * 0.5817 * 2.326) + 0.021 = 0.0494

Again, rounding to the nearest first significant figure, the MACT Floor
for a subcategory of existing cupolas treated by wet scrubbers would be
0.05 gr/dscf.  

For the same reasons relied upon in the final rule by EPA to establish
an alternative metallic HAP standard that represents 8% of the total PM
standard, EPA should establish an alternative metallic HAP standard for
existing cupolas equipped with wet scrubbers that is 8% of the 0.05
gr/dscf total PM standard for the wet scrubber subcategory.  

If aggressive source separation or other means will allow a facility to
achieve the same low level of metallic HAPs as would result from
achieving the surrogate standard, that should be deemed compliance. 
That is the legal judgment embedded in the existing regulation, and that
same legal judgment should be applied to the separate standard we are
seeking for existing cupolas equipped with wet scrubbers.

To determine what the PM emissions would be from a subcategory
consisting of existing cupolas treated by wet scrubbers where the
emissions limitation is 0.05 gr/dscf, first the average emission of PM
from such a subcategory must be calculated.  This is different than what
the maximum theoretical emissions could be and it is different than what
existing cupolas treated by wet scrubbers might currently emit on
average.

The average PM emissions from such a subcategory would be approximately
0.021 gr/dscf, since this is the performance on which the standard of
0.05 would be based with an allowance for variability.  The wet scrubber
will have to operate at an average emissions level considerably below
the standard in order to avoid frequent and numerous violations of the
standard.  Similarly, units controlled by baghouses would have a far
better average emissions rate than the standard (0.006 gr/dscf)
contained in the rule.  Applying the same reduction factor to baghouse
emissions as we do in the case of wet scrubbers, we believe that
baghouse emissions would average approximately 0.00252 gr/dsf. 

These assumptions about performance echo the statement made by Kevin
Cavender of EPA in a memorandum to the docket, dated July 31, 2003: 
“The emissions from a baghouse will vary due to a number of
considerations.  Because the limit is never to be exceeded, we have
accounted for this variability in establishing the limit based on the
upper 99th percentile.  The upper 99th percentile is not intended to be
representative of the average performance of baghouses.  Moreover, the
data clearly shows that baghouses perform much better on average than
the standard.”  

It is clear that many of the existing wet scrubbers would have to be
substantially upgraded to achieve an average emissions rate of 0.021
gr/dscf, and this is entirely in keeping with the legislative intent
behind the MACT Floor.  Only by performing such upgrades will most of
the existing wet scrubbers be able to reliably and consistently achieve
a maximum emissions rate of 0.05 gr/dscf.  In addition, an important,
but unquantifiable benefit of the upgrades that will surely be necessary
for many existing wet scrubbers is enhanced SO2 removal.  The changes
that will be necessary to improve PM removal by the existing wet
scrubbers will result in enhanced removal of SO2 as well.  

The Resulting SO2 Increase Outweighs The Potential PM Decrease

If a separate source subcategory or standard is not established for
existing cupolas equipped with wet scrubbers, the result will be an
increase in SO2 emissions from cupolas replacing existing wet scrubbers
with baghouses.  Although the baghouses may result in some minor PM
reductions, those reductions will be outweighed by the increase in SO2 

The extraordinarily high rate of SO2 removal demonstrated in the recent
sampling performed at GM’s Defiance facility (over 97% removal) is an
illustration of the effect that wet scrubber upgrades have on both PM
removal and SO2 removal.  Engineering changes such as reducing down  the
recirculation of scrubber water substantially improved the ability of
the scrubber to reduce particulates and also substantially improved the
degree of SO2 removal. 

Using EPA’s data regarding PM emissions from each wet scrubber
equipped cupola, the emission rate can be adjusted downward in the
proportion necessary to reduce the concentration emitted so as not to
exceed the average of 0.0210 gr/dscf, e.g., the basis of the
contemplated standard of 0.05 gr/dscf, i.e., aa “MACT-compliant wet
scrubber”.  Similarly, PM emissions are adjusted to determine what the
emissions rate would be if the average concentration that would be
achieved by a MACT-compliant baghouse was reached.  As noted above, this
concentration rate is approximately 0.00252 gr/dscf.  

The PM reductions foregone by not replacing the wet scrubbers with
baghouses (that is, the PM increase) is then calculated by taking the
difference between the emissions rate for the cupola equipped with a
baghouse, and the emissions rate for the cupola with a MACT-compliant
wet scrubber.  This difference is then multiplied by the annual
production shown in Appendix   SEQ Appendix_ \* ALPHABETIC  A   of
EPA’s Background Information Document.   

As shown in   REF _Ref75130753 \h  Table 2 , imposing the Foundry Rule,
i.e., according to EPA, effectively mandating that wet scrubber systems
be removed and baghouse systems installed, the overall decrease in PM
emissions would only be 373.5 tons.  This is the total decrease in PM if
the MACT rule is implemented as currently drafted.  

Moreover, of those PM emissions, only a fraction of the emissions are
the metal HAPs which are supposed to be the subject of this rulemaking. 
Assuming that of the PM emissions from the cupola, only 5.9% is actually
metal HAP, with manganese being the primary metal HAP constituent (at
3.3% of the total PM).  In short, the amount of metallic HAP that would
pass through a MACT compliant wet scrubber but be caught in a fabric
filter is nominal.

Table   SEQ Table \* ARABIC  2 :  Increase in PM Per Emission Group

Group	PM Net Increase (tpy)

All Wet-Scrubbed Units	373.5

Units with Both SO2 and PM Data	186.8

Units with Both SO2 and PM Data and Production >125,000 tpy	151.0

Summary of SO2 and PM Calculations and Comparison with Lime
Manufacturing NESHAP

Finally, as illustrated in   REF _Ref75134606 \h  Table 3 , the increase
in emissions of SO2 is significantly greater than the reduction in PM. 
The ratio of the resulting increase in SO2 emissions is even more
striking when evaluating the result of replacing existing wet scrubbers
with baghouses on larger operations, i.e., the increase in SO2 is more
than 2 ½ times the decrease in PM.  The ratio of increases in SO2
emissions to decreases in PM emissions is even greater than the ratio
found in the Lime Manufacturing rule.   

Table   SEQ Table \* ARABIC  3 :  Changes in PM & SO2 Emissions
Resulting from NOT Replacing WS with BH

Group	Net ( SO2

(tons)	Net ( PM 

(tons)	Ratio

Lime Manufacturing 	-1830	+1080	1.69:1

All Wet-Scrubbed	-715.07	+373.5	1.91:1

Units with SO2 and PM Data	-384.86	+186.8	2.06:1

Units with SO2 and PM Data and >125,000 tpy Production	-386.33	+151.0
2.56:1

In the Lime Manufacturing NESHAP, EPA took the SO2 “disbenefit”
effectinto account and, instead of mandating removal of wet scrubber
systems, EPA determined that the increase in SO2 emissions would
outweigh the potential benefits from PM reductions.  Since EPA never
conducted this analysis prior to the proposal or promulgation of the
Foundry NESHAP, the trade-off of reducing a small amount of PM in
exchange for an increase of approximately twice as much SO2 was not
evaluated..  

Not only are SO2 emissions regulated as a criteria pollutant, it has
also been implicated as a precursor to the formation of fine
particulate.  Thus, just as EPA will be telling state air quality
agencies to identify and reduce emissions of fine particulate and
precursors to fine particulate for purposes of attainment and
maintenance of the new PM-2.5 standard, EPA will also be enforcing a
rule that is completely contradictory in that it will result in an
increase in emissions of precursors to PM-2.5.  This result is
illogical, i.e., an environmental regulation that effectively mandates
an increase in air emissions.  Particularly troubling is the fact that
EPA did not evaluate the overall impact of this SO2 “disbenefit”. 
The concern over the potential air quality impacts resulting from the
Foundry Rule should be enough to cause the Agency to reconsider the
final Foundry NESHAP.  

Creating a Separate Standard or Establishing a Separate Subcategory for
Existing Facilities Operating a Wet Scrubber-Equipped Cupola Would
Result in an Air Quality Bonus by Reducing  PM2.5 Emissions

Even more important than the decrease in SO2 emissions that would result
from subcategorizing wet scrubber equipped cupolas is that it would
prevent the formation of a considerable amount of fine particulate.  As
noted in the preamble to the final Lime Manufacturing NESHAP rule,
approximately 46% of the SO2 emitted into the atmosphere converts to
fine PM.  As shown in this section, the substantial decrease in
emissions of SO2 that would result from the grant of the relief we seek
would result in a substantial net decrease in the overall mass of fine
particulate compared to what would result from implementation of the
current rule.  

In the Lime Manufacturing NESHAP, EPA observes that “it is difficult
to make comparisons between the relative benefits of reducing emissions
of fine and coarse PM.”  Then, EPA states:  

The EPA views this situation as equivocal:  It is unclear which of these
types of performance is best since on the one hand there is reduced
emissions of HAP metals and coarse PM but foregone control of SO2 and
sulfate (fine) PM, and for kilns controlled with wet systems, the
converse.  In this situation, and based on these facts, which, with
current analytic tools seem to us to be largely in equipoise, we are not
prepared to view either wet or dry systems as best performing and
instead are promulgating a separate PM standard for each.  Id.   

The net reduction in fine PM resulting from promulgation of the separate
standard for existing lime kilns equipped with wet scrubbers was 1.41
times greater than the increase in coarse PM.  In the case of the Iron
and Steel Foundry NESHAP, the net reduction in fine PM that would result
from promulgation of separate standards for existing cupolas equipped
with wet scrubbers would be a significantly larger 2.28 times greater.

The detailed calculation of the effect of establishing a separate PM
standard for existing cupolas equipped with wet scrubbers builds on the
calculation of net PM effects, discussed earlier.  Reflecting the fact
that Table 12.10-9 of AP-42 indicates that 94.9% of particulate matter
emitted from a cupola controlled by a baghouse is 2.5 (m or smaller, the
adjusted emissions factor for each cupola calculated to show what would
be emitted after that cupola was retrofitted with a MACT-compliant
baghouse is multiplied by 0.949.  Similarly, the adjusted emissions
factor for each cupola calculated to show what would be emitted from
that cupola equipped with a MACT-compliant wet scrubber is multiplied by
0.777, since Table 12.10-9 of AP-42 indicates that 77.7% of particulate
matter emitted from a cupola controlled by a wet scrubber is 2.5 (m or
smaller.  The difference between these two fine PM emissions factors is
then multiplied by the annual production for each facility to derive the
increase in fine PM emissions as a result of not replacing wet scrubbers
with baghouses.  This increase is shown in Attachment   SEQ Attachment
\* ARABIC  1 .

However because nearly half of the SO2 emitted has the potential to form
fine particulate, and since that fine particulate oxidized in the
atmosphere to SO42+ (which has a molecular weight of 96 compared to 64
for SO2), the mass of fine particulate attributable to SO2 emissions
equals 69% of the mass of the total SO2 emitted.   EPA observes that
“it is difficult to make comparisons between the relative benefits of
reducing emissions because cupola emissions contain a substantial
quantity of SO2, the SO2 reductions that would result from the changing
the rule to explicitly accommodate wet scrubbers would more than offset
the increase in fine PM emissions directly from the cupolas.  A summary
of these calculations is presented in   REF _Ref75137312 \h  Table 4 .  

Table   SEQ Table \* ARABIC  4 :  Summary of Net Changes In PM

Facilities	Increase in Emissions of Coarse PM

	Net Decrease in Emissions of Fine PM

	Net Decrease in Emissions of Fine PM*

	Ratios

Adj Fine PM Decrease to Coarse PM Increase

All Facilities	93.801	278.996	213.653	2.28

With Both SO2 and PM Data	46.657	160.846	125.357	2.69

Both Data and >125,000 tpy	37.726	183.272	153.317	4.06

Lime Manufacturing Plants	450	632.700	632.700	1.41

* Adjusted for emissions due to electric generation.

EPA Should Either Create Separate Standards or Create a Separate
Subcategory for Cupolas Equipped with Wet Scrubbers in order to Account
for the Superior SO2 and Fine Particulate Performance of Wet-Scrubbers

The substantial increase in sulfur dioxide emissions and fine
particulates that would accompany a conversion of existing wet scrubbers
to baghouses is a compelling reason for the Administrator to exercise
his discretion to create a separate standard or a subcategory.   The
statutory terms “classes” and “types” are sufficiently broad and
general to encompass distinctions of any nature, including distinctions
based on the type of treatment system employed.  While generally it
would be inappropriate to create a subcategory to reflect the lesser
performance of one treatment technology compared to another, the
subcategory we are seeking here as an alternative remedy is intended to
reflect and preserve the superior performance of a treatment technology
in removing an important pollutant – SO2 – and to ensure that the
regulation does not lead to an increase in fine particulates.  Because
this superior performance implicates the fundamental mission of the
Agency to protect human health and the environment, it is certainly
appropriate for the Administrator to take this superior performance in
SO2 removal and fine particulate control into account in exercising his
substantial discretion to create subcategories.  

Further, the MACT floor for existing facilities is to be based on the
“best performing” existing sources.  Given the superior performance
of wet scrubbers in terms of SO2 removal and in the minimization of fine
particulates, and the superior performance of baghouses in terms of
particulate removal, it is not at all clear what the “best
performing” sources are.  This is particularly true when we consider
the effect on the level of fine particulates.  Here, the continued use
of wet scrubbers would result in a greater decrease in the mass of fine
particulates than the increase in the mass of coarse particulates that
would also result.  

We do not contend that wet scrubbers are better performing than
baghouses; but at the same time we do not believe that EPA is compelled
to conclude that baghouses are better performing than wet scrubbers. 
There simply is not a single and consistent scale for determining which
type of performance is “better.”  It is possible to determine which
“apples” are better than other “apples,” and it is possible to
determine which “oranges” are better than other “oranges,” but
it is not possible to determine whether “apples” are better than
“oranges.”  Only by putting wet scrubber-controlled cupolas and
baghouse-controlled cupolas into separate subcategories or other
separate groupings is it really possible to tell which units are the
better performing.

This same point was made by EPA in the NESHAP for Lime Manufacturing
Plants published in Federal Register on January 5, 2004.  There, EPA
adopted a separate standard for existing lime kilns that have installed
and are operating wet scrubbers prior to January 5, 2004.  That separate
standard for particulate matter was substantially above the PM standard
for other lime kilns, which was based on the performance of kilns
controlled by baghouses.  See 69 Fed.Reg. at 402-405 (Jan 5, 2004).  

‘The EPA views this situation as equivocal:  It is unclear which of
these types of performance is best since on the one hand there is
reduced emissions of HAP metals and coarse PM but foregone control of
SO2 and sulfate (fine) PM, and, for kilns controlled with wet systems,
the converse.  In this situation, and based on these facts, which, with
current analytic tools seem to us to be largely in equipoise, we are not
prepared to view either wet or dry systems as best performing and
instead are promulgating a separate PM standard for each.’  69 Fed.
Reg. at 404.

EPA thus deals with the requirement that the MACT floor be based on the
“best performing” sources within a category or subcategory by
concluding that it is impossible to say whether wet scrubbers or
baghouses are the “best performing.”  EPA did not create a separate
subcategory, but instead it calculated two distinct MACT floors – one
for lime kilns equipped with wet scrubbers as of the date of
promulgation, and one for all other lime kilns.  

While we believe that EPA has adequate discretion to create a separate
subcategory for existing iron and steel foundry cupolas equipped with
wet scrubbers based on the superior performance of wet scrubber-equipped
cupolas in removing SO2 and in reducing the mass of fine particulate
matter that results from operation of cupolas, we believe that doing
what the Agency did in the Lime Manufacturing NESHAP is perfectly
appropriate as well.  The creation of a distinct standard for different
facilities within the same subcategory is consistent with the explicit
language of § 112(d)(1) which states “[t]he Administrator may
distinguish among classes, types, and sizes of sources within a category
or subcategory in establishing such standards ....” (emphasis added). 

In addition, it is perfectly consistent with the requirement for a MACT
floor in § 112(d)(3) that is no less stringent than “the average
emission limitation achieved by the best performing 12 percent of the
existing sources ....”  Where, as in the case of the Lime
Manufacturing NESHAP and as is currently the case with the Foundry
NESHAP, there are two distinct sets of what constitutes the “best”
within a single subcategory, there must be two distinct standards
reflecting those distinct sets of best performances.

Cupolas with Wet Scrubbers Are Not Similar Sources To Cupolas with
Baghouses & Should Be Regulated Under a Separate [Sub]Category or
Standard

Wet Scrubber Systems Are An Integral Part of the Process 

As acknowledged by EPA, unlike a baghouse, a “wet scrubber is an
integral part of the cupola.”  Unlike some control technologies, a
wet-scrubber is not merely an “off the shelf” and fungible add-on
control technology.  In fact, as shown in   REF _Ref75299664 \h  Figure
5 , it is apparent that the wet scrubber is not only integral, but in
fact, it also makes up a major portion of the melting operation itself. 

Conversely, baghouses are not generally viewed as “integral” to the
cupola.  Although they have to be sized properly to handle the air flow
(including the volume of air handled, the temperature of the exhaust
stream, etc.), the baghouse itself is an add-on control.  Thus, removing
or replacing a baghouse on a cupola, though difficult and expensive,
does not generally require making the type of major process changes that
would be required to remove or replace a wet scrubber system.  

Unlike baghouse technology, the wet scrubber systems that have been
constructed to treat the emissions from cupolas are so large and
substantial in comparison with the cupola itself, it is appropriate to
consider cupolas equipped with wet scrubbers to be in a distinct
“class” or to be of a different “type” from cupolas not equipped
with wet scrubbers.  Again, as shown in   REF _Ref75299664 \h  Figure 5
, the cupola is only a small portion of the process.  Thus, under the
current rule, cupolas equipped with wet scrubbers will have to be
virtually reconstructed in order to remove the wet scrubber system and
to install a baghouse.  In fact, rather the cupola being virtually
reconstructed, it would be more accurate to state that the entire
process will have to be reconstructed.  In fact, it would be less costly
to replace the entire system, cupola and all, rather than try to
retrofit a baghouse.  

As described above, the EPA has broad discretion to establish source
categories and subcategories that will best facilitate the purpose and
intent of the CAA.  The most direct statutory guidance on
subcategorization appears in §112(c)(1):

To the extent practicable, the categories and subcategories listed under
this subsection shall be consistent with the list of source categories
established pursuant to section 7411 of this title and part C of this
subchapter.  Nothing in the preceding sentence limits the
Administrator’s authority to establish subcategories under this
section, as appropriate.

The second sentence is a blanket grant of authority to the Administrator
“to establish subcategories under this section, as appropriate.” 
The determination of whether a subcategory is “appropriate” is a
matter of judgment left to the discretion of the Administrator.  To the
extent that the reference to §111 in the first sentence above is not
rendered totally irrelevant by the second sentence,  §111 still has
very little significance here because iron and steel foundries are not
regulated under §111.  

Nonetheless, it is worth noting that §111(b)(2) provides the
Administrator with discretion to “distinguish among classes, types and
sizes within categories of new sources for the purpose of establishing
such standards.”  Similar language is contained in §112(d)(1):  
“The Administrator may distinguish among classes, types, and sizes of
sources within a category or subcategory in establishing such standards
except that, there shall be no delay in the compliance date ....”  As
the D.C. Circuit recently observed in a case involving a similar
statutory provision under the Clean Air Act also authorizing EPA to
“distinguish among classes”

The word “Class” is an ambiguous term.  It is not defined in the
Clean Air Act, and the dictionary definition – “a group, set, or
kind marked by common attributes”  -- could hardly be more flexible.  
... There is certainly nothing about the term or its dictionary
definition that precludes the use of aggregate plant capacity as a
factor for drawing distinctions among units.

Likewise, there is certainly nothing about the term “class” to
preclude EPA from including treatment systems intertwined with the
production process in determining whether the overall process is within
the same “class.”  Typically, the treatment system will be but a
relatively small part of the overall process, and so differences in
treatment systems will not be enough to put otherwise similar facilities
into a different class.  But where, as here, the treatment system is an
integral and very substantial part of the overall process, EPA has the
discretion to recognize the differences and to establish appropriate
classes.

Section 112 was never intended to require the replacement of facilities,
only the upgrading of pollution controls.  In the unique circumstances
of the Iron and Steel Foundry NESHAP, the change from wet scrubbers to
baghouses is tantamount to replacement of the entire cupola.

Large or Multiple Cupola Facilities with Wet Scrubber Operations Are
Unique and Should Be Regulated Under a Separate [Sub]Category or
Standard

The large capacity foundries with multiple cupolas have numerous
features distinguishing them from other foundries.  For example, looking
at the list of foundries that operate cupolas with wet scrubber systems,
the three largest “affected sources” are twice the size of the next
largest foundry.  In addition to having the most capacity and production
throughput, these top three facilities share unique problems that would
not likely be of the same magnitude or difficulty for smaller
operations.  

For example, the Ford Cleveland Casting facility is the second largest
foundry operation with four large capacity existing wet scrubber
controlled cupolas.  The facility operates four large capacity cupolas
with melting capacities ranging from 47 tons per hour up to 70 tons per
hour.  Assuming flow rates for each exhaust stream of 60,000 cfm to
70,000 cfm, with an air to fabric ratio of 1.5:1, the surface area of a
baghouse would have to be between 40,000 and 47,000 square feet.  

Thus, as large as the wet-scrubber system is compared to the cupola
itself, the area required to install a baghouse for the same operation
would be approximately 4 times as large as what is required for the wet
scrubber.  This presents a significant problem for this facility because
the cupolas are located in the center of the building where space for
baghouses is limited.  Because of space constraints, installation of
these large baghouses would require a significant investment to
reconfigure the operations in that part of the building.  



Figure   SEQ Figure \* ARABIC  5 :  Diagram of Cupola & Wet Scrubber
System

The Emission Characteristics from a Wet Scrubber Contain Significantly
Less Acid Gas than Emissions from a Baghouse

As evident from   REF _Ref75338106 \h  Table 5  and   REF _Ref75338556
\h  Table 6 , wet scrubbers are far superior to baghouses for
controlling emissions of SO2.  For baghouses, the average pounds of SO2
emitted per ton of throughput is 0.155.  The median value is 0.115.  For
wet scrubber operations however, the emission factor drops to an average
of 0.021 lbs SO2/ton with a median value of 0.010 lbs SO2/ton.  Using
the average lbs SO2/ton, this represents a difference of over 86% (and a
difference in the median values of over 91%.)  Thus, removing wet
scrubbers from existing cupolas will result in an increase in SO2
emissions from those operations.  

Table   SEQ Table \* ARABIC  5 :  Summary of SO2 Data for Cupolas
Equipped with Baghouses

Plant - cupolas with baghouses	SO2 (lb/ton)

US Pipe (NJ-03) 1991 - [II-D-58]	0.059

US Pipe (NJ-03) 1997 [II-D-58]	0.072

Waupaca Tell City (IN-34) 1997 [II-D-41]	0.11

Waupaca Plant 1 (WI-01)1998 [G. Mosher e-mail]	0.115

Grede Reedsburg (WI-35) 1998 [II-D-117]	0.18

Charlotte Pipe (NC-05) 2000 [II-I-70]	0.23

Grede Reedsburg (WI-35) 2000 [II-I-73]	0.32

Average	0.155

Median	0.115

Replacement of a Wet Scrubber With a Baghouse Involves Extensive
Redesign and Re-engineering of the Process

As illustrated by   REF _Ref75299664 \h  Figure 5 , the wet scrubber
portion of the operation is not merely an add-on control unit.  The wet
scrubber is indeed an integral part of the process.  

Although a baghouse may not be nearly as integrated into the melting
process as a wet scrubber, installation of a baghouse does involve
extensive engineering, particularly to retrofit a cupola.  Switching to
a baghouse technology does not mean simply installing a baghouse.  As
described by the American Foundry Society (“AFS”) in comments
submitted on the draft Foundry NESHAP, installation of a baghouse also
requires installation and/or modification of other systems in the
process and in the facility to so as to accommodate the baghouse.  More
specifically, AFS stated:

. . . baghouses designed for cupolas require the addition of special
features such as hopper heaters, insulation and cladding, reagent
injection systems, special hopper designs, special auger designs and
dust conditioning systems, which the agency did not consider. These
design parameters have been proven necessary by experience, at cupolas
subject to stack testing, since cupola PM emissions are finer and, thus,
more difficult to collect than most other PM. As a result, these design
requirements increase the engineering, equipment, installation, and
operating costs of the control system and raise the overall cost
projection.

Table   SEQ Table \* ARABIC  6 :  Summary of SO2 Data for Cupolas
Equipped with Wet Scrubbers

Plant - cupolas with wet scrubbers	SO2 (lb/ton)

Atlantic States (NJ-04) [II-D-59]	0.0006

CMI Cast Parts (MI-13) 1997 [II-D-49]	<0.0015

Briggs & Stratton (WI-24) [II-D-80]	0.0015

Griffin Pipe (NJ-05) 1997 [II-D-60]	0.002

Waupaca  Plant 2/3 (WI-42) 1995 [II-D-83]	0.0023

Waupaca Plant 1 (WI-01) 1998 [G. Mosher e-mail]	0.006

 Waupaca Plant 2/3 (WI-42) 1997 [II-D-83]	0.0097

Great Lakes Casting (MI-17) 1996 [II-D-50]	<0.011

Waupaca  Plant 2/3 (WI-42) 1994 [II-D-83]	0.011

Charlotte Pipe (NC-05) 1994 [II-D-61]	0.015

Waupaca (WI-01) 1994 [II-D-78]	<0.02

LaGrange Foundry (MO-05) 1993 [II-D-100]	0.026

Wrightsville (PA-34) 1995 [Survey response for No.  688]	0.061

GM Saginaw (MI-33) 1995 [II-D-54]	0.12

Average	0.021

Median	0.010



Calculation of An Emission Limitation for the Wet Scrubber Category &
Subcategory

Emission Limitation for the Category of Existing Cupolas with Wet
Scrubbers

As described in Section V.A.3 of this Petition, the emission limitation
for existing cupolas with wet scrubbers should be set at 0.05 gr/dscf
for total PM, or, in the alternative, at the choice of the owner or
operator, at an equivalent limit of total metallic HAP emissions of
0.004 grains/dscf from the cupola emission stacks.

Emission Limitation for the Subcategory of Existing Multiple, Large
Co-located Cupolas with Wet Scrubbers

To determine the appropriate emission limitation for the subcategory of
existing multiple, large, co-located cupolas equipped with wet
scrubbers, available stack test data from EPA was analyzed.  Again, as
stated by EPA in a recent final NESHAP, EPA has the discretion to
“define a subcategory of facilities within the source category based
upon technological differences, such as differences in production rate,
emission vent flow rates, overall facility size, emissions
characteristics, processes, or air pollution control device
viability.”  Looking at the subcategory of affected sources with
multiple cupolas equipped with wet scrubbers, 

  REF _Ref75343394 \h  Table 7  lists the existing foundry operations
with multiple cupolas equipped with wet scrubbers.    REF _Ref75344239
\h  Figure 6  illustrates that there are further natural break points
between foundry operations (with multiple cupolas equipped with wet
scrubbers) based on the size of the “affected source”.  Based on
total annual iron production capacity of the affected source, there
appear to be 3 major discrete groupings – small, medium, and large.  



Table   SEQ Table \* ARABIC  7 :  Existing Operations with Multiple
Cupolas Equipped with Wet Scrubbers

#	Facility Name	Total Number of Cupolas	Total Iron Annual Production
Capacity (TPY)

1	GM Defiance	4	1,368,167 

2	Ford Cleveland	4	526,000 

3	GM Saginaw	3	448,682 

4	Gunite Corporation	2	224,250 

5	Tyler Pipe Company	2	219,308 

6	Wheeland Foundry #2	2	200,000 

7	U.S. Pipe, N. Birmingham	2	189,287 

8	U.S. Pipe	2	183,957 

9	Wheeland Foundry #1	2	164,820 

10	Intermet Lynchburg	2	148,213 

11	Neenah Plant 2	2	137,586 

12	Osco Industries, Inc	2	74,555 

13	New Haven Foundry	2	57,190 

14	CWC, Textron	2	52,704 

15	Grede Foundries, Inc. Perm Cast	2	44,681 

16	Stockham Valves and Fittings 	3	35,993 

17	Eljer Industries	2	31,181 

18	U.S. Castings/U.S. Pipe	2	19,837 

19	Gardner Denver Industrial Mach	2	19,243 

20	Vulcan Foundry	2	18,580 

21	Jahn Foundry Corp.	2	12,300 

22	Opelka Foundry Co. 	2	8,225 

23	Hempfield Foundry	2	2,289 

24	Sidney Division	2	1,088 

Starting on the left hand side of the chart, the first natural break
appears between “affected sources” # 3 (the GM Saginaw facility) and
#4 (the Gunite Corporation facility).  This natural break occurs at a
point where the larger facility has a total iron production capacity of
approximately two times the next nearest facility.  Thus, the “large
source subcategory” for “affected sources” with multiple cupolas
equipped with wet scrubbers would consist of the 3 largest sources,
i.e., GM Defiance, Ford Cleveland, and GM Saginaw.  The next natural
break occurs between the Neenah Plant #2 and the Osco Industries
operations.  Again, the larger facility in this grouping is nearly twice
the size of the next nearest competitor.  Hence, the medium size
category would consist of the Gunite Corporation, Tyler Pipe, Wheeland
#1 and #2, U.S. Pipe, Intermet Lynchburg, and Neenah #2.  The remainder
of facilities would fall under the small source category.  

Figure   SEQ Figure \* ARABIC  6 :	Illustration of Natural Break Points
in Wet Scrubber Category Based on Size

According to the CAA, for source categories with less than 30 sources,
the emission standard is the average emission limitation achieved by the
sources.  Available test data from the large source category facilities
is shown in   REF _Ref75573759 \h  Table 8 .  It is important to note
that stack test data represents merely a “snapshot” of the emissions
from a given operation at the time the “snapshot”, i.e., test was
conducted.  

As would be expected from such a large manufacturing operation, there is
considerable variability in stack test results from test run to test
run.  That does not mean that the results are inaccurate, instead it is
most likely reflective of the true variability of emissions from such
operations.  

The variation in test runs is well illustrated by   REF _Ref75579776 \h 
The standard deviation (“SD”) is a slightly more sophisticated
statistical means of evaluating the amount that the individual data
points differ from the mean of all the data points, i.e., it is a means
of evaluating how meaningful the average is for the data set.  For
smaller data sets, a relative standard deviation may be used.  The
relative standard deviation (“RSD”) is the standard deviation
divided by the mean of the data set and is represented as a percentage. 
These statistical values are shown in Table 9.

Although the variation in values is apparent from Figure 7, the
statistical information Table 9 illustrates the magnitude of the
variation.  For example, for cupolas with more than 1 test run, the RSD
ranges from 4% up to 73%.  Interestingly, the 73% RSD is based on the
most test run values, i.e., has the most data upon which to base a RSD. 
This could be viewed as implying that greater the number of tests
conducted, the more explicit the variation between test runs, i.e., the
more proof that there is considerable variation in emissions from a
single cupola during normal operation.  

Figure 7  Although each test run was conducted in accordance with
EPA’s reference test method, and even though many of the tests were
conducted on the same day, there is still considerable variation in the
results.  

To quantify this variation, the minimum, maximum, average, median and
standard deviation for each set of tests for each cupola was evaluated. 
Also, since there are not many data points, the relative standard
deviation was also calculated.  Each of these statistical values helps
to provide a more quantitative assessment of degree to which data within
a data set vary.  For example, the minimum value and the maximum value
illustrate the range of the data in the sample.  The average provides
the mean value of the data in the sample whereas the median represents
the central value in the data set.  Very simplistically, when the
average and the median are very close in value, then the data is
relatively evenly distributed around the mean.  If the average and
median are not close in value, that is generally indicative that the
data set has a wide range of variability.  

Table   SEQ Table \* ARABIC  8 :  Test Data for the Large Source
Category of Existing Cupolas with Wet Scrubbers

Plant	Cupola	Date	Test Runs (PM in gr/dscf)

	1	2	3	4	5	6	7	8

GM Powertrain Saginaw	B	9/97	0.0073	0.015	0.016	0.0035	0.0035	 	 	 

	C

0.0419	 	 	 	 	 	 	 

Ford Cleveland Casting	7	12/17/1997	0.0261	0.0218	0.0214	 	 	 	 	 

	1	11/11/1997	0.0544	0.0475	0.0488	 	 	 	 	 

	3	11/12/1997	0.0551	0.0544	0.0509	 	 	 	 	 

	2	11/18/1997	0.0710	0.0655	0.0605	 	 	 	 	 

GM Defiance	3	12/98	0.0112	0.039	0.068	0.03	0.117	0.034	0.022	0.045

	6E	8/12/1998	0.0280	0.055	0.051	 	 	 	 	 

	6W	1/11/1996	0.031	0.027	0.027	 	 	 	 	 

	6W	2/11/1998	0.0490	0.033	0.025	 	 	 	 	 

	4(dwell)*	10/14/1997	0.029	0.039	0.027	 	 	 	 	 

* Cupola #4 has two exhaust streams – recoup and dwell.  Thus
#4(calculated) represents the calculated value of PM based on tests of
the recoup and dwell exhaust.  

The standard deviation (“SD”) is a slightly more sophisticated
statistical means of evaluating the amount that the individual data
points differ from the mean of all the data points, i.e., it is a means
of evaluating how meaningful the average is for the data set.  For
smaller data sets, a relative standard deviation may be used.  The
relative standard deviation (“RSD”) is the standard deviation
divided by the mean of the data set and is represented as a percentage. 
These statistical values are shown in   REF _Ref75575821 \h  Table 9 .

Although the variation in values is apparent from   REF _Ref75614140 \h 
Figure 7 , the statistical information   REF _Ref75575821 \h  Table 9 
illustrates the magnitude of the variation.  For example, for cupolas
with more than 1 test run, the RSD ranges from 4% up to 73%. 
Interestingly, the 73% RSD is based on the most test run values, i.e.,
has the most data upon which to base a RSD.  This could be viewed as
implying that greater the number of tests conducted, the more explicit
the variation between test runs, i.e., the more proof that there is
considerable variation in emissions from a single cupola during normal
operation.  

Figure   SEQ Figure \* ARABIC  7 :  Graph of Stack Test Runs from 3
Largest Sources

The CAA provides that the NESHAP for an existing source in a source
category with less than 30 sources is to be based on “the average
emission limitation achieved by the best performing 5 sources . . . in
the category or subcategory.”  When an emission standard under the CAA
uses the term “achieved”, the courts have consistently held that the
emission standard must be based on what can be achieved under the
“worst foreseeable circumstances”.  National Lime Ass’n v. EPA,
233 F.3d. 625 at 631 (D.C. Cir. 2000).  More specifically, the court
stated:

EPA's technology-based approach to setting new source emission standards
has already faced and survived a Chevron one challenge.  In Sierra, 167
F.3d 658, we reviewed a new source emission standard for solid waste
combustion that EPA promulgated pursuant to section 7429, which
establishes emission requirements virtually identical to section 7412's.
 There, as here, the Sierra Club argued that EPA's MACT technology
approach to setting emission standards is unambiguously forbidden by the
Clean Air Act.  Sierra rejected that argument, holding that EPA may
estimate the performance of the best performing units and that it was
not ``impossible'' that EPA's methodology constituted a reasonable
estimation technique.  See 167 F.3d at 665.  Concluding that EPA could
reasonably interpret the statutory phrase ``emissions control that is
achieved in practice'' to mean emissions control that is ``achieved
under the worst foreseeable circumstances,'' see id. (citing National
Lime Ass'n v. EPA, 627 F.2d 416, 431 n. 46 (D.C.Cir.1980)), we
hypothesized: ``perhaps considering all units with the same technology
is justifiable because the best way to predict the worst reasonably
foreseeable performance of the best unit with the available data is to
look at other units' performance.''  Id. at 665.  (emphasis added.)

Table   SEQ Table \* ARABIC  9 :  Statistical Evaluation of the Stack
Test Runs

(Max-Min)	78%	0%	18%	13%	8%	15%	90%	49%	13%	49%	33%

Since there are only three sources in the existing source large wet
scrubber category, these operations are by definition the best
performing sources.  Since all three are large, multi-cupola operations
with wet scrubbers for PM control, they are also similar sources.  Thus
the MACT for this subcategory must be based on the “average emission
limitation achieved”.  

In order to assure that the MACT is set at a level that is achievable,
the emission limit must take the wide variability of the normal
operating ranges of these operations into account as reflected by the
test results.  Taking the arithmetic mean of the all of the test results
from each cupola would result in an emission limit of 0.0388 gr PM/dscf.
 That emission limit however would mean that only 18 of the 35 stack
test runs would demonstrate compliance.  The result is similar if the
average of the average aggregate cupola emissions are evaluated.  For
that scenario, the limit would be 0.0398 gr PM/dscf.  Again, using this
methodology, only 18 of the 35 stack test results would be under the
limit.  In short, this could lead to almost half of the operations being
out of compliance in any given hour.  Although for purposes of
compliance testing, 3 1-hr tests could be averaged, it is clear based on
the variability of the test runs that even averaging emissions over 3
hours would likely not greatly increase the likelihood that an operation
would meet such a standard.  

Instead, given the variability of the stack test results, and the basic
principle that the standard must be achievable, even during the worst
period of performance for the best source(s), then the maximum test
results from these best performing sources should be used.  More
specifically, taking the average of the best performing sources in the
large existing wet-scrubber equipped cupola operation, the standard
would become 0.0516 gr/dscf.  Even at this emission level, nearly 29% of
the emissions determined in the test runs would exceed the limit.  Those
that met the limit would not necessarily do so with enough confidence
that 100% compliance could be assured without engineering some
improvements to the system.  

As one of the commenter’s on the proposed rule stated, a high-energy
wet scrubber has a PM removal efficiency of approximately 97.8% where as
a fabric filter would have an approximate efficiency of 99.8%.  That
represents only a 2% difference in PM removal efficiency.  

Conclusion

Implementation of the Foundry rule as currently drafted will result in
an overall adverse environmental impact.  By effectively requiring
existing cupolas equipped with wet scrubbers to remove those scrubbers
and retro-fit baghouses to the operation.  The result of this change in
control technology is the loss of the side benefit to the wet scrubber
system, i.e., the capture of acid gases such as SO2.  Baghouses will not
capture SO2, and so the end result will be an overall projected increase
in SO2 emissions of over 700 tons per year.  In addition to the direct
increase in SO2, there will also be a cascading effect to this rule,
i.e., since SO2 is a precursor to the formation of PM-2.5, this increase
in SO2 will also trigger an increase in fine particulate.  On the other
hand, the only air quality benefit of this rule will be a nominal
decrease in emissions of PM.  Clearly the impact of the increase in SO2
outweighs the decrease in PM.  

As written, the rule regulates all cupolas under one regulatory
umbrella.  This is inappropriate since there are numerous distinctions
between cupolas equipped with wet scrubbers and cupolas which exhaust
through baghouses.  These differences range from the fundamentals of the
way the process itself operates, to the differences in the quantity and
nature of air pollutants emitted.  In short, the only similarity between
cupolas equipped with wet scrubbers and cupolas equipped with baghouses
is that they are both capable of melting iron.  That is not enough to
consider the sources “similar” under the CAA.  

Moreover, although EPA has declared that costs will not be considered in
setting NESHAP standards, except for purposes of determining whether to
go “above the floor”, i.e., establish an even more stringent
standard.  However, regulating cupolas with wet scrubbers in exactly the
same way as cupolas equipped with baghouses is effectively an “above
the floor” mandate since the two operations are substantially
dissimilar and the MACT floor for these operations should not have been
established as though they would be the same.  

However, even as an above the floor standard, the emission limitation
imposed on existing cupolas equipped with wet scrubbers is far too
costly to be supported by the intent of the statute.  It is particularly
damaging that the harshest and most costly impacts of this rule will
fall on just a few.  Specifically, EPA recognized in the Economic Impact
Analysis of this rule that the vast majority of the cost of this rule
would fall on a minority of the sources:

The rule requires some iron and steel foundries to implement pollution
control methods that will increase the costs of producing iron and steel
foundries at affected facilities.  The increased production costs
primarily affect iron foundries . . . .  The impacts of these price
increases will be borne largely by affected iron foundries that use
cupola furnaces as well as consumers of iron foundry products. 
(emphasis added.)

For these reasons, the Alliance respectfully requests that the
Administrator convene a proceeding to reconsider the final NESHAP for
iron and steel foundries so as to amend rule to assure that it is
consistent with the purpose and intent of the CAA by protecting public
health and welfare while promoting the productive capacity of the United
States.  Developing two standards for existing cupola operations – one
for those equipped with wet scrubbers and a separate standard for those
equipped with baghouses will result in an overall environmental benefit
by resulting in an overall reduction in particulate matter but without
sacrificing the benefits of SO2 reduction achieved by wet scrubber
systems.  

Respectfully Submitted

WARNER NORCROSS & JUDD LLP

Rhonda L. Ross

2000 Town Center, Suite 2700

Southfield, MI 48075

(248)784-5000

rross@wnj.com

June 21, 2004

Alliance of Automobile Manufacturers Comments on the Proposed Rules for
National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries (67 Fed. Reg. 78274, December 23, 2002), dated February
21, 2003.  (Docket ID:  OAR-2002-0034-0044)

 NESHAP for Iron and Steel Foundries, Background Information for
Proposed Standards, EPA 453/R-02-013, page 5-11, December 2002.  

 Although existing wet-scrubbers were most likely initially installed to
control PM, they have a side benefit of also controlling emissions of
acid gases such as oxides of sulfur and oxides of nitrogen.  Not only
are Sulfur Dioxide and Nitrogen Dioxide regulated as criteria
pollutants, but they are now widely viewed by EPA as being precursors to
fine particulate (i.e., particulate matter with an aerodynamic diameter
of 2.5 microns or less (“PM-2.5”).  

 In addition to controlling emissions of SO2 better than fabric filters,
there is also some indication that wet scrubbers may also reduce
emissions of mercury as well.  

 40 CFR Part 63, Subpart EEEEE.

 Since EPA has asserted that the Agency has broad authority to establish
categories and subcategories under the NESHAPs, The term
“subcategory” shall be used from this point forward shall mean
either category or subcategory.

  42 U.S.C. § 7412.

 42 U.S.C. §7607(d)(7)(B).

 National Emission Standard for Hazardous Air Pollutants for Lime
Manufacturing Plants; Final Rule, 69 Fed. Reg. 394, January 5, 2004. 
See also, 40 C.F.R. Part 63, Subpart AAAAA.

 Although the NESHAP for Lime Manufacturing Plants was signed on August
25, 2003, a little less than 5 months prior to publication in the
federal register, the signing still took place almost 6 months after the
close of the comment period on the Foundry Rule and thus could not be
reviewed for applicable precedent in advance of submitting comments.  

 In addition, this petition is also based on an analysis of information
regarding the engineering/technical distinctions between existing
cupolas equipped with wet-scrubbers and cupolas with baghouses. 
Wet-scrubber systems are not a fungible piece of equipment that can
simply be removed and replaced with a baghouse.  Instead, the
wet-scrubber systems associated with cupolas are an integral part of the
melting operation itself.  Changing from a wet-scrubber to a baghouse is
not merely an exercise in retrofitting the equipment.  Instead, each
system would need to have engineer “designer baghouses” specific to
the size, capacity, flow rates, and other parameters related to the flow
of the manufacturing line from start to finish.  

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78276, December
23, 2002.  

 Diagram from Economic Impact Analysis of Proposed Iron and Steel
Foundry NESHAP, Final Report, November 2002, EPA 452/R-02-01, p. 1-2.  

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78276, December
23, 2002.  

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78276, December
23, 2002.  

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78277, December
23, 2002.  

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Background Information Document for the Proposed Rule,
EPA-453/R-02-013, December 2002.

 For the organic HAP, most cupolas have afterburners installed which,
according to EPA, “effectively destroy organic HAP”.  See, National
Emission Standards for Hazardous Air Pollutants for Iron and Steel
Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78278, December 23,
2002.  Thus, the organic HAP emissions are not an issue in this Petition
for Reconsideration.  

 “Energy and Environmental Profile of the U.S. Metalcasting
Industry”, Prepared for the U.S. Department of Energy, Office of
Industrial Technologies, September 1999, p. 29. 
http://www.oit.doe.gov/metalcast/pdfs/profile.pdf. 

 According to the BID for the proposed rule, there are 143 cupolas for
in 110 iron foundries.  A little less than half of those cupolas are
controlled by wet scrubber systems (71 furnaces) and fabric filters
(also known as baghouses) are used on 62 of the furnaces.  See, National
Emission Standards for Hazardous Air Pollutants for Secondary Aluminum;
Proposed Rule; 64 Fed. Reg. 6945 at 6959, February 11, 1999.

 Clean Air Act, 42 USC §7401 et. seq.

 National Emission Standards for Hazardous Air Pollutants for Secondary
Aluminum; Proposed Rule; 64 Fed. Reg. 6945 at 6959, February 11, 1999

 NESHAP for Plywood and Composite Wood Products,
www.epa.gov/ttn/oarpg/t3/fr_notices/pcwp_fr.pdf.

 National Emission Standard for Hazardous Air Pollutants for Hazardous
Waste Combustors, Proposed Rule, 69 Fed. Reg. 21198   at 21213, April
20, 2004.

 40 C.F.R. § 63.7690(a)(2).

 Comments of the American Foundry Society on the proposed NESHAP for
Iron and Steel Foundries, February 21, 2004.

 From Table 5-11 of the Background Information Document for the Proposed
Iron and Steel Foundry NESHAP.

 The estimate of SO2 emissions is particularly conservative because it
presumes that all of the energy differential between wet scrubbers and
baghouses would be generated by coal fired electrical generating units. 

 In addition, if,  a separate standard for existing cupolas equipped
with wet scrubbers is limited to those facilities with annual production
greater than 125,000 tons per year, the ratio of SO2 reductions to PM
increase is greater than 2.5:1 – still well above the ratio in the
Lime Manufacturing NESHAP where EPA found justification for a separate
standard.  

 See EPA, Final Report – Volume I of II, Iron and Steel Foundries
Manual Emissions Testing, Cupola Wet Scrubber, General Motors Corp.,
Saginaw, Michigan, at pp 2-6 and 2-11.  

 See EPA, Final Report – Volume I of II, Iron and Steel Foundries
Manual Emissions Testing of Cupola Baghouse at Waupaca Foundry in Tell
City, Indiana, at pp. 2-6 and 2-11.  

 As EPA concluded in the Lime Manufacturing NESHAP, the environmental
performance of wet scrubbers and baghouses “seem to us to be largely
in equipoise ....”  69 Fed. Reg. at 404 (January 5, 2004).  We, like
EPA in the Lime Manufacturing NESHAP, are not asserting that wet
scrubbers are better performing than baghouses, but by the same token we
do not believe that the type of performance achieved by baghouses is
better than that achieved by wet scrubbers.

 Following the precedent set by the Lime Manufacturing NESHAP, setting
two distinct standards for facilities within the same category, or in
the alternative by creating a separate category or subcategory,
particularly if it will provide for an overall reduction in air
emissions.

 WI-01 in EPA’s data base.  See Docket OAR-2002-0034

 See  Memorandum, “Emission Factors for Sulfur Dioxide (SO2) from
Cupolas,” from Gary Mosher, AFS, to Kevin Cavender, EPA, dated July
16, 2003, IV-G-21.

 The calculation is straightforward:  1/(1-0.9478) = 19.157. 

 The humidity added to the emissions stream by the wet quench would
interfere with the ability of the baghouse to function properly, and so
it must be removed prior to operation of a baghouse.

 This average removal rate is highly conservative and most likely
underestimates the actual removal achieved high efficiency scrubber. 
However, this value takes into account test data showing 93% as a better
estimate of the SO2 removed by the wet scrubber treatment system at the
Ford facility which results in an average removal of 94.96%.  EPA
estimates a high-efficiency scrubber operates at an efficiency of
approximately 

 We discuss the calculation of the decrease in SO2 emissions resulting
from reductions in the demand for electricity that would result from
replacement of wet scrubbers with bag houses in the next section.

 Memorandum from EPA contractor contained in the Lime Manufacturing
NESHAP docket, item II-B-78, Table 5.  

 Again, these foundries are likely to include a preponderance of
facilities with relatively low SO2 emissions from the cupola prior to
treatment, compared to the emissions from the cupolas currently treated
by wet scrubbers.

 The range depends upon whether the separate standard we seek would be
applied to all existing cupolas with wet scrubbers, or only to a subset
of such existing cupolas.  In any event, the “benefits ratio” is at
least 60% higher in the case of existing foundry cupolas than it was in
the case of lime manufacturing kilns.

 According to Egrid 2002, 2.843% of the nation’s electricity is
generated from oil, and 15.865% is generated from natural gas. 
Therefore, 2.843/(2.843 + 15.865) = 15.2% of the increase in generation
would come from oil-fired generation, and the remainder would come from
gas-fired generation.

 (0.152 * 8.22) + (0.848 * 0.25) = 1.4614 lbs SO2 per MWh;  1.4614 *
129,600/2000 =  94.7 tons. 

 This conclusion is based on an examination of information contained in
the RACT/BACT/LAER Clearinghouse, for coal-fired power plants permitted
since January 2003.  For example, the Whelan Energy Center Unit #2
utility boiler, fueled by sub bituminous coal, has a limitation of 0.12
lb/MMBTU.  At the average heat rate for all coal-fired facilities
contained in E-Grid 2002 (which is based on 2000 data), this translates
to 1.289 lbs/MWh.  Given that the heat rate is undoubtedly far lower for
this newly permitted facility than the average for all existing
coal-fired generators in 2000, the actual rate would be closer to 1.0
lbs SO2 per MWh, which would translate to an offsetting increase of 64.8
tons SO2 due to increased electricity demand.  The MidAmerican Energy
Company’s 790 MW PRB coal-fired boiler received a limit of 0.10
lb/MMBTU, which would translate to an even lower net offset of
approximately 54 tons.  

 The scrubber achieved an average PM emissions rate of 0.01830 gr/dscf
during the testing.   

 The reduction in the recirculation of water resulted in the scrubber
water being both less hot and less concentrated, which substantially
improved the ability of the scrubber to remove SO2.

 Since 46% of the SO2 converts to fine PM, and since the SO2 is oxidized
to SO42+ in the conversion process, the resulting weight of the fine PM
created is 46% of the weight of the SO2 emitted, times (the molecular
weight of  SO42+ divided by the molecular weight of SO2).  Since the
molecular weight of SO42+ is 96, and the molecular weight of SO2 is 64,
the weight of the fine particulate created from SO2 emissions is the
mass of the SO2 times 0.46 times 1.5.

 As will be discussed later, the comparison is even more favorable when
only facilities with both SO2 data and PM data are considered, and
greater still when only relatively large facilities are considered.

 Mass (PM2.5) = Mass (SO2) * 0.46 * (96/64) 

 42 U.S.C. § 7412(d)(3) and § 7412(d)(3)(A).

 42 U.S.C. §7412(d)(1)

 National Emission Standards for Hazardous Air Pollutants for Iron and
Steel Foundries, Proposed Rule, 67 Fed. Reg. 78274 at 78276, December
23, 2002.  

 42 U.S.C. §7412(c)(1).

 The authorization for the Administrator to “distinguish among
classes, types, and sizes of sources within a category” is best
understood as an additional source of authority to create a subcategory.
 The authority to distinguish among classes, types, and sizes of sources
within a subcategory in establishing standards for that subcategory has
not, to our knowledge, ever been utilized by EPA.  Instead, whenever
making distinctions EPA has always used the mechanism of a distinct
subcategory.

 Northeast Maryland Waste Disposal Authority v. EPA, No. 01-1053 (D.C.
Cir., February 24, 2004), slip op. at p.16.  

 It will be substantially easier and less costly for existing cupolas
that have no pollution control equipment to install baghouses than it
will be for those sources that have wet scrubbers, which remove the
great bulk of particulate emissions and a high percentage of SO2
emissions as well.   Moreover, because of the relative size and
complexity of the wet scrubber controls compared to the cupola itself,
removal of the wet scrubber to make installation of a baghouse possible
will require the shutdown of the manufacturing process for substantially
more time than can be accommodated by the annual summer shutdowns over
the next three years.  Replacement of the cupola itself would be an
easier proposition.

 This table was developed by Gary Mosher of the American Foundry Society
based on data developed by EPA on July 9, 2003 and was submitted to EPA
by AFS on August 20, 2003.  

 Comments of the American Foundry Society on the Proposed NESHAP for
Iron and Steel Foundries, February 21, 2003.

 This table was developed by Gary Mosher of the American Foundry Society
based on data developed by EPA on July 9, 2003 and was submitted to EPA
by AFS on August 20, 2003.

 Id. at 77851.

 Under the proposed rule, each existing melting furnace was required to
control emissions of PM to 0.005 g/dscf.   It was more difficult to
identify a bright line distinguishing large and small cupola operations
based on data for individual cupolas.  However, the final rule redefined
the “affected source” so as to cover the entire foundry (i.e.,
“the affected source is each new or existing iron and steel foundry
that is a major source of HAP emissions).  Looking at the entire foundry
as the “affected source”, and thus looking at multiple cupola
operations as a whole, there is a clear bright line between large
multi-cupola operations and other facilities.  This distinction is not
only material to the analysis of similarities and differences between
large and small operations, but looking at the entire facility also
allows for an evaluation of the unique issues faced by foundries that
operate multiple cupolas.  

 Not only is there a natural break in the capacity of the affected
sources, but as discussed elsewhere in the petition, the three largest
multiple cupola affected sources have issues that are unique to their
operations based on their size.  

 Since this Petition is being submitted by the Alliance of Automobile
Manufacturers, the focus shall be on the large source category since it
contains the operations of member companies.  Other than illustrating
that a medium and small “affected source” category could be
warranted, the facilities in the medium and small categories are not
member companies and thus this Petition does not represent these
facilities and thus there is no discussion regarding suggested emission
limitations for these non-member company operations.  

 42 U.S.C. § 7412(d)(3)(B).  

 National Lime Ass’n v. EPA, 233 F.3d. 625 at 631 (D.C. Cir. 2000).

 Comments of the American Foundry Society on the proposed NESHAP for
iron and steel foundries; Docket ID # OAR-2002-0034-0036.

 Economic Impact Analysis of Proposed Iron and Steel Foundry NESHAP,
Final Report, November 2002, EPA 452/R-02-01, p. 1-2.  

Petition for Reconsideration

Iron & Steel Foundry NESHAP

June 21, 2004

Page   PAGE  26 		

Petition for Reconsideration

Iron & Steel Foundry NESHAP

June 21, 2004

Page   PAGE  34 		

Petition for Reconsideration

Iron & Steel Foundry NESHAP

June 21, 2004

Page   PAGE  31