SUMMARY OF PUBLIC COMMENTS AND RESPONSES ON 

SECONDARY ALUMINUM NESHAP

December 14, 1999

National emission standards for hazardous air pollutants 

(NESHAP) were proposed for the secondary aluminum production source 

category on February 11, 1999 (64 FR 6946). The public comment 

period ended on April 12, 1999. Copies of the comment letters have 

been places in project docket A-92-61. Dockets are on file at EPA 

Headquarters in Washington, DC, and at the Office of Air Quality 

Planning and Standards (OAQPS) in Durham, NC. A list of commenters, 

their affiliations, and the EPA docket number assigned to their 

correspondence are given in Table 1.

For the purpose of presentation, the comments have been 

categorized and summarized according to the following subject areas:

1. Applicability

2. Definitions

3. Emission Standards and Operating Requirements

4. Monitoring and Compliance Requirements

5. Impacts
2

TABLE 1. LIST OF COMMENTERS ON PROPOSED SECONDARY ALUMINUM 

PRODUCTION NESHAP

Docket Item Number Commenter and affiliation

IV-D-1 Kevin J. Bald

Corporate Environmental Quality

Reynolds Metals Company

P.O. Box 27003 

Richmond, Virginia 23261-7003

IV-D-2 Kenneth D. Woodrow

Counsel for the Aluminum Association, 

Inc.

Baker & Hostetler, Counselors at Law

Washington Square, Suite 1100

1050 Connecticut Avenue, NW

Washington, DC 20036-5304

IV-D-3 Drek Newton

Naval Facilities Engineering Service 

Center

Code ESC426

1100 23rd Avenue

Port Huneme, CA 93043-4370

IV-D-4 Michael Palazzolo

Alcoa, Incorporated

201 Isabella Street

Pittsburgh, PA 15212-5858

IV-D-5 Dana K. Mount

Director, Division of Environmental 

Engineering

North Dakota Department of Health

Environmental Health Section

P.O. Box 5520

Bismark, ND 58506-5520

IV-D-6 Mike Ling

Director, Dioxin Project

Cambridge Health Project

41 Lee Street, #12

Cambridge, MA 02139

IV-D-7 Jancey Pettit, President

United Group, Inc.
3

4008 NW 14th St.

Topeka, Kansas 66618

IV-D-8 Kevin J. Bald

Corporate Environmental Quality

Reynolds Metals Company

P.O. Box 27003

Richmond, Virginia 23261-7003

IV-D-9 Gail M. Graban

Manager, Environmental Affairs

Century Aluminum of West Virginia, Inc.

P.O. Box 98

Ravenswood, WV 26164

IV-D-10 Andrew Stein, CEO

TST, Inc.

11601 Etiwanda Ave.

Fontana, CA 92325

IV-D-11 Samuel H. Bruntz

Staff Environmental Engineer

Commonwealth Aluminum

1372 State Road 1957

P.O. Box 480

Lewisport, Kentucky 42351-0480

IV-D-12 Gary G. Walker and Daniel L. Twarog

North American Die Casting Association

9701 West Higgins Road, Suite 880

Rosemont, Illinois 60018-4721

IV-D-13 Gerry Smarte

Compliance Manager

Vista Metals Corp

13425 Whittram Avenue

Fontana, CA 92335-2999

IV-D-14 Carl Johnson

New York State Department of 

Environmental 

Conservation

Office of Air & Waste Management

Room 608

50 Wolf Road

Albany, NY 12233-1014
4

IV-D-15 David A. Gallogly

Werner Company

93 Werner Road

Greenville, PA 16125

IV-D-16 Donn W. Sanford

Aluminum Extruders Council

1000 N. Rand Road, Suite 214

Wauconda, IL 60084

IV-D-17 Michael A. Palazzolo

EHS Services North America for 

Alcoa Corporate Center

201 Isabella Street

Pittsburgh, PA 15212-5858

IV-D-18 Kimberly Bowden

Sr. Environmental Engineer

Delphi Automotive Systems

485 West Milwaukee Avenue

Detroit, Michigan 48202

IV-D-19 Robert D. Fletcher, Chief

California Environmental Protection 

Agency

Air Resources Board

2020 L Street

P.O. Box 2815

Sacramento, CA 95812

IV-D-20 Peter J. Maciejewski

Regulatory/Legislative Interface Group

General Motors Corporation

485 West Milwaukee Avenue

Detroit, MI 48202

IV-D-21 Debra J. Jezouit

Counsel to the American Foundrymen’s 

Society

Baker and Botts

1299 Pennsylvania Avenue, NW

Washington, DC 20004-2400

IV-D-22 Steven R. DuBois

Alcan Aluminum Corporation 

Manager Environmental Affairs
5

IV-D-23 Robert P. Strieter

Director, Environmental Affairs

The Aluminum Association

900 19th Street, NW

Washington, DC 20006

IV-D-24 Kelle R. Vigeland

Environmental Engineer

Spokane County Air Pollution Control 

Authority

West 1101 College, Suite 403

Spokane, WA 99201

IV-D-25 Edward J. Campobenedetto

Institute of Clean Air Companies

1660 L Street NW, Suite 1100

Washington, DC 20036-5603

IV-D-26 Michael A. Coffman

Hayes Lemmerz

38481 Huron River Dr.

Romalus, MI 48174

IV-D-27 Tom Tyler

Associate Counsel

Institute of Scrap Recycling 

Industries, Inc.

1325 G Street NW, Suite 1000

Washington, DC 20005-3104

IV-D-28 Terry D. Snell,

The William L Bonnell Company, Inc.

25 Bonnell Street

P.O. Box 428

Newnan, Georgia 30263

IV-D-29 Judith Ann Van Houten

LAN Associates

66 Cuna Street

St. Augustine, FL 32084-3619

for VAW of America Inc.

IV-D-30 Kevin M. Butt

Toyota Motor Manufacturing 

North America, Inc.

25 Atlantic Avenue

Erlanger, KY 41018
6

IV-D-31 Wayne E. Wooster

Goldendale Aluminum Company

85 John Day Dam Road

Goldendale, WA 98620-4689

IV-D-32 J.W. Vinzant

Kaiser Aluminum

1201 Airline Highway 

Baton Rouge, LA 70805

IV-D-33 Steven K. Curreri

IMCO Recycling, Inc.

Central Tower at Williams Square

5215 North O’Conner Blvd., Suite 940

Irving, TX 75039

IV-D-34 Gerry Smarte

Vista Metals Corp

Aluminum Alloys

13425 Whittram Avenue

Fontana, CA 92335-2999

IV-D-35 Joseph S. Viland

Wabash Alloys, L.L.C

4525 W Old 24

P.O. Box 466

Wabash, IN 46992-0466
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1. Applicability

1.1 Comment: Several commenters (IV-D-9, IV-D-17,IV-D-23, 

IV-D-31, IV-D-32) wanted to exempt unvented in-line flux boxes from 

testing and monitoring requirements and suggested regulating them 

via work practices based on the following statements:

1) emissions do not have the potential to exceed the emission 

limit because small amounts (< 0.2 lbs/ton) of chlorine gas flux are 

used;

 2) there is no acceptable method for sampling their fugitive 

emissions, so exclusion from testing and monitoring would improve 

the SAPU concept and substantially reduce costs;

3) they are a pollution prevention design that operate within 

allowable OSHA limits, and should be considered representative of 

the MACT floor when properly installed.

Response: Unvented in-line fluxers are capable of using and 

emitting chlorine and HCl in excess of the HCl emission standard for 

in-line fluxers, 0.04 lb/ton. One manufacturer of unvented in-line 

fluxers specifies a flux rate of 0.92 pounds chlorine per ton aluminum 

(Docket item IV-J-1). The Agency has no reason to believe that 

fluxing at 0.2 to 0.9 lb/ton in an “unvented” in-line fluxer will 

meet the MACT floor level of emissions. Owner/operators can meet 

the emission limit by capturing and venting emissions to add-on 

controls or limiting the chlorine flux input to the fluxer. Limiting 

chlorine flux input to levels below the emission limit and monitoring 

flux addition is a work practice that would avoid the need for testing 

to determine the emission rate. If testing is necessary, testing 

costs may be reduced through like-for-like testing allowed in the 

final rule, i.e., with multiple uncontrolled flux boxes of same 

design and same operating practice, only one need be tested to 

demonstrate compliance.

The commenter’s claim that such units cannot be tested is not 

valid. One unvented flux box at a facility that will be subject to 

this rule has been tested since proposal, and the results reported 

to the Agency (see Docket Item IV-D-40). This particular unit was 

tested by measuring emissions at the point where fluxed metal exits 

the flux box. Another method of testing is to construct a temporary 

enclosure around the fluxer for the short duration of performance 

tests to capture fugitive emissions for measurement purposes (see 

Docket item IV-A-1). Following the performance tests, flux usage 

must be monitored and the flux box operating procedures must be 

maintained to ensure continuous compliance with the SAPU HCl 

standard.

With regard to “unvented” fluxers being a pollution prevention 

design that should be considered a MACT floor, commenters have 
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referred to perceived lower emissions that presumably are achieved 

by lower and more efficient use of fluxing agents. The MACT floor 

technology for control of in-line flux boxes upon which the emission 

limit is based is a lime-injected fabric filter; this technology can 

achieve an emission limit of 0.04 lb HCl/ton aluminum. No data were 

provided by the commenters to demonstrate equal or lower emissions 

from “unvented” fluxers over the full range of input flux as compared 

to vented fluxers with the floor technology.

1.2 Comment: Two commenters (IV-D-31, IV-D-32) state that they 

support the SAPU concept.

Response: The EPA acknowledges this support for the proposed 

SAPU concept.

1.3 Comment: Several commenters (IV-D-5, IV-D-7, IV-D-8, 

IV-D-9, IV-D-11, IV-D-16, IV-D-15, IV-D-17, IV-D-23, IV-D-32, 

IV-D-33) opposed regulation of area manufacturing sources of D/F 

emissions, such as extrusion, die casting, and foundry facilities. 

Another commenter asserted that the EPA assumed area and major source 

D/F emitting processes emit at about equal rates per ton of feed, 

but data available to EPA for side-charge and roll top melters 

processing clean charge show those furnaces are not significant 

sources of D/F as compared to furnaces charging dirty scrap. This 

commenter also contended the EPA assumption that 55 percent of all 

delacquering furnaces are located at area sources was the basis for 

regulating area sources. In comments on the Integrated Urban Air 

Toxics strategy the commenter claimed there were inappropriate 

assumptions and errors in the inventories for 112(c)(6) and 112(k).

Response: The EPA acknowledges the error regarding 

delacquering furnaces in the inventory for the Integrated Urban Air 

Toxics strategy. The EPA recognizes that emissions of D/F from 

affected sources in secondary aluminum production facilities are 

site-specific and depend on the type of materials (scrap) fed to the 

process, flux type, flux rate, and flux practices among other 

variables. For both major and area sources the materials fed to the 

furnace and combustion processes contain varying amounts of oil 

(hydrocarbons) and coatings (hydrocarbons and chlorides). These 

compounds found in scrap containing oils and coatings, as well as 

some fluxes, are D/F precursors. Processes, located at facilities 

that are area sources that use the same feed and flux materials as 

are used at major sources, will emit D/F at levels equal to the same 

processes at major source facilities.

The EPA is not claiming that the total D/F emissions from 

affected sources located at facilities that are area sources are 

equal to the total D/F emissions from facilities that are major 
9

sources. However, there were also other commenters who mentioned 

large numbers of sweat furnaces in their states whose emissions were 

not counted, suggesting there are additional D/F emissions beyond 

those estimated in the national impacts at proposal. The EPA has 

developed an estimate of D/F emissions from sweat furnaces located 

at facilities that are area sources. That estimate is now included 

in the national impact calculations.

1.4 Comment: Numerous commenters (IV-D-5, IV-D-7, IV-D-8, 

IV-D-9, IV-D-11, IV-D-12, IV-D-14, IV-D-15, IV-D-16, IV-D-17, 

IV-D-18, IV-D-19, IV-D-20, IV-D-21, IV-D-23, IV-D-26, IV-D-30, 

IV-D-32, IV-D-33) representing aluminum extruders, aluminum die 

casters, and aluminum foundries stated that their facilities should 

not be regulated because they differ fundamentally from large 

secondary aluminum production facilities and in emission potential, 

particularly D/F emissions. The commenters raised the following 

issues:

1) Extruders encompass a broad spectrum of facilities and appear 

to fall within the broad definition of secondary aluminum production 

facilities, which range from relatively small facilities owned by 

large companies to facilities owned by independent business people, 

many of which the commenter claimed are small businesses.

2) Some extruders, die casters, and foundries use no purchased 

scrap but do use internally generated scrap, while other facilities 

use small amounts of “clean” purchased scrap. Some are concerned that 

regulation may interfere with the effort to recycle at the plant, 

while others who purchase scrap see the regulation as creating a 

disincentive to recycle from outside the plant. 

3) Impurities in scrap are a principal source of D/F 

precursors. The commenters stated that extruders, die casters, and 

foundries cannot be large contributors to D/F emissions because they 

use or process only small amounts of higher quality scrap and do 

limited fluxing. One commenter argued that EPA should exclude 

extruders as small contributors to D/F emissions as in Alabama Power 

vs. Costle, 636 F.2d 323 (D.C. Cir. 1980) using the de minimis 

exception articulated in that case. 

4) Previous EPA publications support the distinction between 

die casters and secondary aluminum production facilities:

a) the Documentation for Developing the Initial Source Category 

List defines secondary aluminum production as facilities that smelt, 

and not including die casters;

b) an EPA New Source Review guidance memo (Memo from Thomas 

Curran, December 1998) states "die casting facilities typically need 

not be considered secondary metal production plants" (the commenters 

argued that this memo acknowledges that die casters could engage in 
10

in-house recycling of castings and not be considered a secondary 

aluminum production facility);

c) the Secondary Brass and Bronze NSPS distinguishes between 

facilities that reclaim brass and bronze and those that create a 

finished product. 

5) Applying the D/F standard to affected sources located at 

facilities that are area sources will subject facilities such as 

extruders, die casters, and foundries to the burden of Title V 

permitting and MACT monitoring and reporting. One of these 

commenters stated that no environmental benefit will be gained from 

regulating area source aluminum production facilities since they 

already meet the emission limitation.

Response: 1) The EPA agrees that based on the definition of 

secondary aluminum production facility and current operations of 

some facilities that are extruders, those extruders would be subject 

to this rule. Numerous comments on the applicability section and 

definitions in the proposed rule were received and after 

consideration of those comments, the EPA has revised those sections 

of the final rule. As part of the revisions, the EPA has concluded 

that aluminum extruding, aluminum die casting, and aluminum foundry 

facilities that process no materials other than a) materials 

generated within the facility, and b) “clean charge” (defined in the 

rule), and that do not operate a thermal chip dryer, sweat furnace, 

or scrap dryer/delacquering kiln/decoating kiln are not secondary 

aluminum production facilities and are exempted from the 

requirements of the rule. Based on comments and information 

received in response to the proposal and subsequent meetings with 

the sources, the Agency believes that most small businesses will not 

fall under the definition of secondary aluminum production facility. 

Those aluminum extruding, die casting, and foundry facilities that 

do purchase or otherwise obtain materials other than “clean charge” 

and/or operate a thermal chip dryer, sweat furnace, or scrap 

dryer/delacquering kiln/decoating kiln are secondary aluminum 

production facilities and are subject to this rule. 

The commenter’s reference to some small facilities being owned 

by large companies is consistent with the EPA’s knowledge that large 

companies in the secondary aluminum production industry engage in 

extruding operations. The commenter also claimed that some 

extruders are owned by independent businesses, many of which are 

small, however no specific quantitative data were provided to assist 

the Agency in assessing potential impacts. The Agency has no 

information indicating that large numbers of small business aluminum 

extruders will be affected by this rule.

2) With regard to the regulation discouraging recycling within 

the plant, the final rule does not prevent facilities that are area 
11

sources from using internally-generated scrap as charge to their 

group 1 furnaces. Regarding purchased scrap, some extruders, die 

casters, and foundries use only small amounts of purchased scrap in 

their operations, while other information provided to the EPA since 

proposal indicates that some of these facilities use more than half 

scrap (purchased, returns, and internally generated) as feed/charge 

in their operations. This range of purchased scrap is typical of 

other secondary aluminum processors from which data were obtained 

to develop the NESHAP. (See Docket Items IV-E-1 and IV-E-2). 

The issue with purchased scrap is the level of contamination 

with D/F emission precursors. The EPA worked with industry 

representatives during the regulatory development phase to establish 

definitions and specifications for purchased scrap that would yield 

lower HAP emissions. Data collected indicated that the percentage 

of oil and coatings in scrap (hydrocarbon and chloride content) 

varies over a large range. No concurrence was achieved on the levels 

of scrap oil and coatings content that would reliably limit the 

processing of D/F precursors from affected sources, nor was 

concurrence achieved on a way to measure these levels of oil and 

coatings. Further, a similar discussion with industry 

representatives failed to reach a consensus on how to define limited 

reactive fluxing, the other important aspect of D/F emission 

potential. The EPA has concluded that facilities in which aluminum 

scrap is processed, whether purchased or otherwise acquired from 

outside the facility, fall within the secondary aluminum production 

source category. 

3) These commenters assert that these facilities are not large 

contributors to D/F emissions because they purchase only small 

amounts of scrap or “clean” scrap, thus limiting the availability 

of D/F precursors in the affected sources. However three factors, 

i) the total quantity of scrap fed to processes, ii) the percentage

of oil and coatings contamination of the scrap, and iii) the flux 

rate, are significant variables that affect generation of D/F 

precursors. As mentioned above, some facilites use significant 

amounts of purchased scrap.

With regard to the comment citing Alabama Power vs. Costle, 

636 F.2d 323 (D.C. Cir. 1980) and requesting de minimis exemption 

for extruders, the Clean Air Act does not provide for de minimis 

exemptions.

4) Documentation for the Source Category Listing states that 

the secondary aluminum production source category includes “any 

facility engaged in the cleaning, melting, refining, alloying, and 

pouring of aluminum recovered from scrap, foundry returns, and dross, 

to form aluminum products such as alloy ingots, billets, notched 

bars, shot, hot metals, and hardeners.” The documentation also 
12

states that the category includes pretreatment processes which 

include drying, burning, and sweating, among others. Although there 

can be differences in operations and products between secondary 

aluminum production facilities and those facilities that are 

primarily die casting, foundry, and extrusion facilities, for the 

purposes of this NESHAP the Agency considers the die casting, 

foundry, and extrusion facilities that use aluminum scrap and other 

coated/painted aluminum bearing materials obtained from outside 

their facilities to be engaging in secondary aluminum production 

operations.

The EPA New Source Review guidance memo (Memo from Thomas 

Curran, December 1998) (Docket item IV-B-3) has, in addition to the 

commenter’s quote, an extensive discussion of the fact that some 

facilities whose primary activity is die casting also perform 

secondary metals production from post-consumer scrap or unspecified 

aluminum scrap. This type of facility was identified in the memo 

as a “nested” secondary aluminum support facility. Such facilities 

also use processing equipment that is defined as an affected source 

under this rule. It is the acquisition of aluminum-bearing 

materials from outside the facility that are not “clean charge,” and 

the presence of affected sources that subject the facility to this 

rule. The difference in products is not the determining factor. 

The final rule clarifies that aluminum die casting, aluminum 

foundry, and aluminum extrusion facilities that process only clean 

charge (as distinct from scrap) are not secondary aluminum production 

facilities (regardless of the remelting of internally generated 

scrap) provided they do not operate thermal chip dryers, scrap 

dryer/delacquering kilns/decoating kilns, or sweat furnaces. 

Aluminum die casting, extruding, and foundry facilities that process 

aluminum scrap, etc., (i.e., materials that are not clean charge) 

from outside the facility in the furnaces are secondary aluminum 

production facilities and subject to the final rule.

5) Regarding the burden of Title V permitting, monitoring, and 

reporting for area sources, the final rule has been changed to provide 

the discretion to individual permitting authorities to defer Title 

V permitting requirements for area source facilities, if those 

facilities are not subject to title V permitting requirements under 

other regulatory actions. At present the permitting authority may 

defer the Title V permit requirement for these area sources until 

December 9, 2004. (In a separate action, the Agency proposed final 

amendments on August 18, 1999 to extend title V operating permit 

deferrals for area sources in five source categories (64 FR 45116).) 

A further change that will reduce the burden for area sources 

is that they will only be required to conduct an initial performance 

test to demonstrate compliance. The requirement to repeat the 
13

performance test every 5 years has been eliminated for area sources.

Facilities that use add-on controls will be required to monitor 

parameters in accordance with their approved site-specific OM&M 

plan. Facilities that are area sources which use purchased scrap, 

but meet the D/F emission limit without add-on controls, i.e. use 

work practices, will also be required to monitor in accordance with 

their site-specific OM&M plan. Their monitoring provisions are 

likely to include a scrap inspection or a scrap certification program 

to demonstrate they are not exceeding the scrap quantity and oil and 

coatings contamination levels, and flux rate established during the 

initial performance test of their group 1 furnace(s).

The environmental benefit of controlling D/F from these 

affected sources is reduction of emissions of an environmentally 

persistent HAP. The benefits of monitoring for those sources who 

meet the limit without add-on controls is continuing evidence that 

the operating practices used during the compliance tests are 

maintained and emissions remain at a level below the limit. 

1.5 Comment: Commenters (IV-D-8, IV-D-9, IV-D-23, IV-D-31, 

IV-D-32) desired to allow new or reconstructed units into the SAPU 

and encourage EPA to do it with a discount applied to the new unit’s 

allowed emissions. The commenters stated that:

1) It will allow sources to take advantage of the more 

efficient fluxing achievable in new flux boxes, in particular the 

“unvented” flux boxes.

2) It promotes pollution prevention and is consistent with 

common sense initiatives and project XL innovations, that allow 

plant-wide applicability limits.

3) It is not standard avoidance, but a more effective way of 

complying.

Response: To allow new or reconstructed units into a SAPU 

consisting of existing units would involve combining control 

requirements for new and existing sources for which there is no legal 

construct under the Clean Air Act. Therefore, EPA will not allow 

new units to become part of a SAPU comprised of existing units. In 

order for new units to have the same benefits available to existing 

emission units, the Agency has revised the rule to allow for a SAPU 

that is composed entirely of simultaneously constructed new sources 

and/or simultaneously reconstructed sources, in addition to SAPU for 

the existing emission units.

1.6 Comment: In comments on combining and treating emissions 

from existing sources with those from new sources in a single control 

system:

1) One commenter (IV-D-8) asked to group an existing or new 
14

furnace with a new in-line fluxer as a separate affected source 

(outside the SAPU). The combined unit would have the same limits 

as the furnace by itself for PM, HCl, and D/F (i.e. no emission 

increment for the new in-line fluxer). The industry claimed a 

significant improvement in fluxing efficiency with much lower 

emissions are associated with moving fluxing from the furnace to 

in-line fluxers.

2) Another commenter (IV-D-23) requested that the rule be 

expanded to affirm that new emission units may be ducted to existing 

control systems, if capacity is available or can be expanded to 

accommodate the new source.

Response: The problem with combining a new affected source 

with an existing affected source is that the new source is required 

to meet the specified emission limits, but once combined, the new 

source emissions are not measurable separately from the emissions 

from the existing source. As noted in the response to the previous 

comment, there is no legal construct under the Clean Air Act that 

permits combining control requirements for existing and new sources, 

therefore the combination of an existing furnace and new in-line 

fluxer is not permitted.

The revisions to the final rule do provide for the establishment 

of a SAPU composed entirely of simultaneously constructed new 

emission units. This will allow the combination of a new furnace 

and new in-line fluxer as a SAPU, but not allow combining a new furnace 

or in-line fluxer with an existing SAPU.

1.7 Comment: One commenter (IV-D-7), a manufacturer of sweat 

furnaces, expressed concern about economic impacts on small 

aluminum reclamation operators. This commenter estimated that 

there are at least several hundred sweat furnaces manufactured by 

them being currently used nationally with capacities considerably 

less than the model sweat furnace used in EPA’s analysis of impacts 

(5,000 tons/year). All of their furnaces are equipped with integral 

afterburners. This commenter also submitted an afterburner 

performance test report showing 97.8 percent removal of PM by the 

afterburner and claimed, but did not have measurements, that D/F 

removal should be similar. The commenter stated that the preamble 

did not show D/F results upstream of the afterburners or what 

destruction efficiency was achieved.

Another commenter (IV-D-5) attached a brochure from a 

manufacturer claiming to have distributed over 2000 small sweat 

furnaces. This commenter states that the proposal underestimated 

the number of these sources. The commenter believes that testing 

and control costs will eliminate small businesses from the market, 

and suggested that regulations for area sources be withdrawn until 

small business, health and environmental impacts have been 
15

reassessed. One commenter (IV-D-14) suggested a technology-based 

standard for area source sweat furnaces with no testing required. 

Response: The EPA has no test data to support a comparison 

between PM and D/F removal efficiencies. The D/F emission limit in 

the proposed and final rules has been proven to be achievable with 

MACT floor technology.

Based on the information contained in these comments, the EPA 

requested additional information and data from sweat furnace 

manufacturers to further assess impacts of regulating D/F emissions 

from the furnaces. The large number of units reported to be 

manufactured suggested large numbers of these affected sources are 

currently in operation. The EPA’s further investigation found that 

although one manufacturer who commented only sells sweat furnaces 

with integral afterburners for emission control, that is not the case 

for all domestic manufacturers.

Due to the large number of these sources and the types of scrap 

materials processed, their D/F emission potential is significant 

both individually and in the aggregate. Recognizing this, the EPA 

considered additional regulatory strategies for sweat furnaces and 

performed an economic analysis to examine the impacts of those 

strategies. The conclusion from this analysis is that the cost of 

measuring D/F emissions from sweat furnaces through a performance 

test is significant in comparison to the cost of the furnace and 

afterburner. Based on this analysis the EPA has revised the rule 

to add an alternative means of compliance. Owner/operators electing 

to install and operate an afterburner meeting the design criteria 

of operating temperature of at least 1600 F and a 2 second residence 

time will not have to conduct performance tests. The final rule 

retains the numerical standard so that owner/operators with control 

equipment that does not meet the design criteria have the option to 

test to show that the D/F emissions are below the limit. These 

revisions to the proposed rule, combined with many anticipated State 

permitting authority decisions to exercise their discretion to defer 

the requirement for title V permits, will significantly reduce the 

burden for both large and small businesses operating sweat furnaces. 

The economic impact analysis conducted for this regulation reports 

minimal economic impacts to owners and operators of sweat furnaces.

1.8 Comment: One commenter (IV-D-32) states that the 

applicability language for area sources "and is an area source of 

D/F" could be misinterpreted, and should be replaced by "and is an 

area source operating certain emission units or affected sources with 

D/F limits in this rule."

Response: The preamble makes clear that area source status is 

determined on a facility-wide basis. Facilities subject to the rule 
16

which are area sources, are subject to regulation of only those 

affected sources for which a D/F limit is established, without regard 

to the actual or potential mass of D/F emitted.

1.9 Comment: One commenter (IV-D-3) states that the rule is 

confusing as to its coverage of group 2 furnaces and recommends that 

the rule be revised to clarify that group 2 furnaces are affected, 

except those in SIC 336 (facilities that use only clean aluminum and 

aluminum foundries).

Response: The applicability section of the rule has been 

clarified to indicate that aluminum extruding, aluminum die casting, 

and aluminum foundry facilities that process no materials other than 

materials generated within the facility and clean charge and that 

do not operate a thermal chip dryer, scrap dryer/ delacquering 

kiln/decoating kiln, or sweat furnace are not subject to the rule. 

These facilities, without regard to SIC codes, are exempt even if 

they use reactive fluxes and/or process internally generated scrap 

containing oil and/or coatings. Group 2 furnaces located at 

facilities that are area sources are not affected sources under this 

rule.

1.10 Comment: One commenter (IV-D-14) states that they would 

like applicability clarified and that it is much more straightforward 

to simply state up-front that the rule applies to all chip dryers, 

scrap dryers/delacquering/decoating kilns, sweat furnaces etc., 

regardless of the pollutants that are emitted from the source. The 

commenter states that at present there is a question of whether a 

test showing zero D/F emissions would exempt a facility. 

Response: The rule has been clarified to indicate that all 

operators of sweat furnaces and all operators of thermal chip dryers 

and scrap dryers/delacquering kilns/decoating kilns at secondary 

aluminum production facilities, are subject to the rule. If these 

affected sources are located at a facility that is an area source, 

they are subject to those provisions pertaining to D/F testing to 

show compliance with the D/F emission limit (except sweat furnaces 

complying with the equipment standard), operating, monitoring, 

reporting and recordkeeping. A test showing zero D/F emissions 

would not exempt an affected source because parameters would have 

to be established and monitored to ensure continuous compliance with 

the standard.

1.11 Comment: Two commenters (IV-D-8, IV-D-17) state that 

research and development facilities are not exempted from the rule 

but should be; they are to be regulated under a separate NESHAP. 

Response: The final rule has been clarified to exempt R & D 
17

facilities that do not produce salable products.

1.12 Comment: Several commenters asserted that EPA did not 

collect enough information or data from die casting and foundry 

facilities in the regulatory development process to justify 

establishment of standards that apply to their facilities.

1) One commenter stated that EPA did not follow proper 

procedures during development of the proposed regulation because 

neither the commenter nor any of its member companies actively 

participated in the development. The commenter claimed that EPA 

could not have enough information about die casting to justify 

inclusion under this regulation because only two die casters were 

included in the ICR process. The commenter contended that none of 

EPA’s determinations are valid including MACT floor emission levels, 

quantification of emissions, and economic impacts. Further, the 

preamble request for comments from the die casting industry was 

inappropriate because the preamble stated die casters are excluded. 

The commenter does not possess information, estimates, data, and 

detailed analysis on HAPs and is unable to obtain such information 

within the time constraints [of the public comment period]. (IV-D-12) 

2) Another commenter stated that EPA included aluminum 

foundries in the proposal with little if any evidence that aluminum 

foundries generate sufficient quantities of HAPs to require 

regulation. They argued that insufficient foundry data were 

collected for proper consideration. They acknowledged that a few 

foundries may have received the Information Collection Request (ICR) 

and two site visits were made to foundries, but these were incidental 

to the overall information gathering process. The EPA improperly 

assumed foundry processes are similar to other facilities being 

regulated without regard to differences in output such as aluminum 

products from foundries, and the fact that smelters reclaim aluminum 

from aluminum scrap. They claimed that without exclusion of 

foundries from the final rule, the action would surely be held to 

be arbitrary and capricious as is evidenced by a Supreme Court case, 

Motor Vehicles Mfrs. Assn v. State Farm Mut. [463 U.S.29,43(1983)]; 

regulating them without proper factual research and documentation 

is an arbitrary and capricious action. (AFS) 

3) Other commenters stated that D/F emissions are the issue with 

potential to draw die casters and foundries into the NESHAP 

applicability. They stated that EPA does not have any emissions data 

from die casters and foundries that show they emit D/F. Since EPA 

did not test any source at die casters, the area source finding cannot 

be imposed on die casting operations. The conclusion that area and 

major sources...emit D/F at about equal rates per ton of feed is not 

supported by data. The processes and materials fed to die casting 
18

operations are fundamentally different. There should be a way for 

specific facilities to show they are not sources of D/F; the fact 

that clean charge group 1 furnaces have no D/F limit implies this. 

(IV-D-18, IV-D-20)

4) Two commenters state that EPA’s presumption that because 

D/F emissions from a chip dryer (or group 1 furnace) were found in 

a non-die casting facility that means chip dryers at die casters will 

also be sources of D/F is not valid. (IV-D-12, IV-D-26) 

5) One commenter (referring to facilities that are area 

sources) understood from previous discussions with EPA that the rule 

would only apply to those units having D/F emissions, however as

proposed, the rule would require record keeping, labeling, and other 

requirements to continually demonstrate group 2 furnace status if 

the facility has a group 1 furnace. (IV-D-12)

Response: 1) As the commenter acknowledged, at least two die 

casting facilities were included in the initial ICR wherein the EPA 

collected information and data regarding facilities potentially 

subject to the secondary aluminum MACT standards. In addition, 

during the early phase of the regulatory development activities there 

were discussions between the EPA and North American Die Caster’s 

Association (NADCA) staff regarding the nature of operations in die 

casting facilities. Die casting facility operations were described 

as involving the use of “clean” feed materials and low levels of 

fluxing. Based on this description, the EPA was not certain that 

such facilities should be regulated under this rulemaking. Further, 

at the time of these discussions, the area source categories of 

section 112(c)(6) pollutants had not been identified.

As the regulatory process progressed, the 112(c)(6) area source 

listing was published and included secondary aluminum smelting for 

D/F emissions, and more data were collected on secondary aluminum 

operations that generate D/F. Also, meetings and discussions 

continued with die casting and foundry representatives and these 

revealed that there are major sources as well as area sources of HAP 

emissions within these sectors. These sources perform operations 

identical to those of other secondary aluminum processors.

Although the end products of such die casting (also foundry and 

extruding) facilities may be different than those of the facilities 

that are primarily SAPF, the affected source/emission unit 

operations at some of the die caster, foundry, and extruding 

facilities do not differ significantly from those at major source 

SAPF. Those that process purchased scrap contaminated with oil, 

paint, and other coatings have similar potential to emit D/F because 

the precursors are present in the feed, and process operating 

conditions are similar. 

On the basis of the information submitted to EPA during the 
19

public comment period and changes made to the proposed rule that 

narrow the applicability to facilities that are area sources, 

primarily aluminum extruders, die casters, and foundries, the EPA 

believes the number of those facilities subject to the rule to be 

small.

2) This commenter also acknowledged that their industry segment 

was included in the ICR and that two plant visits were made to 

facilities that are aluminum foundries. Similar to the rationale 

above, those aluminum foundries that purchase scrap and process it 

in operations similar to those found at major source SAPF have the 

potential to emit D/F due to the presence of D/F precursors (oil, 

paint, and coatings) on the charge material and similar process 

operating conditions. 

In regard to the question of whether these facilities emit 

sufficient quantities of D/F to be regulated, under section 112(c)(6) 

EPA is required to subject not less than 90 percent of the aggregate 

emissions of D/F to standards (not necessarily control) under section 

112(d)(2) or (d)(4). Those facilities using similar processes and 

feed materials at aluminum foundries (also die casters and extruders) 

are expected to have similar emissions to SAPF and therefore should 

be subject to such standards.

3) The EPA’s statement that secondary aluminum processes 

located at facilities that are area and major sources emit D/F at 

equal levels on a lb/ton basis is a reasonable conclusion for those 

that process like amounts of purchased oily, painted, or coated scrap 

and/or conduct reactive fluxing in melting furnaces; or process these 

materials in thermal chip dryers, sweat furnaces, or scrap 

dryer/delacquering kilns/decoating kilns.

4) Chip dryers process oil-laden (and sometimes painted) chips 

from machining operations and it is reasonable to assume that they 

have D/F emissions based on test data reported in the proposal.

5) The applicability section in the final rule excludes group 

2 furnaces from the affected source list at facilities that are area 

sources. An owner/operator of a group 2 furnace at a facility that 

is an area source is not required to do any monitoring, recordkeeping, 

or reporting related to that group 2 furnace. 

1.13 Comment: One commenter representing an extruder stated 

that it is unfair to automatically include all area sources 

irrespective of size, purchased vs. in-house scrap, types of 

lubricants, and types of fluxes. Three commenters want a 

clarification that only D/F producing units regulated for D/F within 

an area source are subject to the rule and no other HAPs from that 

source must be controlled. One commenter requests that area sources 

be exempted or the comment period be reopened. (IV-D-15, IV-D-16, 
20

IV-D-29)

Response: Facilities that are area sources are subject only to 

those provisions relating to D/F emission standards for the affected 

sources, and the testing, monitoring, recordkeeping, and reporting 

requirements for the same. The rule does not apply to die casters, 

foundries, and extruders, that purchase or otherwise obtain only 

clean charge (and that do not purchase scrap), or that use only 

material generated from within the facility, and do not operate a 

thermal chip dryer, sweat furnace, or scrap dryer/delacquering 

kiln/decoating kiln.

2. Definitions

2.1 Comment: Numerous comments were received on the definition of 

“clean charge.”

1) One commenter (IV-D-23) stated that the definition should 

include as clean charge, outside runaround that is contractually 

ensured to be clean. 

2) Other commenters (IV-D-8, IV-D-31, IV-D-32) stated that 

they support inclusion of “noncoated runaround” scrap in the 

definition, which may have small amounts of lubricant, and that some 

runaround is returned from customers. These commenters stated that 

the rule should allow external, preconsumer, non-coated runaround 

scrap in group 2 furnaces. 

3) Several commenters (IV-D-15, IV-D-16, IV-D-30) requested 

that EPA define noncoated runaround scrap or redefine clean charge 

to allow scrap covered with lubricants or substances low in materials 

that could generate D/F. Many die casters use scrap generated 

on-site (miscast material, defective parts, and cutoffs of excess 

aluminum) that may have inorganic agents (clay or talc) or die release 

agents (heavy waxes or high molecular weight oils) that do not 

generate D/F when burned.

4) Commenters (IV-D-16, IV-D-29) representing extruders also 

wanted to revise the definition to include purchased scrap low in 

materials that contribute to D/F generation.

5) Other commenters (IV-D-12, IV-D-18, IV-D-20) noted the 

proposed definition of clean charge allows only pure aluminum (pure 

aluminum is an incorrect term) that cannot be cast in a die casting 

machine. They stated that the definition of clean charge also 

restricts the use of chips that have not been processed in a chip 

dryer. This is a disincentive for exploration of new technology 

(presses, centrifuges, and washers) alternatives to chip drying. 

Some facilities that do dry chips do not heat to 343C because it may 

oxidize the metal. The temperature to which chips must be heated to 

qualify as clean charge is arbitrary and was not considered with any 
21

input from foundries and die casters.

6) Two commenters (IV-D-23, IV-D-31) recommend that the 

definition include billets and pig.

7) One commenter (IV-D-8) suggests including alloyed aluminum 

in the definition, along with pure aluminum.

Response: As a result of the many comments received, EPA has 

reviewed and reconsidered the definition of clean charge. 

1, 2, 3, and 4) The definition of clean charge at proposal 

erroneously included non-coated runaround scrap which commenters 

wanted clarified to include runaround from outside the facility 

(i.e., external, relatively “clean,” preconsumer, non-coated 

runaround). The commenters acknowledged that the runaround may have 

“small” amounts of lubricant and coatings. Lubricants, oils, and 

coatings are D/F precursors. As explained in a previous response, 

the EPA worked with industry representatives during the regulatory 

development phase to establish definitions and specifications for 

purchased scrap that would yield consistently lower HAP emissions 

when charged to furnaces. Data collected indicated that the 

percentage of oil and coatings in scrap (hydrocarbon and chloride 

content) varies over a large range. No concurrence was achieved on 

the levels of scrap oil and coatings content, or a universal method 

of measuring the scrap content of oils/coatings, that would reliably 

limit the processing of D/F precursors from affected sources. Group 

2 and those group 1 furnaces that are “clean charge” furnaces have 

no D/F emission limit. It is not consistent with the concept of clean 

charge furnaces to allow oil- and lubricant-bearing scrap purchased 

or otherwise obtained from outside the facility to be charged as clean 

charge. For this reason, the Agency has clarified that the 

definition of clean charge includes internally generated runaround. 

Internal runaround is defined in the final rule as scrap material 

generated on-site by aluminum extruding, rolling, scalping, forging, 

forming/stamping, cutting, and trimming operations that do not 

contain paint or solid coatings. Aluminum chips generated by 

turning, boring, milling, and similar machining operations that have 

not been dried at 343 C (650 F) or higher, or by an equivalent 

non-thermal drying process, are not considered internal runaround. 

Clean charge also does not include “runaround” scrap that is 

purchased or otherwise obtained from outside the facility.

Secondary aluminum production facilities may use painted and/or 

purchased runaround in group 2 furnaces by drying or delacquering 

it to meet the definition of clean charge, so as to eliminate the 

possibility of D/F formation in the furnace. Owner/operators may 

also charge painted and/or purchased runaround scrap to uncontrolled 

group 1 furnaces in a SAPU, provided they achieve an initial 

compliance demonstration and operate according to an OM&M plan 
22

approved by the permitting authority. For group 1 furnaces operated 

without add-on controls, the plan would likely include a 

site-specific scrap inspection or certification program of some type 

to indicate the contamination level and to define the percentage of 

scrap in the total furnace charge.

As noted in a response to a previous comment, facilities that 

are primarily aluminum die casters, foundries, and extruders that 

process only on-site materials or clean charge, and that do not 

operate a thermal chip dryer, scrap dryer/delacquering 

kiln/decoating kiln, or sweat furnace are not secondary aluminum 

production facilities and are not subject to this rule.

5) With regard to the use of the term “pure aluminum” in the 

definition in the proposed rule, the definition has been revised in 

the final rule to eliminate the word “pure” as a modifier of aluminum 

and instead describe it as oil- and lubricant-free 

uncoated/unpainted aluminum.

With respect to the issue of chip drying and the potential for 

oxidation of the aluminum, the final rule does not contain a minimum 

temperature requirement for thermal chip drying to make the chips 

“clean charge.” With regard to other chip processing methods, the 

Agency is not precluding new technologies such as presses, 

centrifuges, and washers that may be capable of producing chips with 

no oily residue thus qualifying those processed chips as clean 

charge.

6) The EPA agrees that billets and pig are clean aluminum 

charge. The definition of “clean charge” has been revised to include 

billets and pig.

7) As noted above the definition of clean charge has been 

revised to eliminate the word “pure” from the phrase “pure aluminum”. 

Because all aluminum is alloyed to some extent, EPA declined to add 

alloyed aluminum to the definition.

2.2 Comment: For the definition of “afterburner,” one 

commenter (IV-D-8) prefers the term “oxidizer” to "incinerator." 

They state that “oxidizer” typically refers to a device used for the 

destruction of VOC whereas “incinerator” refers to a device used for 

the destruction of hazardous and infectious waste.

Response: EPA uses “incinerator” and “afterburner” to refer 

to devices that use high temperatures to oxidize organic vapors 

without distinction as to whether the organic vapor is a HAP or not. 

In the proposed rule, both “afterburner” and “incinerator” were used. 

EPA clarified the final rule by using “afterburner” throughout and 

revised the definition of “afterburner” to state that afterburners 

are also known as incinerators or thermal oxidizers.
23

2.3 Comment: One commenter stated that the definition of “chip 

dryer” is a problem. The commenter questioned if coolants are 

included by virtue of being oil/water mixtures. Chips may be coated 

by other chemicals that are not in the definition. Die casters use 

dryers to remove water, machining fluids, and coolants from chips. 

(IV-D-12)

Response: The definition in the proposed rule stated the chip 

dryer is a device that uses heat to remove water, oil, or oil/water 

mixtures from unpainted/uncoated aluminum chips. Coolants and 

machining fluids that contain oil or oil/water mixtures are included 

in this definition. The intent of this part of the definition is 

to include substances that are D/F emission precursors. The words 

“unpainted/uncoated” preclude chips with paint, lacquer, and other 

coatings from this definition. The latter painted/coated chips are 

covered in the definition of “scrap dryer/delacquering /decoating 

kiln”. Because there are other methods of drying chips, for example 

by centrifuging chips, the term “chip dryer” is modified in the final 

rule to “thermal chip dryer” to indicate a chip dryer that uses heat 

to clean aluminum chips.

2.4 Comment: Two commenters (IV-D-14, IV-D-24) requested that 

"D/F" (dioxin/furan) be defined.

Response: The definition of D/F has been added to the 

promulgated regulation. Dioxins and furans (D/F) means tetra-, 

penta-, hexa-, hepta-, and octa-chlorinated dibenzo dioxins and 

furans. The emission limits for affected sources and emission units 

are expressed in terms of D/F TEQ. TEQ was defined at proposal and 

remains in the promulgated rules.

2.5 Comment: One commenter (IV-D-23) states that the 

definition of “dross-only furnace” should be revised to include 

adding salts to feedstock materials because salt is common and was 

included in testing parameters to establish emission limit.

Response: The EPA agrees that salt is commonly added along with 

dross and has revised the definition of “feed/charge” to clarify that 

for dross-only furnaces, the feed/charge includes the addition of 

solid flux.

2.6 Comment: Several comments were received on the definition 

of “feed/charge weight.”

1)Two commenters (IV-D-8, IV-D-23) recommend deleting solid 

fluxes from the definition because they are not part of charge 

materials per se; solid fluxes were not included as charge material 

in MACT emission testing. 

2) One commenter (IV-D-31) recommends monitoring on the basis 
24

on metal cast rather than charged.

3) One commenter (IV-D-24) recommends that EPA either define 

"feed", or else use the term "feed/charge" throughout. 

Response: 1) The definition of feed/charge as proposed 

included solid flux as part of feed/charge. However, the EPA 

intended the measurement of feed/charge to provide a uniform basis 

of aluminum-bearing materials processed in the affected 

sources/emission units from which to calculate allowable emissions 

and determine compliance. Solid flux usage is a relatively small 

weight percentage in comparison to the aluminum-bearing feed 

materials processed. Solid flux has been deleted from the 

definition of feed/charge in the final rule (except in cases relating 

to dross-only furnaces). 

2) The rule has been revised to allow the option of compliance 

demonstrations on a production weight basis as opposed to feed/charge 

basis. If an owner/operator elects to comply on a production weight 

basis, monitoring must also be performed on a production weight 

basis. It is essential to have a consistent basis for establishing 

the emission limit for the SAPU and monitoring compliance.

3) The commenter correctly points out that “feed” was 

sometimes used in the proposed rule when what was intended was 

“feed/charge” weight. The rule has been revised to be consistent 

in the use of the term feed/charge.

2.7 Comment: Two commenters addressed the topic of cover fluxes.

1) One commenter stated that EPA uses the term cover flux in 

the definition of “fluxing.” It is contrary to the requirement for 

sidewell furnaces to do all their fluxing in the sidewell. (IV-D-18)

2) One commenter (IV-D-8) wants to use cover fluxes in group 

2 furnaces.

Response: 1) A definition of cover flux has been added to the 

final rule and the term “cover flux” has been removed from the 

definition of reactive fluxing. The operating requirements section 

of the final rule has also been modified so as to allow the use of 

cover flux in the hearth of a sidewell furnace where the hearth 

emissions are not vented to a control device.

2) The definition of cover flux states that it is used in both 

group 1 and group 2 furnaces. 

 

2.8 Comment: One commenter stated that the definitions of 

group 1 and group 2 furnaces should be revised to clarify that certain 

heat producing units holding or applying heat to aluminum are not 

intended to be included in these definitions. The language melts, 

holds, or processes aluminum scrap, or processes clean charge could 

be interpreted to apply to ingot preheaters (used prior to placement 
25

of ingots in a furnace) or homogenizing ovens which apply further 

heat after material has been melted, cooled, and cast. It does not 

appear that EPA intended to regulate such units and the issue could 

be resolved by modifying the definitions. The commenter suggested 

for group 1, “melts aluminum scrap or holds or processes such scrap 

in molten form” as the alternate language. For group 2 furnaces, 

“melts only clean charge or holds or processes only such clean charge 

in molten form” as the alternate language. (IV-D-28)

Response: The commenter is correct, the EPA did not intend to 

regulate ingot preheaters or homogenizing ovens. Neither of these 

sources are identified as affected sources under this rule. 

2.9 Comment: One commenter stated that group 1 furnaces should 

be individually discussed in the preamble. The commenter asserted 

that the definition of group 1 furnaces is overly broad and should 

have some de minimis level for reactive fluxing and scrap 

contamination below which the furnace is exempt from the group 1 

definition. Instead of being totally exempt from regulation, EPA 

could consider such furnaces part of group 2 and therefore not subject 

to the extensive reporting requirements of group 1 furnaces. The 

commenter argued that EPA should consider a third category of furnace 

allowing a minimal level of reactive fluxing and semi-clean charge, 

these furnaces would not have to apply controls with low actual 

benefit to the environment. (IV-D-18)

Response: In developing this regulation the EPA thoroughly 

reviewed the various combinations of melting, holding, charging, and 

fluxing practices. This review included the wide variations in 

contamination level in feed/charge materials and types and chemical 

characteristics of fluxes. Extensive discussions were held with 

representatives of the industry, and their insights into the effects 

of these variables were solicited. The EPA considered establishing 

more than two groups of furnaces, but concluded there was no basis 

nor data to support, or upon which to establish, further furnace 

categories or floors. No additional data that would change this 

situation have been provided to the Agency. The final regulation

retains only two categories of furnaces, group 1 and group 2. 

2.10 Comment: One commenter (IV-D-11) supports the definition 

of “group 2 furnace.”

Response: The EPA acknowledges this supporting comment. 

2.11 Comment: Two commenters requested that the definition of 

group 2 furnaces be revised to allow reactive fluxing up to 1% by 

weight of the metal produced and charges with less than 5% by weight 

of metal produced of painted and/or coated scrap, otherwise costly 
26

controls would be required for die caster furnaces. (IV-D-18, 

IV-D-20) 

Response: The response to comment 2.1 above clearly presents 

the rationale for not allowing painted and/or coated scrap as 

feed/charge material and reactive fluxing for group 2 furnaces. 

These practices generate D/F emission precursors. 

If the aluminum die casting facilities owned or operated by the 

commenters are not major sources, they may not be subject to the final 

rule depending on the source of their feed/charge materials, fluxing 

practice, and other processes operated at the site (See comment 

response 1.4 and the final rule). 

2.12 Comment: Referring to in-line fluxers two commenters 

(IV-D-8, IV-D-23) wanted the EPA to remove the word “typically” from 

the sentence referring to located in a transfer line from a furnace, 

to avoid including pretreatment units not tested in development of 

the MACT floor technology emission limits.

Response: The EPA agrees with the commenter. The definition 

has been revised to remove the word “typically” (to exclude crucible 

fluxing with aluminum fluoride).

2.13 Comment: One commenter (IV-D-13) stated that the 

definition of in-line fluxers describes different units than those 

used by the commenter. The commenter’s units are large 

semi-stationary structures using small amounts of reactive flux. 

South Coast Air Quality Management District (SCAQMD) requires no 

controls. Due to variations in these units and potential to emit, 

EPA needs to differentiate between different types of in-line 

fluxers.

Response: As noted above, if the commenter is conducting 

crucible fluxing, this operation is not considered to be in-line 

fluxing.

2.14 Comment: One commenter (IV-D-17) states that the 

definition of “lime injection” should be clarified to provide 

consistency throughout the rule; the definition defines it as 

“continuous” but nowhere in the rule is lime injection required to 

be continuous. 

Response: The MACT floor technology upon which the emission 

standards are based for several affected sources and emission units 

includes continuous lime injection. Owner/operators are free to 

meet the emission limits anyway they can, including use of 

intermittent lime addition systems. However, in the final rule, 

lime addition requirements have been specified only for continuous 

lime injection systems. Lime addition requirements for 

intermittent lime addition have been eliminated because it is not 
27

the MACT floor control technology. Provisions for obtaining 

approval for intermittent lime addition and establishing operating 

requirements have been added to the rule.

2.15 Comment: Several commenters (IV-D-8, IV-D-23, IV-D-31) 

recommend adding the word “routinely” to transfer molten aluminum 

to or from another furnace, which would allow molten aluminum 

transfers to and from melter/holders. This is necessary during 

alloy changes and during startup, shutdown, and malfunction events.

Response: The EPA established the melter/holder type of group 

1 furnace for furnaces that do both melting and holding in the same 

furnace, exclusively. An owner/operator who finds it necessary to 

infrequently use a melter/holder for transferring molten metal to 

or from another furnace as a result of a malfunction, startup, or 

shutdown event can cover that situation by including it in the 

facility’s Startup, Shutdown, and Malfunction plan which is required 

to be incorporated by reference into the facility’s Title V permit.

2.16 Comment: One commeter (IV-D-24) states that 

"Melter/holder" is not defined and asked if this is the same as 

"melting/holding furnace."

Response: The term melter/holder, where it was used in the 

proposal package was intended to mean melting/holding furnace.

2.17 Comment: One commenter (IV-D-23) wants to add that 

“produce significant gaseous” HAP emissions to the definition of 

reactive fluxing. Another commenter (IV-D-8) states that the 

present definition discourages the use of low emitting cover fluxes. 

Another commenter states that the definition of reactive flux that 

includes the words “results in a HAP emission” is overly broad; it 

should be defined to allow a de minimis level. Any measurable 

emission of HAP would cause a flux to be termed reactive whether the 

HAP came from the flux or not. (IV-D-20) 

Response: With regard to HAP emissions from furnaces and 

in-line fluxers, the EPA’s analysis of the industry identified the 

existence of a MACT floor technology that reduces HAP emissions from 

fluxing operations. The Clean Air Act does not provide for de 

minimis exemptions when floor controls exist. The EPA has clarified 

the definition of reactive flux to exclude cover flux. The final 

rule includes a separate definition of cover flux and provides that 

cover fluxes can be used in group 1 and 2 furnaces for prevention 

of oxidation. Use of cover flux is not considered to be reactive 

fluxing.

2.18 Comment: Several commenters (IV-D-8, IV-D-9, IV-D-22, 
28

IV-D-23, IV-D-28, IV-D-32, IV-D-33, IV-D-35) propose a long list of 

chloride/fluoride salts (lithium, sodium, potassium, calcium, and 

zinc chlorides, and lithium, sodium, potassium, magnesium, calcium, 

and aluminum fluorides) that would be added to non-reactive list 

(presumably in group 2 furnace definition) based on IV-D-8 

thermodynamic calculations and lab data submitted. Another 

commenter (IV-D-11) disagrees that any flux salt be defined as 

reactive if any level of HAP emissions is detected; sodium and 

potassium fluoride salts should be considered nonreactive. Results 

of emissions tests using fluoride salt flux are summarized by the 

commenter.

Response: Reactive fluxing was defined in the proposed rule as 

the use of any gas, liquid, or solid flux that results in a HAP 

emission. Only argon and nitrogen were specifically defined as not 

reactive and not producing any HAP. The question at issue is whether 

chloride and fluoride salt compounds in flux yield HAP emissions 

(e.g. HCl) when used in emission unit processes. Some commenters 

submitted theoretical calculations based on reactions of pure salts, 

and the results of bench-scale tests to support their assertion that 

the compounds, when used as fluxes would not yield HAP emissions and, 

therefore, should not be identified as reactive fluxes.

The EPA reviewed the calculations and bench-scale results 

submitted and agrees with the theoretical trends estimated by the 

commenters for pure salt compounds (see Docket item IV-B-2). The 

results suggest HCl will not be formed. However, the fluxing agents 

used in actual practice contain proprietary ingredients and are not 

typically pure salt compounds. Furthermore, the furnaces in which 

these fluxing agents are used contain residues from previous furnace 

cycles that are available to react with current furnace cycle 

ingredients. The EPA does not accept the bench-scale test results 

and theoretical calculations submitted by the commenters as 

sufficient evidence that HAP emissions are not produced in the actual 

furnace environment. The Agency is not precluding the possibility 

of a demonstration, with full-scale emission tests at the furnace, 

by which an owner/operator can show that an element or compounds other 

than nitrogen and argon are not “reactive” fluxes.

The emission test data submitted by one commenter (see Docket 

item IV-D-11) involved tests with potassium aluminum fluoride flux 

in a melting furnace processing non-coated runaround scrap and 

delacquered metal feed/charge (a group 1 furnace as defined in the 

final rule). The test results by EPA Method 26A indicated 0.0067 

lb HF/ton of feed for three runs (non-detectable in two runs and 

detectable in one run). In another case, sodium silicofluoride salt 

was added to a holding furnace prior to skimming. Measured emissions 

using a measurement device similar to that used in EPA Method 13A 
29

indicated 0.00057 lb HF/ton of feed.

According to the definitions in the final rule, the melting 

furnace case would be a group 1 furnace subject to PM, HCl, and D/F 

emission standards and performance testing. The presence of 

measured HF emissions, although relatively low, by definition makes 

the latter flux not a “non-reactive” flux and puts the furnace in 

the group 1 category.

2.19 Comment: Several commenters (IV-D-22, IV-D-23, IV-D-28, 

IV-D-35) recommend that EPA establish a procedure by which the owner 

can petition for exclusion of a particular fluxing agent from the 

definition of reactive flux based on laboratory studies, sound 

science, and acceptance by the permitting agency. Another commenter 

(IV-D-33) suggests that EPA develop a lab test for non-reactivity 

that facilities can use in support of a delisting.

Response: The EPA has reviewed the laboratory study suggested 

by one commenter, and supported by others, to provide a means of 

classifying the fluxes as non-reactive. As noted in the previous 

comment, measurements performed at bench-scale on pure salt 

compounds are not sufficient evidence to place the flux on a 

“non-reactive” list. The Agency would accept emission test data 

obtained with EPA reference methods and conducted on full-scale 

furnaces showing no HAP emissions as evidence a flux is non-reactive.

2.20 Comment: Two commenters (IV-D-11, IV-D-23) support the 

proposed definition of reconstruction.

Response: The EPA acknowledges this support for the definition.

2.21 Comment: One commenter (IV-D-11) states that furnace 

rebuilds with no changes in design and capacities should also be 

excluded from reconstruction as routine maintenance. Other 

commenters (IV-D-8, IV-D-31) suggest that routine burner 

replacements are not reconstructions, and that replacements of 

in-line fluxers with like replacement units are not reconstructions.

Response: The proposed and final rule definitions clearly 

state that refractory replacement is routine maintenance and not a 

reconstruction. If a furnace rebuild encompasses more than 

refractory replacement, the determination for reconstruction is 

based on the fixed capital cost of the new components in comparison 

to the cost of a comparable new affected source. The affected source 

in the case of group 1 furnaces is the SAPU as opposed to the 

individual furnace. The EPA considered the comment regarding 

excluding furnace rebuilds with no changes in design and capacity 

from reconstruction, but decided it was not necessary to modify the 

definition of reconstruction in this regard. The emission standards 
30

are identical for new and existing sources in any case. 

The proposed and final rules state that replacement of an 

in-line fluxer with a repaired unit is not a reconstruction. The 

definition in the final rule was modified to make clear that 

replacement of in-line fluxer components (e.g., rotors/shafts, 

burner tubes, refractory, warped steel) is considered to be routine 

maintenance. Routine burner replacements are subject to the same 

capital cost criterion as furnace rebuilds and seem unlikely to cause 

an affected source to become “reconstructed.” 

2.22 Comment: One commenter (IV-D-22) requests a 

clarification of the rule by adding a definition of “combustion zone” 

and modifying the residence time definition so as to allow them to 

demonstrate their design retains scrap dryer/delacquering 

kiln/decoating kiln gases at or above 1,400 F for the required time.

Response: In the definition of residence time, combustion zone 

refers to the reaction chamber of the afterburner in which the waste 

gas stream is exposed to the direct combustion flame and in which 

combustion of the pollutants takes place; and in which a temperature 

at or above the design temperature is achieved. (Typical design 

practice is for this chamber to have a length to diameter ratio of 

2.0 to 3.0 with average velocities of 10 to 50 feet per second 

according to the Air Pollution Engineering Manual [Air and Waste 

Management Association, 1992]). The EPA considered the commenter’s 

request, but decided not to modify the definition.

2.23 Comment: One commenter (IV-D-10) stated that the 

definition for scrap shredders is too broad and should be narrowed 

to exclude “bale breakers” used for safety reasons, enabling furnace 

operators to see the contents of the bale. The commenter believes 

facilities will take them out-of-service if forced to control the 

minimal emissions.

Another commenter stated that the definition of scrap shredders 

should be modified because they shred all types of scrap, not just 

aluminum. It should be changed to “secondary aluminum sizing 

device” or “aluminum charge preparation.” EPA should also clarify 

that those shredders that process de minimis or incidental amounts 

will not be regulated (low percentages of aluminum-containing scrap 

in comparison to total weight processed). (Institute of Scrap 

Recyclers)

Response: The definition in the final rule has been modified 

to clarify that an “aluminum scrap shredder” is the affected source 

as opposed to a scrap shredder. The EPA also agrees with the 

commenter that bale breakers are not intended to be regulated. The 

definition has been revised to state that a bale breaker is not an 

aluminum scrap shredder.
31

2.24 Comment: One commenter (IV-D-23) wants to add the words 

“subject to a D/F limit” to the end of the last sentence, referring 

to the definition of a group 1 furnace in the proposed rule.

Response: Group 1 furnaces are emission units that are part of 

a SAPU and subject to emission standards for PM, HCl, and D/F. The 

definition as recommended by the commenter would not be correct. 

This change has not be made in the final rule.

2.25 Comment: According to one commenter the definitions for 

secondary aluminum production facility, group 1 and 2 furnaces, 

reactive fluxing, clean charge, and chip dryer are all poorly 

constructed and give the impression that die casting facilities can 

or should be regulated. De minimis levels of reactive fluxing should 

be allowed in group 2 furnaces. (IV-D-12)

Another commenter stated that the definitions must be modified 

to distinguish among source types. For example, distinguish between 

facilities making new products from scrap (using processed scrap as 

raw material) from those only making processed scrap from unprocessed 

scrap. Post-consumer scrap must be removed from the list of 

materials, the processing of which subjects the facility to the rule. 

It can be misunderstood to apply to all sorts of scrap materials 

rather than just aluminum recyclables. The commenter also stated 

that more specific terminology should be used in the rule. In 

addition, the definition of secondary aluminum processing facility 

should be modified to avoid regulating scrap recyclers, except those 

that are part of a larger aluminum production operation. (Institute 

of Scrap Recyclers)

Response: The EPA received many comments explaining the 

differences between die casters, extruders, and foundries, as 

opposed to secondary aluminum production operations. Upon 

consideration of these comments, the EPA has revised the definition 

of secondary aluminum production facilities as it may or may not apply 

to die casters, extruders, and foundries in the final rule. The 

definition has been changed such that facilities that process no 

materials other than 1) materials generated within the facility, or 

2) clean charge, purchased or otherwise obtained from outside the 

facility, and that do not operate sweat furnaces, thermal chip 

dryers, or scrap dryer/delacquering kilns/decoating kilns are not 

secondary aluminum production facilities.

Foundries, extruders, and die casters that use external scrap 

are, however, considered to be secondary aluminum production 

facilities under the final rule, and are subject to all appropriate 

major or area source provisions of the rule. The Agency considered 

that an important determining factor regarding who is part of the 
32

secondary aluminum production source category is the recovery of 

aluminum from scrap. The Agency believes that owner/operators can 

reliably identify clean charge as opposed to scrap and thereby 

reliably limit the processing of D/F precursors. The request of 

commenters to allow the use of “clean purchased scrap” in a facility 

not subject to the rule requires generally accepted, verifiable, 

defined limits to distinguish scrap types from a continuum of 

contamination that cannot be converted into acceptable vs. 

unacceptable levels of D/F emissions. Therefore the processing of 

any purchased scrap in an affected source subjects the facility to 

the rule.

2.26 Comment: One commenter (IV-D-32) states that they support 

the use of the “TEQ” definition of dioxin.

Response: The EPA acknowledges support of the TEQ definition.

3. Emission Standards and Operating Requirements

3.1 Emission Standards

3.1.1 Comment: One commenter (IV-D-25) urged EPA to review 

the application of fluoride and chlorine fluxes in the secondary 

aluminum industry and to verify the appropriateness of HCl as a 

surrogate.

Response: Emission limits for HCl were proposed because test 

data indicate that HCl is emitted when chlorine and reactive chloride 

fluxes are used, and the technology representing the MACT floor for 

HCl removal, which was determined to be lime injected fabric filters, 

also achieves MACT floor level removal of chlorine and HF. Although 

some fluoride fluxes are used by the industry, differences in flux 

properties, cost relative to chlorine/chloride fluxes, and 

occupational health considerations related to in-plant particulate 

levels limit the amounts used, thus limiting the potential for HF 

emissions.

3.1.2 Comment: One commenter (IV-D-25) stated that emission 

limits do not reflect limits achievable using currently available 

technology and that neither the limits nor the selected MACT 

accurately reflect MACT. The commenter stated that the MACT floor 

emission levels violate section 112 of CAA in that they are not based 

on the best-controlled sources for new sources and are not at least 

as stringent as the best performing 12 percent for existing sources. 

According to the commenter, EPA should consider, but did not, 

emission limits more stringent than the floor. In a related comment, 

another commenter (IV-D-6) disagreed with the dioxin emission 
33

standards and stated that they are unsupported by emissions data. 

According to the commenter, the method of developing the limit is 

inconsistent with the CAA and fails to recognize the law of averages 

and, in the case of SAPUs, is illegal because it permits individual 

group 1 furnaces to emit dioxin at levels in excess of MACT floor.

Response: The commenters argued that EPA did not properly 

consider the available emissions data in establishing the MACT floor 

emissions limits. In the case, Sierra Club v. EPA (March 2, 1999), 

the DC Circuit held that because MACT standards must be achievable 

in practice, EPA must assure that the standards are achievable “under 

most adverse circumstances which can reasonably be expected to recur” 

(assuming proper design and operation of control technology). Slip 

op. p. 13. The case further holds that EPA can reasonably interpret 

the MACT floor methodology language so long as the Agency’s 

methodology in a particular rule allows it to “make a reasonable 

estimate of the performance of the top 12 percent of units”, slip 

op. p. 7; that evaluating how a given MACT technology performs is 

a permissible means of estimating this performance, id. at 13; and 

that new source standards need not be based on performance of a single 

source, id. The court’s decisions gives EPA latitude in determining 

the MACT floor and the MACT floor emission limits. EPA determined 

the MACT floor based on information available for each affected 

source and emission unit. At proposal the EPA selected emission 

limits at the floor level of control and the commenters provided no 

additional emissions data for any pollutant for EPA to consider. The 

emission standards are based on the emission levels achieved through 

the application of MACT floor technologies and account for variation 

in the process and in the air pollution control device effectiveness.

3.1.3 Comment: One commenter (IV-D-32) stated that they 

generally support the emission limits proposed.

Response: The EPA acknowledges support for the proposes 

emission limits.

3.1.4 Comment: One commenter (IV-D-23) supports the emission 

classes of sources as proposed. Another commenter (IV-D-8) stated 

that they approve of a clean furnace source category and what they 

call a clean in-line fluxer source category. Other commenters 

(IV-D-8, IV-D-32) support the decision not to regulate D/F emissions 

from group 1 furnaces using clean charge

Response: The proposed rule does not refer to a "clean in-line 

fluxer" affected source. Emission limits have not been proposed for 

group 2 furnaces, or for in-line fluxers that operate with no reactive 

flux because these affected sources do not emit HAP. 
34

3.1.5 Comment: One commenter (IV-D-23) supports EPA on the 

selection of pollutants and surrogates.

Response: The EPA acknowledges support for selection of 

pollutants and surrogates.

3.1.6 Comment: One commenter (IV-D-23) supports EPA’s 

selection of MACT floor technologies except for lime-injected FF for 

Group 1 furnaces, which the commenter believes should be 

lime-conditioned FF. However, the emission limits based on lime 

injection are not opposed by the commenter; the preamble should state 

these emission limits are based on above-the-floor technology. The 

commenter supports the work practice standards for Group 2 furnaces 

and supports the decision to not require above-the-floor 

technologies for other sources.

Response: EPA acknowleges the support for the proposed 

standards, however the commenter is mistaken with regard to the floor 

technology for group 1 furnaces. Lime injected fabric filters are 

in use at the best performing 12 percent of group 1 furnaces and thus 

represent the MACT floor.

3.1.7 Comment: One commenter (IV-D-27) stated that several 

of the identified MACT floor technologies are poorly known, or 

potentially unworkable. One scrap recycling firm claimed that a 

lime injection system installed on a fabric filter was unable to 

achieve removal percentages comparable to those specified in the 

rule. One firm has an existing FF that would be very expensive to 

modify for lime injection.

Response: All of the technologies determined to represent MACT 

are in place and operating on the best performing affected sources, 

and have been demonstrated through emission test data to be capable 

of achieving the emission limits. Sources emitting HAP in excess 

of the standards must install or upgrade control devices or implement 

pollution prevention practices to meet the standard.

3.1.8 Comment: One commenter (IV-D-25) stated that EPA 

selected system design criteria that are inappropriate and do not 

necessarily reflect the performance of add-on controls, and that the 

criteria are inconsistent from one application to the other within 

the source category. For example, for fabric filters, air-to-cloth 

ratio is not a good indicator of performance, and the specified ratio 

is high for applications using polyester and woven fiberglass. 

According to the commenter, EPA has used an inventory approach rather 

than assess currently available materials providing enhanced 

performance.

Response: EPA determined the MACT floor technologies based on 
35

information available on control technologies presently in use in 

the secondary aluminum industry. The add-on control design criteria 

discussed in the proposal preamble for the various affected sources 

and emission units are representative of MACT floor technology 

systems. Air-to-cloth ratio and fabric type are two parameters that 

affect performance, but not the only parameters. Add-on controls 

with design parameters other than those cited may also achieve 

emission levels that meet the standards. The commenter provided no 

additional information to establish a different floor nor did they 

provide any performance test data to support a more stringent floor 

for new or existing sources.

3.1.9 Comment: One commenter (IV-D-25) stated that HCl 

emission limits are far above what is actually achievable based on 

emissions data presented. The commenter further stated that 

emission limits should not be specified in terms of feed to the 

process since a properly designed system is capable of limiting total 

outlet emission regardless of feed. According to the commenter, a 

properly designed baghouse with continuous lime injection is capable 

of <15 ppm HCl; this should be the MACT limit.

Response: EPA does not have sufficient data to conclude that 

a concentration standard of 15 ppm can be consistently achieved under 

all operating conditions expected within the industry, and the 

commenter did not provide any data to support their position. 

Performance data from lime injected fabric filter tests indicate that 

these control devices can achieve 90 percent HCl removal rates. 

Under some conditions, a 15 ppm standard may not be achievable with 

MACT floor level control equipment due to variations in processes 

and uncontrolled HCl levels, as explained in the proposal preamble.

 

3.1.10 Comment: One commenter (IV-D-25) is concerned that 

chlorine is being emitted and is not controlled by required systems; 

wet scrubbing is necessary.

Response: Based on recent test reports (see Docket item 

IV-D-36) approximately 98 percent of the chlorine emitted is in the 

form of HCl. Chlorine gas may not be as effectively removed as HCl, 

however, under the final rule, it will be subject to the MACT floor 

level of control. Regarding the commenter’s suggestion that wet 

scrubbing should be required, EPA did not identify wet scrubbing as 

MACT for either existing sources or new sources.

3.1.11 Comment: One commenter (IV-D-19) stated that they have 

chip dryers and scrap dryer/delacquering kilns/decoating kilns 

without afterburners in California and that EPA's testing program 

may not be adequate to represent the population of sources. They 
36

stated that EPA did not consider increases in NOx (presumably from 

afterburners) in ozone nonattainment areas.

Another commenter stated that the inventory of sources is 

inaccurate. The commenter is aware of at least 6 chip dryers at 

aluminum die casting facilities that were not considered in 

establishing the NESHAP; this calls into question the technical 

evaluation and economic impact analysis. (IV-D-20)

Response: The EPA worked with all affected entities, sent 

information collection requests to facilities in the affected 

industries, and met with the affected industry representatives and 

State agencies to obtain information. The Clean Air Act, Section 

112(d)(3) states emission standards are to be promulgated 

considering “. . . the average emission limitation achieved . . . 

(for which the Administrator has emissions information) . . .” The 

MACT floor technology was determined based on the information 

available to EPA at the time of proposal and no information was 

received following proposal that would justify a revision in this 

determination. The numerical emission limit which can be achieved 

with MACT floor technology has been determined from performance tests 

conducted on affected sources equipped with MACT floor technology.

Taking additional NOx emissions into consideration, the 

afterburner equipped affected sources are still considered to 

represent the best controlled sources which make up the MACT floor. 

However, owner/operators are not constrained to the use afterburners 

to meet the standards.

 3.1.12 Comment: One commenter (IV-D-19) stated that their PM 

standard for non-ferrous metal melting is 99 percent control across 

the control device. They suggested allowing this as an alternative 

PM standard.

Response: The PM emission standard is based on the use of 

fabric filters which commonly achieve 99.9 percent, or greater, 

removal at the floor. The commenter’s suggested alternative limit 

is less stringent than the floor technology and therefore is not an 

acceptable alternative.

3.1.13 Comment: One commenter (IV-D-24) suggested 

consideration of carbon injection for D/F control; a Municipal Solid 

Waste (MSW) facility in their county uses this technology to limit 

emissions to one tenth the emission standard.

Response: No one in the secondary aluminum industry uses 

activated carbon injection, therefore it was not considered for the 

MACT floor. Furthermore, EPA has no data upon which to evaluate 

carbon injection as a beyond the floor control option for the 

secondary aluminum industry. Although activated carbon injection 
37

is not cost effective at this time, industry can use this, or any 

technology they choose, to comply with the D/F emission limit. They 

are not constrained to the use of an afterburner or a lime-injected 

fabric filter.

3.1.14 Comment: Commenters stated that the test program 

carried out by EPA did not investigate process factors that could 

cause D/F emissions in determining which activities to regulate. 

The EPA D/F data for chip dryers did not consider process parameters 

such as the presence of cutting fluids on the chips. Afterburners 

not followed by a fabric filter would have a different temperature 

profile than those with a fabric filter and therefore have a different 

D/F emission potential. One commenter cited the June 1994 EPA report 

on Estimating Exposure to Dioxin-Like Compounds and effects of 

radiant gas cooling on formation of D/F. These factors could cause 

chip dryer D/F emissions to be different. Also, EPA tested only one 

chip dryer to establish the emission limit. (IV-D-12, IV-D-20)

Another commenter stated that D/F emissions data shown in the 

preamble Figure 11 show variation in emissions at a single facility. 

This suggests key parameters affecting emissions were not 

identified; EPA should have adjusted the test program to identify 

the causes of wide variability. The cause might be a work practice 

or operational parameter that should be prohibited for high results 

rather than regulating an entire class. (IV-D-18)

Response: The floor determination and emission limit were 

based on the best data available to the EPA. The variation in D/F 

emissions represents typical chip drying emissions profile due to 

the different levels of contamination of the chips. EPA recognized 

the potential for variability in emissions in establishing the D/F 

emission limit. The commenter provided no additional data upon 

which to reanalyze the emission limit.

3.1.15 Comment: Different types of in-line fluxers are not 

recognized in the rule, specifically semi-permanently sealed in-line 

fluxers that are not vented to a fabric filter are significantly 

different in operation than those described in the rule. (IV-D-27)

Response: The commenter did not provide any information upon 

which EPA could base a decision to establish a separate class of 

in-line fluxers. “Sealed flux boxes” appear to be the same as other 

in-line fluxers and are not really sealed (See Comment 1.1 and 

response). The EPA believes that an in-line fluxer ducted to a lime 

injected fabric filter represents MACT floor technology for this 

emission unit. In-line fluxers are not required to install a control 

device if the owner or operator can demonstrate initial compliance 

by means of a performance test. Also, no emission limits are 
38

established for in-line fluxers that use only nonreactive flux 

materials. These units are required to keep records of the flux 

materials used and submit semiannual certification that only 

nonreactive flux materials are used. Limiting chlorine flux input 

to in-line fluxers is a work practice that also can be used. Sources 

willing to monitor flux addition and assume that all reactive flux 

used is emitted may demonstrate compliance for a SAPU on this basis, 

and avoid the need for testing. 

3.1.16 Comment: Several comments were received regarding the 

format of the proposed emission standards. 

1) Two commenters (IV-D-8, IV-D-23) support EPA’s choice of 

format for emission limits based on lbs/ton; also, they do not oppose 

the concentration based limits for shredders.

2) Another commenter stated that tons produced would be a 

better choice than charge weight as a basis for limits due to the 

burden of charge weighing. (IV-D-27)

3) One commenter (IV-D-25) stated that limits should be in 

gr/dscf instead of lb/ton of feed since performance is defined by 

outlet emissions.

4) Two commenters (IV-D-8, IV-D-23) support the use of D/F 

emissions measured on the basis of TEQ. 

Response: 1) The EPA acknowledges support for the lb/ton 

emission limit format and concentration limit for aluminum scrap 

shredders.

2) Sources that have difficulty determining accurate charge 

weights may instead measure aluminum production weights, recognizing 

that, as a result of refining, the production weight will be lower 

than the charge weight and will result in a somewhat more stringent 

emission limit.

3) The EPA believes that, generally, production based 

standards are preferable to concentration standards (except for 

aluminum scrap shredders, where production rates are difficult to 

reliably determine), because they encourage pollution prevention and 

the achievement of emission limits in the most cost effective way. 

For sources within a SAPU, production based standards permit more 

straightforward calculation of allowable emissions.

4) The EPA acknowledges support for D/F emissions measurements 

on the basis of D/F TEQ.

3.1.17 Comment: Two commenters (IV-D-22, IV-D-23) support the 

method used by EPA to select the limits except for D/F from 

delacquering kilns. Other commenters (IV-D-23, IV-D-33) stated that 

on the basis of their assessment of MACT floor performance, the short 

residence time delacquering kiln D/F standard should be increased 
39

from 0.25 to 0.35 μg/Mg (they supplied data from a facility not 

included in the EPA assessment in a table). Another commenter 

(IV-D-22) supports a limit of 1.0 μg/Mg instead of the proposed 0.25 

μg/Mg.

Response: The numerical emission limit for D/F was based on 

the D/F emissions rate that could be consistently achieved (taking 

into account process variability and control system variability) by 

an affected source equipped with the MACT floor level of control. 

The EPA rejected the additional data supplied by commenters because 

of problems in the measurements of D/F emissions. Furthermore, the 

first test performed at that source met the D/F limit. The limit 

of 1.0 μg/Mg recommended by one commenter is based on a source 

controlled only by an afterburner. Because the MACT floor technology 

for delacquerers is an afterburner and a lime-injected fabric filter, 

the EPA rejects this commenter’s suggestion.

3.1.18 Comment: One commenter (IV-D-6) stated that the 

proposed dioxin emission standard for new scrap dryers and 

delacquering kilns does not include a work practice requirement for 

afterburner operation at 1400 F minimum and a minimum residence time 

of 1 second; these limits were established as MACT.

Response: The proposed rule contained two alternate sets of 

emission standards for these affected sources. To use one of the 

sets of numerical standards, the afterburner must have an afterburner 

an operating temperature of at least 1400 F and a minimum design 

residence time of 1 second. The second set of numerical standards 

does not specify the use of an afterburner with a particular 

temperature and design residence time, however, the Agency believes 

that an afterburner that achieves the more stringent numerical 

standards will necessarily meet or exceed the 1400 F operating 

temperature and 1 second residence time. No matter which set of 

standards the owner/operator chooses for compliance, the operating 

provisions of the final rule require that the afterburner temperature 

be maintained at the performance tested level and monitored to show 

continuous compliance. 

3.1.19 Comment: One commenter (IV-D-7) questioned the use of 

a single test as the basis of the emission limit for sweat furnaces 

and stated that it seems arbitrary and that the preamble did not 

present any uncontrolled emissions data.

Response: The EPA acknowledges that the standard was based 

upon data from one test. The numerical emission limit for D/F was 

based on the D/F emissions rate that could be consistently achieved 

(taking into account process variability and control system 
40

variability) by an affected source equipped with the MACT floor 

control technology. The EPA attempted to get uncontrolled emissions 

data in one test by turning off the afterburner, but self-sustaining 

combustion occurred at 1400F (which is typical of afterburner 

operation) and emission levels were within the range of those with 

the burner on.

3.1.20 Comment: One commenter (IV-D-32) stated that although 

based on limited data, they support the emission standards for rotary 

dross coolers. Other commenters (IV-D-23, IV-D-8) stated that they 

do not oppose the concentration-based limits for rotary dross 

coolers.

Response: The EPA acknowledges support for the emission 

standard and its format for rotary dross coolers.

3.1.21 Comment: Several comments were received on the emission 

standards for group 1 furnaces. 

1) One commenter (IV-D-23) stated that test data in the Culp 

Aluminum report and that in the preamble differ. They stated that 

all new bags were placed in the FF before the test so the data 

represent optimum performance.

2) One commenter (IV-D-6) disagreed with dioxin limit for new 

and existing group 1 furnaces as not representative of MACT. They 

stated that at expected stack temperatures, dioxin will be condensed 

on PM. According to this commenter, a lax particulate HAP standard 

(8 times higher than than SCAQMD BACT for group 1 furnaces) will 

increase total dioxin emissions.

3) One commenter (IV-D-6) disagreed with allowing the charging 

of PVC and neoprene coated scrap, dioxin precursors, to uncontrolled 

sidewell furnaces.

4) One commenter (IV-D-23) supported the option of 0.4 lb 

HCl/ton or 90 percent reduction.

5) According to several commenters (IV-D-11, IV-D-22, IV-D-23, 

IV-D-33, IV-D-35), EPA needs to clarify the regulation so that hearth 

emissions from group 1 sidewell furnaces are not included unless 

fluxing is performed in the hearth.

6) Other commenters (IV-D-18, IV-D-20) stated that reactive 

fluxing should be allowed in the hearth of sidewell furnaces without 

requiring control of hearth emissions, otherwise metal oxides build 

up in the hearth and the efficiency of the furnace is reduced. More 

metal is lost when dross is skimmed and the cost of operations will 

increase. Work practices and pollution prevention could be used to 

minimize emissions from these operations.

7) One commenter (IV-D-24) stated that a facility in their 

district is operating with 10 melters feeding 8 holders. All fluxing 
41

is done in the holders. They interpret the rule to mean that the 

holders are not subject to D/F limits, but they have found that D/F 

from the holders is about the same as from the melters. They suggest 

subjecting clean charge furnaces that flux to the D/F standard based 

on their data.

Response: 1)The preamble data were preliminary. The final 

data were slightly different, but were lower for HCl emissions and 

thus provide even stronger support for an emission limit at least 

as stringent as proposed. Also, sources are free to replace filter 

bags prior to initial and periodic performance tests, and are 

expected to replace bags between performance tests (and conduct other 

maintenance operations) as necessary for proper operation and to 

maintain control device performance.

2) Some fraction of the D/F present in the particulate matter 

control device will be adsorbed on the particulate matter (PM). The 

EPA has no data upon which to estimate this fraction and none was 

provided by the commenter. The D/F emissions are controlled by dry 

lime injection and maintenance of the temperature at the inlet to 

the FF. More than 99.99 percent of the PM is expected to be 

controlled by a FF representative of the MACT floor level of 

particulate matter control. The PM emission limit is based on the 

emission rate that could be consistently achieved (taking into 

account process variability and control system variability) by an 

affected source equipped with the MACT floor control technology.

3) As described by the commenter, the furnace would be subject 

to the emission limits for a group 1 furnace. The final rule permits 

emission units within a SAPU to operate without control devices 

(although most sidewell furnaces are controlled) if the complete SAPU 

can demonstrate compliance with the emission standards through a 

performance test. This performance test must be conducted at the 

highest load or capacity reasonably expected to occur. Sources must 

establish initial compliance during a test with scrap containing the 

highest level of coatings and oils that the owner/operator plans to 

charge to the furnace (emission unit). The EPA expects that furnaces 

charged with large amounts of oily and coated scrap will be 

controlled. Uncontrolled emission units must operate within the 

limits of an approved site-specific operating and monitoring plan 

to ensure continuous compliance with the SAPU emission limit. 

4) The EPA acknowledges support for HCl emission limits.

5) Although the EPA agrees with the commenters in that hearth 

emissions are not subject to control unless reactive fluxing takes 

place in the hearth, the EPA did not revise the rule because the 

operating requirements make it clear that control is necessary only 

if reactive fluxing is performed in the hearth.

6) Sources using reactive flux in the hearth of sidewell 
42

furnaces are required to control emissions emissions of D/F, HCl, 

and PM. The final rule definitions make clear that solid salts added 

as cover fluxes to prevent oxidation are not considered reactive 

fluxes.

7) This commentor did not provide any data to support their 

contention. The EPA already had data on the referenced facility and 

had used it for proposal in determining that holders with clean charge 

and reactive fluxing do not require emission limits for D/F. In 

addition, the facility in question has already installed the floor 

controls (a continuous alkaline injection system with a fabric 

filter) to control HCl and PM emissions. This is the same floor 

technology for furnace D/F emissions. 

3.1.22 Comment: The following comments were received on the 

melting/holding furnace emission standards:

1) One commenter (IV-D-32) stated that although based on limited 

data, they support the emission standards for melting/holding 

furnaces.

2) Two commenters (IV-D-8, IV-D-23) supported the method used 

by EPA to select the limits except for HCl for melter/holders. They 

argued that the proposed melter/holder limit will restrict 

operational flexibility in producing high purity alloys in a 

melter/holder as compared to separate furnaces. They also claimed 

they have provided EPA data clearly supporting at least 0.6 lb/ton 

and request a limit of 0.6 lb/ton. Other commenters (IV-D-31, 

IV-D-33) suggested increasing the melter/holder HCl limit to 0.6 

lb/ton.

3) One commenter (IV-D-31) suggested a separate emission limit 

section in the rule for melter/holders.

4) One commenter (IV-D-24) is confused about section 1505(i)(1) 

of the proposed rule. They suggested clarifying language, "Except 

for a melter/holder processing only clean charge,...".

Response: 1) The EPA acknowledges support for the emission 

standards.

2) The EPA has determined that the emissions data support the 

MACT floor level of HCl from group 1 furnaces, i.e., 0.40 lb/ton, 

or 90 percent removal of HCl across a lime-injected fabric filter. 

One of the data sets supporting this emission limit was obtained 

during tests on a furnace with heavy fluxing occurring. None of the 

commenters have provided data indicating that these levels could not 

be achieved with a well operated, properly maintained, MACT floor 

level control device. Also, a source that is unable to meet the 0.40 

lb/ton emission limit for an individual group 1 furnace without a 

control device can comply by meeting the 3-day, 24-hour rolling 

average emission limit for a SAPU.
43

3) The final rule contains a separate paragraph to address the 

PM emission limit for melter/holder emission units. The HCl limit 

for melter/holders is not addressed separately from other group 1 

furnaces because the limit is the same. The calculation of PM and 

HCl emission limits for SAPUs that include one or more melter/holders 

is described in the SAPU emission limit section of the rule.

4) As proposed, EPA intended section 1505(i)(1) (i) -(iii) and 

1505 (i)(2) to apply to group 1 furnaces, except for melter/holders 

processing clean charge at facilities that are major sources; 

1505(i)(1)(ii) to apply to group 1 furnaces, except for 

melter/holders processing clean charge at facilities that are area 

sources, and 1505(i)(3) to apply to group 1 melter/holders processing 

clean charge. This section has been rewritten to clarify EPA’s 

intent. 

3.1.23 Comment: Although based on limited data, one commenter 

(IV-D-32) supported the emission standards for flux boxes. One 

commenter (IV-D-8) stated that the PM and HCl limits for in-line 

fluxers are too tight, which will discourage the use of new in-line 

fluxers and cause sources to flux in the furnace to get the higher 

SAPU limit (and not install an APCD for the new in-line fluxer). This 

commenter thinks that the determination of the lime baghouse as the 

MACT floor for in-line fluxers is technically accurate but will 

discourage the use of in-line fluxers and result in increased 

emissions. The commenter wanted no PM limit on in-line fluxers and 

stated that EPA has not made the case that an emission limit is 

necessary to limit HAP metals. The commenter stated that the 

requirement has a bad cost effectiveness. The same commenter wanted 

no limit, only work practices, for unvented in-line fluxers. The 

commenter stated that the standards for in-line fluxers did not 

account for capture efficiency and should not apply to fugitive 

sources.

Response: The EPA has determined that the MACT floor technology 

for new in-line fluxers is a lime-injected FF. Emission limits have 

been promulgated based on the level of emissions that can be obtained 

on a consistent basis when MACT floor control technology is applied. 

Sources may demonstrate compliance with the HCl and PM standards 

without the installation of a control device through a performance 

test. The promulgated standards are based on the MACT floor. New 

unvented in-line fluxers must achieve the MACT floor level of 

emissions, regardless of whether those emissions are discharged 

through a stack or are fugitive. Sources may not avoid compliance 

merely by eliminating capture equipment and converting stack 

emissions to fugitive emissions. 
44

3.1.24 Comment: The following comments were received on SAPUs:

1) Several commenters (IV-D-8, IV-D11, IV-D-23, IV-D-32) 

supported the establishment of the SAPU which affords some compliance 

flexibility; the equations to calculate limits are also supported.

2) One commenter (IV-D-31) wanted individual compliance 

provisions for emission units as an alternative to SAPU compliance.

3) One commenter (IV-D-17) stated that the 3-day, 24-hour 

rolling average for SAPU is problematic as a result of reduced 

operating schedule on weekends and suggested revising the 

requirement to a 7-day, 24-hour rolling average. Other commenters 

(IV-D-11, IV-D-31) recommended a monthly basis similar to monthly 

basis for determining compliance for primary aluminum reduction 

plants. Another commenter (IV-D-32) supported the emission 

standard based on a 3-day, 24-hour rolling average, which provides 

flexibility for facilities to use the most efficient techniques to 

control overall emissions.

4) One commenter requested monthly compliance 

demonstrations, rather than compliance by cycle or each 24 hours. 

This commenter notes that some processes have cycles greater than 

24 hours. (IV-D-8)

5) Two commenters (IV-D-17, IV-D-32) stated that the cross 

reference to required information in section 63.1505(l)(3)(i) of the 

proposed rule is incorrect; should be (l)(2) rather than (m)(2).

6) One commenter (IV-D-24) stated that in section 1505(a) of 

the proposed rule (emission standards), they are confused about the 

reason for excepting SAPUs.

Response: 1) The EPA acknowledges support for the SAPU 

provisions.

2) The preamble to the final rule includes language which 

explicitly states that a source that demonstrates that all existing 

emission units within a SAPU are in compliance with the limits for 

group 1 furnaces and in-line fluxers, has established that its SAPU 

is in compliance with the SAPU emission limits.

3) The EPA considered other averaging times and concluded that 

the 3-day rolling average is an appropriate averaging time. Based 

on test data, individual emission units have the capability of 

complying on a batch-by-batch basis. Because of the different cycle 

times, and overlapping cycles, a three day, 24 hour rolling average 

provides a meaningful way of representing the emissions 

contributions from the assemblage of emission units within the SAPU.

4) The EPA recognizes that some processes may have cycles 

longer than 24 hours, but this is not typical. The establishment

of compliance demonstrations based on one cycle or 24 hours is related 

to the period of time over which the data were collected during 

performance tests. To establish a longer period for compliance 
45

requires development of longer-term performance information not 

currently available to EPA. Emission limits based on monthly 

compliance periods would necessarily be lower than those limits 

established for one cycle or 24-hour periods based on the averaging 

time involved. 

5) The EPA agrees with the commenters and has made the 

correction.

6) In the proposed rule the emission standards for SAPUs were 

written differently than the other standards because the SAPU could 

comply on a 3-day, 24-hour rolling average basis. The exception is 

not needed; the paragraph has been revised in the final rule.

3.1.25 Comment: One commenter (IV-D-11) supports no emission 

limits for group 2 furnaces.

Response: The EPA acknowledges support for no emission limits 

for group 2 furnaces.

3.1.26 Comment: Two commenters stated that the selection of 

facilities tested did not represent the entire regulated community 

because no die casting and foundry operations were tested. They 

claimed that EPA did not solicit sufficient information from die 

casters and foundries through the ICR process. They stated that only 

one set of tests per operation is insufficient to establish 

standards, the test data obtained were severely limited and 

statistically weak, that operational parameters and conditions were 

not presented, nor a determination of representativeness of the 

industry. They also questioned how one set of data can be used to 

develop emission limits for chip dryers. (IV-D-18, IV-D-20) 

Another commenter claimed that EPA has no basis to assume that 

die caster chip dryers emit D/F at levels requiring control. 

(IV-D-26) 

Two other commenters stated that emission standards and 

operating requirements were developed without reference to die 

casting, foundry facilities, and scrap recyclers and that this acted 

to bias the data. (IV-D-20, IV-D-27)

Response: Many meetings were held during the regulatory 

development process with relevant industry associations, thus 

providing them with the opportunity to participate in the development 

process, and some die casters were included in the ICR activity. In 

discussions with die casting industry staff early in the project, 

representatives of the industry stated that they charged only clean 

materials to their processes, thus leading EPA to conclude at that 

time that their portion of the industry would be unlikely to be 

subject to the rule. Subsequently the Agency obtained additional 

information that indicated some aluminum die casting, foundry, and 
46

extrusion facilities do operate sources using purchased scrap. 

These sources are similar to those operated in facilities whose 

primary purpose is secondary aluminum recovery. 

Much of the test data on which the emission standards are based 

were collected in a test program developed, and at sites selected 

through discussions with industry staff as representative of the 

affected sources and with MACT floor control systems in place. The 

test program covered the full range of furnace operations including 

operations that are representative of those facilities at die casting 

and foundry facilities. Therefore the data are representative of 

emissions from die casting and foundry facilities which perform the 

same process operations and which use the floor technologies/work 

practices and/or pollution prevention measures. These data were 

considered in establishing the numerical emission limits which could 

be consistently achieved through application of MACT floor 

technology. Also, at proposal, the Agency requested any additional 

data from die casting and foundry facilities relevant to HAP 

emissions from affected sources that might be small businesses and 

which processed offsite scrap as well as additional information on 

major sources. Commenters provided no additional test data which 

would indicate a decreased potential for D/F emissions from die 

caster chip dryers, relative to chip dryers operated at other types 

of facilities, nor were D/F emissions data provided for potentially 

affected sources at other die caster and foundry facilities. No data 

provided indications that small business were impacted. The 

response to Comment 1.4 in the applicability section of this document 

explains why D/F emissions are expected from the foundry and die 

casting facilities that use purchased scrap. 

3.1.27 Comment: Two commenters stated that EPA’s testing 

program was insufficient to justify setting numerical limits because 

only one chip dryer was tested. EPA chose not to set limits for other 

nonferrous metal industries because of insufficient data. The 

commenter cited the Background Information Document for the 

Secondary Lead NESHAP (60 FR 121, June 23, 1995). They argued that 

it cannot be sufficient for EPA to set a D/F limit on chip dryers 

using data from tests of a single emission point if six tests at three 

lead facilities is not sufficient data and gives no technical basis 

to regulate. The inventory reported in the April 1998 draft of "The 

Inventory of Sources of Dioxin in the United States" assigned low 

confidence to emissions estimated for secondary aluminum operations, 

but medium confidence for emissions estimated for secondary lead. 

(IV-D-18, IV-D-20)

Response: As noted in the response to the previous comment, 

the sites for testing were selected jointly by EPA and industry 
47

through discussions and meetings with industry staff. The chip 

dryer site selected was equipped with the MACT floor technology and 

was representative of the affected sources, chip dryers charging oily 

chips. The emission limits are based on the level of pollutant 

control which EPA believes to be consistently achievable by affected 

sources employing the MACT floor level of control, taking into 

consideration affected source variability and control device 

variability. 

3.1.28 Comment: One commenter (IV-D-13) recommended that EPA 

provide for alternative means of compliance. The commenter stated 

that the local agency requires 99 percent PM removal for baghouses, 

instead of the standard’s mass per unit of production. Methods of 

compliance should allow for differences in production rates, type 

of scrap melted, amount of reactive flux actually used, baghouse 

inlet loading, and actual measured emissions.

One commenter supported alternate requirements for area 

sources. They stated that limits and control requirements need to 

be reasonably applied. Permitting agencies should have the 

discretion to classify sources as insignificant or fugitive within 

clear guidelines. NESHAP rules anticipated the possibility of 

giving states authority to exclude area sources from controls that 

should not apply, or to establish alternate limits and practices. 

Some equipment may meet source definitions, but does not emit HAPs, 

or there are no visible or fugitive emissions. The commenter stated 

that these sources could be reviewed and classified insignificant 

by the state permitting authority. (IV-D-27)

Response: In regard to the first part of the comment, EPA notes 

that fabric filters are routinely capable of removing greater than 

99 percent of PM and that a mass per unit of production was selected 

for the very reason that it does allow for the variations cited by 

the commenter. It is also permissible for States to have different 

requirements as long as they are not less stringent.

In regard to the second part of the comment, since EPA has 

established limits for facilities that are area sources, States as 

delegated authorities must enforce the MACT limits or more stringent 

limits. The Clean Air Act does not provide for de minimis emission 

thresholds when a MACT floor exists. Control devices are not 

required for affected sources which can demonstrate through 

performance tests that they are in compliance with the numerical 

emission limits equivalent to the application of MACT floor 

technology. In the absence of performance tests and monitoring, EPA 

has no means of establishing that sources are in continuous 

compliance with the emission limit representing the MACT floor level 

of control. 
48

3.1.29 Comment: One commenter (IV-D-9) disagreed with EPA’s 

assumption that pollution prevention will be limited to type of scrap 

charged and the type and amount of fluxing agent used and argued that 

MACT floor equivalence is achievable through furnace design, 

production controls, and revised operating practice. According to 

the commenter, the rule does not adequately support innovative design 

and alternative operating approaches as means to limiting emissions 

as opposed to reliance on control systems.

Response: The EPA agrees with the commenter that furnace 

design, production controls, and revised operating practices, in 

addition to type of scrap charged and fluxing practices, can all be 

used to meet the MACT floor emission limits. The proposed rule, as 

well as the final rule, allows the use of any approach to achieve 

compliance. Sources may demonstrate compliance, by performance 

tests, with the standard by any means, including pollution prevention 

or alternate control devices. Sources must monitor appropriate 

parameters to demonstrate compliance between tests.

3.1.30 Comment: One commenter (IV-D-11) is concerned that the 

rule does not address situations where commonly ducted sources have 

different emission limit formats, e.g., lbs/ton expressed on an 

instantaneous basis vs 3-day, 24-hour rolling average lbs/ton basis.

Response: Sources may be vented to a common control device if 

the same pollutants are being controlled and the standards are on 

a lb/ton basis. For other existing sources, such as delacquering 

kilns and furnaces ducted to a common FF, a case-by-case compliance 

demonstration is required with the permitting authority providing 

approval of the test plan before the tests are conducted.

3.1.31 Comment: One commenter (IV-D-17) stated that the 

equations in 63.1505(k) and Table 1 should be clarified to note that 

“feed rate” in “total tons processed” should be used for batch 

processes.

Response: In order for the calculation to yield the emission 

limit in the proper units, i.e., mass of emissions per unit of charge, 

the feed rate must always be expressed in mass per unit of time. If 

total tons processed is used, it must be over a specified period.

3.2 Operating Requirements

3.2.1 Comment: Several commenters (IV-D-8, IV-D-22, 

IV-D-23, IV-D-32) did not want an exceedance of an operating 

parameter to be a violation of an operating requirement. According 

to the commenters:
49

1) The rule is not clear as to what constitutes a violation of 

the operating requirements.

2) Operating parameters are only indicators of process and 

control performance, not a direct measure of excess emissions.

3) An exceedance should not to be a violation until six 

exceedances occur in a 6-month period.

4) No more than one violation should be counted per 24 hour 

period for any one parameter.

5) The rule is not clear on whether a failure to take corrective 

action in response to an exceedance is a violation of the standard.

6) A failure to initiate corrective action within 1 hour should 

constitute a violation.

7) The rule should specify that if corrective action is begun 

within 1 hour and completed in accordance with the startup, shutdown, 

malfunction (SSM) plan, no violation has occurred.

Response: 1)The language in the final rule has been revised 

to make clear that a deviation of an operating parameter is a 

violation of the operating requirements. Each owner/operator is 

required to define the compliance parameters to be monitored in their 

OM&M plan. Then, during the initial performance tests they are 

required to monitor and establish the value or range of the 

parameters. These values must be reported in the results of the test 

and notification of compliance status to the permitting authority 

and must be approved by the permitting authority. During subsequent 

operations, if the monitored parameters exceed the values or fall 

outside the range determined during the initial performance test, 

it is a violation of the operating requirements of the standard 

(unless it is the result of a malfunction to which the facility 

responds to in accordance with the SSM plan).

2) The owner/operator may use CEMs as a direct measure of the 

emissions rather than using operating parameters if such CEMs can 

be demonstrated to the satisfaction of the permitting agency to 

reliably measure emissions.

3) The EPA has no basis for allowing six deviations before 

considering the facility to be in violation. The owner/operator has 

ample opportunity to establish a range for the operating parameters 

and must thereafter operate within that range.

4) Any deviation of an operating parameter limit is a violation 

of the operating standard, regardless of when it occurs, unless it 

is the result of a malfunction to which the owner or operator responds 

in accordance with the SSM plan.

5) and 6) The rule requires corrective action as a result of 

an operating parameter deviation or bag leak detector alarm. 

Corrective action must be conducted in accordance with the OM&M plan. 

Failure to take corrective action and to complete corrective action 
50

as expeditiously as practicable, is a violation of the operating 

requirements.

7) A deviation that is the result of a malfunction, to which 

the facility responds in accordance to its SSM plan, is excluded as 

a violation.

3.2.2 Comment: Related to the corrective action requirements 

after deviations from process or add-on air pollution control 

equipment operating parameter values or ranges, one commenter 

suggested replacing "deviation" with "excursion" and "deviates" with 

"experiences an excursion from". According to the commenter this 

will avoid confusion with Title V program requirements to report 

deviations from permit requirements.

(IV-D-28)

Response: Sources that must obtain a Title V permit will have 

the process and add-on air pollution control equipment operating 

parameter values and ranges incorporated in their Title V permit. 

As a result there is no opportunity for confusion. Unless a 

deviation results from a malfunction, a deviation under the 

regulation is also a deviation under the Title V permit.

3.2.3 Comment: Several commenters (IV-D-17, IV-D-18, 

IV-D-20, IV-D-22,IV-D-23) disagreed with the requirement that 

capture and collection systems meet the criteria established by the 

American Conference of Governmental Industrial Hygienists (ACGIH) 

for hooding and ventilation systems. The commenters claimed EPA has 

not shown that MACT floor facilities’ hooding and ventilation systems 

met ACGIH criteria so that the requirement is arbitrary; EPA should 

show that the facilities met the ACGIH criteria. Several commenters 

(IV-D-1, IV-D-23, IV-D-31) stated that because EPA has no data to 

support the requirement for ACGIH criteria for capture and collection 

equipment for existing sources, they recommended the requirement 

only apply to new sources. Other commenters stated that although 

currently protecting work space air quality, most existing systems 

would not meet ACGIH criteria meaning significant expenditures to 

upgrade those systems. EPA did not likely account for these costs 

in their economic analysis; they agree with the commenters who stated 

that the requirement should be limited to new or modified sources. 

(IV-D-18, IV-D-20)

Response: For affected sources and emission units that require 

an air pollution control device, a capture and control system meeting 

ACGIH criteria is necessary for occupational safety, and to meet the 

emission standards. The emission standards are based on systems 

that effectively capture and contain emissions at the source 

(minimizing fugitives) and convey them to the control device for 
51

removal. In addition, a capture and control system meeting ACGIH 

criteria with good hooding design will result in a lower volume of 

exhaust air to be treated, and in many cases, a smaller, lower-cost 

control device. EPA considers an ACGIH capture and collection 

system to be part of MACT floor technology for affected sources with 

add-on controls.

3.2.4 Comment: One commenter (IV-D-32) supported not 

counting false alarms of the bag leak detection system in the alarm 

time. Another commenter (IV-D-25) stated that the monitoring and 

reporting requirements are reasonable in order to confirm 

compliance, with exception of bag leak detectors. The commenter 

stated that a facility should not be penalized for rapid response 

to an alarm and recommends that the actual time be counted and delete 

the 1-hour minimum alarm time. 

Response: The rule has been clarified so that false alarms are 

not counted. Alarms that occur during conditions covered by the 

facility’s startup, shutdown, and malfunction (SSM) plan also are 

not counted. A one hour minimum has been retained in the final rule 

to encourage proactive fabric filter maintenance. This provision 

does not penalize the owner/operator if action is started in 

accordance with the facility’s OM&M plan within one hour.

3.2.5 Comment: Several commenters (IV-D-1, IV-D-9, IV-D-10, 

IV-D-17, IV-D-18, IV-D-20, IV-D-22, IV-D-23, IV-D-27, IV-D-32) did 

not want the labeling requirement. They argued that:

1) The inspectors can get this information from the OM&M plan 

in the office before entering the plant.

2) The labels will be hard to maintain in a plant environment.

3) It creates opportunity for violation with no commensurate 

benefit and increases/duplicates regulatory paperwork.

4) The labeling requirement generates safety concerns.

Response: The EPA believes that labeling requirements are 

necessary for enforcement and operating purposes, and should be 

retained due to the complexity of the industry and the numerous 

possible facility configurations (and emission units that could be 

combined within a SAPU). Labeling will help prevent operators from 

charging the wrong materials or improperly operating the units and 

will help inspectors in identifying units and determining if the 

units are being properly operated. However, EPA understands 

industry’s concerns over the implementation of the labeling 

requirements and has revised the rule to require labeling only at 

those affected sources and emission units that can be operated in 

more than one mode and/or which are physically very similar, 

including group 1 furnaces with and without add-on controls, group 
52

2 furnaces, scrap dryer/delacquering kilns/decoating kilns, and 

in-line fluxers. In addition, the rule requires that labels contain 

only the identification of the unit and the applicable operational 

standards. These revisions respond to industry’s concerns 

regarding increased regulatory paperwork with no commensurate 

benefits while maintaining enforceability of the standards, since 

both operators and inspectors will clearly know the operating 

standards/requirements of each emission unit.

 

3.2.6 Comment: Several commenters (IV-D-11, IV-D-17, 

IV-D-23, IV-D-31, IV-D-32,) disagreed with requirement to maintain 

the same flux injection schedule as used in performance test. One 

commenter (IV-D-32) stated that they should be given flexibility to 

develop schedule procedures during performance tests subject to 

approval by the permitting authority. According to one commenter 

(IV-D-11), the requirement to maintain the same flux injection 

schedule as used in performance test, which would be done under worst 

case conditions, would result in an increase in HCl emissions and 

cause other negative environmental impacts. Another commenter 

(IV-D-17) stated that this requirement will cause increased HCl 

emissions for uncontrolled group 1 furnaces and will restrict work 

practices to minimize chlorine use. The commenter suggested a 

separate provision to maintain the same flux injection schedule for 

baghouses with semi-continuous lime feed systems.

One commenter (IV-D-31) wanted flux monitoring on a monthly 

basis and the schedule requirement eliminated. The rule could be 

interpreted to preclude a system with computerized monitoring of 

furnace operations/controls with correlated emissions and online 

continuous emissions calculations.

Response: Owners or operators are required to conduct 

performance tests under the highest load or capacity reasonably 

expected to occur. This is represented by the maximum reactive flux 

rate. The final rule provides that sources may flux (on a lb per 

ton of feed/charge basis), up to the limit established during a 

successful performance test and does not require maintaining the same 

schedule. The rule also does not require owners or operators to use 

more flux than necessary to produce a saleable product. These 

requirements will not lead to increased HCl emissions.

Reactive flux monitoring on a monthly basis is not acceptable 

in that it is inconsistent with the emission standards based on 3-day 

24-hour rolling averages and the established monitoring parameter 

values or ranges derived during the performance test. Monitoring 

over a period consistent with the basis of the emission standards 

provides the necessary evidence of continuous compliance.

The issue of flux injection rate and schedule is related to lime 
53

injection practice for the FF control systems. The final rule 

provides operating requirements for the floor technology, continuous 

lime injection systems with lime-injected fabric filters. 

Owner/operators who want to use intermittent lime feed systems (as 

opposed to continuous injection) must show compliance with the 

emission limits and must apply to the permitting authority for 

approval of an alternative lime addition monitoring procedure. The 

owner/operator must provide information as necessary to show that 

the applicable emission limits will be achieved on a continuous 

basis.

The rule does not preclude the use of computerized systems that 

correlate controls and operating practices with emissions and 

calculate emissions on a continuous basis once this approach is 

approved by the permitting authority and incorporated into the 

site-specific OM&M plan.

3.2.7 Comment: Several commenters (IV-D-11, IV-D-17, 

IV-D-22,IV-D-23) disagreed with the +25 F associated with the inlet 

temperature limit for FF established during the initial performance 

test. According to two commenters (IV-D-17, IV-D-23) the operating 

temperature of these FF will vary more than 25 F due to changes in 

ambient temperature. This creates an unnecessary risk of violation 

and provides no environmental benefit. Another commenter (IV-D-11) 

stated that instead of the temperature requirement, electrochemical 

HCl sensors for automatic lime feed adjustment and other automatic 

systems should be considered to allow greater operating flexibility. 

One commenter (IV-D-17) stated that in-line fluxers are not regulated 

for dioxin emissions and therefore do not need a temperature limit.

Response: The final rule has been changed to eliminate this 

requirement for fabric filters used only to control in-line fluxers 

since these units operate at temperatures that are close to ambient 

temperature. For other affected sources and emission units, or 

fluxers ducted to a device cocontrolling other emission units, the 

+25 F limit is retained. Operators commonly use dilution air or 

water sprays as required to maintain the FF inlet temperature within 

the range. Also, performance tests could be conducted at worst case 

conditions. For example, performance tests could be conducted so 

that the inlet temperature is much higher than the normal operating 

inlet temperature (450 F vs 380 F, for example) thus providing a 

larger operating range. Dioxin formation is strongly influenced by 

the temperature at the FF inlet, and temperature control is the means 

of preventing D/F formation (and enhancing HCl removal) in the fabric 

filter. Temperature is also a parameter which is monitored to ensure 

continuous compliance between periodic performance tests. This is 

because it is an indicator of control device performance for D/F and 
54

HCl emissions.

3.2.8 Comment: According to one commenter (IV-D-32), owners 

and operators could demonstrate compliance with the HCl emission 

limit by monitoring total chlorine input and showing it to be less 

than the emission limit.

Response: The EPA agrees, for in-line fluxers and group 1 

furnaces processing only clean charge, operators may demonstrate 

compliance with the HCl emission standards (in lieu of performance 

tests) by demonstrating that reactive flux injection is limited to 

a rate which would not exceed the SAPU standard if emitted in its 

entirety. However, the operators must also show the affected 

sources or emission units are meeting the PM limit as well. 

3.2.9 Comment: One commenter (IV-D-24) stated that there are 

two sections 1506(g)(2) in the proposed rule.

Response: The commenter is mistaken.

3.2.10 Comment: One commenter (IV-D-31) wanted a SAPU wide 

bubble on flux and lime monitoring.

Response: Flux and lime monitoring is required to ensure that 

emissions do not increase above the level measured during a 

successful performance test. A SAPU wide bubble would, for example, 

allow all of the flux to be added to one furnace and all of the lime 

to a FF controlling a different furnace. This would not ensure 

continuous compliance with the standard, and would permit affected 

sources and emission units to operate with less than the MACT floor 

level of control. 

3.2.11 Comment: Several commenters (IV-D-17, IV-D-22, 

IV-D-23) agreed with the selection of temperature as an operating 

parameter for FF used on group 1 furnaces and delacquering/drying 

kilns with FF, but disagreed with requirement to maintain the inlet 

temperature within +25 F of the performance test value. Two 

commenters (IV-D-17, IV-D-23) claimed most FFs operate in range of 

300-350 F to protect bags and want to allow 50 F above that 

determined during performance test instead of 25 F. They stated 

that EPA has not shown that HCl adsorption is a strong function of 

temperature at 350 F. One commenter (IV-D-22) recommended that the 

temperature simply be limited to 400 F. One commenter (IV-D-11) 

further disagreed with the requirement to maintain temperatures for 

delacquering kiln afterburners and fabric filters relative to the 

established average temperatures.

One commenter (IV-D-6) stated that the 25 F operating tolerance 
55

is arbitrary and there is no evidence that this will not result in 

dioxin emissions in excess of standard. They stated that EPA should 

require worst case performance testing and not permit sources to 

exceed the control device inlet temperature of the performance test.

Another commenter (IV-D-17) stated that the language in section 

63.1506(g) of the proposed rule to monitor the inlet temperature of 

fabric filter needs to be rewritten to be more clear. 

Response: There is evidence to suggest that D/F formation is 

strongly influenced by temperature in the FF. There is no assurance 

that an affected source that meets the standard at one temperature 

will continue to meet the standard at a higher temperature. The rule 

allows a 25 F tolerance in recognition of the potential time lag in 

temperature sensing and control system response. Operators are free 

to conduct performance tests under worst case conditions, e.g., 

350 F and then operate 300 F to achieve a 50 F window, or to upgrade 

temperature control systems to maintain the FF inlet temperature 

within the 25 F tolerance under all conditions.

3.2.12 Comment: One commenter (IV-D-10) stated that the 

requirement for continuous lime injection for FF will generate 

excessive quantities of potentially hazardous waste to be 

accommodated by declining landfill capacity. They stated that lime 

precoating on finer mesh polyester bags may be just as effective and 

that continuous feeding does not ensure continuous injection because 

feeders become clogged. Another commenter (IV-D-13) is concerned 

about the requirement to add lime to baghouse continuously since 

their current practice is to inject lime at the beginning of 24 hour 

melting cycle; at the end of the cycle, bags are cleaned and fresh 

lime is added. They stated that the pressure drop across filters 

is monitored and when the pressure reaches a predetermined limit, 

melting is halted or bags cleaned and new lime is added. The commenter 

is uncertain as to how to add lime continuously and questioned the 

need to do so because only a finite amount of lime can be applied 

to bags and the rest would be wasted.

Response: Continuous lime injection is the MACT floor 

technology upon which the emission limits are based. The operating 

requirements in the final rule are tailored to continuous lime 

injection systems. Operators may use batch injection or another 

technology with the approval of the permitting authority, and if they 

can demonstrate compliance with the emission limits. Operators may 

conduct performance tests under intermittent lime addition 

conditions and maintain intermittent lime addition at performance 

test conditions when approved in advance by the permitting authority. 

The rule includes requirements for determining if continuous lime 

feeders are clogged and corrective action in the event that they are 
56

not operating properly. 

3.2.13 Comment: One commenter (IV-D-17) stated that the cross 

reference to emission standards for group 1 furnaces without add-on 

controls in 63.1506(n)(3) is incorrect; it should be 63.1505(i)(3) 

rather than (2). One commenter (IV-D-24) pointed out an error in 

1506(n)(3); the reference should be to 1505(i)(1) and (3).

Response: These references have been corrected in the final 

rule.

3.2.14 Comment: One commenter (IV-D-9) recommended allowing 

furnace redesign as a compliance alternative for group 1 furnaces.

Response: Operators may use any means they choose to comply 

with the emission limits. If a successful performance test is 

conducted without the use of a control device, the source is not 

required to install a control device.

3.2.15 Comment: One commenter (IV-D-31) wanted site-specific 

monitoring for uncontrolled emission units.

Response: A source may develop (with the approval of the 

permitting authority) alternate monitoring procedures for emission 

units within a SAPU or affected sources without add-on controls. 

3.2.16 Comment: Several comments were received on the 

feed/charge weight requirements.

1) One commenter (IV-D-17) stated that the requirement for 

feed/charge weight determinations (63.1506(d)) should be revised to 

be consistent with the Part 70 operating permit program and 

recommended language to that effect.

2) One commenter (IV-D-32) supported the flexibility provided 

by feed/charge weight options but stated that the facility should 

also be allowed to substitute production weight for feed weight. 

This would cause the denominator for emission rate calculation to 

be smaller and therefore give a conservative measure of compliance.

3) One commenter (IV-D-31) wanted facility-wide charge weight 

monitoring. 

4) One commenter (IV-D-31) wanted charge weight monitoring 

frequency to be site-specific.

Response: 1) Accurate determination of charge weight is 

required to ensure compliance with production-based standards. 

Sources that are unable to meet the charge weight measurement 

tolerances established in the rule may apply to the permitting 

authority for approval of alternate monitoring procedures.

2) Operators are permitted to substitute production rate for 

charge weight and the final rule states this.
57

3) Operators demonstrate compliance for SAPUs based on 

performance tests. Charge weights must be determined on an emission 

unit basis to ensure that the calculations for SAPU wide emissions 

are correct. In addition, flux rate monitoring is based on 

individual emission unit production rates. Control devices must be 

tested under the highest load reasonably anticipated to occur, and 

if production is shifted from emission unit to emission unit, 

performance test data would not be valid, therefore this is not 

allowed.

4) For batch processes, charge weight must be monitored for each 

furnace cycle to properly calculate SAPU compliance, and to determine 

that individual emission units are being operated within established 

parameters.

3.2.17 Comment: Two commenters (IV-D-23, IV-D-32) stated that 

air breaks in ductwork are needed to achieve cooling of gases upstream 

of FFs to protect FFs. They recommended deleting proposed section 

63.1506(c)(2).

Response: The final rule has been clarified to permit air 

breaks in ductwork for gas cooling.

3.2.18 Comment: One commenter (IV-D-17) stated that the 

wording in Table 1 of section 63.1506 of the proposed rule requiring 

corrective action when “any” visible emission occurs, effectively 

prohibits any visible emissions. The commenter recommended 

corrective action when a 6-minute average opacity reading of greater 

than or equal to 5 percent is determined via a visible emissions 

evaluation. 

Response: The commenter correctly interpreted the rule in that 

EPA requires corrective action when a visible emission occurs. This 

is required in instances when a continuous opacity monitor is not 

installed and the operating requirement is periodic visual 

inspection for emissions. The EPA and industry generally concurred 

that no visible emissions occur when the control technology is 

operated properly.

4. Monitoring And Compliance Requirements 

4.1 Monitoring Requirements

4.1.1 Comment: Several comments were received that requested 

more flexibility in the monitoring requirements aimed at reducing 

the burden to the industry:

1) One commenter stated that the operating and monitoring 

requirements of §§63.1506 and 63.1510 are too prescriptive and not 
58

consistent with preamble statements regarding flexibility. 

(IV-D-32)

2) Several commenters stated that EPA should allow alternative 

site-specific monitoring and operating plans to improve feasibility 

and cost effectiveness. (IV-D-9, IV-D-31, IV-D-33, IV-D-35)

3) Another commenter stated that separate provisions should 

be included in each of §§63.1506 and 63.1510 allowing facilities to 

develop alternative procedures approvable by the applicable 

permitting agency. (IV-D-32)

4) Two commenters claimed the provisions will result in 

burdensome, labor-intensive requirements without commensurate 

benefit to the environment. (IV-D-22, IV-D-35)

5) Another commenter with a rolling mill facility claimed 

their plant is operating at demonstrated low emission levels and 

seeks monitoring plan flexibility to allow their facility to continue 

in its present mode. Referring to this plant, another commenter 

stated that the plant has developed a correlation between opacity 

and PM which has been used for over a year, in accordance with a 

regulatory order. This monitoring has been approved by EPA and the 

local agency and is federally enforceable. (IV-D-32)

Response: The final rule has been written to incorporate more 

flexibility in the monitoring requirements:

1), 2), and 3) The final rule includes explicit provisions for 

obtaining approval to use alternative monitoring procedures and 

lists the types of information needed in the application. It 

includes data or information to justify the request such as technical 

or economic infeasibility, a description of the proposed alternative 

monitoring requirements including operating parameters and how the 

limit for SAPUs (if SAPUs are included in the application) will be 

calculated, and information as to how the alternative monitoring 

requirements would provide equivalent or better assurance of 

compliance with the standards.

In addition, in response to the numerous comments received 

regarding the proposed monitoring and operating provisions, the 

final rule has been written to provide more flexibility to individual 

facilities in developing their OM&M plans and for approval of 

site-specific monitoring and operating alternatives, within EPA 

guidelines, by the permitting authority. Additional comment 

responses below discuss some specific changes made in the final rule.

4) The monitoring requirements are necessary to demonstrate 

continuous compliance and, as such, are environmentally beneficial. 

Most, if not all, of the monitoring data collection or logging can 

be computerized and, therefore, will not be labor intensive.

5) Specifically, the final rule allows the owner/operator of 

a plant to apply to the Administrator for alternative monitoring, 
59

if necessary, or document their current procedures in the facility 

OM&M plan. The OM&M plan is submitted to the permitting authority 

for review and approval. The final rule gives more flexibility, for 

example, through guidance for scrap inspections (used in operating 

limits and monitoring) that is less prescriptive and more options 

for lime injection monitoring.

4.1.2 Comment: Several commenters stated that the monitoring 

frequencies and data quality objectives are too restrictive and 

specific for application across a diverse industry and bear no 

relevance to the emission standards or ensuring proper operation of 

emission controls. (IV-D-9, IV-D-22, IV-D-31, IV-D-35,) Another 

commenter agreed with the selection of the monitoring parameters in 

the proposed rule, but stated that the monitoring intervals are too 

frequent. (IV-D-8)

Response: Monitoring frequency requirements are related to 

the need for evidence of continuous compliance, and frequent readings 

are essential to provide the demonstration. However, the final rule 

changes the frequency of recording monitored parameter values from 

that proposed. For example, the frequency of recording fluxing 

rates has been reduced by requiring readings only during periods when 

flux additions are occurring. Additional options included for 

monitoring free-flowing lime change those monitoring and frequency 

requirements and increase the monitoring options. Furthermore, the 

provisions for site-specific OM&M plans approved by permitting 

authorities allow opportunity for adjustment of monitoring, within 

EPA guidelines, to fit site-specific conditions. Comments dealing 

with data-quality objectives for specific monitored parameters are 

addressed in more detail below.

4.1.3 Comment: Several commenters argued that the 

requirements for accuracy of 1 percent when applied to feed/charge 

weight and flux injection rates are overly stringent and burdensome 

and create an unnecessary increment for a violation. (IV-D-1, IV-D-9, 

IV-D-10, IV-D-11, IV-D-22, IV-D-23, IV-D-27, IV-D-32)

Response: The EPA has retained the 1 percent accuracy 

requirement in the final rule. However, the EPA recognizes there 

may be situations in which 1 percent accuracy for feed/charge weight 

and chlorine flux injection rate is not workable. An example of this 

may be operating at a very low flux injection rate. The final rule 

has been written to allow the permitting authority to approve 

alternative accuracy requirements for monitoring equipment, on a 

site-specific basis, in situations where the 1 percent accuracy 

requirement is not workable and where the owner/operator provides 

data/information to substantiate that emission standards will be 
60

achieved on a continuous basis.

4.1.4 Comment: In comments on accuracy of performance test 

measurements and feed/charge weight measurements:

1) One commenter stated that the EPA reference methods are not 

better than 10 percent repeatable, so the requirement for 1 percent 

accuracy in charge weight is arbitrary and unnecessarily burdensome. 

(IV-D-32)

2) Another commenter requested less stringency in the accuracy 

requirement for the sources whose emissions are well under the 

emission limit, noting that the expected accuracy of Methods 26A and 

5 is 10 percent. This commenter suggested that the charge weight 

monitoring be restricted to only those sources having to comply with 

a lb/ton emission limit. (IV-D-8)

3) An additional commenter stated that an aggregate accuracy 

of 5 percent is more representative of reproducible floor practice. 

(IV-D-9)

4) Another commenter wanted the weight monitoring not to be 

required for each emission unit, but allowed to be aggregated across 

emission units. (IV-D-31)

Response: The EPA considered the measurement accuracy issue 

raised by the commenters and addresses their points as follows:

1), 2), and 3) Related to test method accuracy, the EPA notes 

that the variability in the test methods, process, and control 

equipment is incorporated into the testing results upon which the 

emission limits are based. The limits have been established to 

accommodate that variability. Given that the emission limits are 

on a lb-of-emission/ton-of-feed (or charge) basis, it is also in the 

owner/operators best interest to make an accurate weight 

determination because inaccurate measurements could cause them to 

be out of compliance. As noted in the previous response, the final 

rule provides additional flexibility with regard to feed/charge 

measurement in situations where the 1 percent accuracy is not 

workable. 

4) Weight monitoring is required because the emission limits 

are based on lb/ton of feed/charge or product. Under the 

site-specific OM&M plans, individual emission units of the same type 

may have different allowable emission rates based on the presence 

of add-on control devices, fluxing practice, and feed/charge 

practices. The only way to determine compliance is to monitor 

weights for individual emission units. 

4.1.5 Comment: One commenter stated that inspection of lime 

feed systems once per 8-hour shift and more frequently when found 

to be plugged may be difficult, arguing that visual inspection at 
61

silo and bin tops is dangerous. The commenter suggested alternate 

language that reduces the required checks from every 4 hours for 3 

days, if plugged, to checks for only 2 consecutive 4-hour periods 

following restoration to free flow. Another commenter also 

disagreed with the requirement to inspect every 4 hours for 3 days, 

even if the problem is corrected earlier.

Response: Based on the comments received the final rule has 

been written to provide other options to demonstrate free-flowing 

lime. In addition to the option to perform visual checks to verify 

free-flowing lime, the owner/operator may use devices such as load 

cells to demonstrate this via weight changes in lime feed bins, use 

pressure sensors in pneumatic conveying systems to distinguish low 

or "no flow" conditions, continuously monitor lime feed rate, use 

an HCl monitoring device at the fabric filter outlet, or another 

method subject to approval by the permitting authority.

4.1.6 Comment: One commenter requested that lime feeder 

inspection requirements and corrective action requirements 

demonstrate compliance and that discovery and correction of a 

blockage or feeder setting drift not be an automatic violation. The 

commenter suggested that the rule be rewritten to require corrective 

action when necessary and not to make blockage or feeder setting drift 

a violation.

Response: As noted in the response to the previous comment, 

the final rule provides additional options for monitoring the lime 

system to maintain free-flowing lime. One of those options, the HCl 

monitor, provides a direct indication of continued effective 

operation of the control system which is the desired goal of any 

monitoring option selected. Other options that detect lime feeder 

blockages are not direct and immediate performance indicators, so 

the time until remedied is a critical variable. For this reason, 

EPA requires maintenance of free flowing lime in the feed hopper or 

silo at all times. Blockages that occur as a result of equipment 

breakage or failure would potentially fall under the malfunction 

provision, and if determined to be a malfunction, would be covered 

by the SSM plan and would not be a violation, if corrected in 

accordance with the SSM plan. However, continued and frequent 

blockages indicate a system design and operating problem rather than 

a malfunction.

4.1.7 Comment: Several commenters objected to the proposed 

regulatory requirements for scrap inspection programs. They stated 

that the requirements are too onerous, expensive, complex and overly 

prescriptive, and further, some provisions are not technically 

feasible or cannot be reasonably met. Three of the commenters 
62

suggested that the broadly stated scrap inspection requirements 

provided in the preamble to the proposed rule could be acceptable, 

and that approval of site-specific plans by the permitting authority 

would be a more acceptable requirement. Two commenters also stated 

that the scrap should not have to be inspected if the necessary 

control systems are in place. According to these commenters, 

inspection is only needed for control by work practices or pollution 

prevention. They stated that the EPA needs to be clearer as to which 

sources are covered; the preamble says all furnaces and the rule says 

uncontrolled group 1 furnaces.

Response: The scrap inspection program requirements apply 

only to those facilities that elect to use such a program as a 

monitoring technique to ensure the oil and coatings content of scrap 

charged to a group 1 furnace stays below levels established during 

the performance tests. Such a program could apply to facilities that 

have only uncontrolled group 1 furnaces, or facilities that have both 

add-on controlled and uncontrolled group 1 furnaces.

As a result of the numerous comments received regarding the 

scrap inspection program elements, the EPA has modified the proposed 

rule. The detailed requirements contained in the proposed rule have 

been deleted and the general scrap inspection guidelines provided 

in the proposal preamble have been adopted. This change will provide 

more flexibility to owner/operators to tailor the program to specific 

conditions for their facility. The scrap inspection program, if 

selected by the facility, will become part of the site-specific OM&M 

plan. The specific inspection program elements, which must be 

consistent with guidance in the rule, will be approvable by the 

permitting authority as part of the site-specific OM&M plan and will 

be enforceable under the facility's permit.

4.1.8 Comment: One commenter stated that firms would likely 

need to hire additional staff to process paperwork, especially the 

monitoring data recorded every 15 minutes. The commenter argued 

that these requirements have no corresponding benefit to the 

environment; requiring a report to document no exceedances is

unnecessary when the absence of a report of exceedances should 

presume compliance. (Institute of Scrap Recyclers)

Response: The facilities' burden for processing and reporting 

results from monitoring data were included in the impacts estimates 

reported with the proposal package for this rule. Recording data 

every 15 minutes would require few if any additional staff. Data 

logging equipment and software automate this process. Such systems 

may be set up to sound warning devices when monitored levels approach 

or exceed the established operating limits. The requirements to 

process and report results periodically ensures that some staff are 
63

assigned the responsibility to identify problems and take corrective 

actions when necessary, and that a corporate official is obligated 

to report the results of these efforts. The benefit to the 

environment is the continuous prevention of HAP emissions in excess 

of established emission limits.

4.1.9 Comment: Two commenters wanted to establish parameters 

for control devices other than baghouses, lime baghouses and 

afterburners. Wet scrubbers used in one facility illustrate such 

a need. Such alternative monitoring plans could be handled on a 

site-specific basis subject to permit authority review. (IV-D-31, 

IV-D-8) Another commenter suggested provisions for and language 

permitting the use of alternate control devices with site-specific 

monitoring plans. (IV-D-28)

Response: The General Provisions provide for the use of 

alternatives to monitoring requirements or procedures upon approval 

by the Administrator (40 CFR 63.8(b)). Monitoring parameters for 

scrubbers or other alternative control devices can be established 

under this provision. Consistent with the General Provisions, the 

final rule has been modified to specify some procedural requirements 

for applying and obtaining approval of alternative monitoring 

programs. 

4.1.10 Comment: Two commenters requested that the 

requirement to calibrate lime injection rate, flux injection rate, 

and other monitoring instrumentation quarterly should be changed to 

"in accordance with manufacturer's specifications" throughout the 

rule. The EPA requirement may conflict with the manufacturer's 

recommendation. (IV-D-32, IV-D-8)

Response: The final rule has been revised in the appropriate 

sections to require monitoring equipment calibration in accordance 

with the manufacturers' recommended schedule or if no schedule is 

specified at least once every 6-months. It was not EPA's intention 

to have the calibration occur less frequently than that recommended 

by the manufacturers.

4.1.11 Comment: One commenter wants to restrict application 

of the Operation, Maintenance, and Monitoring (OM&M) plan to the 

control device, not the affected source, and the commenter also wants 

to exempt uncontrolled sources from the plan. (IV-D-8)

Response: Although the add-on air pollution control device is 

the means by which emission reductions are ensured for those affected 

sources or secondary aluminum processing unit- emission units vented 

to such a device, process operating conditions for the attached 

sources also affect the level of emissions achieved. It is for this 
64

reason that EPA is requiring the establishment of operating limits 

for process parameters such as flux injection rate. For 

uncontrolled emission units that are part of a secondary aluminum 

processing unit, the level of emissions is directly related to the 

type and amount of flux used as well as the level of contamination 

in the scrap fed, in the case of melting furnaces. It is essential 

that the OM&M plan document the work practices and pollution 

prevention measures that will be used to maintain compliance and that 

these practices and measures then become an enforceable part of the 

permit.

4.1.12 Comment: According to two commenters, by the time the 

rule is finalized most affected sources will have Part 70 or 71 

permits. These two commenters wanted a requirement that the OM&M 

plans be available for review not that they be required to submit 

them as part of the Part 70 or 71 process. The costs would be 

burdensome and were not included in the economic analysis. (IV-D-18, 

IV-D-20)

Response: The proposed rule required the OM&M plan to be 

submitted to the applicable permitting authority as part of the 

application for a Part 70 or 71 permit. Based on the comments 

received and a further review of the proposed requirements the EPA 

is clarifying the requirements for the OM&M plan. As the commenters 

mention, some facilities will already have their permits, so it is 

not feasible for them to submit the OM&M plan as part of the 

application process. Also it was not EPA's intention to have the 

OM&M plan itself incorporated into the permit, such that it would 

be necessary to reopen the permit if changes to the OM&M plan are 

desired. The permit can incorporate the OM&M plan by reference upon 

the plan approval by the permitting authority. The OM&M plan would 

be external to the permit so that a permit revision is not necessary 

when an OM&M plan change is desired. For those plants already having 

permits when the final rule is promulgated, the OM&M plan will be 

incorporated by reference.

4.1.13 Comment: One commenter suggested the requirement for 

verification (of accuracy in feed measurements) every three months 

should worded to be either once per quarter, or else within three 

months of the last verification. This commenter also suggested 

changing the requirement to verify weight calibration every three 

months to a requirement to check it and recalibrate if the error is 

found to be greater than 1%. (IV-D-20)

Response: The EPA has considered this, and other comments 

related to measurement accuracy for feed/charge. The final rule has 

been changed to require verification of the calibration at the 
65

frequency recommended by the manufacturer, or if no calibration 

frequency is specified, at least once every six months.

4.1.14 Comment: One commenter wanted solid flux excluded 

from charge weight. (IV-D-8)

Response: Most of the test data that were used as the basis 

for selection of emission limits for the affected sources and 

emission units were computed on the basis of exclusion of solid fluxes 

from the feed/charge weight. Therefore, this definition is modified 

in the final rule to exclude solid fluxes, except for dross-only 

furnaces. The EPA has determined that it is appropriate to continue 

to include solid fluxes as part of the feed/charge for dross-only 

furnaces. 

4.1.15 Comment: One commenter supported the monitoring 

options provided for fabric filters. (IV-D-11) Another commenter 

wanted Method 9 or daily visual inspection added to the monitoring 

options available for fabric filters (Method 9 is an option for scrap 

shredders, but not other affected sources or emission units). 

(IV-D-23)

Response: The EPA proposed the daily use of EPA Method 9 as 

an alternative means of monitoring compliance for fabric filters and 

lime-injected fabric filters serving scrap shredders due to the 

intermittent nature of shredder operations. The final rule retains 

the requirement for all affected sources or emission units with 

fabric filters or lime-injected fabric filters (other than scrap 

shredders) to install, operate, and maintain a bag leak detector 

system, or install and operate a continuous opacity monitoring system 

to provide evidence of continuing compliance. 

4.1.16 Comment: One commenter suggested alternative wording 

for calibration of the bag leak detection system at 63.1510(f)(1)(ix) 

of the proposed rule to clarify the intent. (IV-D-17) Another 

commenter supported the option to use bag leak detectors that operate 

on principles other than triboelectric. This commenter recommended 

that recording milliamp current be allowed as an alternative to 

output voltage.(IV-D-11) One commenter requested clarification 

that non-triboelectric bag leak detectors can be used. Also the 

commenter questioned whether the EPA guidance is intended to apply 

only to triboelectric detectors. The commenter stated that a 

clarification is needed as to whether record keeping and response 

tests specified in the guidance are required by the rule and whether 

recommended and suggested procedures are required by the rule. 

Details of what is intended to be mandatory and enforceable should 

be provided. (IV-D-28)
66

Response: The guidance referenced in the proposed and final 

rule is intended to apply only to triboelectric detectors. The 

record keeping and response tests specified in the guidance are 

required by the rule. The recommended procedures and suggested 

procedures are also required by the rule. Some flexibility is 

provided in the guidance, so an owner/operator can select an option 

and follow that option.

However, bag leak detection systems based on triboelectric 

principle are not the only type that can be used. For other types 

of bag leak detection systems, the manufacturer's recommendations 

should be followed.

With respect to the requirement to monitor output voltage from 

the system that was in the proposed rule at 63.1510(f)(1)(v), the 

intent was to monitor the electrical signal from the triboelectric 

sensor that indicates relative PM loadings. If the bag leak 

detection system installed uses current or some other type signal 

instead of voltage to provide that relative PM loading, then current 

or the other signal should be monitored instead of voltage.

4.1.17 Comment: Two commenters stated that PS-2 was 

established for SO2 and NOx monitoring systems, not temperature 

monitoring and PS-2 is therefore not applicable. One commenter gave 

six cites for requirements that do not apply or work, stating that 

existing equipment is not suitable for temperature traversing 

because it is not equipped with ports for that purpose. The other 

commenter also stated that adding sampling ports would decrease 

structural integrity of the system and potentially expose workers 

to high temperatures. The latter commenter also requested EPA to 

modify the temperature monitoring device provisions that call for 

use of a NIST reference method (63.1510(h)(2)(v) of the proposed 

rule) to clarify that what is being required is the use of a 

calibration standard, not a reference test method such as those in 

Appendix A, part 60. (IV-D-23, IV-D-17) Another commenter stated 

that the relative accuracy requirements are unnecessary for 

temperature monitoring. (IV-D-11)

Response: The EPA agrees that Performance Specification-2 is 

not appropriate for application to temperature measurement. Based 

on the other comments received, the requirements for the temperature 

monitoring device for affected sources using an afterburner or fabric 

filter have been revised. The final rule requires that the recorder 

response range include zero and 1.5 times the average temperatures 

established as the monitoring parameter and that the calibration 

method must be a National Institute of Standards and Technology 

calibrated reference thermocouple-potentiometer system or alternate 

reference, subject to approval by the Administrator. 
67

4.1.18 Comment: One commenter stated that the proposed rule 

included two sections 1510(g)(2). (IV-D-20)

Response: This assertion is incorrect, there was only one 

section 1510(g)(2) in the proposed rule.

4.1.19 Comment: Two commenters supported options for 

monitoring injection weight, and maintaining and recording injection 

rate. (IV-D-23, IV-D-11)

Response: The EPA acknowledges these comments in support of the 

rule provisions and notes that the final rule also includes a 

provision for obtaining approval of alternate monitoring procedures.

4.1.20 Comment: One commenter stated that inspection of lime 

feed systems once per 8 hour shift and more frequently when found 

to be plugged may be difficult, arguing that visual inspection at 

silo and bin tops is dangerous. The commenter suggested alternate 

language that reduces the required checks every 4 hours for 3 days 

if plugged to checks for only 2 consecutive 4-hour periods when 

restored to free flow. Another commenter also disagreed with the 

requirement to inspect every 4 hours for 3 days, even if the problem 

is corrected earlier (IV-D-23, IV-D-11)

Response: Based on the comments received, the final rule has 

been modified to provide other options to demonstrate free-flowing 

lime. In addition to the option to perform visual checks to verify 

free-flowing lime, the owner/operator may use devices such as load 

cells to demonstrate this via weight changes in lime feed bins, use 

pressure sensors in pneumatic conveying systems to distinguish low 

or "no flow" conditions, continuously monitor lime feed rate, use 

an HCl monitoring device at the fabric filter outlet, or another 

method subject to approval by the permitting authority. 

4.1.21 Comment: One commenter requested that lime feeder 

inspection requirements and corrective action requirements 

demonstrate compliance and that discovery and correction of a 

blockage or feeder setting drift not be an automatic violation. The 

commenter suggested that the rule be rewritten to require corrective 

action when necessary, not to make blockage or feeder setting drift 

a violation.

(IV-D-28)

Response: As noted in the response to the previous comment, the 

final rule provides additional options for monitoring the lime system 

to maintain free-flowing lime. One of those options, the HCl 

monitor, provides a direct indication of continued effective 

operation of the control system which is the desired goal of any 
68

monitoring option selected. Other options that detect lime feeder 

blockages are not direct and immediate performance indicators, so 

the time until remedied is a critical variable. For this reason EPA 

requires maintenance of free flowing lime in the feed hopper or silo 

at all times. Blockages that occur as a result of equipment breakage 

or failure would potentially fall under the malfunction provision, 

and if determined to be a malfunction, would be covered by the 

Startup, Shutdown, and Malfunction (SSM) plan and not a violation, 

if corrected in accordance with the SSM plan. However, continued 

and frequent blockage indicates a system design or operating problem 

rather than a malfunction.

4.1.22 Comment: Several commenters suggested alternatives 

to the manual inspection of lime feed hoppers. One commenter states 

that a facility has installed devices that continuously monitor lime 

feed rate. (IV-D-17) Another commenter states that manual inspection 

should be changed to allow computerized weight loss monitoring and 

demonstration of reliability of alternatives as part of development 

of the OM&M plan. (IV-D-32) A third commenter recommends that lime 

feed pneumatic conveyor blower pressure be monitored to determine 

if lime is free flowing and that a sensor be installed that activates 

an alarm if no lime feed is detected. (IV-D-11)

Response: Based on the comments received, the final rule has 

been modified to provide other options to demonstrate free-flowing 

lime. In addition to the option to perform visual checks to verify 

free-flowing lime, the owner/operator may use devices such as load 

cells to demonstrate this via weight changes in lime feed bins, use 

pressure sensors in pneumatic conveying systems to distinguish low 

or "no flow" conditions, continuously monitor lime feed rate, use 

an HCl monitoring device at the fabric filter outlet, or another 

method subject to approval by the permitting authority. 

4.1.23 Comment: One commenter agreed with need to monitor 

chlorine usage on in-line fluxers and group 1 furnaces without add-on 

controls and to maintain rate at or below the average measured during 

the performance test. (IV-D-11)

Response: The EPA acknowledges support for those provisions 

of the rule.

4.1.24 Comment: Several commenters claimed continuous flux 

measurements are not needed since much of the time during furnace 

cycles there is no fluxing. The requirement for continuous 

measurement and recording 15-minute blocks is an undue burden when 

applied across entire industry. Having data in 15-minute blocks 

does not necessarily yield accurate results. Many facilities only 
69

flux 10 to 30 minutes out of a 5-7 hour cycle and so would be recording 

zero values for 97% of the operating time. Likewise solid flux 

additions and other fluxing may occur in batches. The commenters 

stated that the requirement to continuously measure and record is 

unreasonable and provides no environmental benefit. (IV-D-23, 

IV-D-22, IV-D-17, IV-D-11, IV-D-32) Another commenter stated that 

they will have to measure chlorine before dilution to meet this 

requirement, and thus pipe pure chlorine, rather than a 12% mixture, 

through the plant to each furnace which they view as a safety problem. 

(IV-D-8)

Response: The EPA has reviewed the flux injection rate 

monitoring requirements and, based on comments received, modified 

the requirements in the final rule. As noted by the commenters many 

furnaces do inject flux for only short time periods within a furnace 

cycle and others add solid flux in batches. The monitoring 

provisions have been modified to require recording flux injection 

rate in 15-minute blocks only during periods when fluxing is 

occurring.

The EPA's intent is to achieve high accuracy in the measurement 

of reactive flux usage. The latter commenter mixes flux gases at a 

central location prior to distribution through the plant to eliminate 

the presence of pure chlorine gas in work areas. The weight of 

reactive flux component in the diluted mixture must be measured to 

1 percent accuracy, and the quantity of mixture delivered to each 

emission unit must also be measured to yield an accurate quantitative 

measurement of reactive component used per emission unit during the 

monitoring period. The final rule does not preclude the use of 

central mixing stations for reactive flux gases provided that the 

amount of reactive flux component delivered to each emission unit 

is determined within 1 percent accuracy. As described in the 

response to Comment 4.1.3, the final rule does provide for the 

permitting authority to approve alternative monitoring accuracy 

requirements on a site-specific basis when 1 percent may not be 

workable.

4.1.25 Comment: Several commenters suggested alternatives 

to the flux monitoring requirements. One commenter suggested 

measuring flux cylinder weights before and after casting operations 

for monitoring for in-line fluxers.(IV-D-23) Two commenters stated 

the regulation should provide an option for a site-specific 

monitoring scheme better suited to each operation. (IV-D-22, IV-D-8) 

Another commenter urged EPA to provide monitoring flexibility in the 

form of alternative monitoring techniques. (IV-D-32) One 

commenter suggested an HCl monitor in the waste gas stream to 

automatically control the baghouse lime injection system should be 
70

allowed in lieu of monitoring chlorine flux input. (IV-D-11) EPA 

should allow proper operation of pollution control systems to replace 

continuous weighing of flux salts. (IV-D-11) Other commenters 

requested SAPU bubble monitoring of flux (no monitoring for 

individual emission units) (IV-D-1, IV-D-32). One commenter also 

wanted to drop the fluxing schedule requirements and substitute a 

monthly mass input to the SAPU. (IV-D-8)

Response: The EPA recognizes the wide variety of fluxing 

practices among facilities and within facilities for different 

affected sources or emission units. The purpose of requiring 

monitoring of fluxing rates and flux consumption is to provide 

continuous verification that the practices (as monitored by selected 

parameter values) do not exceed those practices in use during the 

performance tests (that could cause emissions to exceed the levels 

achieved in the compliance demonstration). The alternate 

monitoring practice, used by one commenter, of operating a HCl 

monitor to control the amount of lime injected to the fabric filter 

control system is an acceptable alternative to flux injection rate 

monitoring for controlled sources. This is not an option for 

uncontrolled affected sources or emission units. The final rule has 

been modified to include the option for a HCl monitoring system that 

controls the lime injection feed rate.

The use of bubble monitoring of flux is not a satisfactory 

alternative for SAPU that include both controlled and uncontrolled 

emission units because it is necessary to distinguish between 

consumption in controlled and uncontrolled units. Even for 

controlled units that are served by different control systems, it 

is necessary to monitor rates and consumption of flux in relation 

to rates and consumption of lime so as to monitor the performance 

of the separate control systems. For systems in which all emission 

units are connected to the same control system, bubbled flux 

monitoring across all units is acceptable provided HCl 

concentrations are monitored and demonstrate that the allowable HCl 

emission rate is not exceeded. Extending the flux monitoring 

period to a monthly basis permits daily or cycle-to-cycle variations 

in the relative usage of lime and flux that will not necessarily 

coincide. This will lead to increased emissions as compared to those 

measured during performance tests and thus is not acceptable. 

The final rule has been modified to allow bubbled flux 

monitoring for all emission units connected to the same HCl emissions 

control system if monitoring control system outlet waste gas HCl 

concentrations to demonstrate that the allowable HCl emission rate 

is not exceeded. The final rule retains the requirements for 

monitoring over the operating cycle or period of the performance 

test.
71

4.1.26 Comment: One commenter disagreed with the record 

keeping and compliance certification requirements, stating they are 

unnecessary. In-line refining of molten aluminum for product 

quality purposes without use of reactive flux should not be subject 

to rule. (IV-D-17) Another commenter stated that the requirement 

to identify fluxing agents on a cycle-by-cycle basis is unnecessary 

since in-line fluxers not using reactive fluxes use the same flux 

every day. The certification requirement of 63.1510(m)(2) of the 

proposed rule is sufficient, (m)(1) should be deleted. (IV-D-32) A 

third commenter wanted a monitoring exemption for in-line fluxers 

that do not use reactive flux. (IV-D-31)

Response: The EPA agrees that in-line fluxers that do not use 

reactive flux can be subject to less rigorous record keeping and 

compliance certification requirements than those using reactive 

fluxes. The final rule has been revised to require that 

owner/operators of in-line fluxers that don't use reactive fluxes 

keep a record of the flux materials used (does not have to be on a 

cycle-by-cycle basis) and certify every six months that only those 

materials were processed in the fluxer.

4.1.27 Comment: One commenter suggested adding the word 

sidewell between "Group 1" and "furnace" in 63.1510(n) of the 

proposed rule. (IV-D-32) Another commenter asked for 

clarifications of which requirements in 1510(n), only apply to 

sidewell furnaces. In 1510(n)(1), the latter commenter suggested 

that the operator record whether or not the level of molten metal 

was above the top of the arch and adding a requirement for corrective 

action for the situation if the level is not. (IV-D-20)

Response: At present all the provisions of 63.1510(n) deal 

with sidewell furnaces, so the commenter's suggested addition to 

clarify this is appropriate. The final rule has been changed to 

clarify this point. The rule as proposed does have a corrective 

action requirement in 63.1506(q), however, it may not be clear that 

the operating requirement for metal level in sidewell furnaces is 

covered. The final rule states that maintenance of the metal level 

above the top of the arch is an operating requirement. Failure to 

maintain that level is a violation.

4.1.28 Comment: One commenter interpreted 63.1510(o) of the 

proposed rule to allow the use of COMs as approved alternatives to 

scrap inspection. The requirement in 63.1510(o)(ii) for a 

relationship between parameters and emissions should allow for the 

use of minimum or maximum values below which or above which compliance 

is assured. For example, if flux usage is less than the emission 
72

limit that is sufficient to demonstrate compliance. (IV-D-32) 

Another commenter suggested that one worst case scenario (rather than 

multiple parametric tests) as required in 63.1510(o)(1)(ii) (as well 

as in 63.1505(l) for SAPU's) is adequate to establish operating 

limits for SAPUs. (IV-D-8)

Response: The commenter's interpretation of 63.1510(o) 

relative to Group 1 furnaces without add-on control devices is not 

correct. A COM cannot be used as an alternative to scrap inspection. 

COMs do not provide an indication of D/F, HCl, or Cl2 emissions.

Testing of maximum or worst case flux addition values to 

establish operating limits for SAPU is acceptable. As suggested by 

the commenter, if flux usage is monitored and it is less than the 

emission limit for the affected source or emission unit, this would 

demonstrate compliance.

4.1.29 Comment: One commenter wanted the deadline for 

submittal of the site-specific monitoring plan moved to six months 

before the compliance date, as opposed to six months before the 

performance test.(IV-D-31)

Response: After consideration the EPA agrees that is 

appropriate to change the deadline for submittal of the site-specific 

monitoring plan to at least six months prior to the compliance date. 

That change has been made in the final rule. 

4.1.30 Comment: Several commenters objected to the proposed 

regulatory requirements for scrap inspection programs: 1) 

Several stated that the requirements are too onerous, expensive, 

complex and overly prescriptive, and further, as provided in some 

examples, some provisions are not technically feasible or not 

reasonably met. (IV-D-23, IV-D-22 IV-D-17, IV-D-32, IV-D-18, 

IV-D-20)

2) One commenter stated that the procedures for inspector 

training, certification and program validation and verification will 

place large burden on one of their facilities to maintain on-site 

inspection program. The commenter wanted flexibility of alternate 

inspector training and a less stringent inspection program with 

review and approval by the permit authority. (IV-D-11)

3) Three of the commenters suggested that the broadly stated 

scrap inspection requirements provided in the preamble could be 

acceptable and that approval of site-specific plans by the permitting 

authority would be a more acceptable requirement.

4) Two commenters also stated that scrap should not have to be 

inspected if necessary controls are in place. Inspection is only 

needed for control by work practices or pollution prevention. They 

stated that EPA needs to be clearer as to which sources are covered, 
73

the preamble says all furnaces and the rule says uncontrolled group 

1 furnaces. (IV-D-18, IV-D-20)

Response: The requirement for a scrap inspection program is 

only intended to apply to those facilities that have group 1 furnaces 

without add-on control devices (including those that are part of a 

SAPU). For those facilities that have both add-on controlled and 

uncontrolled group 1 furnaces, the scrap inspection requirements 

would apply only to the materials charged to the uncontrolled units.

As a result of the numerous comments received regarding the 

scrap inspection program elements, the EPA has modified the final 

rule to delete the detailed requirements and adopt the general scrap 

inspection guidance as presented in the proposal preamble. The 

scrap inspection program, if selected by the facility, will remain 

part of the site-specific monitoring plan. The specific inspection 

program elements (which must be consistent with guidance in the 

regulation) will be approvable by the permitting authority as part 

of the site-specific monitoring plan and will be enforceable under 

the permit. 

4.1.31 Comment: One commenter stated that the rule should 

clarify that it is the responsibility of the source to demonstrate 

that scrap inspection program meets intent of rule, including use 

of worst case emission testing, verification sampling of scrap, and 

enforceable contractual arrangements with offsite entities. The 

commenter cited other inspection programs as precedents. (IV-D-9)

Response: See the response above. 

4.1.32 Comment: One commenter supported an alternative scrap 

contamination determination by calculation procedure. (IV-D-11) 

Another commenter supported simplified scrap inspection procedures 

for furnaces dedicated to one type of scrap. (IV-D-8)

Response: In addition to the changes to scrap inspection 

procedures described in the previous responses, the final rule 

contains a calculation method for scrap contamination monitoring for 

group 1 furnaces without add-on control devices that may be 

appropriate for a furnace dedicated to one type of scrap.

4.1.33 Comment: In 63.1510(p) of the proposed rule, one 

commenter wants the term "acceptable scrap" to be defined in the scrap 

inspection program (as scrap that will not cause excess emissions, 

for example). (IV-D-20)

Response: As noted in the responses to previous comments, the 

EPA has substantially revised the requirements for scrap inspection 

programs. The EPA has clarified its intent in the final rule by 

deleting the term "acceptable scrap." which appeared in several 
74

places. The intent in using the term was to describe scrap that meets 

site-specific acceptance criteria under an approved scrap inspection 

program and, that when used, will not cause the affected source to 

exceed the emission limits.

4.1.34 Comment: Section 63.1510(q)(2) of the proposed rule 

dealing with scrap contamination level by calculation, limits 

charges to having the same composition as in the performance test 

which a commenter claimed is impossible. The commenter claimed they 

should be allowed to use a reasonable worst case in the performance 

test and stay below that oil and coating content for ongoing 

compliance. (IV-D-32)

Response: The language in the final rule has been 

modified to explain that "same composition" means oil and coatings 

content equal to or less than that of the scrap used during the 

successful performance test.

4.1.35 Comment: One commenter stated that the scrap 

inspection requirements do not provide for the use of a limited amount 

of coated scrap that could be charged under the emission limit 

provisions for a SAPU. That scrap for an individual furnace might 

have the potential for emissions that exceed an individual furnace 

limit, but be acceptable when the unit is part of the SAPU. (IV-D-11)

Response: Under the scrap inspection requirements and 

site-specific monitoring plan requirements for a SAPU, the testing 

program can be used to establish an emission rate for the furnace 

operating conditions associated with the consumption of a limited 

amount of coated scrap. When an emission unit is operated in such 

a manner, the emission rate associated with that condition would be 

the rate used to compute the 24-hour emissions for that unit as part 

of the SAPU emissions calculations for each pollutant. However, the 

furnace charge cannot be more contaminated than what was used in the 

performance test for that furnace.

4.1.36 Comment: One commenter states that the dates and 

provisions of the Site-Specific Test plan (SST), Secondary Aluminum 

Processing Unit (SAPU) emission plan, Operation, Maintenance and 

Monitoring plan (OM&M) Startup, Shutdown, and Malfunction (SSM) 

plan are too complex and not consistent with each other. The 

commenter requests that EPA combine the SAPU emission plan and OM&M 

into one plan, and fix the dates references. (IV-D-23) Another 

commenter requests the requirements be reviewed and simplified to 

eliminate duplication and reduce the burden to industry. (IV-D-22) 

A third commenter suggests a single compliance plan instead of a site 

specific test plan, a notification of compliance, and an OM&M plan. 
75

(IV-D-8) 

Response: In response to numerous comments related to the 

submission dates for each of the plans and some apparent confusion 

regarding the purpose of each, the final rule has been revised to 

clarify the submission dates and reduce the complexity of the 

requirements. All the dates by which the various plans must be 

submitted are now related to the compliance date which is defined 

in the final rule as not later than 3 years after the promulgation 

date for existing units, or upon startup for new units.

The Startup, Shutdown, and Malfunction (SSM) plan requirements 

are provided in the General Provisions (40CFR 63.6(e)(3) and have 

not been changed. The plan must be developed by the owner/operator 

by the source's compliance date for the relevant standard.

The Operating, Maintenance, and Monitoring (OM&M) plan, which 

includes the site-specific monitoring plan for uncontrolled units, 

if any are present at the facility, must be submitted no later than 

6 months prior to the compliance date or the date by which the facility 

intends to comply, whichever is sooner. Those facilities with a SAPU 

are also required to submit the site-specific SAPU emission plan 

showing the calculation of the SAPU emission limits, explaining how 

SAPU emission limits will be achieved, presenting the test plan for 

performance tests, and other required elements no later than 6 months 

prior to the compliance date or the date by which the facility intends 

to comply, whichever is sooner.

 4.1.37 Comment: One commenter is concerned with the 

stipulations of 63.1505(k) that require complying with all 

requirements of the SAPU emission plan plus all the requirements for 

each individual emission unit in the SAPU. The commenter wants to 

negotiate with the permitting agency for collection of needed data 

for the site-specific monitoring plan and the SAPU emissions plan 

to demonstrate compliance. The commenter does not want to collect 

monitoring data for each and every emission unit within the SAPU, 

especially for multiple units connected to a common control device. 

The commenter suggests alternate language for 63.1505(k)(5) that 

requires compliance with the requirements of an approved 

site-specific SAPU emission plan and, if applicable, a site-specific 

monitoring plan (under the OM&M plan) without having to do it for 

each individual emission unit. (IV-D-32)

Response: To simplify the compliance process, the requirement 

for a separate site-specific emissions plan contained in the proposed 

rule at 63.1505(k) has been removed from the final rule. The 

elements of data and information required for submittal to the 

permitting authority in this plan under the proposed rule have been 

incorporated into the OM&M plan in the final rule as described at 
76

63.1510(s). Across the industry affected by these rules there will 

be significant variations between facilities in terms of 

combinations of controlled and uncontrolled emission units and 

control systems. In view of this fact, the commenter's request to 

negotiate with the permitting agency for collection of data for the 

site-specific monitoring plan (and previous emission plan data) 

under the OM&M plan is reasonable and allowed under the final rule. 

The Agency has revised the final rule and provided some additional 

guidance to assist the owner/operator and permitting authorities in 

this matter.

For controlled and uncontrolled emission units it is necessary 

to monitor the individual units with respect to charge weight and 

flux consumption. The charge weight is essential to the calculation 

of allowable emissions for a SAPU, and the flux usage must be 

maintained at or below the values at which the individual units were 

tested when operating at the defined worst case conditions during 

the compliance test. The need for these data is present even if 

emission units are connected to a common control device. Just as 

for a system that controls an individual affected source or emission 

unit, the lime injection in a system that provides cocontrol must 

be coordinated with emission unit operations to maintain sufficient 

lime availability to remove HCl, Cl2, and HF emissions. Solid 

reactive flux usage must also be considered in regard to maintaining 

adequate lime availability.

4.1.38 Comment: One commenter wanted clarification that SSM 

plans are not part of the operating permit. They requested a 30 day 

deadline for plan approval by EPA, with unreviewed plans considered 

approved by default. (IV-D-8)

Response: The General Provisions (40CFR 63.6(e)(3) direct that 

the SSM plan be incorporated by reference into the source's Title 

V permit. With regard to the issue of approval within 30 days, 

owner/operators of potentially affected existing sources will have 

up to 3 years from the promulgation date during which they can prepare 

and submit the SSM plan for approval. They need to work with the 

permitting authority to develop a workable plan sufficiently far in 

advance that approval within 30 days is not necessary. Unreviewed 

plans cannot be considered approved by default.

4.1.39 Comment: Two commenters stated that the SSM plan 

should apply only to units with control devices as is the case in 

the Printing and Publishing MACT. (IV-D-23, IV-D-8)

Response: While the add-on air pollution control devices play 

the primary role in emission control, variation in the process 

operations generating the waste gas stream and pollutants affect the 
77

emissions as well. Further, these standards anticipate the presence 

of emission units using pollution prevention approaches as part of 

secondary aluminum processing units in many facilities. These 

emission units and the associated work practices and pollution 

prevention measures are the means by which emissions are limited in 

the SAPU. For these reasons, and consistent with the General 

Provisions, all affected sources and emission units must be included 

in the SSM plan.

4.1.40 Comment: One commenter suggested that EPA allow 

facilities to establish alternative site-specific OM&M plans subject 

to permit authority review and approval. These alternative plans 

would include monitoring provisions different from those in the 

proposed rule, and reflect changes needed to deal with difficulties 

specific facilities would encounter in adopting the EPA proposed 

monitoring provisions. (IV-D-11)

Response: All OM&M plans submitted will be site-specific by 

definition. As noted in comment responses above, changes have been 

made in the final rule to provide more flexibility in monitoring the 

quantity and accuracy of feed/charge weight, flux usage, lime 

addition, and scrap inspection. If an owner/operator wants to use 

alternative monitoring schemes different than those described as 

acceptable in the final rule, the procedure to gain approval is to 

submit a request and obtain approval of the alternative scheme from 

the Administrator. The final rule provides the requirements for 

obtaining approval in 63.1510(w).

4.1.41 Comment: Two commenters did not want the OM&M and SAPU 

emissions plan incorporated in Title V permit because it will make 

all operating, maintenance, and monitoring procedures enforceable 

permit conditions. The commenters stated that it will also be too 

difficult to make minor changes to their operations without amending 

the permit which could cause delays for weeks or months. (IV-D-23, 

IV-D-8) Another commenter also disagreed with the requirement to 

have the OM&M plan be part of the Part 70 and 71 permit. They stated 

that the site-specific monitoring plan should be developed for and 

approved by the applicable permitting authority. (IV-D-17)

Response: The proposed rule required the OM&M plan to be 

submitted to the applicable permitting authority as part of the 

application for a Part 70 or 71 permit. Based on the comments 

received and a further review of the proposed requirements, the EPA 

is clarifying the requirements for the OM&M plan. It was not EPA's 

intention to have the OM&M plan itself be incorporated into the 

permit, such that it would be necessary to reopen the permit if 

changes to the OM&M plan are desired. The OM&M plan is to be 
78

incorporated into the permit by reference so that it is not necessary 

to revise the permit when a change in the OM&M plan is desired. For 

those facilities that already have a Title V permit when the final 

rule is promulgated, the OM&M plan will be incorporated by reference.

The OM&M plan requirements become enforceable under the permit upon 

approval by the permitting authority.

If an owner/operator wants to revise the ranges or limits 

established for the operating standards, they must:

(1) Submit a request to and obtain approval from the permitting 

authority to conduct a performance test to revise the operating 

requirement ranges or limits.

(2) After receiving approval from the permitting authority, 

conduct a performance test to demonstrate that compliance with the 

emissions standards can be achieved at the revised operating 

conditions.

(3) Submit the performance test results and the revised OM&M 

plan to the permitting authority for approval.

(4) Pending Administrator approval of the revised OM&M plan, 

the owner/operator must comply with the provisions of the approved 

plan.

If the owner/operator is revising an aspect of the plan that 

does not require an additional performance test, for example, 

maintenance procedures, they must submit only a final plan to the 

permitting authority for approval. Pending the Administrator's 

approval of the changes, they must comply with the provisions of their 

approved plan.

4.1.42 Comment: Two commenters agreed with EPA and support 

no monitoring or performance testing provisions for group 2 furnaces. 

(IV-D-23, IV-D-32) One of the commenters urged EPA to include 

external preconsumer runaround scrap in the definition of clean 

charge. The commenter claimed this material, often returned from 

their customers who do not have melting capability, is as clean and 

predictable as internal runaround. (IV-D-32)

Response: The EPA acknowledges the support for the decision 

not to require monitoring and performance testing for group 2 

furnaces. For a discussion of EPA’s consideration of a revision to 

the definition of “clean charge,” see the response to comment 2.1.

4.1.43 Comment: Identification of all charge materials in 

63.1510(r)(1) of the proposed rule is unnecessary according to two 

commenters. Some group 2 melters are used in similar service day 

after day, and cycle after cycle. Only monitoring sufficient to 

supply the certification in 63.1510(r)2 of the proposed rule should 

be required. (IV-D-32, IV-D-8)
79

Response: The EPA agrees that in such situations it is not 

necessary to keep cycle-by-cycle records for Group 2 furnaces. The 

owner/operator must record all the materials charged to the furnace 

that make it a Group 2 furnace. Then, the six-month certification 

of compliance must contain the information specified in 

63.1516(b)(2)(v) of the proposed rule and certify that only the 

materials they recorded as charged to the furnace were used during 

that 6-month period.

4.1.44 Comment: Another commenter opposed the requirement to 

record charge and flux materials, unless those materials deviate from 

the OM&M plan.(IV-D-31)

Response: Records of charge and flux materials used in the SAPU 

are necessary to demonstrate continuous compliance with the emission 

and operating limits. Such monitoring observations that show 

deviations from the ranges or limits established during the initial 

compliance or performance test are violations of the standard unless 

caused by events covered by the SSM plan. 

4.1.45 Comment: In 63.1510(s)(2) of the proposed rule 

referring to calculation of 3-day, 24-hour rolling average 

emissions, one commenter stated the words "most recent" should be 

added when referring to the performance test because tests are 

conducted every 5 years. (IV-D-20)

Response: The commenter was referring to using the results from 

the most recent performance test in the calculations to monitor 

compliance. However, the emission factors established for each 

affected source or emission unit that is part of a SAPU can only be 

changed by revising the site-specific OM&M plan (the portion required 

by 63.1510(s)) per the procedures described in a comment response 

above under Title V permit comments. The most recent performance 

test may or may not be the basis for the currently approved 

site-specific OM&M plan incorporated in the permit. Only if the most 

recent performance test is the basis for the approved OM&M plan can 

those results be used to calculate the 3-day, 24-hour rolling average 

emissions under 63.1510(t).

4.1.46 Comment: Another commenter wants the instructions for 

calculating and recording the average emissions based on up to a 

30-day average and a 30-day SAPU compliance period. (IV-D-31)

Response: Data used to establish the emission limits and 

operating requirements were based on source tests conducted over 

relatively short durations. The test periods required for initial 

compliance determinations are based on full process operating cycles 

or 24-hour periods, whichever is less. For this reason, the final 
80

rule retains the requirement to demonstrate compliance on a 3-day 

24 hour rolling average basis. Sufficient data to establish lower 

30-day emission limits and monitoring parameters are not available.

4.1.47 Comment: Several commenters wanted an alternative to, 

or believe that EPA did not intend to require, multiple testing over 

different furnace operating (range of charge/flux) conditions. One 

commenter wanted to test under worst case scenario rather than across 

range of variables (uncontrolled units) as required in 63.1510(o) 

and 63.1505(l) of the proposed rule. The commenter gave examples 

of situations where it would be appropriate and estimates of 

associated cost savings. The commenter suggested language allowing 

a permitting authority to approve a test plan if judged to contain 

sufficient provisions to ensure compliance. (IV-D-23) Another 

commenter wanted an alternative to correlations between measured 

emissions and parameters to be monitored. For example a minimum or 

maximum parameter value under which emissions may be less than the 

limit, i.e., flux usage is less than the limit therefore the limit 

will not be exceeded. (IV-D-32) Several other commenters stated that 

a defined worst case condition test will often be adequate to set 

upper limits on flux use and charge material. Such an approach 

should be allowed if approved by the permitting authority. (IV-D-17, 

IV-D-22, IV-D-11)

Response: The purpose of requiring tests over a range of 

different furnace operating conditions is to show that the selected 

monitoring parameters are valid indicators of relative emission 

levels over the range of furnace operating conditions for 

uncontrolled furnaces. Testing at maximum or worst case charge/flux 

addition values to establish operating limits for emission units in 

a SAPU is acceptable provided that the owner/operator can show the 

tested cases produce maximum emissions for all regulated pollutants. 

However, the measured value of emissions for that maximum case is 

the level of emissions that must be used in the 24-hour average 

emission calculations for that unit within a SAPU. Also, to be in 

compliance after the compliance date, the flux rate used in the each 

emission unit must be equal to or less than the amount used during 

the maximum or worst case test, and the charge materials must be of 

equal or lower oils and coatings content than the charge materials 

used during the maximum or worst case test.

There are some cases in which it may not be possible to establish 

that a particular test represents a maximum or worst case scenario. 

For example, it may not possible to show that a particular combination 

of oil and coating scrap contamination is worse than another 

combination without actually performing a test under both 

conditions. 
81

As suggested by the commenter, if flux usage is monitored and 

it is less than the emission limit for the affected source or emission 

unit, this would demonstrate compliance with the HCl limit.

4.1.48 Comment: A commenter believes that the language of the 

proposed rule requires all operators of secondary aluminum 

processing units to develop a correlation between emissions and 

monitored parameters, and that it is not clear that this correlation 

is only required for uncontrolled Group 1 furnaces. The commenter 

requests explicit language that parameter/emission correlations are 

necessary only when used to demonstrate compliance with the standard. 

(IV-D-28)

Response: The proposed rule at 63.1510(o)(1)(ii) required 

that the owner/operator of a SAPU show a relationship between 

emissions and monitoring parameters over the entire range of charge 

and flux materials processed in the furnace (emission unit). Also, 

the proposed rule at 63.1505(l)(2)(vii) required that the 

site-specific secondary aluminum processing unit emissions plan 

include a correlation of measured emissions with the selected process 

or operating parameter to be monitored, as part of the application 

for an operating permit. The final rule has been revised to 

eliminate the requirement for such a correlation. The Agency has 

concluded that it will be sufficient to identify maximum or worst 

case charge and flux conditions under which tests are performed to 

establish the monitoring parameter values or ranges. As noted above 

in a previous comment response, in some situations it may be necessary 

to perform tests at several conditions to establish which of the 

conditions are representative of maximum or worst case conditions 

for an emission unit. 

4.1.49 Comment: One commenter supported a scaled down 

monitoring program with reduced monitoring requirements for those 

units operating at half (for example) the federal emission limitation 

to provide an incentive for applying controls and operating practices 

that exceed the MACT floor. (IV-D-22)

Response: Measurements that demonstrate operation at low 

emission rates are short-term indicators of performance. Process 

operations vary with time and cannot be relied upon to remain 

constant. For this reason the EPA has retained the basic monitoring 

requirements for all units regardless of the emission levels achieved 

in relation to the emission limits.

4.1.50 Comment: One commenter requested clarification of 

what is meant by "relative accuracy" in Section 63.1510 of the 

proposed rule. When used in conjunction with continuous monitoring 
82

systems there are usually set protocols giving procedures and 

equations to determine relative accuracy. (IV-D-20)

Response: This comment refers to requirements in the proposed 

rule for temperature monitoring devices at fabric filter inlets. 

That section has been revised in the final rule to delete the relative 

accuracy requirement. The language has been revised to only require 

that 1) the recorder response range must include zero and 1.5 times 

the average temperature established according to the requirements 

in §63.1512(n) for affected sources or emission units using fabric 

filters for D/F or HCl control, and 2) the reference method must be 

a National Institute of Standards and Technology calibrated 

reference thermocouple-potentiometer system or alternate reference, 

subject to approval by the Administrator.

4.2 Performance Testing and Compliance

4.2.1 Comment: Commenters wanted the compliance date to be 

3 years after promulgation rather than "on or after the date of the 

initial performance test." (IV-D-8, IV-D-22, IV-D-23) They argued 

that:

1) Carrying out performance tests prior to the end of 3 years 

is essential to completing the monumental job; but they do not like 

having to comply "on and after the date of the initial performance 

test" which could be the emission test program for the SAPU.

2) The submittal deadlines for the OM&M plan, the SAPU emission 

plan, and the site-specific test plan are inconsistent with each 

other; they wanted EPA to remove all the interim compliance 

requirements to give the necessary flexibility to evaluate and agree 

with the permitting agency on compliance requirements before the 

3-year deadline.

Response: A facility must be in compliance on and after the 

date of the initial performance test. The date of that initial 

performance test, for existing sources, may be up to 3 years after 

the promulgation date of the standard. For existing SAPUs, the 

initial performance test is considered to be the date of approval 

of the OM&M plan by the permitting authority. 

In response to the comments regarding the inconsistent plan 

requirements and dates for submittal, the EPA has revised and 

clarified those requirements. The final rule requires the 

owner/operator of a SAPU to perform tests that will define the 

operating modes of the controlled and uncontrolled emission units 

within the SAPU, and to define which parameters to monitor to 

demonstrate continuous compliance. These same tests can be used to 

measure the emission rates from the affected sources and emission 

units for performance test purposes. A site-specific test plan for 
83

this program must be submitted to the permitting authority for review 

and approval before the tests are conducted. The plan must identify 

the parameters to be monitored during the tests, the test methods 

to be used, the units to be tested, and planned operating modes for 

each unit during the tests. After the test plan has been approved 

by the permitting authority, the owner/operator is required to notify 

the Administrator of the test dates.

The results from this test program, including the emission rates 

measured, values of parameters monitored, monitoring parameters 

selected by the owner/operator for compliance demonstration, and 

values of the parameters to be used as operating limits must be 

submitted to the permitting authority for review and approval. As 

a result of the review, the permitting authority may request changes 

to selected monitoring parameters or values of the parameters used 

for compliance demonstration if it is determined the parameters or 

values do not provide an adequate means of demonstrating continuous 

compliance. When all of these elements are approved by the 

permitting authority, the owner/operator prepares an OM&M plan using 

the approved monitoring scheme and submits the OM&M plan to the 

permitting authority for approval. The compliance date is the 

approval date of the OM&M plan. The approved OM&M plan will be 

included by reference in the operating permit.

The latest date for an existing facility to achieve compliance 

is 3 years from the date the standard is promulgated. The OM&M plan 

must be submitted to the permitting authority for approval no later 

than 6 months before the planned compliance date. Given these 

conditions and lead times for preparing plans and conducting tests, 

it is clear that owner/operators must act expeditiously to develop 

test plans and execute the test programs. 

Facilities that choose to comply by demonstrating that each 

emission unit in the SAPU meets the emission limit for that unit, 

and by monitoring the parameters as designated in the rule for each 

emission unit and control device, are also required to develop a test 

plan and notify the permitting authority of the test date(s).

4.2.2 Comment: Several commenters wanted EPA to allow 

testing one representative unit from a group of similar sources, that 

is one unit to represent similar furnaces or in-line fluxers, instead 

of having to test every emission unit. One of the commenters stated 

that this practice should be allowed for either controlled or 

uncontrolled units. Several commenters claim this approach is 

widely used under existing State permits and has been used by EPA 

in other NESHAPs. Commenters claimed that it would significantly 

reduce costs, provide flexibility, and provide more cost-effective 

test programs. (IV-D-9, IV-D-17, IV-D-22, IV-D-23, IV-D-32, IV-D-33, 
84

IV-D-35)

Response: Based on the comments received, the EPA is modifying 

the testing requirements to allow representative or similar 

uncontrolled emission units that use like charge and flux materials 

to be tested, instead of requiring each unit to be tested. Testing 

of representative or similar units may be used provided approval is 

obtained from the applicable permitting authority. The 

representative unit selected for testing must be subject to the same 

work practices and be of the same design as those emission units it 

is representing for test purposes. The representative unit must be 

tested under worst case conditions. It is up to the owner/operator 

to define the worst case scenario(s) for review and approval by the 

permitting authority. At least one of each different style unit must 

be tested. Each add-on control device controlling emissions from 

an affected source or emission unit must be tested.

4.2.3 Comment: One commenter suggested exempting clean 

charge furnaces and in-line fluxers from the HCl performance test 

if chlorine usage is less that emission limit. (IV-D-8) Another 

commenter requested an alternative to performance testing to show 

that chlorine usage is less than the emission limit and specifically 

requested this as an alternative for uncontrolled in-line fluxers. 

(IV-D-31). Two other commenters stated that Part II of 

Pharmaceutical Product NESHAP permitted owners to use calculational 

methodologies to determine emission rates for individual process 

vents. (IV-D-22, IV-D-35)

Response: The EPA agrees that it is reasonable to provide 

alternate procedures for owner/operators to demonstrate that HCl 

emissions are less than the emission limit for clean charge furnaces 

and uncontrolled in-line fluxers. If the flux (weight equivalent 

as HCl) usage rate is less than the emission limit for an affected 

source this is a sufficient demonstration that the source is in 

compliance with the standard. The weight equivalent HCl must be 

determined for both gaseous and solid reactive fluxes used during 

the furnace cycle or performance test period. 

4.2.4 Comment: Submitting the site-specific test plan in 

accordance with general provision 63.7 would require the plan going 

to the "Administrator." The commenter stated that they believe that 

it's EPA's intent for the plan to go to the applicable regulatory 

authority. (IV-D-17) Another commenter stated that the proposed 

requirement to submit performance test plans for approval goes beyond 

the General Provisions. The commenter argued that this requirement 

will greatly increase the burden to permitting agencies and may 

interfere with schedules needed to complete tests before compliance 
85

deadline. (IV-D-32)

Response: The general provisions state that before conducting 

a performance test the owner/operator of the affected source must 

develop and, if requested by the Administrator, submit the plan for 

approval. Due to the complexity of testing for demonstration of SAPU 

compliance (facilities with combinations of controlled and 

uncontrolled emission units, multiple emission units controlled 

through common control devices, etc.) the Agency has decided that 

the test plans must be submitted for approval. The General 

Provisions at 63.2 define Administrator to mean the Administrator 

of the U.S. Environmental Protection Agency, or his or her authorized 

representative (e.g., the State that has delegated authority to 

implement the provisions of this part). In the case of authorized 

states, the plan would go to the permitting authority for approval.

Facilities having Group 1 furnaces without add-on control 

devices must develop test data to support their OM&M plan. 

Specifically they are required to develop a site-specific monitoring 

plan as part of the OM&M plan based in part on test data. If 

facilities wish to use test data collected during development of the 

SAPU OM&M plan later as a compliance demonstration, a test plan should 

be prepared for approval prior to the OM&M plan testing activity. 

The benefit to owner/operators in submitting the plan for approval 

is that they may avoid the necessity of conducting two separate sets 

of tests, one for OM&M development and one for compliance 

demonstration. 

4.2.5 Comment: One commenter stated that the requirement to 

operate all affected sources connected to a common stack during tests 

of that common stack is not feasible and not necessary. The 

commenter claimed that even at the highest production rate, some 

facilities may not operate all affected sources simultaneously. The 

commenter supports the EPA decision to allow a single test to 

characterize emissions from multiple sources ducted to a common 

stack. Further, the commenter requested that the regulatory 

paragraph should be expanded to affirm that new emissions units may 

be ducted to existing control systems, if capacity is available or 

can be expanded to accommodate the new source. (IV-D-32)

Response: The EPA understands that it may not be feasible to 

operate all emission units connected to a common stack simultaneously 

during a performance test. The intent has been clarified in the 

final rule by stating that the performance test must be conducted 

at a maximum production rate scenario, i.e. the number of operating 

emission units or affected sources connected to the common control 

device or stack must represent a maximum or highest emission rate 

condition for the commonly controlled units or sources.
86

For the reasons stated in the response to comment 1.6 in this 

document new emission units may not be cocontrolled with existing 

units.

4.2.6 Comment: One commenter opposed the mandatory retesting 

every 5 years and claimed that alternative evidence ensuring 

compliance should suffice. That is, if the required controls are 

in place, the floor limits are literally guaranteed according to the 

preamble of the proposed rule. (IV-D-10)

Response: In general, the presence of required controls is not 

sufficient to ensure compliance. Proper operation and maintenance 

of the control systems are also necessary elements to ensure 

compliance. Over a period of years changes may also occur in process 

operations that affect emissions and control device performance. 

For these reasons the requirement to retest every 5 years is being 

retained in the final rule.

4.2.7 Comment: One commenter stated that it is not clear what 

is meant in 1511(e) of the proposed rule by "at the time of permit 

renewal." If the source test results are meant to be used in the 

renewal application, the testing needs to happen far in advance. 

Also the commenter observed that the permit renewal dates may be more 

than 5 years apart in some cases. (IV-D-20)

Response: It is the EPA's intent that each new or existing 

affected source or emission unit be retested every 5th year after 

the initial performance test. Given that this may not coincide with 

permit renewal, the final rule has been modified by deleting that 

phrase from the retesting requirement.

4.2.8 Comment: One commenter supported the choice of 

performance test methods designated by EPA. (IV-D-23)

Response: The EPA acknowledges support of the test method 

selection.

4.2.9 Comment: One commenter requested additional language 

in the regulation stating that if the format of the emission limit 

(units, lb/ton) is the same for all units (units ducted to a common 

control device), compliance is demonstrated if the combined emission 

limit for all units is not exceeded. (IV-D-23) 

Response: For units that are all part of the same SAPU no 

additional language is necessary, emission limits are all written 

in the same format (e.g. lbs/ton). Compliance is demonstrated if 

the combined emission limit for all units is not exceeded. For other 

existing sources, such as delacquering kilns and furnaces going to 

a common fabric filter, a case-by-case compliance demonstration is 
87

required with the permitting authority providing approval of the test 

plan before the tests are conducted.

4.2.10 Comment: Section 63.1511(f)(3) of the proposed rule, 

regarding establishment of operating and monitoring parameter 

values, that existing data may be used if, among other conditions, 

no design or work practice changes have been made since the time the 

previous data were reported in order to make the previous data 

acceptable for compliance demonstration. Two commenters observed 

that not all work practice or design changes will affect emissions 

or the operating parameters. The commenters requested a 

clarification that only design and work practices affecting 

emissions may not have changed since the previous report in order 

for the data to be an acceptable demonstration. (IV-D-17, IV-D-23)

Response: The proposed provision required the owner/operator 

to certify that no changes in work practice or design have been made 

since the previous data were obtained. It also stated that the 

conditions must be met to the satisfaction of the permitting 

authority. If changes have been made and the owner/operator 

believes the changes have no bearing on emissions, the owner/operator 

can include an explanation for review and consideration by the 

permitting authority. The permitting authority would determine 

whether to accept the previous data after consideration of whether 

all the necessary conditions have been met. The final rule retains 

the provision as proposed in 63.1511(g).

4.2.11 Comment: One commenter stated that sources should be 

able to use test results obtained prior to the compliance deadline 

as a demonstration of compliance. (IV-D-28) 

Response: Test results obtained with the methods required for 

performance testing in the final rule, in coordination with 

development of the required operating and monitoring parameter 

values or ranges as required in the final rule, may be used as a 

demonstration of compliance at the compliance deadline, provided 

that all the conditions of 63.1511(g) cited in the previous comment 

have been met. Submittal of all the necessary supporting 

information and data would be part of the OM&M plan preparation, 

review, and approval process with the permitting authority. 

4.2.12 Comment: One commenter requested that different 

affected sources connected to a common control device be permitted 

the flexibility to allow consistent monitoring and compliance 

periods, for example a delacquering kiln and SAPU furnaces. (IV-D-23)

Response: Although the example provided by the commenter is 

a case in which the emission limit formats are the same for different 
88

affected sources, the pollutants regulated, and the monitoring and 

compliance periods will be different. The difference in the 

monitoring and compliance period for different affected sources can 

be significant. For example SAPU compliance is determined on the 

basis of 3-day, 24-hour rolling average emissions and delacquering 

kilns are based on the average of three 3-hour test runs. 

Furthermore, there is no legal construct under the CAA that provides 

for emissions from two different affected sources to be averaged. 

The final rule requires that compliance for different affected 

sources must be determined separately. 

4.2.13 Comment: One commenter suggested improved wording for 

1511(b)(4) of the proposed rule as follows: "Where multiple affected 

sources or emission units are exhausted through a common stack, 

pollutant sampling for each run must be conducted over a period of 

time during which all affected sources or emission units complete 

at least one entire process operating cycle or for 24 hours, whichever 

was shorter. (IV-D-20)

Response: The EPA has adopted the suggested wording change in 

the final rule.

4.2.14 Comment: One commenter stated that the wording in 

Section 63.1512(j) of the proposed rule presumes there are always 

control devices present on emission units within the SAPU because 

testing is required at the outlet to the control device. However, 

some emission units may not be controlled, so the requirements will 

need to be reworded. (IV-D-20)

Response: The commenter correctly noted that a wording change 

is necessary to include testing for uncontrolled emission units. 

The final rule has been modified to incorporate the language changes 

at 63.1512(e).

4.2.15 Comment: One commenter stated that testing, 

especially for area sources, is needlessly burdensome and expensive. 

According to the commenter, the EPA should provide an option to use 

reliable emission factors. The owner should not be required to test 

at highest production level if they can show it would never or could 

never be operated at such. There should be something like synthetic 

minor status available. The commenter claimed that having to submit 

results of "any" test will discourage owners from exploring 

alternative operating scenarios; owners should have the choice to 

test actual emissions and control HAPs based on feed material 

certification instead of controlling PM. (IV-D-27)

Response: Area sources mentioned by the commenter are only 

being regulated for D/F emissions from the processes for which D/F 
89

emission limits have been established. Therefore area sources are 

not required to control PM under this rule. The EPA recognizes that 

testing of sources to determine D/F emissions may be relatively 

costly in comparison to the cost of some process equipment subject 

to the rule, and amount of material processed in the affected source, 

i.e. sweat furnaces. There are not reliable emission factors 

available for estimation of D/F emissions for regulatory purposes.

As a result of comments received, and after further 

consideration, the EPA has determined to revise the standard for 

sweat furnaces. The final rule provides that a sweat furnace 

equipped with an afterburner with 2 second residence time and with 

a design temperature of at least 1600 F is not required to conduct 

a performance test to demonstrate compliance with the D/F emission 

limit. The D/F emission limits proposed are being retained in the 

final rule. Owner/operators of sweat furnaces located at facilities 

which are area sources can elect to demonstrate compliance with the 

D/F emission limits for those existing afterburners that may not meet 

the equipment specifications through a one-time test. 

4.3 Notifications, Reports, and Records

4.3.1 Comment: One commenter noted that the compliance 

certification requirement in Section 63.1516(c) of the proposed rule 

limits the information required in annual compliance certifications. 

The commenter suggested making the language consistent with 40 CFR 

70.6(5)(iii) which is included in their comment. The suggested 

language is much broader than that of the proposed rule. (IV-D-20)

Response: The EPA did not intend to limit the information that 

could be required in annual compliance certifications by the 

permitting authority. The wording has been changed in the final rule 

to state that compliance certification must "at least" contain the 

items listed.

4.3.2 Comment: One commenter requested the requirement to 

develop a Startup, Shutdown, and Malfunction (SSM) plan to apply only 

to controlled sources. The same commenter wanted to eliminate the 

requirement to certify the use of only "non-HAP containing, non-HAP 

generating flux gases" from the reporting provision of Section 

63.1517(b)(2)(vi) of the proposed rule for in-line fluxer using no 

reactive flux, and certify only "non-reactive flux gases" are used. 

(IV-D-31)

Response: While the add-on air pollution control devices play 

the primary role in emission control, variation in the process 

operations generating the waste gas stream and pollutants affect the 

emissions as well. Further, these standards anticipate the presence 
90

of emission units using pollution prevention approaches rather than 

add-on controls as part of secondary aluminum processing units in 

many facilities. These emission units and the associated work 

practices and pollution prevention measures are the means by which 

emissions are limited in the SAPU. For these reasons, and consistent 

with the General Provisions, all affected sources and emission units 

must be included in the SSM plan.

The certification requirement for “in-line fluxer using no 

reactive flux” has been retained in the final rule as it was proposed. 

This provision is necessary for consistency with the requirements 

for group 2 furnaces. Both emission units have no emission limits 

and are therefore subject to this more stringent certification 

statement. 

4.3.3 Comment: One commenter stated that the requirement for 

the quality improvement plan (QIP) in 63.1515(b)(11) of the proposed 

rule should be deleted because this is the only place in the rule 

it is mentioned. (IV-D-17) Another commenter asked for a 

clarification stating that if the QIP in 1515(b)(11) of the proposed 

rule refers to the QIP of 40 CFR 64, EPA should clearly state that. 

(IV-D-20)

Response: This reference to the Quality Improvement Plan was 

inadvertently left in the proposed rule when published; it was not 

intended to be a requirement and has been removed.

4.4 Applicability of General Provisions

4.4.1 Comment: One commenter provided a table with comments 

supporting or opposing, and noting no or neutral comments, on the 

applicability of each of the General Provisions requirements shown 

in Appendix A to Subpart RRR. (IV-D-23)

Response: The EPA has reviewed applicability of the general 

provisions and, except as noted in Appendix A to the final rule, all 

of the general provisions apply to this subpart.

5. Impacts

5.1 Comment: Several commenters (IV-D-12, IV-D-14, IV-D-15, 

IV-D-16, IV-D-18, IV-D-19, IV-D-20, IV-D-21, IV-D-23, IV-D-27, 

IV-D-30, IV-D-32) disagreed with the results of EPA's regulatory 

impact analysis and believed that EPA underestimated the cost of the 

rule. The commenters identified the following as deficiencies in 

the impact analysis: 

1) The EPA underestimated the number of area sources that would 

be impacted as a result of the area source D/F standard. In 
91

particular, owners or operators of sweat furnaces, die casting 

facilities, foundries, and extruders were identified as potentially 

affected area sources that were either excluded or not adequately 

accounted for in the analysis. Furthermore, the commenters claimed 

that the proposed monitoring, recordkeeping, and reporting, and 

title V permit requirements would impose a significant burden on area 

sources.

2) The EPA understated the number of small businesses that 

would be affected by the rule and, as a result, EPA's analysis of 

impacts on small entities was not adequate. According to several 

of the commenters, the small business impacts analysis 

underestimated small business impacts because it did not accurately 

account for sweat furnaces, die casting facilities, foundries, and 

extrusion facilities, many of which are small businesses and would 

be subject to the rule. The commenters also claimed that the 

proposed monitoring, recordkeeping, reporting, and title V permit 

requirements would impose significant burdens on these small 

businesses. They argued that the rule would have a significant 

impact on a substantial number of small entities and that EPA must, 

therefore, perform a regulatory flexibility analysis as required by 

the Regulatory Flexibility Act.

3) Commenters took issue with the methods and assumptions used 

by EPA to estimate the costs and economic impacts of the rule, 

including failure to adequately account for the large number of 

affected area sources, title V permitting costs for area sources, 

and underestimating performance test costs due to the assumption of 

shared stacks. As a result, the commenters state that EPA's costs 

and economic impact estimates are too low. They argue that the 

annualized cost of the rule exceeds $100 million and is, therefore, 

a significant regulatory action under Executive Order 12866.

Response: Based on the numerous comments received regarding 

the regulatory impact analysis, the EPA has reviewed, revised, 

updated, and refined the analysis to address commenters' points:

1) With regard to commenters' first point, for the proposed 

rule, the EPA used the information available on area sources of D/F 

emissions and requested additional information on the number of area 

sources, levels of emissions from these sources, the level of control 

currently employed, and the number of area sources that are also small 

businesses. In response to the comments on the proposed rule, and 

using the information provided by commenters on sweat furnaces, die 

casting facilities and foundries, EPA has reassessed the cost of the 

rule on area sources (see Docket item IV-B-4). In addition, EPA has 

clarified and, in some cases, revised the proposed rule to address 

commenter concerns that the proposed rule will be overly burdensome 

for area sources. These changes include clarifications or revisions 
92

in the applicability of the rule, the performance testing 

requirements, the scrap inspection program, and giving the State 

permitting authorities the discretion to defer the requirements for 

a title V permit for area sources. On the basis of the information 

submitted to EPA during the public comment period and changes made 

to the proposed rule that narrow the applicability to facilities that 

are area sources (primarily aluminum extruders, die casters, and 

foundries), the EPA believes the number of those facilities subject 

to the rule to be small. 

2) Regarding the commenters' second point, after reviewing the 

comments on the small business impacts of the proposed rule and using 

the information on sweat furnaces, die casting facilities, and 

foundries provided by commenters, EPA has refined its small business 

impacts analysis (see Docket item IV-B-6). The analysis shows that 

the final rule will not have a significant impact on a substantial 

number of small businesses; therefore, no regulatory flexibility 

analysis is required. The small business impact analysis shows that 

the impact to small businesses operating sweat furnaces, and to small 

firms in the aluminum die casting and aluminum foundry industries 

is minimal.

3) Regarding the commenters' third point, EPA considered the 

comments objecting to the costing methods and assumptions it used 

to estimate the impacts of the proposed rule. The EPA has reexamined 

its cost estimating procedures and believes that overall it has 

overstated the cost of the proposed rule. However, in view of the 

changes in the proposed rule, and to incorporate revisions in the 

estimated number of affected area sources, EPA has updated its 

estimate of the cost of the rule (see Docket item IV-B-4 and IV-B-5). 

The revised cost of the rule is below the $100 million per year 

threshold, therefore, the rule is not a significant regulatory action 

as defined under Executive Order 12866.

5.2 Comment: One commenter claimed that under the proposed 

rule one of their facilities would be unable to use their existing 

monitoring procedures, which were approved by EPA and the State of 

Washington, e.g., data from existing COMs under existing SIP 

procedures, single upstream chlorine feed monitoring, and an 

existing weigh feeder for trona injection (more accurate and reliable 

than proposed EPA visual inspection). The cost of the facility's 

existing monitoring systems exceeds those monitoring costs estimated 

by EPA for similar model plants. This commenter also claims that 

EPA substantially underestimated costs for installing and operating 

monitoring systems by comparing costs for their facility to EPA Model 

Plant 6. (IV-D-32)

Response: In considering the comment, EPA notes that the 
93

monitoring and operating requirements of the rule have been revised 

to be less prescriptive and provide greater flexibility for affected 

sources. The final rule has been revised to provide for approval of 

site-specific monitoring and operating alternatives, within EPA 

guidelines, by the permitting authority. However, should an 

owner/operator find that the provisions in the final rule for getting 

approval of site-specific plans do not cover a particular situation 

or fail to meet their needs, the General Provisions provide for the 

use of alternatives to monitoring requirements or procedures upon 

approval by the Administrator. EPA believes that these revisions 

to the rule provide industry with the flexibility necessary to comply 

with the monitoring requirements efficiently and at a reasonable 

cost.

5.3 Comment: One commenter stated that because they never have 

been required to measure D/F emissions, they may have to spend 

$100,000 per plant site just to establish what their emissions are 

and that the additional cost of controls is unknown until they 

establish their baseline emissions. In addition, record keeping 

requirements will require additional staffing just to take readings. 

The commenter concludes that the rule will have major economic 

impacts and potential to shut down a number of operations. Another 

commenter stated that they surveyed 10 testing firms and found the 

median cost of D/F testing to be $12,000 per source based on tests 

on medical/infectious waste incinerators and concluded that the 

average sweat furnace testing costs could easily be 25% of the capital 

cost of a furnace ($45,000), yielding a significant impact. (IV-D-13, 

IV-D-7)

Response: In response to the first commenter, EPA has revised 

the rule so that it no longer requires testing of each piece of 

equipment where sources are uncontrolled and are similar from the 

standpoint of design and operation. In addition, because area 

sources only perform an initial compliance test, they will incur 

lower costs for testing than major sources which are required to 

retest every 5 years.

Regarding the concerns of the second commenter, a manufacturer 

of sweat furnaces, EPA notes that the cost used by EPA to assess 

impacts is almost double the cost cited by the commenter. 

Furthermore, where the sweat furnace afterburner meets the final 

rule's design specifications, the owner/operator is not required to 

perform emissions testing, but must only monitor the afterburner 

operating temperature.

5.4 Comment: One commenter stated that the rule should 

provide incentives to identify innovative approaches to emission 
94

reductions, and if not, it should allow innovative approaches with 

the least net economic effect. (IV-D-9)

Response: The rule does provide for the use of pollution 

prevention and innovative approaches to reduce emissions by allowing 

owners/operators to develop site-specific plans for monitoring and 

operations, grouping in-line fluxers and group 1 furnaces to allow 

SAPU compliance demonstrations to be conducted in the most 

cost-effective way, and requiring site specific work practices to 

prevent or limit the use of materials in furnace operations that 

result in HAP emissions.

5.5 Comment: Benefits of recycling should be considered in 

regulating this category. Recycling offsets environmental harms 

associated with production and use of virgin materials. Because 

recycling itself is a pollution prevention activity the Agency might 

consider providing a recycling credit that reduces or modifies limits 

for affected facilities, such as an offset determination that 

contributes toward meeting emission control levels. (IV-D-27)

Response: EPA agrees that recycling is environmentally 

beneficial in that it saves resources. But because the secondary 

aluminum production industry also releases hazardous air pollutants 

listed in the Act, and the industry is listed as a source category 

for regulation under the Act, EPA is required to develop 

technology-based (MACT) standards for the industry.

5.6 Comment: One commenter took issue with certain 

health-related documents contained in the docket as well as length 

of the preamble's discussion of the health effects of the 

pollutants.(IV-D-23)

Response: The commenter's criticisms were not directed at the 

rule but at certain docket items and the discussion of health effects 

in the preamble. Although consideration of health risks do not enter 

into the analysis of regulations that are set at the floor level of 

control as is the case with this regulation, EPA believes that the 

information presented in the preamble and the supporting docket 

material is needed to fully inform the public of the health risks 

associated with the hazardous air pollutants covered by this rule.

5.7 Comment: EPA presented model results based on four model 

plants for 384 meteorological sites, the worst risk from which was 

in Hawaii. The commenter stated that because this site has unusual 

air dispersion characteristics, and EPA did not consider activity 

patterns and indoor/outdoor exposure gradients, that the potential 

impacts are overly conservative. (IV-D-23)

 The same commenter stated that the potential health impacts 
95

from HCl exposure are exaggerated due to large safety factors applied 

in developing the RfC from the Lowest Observable Adverse Effect Level 

(LOAEL). The commenter provided a review of the derivation of the 

IRIS RfC for HCl in a report by a consultant. In addition the 

consultant addressed other conservative assumptions related to the 

exposure assessment that in their opinion causes EPA’s exposure 

estimates to be overstated.

Response: The comments address methods EPA used in assessing 

exposure to hazardous air pollutants and the associated health risks. 

As noted above, the consideration of health risks do not enter into 

the analysis of regulations that are set at the MACT floor and the 

rule for secondary aluminum production facilities is set at the MACT 

floor.

5.8 Comment: One commenter feels that enforcement of the 

NESHAP will be unequal because some state agencies (e.g., South Coast 

Air Quality Management District) are better staffed and trained to 

implement new laws. The commenter is concerned that facilities in 

Southern California will be handicapped by the standards in 

comparison to facilities in other locales. (IV-D-10)

Response: EPA understands that implementation and enforcement 

of any rule may vary among agencies depending on several factors but 

believes that the differences will be minimal. In addition, nothing 

in the CAA precludes adoption of more stringent standards by any 

State.

5.9 Comment: One commenter noted that there are many 

differences between the proposed NESHAP and the control measures 

required by the state regulatory agency. This commenter stated the 

most effective way to integrate the federal and state requirements 

is to revise the state permits to incorporate the relevant federal 

requirements. The proposed amendments to 40 CFR Part 63, Subpart 

E, Approval of State Programs and Delegation of Federal Authorities, 

allow the use of district operating permits or Title V permits for 

making equivalency determinations, but the amendments place a limit 

on the number of individual sources for which permits may be used 

in determining equivalency between federal and state programs. The 

commenter opposes limits on the number of individual sources that 

can use permits to determine equivalency. (IV-D-19)

Response: The commenter's concern is in reference to State 

permit programs and is not relevant to this action.