EPA-450/3-82-005b
Revised Standards for Basic
Oxygen Process Furnaces -
  Background Information
for Promulgated Standards
     Emission Standards and Engineering Division
    U.S. ENVIRONMENTAL PROTECTION AGENCY
        Office of Air, Noise, and Radiation
      Office of Air Quality Planning and Standards
     Research Triangle Park, North Carolina 27711
            December 1985

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This report has been reviewed by the Emission Standards and Engineering Division of the Office of Air Quality Planning.1
and Standards, EPA, and approved for publication. Mention of trade names or commercial products is not intended to consti- f
tute endorsement or recommendation for use. Copies of this report are available through the Library Services Office (MD-35),
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711; or, for a fee, from the National Techni- j
cat Information Services, 5285 Port Royal Road, Springfield, Virginia 22161.
                                       Publication No. EPA-450/3-82-005b

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                      ENVIRONMENTAL PROTECTION AGENCY

                           Background  Information
                    Final Environmental  Impact Statement
                      Revised Standards  of  Performance
                     for Basic Oxygen  Process Furnaces
                                Prepared by:
Jack R. Farmer
Director, Emission Standards and Engineering Division
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina  27711
TDate)
      The promulgated standards of performance would  limit  secondary
      emissions of particulate matter from new, modified, and  reconstructed
      basic oxygen process steelmaking facilities.  The  final  standards
      implement Section 111 of the Clean Air Act  (42  U.S.C.  7411)  and  are
      based on the Administrator's determination  that the previously
      promulgated standards for BOPF's no longer  reflect application  of  the
      best demonstrated technology (BDT) for these  facilities.

      Copies of this document have been sent to the following  Federal
      Departments:  Office of Management and Budget;  Labor,  Health and Human
      Services, Defense, Transportation, Agriculture, Commerce,  Interior,  and
      Energy; the National Science Foundation; the  Council  on  Environmental
      Quality; members of the State and Territorial Air  Pollution  Control
      Adminstrators; the Association of Local Air Pollution  Control
      Officials; EPA Regional Administrators; and other  interested parties.

      For additional information contact:

      Mr. Doug Bell  :
      Standards Development Branch (MD-13)
      U. S. Environmental Protection Agency
      Research Triangle Park, North Carolina  27711
      Telephone:  (919) 541-5578

      Copies of this document may be obtained from:

      U. S. EPA Library (MD-35)
      Research Triangle Park, North Carolina  27711

      National Technical Information Service
      5285 Port Royal Road
      Springfield, Virginia  22161

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                              TABLE OF CONTENTS


Section                                                              Page

  1.0    SUMMARY	1-1

         1.1  Summary of Changes Since Proposal  	  1-1

              1.1.1  Subpart Na Rules  .  .  .,	1-1
              1.1.2  Subpart N Amendments	1-5

         1.2  Summary of Impacts of Promulgated  Action	1-10

              1.2.1  Alternatives to Promulgated  Action  	  1-10
              1.2.2  Environmental Impacts  of  Promulgated  Action.  .  1-10
              1.2.3  Energy and Economic  Impacts  of
                     Promulgated Action  	  1-11
              1.2.4  Other Considerations  	  1-11

  2.0   ' SUMMARY OF PUBLIC COMMENTS	2-1

         2.1  Emission Data	2-1

              2.1.1  Particulate Matter Test Reports	2-1
              2.1.2  Teemi'ng Emission  Factor	'	  .  2-3

         2.2  Affected Facilities 	  	

              2.2.1  Definition of Affected  Facilities	2-3
              2.2.2  Definition Clarification	2-6
              2.2.3  Selection of Affected  Facilities  .  	  2-7
              2.2.4  Teeming and Hot Metal  Desulfurization	2-10

         2.3  Best Demonstrated Technology	

              2.3.1  Demonstration of  Operating  Practices  	  2-12
              2.3.2  Roof-mounted Electrostatic  Precipitators  . .  .  2-13
              2.3.3  Fume Suppression	  2-14
              2.3.4  Capture Efficiency of  Auxiliary
                     Hooding for Bottom-Blown  Furnaces	2-17
              2.3.5  Capture Efficiency of  Building  Evacuation
                     Systems	2-18

         2.4  Numerical Emission Limits  ........  	  2-18

              2.4.1  Mass Standard for Secondary  Emission
                     Collection Devices  	  2-18
              2.4.2  Closed Hood Furnace  Primary  Control  Device
                     Emission Limit 	  2-19
              2.4.3  Allowance for Oxygen Blowing During
                     Bottom-Blown Vessel  Turndown 	  2-20
              2.4.4  Opacity Limit for Bottom-Blown  Furnaces.  . .  .  2-21
                                      IV.

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                        Table of Contents  (concluded)
Section                                                              Page

         2.5  Visible Emission Standards.  .............   2-22

              2.5.1  Reference Method  9	   2-22
              2.5.2  Three-Minute Average  	   2-27
              2.5.3  Alternative Mass  Emission  Limits  	   2-33
              2.5.4  Ancilliary Operations	2-34

         2.6  Emission Testing and Monitoring  	

              2.6.1  Revised Test Time for  Primary  Emissions.  .  .  .   2-35-
              2.6.2  Revised Steel Production  Cycle 	   2-36
              2.6.3  Secondary Emissions Performance Test  	   2-37
              2.6.4  Secondary Control Device  Monitoring	2-38
              2.6.5  Process Monitoring  	   2-39
              2.6.6  Secondary Emission  Steel  Production
                     Cycle	  .   2-40

         2.7  Equipment, Design, and Operating  Specifications  .  .  .   2-41

              2.7.1  Operating Practices.	2-41
              217.2  Pperating Specifications  	   2-43
              2.7.3  Consideration of  Baghouse  Pressure  Drop
                     Monitoring	•  •   2-44

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                              LIST OF TABLES
Title

 2-1   List of Commenters on  Proposed  Standards

 2-2
      Hot Metal Transfer Flame Suppression  Evaluation  for  the
      BOPF New Source Performance Standard  (NSPS)  Revision .  .  .

2-3   Observer Error for 3-Minute and 6-Minute  Opacity
      Averaging	

2-4   Standard Deviation of Error (Between-Observer  Precision)
      for Different Averaging Times  (By  Location  and  Smoke
      Color)	  .  .
Page

 2-2


 2-16


 2-29



 2-32

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                              1.  SUMMARY

     On January 20, 1983, the U.S. Environmental Protection Agency
(EPA) proposed standards of performance for basic oxygen process
furnaces (BOPF's) under authority of Section 111 of the Clean Air Act
(48 FR 2658).  Public comments were requested on the proposal in the
Federal Register.  A total of five sets of public comments were received.
Four commenters were industry representatives; also commenting was one
private environmental engineering firm.  The comments that were sub-
mitted, along with responses to these comments, are summarized in this
document.  The summary of comments and responses serves as the basis
for revisions made to the standards between proposal and promulgation.
1.1  SUMMARY OF CHANGES SINCE PROPOSAL
     The proposed rules for BOPF's were contained in two Subparts of
40 CFR Part 60—-Subparts Na and N.  The following two sections describe
the proposed and final rules.
1.1.1  Subpart Na Rules
     As proposed, Subpart Na applied to secondary emissions from
top-blown and bottom-blown BOPF's and to hot metal  transfer and skimming
stations.  Visible emissions from the BOPF shop roof monitor or other
building openings were limited to no more than 10 percent opacity
during the operation of any top-blown BOPF, except that an opacity
greater than 10 percent but less than 20 percent could occur once per
steel  production cycle.   Visible emissions from the BOPF shop roof
monitor or other building openings were limited to no more than 30 per-
cent opacity during the operation of any bottom-blown BOPF, except
that an opacity greater than 30 percent but less than 60 percent could
occur twice per steel production cycle.   Mass emissions of particulate
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 matter exiting "a control device were limited to no more than 23 mg/dscm
 (0.010 gr/dscf).  The opacity of visible emissions exiting the control
 device was limited to no more than 5 percent.   Compliance with the
 proposed visible emission standards was determined by Reference Method 9
 through 3-minute averages.   Compliance with the proposed mass standard
 for the collection device was determined with the use of Reference
 Method 5.
      A roof-mounted electrostatic precipitator (RMESP) used to control
 secondary emissions from an affected facility was exempted from the
 mass and opacity standards for secondary emission control devices.   A
 device used to control both primary and secondary emissions also was
 exempted from the secondary emission control device mass and opacity
 standards.
      A number of changes have been made to Subpart Na since proposal.
 The most significant change is in the applicability of the final
 standards  resulting from the withdrawal of the roof monitor opacity
.standard for bottom-blown BOPF's.   The rationale for this change is
 discussed  in Chapter 2,  Section 2.4, entitled "Numerical Emission
 Limits."
      The final rules apply to secondary emissions of particulate
 matter from top-blown BOPF's and hot metal  transfer and skimming
 stations used with bottom-blown or top-blown BOPF's that have been
 constructed, modified, or reconstructed after January 20, 1983.
 Visible emissions from shop roof monitors (or other building openings)
 may not exhibit  more than 10 percent opacity during the steel  production
 cycle of a top-blown BOPF and during hot metal  transfer or skimming
 for a bottom-blown BOPF, except that an opacity greater than 10 percent
 but less than 20 percent may occur once per steel  production cycle.
 Visible emissions from the  shop roof monitor during the bottom-blown
 furnace cycle (i.e., the steel  production cycle excluding hot metal
 transfer and skimming) are  not subject to the  roof monitor opacity
 standard.   Mass  emissions from a secondary emission collection device
 are limited to 23 mg/dscm (0.010 gr/dscf).   Control device opacity is
 limited to 5 percent.   These emission limits also apply to top-blown
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 BOPF's and to hot metal  transfer stations or skimming stations used
 with a bottom-blown or a top-blown BOPF.   Under the final  rules,  fume
 suppression systems are  exempt from the mass and opacity limits for
 the secondary emission collection device, as is any device used to
 control  primary and secondary emissions.   RMESP's are not  exempt from
 the final  mass and opacity standards for secondary emission collection
 devices.
      Numerous clarifying changes also have been made to  §60.141a,
 which includes definitions for terms used in the secondary emission
 standards.   For example,  the  definition of "hot metal  transfer" was
 expanded to include the  transfer of molten iron from the torpedo  car
 to  the charging ladle, or from the torpedo car  to an intermediate
 vessel  and from the intermediate vessel  to the  charging  ladle.
 Definitions proposed for "primary emissions"  and "secondary emissions"
 also  were  expanded and a new  definition  for "primary emission  control
 system"  was added,  as were definitions  for new  technologies, such  as
 fume  suppression  systems.   The definition of  "startup" was  deleted
 from  the final  rule because the  General  Provisions  of 40 CFR Part  60
 now include a definition  for  this  term.   Additionally, the  definition
 of  "steel  production cycle" was  expanded  to  include  preheating  (when
 used)  and  vessel  turnup,  as well  as  vessel  turndown, during sampling
 operations.
      The monitoring requirements  for  the  secondary emission control
 system were  also  modified.  As proposed,  §60.143a required the  use  of
 a monitoring  device  that  continuously records the various exhaust
 ventilation  rates  through  the  secondary emission control system for
 each phase  of each  steel  production cycle.  The  final rule specifies
 that the owner or  operator  install, calibrate, operate,  and maintain a
 monitoring  device  that continually measures and  records  for each steel
 production cycle the various exhaust ventilation rates or levels of
 exhaust ventilation through each duct of the secondary emission control
 system for each phase of each steel production cycle.  The final
monitoring provisions also include a requirement for the semiannual
 reporting of monitoring measurements over any 3-hour period that
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averages more than 10 percent below the average levels maintained
during the most recent performance test for demonstrating compliance
with the mass standard for secondary emission collection devices.  A
similar provision also was added to require semiannual reporting if a
scrubber primary emission control device is used for secondary emission
collection.  Operating requirements were also added to §60.143a for
the use of strip chart recorders.  The rationale for these changes is
discussed in Chapter 2, Section 2.7, entitled "Equipment, Design, and
Operati ng Speci fi cati ons."
     Several clarifying changes were made to §60.144a regarding test
methods and procedures.  First, §60.144a(b)(l), which provided for the
aggregation of visible emission observations from multiple exit points,
was deleted from the final rule.  A new provision was added that
provides instructions for comparing the velocity readings obtained by
Reference Method 2 to the step changes recorded by a device that
monitors the level of exhaust ventilation.   The sampling requirements
for secondary emissions by Reference Method. 5 were also modified.  The
proposed rule specified that the sampling for each run is to continue
for a sufficient number of steel production cycles to ensure a total
sample volume of at least 2.27 dscm (80 dscf) for each run.  The final
rule increases the requirement for total sample volume to 5.67 dscm
(200 dscf).  A new provision was also added that allows shorter sampling
times and smaller sample volumes, subject to approval by the Administrator,
when necessitated by process variables or other factors.   This revision
is discussed in Chapter 2, Section 2.6, entitled "Emission Testing and
Monitoring."
     Many of the compliance provisions proposed under §60.145a were
expanded or clarified.  Sections 60.145a(a) and (b) were clarified
specifically to allow an owner or operator of a BOPF shop that normally
operates two furnaces with overlapping cycles to shut down one furnace
during compliance tests for both mass and visible emissions.  A new
provision also was added that requires the owner or operator to operate
the secondary emission control system for the furnace being tested at
exhaust ventilation rates (or levels) through each duct of the system
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 that are appropriate for single-furnace operation.  Following the
 compliance test, the owner or operator must operate the system so that
 exhaust ventilation rates (or levels) through each duct of the secondary
 system are no lower than 90 percent of the exhaust ventilation rates
 (or levels) established for each duct during the most recent compliance
 test.  The rationale for this change is discussed in Chapter 2, Sec-
 tion 2.7, entitled "Equipment, Design, and Operating Specifications."
     Section 60.145a was also clarified to define specifically the
 period for hot metal transfer or skimming visible emission observations.
 For both hot metal transfer and skimming, visible emission observations
 begin with the start of the operation and terminate 3 minutes after
 completion of the operation.  The final rules also require that for
 visible emission compliance tests, all visible emission observations
 are to be identified and recorded in conjunction with the starting
 times and stopping times of regulated operations in the steel production
 cycle.   The final rules require the use of 3-minute averages for
 visible emission observations by Reference Method 9.
     Section 60.145a also was expanded to.include instructions for
 determining compliance with the 5-percent opacity standard and the
 0.010-gr/dscf concentration standard for the secondary emission collec-
 tion device.   To determine compliance with the opacity standard,  the
 owner or operator would construct consecutive 3-minute averages for
 each steel  production cycle.   Compliance would be achieved if no
 3-minute average exceeded 5 percent.   To determine compliance with the
mass standard, the owner or operator would determine the concentra-
tion of particulate matter in exhaust gases exiting the secondary
emission collection device,  according to Reference Method 5.   Compli-
ance would be  achieved if the measured value did not exceed 23 mg/dscm
 (0.010  gr/dscf).   Additionally,  instructions for determining compli-
ance with the  proposed roof monitor opacity standard for bottom-blown
furnaces were  deleted from the final  rules.
1-1.2  Subpart N Amendments
     Subpart N contains standards  of performance that regulate primary
emissions of particulate matter  from BOPF's constructed,  reconstructed,
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or modified after June 11, 1973.  On January 20, 1983, minor amendments
were proposed for Subpart N BOPF's constructed, reconstructed, or
modified between June 11, 1973, and January 20, 1983.  These proposed
amendments did not revise the existing emission limit of 50 mg/dscm
(0.022 gr/dscf) for mass emissions of particulate matter from the
primary emission control device or the .existing opacity limit for
visible emissions exiting the primary emission control device.  The
existing standard limits visible emissions exiting the primary emission
control device to an opacity of less than 10 percent, except that an
opacity greater than 10 percent but less than 20 percent may occur
once per steel production cycle.  Additionally, no changes were proposed
to the existing monitoring or reporting requirements.  The proposed
amendments did revise the test method instructions for sampling of
mass emissions by Reference Method 5.   The existing standard required
a sampling rate of at least 0.9 dscm/hr (0.53 dscf/min); the proposed
amendments required a minimum sample volume of at least 0.9 dscm
(32 dscf).  It should be noted that the minimum sample volume of
9.9 dscm (32 dscf) proposed under subparagraph (b)(l) was the result
of a Federal Register misprint; a minimum sample volume of 0.9 dscm
(32 dscf) was intended.   With the exception of the sample volume
requirement, no other changes to the test methods and procedures for
determining compliance with the mass or visible emission standards
were proposed for these Subpart N BOPF's.
     The proposed amendments also expanded the definition of a "basic
oxygen furnace" to exclude specifically open hearth, blast, or reverbera-
tory furnaces.  No other definitional  changes applicable to Subpart N
BOPF's were proposed.
     A number of changes have been made since proposal to the final
standards for these Subpart N BOPF's.   The proposed minimum sample
volume requirement has been increased to at least 1.5 dscm (53 dscf).
This revision is discussed in Chapter 2, Section 2.6, entitled "Emission
Testing and Monitoring."  With the exception of this increased sample
volume requirement, no changes have been made to the existing test
methods and procedures for determining compliance with the mass and
opacity limits for primary emission control device by these Subpart N
BOPF's.
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     Since proposal on January 20, 1983, EPA has become aware of a
difference in furnace cycle time between top-blown and bottom-blown
furnaces that may impact measured emission concentrations for those
facilities regulated under Subpart N.  Bottom-blown furnaces in general
have shorter oxygen blowing periods than top-blown furnaces.  The
testing provisions for those BOPF's constructed, reconstructed, or
modified after June 11, 1973, but on or before January 20, 1983, allow
testing from the beginning of the oxygen blow, or scrap preheat if
practiced, until just prior to tapping.  The bulk of the particulate
emissions.occur during the oxygen blow, however.  With a shorter
oxygen blowing period and roughly the same length nonblowing period as
top-blown furnaces, the bottom-blown furnaces are allowed a greater
proportion of test time during nonblowing periods, thus tending to
dilute the measured particulate concentration more than is allowed for
top-blown furnaces.  To remedy this inequity due to furnace cycle
differences, EPA intends to propose revised sample period requirements
and mass standards as may be appropriate for top-blown and bottom-blown
furnaces under Subpart N as part of the 4-year NSPS review cycle.
     No changes were proposed to the monitoring requirements specified
in §60.143 of the existing standards.   The final rules would continue
these requirements with certain minor changes.   Under §60.143(b)(2), a
monitoring device is required for the continuous measurement of the
water supply pressure to the control  equipment, and the pressure
sensor or tap must be located close to the water discharge point.   The
existing standards then state that the Administrator may be consulted
for approval of alternative locations for the pressure sensor or tap.
Under the final  rules,  alternative locations for the pressure sensor
or tap must be approved in advance by the Administrator.   Also,  the
word "continuous" was changed to "continually"  to avoid confusion  with
continuous monitoring system requirements specified under the General
Provisions of 40 CFR Part 60.   Section 60.143 of the existing standards
also requires quarterly reports of all  monitoring measurements  over
any 3-hour period that  averages more  than 10 percent below the  average
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levels maintained during the most recent performance test for
demonstrating compliance with the mass standards.  The final standards
reduce the reporting frequency from quarterly to semiannually.
     No changes to the definition for a BOPF have been made since
proposal.  However, §60.141 of the final rules includes a revised
definition of "steel production cycle" for Subpart N BOPF's and a new
definition for "primary emissions."  For Subpart N BOPF's (i.e.,
constructed, reconstructed, or modified after June 11, 1973, but on or
before January 20, 1983), the existing definition of "steel production
cycle" has been expanded to include sampling (vessel turndown and
turnup) operations.  "Primary emissions" means particulate matter
emissions from the BOPF generated during the steel production cycle
and captured by the primary emission control system.  Also, the
definition of "startup" was deleted from §60.141 because a definition
is now included in the General Provisions of 40 CFR Part 60.
     Also on January 20, 1983, amendments to Subpart N were proposed
to regulate BOPF's constructed, reconstructed, or modified after
January 20, 1983.   These proposed standards adjusted the mass emissions
limits and the test methods and procedures for determining compliance.
For BOPF's with a closed hood primary emission control system, the
proposed amendments limited mass emissions of particulate matter to no
more than 68 mg/dscm (0.030 gr/dscf), as measured for the primary
oxygen blow.   For BOPF's with an open hood primary emission control
system, mass emissions of particulate matter were limited to no more
than 50 mg/dscm (0.022 gr/dscf), as measured for the primary oxygen
blow.   The proposed amendments to the test methods and procedures for
sampling of mass emissions by Reference Method 5 specified that sampling
for each run must continue for an integral number of primary oxygen
blows with a total duration of at least 60 minutes.   A minimum sample
volume requirement of 0.9 dscm (32 dscf) also was proposed.
     No changes were proposed to the existing opacity standard for
primary emission control devices.   Under the proposed amendments,
visible emissions  from control devices for open or closed hood primary
control systems were limited to no more than 10 percent opacity,
except that an opacity greater than 10 percent but less than 20 percent
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could occur per steel production cycle.  No changes to the test methods
and procedures for determining compliance with the opacity limit were
proposed.
     A proposed definition for "primary oxygen blow" also was added to
§60.141.  The proposed definition defined "primary oxygen blow" as the
period in the steel production cycle of a BOPF during which a high
volume of oxygen-rich gas is introduced to the bath of molten iron by
means of a lance inserted from the top of the vessel or through tuyeres
in the bottom or the bottom and sides of the vessel.  Reblows were
excluded from the proposed definition, as was the introduction of
nitrogen through tuyeres in the bottom or bottom and sides of the
vessel.
     The final Subpart N standards for BOPF's constructed, reconstructed,
or modified after January 20, 1983, continue the proposed requirements
with few exceptions.   No changes to the adjusted limits for mass emis-
sions from open or closed hood primary control systems have been made
since proposal, although a new operational requirement has been added.
During and after any compliance test, the owner or operator must
operate the gas cleaning device during any reblow in a manner identical
to operation during the primary oxygen blow.   The final rules require
these BOPF's to determine compliance with the adjusted mass emission
limits by sampling during the primary oxygen blow.   No changes to the
proposed definition of "primary oxygen blow"  have been made since'
proposal.  Except for an increased sample volume requirement, no
changes to the Reference Method 5 test methods and procedures for
determining compliance with adjusted mass emission limits have been
made since proposal.   The proposed minimum sample volume requirement
of 0.9 dscm (32 dscf) has been increased to at least 1.5 dscm (53 dscf).
This change is discussed in Chapter 2, Section 2.6,  entitled "Emission
Testing and Monitoring."  As proposed, shorter sampling times and
smaller sample volumes are permitted when necessitated by process
variables or other factors,  subject to approval  by the Administrator.
     No changes have  been made to the visible emission limit applied
to these BOPF's.   As  proposed,  visible emissions from control  devices
for open or closed hood primary control  systems  are  limited to no more
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than 10 percent opacity except that an opacity greater than 10 percent
but less than 20 percent may occur once per steel production cycle.
Under the final rules, compliance with the visible emission standard
is determined according to the provisions of the existing primary
standard.  However, the definition of "steel production cycle" for
these BOPF's has been revised since proposal to include specifically
sampling (vessel turndown and turnup) and deslagging operations.
     BOPF's constructed, reconstructed, or modified after January 20,
1983 also are subject to the amended monitoring and reporting require-
ments.  As discussed previously, §60.143 has been clarified to require
advance approval by the Administrator for alternative locations for
the monitoring device pressure sensor or tap.  The final standards
also reduce the frequency of reporting requirements from quarterly to
semiannually.
1.2  SUMMARY OF IMPACTS OF PROMULGATED ACTION
1.2.1  Alternatives to Promulgated Action
     The regulatory alternatives are discussed in Chapter 6 of'the
background information document (BID) for the proposed standards.
These regulatory alternatives reflect the different levels of emission
control from which one is selected that represents best demonstrated
technology (BDT), considering costs, nonair quality health, and environ-
mental and economic impacts for secondary emission control of BOPF's.
Regulatory Alternative II, the alternative selected as the basis  of
the proposed secondary emission standards, was revised to account for
withdrawal of the roof monitor opacity standard for bottom-blown
furnaces.  As revised, Regulatory Alternative II includes BDT controls
for top-blown furnaces and for hot metal transfer stations and skimming
stations used with bottom-blown or top-blown furnaces.
1.2.2  Environmental Impacts of Promulgated Action
     The regulatory alternatives and their environmental impacts  are
discussed in Chapters 6 and 7 of the BID for the proposed standards.
The environmental impacts remain unchanged since proposal.  Withdrawal
of the proposed roof monitor opacity standard for secondary emissions
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from bottom-blown furnaces would not affect the environmental impacts
because impacts for the period 1981 through 1986 were based on estimates
of increased capacity projected for top-blown furnaces.
     Comments received from the Office of Water indicate that the gas
cooling and conditioning system used with an electrostatic precipitator
(ESP) must be designed as a total evaporation system because the steel
industry effluent regulation (40 CFR 420, May 27, 1982) specifies no
discharge from these systems.  Text from the BID for the proposed
standards also has been revised to include a further discussion of the
water pollution impact of Regulatory Alternative III if a wet or
semiwet ESP were used in lieu of other control systems.  A detailed
discussion of these revisions may be found as Item IV-B-7 in Docket
No. A-79-6.  With the changes noted in this docket submission, the
analysis of environmental impacts in Volume I of the BID is now con-
sidered the final environmental impact statement (EIS) for the promul-
gated standards.
1.2.3. Energy and Economic Impacts of Promulgated Actions
     Energy and economic impacts are discussed in Chapters 7, 8, and 9
of the BID for the proposed standards.   These estimated nationwide
impacts have remained unchanged since proposal.
     Further analysis of secondary emission control technologies
indicates that the cost effectiveness of the control technologies that
can be used to comply with the standards ranges from $1,665 to $3,727
per ton of particulate matter removed for furnace emissions and from
$1,755 to $3,100 per ton of particulate matter removed for hot metal
transfer stations.   In addition, new BOPF's may be able to employ
lower cost, innovative hot metal transfer controls.  However, the
aggregated cost effectiveness of $2,245 per ton for secondary emission
controls has not been revised since proposal.
1.2.4  Other Considerations
     1.2.4.1  Irreversible and Irretrievable Commitment of Resources.
None of the regulatory alternatives examined would result in the
irreversible or irretrievable commitment of resources in that a tradeoff
is made between short-term environmental  gains at the expense of
long-term environmental  losses or vice  versa.
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     The  final  regulations  are  standards of performance and therefore
do not  require  the  use of any particular control technology with which
to achieve compliance.  The regulatory alternative selected as the
basis of  the standards (Regulatory Alternative  II) would allow the
continued use of both types of  primary control  systems (open and
closed  hood) currently favored  by the industry.  In addition, the
standards would not preclude the use of any other technology capable
of achieving the emission limits and would encourage the use of
innovative technology such  as fume suppression  systems.
     1.2.4.2  Environmental  and Energy Impacts  of Delayed Standards.
Delay of  promulgated secondary  emission standards for this source
category  was not considered a regulatory alternative because adequately
demonstrated control technology exists upon which the final standards
can be  based.   Also, construction, modification, or reconstruction of
three BOPF shops is estimated to commence during the 5-year period
following proposal  of the standards.   Nationwide uncontrolled secondary
and controlled  primary emissions of particulate matter at these shops
would total about 3,221 Mg/yr (3,551 ton/yr) in the absence of the
proposed  standards.  These  emissions would be in addition to the
uncontrolled secondary emissions from existing shops.
     1.2.4.3  Urban and Community Impacts.   The promulgated standards
will  have a beneficial urban and community impact.   Reduction in
particulate matter will  reduce  health risks for workers and the com-
munities  surrounding new BOPF steelmaking facilities and improve the
overall  environmental  quality.
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                    2.  SUMMARY OF PUBLIC COMMENTS

     A total of five letters commenting on the proposed standards and
the background information document (BID) were received.  A public
hearing was not requested during the prescribed period; consequently,
no public hearing was held.  A list of the commenters, their affilia-
tions, and the U.S. Environmental Protection Agency (EPA) docket
numbers assigned to their correspondence is given in Table 2-1.
     For the purpose of orderly presentation, the comments have been
categorized under the following topics:
     1.   Emission Data
     2.   Affected Facilities
     3.   Best Demonstrated Technology
     4.   Numerical Emission Limits
     5.   Visible Emission Standards
     6.   Emission Testing and Monitoring
     7.   Equipment Design and Operating Specifications
     The comments, the issues they address, and EPA's responses are
discussed in the following sections of this chapter.
2.1  EMISSION DATA
2.1.1  Comment:   (IV-D-2)  One commenter suggested that particulate
matter emission factor reports for tests of basic oxygen process
furnace (BOPF) hot metal charging and tapping at Republic Steel Corporation,
Kaiser Steel Company, and Inland Steel Company be included in the data
analysis of Volume I of the BID.   He also believed that a report on
particulate mass and particle size measurements for the hot metal
desulfurization plant at Kaiser Steel  Company should have been included.
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     TABLE 2-1.  LIST OF COMMENTERS ON PROPOSED STANDARDS FOR THE BOPF
              NEW SOURCE PERFORMANCE STANDARD (NSPS) REVISION
Docket item number1
Commenter and affiliation
     IV-D-1
     IV-D-2
     IV-D-3
     IV-D-4
     IV-D-5
E. F. Young, Jr.
American Iron and Steel Institute
1000 16th Street, N.W.
Washington, DC  20036
Date:  March 15, 1983

Jim Steiner
Pape and Steiner Environmental
 Services
5801 Norris Road
Bakersfield, CA  93308
Date:  April 4, 1983

D. A. Woodring
Republic Steel Corporation
P.O.  Box 6778
Cleveland, OH  44101
Date:  April 4, 1983

David M.  Anderson
Bethlehem Steel Corporation
Bethlehem, PA  18016
Date:  April 4, 1983

Frank P.  Partee
Compliance and Liaison Department
Ford Motor Company
One Parklane Boulevard
Dearborn, Michigan  48126
Date:  April 13, 1983
 The docket number for this project is A-79-6.   Dockets are on file at EPA
 Headquarters in Washington,  DC,  and at the Office of Air Quality Planning
 and Standards (OAQPS) in Durham,  NC.
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     Response:  Not all of the reports named by the commenter had been
finalized and distributed at the time emission data were being analyzed.
Emission factor data used in the BID were taken from "Particulate
Emission Factors Applicable to the Iron & Steel Industry" (EPA-450/4-
79-028), which contains material similar to that in the emission
factor reports named by the commenter (II-A-46).  This earlier report
was the source for revised emission factors published in "Supplement
Number 11 for Compilation of Air Pollutant Emission Factors, Third
Edition," AP-42, published by EPA, October 1980.  Information in the
test reports named by the commenter and not used in this review of the
BOPF standard will be evaluated during the next 4-year review of the
BOPF standard.  The selection of emission factors used in the development
of the standards is further discussed in the response to comment
2.2.3.
2.1.2  Comment:   (IV-D-2)  One commenter suggested that the teeming
emission factor of 35 g/Mg (0.07 Ib/ton) of steel is based on unleaded
heats and that leaded heats have an emission factor of 0.81 Ib/ton,
72 percent of which is of inhalable particle size.   He also recommended
that secondary emissions from teeming be included in the proposed
rulemaking:
     Response:  The commenter is correct in suggesting that an unleaded
heat emission factor was used to assess teeming emissions.   While the
leaded heat emission factor is considerably larger, available informa-
tion suggests that leaded heats comprise only a small portion of the
total number of BOPF heats.   In the absence of specific information to
the contrary, a determination was made that the emission factor for
unleaded heats would be more representative of normal industry practice.
The rationale for not controlling teeming at present is discussed in
the response to comment 2.2.4.
2.2  AFFECTED FACILITIES
2.2.1  Comment:   (IV-D-1 and IV-D-4)  Two commenters questioned the
proposed definitions of the BOPF vessel, hot metal  transfer station,
and skimming station as separate, affected facilities.   The commenters
believe that construction, modification, or reconstruction of a hot
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metal  transfer  or  skimming  station  could  subject  an existing BOPF  shop
to  the proposed secondary emission  opacity  standard.  They also pointed
out that  because opacity readings are taken at  shop openings, vents,
and monitors  (where they could  be intermingled  with emissions from
unregulated operations  in the shop), enforcement  officials could
require compliance from the entire  existing shop.
     Response:   The choice  of the affected  facility for this standard
is  based  on interpretation  of Section 111 of the  Act and judicial
construction  of its meaning.  Under Section 111,  the NSPS must apply
to  "new sources."  "Source" is  defined as "any  building, structure,
facility, or  installation which emits or may emit any air pollutant"
[lll(a)(3)].  Most industrial plants, however,  consist of numerous
pieces  or groups of equipment that  emit air pollutants and that might
be  viewed as  "sources."  The term "affected facility" is used, there-
fore,  to  designate the  equipment, within a  particular kind of plant,
which  is  chosen  as the  "source" covered by  a given standard.
    .When the affected  facility is  chosen,  a decision must be made
concerning which pieces or groups of equipment  are the appropriate
units  for separate emission standards in the particular industrial
context involved.  This decision is made by examining the situation in
light of  the terms and purpose of Section 111.   One major consideration
in this examination is that the use of a narrower definition results
in bringing replacement equipment under the NSPS  sooner; if,  for
example,  an entire plant were designated as the affected facility, no
part of the plant would be covered by the standard unless the plant as
a whole is "modified."  If,  on the other hand,  each piece of equipment
is designated as the affected facility,  as each piece is replaced, the
replacement piece will be a new source subject to the standard.
Because the purpose of Section 111 is to minimize emissions by applica-
tion of the best demonstrated control  technology (considering cost,
other health and environmental  effects,  and energy requirements)  at
all  new and modified sources,  the presumption is that a narrower
designation of the affected facility is  proper.   This designation
ensures that new emission sources within plants will  be brought under
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 the  coverage  of  the  standard  as  they  are  installed.   It  was  for  this.
 reason  that the  emission  sources were defined  as  separate, affected
 facilities.
     As  explained  in 48 FR  2658, the  proposed  standards  of performance
 for  secondary emissions would apply only  to  a  BOPF,  hot  metal  transfer
 station, or skimming station  that commenced  construction, modification,
 or reconstruction  after January  20, 1983.  (Note  that the final  rules
 apply only to top-blown BOPF's and to hot metal transfer stations or
 skimming stations  used for  bottom-blown or top-blown BOPF's.)  It
 should  be noted  that although a  plant may contain both affected  facil-
 ities and existing,  nonaffected  facilities,  the modification or  recon-
 struction of  an  existing, nonaffected facility would not subject any
 other existing nonaffected  facility to the requirements  of the proposed
 regulation.   Only  the facility constructed,  modified, or reconstructed
 would become  subject to the standards  of  performance.  For example,
 the  addition  of  a  new furnace to an existing shop would  subject  only
 the  new furnace  to the secondary emission standards; an  existing hot
 metal transfer or  skimming  station would  not be affected unless  it was
 also modified or reconstructed.  The  effects of new construction,
 modifications, and reconstructions on  affected and nonaffected facil-
 ities are discussed  further in Chapter 5  of  the BID for  the proposed
 standards.
     The proposed standards also recognize that, at times, visible
 emissions from the shop roof monitor  (or other building  openings) may
 occur from unaffected facilities or unregulated ancilliary operations.
 For this reason, the final rules allow the owner or operator to  operate
 only one furnace during compliance testing for mass and  visible  emission
 limits.   The owner or operator also may choose to suspend all unaffected
 shop operations during the test.   The final   regulation also requires
that all visible emissions be identified in conjunction with the
starting and stopping times of regulated process operations.   Conse-
quently, the use of a process observer is encouraged.  A process
observer inside the shop during the testing can reduce substantially
the possibility that emissions from unaffected facilities or operations
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are included in the opacity observations.  These provisions are adequate
to ensure that emissions from other operations or facilities are not
adversely incorporated in the opacity observations.
2.2.2  Comment:  (IV-D-4)  One commenter requested clarification of
the definitions for the affected facilities.  This commenter indicated
a potential discrepancy between §60.140a(a) of the regulation, which
cites the affected facilities, and §60.142a(a), which contains the
proposed secondary emission limits.  The proposed emission limits
appear to apply only to BOPF secondary emissions (i.e., emissions
escaping the BOPF primary control system).   Consequently, the proposed
emission limits would not apply to hot metal transfer and skimming
stations.
     Response:   Under §60.140a(a), the BOPF, hot metal transfer station,
and skimming station are designated as the affected facilities subject
to the proposed secondary emissions standards.  Section 60.142a specifies
the proposed emission limits for secondary emissions from affected
facilities.  The hot metal transfer station and the skimming station,
as affected facilities, are subject to the proposed standards for
particulate matter under §60.142a.
     The proposed standards define secondary emissions as "particulate
emissions that escape capture from the BOPF primary control system."
Hot metal transfer and skimming operations do not generally occur in
proximity to the furnace.  Consequently, emissions from these operations
are not captured by the BOPF primary control system.  Because these
emissions escape capture by the furnace control system, they are
considered secondary emissions.  Therefore, the proposed standards for
secondary particulate matter apply to secondary emissions from the
furnace, in combination with "secondary" emissions from hot metal
transfer and skimming operations.  The final rule clarifies the
definition of "secondary emissions" by specifically including emissions
from hot metal  transfer and skimming.   Also included in the final
definition are particulate matter emissions that escape from openings
in the primary emission control system, such as from lance hole openings,
gaps or tears in the ductwork of the primary emission control system,
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 or leaks in hoods.   Similar clarifying changes were also made to the
 definition of "primary emissions," and new definitions for "primary
 emission control  system"  and "secondary emission control system" also
 were added to the final  rule.
 2.2.3  Comment:   (IV-D-4)  One commenter questioned the selection of
 affected facilities,  based on "over-stated"  emission factors  and, in
 one case,  lack of supporting data.   He pointed out that the emission
 factors for uncontrolled  secondary emissions of particulate matter
 from hot metal  transfer and BOPF  charging are considerably higher than
 are emission factors  used in two  more  recent reports,  "Particulate
 Emission Factors  Applicable to the Iron and  Steel  Industry" (EPA-450/4-
 79-028) and "Fugitive Dust Emission Factor Update  for  AP-42"  (Draft).
 The commenter also  stated that uncontrolled  emissions  from hot metal
 transfer and charging emissions from top-blown vessels are insignifi-
 cant compared to  BOPF primary  (oxygen  blowing) emissions.   In addition,
 the commenter questioned  the legal  justification for controlling
 skimming emissions  when no data were available regarding the magnitude
 of  these emissions  and when no attempt was made to  quantify these
 emissions.
      Response:  The BOPF,  hot  metal  transfer station,  and skimming
 station were  selected for regulation in the  proposed rules  because
 adequately  demonstrated control technology exists,  considering costs,
 upon  which  the proposed standards can  be  based, and  because these
 facilities  account  for about 1,355  ton/yr of  uncontrolled  secondary
 emissions of  particulate  matter for  a  typical  BOPF  shop  operating two
 272-Mg  (300-ton) top-blown  furnaces.
     The emission factors  used to estimate uncontrolled  secondary
 emissions were the most current factors available at the time of the
 data analysis.  It should be noted that AP-42  (Supplement 11)  provided
 one set of emission factors for selected operations.  However, a
 review of these emission factors revealed that they were based on
tests for bottom-blown vessels.  The source of these AP-42 emission
factors was the 1979 EPA report, "Particulate Emission Factors Applic-
able to the Iron and Steel Industry" (EPA-450/4-79-028).  Because this
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latter report also Included the best emission factors currently avail-
able for top-blown furnaces, these top-blown furnace emission factors
were used in the data analysis.
     Uncontrolled secondary emissions from hot metal transfer at a
typical shop are estimated at 286 ton/yr for top-blown furnaces, based
on an emission factor of 0.19 Ib/ton hot metal poured.  Controls
(local hooding ducted to a baghouse) are available for the hot metal
transfer station at a reasonable cost per ton of emission reduction.
For these reasons, the hot metal transfer station was selected for
control as an affected facility.
     The skimming operation in new plants is generally performed at
the hot metal transfer station, or immediately adjacent to it, following
the hot metal transfer operation.   No emission factor for skimming had
been reported in AP-42 or in "Particulate Emission Factors Applicable  •
to the Iron and Steel Industry" at the time of the data analysis.
However, visible emissions from this operation have been observed at
two plants based on Reference Method 22 (II-A-50, II-A-51).   Because
these emissions can be controlled by the same capture and collection
system as used for hot metal transfer emissions, at no significant
additional cost, the skimming station also was selected as an affected
facility.
     The vast majority of BOPF secondary emissions are attributable to
the various operations comprising the steel production cycle of the
BOPF vessel.   These operations include scrap charging, hot metal
charging, blowing, turndown, and tapping.   No emission factors were
available at the time of the data analysis to quantify secondary
emissions from scrap charging, the primary blow, or vessel turndown.
However, visible emissions from these operations have been observed at
the roof monitors of several shops through Reference Method 22 (II-A-50,
II-A-52, II-A-53, and II-A-54).
     Emission factors are available to estimate secondary emissions
from hot metal charging and tapping.   Based on the highest quality
emission factor for top-blown furnaces provided in "Particulate Emission
Factors Applicable to the Iron and Steel Industry" (0.4 Ib/ton of hot
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 metal  poured),  secondary emissions  from hot metal  charging are estimated
 at 603 ton/yr for a typical  shop.   Secondary tapping emissions are
 estimated  at  466  ton/yr for  top-blown  furnaces  at  a typical  shop,
 based  on the  emission  factor of 0.291  Ib/ton of steel  as  reported  in
 "Particulate  Emission  Factors Applicable to the Iron and  Steel  Industry."
     It is true that uncontrolled secondary emissions  from hot metal
 transfer and  charging  in top-blown  vessels  are  only about 3.5  percent
 of BOPF primary (oxygen blowing) emissions.   The emission factor for
 the blow,  28.6  Ib/ton,  can be compared to an emission  factor of about
 1  Ib/ton for  the  combined effect of uncontrolled emissions from hot
 metal  transfer  and charging.   However,  uncontrolled secondary  emissions
 from these operations  combined total about  1,355 ton/yr at a typical
 shop.   These  are  significant emissions  for  a typical  shop and  are
 considered even more significant on a  nationwide basis.   Uncontrolled
 secondary  emissions  of particulate  matter from  these operations consti-
 tute a major  emission  source,  even  when  considered  separate  operations.
 Data are available with which to quantify these emissions and  controls
 are available at  a reasonable cost  with  which to reduce these  emissions.
 Consequently, these  operations were selected for regulation  based  on
 their  own  merits.
     Uncontrolled  secondary  emissions emanating from furnace operations
 during the  steel production  cycle constitute the bulk of  the secondary
 emissions  from  the BOPF  steelmaking process.  Emission factors are
 available  to quantify  secondary emissions from  charging and  tapping--
 the  operations  wherein  emissions are most likely to escape capture by
 the  primary hood.   For top-blown furnaces, secondary emissions from
 charging and tapping combined total  about 1,069  ton/yr.   Controls are
 available  for these emissions at a  reasonable cost.  These controls
will also  capture  and collect secondary emissions from some other
 furnace operations at no additional  cost.  For  these reasons, the BOPF
was  selected as an affected facility under the proposed standards,  as
were the hot metal transfer station  and skimming station.
     The affected facilities  identified in the proposed rules have
been revised since proposal.   Under  the final rules, the affected
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facilities are the top-blown BOPF and hot-metal transfer and skimming
stations used for a bottom-blown or a top-blown BOPF.  The rationale
for this change is discussed in response to comment 2.4.4.
2.2.4  Comment:  (IV-D-2)  One commenter disagreed that the cost of
controlling ancillary operations not subject to the proposed standards
would be highly disproportionate to the amount of particulate collected.
The commenter indicated that teeming and hot metal desulfurization
produce significant quantities of particulates compared to regulated
secondary emission sources and that the same control technology (local
hooding ducted to a baghouse) is also applicable to these unregulated
ancillary operations.  These ancillary operations may be located in
proximity to the hot metal transfer station, allowing the use of one
common control system.  The commenter provided uncontrolled emission
factors for hot metal desulfurization, based on a total of 10 recent
tests on torpedo cars at Kaiser Steel.  He further questioned the
estimate for the quantity of emissions resulting from these unregulated
ancillary operations (8 percent of identified fugitive emissions from
BOPF shops).,  This commenter recommended that tes.ts be performed to
quantify emissions from these ancillary operations and that the control
of these unregulated ancillary operations be considered under the
proposed rulemaking.
     Response:  As explained at 48 FR 2660 and 2661, certain ancillary
operations were not selected for regulation under the proposed secondary
emission standards.   These operations include hot metal desulfurization,
dekishing, teeming,  slag handling, ladle maintenance, and flux handling.
     Prior to proposal of the secondary emission standards, no Reference
Method 9 visible emission data were available with which to characterize
emissions from hot metal desulfurization operations, although visible
emissions were observed at one plant according to Reference Method 22
procedures (II-A-51, II-B-51, II-B-52, and II-B-54).  Consequently,
visible emission testing by Reference Method 9 was conducted at a
second plant.  Mass  emission test data also were collected at this
plant, but the results of the mass emission testing have been received
only recently and currently are undergoing review.   It should be noted
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 that the  emission  factors  supplied by the  commenter were  based on this
 same mass test.  However,  preliminary review has  indicated that additional
 test data are  required  to  portray  emissions  from  this  operation accurately,
 because hot  metal  desulfurization  methods  vary widely  from plant to
 plant and may  not  be  applied  to  all  types  of metal  produced.   For
 these reasons, this operation was  not selected for  control  under the
 proposed  standards at present.   Rather than  delay promulgation of the
 proposed  standards to incorporate  an evaluation of  hot metal  desulfuri-
 zation, control of these emissions will  be considered  during  the next
 4-year review  of the  primary  and secondary emissions standards.
      Remaining ancillary operations  not directly  associated with the
 BOPF vessel  (other than hot metal  transfer and skimming)  include
 teeming,  dekishing, slag handling,  ladle maintenance,  and flux handling.
 Except for teeming, no emission  factors  are  available  to  quantify
 uncontrolled particulate matter  emissions  from these operations,
 although  low-level visible emissions  from  these operations  have  been
 observed.  . Based on a review  of  the  estimate  contained  in  the  preamble
 (that ancillary .operations contribute  about 8 percent  of  total  BOPF
 fugitive  emissions at a typical  shop),  it  is  agreed that particulate
 emissions  from these  sources  may be  greater than  previously estimated.
 However,  the lack of  quantitative  emission data,  coupled with  the
 absence of good demonstrated  control technology,  prevented the selection
 of these  operations for control at present.   Should additional data
 become available, these operations will also.be evaluated during  the
 next  4-year review of the primary and  secondary standards.
      For  teeming operations, AP-42 (Supplement 11) reported an emission
 factor of  0.07 Ib/ton of steel, applicable to both top- and bottom-
 blown  furnaces.  Based on this emission factor, uncontrolled secondary
 emissions   of a typical shop are estimated at  112 ton/yr.  Even though
 these emissions are not insignificant, observations of visible emissions
 did not indicate measurable levels at BOPF shop roof monitors.  Although
 controls are used for teeming of leaded steel, leaded steel represents
 a relatively small  percentage of total steel  production.  Application
 of these controls on the scale required to fit teeming of all  steel
produced needs further study before a decision to regulate can be
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 made.   Furthermore,  many BOPF shops  are  installing  continuous  casting
 facilities.   The  general  trend is  toward this  energy  and  labor saving
 production  step that will  reduce the amount of steel  teemed  (IV-J-1).
 For the above reasons,  teeming was not selected as  an emission source
 for .regulation at present.   However,  this operation also  will  be
 reviewed and  considered for control  during the next 4-year review  of
 the primary and secondary standards.
 2.3 BEST DEMONSTRATED  TECHNOLOGY  (BDT)
 2.3.1   Comment:   (IV-D-2)   One commenter disagreed  with the  preamble
 statement (p.  2661)  that certain operating practices  (e.g.,  clean
 scrap,  slow pouring,  careful  positioning of the hot metal ladle, and
 proper  furnace tilt  angle)  have been demonstrated only for top-blown
 furnaces.   He stated that during testing of the Republic  Steel  bottom-
 blown furnace (Q-BOP),  these  practices were used and  appeared  to
 generate few  or no fugitive emissions that escaped  the secondary
 control  system.   This control  was  achieved despite  the improper operat-
'ing condition of  the control  system  (one fan on primary hood and one
 on  secondary  hood, rather than two on secondary) during the  test.
 Consequently,  roof monitor  opacity reached a maximum  of 15 percent but
 averaged less than 10 percent over the period  of hot  metal addition.
 However,  according to the  commenter,  these conditions were not achieved
 consistently  during  the test  program.
     Response:  As the  commenter pointed out,  periods existed  during
 which the indicated  operating practices  were accompanied  by  few or no
 fugitive emissions that escaped the  secondary  control  systems.  As he
 also pointed  out,  these conditions were  not achieved  consistently.  In
 our engineering judgment,  this lack  of consistency  indicates that  the
 operating practices  mentioned by the  commenter are  not demonstrated
 for bottom-blown  furnaces.  Therefore, the operating  practices  were
 not included  as an element  of BDT  upon which the proposed standard for
 Q-BOP's  was based.   This  lack of consistency was a  contributing factor
 to  our  conclusion  that  the  Republic  Steel  System does not truly represent
 BDT for  bottom-blown  controls.  The  rationale  for withdrawal of the
 proposed Q-BOP standard is  discussed  further in response  to  comment
 2.4.4.
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 2.3.2   Comment:   (IV-D-2)   One  commenter  questioned  the  conclusion
 that performance  of roof-mounted  electrostatic  precipitators  (RMESP's)
 may  be  equivalent to or  better  than  BDT for  secondary  emission  collec-
 tion when  no  data were available  to  assess RMESP  performance.   The
 commenter  also questioned why a Japanese  RMESP  was not evaluated  to
 support the proposed standards.   This  commenter pointed  out that  a
 baghouse can  handle secondary emissions containing hard-to-precipitate
 kish particles and significant  amounts of fine  particulate emitted in
 large bursts  more efficiently than can an RMESP.  Although the  commenter
 supported  the possible RMESP waiver  for innovative technology,  he
 suggested  that the conclusion that the RMESP may  be  equivalent  to (or
 better  than)  BDT  at a lower cost  should be verified.
     Response:  Section  lll(j)  of the Clean Air Act  provides that an
 owner or operator of an  affected  facility may request  a  waiver  from
 one  or  more requirements of the standards to encourage the use  of the
 innovative control  system.  Findings that the technology has not been
 demonstrated  adequately  and that  it  has either  a  substantial likeli-
 hood of achieving greater emission reduction than required by the NSPS
 or of achieving equivalent emission  reduction at  Tower cost (including
 energy  and nonair environmental costs) are necessary for an owner or
 operator to obtain  an innovative  technology waiver for other requirements
 of the  standard.   Once a waiver has been  issued,  its terms must include:
 (1)  assurance that  the source emissions will  not prevent attainment
 and  maintenance of  national  ambient air quality standards (NAAQS's);
 (2)  assurance that  the technology will function properly; (3) a time
 limit for testing the technology  not to exceed 7 years from issuance,
4 years from startup, or until  the technology proves unworkable; and
 (4)  a restriction to that portion of the source on which the technology
 is used.  The commenter is correct in noting that no data were available
to quantify the performance, costs,  and other impacts associated with
the  use of RMESP's.  However,  as  indicated in the proposed rulemaking,
there were qualitative indications that RMESP's have the potential to
be at least as efficient as, and more cost effective than,  capture
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 hoods  ducted to  a particulate collection  device,  which  is  the  technology
 on which  the numerical standard  is  based.   Some of  this qualitative
 information  was  obtained from RMESP's  in  Japan.   Unfortunately,  the
 Japanese  companies using the  RMESP's would  not permit the  quantitative
 evaluation of their control technologies.
     The  final rule in Subpart Na applying  to visible emission opacity
 from roof monitors represents the minimum level of  control  for secondary
 emissions needed to comply and was  based  on data  taken  from plants
 with best demonstrated conventional technology.   Because there may be
 an emission  flow volume  difference  between  the discharge of an RMESP
 and the discharge of the more conventional  BDT secondary systems, it
 is not clear that RMESPs are  necessarily  equivalent to  best technology.
 Therefore, during any required case-by-case reviews, RMESP  design will
 also be considered.
     Under the terms negotiated  for any waiver granted,  provisions
 would  be  included to ensure that any RMESP  installed to comply with
 the NSPS  would be designed and operated properly.   Data collected
 during the term  of the waiver would be used to verify RMESP performance
•and costs.   Should the performance  and costs be demonstrated as  equivalent
 to or  better than BDT, the inclusion of provisions  specific to RMESP's
 would  be  considered during the next 4-year  review of Subpart Na.
 2.3.3  Comment:   (IV-D-1 and  IV-D-3)  Two commenters pointed out that,
 while  the proposed standards  do  not require the use of  a specific
 technology to meet the proposed  emission  limits,  a  steel producer
 could  experience  difficulties  in permit approval  if the  producer
 desired to implement a technology not examined or discussed in the
 preamble  or  BID  for the  proposed or promulgated rule.   In this regard,
 both commenters pointed  to fume  suppression, a relatively new  technol-
 ogy, which could  provide the  potential for  eliminating  or reducing the
 need for  particulate capture  techniques.  One commenter  stated that
 the cost  to  implement and operate this technology can be substantially
 less than other control  alternatives, with  fume suppression providing
 an equivalent performance.  Accordingly, the commenters  recommended
 that this technology be  examined as a viable alternative control
 technique.
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      Response:   Before responding to  the commenter's  point,  it is
 important to  note  that permit approval  is not required  for NSPS's.
 Any permit that would  be  required would be for State  or local  agencies.
 It  is agreed  that  in such cases  the source may need to  provide a basis
 for concluding  that compliance is probable.   Data  regarding  fume
 suppression were not available when Volume I  of the BID was  being
 prepared.   Since proposal,  however, new information and data have been
 obtained  to support further the  conclusion that fume  suppression
 systems may provide, at a lower  cost, performance  equivalent to that
 of  other  control alternatives  (IV-B-4).   Because the  standards of
 performance for hot metal  transfer stations are expressed  as numerical
 emission  limits, an owner or operator may choose to install  a  fume
 suppression system to  control  hot metal  transfer emissions so  long as
 it  can achieve  compliance with the numerical  limit.
      Suppression techniques  reduce iron  oxide  fuming  above molten
 metal or  slag baths by inhibiting oxidation of the iron  at the surface
 of  the bath.  Oxidation is  inhibited by  blanketing the  bath  surface
 with  flame, steam, wet sand, or wet slag.  To  date, these techniques
 have  been  applied experimentally  to:   (1)  blast furnace  iron tapping,
 (2) blast  furnace slag tapping, (3) open  hearth tapping, (4) electric
 furnace tapping, (5) hot  metal transfer,  (6) BOPF charging,  (7) BOPF
 tapping, and (8) BOPF  lance  hole  emissions.
      Preliminary data  quantifying  the performance of  flame suppression
 on  a  BOPF  hot metal transfer station at U.S. Steel's Gary plant indicate
 that  opacity is reduced significantly with the use of flame suppression.
 These data  are provided in Table 2-2.   Thus, while these techniques
 are not yet demonstrated  for other portions of the BOPF production
 cycle, it appears that flame suppression  (one of the several  fume
 suppression techniques) is capable of achieving emission reduction at
 least equal to requirements of the proposed regulation during hot
metal transfer.
     Moreover, because flame suppression eliminates the need  for
capture and control devices, emission  reductions may be achieved at
costs significantly below those of the BDT on which the standards  are
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      TABLE 2-2.  HOT METAL TRANSFER FLAME SUPPRESSION EVALUATION
Number of 15-second
readings >20 percent
opacity observed per
hot metal transfer
0
1 to 5
6 to 10
11 to 15
16 to 20
>20
Percentage
No. 1
Without
flame sup-
pression
54.3
11.4
14.3
11.4
5.7
2.9
of total hot metal transfers observed
BOPF shop
With
flame supr
pression
96.0
4.0
0
0
0
0
No. 2 BOPF shop
Without
flame sup-
pression
68.3
15.1
8.6
4.3
2.6
1.1
With
flame sup-;
pression
89.2
5.6
5.2
0
0
0
 Based on 70 hot metal
""Based on 50 hot metal
'Based on 65 hot metal
 Based on 85 hot metal
transfers observed.
transfers observed.
transfers observed.
transfers observed.
based.  The cost effectiveness of fume suppression applied to hot
metal transfer emissions is estimated at $633/ton of particulate
matter removed.  Depending on the control scenario applied, this can
be compared to a cost effectiveness of $l,755/ton for a baghouse
collecting furnace secondary and hot metal transfer emissions and
$3,104-ton for a baghouse collecting only hot metal transfer emissions.
     As described in the response to comment 2.3.2, for the purposes
of this NSPS, an innovative technology waiver may be granted to an
owner or operator desiring to install a fume suppression system to
meet the standards.
     Under the negotiated terms of an innovative technology waiver,
the owner or operator would be granted an extended time period to meet
the visible emission standard.  Fume suppression systems are exempt
from the mass and opacity emission limits for secondary emission
control devices because use of the fume suppression technique eliminates
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 the need for other capture and collection equipment.   Provisions would
 be included in any waiver agreement to ensure that a fume suppression
 system installed to meet the NSPS would be designed and operated
 properly.   Data collected during the term of the waiver would be used
 to document the performance and costs of fume suppression for particulate
 emission control.   Should the performance and costs be equivalent to
 or better than BDT, the inclusion of provisions specific to fume
 suppression systems may be considered during the next 4-year review of
 Subpart Na.
      The final  standards also contain a definition for fume suppression
 systems.   A fume suppression system is defined as "the equipment
 comprising any system used to inhibit the generation  of emissions from
 steelmaking facilities by means  of an inert gas,  flame,  or steam blanket
 applied to the  surface of molten iron or steel."
 2.3.4  Comment:   (IV-D-2)  One commenter questioned the  estimated
 capture efficiency of 90 percent or more for auxiliary hooding and the
 application  of  this estimated capture efficiency  to bottom-blown
 furnaces.   He  referred to tests  conducted on the  Republic  Steel  Q-BOP,
 stating that:   (1)  this  furnace  did not have an auxiliary  hood for
 tapping, and the secondary control  system demonstrated much  less  than
 90 percent capture  for tapping emissions;  (2)  at  least seven mechanical
 failure incidents  occurred during  the test  (bell  damper problems);  and
 (3) a capture effectiveness  of 90  percent or more was  demonstrated
 on occasion  (emphasis  added  by commenter)  for  hot metal addition
 emissions.   This commenter indicated  that the  preamble incorrectly
 implied (p.  2661) that 90  percent  capture had  been  demonstrated on  a
 continual  basis at the time  of the test program.
      Response:   The commenter's concern that 90 percent capture is  not
 continually  attained rests on his observations during testing at the
 Republic Steel  Q-BOP.  He  correctly points out that the Republic
 facility has no tapping hood.
     The last two sentences of the Federal Register notice paragraph
 to which the commenter refers are, "An enclosure with hoods located
over the charging and tapping areas may achieve a capture effectiveness
of 90 percent or better.  This control system has been demonstrated
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for both top and bottom blown furnaces" (emphasis added).  The
first sentence is meant to imply that there is a possibility rather
than a probability of 90 percent capture given sufficient hooding.
Because the Republic facility has no tapping hood, a capture efficiency
of less than 90 percent would be expected.  The last sentence of the
paragraph is meant as a summarizing sentence for the entire paragraph
rather than as a continuation of the preceding sentence.  The selection
of the Republic system as BDT for bottom-blown furnaces is further
discussed in the response to comment 2.4.4.
2.3.5  Comment:  (IV-D-2)  One commenter, in referring to the preamble
discussion of the capture efficiency of building evacuation systems
(p. 2661), asked if the system discussed (the roof monitor evacuation
system with baghouse controls at the No. 2 BOPF shop of Inland Steel,
East Chicago) handles only a portion of the total shop emissions
(i.e., those generated by the most recent furnace installation) or if
it handles emissions from the entire building.
     Response:  The capture system in question is a partial building
evacuation system applied only to the furnace charging aisle.  A
curtain wall is installed between the charging aisle and the furnace
aisle to prevent substantial movement of charging emissions to the
furnace aisle.  The system is used in conjunction with local hoods
within the furnace enclosure.  Visual observation shows that the
evacuation rate for this partial building evacuation system (130 acms
or 275,000 acfm) is less than is required to prevent leakage from the
enclosed portion of the building even with the assistance of the local
hoods.  For this reason, the Inland facility was not considered BDT
for secondary emission control.
2.4  NUMERICAL EMISSION LIMITS
2.4.1  Comment (IV-D-2)  One commenter asserted that the proposed mass
emission standard for secondary emission collection devices (0.010 gr/
dscf) did not reflect the performance of baghouses, which was selected
as BDT for this application.  The commenter argued that a properly
designed, operated, and maintained baghouse controlling emissions from
hot metal transfer, skimming, and other operations can achieve an
outlet emission rate of 0.005 gr/dscf.

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      Response:   The  numerical  emission  limit of 0.010  gr/dscf proposed
 for secondary emission  collection  devices  is based on  the  data available
 at  proposal.   The  data  base  for the  emission limit,  as proposed,
 includes  data from hot  metal transfer,  partial  building evacuation  for
 BOPF's, and  full-cycle  data  for electric arc furnaces  (EAF's).  Other
 operations that  generate  secondary BOPF emissions  are  not  included  in
 the data  base.   While the commenter  correctly states that  certain
 operations can be  controlled to achieve an  emission  rate of  0.005 gr/
 dscf, control  of all pertinent operations has not  been demonstrated
 adequately at that level.
      The  data supporting  the proposed standard  do  not  support a lower
 limit.  It is agreed that new  data,  coupled with the transfer of
 technology from  EAF's,  might support the lower  limit recommended by
 the commenter.   However,  without the benefit of public comment and
 because it is  hot  clear whether other data  reflect technology different
 from the  data on which  the 0.010-gr/dscf limit  is based, the  final
 rules do  not  revise the standard for secondary  emission  collection.
 devices.  Revising the  standard to reflect  tHe  higher  performance
 level will be considered  during the  next 4-year review of  Subparts  N
 and Na.
 2.4.2  Comment:  (IV-D-2)  One  commenter believes the  numerical emissio'n
 limit for the proposed  revision  to the  existing particulate standard
 for a closed  hood  furnace primary control device outlet  should  not  be
 raised to 68 mg/dscm (0.030 gr/dscf).   The  commenter stated that two
 of  three plants tested  emitted  particulates  at  or below  the current
 standard of 50 mg/dscm  (0.022 gr/dscf)  and  one  plant was found  to be
 just above the standard at 55 mg/dscm (0.024 gr/dscf).   The commenter
 asked why the proposed  standard was  raised  to 68 mg/dscm (0.030 gr/dscm)
when the majority  of the plants tested  (two out of three) met the
existing standard.
     Response:  Selection of numerical  emission limits  must take into
account variability of control  system performance and performance
measurements.  Without accounting for this  variability, the plants
using BDT, even those used as the basis  for the standard, could fre-
quently be found to be violating the standard.  One means of taking
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this variability into account is to use a statistical analysis approach.
Statistical analysis was used to aid in the selection of the proposed
revised standard, 68 mg/dscm (0.030 gr/dscf).   The means and standard
deviations of the three test averages were computed for comparison,
after which an upper 95-percent prediction limit was computed based on
the standard deviation computed for the 15 individual test runs.   The
numerical emission limit selected, 68 mg/dscm, was just above the
upper 95-percent prediction limit, 66 mg/dscm.  Although the proposed
numerical limit is less stringent than the original, it nevertheless
requires application of BDT.
     Data presented in Table 4-12 of the BID suggest that a lower
concentration limit for open hood furnaces may be possible.  These
data show performance levels better than performance measured during
testing to support the existing NSPS limit of 50 mg/dscm (0.022 gr/dscf).
Determination of the equipment design, operating criteria, and process
variables responsible for producing lower emission concentrations from
the open hood furnaces will be examined during the next 4-year NSPS
review for consideration of a change in the concentration limit.'
2.4.3  Comment:  (IV-D-1)  One commenter pointed to unique problems
with Q-BOP's (bottom-blown furnaces) when certain grades of metallurgical
steel are made.  Oxygen blowing as the vessel  is turned down is required
for these types of steel, which results in emissions even greater than
during nitrogen blowing during typical vessel  turndown.   For this
reason, the commenter recommended that this issue be addressed and
that increased opacity limits for Q-BOP's be allowed when metallurgical
grades of steel that require oxygen blowing during vessel turndown are
made.
     Response:  The issue raised by the commenter, although not specif-
ically mentioned in the BID, was addressed during testing of the
Republic Steel Q-BOP system.  Metallurgical steels with oxygen blowing
during turndown were made during some of the heats made during the
test periods.  The opacity readings from these heats have been sum-
marized in the BID and have been considered part of the data base used
to propose the opacity limit for bottom-blown vessels.   The impact of
oxygen blowing during turndown was adequately considered during analysis
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 of this data base.   The Republic system as the basis of the proposed
 Q-BOP standard is further discussed in the response to the following
 comment.
 2.4.4  Comment:   (IV-D-2)  One commenter criticized the selection of
 the proposed opacity limits for Q-BOP (bottom-blown) vessels.   This
 commenter stated that the proposed 60-percent opacity limit does not
 reflect BDT because the Republic Steel  Q-BOP system (upon which the
 proposed emission limit is based) is  inadequate for the following
 reasons:   (1) failure of the system to achieve 90 percent capture
 effectiveness consistently during the testing program because  of
 secondary emission  control system mechanical  (bell  damper) failures;
 (2) poor design;  and (3) poor maintenance.   Rather,  he recommended a
 bottom-blown regulatory alternative consisting of an enclosure with
 local  hot metal  addition (HMA) and tapping hoods  exhausted to  a baghouse
 (or equivalent device)  that can handle  600,000 acfm  or the gas volumes
 handled by the Bethlehem and J&L plants.
      Response:   The opacity limit proposed for bottom-blown vessels
 was consistent with data for bottom-blown  furnaces that were-available
 at  proposal.   The effect of the commenter1s  recommendation would  be the
 establishment of an emission limit at a level  that has  not been observed
 in  practice  for bottom-blown furnaces.   It is  agreed  that  the  performance
 of  controls  on other sources,  such as top-blown furnaces,  suggests
 that better  performance  should be  achievable  for  bottom-blown  furnaces
 and raises doubt as  to whether the proposed  limits reflect the  perform-
 ance of BDT.   The commenter  also  correctly  implied that capture and
 control of emissions  from  these  vessels have not  been demonstrated  at
 a level consistent with  top-blown  vessels.  A more stringent limit
 based on transfer of  technology was not considered warranted in the
 case of bottom-blown  vessels because of the wide  range of  conditions
 under which the vessels  operate and the correspondingly wide range of
 emissions from the vessels (see the preceding comment and  response as
 an  example).
     Based on this comment and further review, it has been determined
that better control  will likely become available before the next
4-year review of the primary and secondary standards, and that the
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proposed opacity standard, if promulgated, would probably not reflect
BDT.  In particular, it should be noted that revised State opacity
regulations adopted pursuant to the requirements of 40 CFR Part 52 are
much more stringent than the proposed standard.  Because of these
findings, the proposed roof-monitor opacity limit for bottom-blown
vessels is being withdrawn from the final rules.
     The requirement for limiting the opacity of visible emissions
produced by hot metal transfer and skimming in bottom-blown furnace
shops, however, is being retained.  There are no significant process
differences between hot metal transfer and skimming in bottom-blown
furnace shops as opposed to top-blown furnace shops.  Likewise,
equipment used to perform these processes is not necessarily different
in bottom-blown versus top-blown shops.   Therefore, there is no reason
to believe that any significant difference should exist in emission
potential, either controlled or uncontrolled.   For the above reasons,
the roof monitor opacity limit for hot metal transfer and skimming in
top-blown furnace shops is extended to apply to hot metal transfer and
skimming in bottom-blown furnace shops.   The .provisions of Subpart Na,
§60.145a, allow the owner or operator of an affected facility to
suspend shop operations not subject to Subpart Na during compliance
testing.   These provisions are a means of avoiding interference from
bottom-blown furnace emissions during compliance testing of hot metal
transfer and skimming operations.   By similar reasoning, the proposed
concentration and opacity standards for secondary emission collection
devices in bottom-blown furnace shops also are retained.
2.5  VISIBLE EMISSION STANDARDS
2.5.1  Comment:  (IV-D-3, IV-D-4)   Two commenters opposed a provision
of the proposed standards [at §60.144a(b)(3)]  that changes the way
Method 9 visible emission data from BOPF shops are analyzed.   The
commenters noted that Method 9 requires  an opacity value to consist of
the average of 24 consecutive visible emission observations taken at
15-second intervals and that the proposed standards alter this
requirement to produce an opacity value  based on an average of 12
consecutive visible emission observations.
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      Both commenters contended that the public was not afforded suffi-
 cient opportunity to comment on the proposed changes.   One commenter
 concluded that the changes  constitute ad hoc rulemaking and noted that
 such procedures have been invalidated by Conner Hanna  Coke Corp.  v.
 Costle,  464 F.  Supp.  1295 (W.D.N.Y.  1979).   The commenter believes
 that "The 'Conner Hanna1  Court decision clearly demonstrates that the
 test method used to evaluate compliance with a regulation is as impor-
 tant as  the regulation  itself.   Merely specifying the  test method is
 not  enough when the accuracy and precision  of the method are unknown
 in the prescribed application."
      The commenters also  believe that the proposed 3-minute average
 contradicts previously  articulated  policy about how Method 9 should  be
 used.  In support of this,  one  commenter noted that "In previous
 instances,  EPA  has suggested that there is  no known basis  for altering
 the  procedures  and methodology  established  under Method 9.   For example,
 on November 24,  1982, while  reconsidering the Illinois  State implemen-
 tation plan (SIP),  the  Administrator  stated:
     '                                               '               •
      'There is  no  means,  using Method 9,  to  account for plumes,
      less  than  6 minutes  in  duration  (noncontiguous).    There is
      also  no means,  using the averaging techniques  of Method 9,
      to  account  for exemption periods  other  than  6  minutes  or for
      aggregation of any duration.   (47  FR 5300,  5302).'"
      The  second  commenter noted  that  "In  the  past,  EPA  has  recognized
 that  [Method 9] cannot  be used for  intermittent  non-stack  sources."
      Response:   Examining first  the question  of whether  the  public has
 had opportunity to  comment on the proposed changes, we  conclude that
 both  the general public and  steelmaking  facilities with  BOPF's have
 had ample opportunity to participate  in and comment on the proposed
 changes.   Prior to  proposal, representatives of public  interest groups
 and steel companies were provided several opportunities to comment on
 the 3-minute average.   For example,  the 3-minute average was discussed
 at the National Air Pollution Control Techniques Advisory Committee
 (NAPCTAC) meetings of December 2-3,  1980, and September 22-23, 1981
 (II-C-24, II-E-23).  The 3-minute average was also discussed at two
meetings  held with representatives of the American Iron and Steel
 Institute (AISI) November 12, 1980 (II-E-15), and September 17,  1981

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(II-E-25).  Review drafts were specifically provided to AISI for
distribution to member companies September 4, 1981 (II-C-40),  and
November 12, 1981 (II-C-42).   In no case were written comments provided
by industry representatives or other interested parties prior to
proposal.  At proposal, the preamble to the regulations discussed
testing and data reduction procedures used to establish the visible
emission standards and the procedures that would be followed to deter-
mine compliance (48 FR 2662).   Comments received on these procedures
are being taken into account in this rulemaking.
     In addition to the information provided in the forums noted
above, an analysis of the effects of the proposed changes on the
scientific reliability of Method 9 was included in the docket that
accompanied the proposed rule (II-B-92).  The information in this
analysis demonstrates that the precision and accuracy of the proposed
changes to the Method 9 data reduction procedure for visible emission
observations of BOPF's are equivalent to the precision and accuracy in
the current Method.  (This analysis is discussed in detail in the
response to comment 2.5-2.)  Moreover, no new data or information on
the visible emission standards that contradicts the findings of our
analysis was included with the public comments.  Therefore, the public
has been provided sufficient opportunity to comment on the proposed
performance testing and data analysis procedures.
     We note that in citing the Illinois SIP reconsideration,  the
commenter suggested that statements about the use of Method 9 in its
present form should limit how the Method might be modified.  This
suggestion, however, is without merit.  Rather, the validity of modifi-
cations to standards and test methods (and the relationship between
these) set forth in 40 CFR 60 must be evaluated and must be supported
on their own merits.
     As to the question of whether Reference Method 9 can be used for
intermittent nonstack sources, it should be noted that since its
promulgation December 23, 1971 (36 FR 24895), Method 9 has been amended
to observe visible emissions from both control device exhaust stacks
and nonstack sources (39 FR 39872, November 12, 1974).  (See,  for
example, Subparts AA and BB.)  Indeed, the Method, at paragraph 2.1,
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 specifically includes  procedures  to  be  used  in  determining visible
 emissions  from  nonstack sources such as roof monitors.   Often,  both
 control  devices and  nonstack  sources such  as roof  monitors intermittently
 emit  plumes  of  varying opacity; i.e., visible emissions  vary with
 process  or control device  operation  and are  observed  only  during part
 of  the time  the emission source is operating.   Reference Method 9 can
 be  applied accurately  to both categories of  emission  points by  following
 the procedures  of paragraph 2.1 and  by  recording visible emission
 observations  of zero percent opacity when  no visible  emissions  are
 evident.
      The passage from  Method 9 cited by the  Court  in  Conner Hanna does
 not state  that  Method  9  is inappropriate for characterizing visible
 emissions  from  all points  of intermittent  emissions:
      EPA recognizes that certain  types  of  opacity  violations that
      are intermittent  in nature require a  different approach in
      applying the opacity  standards. ...    (39 FR 39873)
 The passage cited by the Court indicates that Method  9 (with the
 6-minute averaging technique) may hot characterize the performance of
 capture or control technologies adequately in certain cases.  This can
 be  illustrated  by the  hypothetical example of a source that exhibits
 zero  opacity for 23 out  of 24 readings and 25 percent on the 24th
 reading.   On a  6-minute  average basis, the opacity would be calculated
 as 1  percent.   On a 15-second basis, opacity would simply be 23 periods
 of zero and 1 period of  25 percent.   It is  obvious that this latter
 method of presenting the visible emission data is much more descriptive
 of the emission  characteristics in this case than is the 6-minute
 1-percent opacity average.   In the broader context, this hypothetical
 example illustrates how  shorter averaging periods more accurately
 reflect the character of short-duration plumes.   (It also shows how
 general  opacity  standards that are commonly used in SIP's do not
account for plumes of short duration.)  For this reason,  a shorter
averaging time and a higher numerical visible emission standard were
proposed for BOPF's.   A 6-minute averaging  period could have been
selected to analyze BOPF visible emission data.   If this  option had
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been selected and implemented, the numerical level of the standard
would have been about one-half the numerical level proposed in conjunc-
tion with the 3-minute averaging period.  However, BOPF secondary
emissions are typically of short duration, and a 3-minute averaging
period more closely characterizes the performance of the capture
systems used to control the emissions than a 6-minute averaging period.
     Finally, it is agreed that the test method used to determine
compliance with a standard is very important in establishing the
stringency or effect of a standard.  For this reason, the basis for
the standard, including not only the data base but also both the test
method used to develop the data base and the test method used for
compliance, must be considered in establishing a standard.  This is
discussed further in response to comment 2.5.2.
     In conclusion, it is noteworthy that this proposed rulemaking
does not affect Method 9 data reduction procedures or application of
Method 9 to all sources regulated in 40 CFR Part 60.   Rather, it only
establishes procedures for BOPF's that commence construction, modifica-
tion, or reconstruction after January 20, 1983.  Use of a 3-min,ute
average was proposed in paragraph 2.5, "lest Methods and Procedures"
in Subpart Na, rather than as amendments to Reference Method 9.   Ihis
was done because 3-minute average opacity values are considered appro-
priate for and are intended to be applicable only for BOPF shop emissions.
In this way, Method 9 as it applies to other sources is not affected
by this ralemaking.  Ihis approach is consistent with the intended use
of the test methods in Appendix A (40 CFR Part 60).   Ihe intent is
detailed in the introduction to Appendix A, which states, in part:
     Within each standard of performance, a section titled 'lest
     Methods and Procedures'  is provided to (1) identify the test
     methods applicable to the facility subject to the respective
     standard and (2) identify any special instructions or condi-
     tions to be followed when applying a method to the respective
     facility.  Such instructions . .  .  are to be used either in
     addition to, or as a substitute for, procedures in a reference
     method.
Iherefore, it is appropriate to alter—after analysis and public
comment—the data reduction procedures for BOPF visible emission
observations within the provisions of Subpart Na.

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 2:5.2  Comment:   (IV-D-1,  IV-D-3,  IV-D-4,  and IV-D-5)  Several  commenters
 questioned the scientific  reliability of the proposed 3-minute  averages
 for Reference Method 9 opacity computations of visible emissions from
 BOPF's.   The commenters contended  that the modified averaging procedure
 will  produce average opacity values  that are less  accurate and  more
 subject to error than the  6-minute opacity values.   The commenters
 stated that the  proposed secondary standards require the improper use
 of Reference Method 9 for  observing  roof monitor visible emissions
 because the method  was promulgated originally for  observation of
 stacks,  with specified data  reduction procedures for 6-minute averages.
 The commenters stated that quantitative conclusions regarding the
 accuracy of the  method were  valid  only for emissions from stacks.   One
 commenter also maintained  that modifications to  Method 9 should be
 thoroughly evaluated to determine  the accuracy and  precision  of any
 deviations and recommended that Method 9,  unmodified,  be used for the
 proposed regulation or that  the proposed roof monitor  opacity standard
 be  deleted until  an appropriate method is  developed.   One commenter
 further  asserted  that .the  proposed changes  are not  supported  by any
 analysis  of the effects  of the  changes  on  the  scientific reliability
 of  Method 9.
      Response:  We  share the commenters1 concerns that  knowledge  of
 the precision and accuracy of  a test  method—and consideration  of
 these  factors for the public record—is  important in developing and
 enforcing standards.   Prior to  responding to these concerns,  it  is
 appropriate  to review the  general procedure  followed to  establish a
 standard  of  performance and to  understand the role of the test method
 to establish and determine compliance with the standard.  Typically, a
 standard  is  expressed as a numerical  emission limit that quantifies
 the performance of BDT for emission control.  A data base is gathered
 to establish an emission limit that is achievable for the emission
 source being regulated.  The data base is obtained with either an
existing or new test method that has  been devised for the pollutant
and source being regulated.  If the method used to  develop the data
base differs from the method that would be used to  determine compliance,
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the mathematical relationship between these methods must be known.   In
either case, the test method is proposed and promulgated according to
the procedures outlined in §307(d) of the Clean Air Act as amended and
is found either in Appendix A or in the subparts of 40 CFR Part 60.
In the proposed and final standards, the accuracy and precision of the
test method are documented and considered carefully.
     When the visible emission standards were developed for BOPF's,  a
large number of visible emission observations were gathered according
to the procedures of Reference Method 9.  These data, which consist of
more than 100 hours of observations, indicate that plumes from the
roof monitors of BOPF shops are of short duration and that the perform-
ance of BDT for controlling these emissions is best characterized with
an average opacity value based on a shorter, 3-minute averaging period
instead of the 6-minute averaging period specified in the data reduction
procedures contained in paragraph 2.5 of the reference method.
     Therefore, a visible emission standard was proposed that would be
based on the BOPF visible emission data base and on average opacity
values calculated from 12 consecutive 15-second visible emission
observations recorded by following the procedures of Reference Method 9.
The proposed and final performance test procedures are also based on
observing and recording visible emissions with Reference Method 9 and
on calculating a 3-minute opacity average from the visible emission
data.
     Before 3-minute rather than 6-minute averages were proposed, the
question of whether 3-minute averages are less accurate or precise
than 6-minute averages was addressed.  (Note that the accuracy and
precision of 6-minute averages have been established and are not an
issue here.)  This involved analyzing and comparing the frequency of
occurrence of differences between Method 9 observations (observer
mean) and mean values calculated from transmissometer readings (instru-
ment mean) for both 3- and 6-minute averaging periods.  This analysis,
which was included in the docket prior to proposal (II-B-92), is based
on a July 1976 report that also was included in the docket prior to
proposal (II-A-22).  The results of this analysis are summarized in
Table 2-3.
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   TABLE 2-3.   OBSERVER ERROR FOR 3-MINUTE AND  6-MINUTE  OPACITY AVERAGING9
                       (percent of total  observations)
Source
Smoke generator,
3-minute average
Opacity range , %
0-5 5-10 10-15
36.5 1.9 0.0
6-minute average
Opacity range, %
0-5 5-10 10 -
35.3 0.8 0.0


15

  black  smoke
 Smoke generator,      36.0     8.0      0.3
  white  smoke
 Riverbend Steam       41.7     5.2      1.0
  Station
31.8
43.8
7.1
4.2
0.0
1.0
 Observer error is defined as deviation of observed average opacity from
 reference  (transmissometer) average opacity.
SOURCE:  "Examining the Properties of Qualified Observer Opacity Readings
         Averaged over Intervals of Less than Six Minutes," Research
         Triangle Institute, July 1976 (II-A-22).

     The results are reported as the percentage of the total number of
measurements that fall within a particular range of observer error.
For example, 36.5 percent of the total number of 3-minute averages
calculated  for the smoke generator black smoke had an observer error
of between  0 and 5 percent opacity.   Note that only positive errors
are reported in the table.  Examination of this table reveals that the
distribution of errors for 3-minute averaging is about the same as for
6-minute averaging (e.g., for generator black smoke, 36.5 percent of
the calculated 3-minute averages had an observer error of 0 to 5 percent
opacity as compared to 35.3 percent of the calculated 6-minute averages).
Thus, the average opacities calculated on a 3-minute basis are no more
subject to error than the average opacities calculated on a 6-minute
basis.
     With regard to the applicability of Method 9 to plumes from both
stacks and roof monitors, a review of opacity theory demonstrates that
quantitative conclusions  about the accuracy and precision are equally
valid for each.
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     The major factors influencing plume opacity are:  particle charac-
teristics (particle size distribution, particle density, and refractive
index), particulate concentration, the background against which the
emissions are viewed, the observer's position relative to the sun, and
the light path length through the emission plume.  Particle character-
istics and particulate concentration are determined by the process
operation and the emission control technology.  In the steel industry,
plumes are released at elevated points such as stacks and roof monitors.
As a result, the background for reading the opacity of visible emissions
is the same for both types of sources, generally consisting of sky,
horizon, or other structures.  Thus, the ability to read opacity of
visible emissions from roof monitors compared to the ability to read
visible emissions from stacks is not influenced by background.
     While the geometry of stacks and roof monitors does differ,
Reference Method 9 explicitly accounts for opacity readings from roof
monitors.  Stacks are generally circular and, as a result, the path
length through the plume is essentially the same in all directions.
Roof monitors tend to be rectangular with a long and short dimension.
The light path length through the plume is different depending on
whether the observer sights along the long dimension or the short
dimension.  When the opacity of visible emissions from roof monitors
is read, paragraph 2.1 of Reference Method 9 specifically requires
that observations be taken approximately perpendicular to the long
dimension of the roof monitor (i.e., across the short dimension of the
plume), which ensures that observed opacity is minimized.  When the
visible emission standards for BOPF's were developed, visible emission
observations were taken from existing furnace shops with typical roof
monitor designs.  We have no data or other information that indicates
that future roof monitor designs would be modified to cause plume path
length, and thus observed opacity, to increase.  Thus, the effect of
path length on opacity was taken into account during development of
the standards, and paragraph 2.1 of Reference Method 9 ensures that
compliance with the standards is determined by reading plumes across
the shorter path length.
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      The position of the visible emission observer with respect to the
 sun and the plume does affect perceived opacity due to the light-
 scattering effects of plumes.   However, this light-scattering inter-
 ference is nullified as the observer is positioned with his back to
 the sun as described in paragraph 2.1 of the Reference Method.   This
 paragraph provides explicit instructions that position the observer
 with respect to both stacks and rectangular openings such as roof
 monitors.   Thus,  the effect of position on opacity is taken into
 account during development of visible emission standards.
      The ability  to read the opacity of visible emissions,  therefore,
 does not depend on whether these emissions are released from stacks or
 roof monitors.   Reference Method 9  is as applicable to plumes  from
 roof monitors  as  it is to plumes from stacks.
      After proposal  of Subpart Na,  statistical  analyses of  visible
 emission observations  recently taken from roof monitors and stacks
 were performed to  validate this  conclusion further.   These  analyses
 are  summarized in  a memorandum entitled "Opacity Error for  Different
 Averaging  Times" -(IV-B-6),  which reports  the  results  of statistical
 analyses of visible  emissions  from  fugitive emission' sources.  The
 fugitive emission  data were  obtained mostly from iron  and steel  sources
 with BOPF  shops and  roof  monitors being major  contributors  to the  data
 base.
      One statistical analysis  examined  the precision of  observations
 of the opacity of  a  fugitive emission plume made simultaneously  by two
 visible  emission observers.  For average  opacity values  calculated
 with  a 6-minute averaging period, the standard deviation was 2.1
 percent  opacity with 93 percent of the  runs having a difference between
 observer readings  less than or equal to 7.5 percent opacity.  For
 average  opacity values calculated with a 3-minute averaging period,
the  standard deviation was essentially the same--2.4 percent opacity
with 92 percent of the runs having a difference between observer
readings less than or equal to 7.5 percent opacity.  This analysis of
visible emission observations of fugitive emissions therefore supports
the conclusion that between-observer precision is the same for average
opacity values calculated with 3- and 6-minute averaging periods.
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     Table 2-4, taken from the same memorandum, can be used to compare
the between-observer precision of fugitive emission observations with
that of stack emission observations.  The stack standard deviations
range from 4.3 to 9.8 percent for 3- and 6-minute averages compared to
the 2.1 percent and 2.4 percent reported above for the fugitive sources.
Thus, it is concluded that the variability between observers in reading
opacity from roof monitors is similar to that between observers reading
opacity from stacks.
             TABLE 2-4.  STANDARD DEVIATION OF ERROR (BETWEEN-
             OBSERVER PRECISION) FOR DIFFERENT AVERAGING TIMES
                       (BY LOCATION AND SMOKE COLOR)
Error standard deviation (percent opacity)
Averagi ng
time
6 minutes
3 minutes'
Riverbend3
White
5.0
5.1
Florida lb
Black
6.7
6.8
White
6.5
6:8
Florida 2C
Black
9.3
9.8
White
6.4
7.0
RTPd
Black
4.3
4.7
White
5.9
6.2
 Fossil-fuel-fired electric utility.
 Smoke generator—continuous plume.
°Smoke generator—slowly changing plume.
 Smoke generator—rapidly changing plume.
SOURCE:  "Memorandum, P. Piserchia and J. Crowder, Research Triangle
         Institute, to K. Foster and B. Burton, EPA:SSCD, September 8,
         1983, Opacity Error for Different Averaging Times.  (IV-B-6).

     In summary then, analyses performed both before and after proposal
of the visible emission standard demonstrate the scientific reliability
of the 3-minute averageing technique.  These analyses show that average
opacities calculated on a 3-minute basis are no more subject to error
than opacities calculated on a 6-minute basis.   Therefore, the 3-minute
averaging technique is retained in the final standards.
2.5.3  Comment:  (IV-D-1 and IV-D-4)  Two commenters recommended the
inclusion of alternative mass emission limits in the proposed standard
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 for roof monitors as allowed under 40 CFR 60.ll(e).   One commenter
 stated that a recently published procedure would allow measurement of
 mass particulate emissions  from roof monitors.   It was recommended
 that if process  fugitive emissions fail  to meet visible emission
 limits, the source should be allowed, as an alternative,  to  comply
 with measured mass emission rate estimates on which  the visible  emission
 limit is based.   However, the second commenter  pointed out that  the
 option available under 40 CFR 60.11(e)  is not available to BOPF  shop
 roof emissions because the  standards do  not contain  mass  emission
 limits or a means for allowing the exemption.
      This commenter believes that the need for  such  an exemption is
 recognized  by the EPA:
      In the preamble of the proposal  (p.  2666),  EPA  states that  "Because
      of wide differences  in operating procedures,  such as the  length
      of the steel  production cycle,  control  technologies, vessel
      capacities,  and other  operating parameters  between BOPF shops, a
      single emission rate that is  uniformly applicable to the  industry
      or a specific  type of  vessel  is  not practicable."  This same
      difference  applies to  visible  emissions and highlights the  need
      for alternative limits.                       .
      Response:   Measurements  of  mass  emission rates  from roof monitors
 have  been performed  and reported in published technical literature  on
 several  occasions.   However,  research to  verify  the  accuracy and
 precision of  a test  method  based on this  concept would  be necessary
 and costly.   In  contrast, as  discussed in  the response  to comment
 2.5.2,  the  use of Reference Method 9 to  determine the  opacity of
 fugitive  particulate matter emissions is  accurate, reliable,  and
 relatively  simple for ensuring not only  the installation of BDT, but
 also  the  proper operation and maintenance of BDT.
      Turning  now to  the comment  about alternative opacity provisions
 of §60.11(e), the commenter is correct in noting that they do not
 apply to  visible emission standards for BOPF's.   In this instance and
 similar instances in other NSPS's, the standard of performance is
expressed in terms of opacity without an accompanying mass emission
standard.  In these instances, the visible emission standard  is adequate
to ensure that BDT is installed and properly operated and maintained.
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Section 60.11(e) applies to, and was intended to cover, situations
where both mass and visible emission standards are needed to charac-
terize the performance of BDT.  In these situations, the mass emission
standards are, in effect, the primary standards used to quantify the
performance of BDT.  The visible emission standards in these situations
are established to provide a timely and inexpensive procedure to
ensure that BDT is properly operated and maintained.  Thus, in these
situations, visible emission standards are established at a numerical
level that is no more stringent than their associated mass emission
standards.  Section 60.11(e) was established to achieve this intent by
providing a means through which a source may obtain a higher ad hoc
visible emission standard when the source demonstrates compliance with
the mass emission standard but is not in compliance with the visible
emission standard.
     In summary, the visible emission standards for BOPF's are adequate
to reflect performance of BDT.  Thus, for these standards—as with
other single performance standards (e.g., S02, NO )--there is no basis
                                                 }\
for allowing case-byrcase relaxations of the standards.
2.5.4  Comment:  (IV-D-2)  One commenter suggested that visible emission
data presented under "Emission Testing" for Bethlehem Steel Corporation,
Kaiser Steel Company, and J&L Steel Corporation may be misleadingly
high because of the contributions from ancillary operations.
     Response:  The purpose of the roof monitor visible emissions
standard is to ensure proper operation and maintenance of devices used
to capture fugitive emissions from charging, tapping, hot metal transfer,
hot metal skimming, and furnace operations.  The data collected in
support of the proposed standards were based on combined emissions
escaping capture from the above sources and ancillary operations such
as ladle repair, skull burning, and teeming that occurred randomly
during the test program.  However, the contribution of these ancillary
operation emissions to observed roof monitor opacity was minimal.  The
reason that visible emissions from nonaffected facilities were included
is that it is difficult during normal shop operations to isolate the
affected facilities from nonaffected facilities.  However, the intention
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 is  not  to  regulate  existing facilities  by_this  means.   This  is  evident
 from  the provisions of §60.145a of the  final  rules,  which  permit shop
 operations  not  subject to  Subpart  Na  to be  suspended during  compliance
 testing (for  both mass and visible emissions).
      As noted in the proposed  rulemaking (p.  2668),  Method 9 readings
 were  taken  for  top-blown furnaces  during the  operation  of  these unaffected
 facilities.   Because the visible emission standard is based  on  these
 data, compliance can be demonstrated  while  these operations  continue.
 This  permits  compliance testing without the disruption  of  normal  shop
 operations.   However,  the  regulation  does permit the shutdown of
 unaffected  operations  so that  compliance can  be based only on emissions
 from  affected operations.
 2.6   EMISSION TESTING  AND  MONITORING
 2.6.1   Comment:   (IV-D-4)   One  commenter stated that the reduced
 testing time  for top-blown  BOPF  primary emissions is a  strong disin-
 centive for owners  to  modernize  existing top-blown BOPF equipment
 because, then, the  existing gas-cleaning device may  also have to be
 improved.   The commenter also  noted that effects of  primary  gas-cleaning
 system  operating parameter modification  on  secondary emissions were
 not addressed.  The commenter  recommended that the primary emission
 standard for  top-blown  BOPF's  specified  in  §60.144(b)(2) be  limited to
 newly constructed furnaces and that the  effects of primary gas-cleaning
 system  changes on secondary emissions be addressed.
     Response:  The intent is not to discourage the modernization of
 existing BOPF equipment.  Modernization  taking the form of modifications
 not increasing total particulate emissions and not exceeding the
 reconstruction fixed capital cost limitation of 40 CFR 60.15 may be
made without subjecting the facility to the requirements of §60.144(b)(2);
40 CFR 60.14(e)  also lists  some physical or operational  changes  that
are not considered modifications, irrespective of any changes in the
emission rates.   Beyond this, however, the intent of Section 111 is to
require new, modified, or reconstructed facilities to apply BDT.
     The commenter1s assertion that changes  in the primary control
system operating parameters may affect secondary emissions  is correct.
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Fugitive emissions from furnace operations, not captured by the primary
hood, may increase or decrease depending on the changes in primary
control device operating parameters.  However, the modification or
reconstruction that makes the facility subject to §60.144(b)(2) also
causes the facility to be subject to Subpart Na for control of secon-
dary emissions.  Compliance with both provisions of the regulation may
be achieved in a number of ways, some of which do not require changes
in the primary system operating parameters that would adversely affect
secondary furnace emissions.  It is up to the owner or operator of the
facility to select the most economical means of achieving compliance
for the particular situation.
2.6.2  Comment:  (IV-D-2)  One commenter cited §60.144(b)(l) of the
primary standard, which states, "A cycle shall start at the beginning
of either the scrap preheat or the oxygen blow and shall terminate
immediately prior to tapping."  The commenter believes a contradiction
exists between this section and a statement under "Review of the
Primary Standard" that says reblows would not be considered part of
the primary oxygen blow under the proposed revision.   He also indicated
that the minimum sample volume of 32 dscf for §§60.144(b)(l) and (2)
proposed for the primary standard (Subpart N) is too small and recom-
mended a minimum volume of 60 dscf.
     Response:  The paragraph on page 2669 of the Federal Register
proposal notice referring to reblows not being considered part of the
primary oxygen blow refers to the proposed revisions to existing
Subpart N for primary emissions from BOPF's.  It is the intent that
the revisions discussed under "Review of the Primary Standard," which
require mass testing only during the primary blow, apply only to
facilities that commence construction, modifications, or reconstruction
after January 20, 1983, as stated in §60.144(b)(2).   Affected facilities
commencing construction, modifications, or reconstruction on or before
January 20, 1983, must sample in accordance with the provisions as
described in §60.144(b)(l), which require testing during the steel
production cycle, including reblows.  Therefore, no contradiction
exists.
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     As  a  result  of a  review of  the proposed minimum  sample  volume
 specified  in §60.144(b)(l) and 60.144(b)(2) of the primary standard,
 the  required minimum sample volume has been increased from 0.9 dscm
 (32  dscf)  to 1.5  dscm  (53 dscf).  The minimum sample  volume  was revised
 to provide an allowance for a 50-mg particulate catch on the sampling
 train filter, taking into account collection of particulate  matter in
:the  nozzle and on the  walls of the sampling probe.  This increase in
 minimum  sample volume  is needed  to maintain test precision.  The
 minimum  sample volume  was not increased to 60 dscf because 1.5 dscm
 (53  dscf)  was judged to be sufficient to provide the  50-mg particulate
 catch without unnecessarily increasing the test length and the cost of
 performance testing.   These revised sample volume requirements are
 applicable to facilities constructed, modified, or reconstructed after
 January  20, 1983, and  to existing affected facilities subject to
 Subpart  N  (i.e.,  those BOPF's constructed, modified,  or reconstructed
 after June 11, 1973, but on or before January 20, 1983).  As proposed,
 shorter  sampling  times and smaller sample volumes would be allowed,
 subject  to approval by the Administrator, when necessitated  by process
 variables  or other factors,
 2.6.3  Comment:    (IV-D-2)  One commenter suggested that performance
 tests for  secondary mass emission limitations should be performed only
during portions of the production cycle that include a specific secon-
dary emission activity;, e.g.,  hot metal  charging.   The commenter
 stated that inclusion of other low-emitting portions of the production
cycle,  such as scrap charge,  dilutes  the sample.   To accommodate his
suggested change, the commenter recommended the use of a high-volume
Method 5 sampler to compensate for the difficulty of obtaining sufficient
sample from operations of such short  durations.   If high-volume Method 5
samplers are not required,  the commenter recommended that the minimum
sampling volume be increased  from 80  dscf to 160 dscf to minimize
sample recovery errors and  to  maintain reasonable precision from test
to test.
     Response:   The possibility of sampling the secondary emission
controls system only during the occurrence of high-emission operations,
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such as hot metal charging, tapping, and hot metal transfer, was con-
sidered during the development of the proposed standard.  However,
most of the test data available on particulate concentrations at the
outlet from fabric filters serving secondary emission sources were not
obtained in this manner, but rather by sampling over both high- and
low-emitting portions of the cycle.
     Because the secondary emission operations of hot metal transfer
and skimming may occur independently of furnace operations and be
ducted to the same secondary control device, limiting emission testing
to just the typically high-emitting secondary operations unnecessarily
complicates the performance tests.  For both of these reasons, sampling
was proposed over the entire steel production cycle.   Because it is
believed that sampling over the entire steel production cycle is
appropriate, no further consideration was given to the use of high-
volume Method 5 sampling trains.   However, the minimum required sampling
volume for each sample run has been increased from 2.27 dscm (80 dscf)
to 5.67 dscm (200 dscf).  This change has been made to ensure that
adequate particulate matter is sampled to maintain test precision.-  A
new provision was also added to the final rules, which allows shorter
sampling times and lower sample volumes when necessitated by process
variables or other factors, subject to approval by the Administrator.
     In regard to Method 5, it should be recognized that a new Method
5d was proposed recently for use with positive-pressure baghouses
(48 FR 37354, August 17, 1983).  Although the final standards cannot
require the use of Method 5d until the Method is promulgated, owners
and operators of positive-pressure baghouses may choose to take advantage
of §60.13(i) of the NSPS General  Provisions, which allows the use of
alternative test methods.
2.6.4  Comment:   (IV-D-2)  One commenter stated that if it is agreed
that emissions from the secondary control device should be sampled
only during high-emitting portions of the production cycle, EPA Refer-
ence Method 2 should be revised.   The basis for this comment is that
velocity readings provided by noncontinuous sampling would not yield
accurate flow rate data.  The commenter believes that accurate flow
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 rate  data, while  not  essential  to  the  proposed  concentration  standard,
 will  be  necessary to  calculate  emission  rates for State  or  local
 agency standards.  The commenter also  recommended a continuous  flow
 rate  monitoring device to assist in determination of mass emission
 rates.
      Response:  For the reasons stated in the response to the previous
 comment, disagreement exists concerning  the commenter1s  view that
 secondary emission sampling should be  conducted only during high-emitting
 portions of the steel production cycle.  It is believed  that velocity
 readings obtained continuously during  Method 5 sampling  will provide
 an adequate basis for estimating the mass emission rate  from the
 secondary control device over the entire production cycle.  The proposed
 regulation would  not  preclude State or local agencies from adopting
 their own requirements for flow rate measurements needed to determine
 compliance with their emission standards.
      The monitoring provisions of §60.143a require the owner or operator
 to install a monitoring device or devices to continually monitor and
 record the various rates or levels of  exhaust ventilation through each
 duct,of the secondary emission control system for each phase of each
 steel production  cycle.   The monitoring and recording of ventilation
 rates or levels will  ensure proper operation and maintenance of the
 secondary emission capture system.   Other revisions made to the monitor-
 ing requirements  since proposal are discussed in the response to
 comment 2.7.3.  The commenter's suggestion that the continuous flow
 rate monitor can be used to determine  volumetric flow rate during a
 stack test and subsequent calculation of mass emission rate may be
 useful to State or local  agencies with mass emission rates rather than
concentration standards.
2.6.5  Comment:  (IV-D-2)  One commenter agreed that process monitoring
should be required during all  compliance testing but believed a list
of process variables and control device variables that could affect
the results of a test should be included for use during testing.
     Response:  We agree that such  a list would be helpful  to monitor
the process and control  device operations properly during performance
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testing.  However, the variety of emission control system designs and
the variation of process  equipment and operations in plants make the
development of a universally applicable and comprehensive list a
difficult task.  Furthermore, the use of a universally applicable list
suggests that information may be requested from a plant that will not
be useful in its specific case, therefore increasing the associated
testing burden for the owner or operator of this facility.  For these
reasons, it was decided not to publish a list of recommended or required
process and control device variables to be monitored.
2.6.6  Comment:  (IV-D-2) One commenter suggested that the steel
production cycle should not be used to characterize BOPF secondary
visible emissions from hot metal charging, tapping, hot metal transfer,
and skimming.  The commenter suggested using those individual operations
as the basis for characterization.  He stated that this would provide
more realistic data on the effectiveness of controls for these specific
operations, rather than the visible emission effects of unregulated
.ancillary operations.
     Response:  In the initial analyses of roof monitor visible emission
test data, the characterization of the data on the individual operation
basis was considered, as  suggested by the commenters.  Other approaches
to characterizing the data were considered as well.   Use of the steel
production cycle as the basis for characterization was selected for
two reasons.  One reason  was that the secondary emission control
systems may be used to control emissions from several secondary sources,
especially in newer plants when closed hood primary control systems
are selected.  With such  a secondary system, several secondary process
operations may occur simultaneously, sometimes related to two furnace
vessels, hampering the effort to obtain visible emission data for
separate secondary emission processes.  The second reason was that
roof monitor visible emissions lag behind the actual process operation
that generates them.  Determining when to cease observations because
all emissions from the particular secondary operations have left the
roof monitor is difficult.  The fact that five potential secondary
emission sources exist, including puffing emissions escaping the
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 primary hood,  compounds this problem.   Using the steel  production
 cycle to characterize these secondary emissions  minimizes  or eliminates
 the above difficulties.
      The commenter's  point about the effect of unregulated ancillary
 operations on  observed secondary visible  emissons from  regulated
 sources is addressed  in the response to comment  2.5.4.
 2.7  EQUIPMENT,  DESIGN,  AND OPERATING SPECIFICATIONS
 2.7.1  Comment:   (IV-D-2)   One  commenter  agreed  with  the preamble
 (p.  2661) that the  use of  operating  practices  conducive to lesser fume
 generation is  very  important in reducing  secondary emissions.   These
 practices include the use  of clean scrap,  slow pouring  techniques,
 careful  positioning of the hot  metal  ladle,  and  proper  furnace  tilt
 angle.   However,  this commenter questioned why these  practices  are not
 required by the  proposed standards to  ensure successful secondary
 emissions control.
      Response:   Section  lll(h)(l) of the  Clean Air Act  provides  that,
 "If in  the judgment of the Administrator,  it is  not feasible to  prescribe
 or  enforce a standard of performance.,  he  may instead  promulgate  a
 design,  equipment,  work  practice, or operational  standard, or combina-
 tion  thereof,  which reflects  the best  technological system of continuous
 emission  reduction  that  (considering the  cost  of  achieving such  emission
 reduction and  any nonair quality health and  environmental  impact  and
 energy  requirements)  the Administrator determines  has been adequately
 demonstrated . .   .  ."
      The  phrase "not  feasible to prescribe or  enforce" means "any
 situation  in which  the Administrator determines that  (A) a pollutant
 or pollutants  cannot  be  emitted through a conveyance  designed and
 constructed to emit or capture  such pollutant, or that any requirement
 for,  or use of, such  a conveyance would be inconsistent with any
 Federal,  State, or  local law, or (B) the application of measurement
 methodology to a particular class of sources is not practicable due to
 technological   or economic  limitations" [lll(h)(l)-(2)].
     As explained at 48  FR 2658, the proposed standards of performance
were based on BDT for BOPF's and hot metal transfer and skimming
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stations.  For secondary emissions from a top-blown furnace, the open
hood primary emission control system that also controls secondary
emissions was selected as BDT.  For hot metal transfer and skimming
stations, local hooding ducted to a baghouse was selected as BDT.
     For each affected facility, particulate matter can be captured
via the primary or secondary hood.  Measurement methodology (Reference
Method 5) is available to ascertain the concentration of particulate
matter at the outlet of the collection device.  Because it is feasible
to prescribe and enforce a standard of performance for this source
category, an emission limit format was selected for BOPF collection
devices in lieu of specifying work practice or equipment, design, and
operational requirements.  Opacity limits are also included as a
supplement to the concentration limits because visible emissions act
as a good indicator of the secondary emission control system performance
and as an indicator of proper operation and maintenance of the device.
     While it is true that the application of these practices is
conducive to lesser fume generation, the total impact of these practices
on resulting emission reductions for all types of BOPF's is not clear.
Many of the work practices were observed at the J&L/Aliquippa and
Bethlehem/Bethlehem shops, both of which use a primary hood to control
secondary emissions from top-blown furnaces.  Application of these
practices appeared beneficial in secondary emission control for these
systems.   However, it is not clear that these practices resulted in a
significant impact on secondary emission control at the top-blown/closed
hood system at Kaiser/Fontana.
     Because the impact of these practices on the secondary control
system for each type of furnace or control system cannot be fully
quantified in terms of the resulting emission reductions, the standard
does not require their application to supplement the secondary emission
control afforded by the application of BDT.  Consequently, the imple-
mentation of these practices may not be necessary to achieve the
emission limits, whether concentration or opacity.  This should not
imply that any good operating practices consistent with minimizing
emissions should not be applied to the extent practicable, as required
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under §60.11(d).  For example, these practices may have a significant
impact for open hood primary systems used to control secondary emissions;
and although the degree of impact on other types of systems is unclear,
the application of these practices is encouraged for each BOPF facility,
whether or not subject to the standards of performance.
2.7.2  Comment:  (IV-D-2)  One commenter agreed with the preamble
(p. 2661) that a separate capture and collection system is necessary
for a closed hood primary system controlling secondary emissions from
the furnace in order for the closed hood system to achieve a control
efficiency similar to that of the open hood system.  The proposed
capture system for closed hood systems consists of a furnace enclosure
evacuated by auxiliary hooding ducted to a high-efficiency collection
device, such as a baghouse.  The commenter recommended that minimum
guidelines for hood size and extensions and for fan evacuation capacity
be established, based on data from existing systems that meet the
proposed standards.
     Response:   As explained in the response to comment 2.7.1, a
numerical emission limit was selected as the format of the standard in
lieu of work practices or equipment,  design, and operating specifications.
This approach offers certain advantages compared to equipment and
design specifications (e.g., hood size and fan evacuation capacity)
because any equipment capable of meeting the emission limits can be
used to achieve compliance.  In addition, the operating parameters of
the equipment can be tailored to meet the needs of the particular
facility.   Designs and operating specifications for secondary emission
control systems are expected to vary according to the type of vessel
and the differences in operating parameters and procedures among
existing shops.  For example, shop structure could influence the size
or location of auxiliary hooding.   Also, fan evacuation capacity
specifications  may vary,  depending on the amount of dilution air
entrained into  the system.   Because of the differences in design and
operating parameters among BOPF shops,  the establishment of equipment
and design specifications based on data from existing shops could
limit the flexibility needed by BOPF  owners and operators,  particularly
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in retrofit situations.  For these reasons, equipment, design, or
operational requirements are not included in the promulgated standards.
2.7.3  Comment:   (IV-D-2)  This commenter agreed that the exhaust
ventilation rate  is an important monitoring parameter to determine if
the secondary capture system is operating effectively.  However, he
suggested that a  baghouse pressure drop monitoring device also be
considered.  The  addition of this device would ensure that the baghouse
is being properly cleaned and is working at the design air-to-cloth
ratio for the effective removal of captured emissions.
     Response:  As explained at 48 FR 2667, Clean Air Act requirements
relating to the operation and maintenance of a source are generally
included in new source standards of performance in the form of monitor-
ing requirements.  The operating parameters selected for monitoring
requirements should be related to the performance of the emission
control system and should be parameters that can be monitored without
an unreasonable burden on the owner or operator.
     Both exhaust ventilation rate and baghouse pressure drop are
considered good indicators of the effectiveness of the secondary
emission control  system.   However, a drop in exhaust ventilation rate
is the better indicator of the control system performance, while
baghouse pressure drop is the better indicator of the performance of
the collection device.  Exhaust ventilation rate or level  was selected
as the monitoring parameter because it provides a better indicator of
overall secondary emission control system performance.
     In regard to the secondary emission collection device,  however,
the opacity limit of 5 percent serves to supplement the monitoring
requirement for exhaust ventilation rate or level.   The opacity limit
is also a good indicator of the effectiveness of the secondary emission
collection device because degredation in baghouse performance will
result in increased opacity.   The monitoring of exhaust ventilation
rate or level, coupled with the opacity limit,  would provide a good
indication of both the control  system performance and the  effective-
ness of the collection device.   Consequently,  it appears unnecessary
to require the continual  monitoring and recording of both  exhaust
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 ventilation rate and baghouse pressure drop.   Also,  most new baghouse
 systems are equipped with pressure drop indicators.   Although these
 indicators do not provide a continual  record,  they are considered
 sufficient to signal potential  operating or maintenance needs for a
 baghouse before increased opacity results.
      Review of the requirement for monitoring  of exhaust ventilation
 rate as the secondary emissions monitoring  parameter resulted in an
 examination of new monitoring systems  for application to BOPF's.   New,
 inexpensive systems are now available  that  allow the owner or operator
 to  measure and record changes in the level  of  exhaust ventilation
 through the system.   The cost of the entire monitoring and recording
 system is estimated at less than $2,000,  with  backpurge,  for each
 installation.   For this reason,  the final regulation was  modified to
 require the monitoring and recording of the various  exhaust rates or
 the monitoring and recording of the exhaust levels through each  duct
 of  the system.
      The compliance provisions  were also  expanded  in the  final rules
 to  require that during compliance testing of a single furnace  at  a
 shop that normally operates two  furnaces  with  overlapping  cycles,  the
 owner or operator  must maintain  an  exhaust  ventilation  rate  or level
 in  each duct of the secondary emission  control system that is  appropriate
 for single-furnace operation.  After the  compliance  test,  the  owner  or
 operator must  maintain for  each  duct exhaust ventilation rates or
 levels  that  are  no lower than 90  percent  of the values  established
 during  the most  recent compliance test.  Monitoring  records  indicating
 lower rates  (or  levels) through  the ducts may  indicate  improper operation
 or  maintenance  of  the  system.  The owner or operator must  also report,
 on  a  semiannual  basis,  all  measurements over any 3-hour period that
 average  more than  10 percent below the average levels maintained
 during  the most  recent  compliance test for determining compliance with
 the mass  standard  for secondary emission collection devices.  A similar
 provision requiring semiannual reporting also was added to the final
 standards for monitoring results of scrubber pressure drop.  This
 requirement would apply if a scrubber primary emission control device
were  used to collect secondary emissions.
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     Other revisions to the monitoring requirements since proposal
include the use of the term "continual" monitoring rather than "con-
tinuous" monitoring to avoid confusion with the type of continuous
monitoring system defined under §60.2 of NSPS General Provisions.
Also, a new provision was added to the final standards that requires
the owner or operator to place the monitoring device (or devices) at
capture points for the secondary emission control system; alternative
locations for the monitoring device(s) must be approved in advance by
the Administrator.  The final standards also include a provision for
the use of -a strip chart recorder, the most common form of recordkeeping.
This provision would require that if a strip chart recorder is used,
it must be operated at a minimum chart speed of 3.8 cm/hr (1.5 in./hr).
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                              TECHNICAL REPORT DATA
                        (Please read Instructions on the reverse before completing)
 1. REPORT NO.
  EPA-450/3'-.R3-nngh
                                                   3. RECIPIENT'S ACCESSION NO.
 4. TITLE AND SUBTITLE
  Revised Standards for Basic Oxygen Process
  Furnaces—Background Information for
  Promulgated Standards
           5. REPORT DATE
                 December  1985
           6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
                                                   8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING'ORGANIZATION NAME AND ADDRESS
  Environmental Protection Agency
  Office  of  Air Quality Planning and Standards
  Emission Standards and Engineering Division
 , Research Triangle Park, North Carolina 27711
                                                   10. PROGRAM ELEMENT NO.
           11. CONTRACT/GRANT NO.
             68-02-3056
 12. SPONSORING AGENCY NAME AND ADDRESS
 :DAA for Air Quality Planning  and Standards
  Office of  Air,  Noise, and Radiation
  United States Environmental Protection Agency
 'Research Triangle Park, NC  27711
           13. TYPE OF REPORT AND PERIOD COVERED
             Final
           14. SPONSORING AGENCY CODE


             EPA/200/04
 15. SUPPLEMENTARY NOTES
      _A New Source Performance Standard for secondary emissions of
  participate matter from basic oxygen process furnace (BOPF)  steelmaking
  shops is oeing  promulgated under  authority of Section 111 of the Clean
  Air Act.  This  final action is applicable to.secondary emissions from
 •;any top-blown BOPF arid to any hot metal transfer station or skimming '
 :station used for a bottom-blown or  top-blown BOPF,  for which constructicn,
  reconstruction,  or modification commenced after January 20,  1983.  The
  purpose of the  final standard is  to minimize BOPF secondary particulate
 .emissions to the level attainable with the best demonstrated technolocry
 .Amendments to the existing BOPF primary standard (40  CFR 60  140
  Subpart N) are  also being promulgated.   These amendments to Subpart N
 .apply to primary emissions from BOPF's constructed,  reconstructed, or
 •                                                              reconstruct^.
                           KEY WORDS AND DOCUMENT ANALYSIS
               DESCRIPTORS
                                       b. IDENTIFIERS/OPEN ENDED TERMS
                                                              c.  COSATI Field/Group
 Air Pollution
 Pollution Control
 Standards of Performance
 Basic Oxygen Process Furnaces
 Opacity
 Particulates
Air Pollution Control
                           13 B
 Unlimited
                                       19. SECURITY CLASS (This Report)
                                        Unclassified
                      21. NO. OF PAGES
                           65
                                       20. SECURITY CLASS (Thispage)
                                        Unclassified
                      22. PRICE
EPA Form 2220-1 (Rev. 4-77)   PREVIOUS EDITION IS-OBSOLETE

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