Document ID: EPA-HQ-OAR-2002-0086-0018
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-07-22T04:00Z

MEMORANDUM

		

SUBJECT:	National Emission Standards for Hazardous Air Pollutants for
Semiconductor Manufacturing Final Rule, Response to Comments

FROM:	John Schaefer

Environmental Engineer

OAQPS/SPPD/MPG

TO:		Docket

DATE:	June 06, 2008

Background

The final rule for semiconductor manufacturing was published in the
Federal Register on May 22, 2003, at 68 FR 27913.  After promulgation of
the NESHAP, it was brought to our attention that while the NESHAP
established separate emission standards for organic and inorganic HAP
from process vents, one plant had a different process vent system. 
Specifically this plant combined inorganic and organic vent streams into
a single atmospheric process vent.  At the time we developed the MACT
standard, we were not aware of any sources that combined their inorganic
and organic vent streams.  

Rather during the development phase of the rule, we determined that
since 1980 industry practice had been to strictly separate process vent
emissions into streams containing either organic or inorganic HAPs. In
order to address the combined process vent streams, on October 19, 2006,
we proposed amending the final rule by establishing emission standards
for existing and new combined process vent streams.  For the limited
number of existing combined process vents, we proposed no control. For
new and reconstructed combined HAP process vents, we proposed the same
requirements that currently apply to new inorganic HAP process vents and
new organic HAP process vents.

Subsequently, the D.C. Circuit in Sierra Club v. EPA, Case No. 03-1202
(D.C. Cir., March 13, 2007), found that EPA’s decision to set no
control emission floors for source categories where the best performing
sources did not use emission control technology was in direct
contravention of Clean Air Act section 112(d)(3).  Therefore, a
supplemental proposal package was developed to bring the proposed rule
amendments into compliance with the D.C. Circuit Court’s decision. 
The supplemental proposal packaged was published in the Federal Register
at These amendments were proposed on April 2, 2008 and added an emission
limitation of 14.22 ppmv HAP for new and existing combined HAP process
vents to bring the final rule into compliance with the D.C. Circuit
Court Decision.

We received one comment on the October 19, 2006 proposal and two
comments on the April 2, 2008 proposal.  All three comments were
supportive of the proposed changes. 

  SEQ CHAPTER \h \r 1 TABLE 1.  List of Commenters on the Proposed
Amendments to the National Emission Standards For hazardous Air
Pollutants: Semiconductor Manufacturing

Comment

Number	

Docket Item Number	

Commenter and Affiliation	Date of Letter

1	  HYPERLINK
"http://www.regulations.gov/fdmspublic/custom/jsp/search/searchresult/do
cketDetail.jsp" \l "#" \o "EPA-HQ-OAR-2002-0086-0009" 
EPA-HQ-OAR-2002-0086-0009 	Gregory A. Smith, Eastman Kodak Company
12/05/2006

2	Not Assigned

	Roy W. Wood, Eastman Kodak Company	04/29/2006

3	  HYPERLINK
"http://www.regulations.gov/fdmspublic/custom/jsp/search/searchresult/do
cketDetail.jsp" \l "#" \o "EPA-HQ-OAR-2002-0086-0009" 
EPA-HQ-OAR-2002-0086-00 16 	Anonymous Commenter, Unaffiliated with an
organization	05/02/2006

Response to Comments

	We received 2 comments from Kodak Semiconductor that were supportive of
the proposed changes.  Both comments were supportive of the propose
changes and supported EPA position that combined HAP process vents are
technically different from segregated organic and inorganic HAP process
vent streams at modern semiconductor manufacturing fabs.  A third
comment from an anonymous commenter was also supportive of the proposed
changes.  A summary of the comments is presented below, due to the
similarity of all of the comments received, it is only necessary to
summarize the main points from Kodak comment letter submitted on
04/29/2006.

A.  Development of a Separate MACT Floor

	Comment:  One commenter (Commenter 3) expressed support for the
development of a separate MACT floor level of control for combined HAP
process vents contained in the April 2, 2008 proposal.  The commenter
stated, “This action appropriately recognizes that a limited number of
process vents at older, existing facilities have unique emission
characteristics that warrant distinction from the process vents used to
establish the original MACT floor.”  The commenter gave a description
of the typical construction of a modern semiconductor facility
indicating that clean rooms are situated on a single floor with
semiconductor manufacturing tools arranged in cells of similar tools
(e.g. web benches, furnaces, etc. are grouped together).  The commenter
stated that these features and other features in a modern semiconductor
facility make the segregation and treatment of concentrated organic and
inorganic HAP emission streams feasible.  However, segregating emission
streams into their organic and inorganic constituents was near
infeasible for some older facilities, such as the one described by the
commenter, where tools are located on three separate floors, and are not
grouped together in cells according to tool function and type.  Due to
these reasons the commenter indicated strong support for EPA’s
development of a separate MACT floor for combined HAP process vents. 

	Response:  We agree with the commenter that the proposed changes to the
standard are necessary to account for the limited number of older
facilities that do not segregate their emissions due to facility design
limitations.  Today’s rule reflects our conclusion that a separate
MACT floor for these facilities is appropriate.  Therefore, as stated
earlier we are promulgating definitions that clarify the applicability
of the existing NESHAP and an emissions limitation of 14.22 ppmv for new
and existing combined HAP process vents.

B.  Technical Factors affecting control cost and efficacy for Combined
HAP process vents

Comment:   One commenter (Commenter 3) expressed support for EPA’s
determination that combined HAP process vent streams that contain
inorganic and organic HAP and added process heat are more costly and
difficult to control than segregated process vent streams.  The
commenter stated, “The commingling of process ventilation containing
heat, organic HAP, and inorganic HAP present a unique set of conditions
that negatively affect control efficacy and cost efficiency.”   The
commenter said they concur with the EPA that a combined HAP process vent
stream needs a much larger and more expensive scrubber than a similar
inorganic process vent at a more modern facility.  The commenter also
said they agree EPA’s observation that added process heat affects wet
scrubber efficiency that must be mitigated through scale or thermal
conditioning.  The commenter stated that these, “technical factors
provide a compellingly basis for the new MACT floor determination.”

Response:  We agree with the commenter that the technical differences
between combined HAP process vents at older semiconductor facilities and
segregated HAP process vent streams found at more modern facilities
provide a sound technical basis for the development of a separate floor
for combined HAP process vents.  In our original proposal on October 19,
2006 we stated that we would have developed a separate floor for
combined HAP process vents had we been aware of their existence at the
time.   Therefore, we are promulgating the combined HAP process vent
control requirements as proposed in the October 19, 2006 and April 2,
2008 amendments.APPENDIX A: COMMENT LETTERS

Commenter: Gregory A. Smith, Eastman Kodak Company

Date: 12/04/06

Docket Number:	  HYPERLINK
"http://www.regulations.gov/fdmspublic/custom/jsp/search/searchresult/do
cketDetail.jsp" \l "#" \o "EPA-HQ-OAR-2002-0086-0009" 
EPA-HQ-OAR-2002-0086-0009 

Re:	Eastman Kodak Company Comments on National Emission Standards for
Hazardous Air Pollutants for Semiconductor Manufacturing; Proposed Rule
(October 19, 2006), Docket ID No. EPA-HQ-OAR-2002-0086

Dear Sir:

Eastman Kodak Company manufactures imaging sensors at a relatively small
semiconductor fabrication facility (fab) in Rochester, New York.  We
have reviewed the amendment to the NESHAP for Semiconductor
Manufacturing (40 CFR Part 63 Subpart BBBBB) proposed by EPA on October
19th of this year, and are pleased to submit the following comments. 

	Kodak strongly supports EPA’s development of a MACT floor level of
control for combined HAP process vents.  This action appropriately
recognizes that a limited number of process vents at older, existing
facilities have unique emission characteristics that warrant distinction
from the process vents used to establish the original MACT floor.       

Modern fabs are typically (and unsurprisingly) built for their intended
manufacturing purpose using a common set of basic design principles.
Cleanrooms are typically situated on a single floor of a fab, with air
handling and support equipment located on the floors above and below the
cleanrooms, respectively.  Similarly, semiconductor manufacturing tools
such as furnaces, wet benches, etc. are typically arranged in cells of
like tools.  These and other design features facilitate the segregation
and treatment of concentrated organic and inorganic HAP emissions in a
manner consistent with EPA’s original MACT floor analysis.  EPA states
in the preamble to the proposed amendments that these design principles
have been common practice in the industry since the early 1980s, but
notes that at least one older facility in current operation reflects an
earlier design philosophy in which organic and inorganic HAP are
routinely combined in process vents that are also used for the removal
of excess process heat.  

Kodak’s fab, which is located in a five-story building addition
constructed more than twenty-five years ago for microelectronics
research, exhibits the earlier design philosophy described by EPA. 
Process vent emission characteristics in this facility are primarily a
legacy function of the original facility design, since the existing
layout and infrastructure limit the practical options available for
equipment placement and ventilation service. Cleanroom space, for
example, is situated on three different floors of the addition, and
tools with similar emission characteristics are scattered throughout the
fab.  As a result, organic and inorganic process HAP emissions are
captured by multiple exhaust drops proximate to the various unit
operations, and combined in the main ductwork of the multistory
ventilation systems.  These exhaust drops are also frequently used to
collect and dissipate process heat.    

We believe that EPA properly concluded in the proposed amendment that
combined HAP emissions from older existing semiconductor manufacturing
plants - such as the facility operated by Kodak - belong in a distinct
category of process vent emissions subject to a unique MACT floor
determination.  The commingling of process ventilation containing heat,
organic HAP, and inorganic HAP present a unique set of conditions that
negatively affect control efficacy and cost efficiency.  Commingling is
inherently dilutive, and EPA correctly notes the impairment of wet
scrubber organic HAP removal efficiency at low pollutant concentration. 
We concur with the Agency’s conclusion that “a combined HAP vent
stream needs a much larger and more expensive scrubber to control a
combined HAP process vent than a similar inorganic process vent at a
more modern facility.” We also support the Agency’s observation that
added process heat affects wet scrubber partitioning efficiency and must
be mitigated through scale or thermal conditioning.  These factors
provide a compelling basis for the new MACT floor determination.

We note in consideration of scope of impact that EPA’s approach to
this necessary revision is appropriately limited, since the amended rule
would not change the organic and inorganic HAP emission limits
applicable to combined HAP process vents at new and reconstructed
sources, wherein segregation and abatement of concentrated HAP emissions
can be feasibly managed by utilizing modern design principles.    

In summary, Kodak believes that the proposed amendments to Subpart BBBBB
are justified and well reasoned, and should be carried forward to
promulgation.  

  

 Sincerely, 

Gregory A. Smith

Environmental Engineer

Eastman Kodak Company

1669 Lake Avenue

Rochester, NY  14652-4543

(585) 722-3126

  HYPERLINK "mailto:gregory.a.smith@kodak.com" 
gregory.a.smith@kodak.com 

Commenter:  Roy W. Wood, Eastman Kodak Company

Date:  05/20/2008

Docket Number:	  HYPERLINK
"http://www.regulations.gov/fdmspublic/custom/jsp/search/searchresult/do
cketDetail.jsp" \l "#" \o "EPA-HQ-OAR-2002-0086-0009"  Submitted 
Directly to John Schaefer, not received by the Docket during the comment
period.

Re:	Eastman Kodak Company Comments on National Emission Standards for
Hazardous Air Pollutants for Semiconductor Manufacturing; Proposed Rule
(April 2, 2008), Docket ID No. EPA-HQ-OAR-2002-0086

Dear Sir:

Eastman Kodak Company manufactures imaging sensors at a relatively small
semiconductor fabrication facility (fab) in Rochester, New York.  We
have reviewed the amendment to the NESHAP for Semiconductor
Manufacturing (40 CFR Part 63 Subpart BBBBB) proposed by EPA on April 2
of this year, and are pleased to submit the following comments. 

Kodak strongly supports EPA’s development of a separate MACT floor for
combined HAP process vents.  The proposed standards in this April 2,
2008 proposal will properly control emissions from these three different
types of sources when promulgated in combination with the previously
proposed 63.7195 definitions for inorganic HAP Process Vent, Organic HAP
Process Vent and Combined HAP Process Vent (71FR61701, October 19,
2006).  This action appropriately recognizes that a limited number of
process vents at older, existing facilities have unique emission
characteristics that warrant distinction from the process vents used to
establish the original MACT floor.        

Modern fabs are typically (and unsurprisingly) built for their intended
manufacturing purpose using a common set of basic design principles.
Cleanrooms are typically situated on a single floor of a fab, with air
handling and support equipment located on the floors above and below the
cleanrooms, respectively.  Similarly, semiconductor manufacturing tools
such as furnaces, wet benches, etc. are typically arranged in cells of
like tools.  These and other design features facilitate the segregation
and treatment of concentrated organic and inorganic HAP emissions in a
manner consistent with EPA’s original MACT floor analysis.  EPA states
in the preamble to the proposed amendments that these design principles
have been common practice in the industry since the early 1980s, but
notes that at least one older facility in current operation reflects an
earlier design philosophy in which organic and inorganic HAP are
routinely combined in process vents that are also used for the removal
of excess process heat.  

Kodak’s older fab has issues that are similar to those described by
EPA for older facilities.  It is located in a five-story building
addition constructed more than twenty-five years ago for
microelectronics research.  The existing layout and infrastructure limit
the practical options available for equipment placement and ventilation
service. Cleanroom space is situated on three different floors of the
addition, and tools with similar emission characteristics are scattered
throughout the fab.  As a result, organic and inorganic process HAP
emissions are captured by multiple exhaust drops proximate to the
various unit operations, and combined in the main ductwork of the
multistory ventilation systems.  These exhaust drops are also frequently
used to collect and dissipate process heat.    

We believe that EPA properly concluded in the proposed amendment that
combined HAP emissions from older existing semiconductor manufacturing
plants - such as the facility operated by Kodak - belong in a distinct
category of process vent emissions subject to a unique MACT floor
determination.  The commingling of process ventilation containing heat,
organic HAP, and inorganic HAP present a unique set of conditions that
negatively affect control efficacy and cost efficiency.  Commingling is
inherently dilutive, and EPA correctly notes the impairment of wet
scrubber organic HAP removal efficiency at low pollutant concentration. 
We concur with the Agency’s conclusion that “a combined HAP vent
stream needs a much larger and more expensive scrubber to control a
combined HAP process vent than a similar inorganic process vent at a
more modern facility.”  We also support the Agency’s observation
that added process heat affects wet scrubber partitioning efficiency
that must be mitigated through scale or thermal conditioning.  These
factors provide a compellingly basis for the new MACT floor
determination.

In addition , older fabs are typically smaller than more modern fabs, so
the emissions are correspondingly smaller.  Because of its small size,
Kodak’s fab is located within a building that is otherwise devoted to
research activities.  Most research activities are not even covered by
MACT regulations because of their small size and relatively
insignificant emissions.  Kodak’s semiconductor manufacturing
emissions are less than one ton per year.

EPA’s approach to this necessary revision is appropriately limited,
since the amended rule would not change the organic and inorganic HAP
emission limits applicable to combined HAP process vents at new and
reconstructed sources where segregation and abatement of concentrated
HAP emissions can be feasibly managed by utilizing modern design
principles.    

In summary, Kodak believes that the proposed amendments to Subpart BBBBB
are justified and well reasoned, and should be carried forward to
promulgation.  

Please contact me if you have any questions about these comments.

  

Sincerely, 

Roy W. Wood

Health Safety and Environment

Eastman Kodak Company

1669 Lake Avenue

Rochester, NY  14652-4543

(585) 588-7538

Roy.wood@kodak.com

Commenter: Anonymous Commenter, Unaffiliated with an organization

Date: 05/02/2008

Docket Number:	  HYPERLINK
"http://www.regulations.gov/fdmspublic/custom/jsp/search/searchresult/do
cketDetail.jsp" \l "#" \o "EPA-HQ-OAR-2002-0086-0009" 
EPA-HQ-OAR-2002-0086-0016 

I think that adding this amendment is a great idea. It is important to
maintain

maximum control of our emissions. These policies are not unrealistic to

manufacturers. It is important to keep our environment clean, and the
emissions

we produce can do great amounts of damage.