EPA-450/2-75-009 b
STANDARD SUPPORT
AND
ENVIRONMENTAL IMPACT STATEMENT
VOLUME 2: PROMULGATED ,
EMISSION STANDARD
FOR
VINYL CHLORIDE
Emission Standards and Engineering Division
U. S. Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
September 1976
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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are
available free of charge to Federal employees, current contractors and
grantees and nonprofit organizations - in limited quantities - from the
Library Services Office (MD-35) , Research Triangle Park, North Carolina
llll-L °T B f ' m the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia 22161.
Publication No. EPA-450/2-75-009b
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Final Standard Support and Environmental Impact Statement
Vinyl Chloride Emissions from Ethylene Dichloride-
Vinyl Chloride and Polyvinyl Chloride Plants
Type of Action: Administrative
Prepared by
Director, Emission Standards and Engineering Division
Environmental Protection Agency
Research Triangle Park, N. C. 27711
(Date)
Approved by
(Date)
Assistant Administrator for Air
and Waste Management
Environmental Protection Agency
401 M Street, S. W.
Washington, D. C.
Final Statement Submitted to Council on Environmental Quality
on
_October 1976
(Date)
Additional copies may be obtained at:
Public Information Center (PM-215)
Environmental Protection Agency
Washington, D. C. 20460
m
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Table of Contents
Page
Chapter 1. Summary of the Environmental Impact of the
Emission Standard for Vinyl Chloride 1-1
Chapter 2. Summary of Public Hearing and Comments . . 2
2.1 List of Commentators. . 2-1
2.2 Rationale for Regulating Vinyl Chloride
Under the Authority of Section 112 of
the Clean Air Act ...... 2-5
2.2.1 Decision to List Vinyl Chloride as
a Hazardous Air Pollutant m 2-5
2.2.2 Approach for Regulating Vinyl
Chloride Under Section 112 2-17
2.3 Selection of Source Categories ..... 2-28
2.3.1 §61.60 ............ 2-28
2.4 Emission Limits
............. • • • 2-33
2'4'1 ^M2!a)' 61-63(a)> and 61.64(a)(l), 9 „
(b), (c)9 and (d) ....... , ^~66
2.4.2 §61.62(b)
........... ... 2-36
2.4.3 §61.64(a)(2)
.............. 2-37
2.4.4 §61.64(e) ............ ^ 2^38
2.4.5 §61.65(a) ........... 2_47
2.4.6 §61.65(b)(l) .... ....... 2-50
2.4.7 §61.65(b)(3) ........... 2_52
2.4.8 §61.65(b)(4) ... ........ 2-54
2.4.9 §61.65(b)(5) ...
....... ... £-00
2.4.10 §61.65(b)(6). . ............ 2_58
2.4.11 §61.65(b)(7) .
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Page
2.4.12 §61.65(b)(8) "•"•'. • • • • . 2-61
2.4.13 §61.65(b)(9) ......... 2-64
2.4.14 §61.66 2-6C
2.5 Testing, Reporting, Recordkeeping 2-67
2.5.1 §61.67 2-67
2.5.2 §61.68 2-70
2.5.3 §61.69 2-71
2.6 Test Methods 2-73
2.7 Economic Impacts 2-82
2.8 Environmental Impacts 2-94
2.9 Process and Control Technology (Chapters
3 and 4 of Volume I of the Standard
Support and Environmental Impact
Statement) ........... 2-'01
2.10 Comments on Quantitative Risk Assessment
for Community Exposure to Vinyl
Chloride 2-107
2.11 Miscellaneous 2-112
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CHAPTER I. SUMMARY OF THE ENVIRONMENTAL IMPACT
OF THE EMISSION STANDARD FOR VINYL CHLORIDE
Background: On December 24, 1975, the Environmental Protection Agency
(EPA) proposed a national emission standard for vinyl chloride under
the authority of section 112 of the Clean Air Act. At that time, EPA
requested public comments on the proposal. Fifty comment letters were
received from environmental groups, industry, State and local air
pollution control agencies, and individual citizens. On February 3, 1976,
EPA held a public hearing on the proposed standard in Washington, D. C.
Both the written comments and the comments made at the public hearing as
well as EPA's responses to these comments are summarized in this document.
The summary of comments and responses serves as the basis for revisions
which have been made to the standard between proposal and promulgation.
EPA decided to regulate vinyl chloride because it has been implicated
as the causal agent of angiosarcoma and other serious disorders, both
carcinogenic and noncarcinogenic, in people with occupational exposure
and in animals with experimental exposure to vinyl chloride. Reasonable
extrapolations from these findings cause concern that vinyl chloride may
cause or contribute to the same or similar disorders at present ambient
air levels. The purpose of the standard is to minimize vinyl chloride
emissions from all known process and fugitive emission sources in
ethylene dichloride-vinyl chloride and polyvinyl chloride plants to the
level attainable with best available control technology. This will have
the effect of furthering the protection of public health by minimizing
the health risks to the people living in the vicinity of these plants
and to any additional people who are exposed as a result of new construction.
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Alternatives to the Proposed Action: The alternatives to the proposed
action are discussed in detail in Chapter 5 of Volume I of the
Standard Support and Environmental Impact Statement (SSEIS, Vol. I.).
These alternatives concern the quantity of energy required to incinerate
the emissions from the oxychlorination process in ethylene dichloride-
vinyl chloride plants and the degree to which EPA should require
developing technology for controlling emissions from the processing of
dispersion resins in polyvinyl chloride plants. These alternatives
remain unchanged since the standard was proposed.
Environmental jmgact of the Standard: Changes in the standard since
proposal do not affect the level of control required. Therefore, the
environmental impacts for the promulgated standard and alternative •
control levels are essentially the same as described for the proposed
standard in Chapters 1 and 6 of the SSEIS, Vol. I. There is one exception.
Based on data submitted by the Society of Plastics Industry, Inc. (SPI),
the impact on water consumption (SSEIS, Vol. 1) was overstated. In-
estimating the impact on water consumption, EPA based its -estimates on
worst case conditions. That is, EPA assumed that those control systems
with the greatest water usage would be employed and that there would be
no recycling of water. There is no regulation which would require water
recycling. According to SPI, the control system utilizing the most
water will not be used generally by the industry and economics will
cause plants to recycle much of the water. Therefore, the impact of the
standard on water consumption will be negligible. A more detailed
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discussion of the water consumption impact can be found in the first
comment in Section 2.8 of Chapter 2 of this document.
A summary of the environmental impact of the promulgated standard
is as follows:
The primary environmental impacts of the standard are beneficial
and will consist of reductions in vinyl chloride emissions from
ethylene dichloride-vinyl chloride and polyvinyl chloride plants,
and consequently, corresponding reductions in ambient air concentrations
of vinyl chloride and risks to health in the vicinity of these sources.
Although the standard will not eliminate all vinyl chloride emissions,
it will further the protection of public health by minimizing emissions.
For a typical average-sized ethylene dichloride-vinyl chloride plant,
the standard will reduce hourly vinyl chloride emissions from 176 kg to
10 kg. This is approximately a 94 percent reduction. For a typical
average-sized polyvinyl chloride plant, the hourly vinyl chloride
emissions will be reduced from 330 kg to 16 kg, or by approximately
95 percent. Percentage numbers for both source categories are based
on an estimated 90 percent reduction in fugitive emissions and 1974
emission levels.
There are several potential secondary environmental impacts
of the standard. These include increased atmospheric emissions of
hydrogen chloride, lowered pH of inprocess wastewater due to hydrogen
chloride, small increases in the quantity of vinyl chloride released
into inprocess wastewater, increased solid waste disposal due to
carbon used for adsorption, and increased energy consumption. The
types and degree of the secondary impacts resulting from the standard
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will vary from plant to plant depending on the type of control
selected to meet the standard.
The potential secondary environmental impacts of the standard
are either insignificant or will be minimized without additional
action, except for one adverse impact. Hydrogen chloride is already
emitted by process equipment at ethylene dichloride-vinyl chloride
plants and by other petrochemical, plants in the complexes where
ethylene dichloride-vinyl chloride plants are typically located. An '
incinerator used to attain the standard at an ethylene dichloride-vinyl
chloride plant could increase hydrogen chloride emissions by several fold.
Typically, however, due to the corrosion problems which would otherwise
occur both on plant property and in the community, plants use scrubbers •
to control already existing hydrogen chloride emissions. Hydrogen
chloride emissions resulting from control of vinyl chloride emissions
are expected to also be controlled for the same reason. If even a
moderately efficient scrubber (98 percent control) were used to control
the hydrogen chloride emissions resulting from incineration of vinyl
chloride emissions, the increase in hydrogen chloride emissions from a
typical ethylene dichloride-vinyl chloride plant due to the standard
would be reduced to 35 percent. However, EPA plans to further evaluate
the need to control hydrogen chloride emissions, since diffusion model
results indicate that under "worst-case" meteorological conditions, the
hydrogen chloride emissions from the process equipment and the incinerator
combined would cause maximum ambient concentrations of hydrogen chloride
in the vicinity of ethylene dichloride-vinyl chloride plants to be in
the same range or somewhat higher than existing foreign standards and
National Academy of Sciences (NAS) guidelines for public exposure.
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Economic Impact of the Standard: In accordance with Executive Order
11821 and OMB Circular A-107, EPA carefully evaluated the economic and
inflationary impact of the proposed standard and alternative control
levels. The economic analysis is contained in Chapter 7 of the SSEIS,
Vol. I. Since changes in:the standard since proposal do not affect the
level of control required, the economic impacts of the promulgated
standard and alternative control levels are essentially the same as
described for the proposed standard. There is one exception. EPA
estimated that there would be four plant closures as a result of the
promulgated standard. Of the four plants identified as possible
closure candidates, one (Occidental Petroleum Corporation's polyvinyl
chloride plant in Hicksville, N. Y.) has given notice that it no longer
produces polyvinyl chloride, and the other three (Jennat Corporation's
plants in Somerset, N. J., Torrence, Calif., and Tucker, Ga.) have
indicated that they do riot intend to close as a result of the standard.
A summary of the economic impact of the promulgated standard is
as follows:
The total capital cost for existing plants to meet the standard
is estimated to be $198 million, of which $15 million is for ethylene
dichloride-vinyl chloride plants and $183 million is for polyvinyl
chloride plants,. EPA estimates that these plants will have to spend
$70 million per year to maintain the required emission levels. In
addition, total capital cost for existing plants to meet the EPA's 1983 water
effluent guideline limitations is $83 million and the total annualized
operating cost is $17 million. The costs to the industry of meeting
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the OSHA standard cannot be quantified at this time, but they are
expected to overlap to some degree with the costs to meet EPA's
fugitive emission regulations. The costs of meeting the fugitive
emission regulations are included in the total costs cited
above for meeting the promulgated regulation. Broken out separately,
the capital cost of meeting the fugitive emission regulations is
$37 million and the annualized cost is $25 million.
The promulgated standard is not expected to deter construction
of new ethylene dichloride-vinyl chloride plants or most types of
new polyvinyl chloride plants. For one type of polyvinyl chloride
plant (dispersion process) that represents 13 percent of the industry
production, the standard would significantly deter the construction
of smaller plants.
It is estimated that the price of polyvinyl chloride resins
would rise by approximately 7.3 percent in order to maintain
precontrol profitability and also to recover the total annualized
control costs necessitated by the standard at ethylene dichloride-
vinyl chloride plants and polyvinyl chloride plants. This increase
is estimated to translate into a maximum consumer price increase in
goods fabricated from polyvinyl chloride resins of approximately
3.5 percent. Recovery of effluent annualized costs plus maintenance
of precontrol profitability is estimated to add approximately 2
percent to polyvinyl chloride resin prices and result in an additional
maximum consumer price increase of 1 percent.
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Relationship -Between Local Short-Term Uses of Man's Environment
and the Maintenance and Enforcement of_ Long-Term Producti on: By
taking steps now to establish standards based on best available
control technology to minimize vinyl chloride emissions, EPA will be
able to minimize exposure and prevent severe illnesses and deaths
which may have occurred in future years as a result of prolonged
community exposure to vinyl chloride. Therefore, the standard
may curtail industrial expansion on a short-term basis, as a
result of funds being diverted from support of industrial expansion
to support of installation of process changes and control systems to
attain the standard; but it will enhance the long-term productivity
of man and his environment.
Irreversible and Irretrievable Commitments of Resources: Irreversible
and irretrievable resources which would be committed to reduce ambient
concentrations of vinyl chloride include energy and the materials
to construct incinerators, boilers, monitoring equipment, carbon
adsorption units, etc. If incineration were used to meet the
standard, additional energy and materials would be needed for
operation of an absorption unit to abate hydrogen chloride emissions.
1-7
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CHAPTER 2
SUMMARY OF PUBLIC HEARING AND COMMENTS
2.1 List of Commentators
Comment No.
VC-1
VC-2
VC-3
VC-4
VC-5
VC-6
VC-7
VC-8
VC-9
1 VC-10
vc-n
VC-12
VC-13
VC-14
Commentators
Robert A. Fine
Hooker Chemical Corporation
Constance Panchuk
PARKLABREA
Mr. and Mrs. F. B. Minnock
(U. S. Resident)
Marilyn E. Sadowski
(U. S. Resident)
Dr. Martin Wersba
(U. S. Resident)
Dr. John F. Finklea
National Institute for Occupational
Safety and Health
Susan Howard
(U. S. Resident)
Gayle and Herb Weaver
(U. S. Resident)
Dr. Peter F. Infante
National Institute for Occupational
Safety and Health
June Armstrong
(U. S. Resident)
Robert H. Collom, Jr.
Department of Natural Resources (Georgia)
Harry H. Hovey, Jr.
N. Y. State Department of Environmental
Conservation
R. W. Laundrie
The General Tire and Rubber Co.
R. E. Hiding
PPG Industries, Inc.
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Comment No.
VC-15
VC-16
VC-17
VC-18
VC-19
VC-20
VC-21
VC-22
VC-23
VC-24
VC-25
VC-26
VC-27
VC-28
VC-29
VC-30
Commentators
Allan J. Topol
Covington & Burling (for Tenneco Chem.)
Ed Light
West Virginia - Citizen Action Group
F. V. Prus
The Goodyear Tire and Rubber Co.
David A. Kuhn
Continental Oil Co.
Flynt Kennedy
Continental Oil Co.
Lee E. Jager
Department of Natural Resources (Michigan)
W. W. Madden
Firestone Plastics Co.
W. C. Holbrook
B. F. Goodrich Chemical Co.
Barry I. Castleman
Environmental Defense Fund
Harvey A. Rosenzweig
Borden, Inc.
R.. N. Wheeler, Jr.
Union Carbide Corporation
J. M. DeVoe
Allied Chemical
R. E. Van Ingen
Shell Chemical Co.
Gary L. Ford
Stauffer Chemical Co.
Ralph L. Harding, Jr.
The Society of the Plastics Industry, Inc.
Earl R. Smith
Dow Chemical U.S.A.
2-2
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Comment No.
Commentators
VC-31
VC-32
VC-33
VC-34
VC-35
VC-36
VC-37
VC-38
VC-39
VC-40
VC-41
VC-42
VC-43
VC-23a
VC-44
Robert W. Hill
Diamond Shamrock Corporation
Richard Fleming
Air Products and Chemicals, Inc.
R. A. Abramowitz
R. A. Fine
Hooker Chemical Corporation
Mitchell R. Zavon, M.D.
Ethyl Corporation
John C. White
EPA - Region VI
Jack Jaglom
The Pantasote Company of New York, Inc.
Professor Benjamin Linsky
West Virginia University
Sidney M. Wolfe, M.D.
Health Research Group
Kip Hewlett ,
Georgia-Pacific Corporation
Keysor-Century Corporation
John M. Daniel, Jr.
State Air Pollution Control Board (Virginia)
Charles R. Barden, P.E.
Texas Air Control Board
Dr. Thomas A. Robinson
Vulcan Materials Co.
Barry I. Castleman
Environmental Defense Fund
George P. Ferreri
Bureau of Air Quality and Noise Control
(Maryland)
2-3
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Comment No.
VC-45
VC-46
VC-47
VC-48
VC-49
VC-50
Commentators
James F. Coerver
Louisiana Air Control Commission
Sidney R. Galler
U.S. Department of Commerce
James C. Miller.Ill
Council on Wage and Prfce Stability
Stephen C. Urman
Occupational Safety and Health
Administration
Stanley D. Doremus
U.S. Department of the Interior
Edward F. Ferrand
Environmental Protection Administratiop (N.Y.)
Chapter 2 contains a summary of the public comments on the
proposed standard and EPA's responses to them. The comments are
divided into sections. The first section discusses the rationale
for regulating vinyl chloride under the authority of section 112
of the Clean Air Act; i.e. EPA's decision to list vinyl chloride
as a hazardous air pollutant and the approach used for regulating
vinyl chloride under section 112. The next three sections discuss
the selection of source categories, the emission limits, and
testing, reporting, and recordkeeping requirements. The comments
in these three sections are organized to correspond with the
different^section numbers in the proposed standard. The remaining
sections include comments on the test methods, economic and environ-
mental impacts, process and control technology, and the Quantitative
gjsk Assessment for Community Exposure to Vinyl Chloride. Comments
" ... Scient'lf'lc a"d Technical Assessment Report for Vinvl Chloride
£2imnyl Chloride are included in section 2.27Ton~EPA's decision
ist vinyl chloride as a hazardous air pollutant
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2.2 Rationale for Regulating Vinyl Chloride Under the Authority
of Section 112 of the Clean Air Act.
2.2.1. Decision to List Vinyl Chloride as a Hazardous Air Pollutant.
(Except for commentators VC-32, VC-23, and VC-46, the comments
contained in this section generally did not contest EPA's decision to
list vinyl chloride as a hazardous air pollutant. However, they did
argue that EPA has placed great and sometimes unwarranted emphasis on
factors suggesting the possibility of a health risk while "playing down"
or not even mentioning factors which suggest that there may be no
significant risk at all. Examples cited by the commentators are listed
below).
1. VC-22, VC-27, VC-29, VC-32
Comment: The U. S. worker EPA discussed as having been exposed
to vinyl chloride levels lower than those usually encountered in
polyvinyl chloride production has been dropped from the National Institute
of Occupational Safety and Health's listing of workers with angiosarcoma.
Response: Table 6.18, page 73, of the Scientific and Technical Assessment
Report (STAR) includes the data which were available at the time of
publication, documented by the Center for Disease Control. Dr. John T. Herbert,
Center for Disease Control,, was contacted by telephone on March 29, 1976.
Dr. Herbert, on that date, stated that the information in Table 6.18,
including the footnotes was still correct. He also stated that four
additional cases from Canada had been added to the list. There are
questions concerning the level of exposure of those cases not involved
directly in polyvinyl chloride and vinyl chloride production, and in
some cases the pathology. These uncertainties are stated in the appropriate
footnotes to table 6.18. However, in spite of these uncertainties, in
view of the possible exposure patterns, these cases cannot be ignored in
the evaluation of the potential public health problems.
2. VC-22, VC-29, VC-27, VC-32, VC-46
Comment: EPA has not summarized the results from the more extensive
ambient monitoring program but stated that the results from the more
extensive ambient monitoring program are generally in the same range
as found in previous studies except for peak concentrations. The more
recent data actually show significantly lower ambient concentrations
of vinyl chloride than previously measured.
Response: A report entitled "EPA Programs of Monitoring Vinyl Chloride
in Ambient Air" summarizing the data from the more extensive monitoring
program was made available by EPA. A detailed analysis comparing the
results from the two monitoring programs has not been performed by EPA.
The sampling procedures, placement of samplers, extent of sampling, and
quality of analysis were not the same in the two programs. Only one of
the plants monitored in the second program was also monitored in the
first program.
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3. VC-22, VC-29
Comment: EPA has stated that "Occupational exposure studies have
strongly implicated vinyl chloride as a human chemical carcinogen ...".
It should be noted that these studies were conducted at relatively high
levels compared to ambient concentrations now being detected.
Response: _It is still true, however, that occupational exposure studies
do indeed implicate vinyl chloride as a human carcinogen which manifests
itself in liver angiosarcoma, and suggest that it may also manifest
itself in multiple tumor sites. Because of the rarity of angiosarcoma, .
the cause-effect relationship has been clearly demonstrated. Vinyl chloride
is one of the few industrial carcinogens for which confirmatory animal
studies have been positive.
4. VC-22, VC-27, VC-29, VC-32, VC-36
Comment: The preamble and Volume I of the Standard Support and
Environmental Impact Statement (SSEIS, Vol. I) refers to "some occasional
PeaFconcentrations as high as 33 ppm." The STAR document correctly
states that there was one instantaneous value of 33 ppm which was
f SaTd f a d1Sta^C5 ?f °'5 km from the center of thPe plant and
saS, V?irf?rJX fShedJ. P,PnU The data from the 24-hour integrated
1974 study/' 9 ValUe t0 be °'55 ppm for the N°vember
Response^ Jhere was only one peak value of 33 ppm and it occurred
5. VC-22
Comment: EPA states that approximately 4.6 million people live within
a 5-mi lie radius of ethylene di chloride/vinyl chloride and polyvinyl
hll2r«JnISn!! !CtU""? Cities. The implication that these people are
being exposed to vinyl chloride is questionable. The basis for using a
5-mile radius is questionable since EPA has done no sampling beyond a
rnl le-Ia rUS- Accord,!n9 to the "Quantitative Risk Assessment for
Community Exposure to Vinyl Chloride," approximately 1.7 million
people live within a 3-mile radius of such plants.
Response: Dispersion model calculations indicate that vinyl chloride
hSSS £atTS-?f 91ater than ] part Per b1111on (PPb) can be found
beyond the 5-mile radius. The five miles was chosen as a practical
matter since population estimates were available for that distance.
The average concentration calculated depends only slightly on radius.
6. VC-22, VC-32, VC-46
t0 the Pr°P°sed standard and in Chapters 1 and
1S Stated that "^asonable extrapolations
™Hh C°"C?rn that Vlnyl chlon'de may cause, or may
contribute to, the same or similar disorders ...". There is no reference
nor6?* ?npr???rtH^e^lain/5a^ suct! reasonable extrapolations were, .
nor is specific data presented to substantiate such concern.
2-6
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Response: Section 112 of the Clean Air Act defines the term "hazardous
air pollutant" as "an air pollutant to which no ambient air quality
standard is applicable and which in the judgment of the Administrator
may cause, or contribute to, an increase in mortality or an increase
in serious irreversible, or incapacitating reversible, illness."
The sentence in question refers to the factors the Administrator considered
in his judgment that vinyl chloride should be listed as a hazardous air
pollutant. These factors include:
(1) Data from occupational exposure studies indicate that
vinyl chloride is a carcinogen, and possibly a mutagen and teratogen.
(2) Data from animal exposure studies demonstrate that vinyl
chloride is a carcinogen and a teratogen.
(3) Data from microbial systems indicate that vinyl chloride
is a mutagen.
(4) Vinyl chloride has been measured in communities surrounding
ethylene dichloride-vinyl chloride and polyvinyl chloride plants.
(5) The threshold for effects has not been demonstrated. In
absence of proof to the contrary, EPA believes that it is prudent to
assume that there is no no-effect level.
(6) There is an expected latency period of 20 years or more from
the time of community exposure to vinyl chloride and the appearance of
effects.
7. VC-17, VC-22, VC-27, VC-29, VC-32, VC-46. Public Hearing Record-
Presentation of P. J. Gehring of Dow Chemical, p. 87.
Comment: EPA has implied that vinyl chloride is "an apparent non-threshold
pollutant." Laboratory data on metabolism has been developed under
Manufacturing Chemists Association administered research study. The
data indicate that there are at least two different metabolic routes for
destroying vinyl chloride, and therefore, raise questions as to the
validity of the EPA stated assumption.
Response: The results of the recent studies by Dr. P. J. Gehring are
indeed significant; however, they are not sufficient to resolve the
issue of a biological threshold, or to establish such a value. Dr. Gehring's
studies reflect a short-term response to relatively high levels of
exposure (one hour of 50-1,000 ppm). Studies by Dr. Selikoff on industrial
workers exposed to vinyl chloride for more than five years reveal that
the substance bioaccumulates, and is not excreted or otherwise metabolized
after five weeks of non-exposure. Thus, one short-term response to high-
level exposure is irrelevant in terms of long-range responses to chronic
low-level exposure.
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8. VC-27
Comment: Human cases of cancer alleged to be associated with vinyl
A^^^r^n" S!e U1ted States are 1im1ted to only foL
-------
Response: The statement from the Quantitative Risk Assessment for
Community Exposure to Vinyl Chloride is taken out of context. The
following is an extract from the subject document:
"This survey has produced no evidence that living around vinyl
chloride plants is a factor in the occurrence of liver angiosarcoma.
This conclusion is far different than saying that living around plants
is not a risk factor for several reasons: (1) This type of survey
of a disease with a latent time from first exposure to diagnosis of
17 years reflects exposures that started at some time before 1957, when
the quantities of vinyl chloride produced were much smaller than the
current production levels. (2) This survey did not include the
place of occupation of the currently suspected collection of liver
angiosarcoma cases. Therefore, it underestimates the risk of being near a
vinyl chloride plant. (3) This survey might not have detected all
existing liver angiosarcoma cases, although the number we have is
consistent with the national statistics. The circumstantial evidence for
this is that there was not substantial overlay between the three sources
of case information. If the data sources had been complete, the
information collected by CDC from the National Center for Health
Statistics would contain all the cases reported by both the Armed Forces
Institute of Pathology arid the state health department. (4) In over
90 percent of the cases traced in this survey, the only information
available was the residence at the time of death and in some cases, the
residence of the spouse or parent only. This information is only a
crude indication of where the individuals spent most of their lives.
(5) In contrast with our expectation when the survey was started, there
is a significant rate of changes in diagnosis after the slides are
confirmed by the National Cancer Institute. The 286 cases currently
on file cannot be regarded as definitely established liver angiosarcoma.
11. VC-22, VC-32
Comment: Chapter 6 of the STAR document includes an extensive
bibliography on vinyl chloride monomer toxicology and epidemiology.
There are at least three additional scientific documents which have
become available that are pertinent and should be made a part of the
EPA hearings docket.
(a) "Report on Mortality Data Collected by Organization
Resources Councilors, Inc., Concerning the Effects of Vinyl Chloride
Exposure in PVC Fabrication." (Available from ONC, 1625 I Street, N. W.,
Washington, D. C. 20006).
(b) "Metabolic Studies in Vinyl Chloride as a Function of Concentration"
by Dow Chemical Company under Manufacturing Chemists Association administered
research study. (Available from MCA, 1835 Connecticut Avenue, N. W.,
Washington, D. C. 20009).
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(3) "Inhalation Toxicity of Vinyl Chloride" by Industrial Bio-
Test Laboratories, Inc., under Manufacturing Chemists Association administered
research study. (Available from MCA, 1825 Connecticut Avenue, N. W ,
Washington, D. C. 20009).
Response: It is stated in the Preface of the STAR-document that
information available through June 1, 1975, was generally considered,
and further that references cited did not constitute a complete
bibliography. The more recent references cited by the commentator are
pertinent, and are incorporated into the bibliography by referencina
them in this document.
12. VC-46
Comment: There are speculative statements made by EPA which should be
qualified as such. EPA stated that the "latency period can possibly be
longer for lower levels of exposure." Also that "EPA will be able to
reduce substantially the risks, that severe illnesses and deaths will
occur in the future as a result of the present and prolonged community
exposure to vinyl chloride."
Response: In the first sentence, the words "can possibly" qualify the
sentence so that a reader would not think that there is proof that the
latency period would be longer for lower levels of exposure. The second
sentence states that the EPA regulation would decrease risk of severe
illness and not necessarily the severe illness.
13. VC-46
Comment: The terms "non-threshold pollutant" and "apparent non-
threshold pollutant" are not proper and are inappropriately applied to
vinyl chloride.
Response: The paragraph referred to explains that data are available
which make it clear that vinyl chloride is hazardous within the definition
of section 112 at higher levels of exposure. However, since there are
no dose-response data on health effects of vinyl chloride at lower
levels of exposure (below 50 ppm), a threshold level of effects cannot be
defined for exposure levels of vinyl chloride found in the ambient air.
There is no conclusive evidence that there is a threshold concentration
of vinyl chloride below which cancer does not occur. Therefore as a
matter of prudence, EPA assumes that some risk exists for any level
of vinyl chloride exposure, and proposes to reduce this risk with the
current regulation.
14. VC-21, VC-26, VC-27, VC-29, VC-32, VC-34
Comment: EPA has not taken sufficient cognizance of either the cost of
or the improvements from, efforts made to comply with the Occupational
Safety and Health (OSHA) standard. A principle reason these effects are
uncertain is that the Agency has made no effort to measure them. Some
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of the efforts are complimentary, others are totally separate, and the
costs are not altogether overlapping. Ventilation contributes only an
insignificant reduction in the vinyl chloride levels in the work place
and, therefore, any concern that the emissions found in 1974 would
continue are completely unfounded. Any justification as to the need for
an emission reduction should be based on those emissions found after
completion of all projects designed to comply with the OSHA regulation.
Response: EPA stated in the preamble to the proposed standard
t'hat the OSHA standard is expected to "indirectly reduce atmospheric
emissions to some degree, but that the degree is unknown. In the
SSEIS, Vol. I, the reason that the degree is unknown is explained. The
OSHA standard requires that employee exposure be reduced to 1 ppm. It
does not prescribe the means for doing this. It does require that
employers institute feasible controls to the fullest extent possible and
to continue to improve and apply engineering controls until full compliance
is achieved. Some of the engineering controls used to meet the OSHA
standard can also be used to meet EPA's standard. Since a plant owner
knows both what OSHA and EPA expect he can plan so that he can use some
of the same controls to meet both standards. OSHA did not prescribe any
deadlines for compliance through engineering controls. The plants are
expected to use some combination of respiratory protection, ventilation
techniques, and emission reduction. The plants are not expected to be
uniform in what they use. OSHA does not require submittal of a formal
plan describing what the plants plan to use. Therefore, in order to
find out how much emission reduction the OSHA standard is achieving, EPA
would have to send to each plant a request for information on the
controls they are using, the controls they plan to use, and how much
these controls will reduce emissions. This does not seem to be necessary,
since it is not likely to change EPA's standard. If the plants are
using engineering controls rather than ventilation and respiratory
protection to meet the OSHA standard, this is achieving both OSHA and
EPA goals. On plant visits EPA has observed that engineering controls
have been employed to a large extent, but that ventilation practices are
still employed to some extent. An example would be open-sided buildings.
With regard to cost, EPA has always been interested in
obtaining figures on the cost of the OSHA standard. During the
February 3, 1976, public hearing Susan Wyatt of EPA asked Ralph Harding .
of the Society of Plastics Industry (SPI) how much of the cost to meet
EPA's standard can also be attributed to meeting the OSHA standard.
(Public Hearing Transcript, p.69). Mr Harding replied that he did not
know and that it is a premature number at this time. He continued by
saying that he thought they were interrelated, but that he didn't think
the industry was ready to ascribe "which costs to which standard." In
order to get information on the costs of the OSHA standard, EPA would
have to request each plant to submit cost figures for both present and
future controls. The benefits from this exercise are not apparent.
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15. VC-21, VC-32, VC-34
Comment: Ventilation used to meet the OSHA standard dilutes emissions
and decreases ambient concentrations.
Response: Ventilation can reduce ambient concentrations, although
not necessarily. An example would be an open-sided building EPA
considers^technology for reducing emissions as a more reliable method
for reducing ambient concentrations.
16. VC-27, VC-29, VC-32, VC-34
The emission levels reported in the supporting documents are
overstated. Fugitive emissions in particular are overstated
because they are based on a materials balance and because poly-
vinyl chloride solids were incorrectly included in the fugitive
vinyl chloride losses. The fugitive emissions reported for 1974
have been substantially reduced since that time because of the
OSHA standard. Stack emissions have also been reduced since 1974
These overstated emission levels were used in diffusion calculations,
and so the maximum ambient concentrations reported by the diffusion
model are also overstated.
Furthermore, the maximum ambient concentrations do not
present a realistic picture of what is occurring around the
plants. Worst conditions are assumed in the modeling. The maxima
occur within 80 to 220 meters of the model plants which is still
well within the plant limits for all but the smallest plants.
Response: All emission levels reported in the preamble and supporting
documents are based on 1974 data. This qualification is stated in
all places where emission data are presented. EPA recognizes that
emissions have been reduced since that time, and has so stated in
the preamble to the proposed standard. EPA has decided not to gather
more recent data on emission levels, because these emission levels
are expected to continue to change, and gathering the data would take
considerable time both on the part of EPA and on the part of industry.
Since the purpose of the standard is to minimize emissions, these
more current data would not affect the standard itself. In other words,
|PA_s purpose is to apply best control technology, not to reduce
fugitive emissions by 90 percent. More current data on emission levels
would reduce the relative impact of the standard on the ambient air
concentrations which are presented in the chapter on environmental
impacts. All diffusion modeling data contained in the environmental
impact chapter are qualified by stating that they are based on 1974 data.
t EPA did include polyvinyl chloride solid losses in the fugitive
emission estimates. This was based on a discussion with plant
engineers from one company who described unaccounted for polyvinyl
chloride losses as "very, very small." The fugitive emission estimates
include only unaccounted for polyvinyl chloride losses. In EPA's
judgment polyvinyl chloride solid losses are more easily accounted
2-12
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for than vinyl chloride gaseous losses. Polyvinyl chloride collected
in baghouses or cyclones can be weighed. The efficiencies of these
collection devices are known, so the loss from them can be calculated.
Polyvinyl chloride discharged into wastewater settles out and can be
weighed. This is not true for vinyl chloride gas. If it were assumed
that 50 percent of the emissions were solid as was suggested by the
commentator, a typical 68 million kilogram per year plant would lose
nearly 2000 kg of polyvinyl chloride per day. Because polyvinyl chloride
losses are more easily accounted for, they are considered to be lower
than this. Thus, EPA assumed that all unaccounted for losses were vinyl
chloride monomer.
With regard to diffusion modeling, it seems reasonable to
estimate the worst atmospheric concentrations that are to be
expected. It should be emphasized that these estimates were
based on worst, but realistic conditions. Eighty to 220 meters
from the center of the plant would in many cases be on plant
property. At one plant that was monitored, a sampler was located
across the street from a plant and was about 200 meters from the primary
emission point. In EPA's modeling, all emissions were assumed to
occur from the center of the plant property. In fact, emission
sources, particularly at polyvinyl chloride plants are located
more diffusely on the plant property. Fugitive emission sources,
in particular, are likely to be located closer to plant property
lines than assumed. For this reason they may have a larger impact
outside of the property lines than indicated by the diffusion.modeling.
Although the estimated maximum concentrations of vinyl
chloride were given in the SSEIS, Vol. I, EPA also states in the
Quantitative Risk Assessment Document that an average exposure of 17 ppb
was estimated to exist within a 5-mile radius of an average plant. This
figure was also based on 1974 emission levels.
17. VC-32, VC-34, VC-46
Comment: Available health data are not sufficient to justify
regulating vinyl chloride under section 112. Section 112 of the
Clean Air Act allows the Administrator to regulate those
substances which may cause or contribute to an increase in
mortality, or an increase in serious irreversible or incapacitating
reversible illnesses. In the case of vinyl chloride, none of these
requirements had been reported outside of the plant which can be traced
directly to any plant or to any manufacturing use of vinyl chloride
or the formation of polyvinyl chloride products.
Response: As implied by the commentator, no community cases of
angiosarcoma have been verified as being caused by ambient
exposure to vinyl chloride. Thus, there is no proof that vinyl
chloride ambient concentrations cause cancer, teratogenesis, and
mutagenesis. The data base showing that vinyl chloride causes
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these effects as a result of occupational exposure is a very strong
one. The latency period for developing cancer due to vinyl chloride
exposure is indicated to be at least 20 years. Section 112 defines
a hazardous pollutant as one which "may cause or contribute to "
(emphasis added) rather than one which has been proven to cause""
or contribute to certain effects. As stated in the preamble to
the proposed standard, EPA has concluded that it should take action now
to reduce exposure levels to vinyl chloride before retrospective
evidence of risk is allowed to show itself.
18. VC-32
Comment: Standards for vinyl chloride should be set under the
authority of section 109 or 111 of the Clean Air Act. Although
the preamble to the proposed standard asserts that section 109 treatment
of vinyl chloride would be inappropriate "because vinyl chloride is a
localized problem and section 109 is usually more appropriate for
regulating pollutants whose presence in the ambient air is ubiquitous,"
;EV5i!ence ?f Clusten'n9 °f incidences of liver angiosarcoma demonstrates
that the problem is not localized. Moreover, the recent joint
publication of the American Health Foundation and the National Cancer
Institute suggests that vinyl chloride may well be ubiquitous
in the ambient air because of the combustion of vegetation.
EPA has implicitly accepted that an ambient concentration aot
exceeding 1 ppb vinyl chloride is sufficient to provide an ample
margin of safety to the public health. An ambient air standard under
section 109 to this effect would properly protect the public We
also support an appropriate new source standard for vinyl chloride
under section 111.
Response: The reason for not using section 109 is not related to
whether there is a clustering of angiosarcoma cases. Section 109
is usually not used for pollutants which are emitted from a
relatively small number of source types of which there are a
n;la*uVel£ t^plants< EPA has stated that it d°es not know what
the threshold level of effects for vinyl chloride is, and thus does
hot know what level would provide an ample margin of safety.
EPA has left open the option of setting standards in the
future for new sources under section 111. Such standards could
require increased control of the oxychlorination process or more
stringent stripping limitations. As an alternative to section 112,
however, EPA concluded that section 111 is not the best mechanism
for controlling vinyl chloride. Specifically, the length of time
required under section lll(d) from State to State, State-granted
variances that may be based only on cost considerations, and standard
development as a State rather than a Federal process are all
features that make section 111 unacceptable for a substance
which fits the definition of a "hazardous air pollutant."
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19. VC-6
Comment: "This letter is in regard to the most recent assessment
of health problems which may follow exposures to vinyl chloride. It
is our hope that this assessment may be of some assistance to your
Agency in discussion of standards to limit vinyl chloride emissions
into the ambient air. Two studies that are conducted by NIOSH and CDC
personnel which directly bare on this issue of community effects are
those which Dr. Infante of NIOSH performed while he was at the Ohio
Health Department and subsequent investigations by the Division of
Cancer and Birth Defects of the Bureau of Epidemiology in Atlanta.
Enclosed are copies of these two studies.
"Our scientists may differ in their interpretation of particular
studies in relation to vinyl chloride exposure and teratogenesis.
They are, however, in complete agreement that while the issue is not
yet resolved, the potential public health ramifications remain a cause
for concern. Please note that we are speaking only of vinyl chloride
monomer-VCM, and not of polyvinyl chloride plastic.
"The points raised in conversations with your office dealt specifically
with the issue of teratogenicity of VCM among humans. Neither the
Infante nor the CDC study resolve the matter. Dr. Infante's study used
available birth and fetal death record information and identified three
areas with increased rates of central nervous system malformations.
The CDC investigation followed up cases in one city and found no
parental association between VCM exposure and plant employment. There
also appeared to be no differences between cases and controls with
respect to location of residence relative to the plant in Painesville.
In this circumstance no association could be established with VCM.
However, the authors stated, "This study clearly does not rule out the
possibility that vinyl chloride may be teratogenic." Because of the
small numbers of cases involved, there still might be an effect that
was not detectable in Painesville.
"It is important to remember that the possible effects of VCM
exposure also include mutagenicity. Mutagenesis and carcinogenesis
are sufficiently correlated that demonstration of one is cause for
concern about the other. The carcinogenicity of VCM in humans is
well demonstrated via the NIOSH cohort mortality study and by
various animal studies. There are also data to demonstrate VCM-induced
transplacental carcinogenesis in rats. In the past year, several
reports have indicated that VCM is mutagenic via the microbial test
system, and that VCM metabolities have induced mutations in the
mammalian cells. Likewise, four independent reports from four different
countries have shown an excess of chromosomal aberrations in lymphocytes
of workers exposed to VCM as compared to controls. I should also note
that NIOSH is participating in a collaborative study with a university
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vn • D I!0? lab°r and "anagement of workers exposed to
vinyl chloride in Pottstown, Pennsylvania which should provide
additional information on the mutagenic potential of vinyl chloride
We anticipate that a preliminary report of this study will be
available in the near, future, and we will transmit a copy of this
report to you hopefully before completion of your public hearings and
commentpenod. Thus, while no conclusive data are available
mutaf nesis J" the n""ian setting, such animal and laboratory
suggest a need for caution with respect to human exposures."
Response: EPA appreciates the information submitted by the commentator.
20. VC-9
Comment: The commentator submitted the following five papers dealing
with vinyl chloride.
Pv-^c1;. /Te1]er'.,Ri9hard J" et al-> "Neoplastic Risk Among Workers
Exposed to Vinyl Chloride," Annals New York Academy of Sciences.
MTfKu +n* " et al" "Genetl'c Risks of Vinyl Chloride,"
NIOSH, Post Office Building, Room 515, Cincinnati, Ohio 45202'
January 28, 1976. (Prepublication Copy)
3. Infante, Peter F. , "Oncogenic and Mutagenic Risks in -
Communities with Poly vinyl Chloride Production Facilities."
4. Waxweiler, Richard J. , "Vinyl Chloride: More Than An
'Occupational' Hazard?", APHA, November 1975.
,nH ,»' iES?"d-:i 4r^ D" et al" "Congenital Malformations
and Vinyl Chloride," The Lancet, November 29, 1975, p. 1098.'
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2.2.2. Approach for Regulating Vinyl Chloride Under Section 112.
1. Proceedings of the Public Hearing, Presentation by
Barry Castleman of the Environmental Defense Fund, p.9; VC-23,
VC-10, VC-2, VC-7, VC-16.
Comment: The standard should be based on a cost/risk analysis rather
than best available control technology. In other words, a socially
acceptable risk should be determined. The socially acceptable risk
should be justified by the social importance, that is, the benefits
to society of the article, whose production entails the risk. EPA
did not seriously evaluate the desirability of continuing all existing
uses of vinyl chloride. The Environmental Defense Fund (EOF) pointed
out several uses of vinyl chloride for which EPA named no substitutes
if polyvinyl chloride were banned. One of these was credit cards.
Credit cards are also one of the fastest growing uses of polyvinyl
chloride.
A 95 percent reduction of vinyl chloride emissions should reduce
risk of adverse health effects, but will not necessarily minimize health
risks. Section 112 requires more protection of public health than the
proposed standard will provide, especially in view of the evidence that
polyvinyl chloride products also cause adverse health effects. An
example is hydrogen chloride fumes from burning polyvinyl chloride
products.
A zero emission limit should be established for vinyl chloride.
Vinyl chloride should be phased out. Vinyl chloride usage should be
banned now for products for which substitutes are available. Substitutes
should be developed for the remaining uses of vinyl chloride, and all
vinyl chloride usage should be banned eventually.
Response: In the preamble to the proposed standard EPA named its
reasons for not setting a zero emission limit for vinyl chloride,
as follows: (1) There are beneficial uses of vinyl chloride products
for which desirable substitutes are not readily available, (2) there
are potentially adverse health and environmental impacts from
substitutes which have not been thoroughly studied, (3) there are a
number of employees, particularly in the fabrication industries,
who would become at least temporarily unemployed, and (4) control
technology is available which is capable of substantially reducing
emissions of vinyl chloride into the atmosphere.
EPA agrees that substitutes do exist or could be manufactured
for most vinyl chloride or polyvinyl chloride uses. However, in
general, these substitutes do not have some of the more desirable
characteristics of polyvinyl chloride, such as nonflammibility.
If vinyl chloride and polyvinyl chloride were banned, other substitutes
with these more desirable characteristics would likely be developed.
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EPA presently has no direct control over which substitutes are developed
or used. There is a risk that these substitutes would also have
adverse health or environmental effects. Since control measures
are available which can reduce emissions by 90 percent or more, it
does not seem prudent to reduce emissions by the remaining 10 percent
and take the risk of introducing new untested chemicals into the
environment.
2. VC-3, VC-4, VC-5, VC-8, VC-41
Comments: These commentators favor the approach and standard
adopted for vinyl chloride.
Response: No response is required.
3. VC-17
Comment: There are no readily available substitutes for polyvinyl
chloride products. Any imposed substitution of other materials
for polyvi-nyl chloride products without consideration of the
possible adverse consequences that may result, may have a dramatic
impact on our way of life, including the curtailment of new developments
in such areas as medicine, communication, automotive manufacturing,
aircraft and building industries and fire retardation and safety
equipment. The substitution for polyvinyl chloride products may
have a greater adverse and detrimental effect on both the environment
and the general public's health than the present polyvinyl chloride
products.
Response: This appears to be a response to the comments made by the
Environmental Defense Fund at the public hearing. No response is
required by EPA.
4. VC-46
Comment: Reference is made that the immediate original impact
of a ban would be felt primarily in areas of Southwest Texas and
Southern Louisiana where fourteen of the seventeen plants are located.
Commentator VC-46 believes this statement should be qualified since it
is entirely possible that communities within these areas could conceivably
be in the total state of unemployment if such a ban were to be enforced.
Response: The fourteen of seventeen plants referred to are
ethylene dichloride-vinyl chloride 'plants, and these plants are
located mainly in Southwest Texas and Southern Louisiana. These
plants are typically located in large petrochemical complexes.
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It is very doubtful that a ban on vinyl chloride would cause the
cities of New Orleans, La.; Houston, Tx.; Baton Rouge, La.; and
Long Beach, Calif, to be in a total state of unemployment. Polyvinyl
chloride and fabrication plants are more widely dispersed throughout the
country.
5. VC-16
More
Comment: The vinyl chloride standard is not stringent enough.
stringent restrictions could include (1) no variances on time
schedules to install the best available controls, (2) zero emission
limits for substitutable uses of polyvinyl chloride plastics after
one year, and (3) zero emissions for all sources of vinyl chloride after
three years.
Responses: A response to suggestions 2 and 3 can be found under
comment #1 in section 2.2.2. In regard to the first suggestion, the
Clean Air Act allows for a waiver period of up to two years after the
standard is promulgated to comply with the standard, provided that EPA
"finds that such period is necessary for the installation of controls
11. Variances will not be granted unnecessarily. In many cases it
takes much longer to install control equipment than the 90 days that the
Clean Air Act allows for compliance. Waivers will be granted only for
the time that is necessary to install controls. The standard requires
control of several emission points. It is probable that control
equipment can be installed on some points sooner than others. Compliance
for each different point will be required as expeditiously as practicable.
6. VC-29, VC-31, VC-32,
Comment: Industry suggests that EPA expend more effort on the
fine tuning of the cost/benefit ratio. There are several
requirements in the proposed standard which offer little benefit
in terms of emission reduction for the costs required. They are:
requiring replacement of single seals on rotating equipment with
double seals; installation of car unloading purge units at
plants where monomer delivery by rail car is infrequent; the
requirement for stripping all dispersion resins to 2000 ppm;
excessive recordkeeping, and a gasholder.
The risk of vinyl chloride exposure appears to be entirely
limited to workers in polyvinyl chloride plants. There is no basis
for the prohibition of vinyl chloride and polyvinyl chloride, as some
demand, or for a standard which requires expenditures bearing no
reasonable relationship to the benefits obtained.
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Response: Section 111 of the Clean Air Act provides for the
development of standards based on best control technology
^TLTh5]- -Ve" fder SeCt1°n 1]1' however' "^ndards are not
on a fine balancing of costs versus benefits. Instead costs arp
°f ^ affo^ability of the controTtecto ogf "
POSS be and * Z™" J11"101? 1evel and the economic impact of
possible standards on the industry in question. Unlike section' 111
ifloSld clar? "ot.exP11cit^ Provide for consideration of cSsi 'so
unde? sect on H2 th^aPPr?ST^ t0 C°nsider costs to a 9™ter extent
unaer section 112 than would be done under section 111 As discusspd
in the preamble to the proposed standard for vinyl ch oride EPA believes
costs may be considered under section 112, but only to a very iVmi ted
extent; i.e., to assure that the costs of control technology are not
grossly disproportionate to the amount of control achieved Requirinq a
"6 t0 S0!^1 ^atively small emissions ?rdme
•<- appeared to be a cost which would be grossly dispro-
The 'tems ment1oned by the commentators do not fit in
f ?9
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in its determination of whether controls are needed, particularly
in the absence of any conclusive medical evidence that vinyl
chloride emissions have a detrimental effect on the general public
living in the neighborhood of such plants.
Response: EPA realizes that the costs to install and operate
control systems are generally nonproductive. This is the reason
EPA does an economic impact study. Installation of controls does
have some positive impact on costs to the plant in that more vinyl
chloride is recovered. This is also considered in EPA's economic
s tudy.
9. VC-46
Comment: Three alternatives are proposed in the report. One
alternative would accomplish a 90 percent emission reduction in the
entire plant; another 94 percent; and another 97 percent. The
reason for selecting the 94 percent emission level is unclear,
and this selection should be carefully and thoroughly explained
since the reduction difference between the three options is only
7 percent and the difference between the lower and middle option is
only 4 percent.
Response: It is assumed that the commentator is discussing the
alternatives for the oxychlorination process in ethylene dichloride-
vinyl chloride plants,, The reasons for the selection of these three
alternatives is explained thoroughly in Chapter 5 of the SSEIS, Vol. I.
The reason that the relative degree of difference between the reduction
levels for the three alternatives is relatively small is that the
oxychlorination process is only one of several emission points in an
ethylene dichloride-vinyl chloride plant and on the average it represents
only 10 percent of the emissions from the plant. The alternatives
actually represent a range in emission reduction for the oxychlorination
process from 0 to 99 percent.
The reason that the 94 percent level was selected is explained
in detail in section 8.2.1 of Chapter 8 of the SSEIS, Vol. I. In
summary, the 97 percent reduction level was not selected because of the
large energy expenditure required. The 94 percent reduction level would
achieve some degree of emission reduction without incurring the large
energy expenditure.
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10. VC-26
Comment: IF OSHA allows 1 ppm (8-hour average) as safe to the
health of workers then likewise an ambient air concentration should
be considered rather than an emission standard.
Response: The level of the OSHA standard is not derived from a health
data base. Response to comment VC-32 (page 16) states why EPA did not
choose the ambient standard approach.
11. VC-18
Comment: A standard for ambient concentrations of vinyl chloride can
be based on OSHA's standard. The OSHA action level is 0.5 ppm for
8 hours a day, 5 days a week exposure. An equivalent safe maximum
24-hour environmental exposure would be 119 ppb (8 hr * 24 hr x 5 days
* 7 days X 500 ppb).
Response. Same as for 10.
12. VC-46
Comment: The statement is made that "Congress never discussed the
particular problems associated with apparent non-threshold pollutants."
If Congress did not discuss these problems, it is difficult to justify
EPA's attempt to regulate substances which they consider non-threshold
pollutants without more justification than is presented in this section,
Response: Congress clearly intended for EPA to regulate substances
which "in the judgment of the Administrator may cause, or contribute
to an increase in serious irreversible, or incapacitating reversible,
illness." EPA has determined that vinyl chloride is such a substance
for the reasons stated in response to comment #6 in section 2.2.1. The
fact that sufficient data are not available to delineate a threshold
level of effects for vinyl chloride does not mean that it should not be
regulated.
13. VC-46
Comment: EPA should clarify whether worst case effects were
assumed in establishing the proposed standard.
Response: The proposed standard is based on best available control
technology and is intended to minimize emissions and risk. The
meaning of the comment is not clear. Worst case effects has no
apparent relationship to the basis of the standard.
14. VC-46
Comment: In the preamble to the proposed standard and on pages 8-38
and 8-39 of the SSEIS, Vol. I,there is discussion about the reasons for
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stating the emission levels for sources following the stripper in two
different ways. This discussion seems to infer that the regulation is
proposed for the sake of regulation and enforcement rather than for
accomplishing safety in the surrounding communities.
Response: The goal of the standard which is, as suggested, "the
safety in the surrounding communities" is achieved through the
amount of emission reduction required. Both ways in which the standard
for sources following the stripper is written achieve essentially
the same degree of emission reduction.
15. VC-32
Comment: The proposed standard is unnecessary to provide an ample
margin of safety to protect the public health because the margin of
safety which EPA has implicitly accepted as ample has already been
achieved by industry as a result of the OSHA standard for vinyl chloride
and industry's increasing awareness and understanding of the health
hazard of high level exposure to vinyl chloride.
Response: EPA is aware that emissions have been reduced as a result of
the OSHA standard and industry's awareness of the vinyl chloride problem.
EPA's standard will further reduce emissions. Since the threshold level
of effects for vinyl chloride is unknown, EPA has determined that it is
prudent to minimize emissions by requiring this additional control.
16. Proceedings of Public Hearing, Presentation at the
Public Hearing by Barry Castleman, p.16.
Comment: EPA should have declared vinyl chloride as a hazardous .
air pollutant in June 1974. That way the final standards would have
been due by June 1975. The public would have been spared an
additional year of unregulated emissions. EPA compiled a best
available technology standard after observing the industry through 1974.
Through almost all of 1975, the standard was reviewed by industry,
the public and other government agencies. It is important to try
to put regulations out and shorten this review process.
Response: EPA also favors expeditious rulemaking. However, for
the vinyl chloride standard there were many-technical details and
issues that needed to be resolved before the standard could be
proposed. Preparation of environmental and economic impact statements
for the standard is time-consuming but has beneficial effects in
decision-making and in understanding the impact a standard will have.
EPA's policy of having a recommended standard reviewed by other
groups within EPA, other federal agencies, interested parties, and
public .advisory committees before it is proposed or promulgated is
also beneficial to the quality of the standard.
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17. VC-42
Comment: EPA should provide for a continuous ambient monitoring
program for vinyl chloride in those cases where densely populated
areas are located within five miles from affected plants. Although
ambient standards for vinyl chloride have not been set, historical
ambient data for this air contaminant should be collected because
of strong implications that it is a human chemical carcinogen.
Without ambient monitoring the efficacy of emission controls will not
be known if and when carcinogenicity is confirmed at low ambient
levels.
Responses: Ambient monitoring after the standard goes into effect
would be useful for the reasons suggested by the commentator. EPA
may establish such an ambient monitoring program as resources and
other priorities permit.
18. VC-24
Comment: The following section should be added to the standard:
"The Administrator may waive application of the foreqoinq
regulations (Sections 61.62 -61.65, Sections 61.67 - 61.70) when
the owner or operator of a vinyl chloride plant or polyvinyl chloride
piant_demonstrates to the Administrator that emissions of vinyl
chloride from the plant undergo dispersion sufficient to provide
adequate dilution of the concentration of vinyl chloride insuring
an ample margin of safety. In making this determination the
Administrator may consider:
(1) ambient monitoring data
(2) the location of persons living around the plant site
(3) other relevant information"
Response: EPA has stated that sufficient data is not available
to establish a threshold level of effects for vinyl chloride.
For this reason, EPA has not been able to identify a numerical
ambient concentration which would provide an ample margin of safety.
Furthermore, Section 112 provides for the establishment of emission
standards. It does not provide for establishment of an ambient air
quality standard which can be met by dilution.
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19. VC-22
Comment: In the second paragraph of page 1-6, it is noted that
the standard would be applicable to an existing process, as well as
"any other process developed in the future." This statement is far-
reaching and conjectural. It is not clear how EPA could realistically
regulate specific emission limitations on a future process yet even
to be developed, particularly when the basis for the current limitations
stems from the application of the best available control technology
currently existing.
Response: The statement on page 1-6 refers to the fact that EPA
does not want to limit the standard to existing polymerization
processes by name, because a new variation on the polymerization
process could be developed and not be covered by the standard only
because it was not specifically named. The control technology
required for the existing polymerization process is essentially
the same and is likely to apply to new types of polymerization.
Existing processes vary depending on whether water is used, how
much detergent is used, etc. The equipment used in the various
processes is similar.
20. VC-23
Comment: EPA should make a formal commitment to conduct a complete
review of the standard one year after promulgation. EPA should
keep pushing for improved technology to reach the ultimate goal
of zero emissions. EPA should review all new construction to see
that best control technology available at the time is installed.
Response: It is EPA's policy to review the need to change standards
as new technology is developed. Priorities would determine when a
standard is revised. Priorities are determined by 'the amount of
impact a new standard or revised standard for a particular pollutant
would have in comparison to setting or revising standards for
another pollutant.
21. VC-42
Comment: EPA should push the development of improved stripping
technology by setting a two-phase standard. The first phase would
require stripping to 400 ppm as proposed. The second phase would have
a plant-wide fixed-point emission standard of 100 kg vinyl chloride
per million kg of polyvinyl chloride in any product, averaged over
any calendar day. The second phase standard could be achieved in
5 years.
Response: EPA also favors development of improved stripping technology.
Section 112 of the Clean Air Act doesn't directly provide for a two-
phase standard. It states that a plant must meet a standard
2-25
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within 90 days of promulgation, unless a waiver of compliance
is obtained. If a waiver is obtained, the plant must meet the
standard within two years of promulgation. EPA can revise the
standard at a later date.
EPA's requirement for stripping to 400 ppm does not preclude
the States from setting more stringent standards. Technology is
being developed which can reduce the stripping levels below 400 ppm
for many resins. States may decide to require plants, particularly
new plants, to adopt this new technology and reduce emissions even
more. The 400 ppm limit should not be considered an end-point in
the development of improved stripping technology.
The basis of the 100 kg vinyl chloride per million kg product
is unclear. The controls which would be used to attain this
level were not described in the comment.
22. VC-24
Comment: The technology necessary to achieve compliance with the
proposed regulation is untried. There are some indications that
compliance with the regulations may create other equally troublesome
problems. As an example, recovered vinyl chloride monomer has been
found to contain certain polyperoxides which are percussion
sensitive thereby creating an explosion hazard. If these by-products
of emission control create significant health hazards, the regulations
should provide a mechanism whereby the Administrator can modify
the regulations on an emergency basis.
Response: All the technology required by the standard has been
used. The industry has been recovering vinyl chloride in the past for
economic reasons and that a problem with polyperoxides exists has
not been mentioned previously.
23. VC-44
Comment: The standard should include a specification for plume dispersion
hardware to preclude the possibility that the dryer stream may be
discharged at near ground level. The concentration of vinyl chloride
in the dryer exhaust may well exceed 10 ppm and be carried at this
level for some distance'if no stack is used. In fact, air flow
calculations for a polyvinyl chloride dispersion plant in Maryland
indicate that there would be a possible maximum ambient concentration
in excess of 1.0 ppm across the property line after the plant has
met the provisions of the proposed regulations.
2-26
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Response: In order to require plume dispersion hardware, since
a number of plants would be involved, EPA would have to specify
an ambient air quality goal for vinyl chloride. EPA has not
done this because there is not sufficient data on health effects
to establish a numerical threshold of effects for vinyl chloride.
In visiting polyvinyl chloride plants, EPA has observed that
dryer stacks are generally 15 meters high and discharge horizontally.
Concentration levels of 1. ppm are of concern. States may find
that they want to require dispersion hardware to further reduce ambient
concentrations. The fact that EPA has not required dispersion hardware
does not preclude States from doing so, nor should it discourage them
from doing so.
24. VC-42
Comment: The standard should include a limit on the mass emissions
allowed per unit time. Otherwise, the total emissions will simply
grow as plant size increases.
Response: There are advantages to a mass per unit time standard. It
could be used to limit growth as suggested. It would also clearly
preclude dilution as a means of attaining the standard.
EPA, however, did not propose a mass emission limit for two
reasons:
(1) The standard is based on best available control technology
rather than an ambient air quality goal. If the ambient air quality
goal approach had been used, EPA would have calculated an emission
rate for the entire plant which would allow the plant to meet the
ambient air quality goal under worst case conditions. The emission
rate in kg/hr would have been adopted as the standard.
(2) The air volumes and mass emissions from specific emission
points, particularly at polyvinyl chloride plants, fluctuate. There
are a number of pieces of equipment at each plant. The configuration
for ducting the emissions from the different pieces of equipment varies
from plant to plant. Reactors and strippers at most plants are batch
processes. Capture and ducting of fugitive emissions to a control
device is intermittent. Sufficient information is not available
for developing a mass emission standard which could be applied
to all plants.
2-27
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2.3. Selection of Source Categories
2.3.1 §61.60
Comment: Research and development facilities should be exempted from
regulation. Research, testing, and pilot plants are important tools
in developing new products, improving productivity, devising new
procedures to achieve lower emissions, and enhancing safety. Such work
involves reactions of vinyl chloride in small glass vessels, miniature
reactors set up on a laboratory bench and/or small reactors. These
facilities are operated on a "need to investigate" basis and therefore
operate intermittently. To require that each reaction or other
experiment be fully equipped with the various required control devices
to meet a 10 ppm maximum concentration would be extremely burdensome
as well as delay needed work to advance emission and safety control
technology.
Many experimental equipment set-ups are not permanent installations.
in fact, a particular set-up may involve only one experiment. To
comply with the proposed standard, the operator would have to conduct
emission tests, prepare an initial operating report and a semi-annual
report, and maintain records of emissions for two years.
_In addition to testing and reporting, the requirements in the
section on fugitive emissions become quite cumbersome in pilot operations
The sample flask system on a small reactor becomes almost as large as
the reactor itself. Pilot size pumps are simply not available with
double mechanical seals. Finally, a formal leak detection and
elimination procedure would be burdensome, and stripping of waste
water to 10 ppm vinyl chloride concentration seems excessive in
this case.
The current data in Table I, collected from 14 members of
SPI representing 75 percent of the nameplate poly vinyl chloride capacity
in the United States illustrates that estimated emissions from 113 test
sources account for less than 0.06 percent of the total monomer emissions
from all sources before control and 1.0 percent after all model plant
controls are in use.
The vessels used for these experiments range from under 3.78 1
(1 gal) to 4158 1 (1100 gal). The ninety vessels of 189 1 (50 gal)
and below represent more than 50 percent of these emission sources
Commentator VC-29 recommends that vessels 1890 1 (500 gal) and under
be exempt from all emission standards because of the aforementioned
data and because OSHA guidelines adequately protect the workers. Vessels
over 1890 1 (500 gal) should be required to limit emissions to 5 kg
(5 Ib) vinyl chloride monomer per 100 kg (100 Ib) of polyvinyl chloride
produced.
2-28
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Table I. EMISSION DATA ON LABORATORY AND PILOT FACILITIES USING VINVL CHLORIDE
Estimated
Company Reactor Number Produced Total Emissions
Code Size of Units Rate per Year Resin Use
A
B
C
D
K
L
H
N
(gal.)
50
0.4
3.25
300
50
0.5
0.8
0.8
15
30
30
1100
300
5
10
.5
10
50
.5 to 2
50 to 100
750
200
15
10
50
200
220
500
1,000
5
30
300
2.5
10
12.5
200
30
10
30
0.5
1
10
100
500
600
2
6
1
1.
1
I
4
2
6
1
2
2
3
1
1
2
2
11
5
2
1
1
1
7
1
*-
1
4
1
1
1
1
4
i
2
2
1
7
2
1-
1
1
(Ib/yr)
30,000
. 1,084
987
36,450
17,000
192-
2,112
600
23,100
960
28,800
666,000
113,812
400-
100~
380-
27,338
136,687
16,000
10,000
50,000
72,900
5,468-
608-
75,634
2,430-
12,029
7,594-
33,413
76
5,285
31,894
1,823
606
15,480
24,000
34,172
66,582
24,698
1,200
1,063
304
6,075
1,519
364,500
400
89
100
5,000
2,800
48
697
878
240
240
266
10,656
10,000
6,075
3,038
25
1,600
10,800'
225
500
2,000
17,045.
928
100
4,870
192
3,110
60
460
8
321
2,582
100
30
1,548
2,400
375
21,920
2,740
1,700
350
50
1,000
100
4,000
Testing and scrap
Experimental
Experimental
Tests, trials in
lab and to
customers
Sold as off grade
Scrap
Scrap
, Scrap
Scrap
Scrap
Scrap
Scrap
Divided between:
1. Experimental
evaluation & tests
2. Customer samples
3. Remainder is
placed in landfill
(about 80%)
Experimental
Experimental
" "Experimental
Scrap
Scrap
Customer Sampling
and scrap
Testing
Testing
Testing
Testing
Testing
Testing
Testing S sampling
Testing & sampling
Testing & scrap
Testing & scraj?
Testing S scrap
Product research
Blending and/or
scrap
Blending and/or
scrap
Testing
Testing
Testing
Testing
Testing
Testing & blending
into normal
production
2-29
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Other cut-off points were suggested by other commentators.
VC-13 wants to exempt all research and pilot plant facilities.
VC-40 wants to exempt reactors with a capacity of 7560 1 (2000 gal)
or less. This would also essentially exempt all research and development
facilities. Commentator VC-27, the operator of an ethylene dichloride-
vinyl chloride plant, requested that quality control facilities be
exempted from the standard.
Response: As stated in the preamble to the proposed standard, EPA
recognizes that some small research and development facilities may
exist where the emissions of vinyl chloride are insignificant and
covering these facilities under the standard would be unnecessary and
inappropriate; however, EPA did not have sufficient information available
to clearly define which facilities should be excluded from the standard.
The standard has been revised so that it exempts polyvinyl chloride
reactors and associated process equipment from applicability of the
standard if the reactors are used^for research and development and have
a capacity of no more than 0.19 m (50 gal). The figure 0.19 (50 gal)
was selected because it distinguishes between research and development
equipment that is generally found in the laboratory and that which is
found in pilot scale facilities. The emissions from the laboratory
scale facilities are relatively small and application of the controls
required by the standard would be impractical and expensive. ^Reactors
greater than 0.19 m (50 gal) in size but no more than 4.07 m (1100 gal)
are required to meet the 10 ppm emission limits for reactors, strippers,
monomer recovery systems, and mixing, weighing, and holding containers.
Research and development equipment in this size range would encounter
technical problems in meeting other parts of the standard. For most
resins meeting the reactor opening emission limit involves reducing
the number of reactor openings. In research and development the reactors
have to be opened after every batch for thorough cleaning. With regard
to the stripping requirements, one of the purposes of research and
development is to gain an understanding of the conditions.which need to
be carried out during the stripping operation for a particular resin to
meet the standard. The first part of the research involves development
of a marketable product. A later phase involves development of the
stripping conditions for the resin. Each batch in a research and
development reactor could not be expected to meet the stripping limitations,
Averaging would not help because typically only one or two batches are
made daily.
o
The figure 4.07 m (1100 gal) was selected as an upper cut-off
limit because there are no commercial reactors below this size.
An exemption for research and development equipment in ethylene
dichloride-vinyl chloride plants is not needed. Most research at
these plants involves the oxychlorination process. Requiring pilot
scale oxychlorination processes to meet the stack standard is consistent
with requiring research and development equipment in polyvinyl
chloride plants to meet the 10 ppm limits. The fugitive emission
limits apply only to equipment "in vinyl chloride service."
2-30
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Since the equipment in the oxychlorination process is not "in vinyl
chloride service," the fugitive emission requirements would not
apply to the research and development equipment.
Quality control facilities dp not need to be exempted, because
they are not covered by the standard. Equipment which is not specifically
named by the standard (e.g., reactors, strippers, oxychlorination
process, etc.) would not have to be controlled.
2. VC-25
Comment: Copolymer resin plants manufacturing resins with less than
a 50 percent vinyl chloride content should be regulated as any other
polyvinyl chloride resin plant is regulated. EPA should, however, clarify
the application of the proposed standard to operations involving
vinyl chloride use on an intermittent basis. On any given day, our
plant may manufacture copolymers containing vinyl chloride or it may
be manufacturing an unrelated material. Vinyl chloride monomer will be
stored on the premises permanently though use is intermittent. EPA
should not require records, tests, and reports for the whole operation
of the plant, except when vinyl chloride is being used. Each production
run of a latex containing vinyl chloride should not be counted as a
new source and a reactor line should not have to be requalified via
emission tests and an initial report each time a production run is made.
2-31
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Response: On days when vinyl chloride is being stored and not used,
the only part of the regulation which would appear to apply would be
the Requirement for detection and elimination of leaks from the storage
equipment. Any reports and records would simply indicate which days
vinyl chloride was or was not being used. The plant would not be
considered a new source each time it started producing a vinyl chloride-
containing product.
3. VC-25
Comment: Solution resins should be exempted from the standard, because
emissions from manufacturing solution resins compose only 0.028 percent
of the total, EPA doesn't understand the solution process, and the
proposed standard does not adequately consider solution polymerization
technology.
Response: There is only one plant making solution resins This
explains, at least in part, why the emissions are relatively low
and why EPA did not concentrate more time on this process. The
fact that only one plant makes solution resins is not a reason for
exempting the plant from regulation. The number of plants in other
parts of.the country is irrelevant to the effects of the solution
resin plant in the community surrounding it. The information presented
the standard indicated that this plant is capable of Meeting
2-32
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2.4 Emission Limits
2.4.1 §61.62(a), 61.63(a), and 61.64(a)(l),(b),(c), and (d).
1. VC-14, VC-18, VC-21S VC-22, VC-29
Comment: It has not been demonstrated that incineration, carbon
adsorption, and solvent absorption can achieve the proposed emission
limit of 10 ppm under different production conditions at all sources.
It is arbitrary for EPA to base a standard on the operation of
experimental or infrequently used control devices required by the
standard to operate at their best efficiency 100 percent of the time.
Some thought should be given to alternate actions in case these devices
prove unworkable.
Commentator VC-18 also stated that carbon adsorption is not
attractive for vinyl chloride plants because impurities in the
recovered vinyl chloride prevent putting it back into the production
line. Commentator VC-18 also pointed out that the results from the
test EPA conducted on an incinerator showed higher emissions from
the HC1 scrubber following the incinerator than from the incinerator
itself. He recommended changing the standard to 50 ppm now and
revising it later to reflect best available control technology as it
is verified and demonstrated.
Response: EPA has acknowledged that relatively .little data exists
on the emission levels achievable for carbon adsorption, solvent
absorption, and incineration at ethylene dichloride-vinyl chloride
and polyvinyl chloride plants. During the development of the proposed
standard, these control techniques were being used by only a few plants,
so little .testing was done. EPA did test one incinerator. The outlet
concentration averaged over six runs was 4 ppm. Thus, the proposed
standard is set higher than the average measured concentration to allow
for a variation in conditions among plants. Furthermore, EPA feels
that the 10 ppm limit has been demonstrated from incinerators on
similar streams to those in ethylene dichloride-vinyl chloride and
polyvinyl chloride plants.
Furthermore, conditions of the stream that is to be treated at a
particular plant are taken into account in designing a control device
to meet the standard. The standard accounts for normal fluctuations in
emissions by permitting averaging of emissions. Compliance with the
10 ppm limit is to be determined by averaging together the results
of these runs. Each run consists of sampling for a minimum of an
hour.
If carbon adsorption is not a feasible control technique for a
vinyl chloride plant, incineration is a viable option. There is no
apparent reason to increase the 10 ppm limit to 50 ppm based on the
data that are available.
2-33
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EPA does not know why the vinyl chloride concentration from the
HCL scrubber outlet was higher than the concentration going into
the scrubber. The water used in the scrubber was from a wastewater
sump, so there is a possibility that it did contain vinyl chloride.
Water samples were taken from the scrubber and were reported to
contain no vinyl chloride. However, the water samples may have
been taken improperly. At the time of this test, EPA had not specified
a method for measuring vinyl ch-loride in water. If the container used
to obtain the sample was not completely filled with water, then vinyl
chloride in the water could.have escaped into the air space in the
container above the water so that it was not measured. The test discrepancy
does not detract from the figure of less than 10 ppm for the exit stream
from the incinerator.
2. VC-14
Comment: Sections 61.62(a) and 61.63(a) prohibit the discharge of
exhaust gases which contain 10 ppm vinyl chloride or greater from
"any equipment." As worded, these sections apply to fugitive emission
sources as well as stack emissions. These sections should be amended
to limit their applicability to stacks and vents used specifically
for purposes of discharging vinyl chloride-containing gases from the
process equipment.
Response: The fact that Test Method 106 is to be used to determine
compliance with §§61.62(a) and 61.63(a) and that Test Method 106
is a stack testing method with a minimum sampling time of an hour
indirectly excludes fugitive emissions such as leaks from valve stem
packing and flange gaskets from applicability of the 10 ppm standard.
Adding a statement to the effect that only "stacks and vents used
specifically for purposes of discharging vinyl chloride-containing
gases" could result in additional uncertain!'ties. For example, the
specific purpose of a stack may be to vent ethylene dichloride, but
vinyl chloride may also be a pollutant in the gas stream. Or the
primary purpose of a vent may be to remove heat.
3. VC-26
Comment: The 10 ppm maximum vinyl chloride emission limits for the
low volume ethylene dichloride purification and vinyl chloride formation
and purification stacks are not realistic. To get down to 10 ppm
would require at a minimum the use of carbon adsorption. Since EPA
uses a cost benefit ratio to justify the 0.02 lbs/100 Ibs of product
for the oxychlorination process, it seems more realistic to apply this
same weight standard to all of the.stacks.
Response: The primary reason for making the standard for the oxy-
chlorination process less stringent than for the other emission points
is the large energy expenditure that would be required at many plants
to reduce the oxychlorination process emissions to 10 ppm. Little, if
any fuel, is required for incineration of emissions from the ethylene
dichloride purification and vinyl chloride formation and purification
processes. Furthermore, the uncontrolled emissions from these two
2-34
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processes are a much larger percentage of the total emissions from an
average plant than those from the oxychl or i nation process^ The incinerator
tested by EPA is controlling the ethylene dichloride PuriflcjJ10
vinyl chloride formation and ourification process and meets the 1
limit.
4. VC-18
Comment: During formation of vinyl chloride, there is a column to
separate by-product HC1 from the vinyl chloride. The HC1 overhead
in this column is ducted to the oxychl ori nation process. During
upsets of this system, HC1 must be vented to the atmosphere This
stream contains about 30 ppm of vinyl chloride. _ We es t™ate th ^
venting occurs about five times per year releasing 12. Ib kg U/ IDS;
of vinyl chloride oer year. Removing this small amount of vinyl chloride
will increase the cost of our control device $500,000. This stream
should be exempted from §61.63(a).
Response: EPA has discussed this problem with two ,huere
Both of these comoanies avoid venting the HC1 stream to the atmosphere
by operating the cracking furnaces only when the oxychlorination process
is operating.
5. VC-35
Comment: The 10 ppm limit for vinyl chloride emissions from the _
various control equipment should specifically mention that it is to be
determined prior to mixing with other gases.
Response: On October 14, 1975 (40 FR 48299) §61.17 was added to
Subpart A - General Provisions of Part 61. Section 61.17 (entitled
"Circumvention") prevents an owner or operator from building, erecting,
installing, or using any article, machine, equipment, Process, or
method, the use of which conceals an emission which would otherwise
constitute a violation of an applicable standard. Dilution would
be a method of concealing an emission which would otherwise constitute
a violation of an applicable standard.
6. VC-18, VC-21, VC-25, VC-29, VC-34
Comment: An averaging time of 30 days should be provided for the
10 ppm limit for stack emissions. Otherwise multiple back-up systems
will have to be employed at a grossly disproportionate cost in order
to meet the 10 ppm limit on an instantaneous basis.
Response- The standard does provide for an averaging time of at
least three hours. Section 61.67 states that an emission test is
to consist of three runs. Each run is to be an hour in length.
The continuous monitor provides an indication of instantaneous
emissions, but will not be used to determine compliance.
2-35
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2.4.2 §61.62(b)
1. VC-23
Comment: EPA proposed a less stringent standard than can be met
by incineration for the oxychlorination reactor because of the
large fuel penalty that would be incurred to incinerate the
emissions from that source. Afterburners designed especially for
these plants can attain substantial heat recovery, and catalytic
afterburners offer energy savings by being able to operate at lower
temperatures than conventional units. The use of afterburners (and
scrubbers) to control emissions from oxychlorination reactors should
be required. The price of fuel will be sufficient incentive for
plants to install well-designed systems.
Response: EPA recognizes that two plants are using afterburners
for control of the oxychlorination reactor. In both cases, the
plants are reducing the large volume gas stream and thus the high
energy costs by recycling the process gas stream and using oxygen
instead of air to feed into the process. Although the cost of fuel
does provide incentive to install this kind of system, there are
several types of oxychlorination reactors and EPA does not know
whether this system could be adapted to all the reactor types within
the time available for compliance. A catalytic oxidation unit has
been used in a pilot study for the oxychlorination process, but it
has not been used commercially. It should be emphasized that energy
is only one factor in EPA's decision. At most plants the
oxychlorination reactor is a relatively small portion of the total
emissions. At the one plant where the oxychlorination reactor has
relatively significant emissions, the incineration may have to be
used if a change in process variables will not result in the plant
meeting the standard.
2. VC-28
Comment: To meet the 0.02 kg/100 kg limit, more than a change in
process variables will be required. The standard should be set
slightly higher to avoid the use of incinerators or an additional
reactor in the oxychlorination process.
Response: The additional reactor in the oxychlorination process,
which is being used by several plants, does not require a large
expenditure of energy as 'does an incinerator. If the additional
reactor is required to meet the .02 kg/100 kg requirement, there is no
apparent reason why it should not be used.
2-36
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3. VC-27
Comment: The preamble to the proposed standard states that "... as
technologies using less energy for controlling the oxychlori nation reactor
are developed, EPA will evaluate the desirability of proposing standards
which would require a higher degree of control at all plants." The
possibility of more stringent regulation as technologies might develop
forces serious evaluation of the prudence of current prompt investment
and emission control efforts which might be rendered obsolete in
the future, without due consideration of ambient air emission levels
then existent and further assessment of the results of substantial
efforts now underway to quantify health risks at very low exposure
levels. ,
Response: It is EPA's responsibility to examine new technology
as it is developed and revise its standards accordingly. If EPA
developed a more stringent standard for the oxychlorination reactor,
it would also look at the impact of adopting that standard for
existing plants. Depending on these impacts, EPA may apply the
standard only to new plants by developing the standard under
section 111 of the Act.
2.4.3 §61.64(a)(2)
1. VC-29, VC-22
Comment: The inclusion of the words "is open and" in the last
sentence of §61.64(b), (c), and (d) is inconsistent with the wording
"before opening" in §61.65 (b)(6)(i) to which this sentence applies.
For clarity and to resolve this discrepancy, the last sentence of
§61.64(b) should be reworded as follows: "This requrement does not
apply to equipment that meets the requirement in §61.65(b)(6)(i)."
Response: The commentator's suggestion does not appear to clarify
the sentence. This is exemplified by inserting his suggestion in the
last sentences of §§61.64(b), (c), and (d). They would then essentially
read as follows: "The 10 ppm requirement does not apply to equipment
that before it is opened the quantity of vinyl chloride is to be reduced
so that the equipment contains no more than 2.0 percent by volume vinyl
chloride ... etc." The intent of the last sentence of §61.64(b), (c),
and (d) is to say that the 10 ppm requirement does not apply to equipment
that^ i^ open and has already met the requirement in §61.65(b)(6)(i)
before it was opened. In other words, the standard does not apply to
equipment which is not in operation. In the promulgated standard, the
last sentence in the proposal §61.64(b) has been changed to: "This
requirement does not apply to equipment that is open and out of operation
and that met the requirement in §61.65(b)(6)(i) before it was opened."
2-37
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2. VC-13, VC-21, VC-25, VC-29, VC-33, VC-34
Comment: The reactor opening emission limitation should be changed to
permit averaging all reactor openings over a 30-day period. In the case
of the reactor opening limitation, the requirement that each reactor
opening must meet the limitation is burdensome and, in addition, may
cause hazardous situations. EPA has discussed in the SSEIS, Vol I
on page 4-71 its logic in developing the standard. It requires that
?YU?.an av^age Of 3'5 batches before opening and cleaning.
Ruling and/or the need for cleaning varies from one resin
a"othe.r' Traditionally, on the completion of each batch, the
op ato*;.has made a judgment based on inspection, heat transfer,
K £°"dltl°u °r history as to whether the reactor should make
5 ? °^ whether u sh°uld be cleaned. Failure to clean at the
+h - ° ^h1gh Percentage of runaway reactions and emergency
air' C1*amn9 to° °ften ^ costly and results in higher
5^ standard requires multiple batches between each
; thus, a plant operator with a reactor that fouls
. • must choose between violating the standard or operating
a reactor in an unsafe manner.
«n» f°r reactor opening has not been increased
9a? stand?rd- In ^e SSEIS, Vol. I several ways of
rCt°r pem"g em1ssio" limit were mentioned. One of these
1s t0 evacuate the
3. VC-21, VC-22, VC-29
1? ai?/rror 1n calculating the emission factor for
shon!H ™ C512rlde m?nomer in reactor openings. The concentration
deHved C°nVerted to weight percent before the emission factor is
Response: The calculation was provided by a company and should
have been converted to a weight basis. Recalculation gives a
rhwfSi0" S1SSl°n/aSt?r °f °-°°2 kg Vlnyl chloride/100 kg polyvinyl
chloride. The standard has been changed to reflect this correction.
2.4.4 §61.64(e)
1. VC-22, VC-24, VC-28, VC-29
PSSed s*andard requiring that dispersion resins
?°°°-Ppm ""? t00 stn""gent. EPA recognized the
icul^J "s^PPing dispersion resins and the
state of technology relating to stripping of dispersion
2-38
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resins. EPA also recognized in the preamble to the proposed standard
that achievement of the requirements for dispersion resins depends
on development of more advanced control technology in the period
subsequent to the promulgation of the standard and prior to the
effective date of some of its provisions.
Extensive scientific research is presently being conducted
to develop this control technology and these efforts have been
successful for many dispersion resin products. However, after more
than ten months of concentrated research, there still remain several
dispersion resin products which cannot be stripped to 2000 ppm
residual vinyl chloride. Stripping capability for these dispersion
resins range from 3000 to 10,000 ppm residual vinyl chloride. It
now appears uncertain that sufficient time remains to allow development,
engineering, equipment procurement, installation, and demonstration of
the necessary stripping equipment within the maximum compliance time.
Due to these factors, EPA should give additional consideration to
the standard for dispersion resins prior to promulgation of the final
standard.
Specifically, the industry requests the allowable residual
vinyl chloride content of certain dispersion resins to be set at
6,000 ppm. The specific dispersion resins to which this 6,000 ppm
limit should apply shall be based on a manufacturers demonstration
that specific resins cannot be stripped on a commercial scale of
2,000 ppm. The industry pledges its efforts to continue researching
methods of stripping all dispersion resins to a residual
level of 2,000 ppm or less and invites EPA to reevaluate
dispersion resin stripping technology in mid-1978 and to
regulation as appropriate.
vinyl chloride
the status of
amend the
Response: EPA also recognized in the preamble to the proposed standard
that some grades of resins are more difficult to strip than others.
Therefore, rather than requiring that each grade of dispersion resins
be stripped to 2,000 ppm, the proposed standard permits industry to
average different grades of dispersion resins together over a 24-hour
period. Only one of the eight manufacturers of dispersion resins
specifically commented that the dispersion resin standard should
be made less stringent. Only two of several grades of dispersion resins
made by this company cannot meet the 2,000 ppm limit. In considering
this information and the information obtained prior to proposal of the
standard, EPA has decided that making the standard less stringent is not
warranted.
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2. VC-44
Comment: The proposed standard for dispersion resins is not stringent
enough. There appears to be a technical inconsistency in the fact
that the dispersion resins cannot be stripped to less than 2 000
ppm and yet they are easily "stripped" in the dryer with the monomer
discharging into the air. Since the mass transfer of monomer through
the polymer is, undoubtedly, the limiting factor in each case, it
would seem that additional product exposure time in the "stripper"
could produce a concentration lower than 2,000 ppm. The conclusion
drawn by EPA that 2,000 ppm will reflect the best available control
technology in "2 1/2 years" seems pessimistic. If this limit
is set at 2,000 ppm, there will be no incentive to reduce it further. :
Response: The primary difference between the polymerization of
dispersion resins and other resins is the relatively large amounts of
emulsifying agent used in the polymerization of dispersion resins
The emulsifying agent combined with strong agitation prevent
coalescence of the polymer particles. This results in smaller particles
than are obtained by other polymerization processes. High temperatures
cannot be used in the stripping process because this would cause
coalescence of the particles and thus degradation of the final product
Prolonged stripping causes discoloration of the final product.
There is a difference in the conditions between the stripper
and the dryer which affects the transfer of vinyl chloride out of
the resin. In the stripper the resin is surrounded by water which
tends to inhibit the release of the vinyl chloride from the resin
The vinyl chloride would have to move out of the resin into the
water and then into the vapor space above the water. The drying
of dispersion resin takes place in a spray dryer, where the small
resin particles are atomized. Each particle is therefore exposed
to a large surface area in the dryer. The water is evaporated
off the particle. This eases the escape of vinyl chloride from the
particle.
3. VC-20
Comment: It is not clear how the residual amount of vinyl chloride
in the dispersion resin has a significant bearing on stack emissions
from process equipment. It would appear that steps can be taken
without significant additional cost to reduce stack emissions from
process equipment for dispersion resins to the same levels as the other
resins.
EPA should emphasize the importance of special handling required
nn isPf^sion ^sins which have a 2,000 ppm vinyl chloride content.
EPA should also announce a schedule requiring industry to reduce vinyl
chloride levels in dispersion resins.
Response: The emissions from stacks on dryers, silos, and other process
equipment following the stripping operation are due to residual vinyl
2-40
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chloride in the dispersion resin. These emissions can be controlled in
two ways. Either more vinyl chloride can be stripped out of the resin
or control equipment can be placed on the stack. As explained in the
preamble to the proposed standard, dispersion resins are more difficult
to strip than other resins. Also, a different kind of dryer is used in
the manufacture of dispersion resins than is used for other resins.
This dryer uses larger volumes of air than the other dryers. A
control device reducing the effluent to a given concentration therefore
does not reduce the mass emissions from a dryer at a dispersion resin
plant as low as at other resin plants. At dispersion resin plants, add-
on control devices achieve about the same degree of emission reduction
as stripping to 2,000 ppm. So there is no advantage to requiring add-on
controls. The cost of add-on controls at an average dispersion plant
is significantly higher than improved stripping. For improved stripping,
the installed capital cost is $3,319,000 and the total annualized cost
is $1,363,000. For incineration, the installed capital cost is $5,287,000
and the total annualized cost is $4,892,000.
EPA investigated the possibility of reducing the air volume from
dispersion resin dryers by a recirculation system. This does not appear
to be a practical solution.
In regard to special handling for dispersion resins, when the
processing (drying) of dispersion resins is completed, the product
contains no more residual vinyl chloride than other resin types. There
is no provision under section 112 of the Act for setting up a schedule
for reducing vinyl chloride levels in dispersion resins. EPA can,
however, review the status of control at a later time and revise the
standard as appropriate.
4. VC-40
Comment: Allowing averaging of different resin grades is unfair
to a small polyvinyl chloride plant that makes only one resin grade.
The resin made by this company is a copolymer and is more difficult
to strip than homopolymer. Other producers have the flexibility
of being able to average together homopolymers and copolymers.
Response: EPA agrees that the averaging concept does favor the larger
plant making a variety of resin grades. However, EPA contacted another
company which manufactures the same copolymer as the commentator. This
copolymer is essentially the only resin produced at one of its plants. The
company reported wide variations among batches with regard to the degree
of stripping that is achieved. However, over a 24-hour period there are
a large number of batches produced and the average of all batches consistently
meets the 400 ppm limit. Differences in recipes used at different plants,
however, can affect the stripping levels achieved. Considering this
information and the fact that the averaging concept does provide needed
flexibility for the industry as a whole, EPA has not removed the provision
for averaging from the standard.
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5. VC-25
Comment: In the preamble to the proposed standard, EPA stated that
"since stripping technology is currently in the development stage, it is
possible that lower levels of emissions will be achievable before
promulgation of the proposed standard. Interested parties are invited
to submit during the comment period factual data on the status of
stripping technology." Commentator VC-25 believes that EPA should not
lower the 400 ppm proposal for stripping for two reasons:
(1) It would disrupt the industry's on-going plans to comply
with the proposal. It takes time and major new capital investment
to design, purchase, and construct necessary equipment and facilities.
In many cases the two-year statutory limit for waivers is not adequate
to carry out a major change.
(2) There is a lot of variation in the degree to which resins can
be stripped. The company represented by the commentator has directed
its own research organization to seek improvements in its stripping
technology and has actively sought information on various technologies.
While many of these technologies offer some advantages in special areas
and products, there is no universal technology for all plants, products,
and processes. Within the commentator's own processes and plants, he
has observed a variation in stripping of residual vinyl chloride monomer
from 5 ppm to 600 ppm, exclusive of the dispersion resins which meet the
2,000 ppm limit proposed in the standard. The commentator is experiencing
great difficulty in achieving the 400 ppm limit for copolymer resins.
Currently, these are in the 400 ppm to 600 ppm residual vinyl chloride
range.
Response: EPA has decided not to reduce the 400 ppm limit at this
time. It appears that some resins can be stripped to much lower
levels than others. Copolymers appear to be more difficult to strip
than homopolymers. Because of this variation, data on stripping
levels for different products would have to be obtained. Substantial
reduction in the 400 ppm limit would probably require reproposal of
the standard for public comment. This would delay the implementation
of any standard. EPA has decided that revision to the 400 ppm limit,
if any, will take place at a later date after promulgation of the
400 ppm limit. EPA's decision to not reduce the 400 ppm limit in no
way suggests that States are to be discouraged from doing so as newer
technology is developed.
6. VC-42
Comment: The proposed level of 400 ppm may be satisfactory in the
initial control; however, it should be pointed out that information
available in the literature indicates that residual concentrations
considerably below 400 ppm are achievable in some types of polyvinyl
chloride resins. Diamond Shamrock and B. F. Goodrich report
achievable levels which indicate that the figure 400 ppm could be
lowered to 100 ppm or less for some resins.
Response: Same as #5.
2-42
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7. VC-28
Comment: The preamble to the proposed standard suggests that
stripping technology can be developed within two years following
promulgation of the standard. This assumes that a plant can get a
waiver of compliance. There is no guarantee that an existing plant
can obtain a waiver. Also, newly constructed plants cannot obtain
waivers and would have to meet the 2000 ppm limit within 90 days of
start-up. This would deter construction of new plants.
Response: It is true that there is no guarantee that a waiver
would be granted to allow the development of stripping technology
for dispersion resins. However, it is likely that EPA would grant
resin manufacturers the maximum two years to comply with the stripping
part of the standard if they complied with the other provisions of
the standard and reduced the vinyl chloride levels in the resin as
much as possible in the two year period. This was a consideration
in EPA's decision to base the standard on developing technology
rather than on technology available at the time that the standard
was being developed.
With regard to newly constructed plants, it is true that
section 112 does not provide for waivers of compliance. A "new source"
is defined in §61.02 of the General Provisions as a stationary source,
the construction or modification of which is commenced after the
proposal of the standard. The owner or operator constructing a new
source would therefore be aware of the requirements of the standard
before construction is commenced. Whereas the owner or operator
of an existing source would have to retrofit a plant to meet the
standard, it would appear that the owner or operator of a source
undergoing construction can more readily design that source to meet
the standard. It seems appropriate to prohibit newly constructed
sources from operating out of compliance with the standard.
8. VC-13, VC-18, VC-21, VC-29
Comment: The intent of the standard is that once the polyvinyl
chloride resin has been stripped to 400 or 2000 ppm, as appropriate,
all of the emission requirements from that point on in the process
have been met. Two changes in wording should be made to make
the standard consistent with this intention.
First, after the resin has been stripped to 400 ppm or 2000 ppm,
the plant owner or operator should be able to open the stripper with
the resin in it without having to meet the "opening of equipment"
requirement in §61.65(b)(6). The vinyl chloride which escapes
from the resin into the vapor space above the resin should be exempted
from meeting the "opening of equipment" requirement.
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_ Second, the standard now requires that the resin be sampled "as it
is transferred out of the stripper." This phrase should be removed so
5 +S P J uVner °r °Perator can measure the resin in the stripper
and then be able to carry out additional functions in the stripper
without_meeting additional emission requirements before transferrina
the resin out of the stripper.
Response: EPA agrees that the intention of the standard is to limit
n^n^T/tn^Y11 °Perat1°nS followin9 tne stripping operation to 0.04
or 0.2 kg/100 kg product, as appropriate. Therefore, the standard has
been revised so that^samples of the resin are to be taken immediately
Ann61" ^nnn PPing 1S comPleted- If the sample contains no more than
400 or 2000 ppm, as appropriate, operations beyond the stripping opera-
tion are in compliance with the standard even if those operations take
place in the stripper. Also, after the stripping is completed, if the
stripper is to be opened, the vapor space above the resin in the stripper
must not exceed "the opening of equipment standard." After it has been
established that the resin meets the 400 or 2000 ppm requirement, vinyl
chloride escaping into the vapor space will not have to meet the openinq
of equipment standard. In the case where stripping is done in the
reactor, the same principle applies, except that the vapor space above
the resin has to meet the "reactor opening" requirement immediately
after stripping. J
9. VC-34
Comment: A paragraph should be added to §61.64(e) to permit the
use of control devices in lieu of stripping to meet the requirement
for sources following the stripper in polyvinyl chloride plants.
Response: This provision has already been made in §61.64(e)(2).
10. VC-12
Comment: The vinyl chloride emission sources following the stripper
should also have vinyl chloride emission limits in addition to
residual vinyl chloride limits in the processed vinyl chloride resin
Emission sources following the polyvinyl chloride resin stripper
account for 46 percent of a polyvinyl chloride plant's vinyl chloride
emissions. It is important to have emission standards that can be
readily measured and enforced for these emission sources.
Response: Stripping the residual vinyl chloride content of dispersion
resins to 2000 ppm and other resins to 400 ppm achieves essentially
tne_same amount of emission reduction from sources following the
stripper as installing add-on control devices. Therefore, there is
no benefit in requiring add-on control devices as well as stripping.
With regard to the enforcement aspects, there are multiple stacks
on the sources following the stripper. Essentially all the emissions
from these stacks are due to vinyl chloride left in the resin after it
2-44
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is stripped. Measuring the residual vinyl chloride in a sample of
stripped resin is much easier than measuring the emissions from
multiple sources following the stripper, and provides the same
information.
11. VC-21, VC-22, VC-25, VC-29, VC-31, VC-35
The proposed standard requires that in the case where
continuous stripping is used, "one representative sample of
polyvinyl chloride resin is to be taken for each grade of resin
processed or at intervals of 8 hours for each grade of resin which is
being processed, whichever is more frequent."
VC-21, VC-22, and VC-29 request that the 8 hour requirement
be changed to 24 hours. The rationale for this request is that
instrument charts for a continuous stripper reflect adequately the
degree of control attained over the process, and in a system operating
properly, a single sample per day is adequate.
VC-25 requests that for batch stripping one sample be taken
at random for each eight hours of operation. The rationale for
this request is that the proposed standard discriminates against
a plant which strips batchwise as opposed to a plant which has
continuous stripping. The plant with batch stripping would have
to analyze more samples.
VC-31 requests that samples be required only once per day.
According to VC-35, there are no criteria or guidelines
provided for determining the number of strippers and samples
and the types and grades of resin to be sampled for each
individual plant. Therefore, the standard is vague and may be
1 eft open to negoti ati on.
Response: The proposed standard requires that the vinyl chloride
in the stripped slurry samples be measured both during the initial
emission testing within 90 days of the effective date (unless a
waiver of compliance is obtained) and on a continuous basis. There
are no criteria or guidelines provided for determining the number
of strippers and samples and the types and grades of resin to be
sampled during the initial testing period. At one time, EPA considered
requiring one sample of each grade and type of resin manufactured at
the plant. However, this could be disruptive to production schedules
and does not seem necessary because of the continuous sampling required.
For the continuous sampling, there are specific requirements. One
sample is to be taken for each batch of each grade and type of
resin stripped. One sample is required for each batch of resin
stripped because the degree of emission reduction achieved through
stripping is primarily dependent on the procedures carried out rather
than a -control device. The vinyl chloride levels in the stripped
resins are permitted to be averaged over a 24-hour period. A daily
resin sample would give no assurance that the 24-hour average level
was being met on a continuous basis.
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12. VC-25, VC-29, VC-34
Comment: Increase the averaging time for stripping from 24 hours
to 30 days. With the 24 hour averaging time, a plant manager would
have to balance production based on meeting the standard rather than
on what customers had ordered.
Response: As stated in the preamble to the proposed standard, EPA
rejected the option of extending the averaging time to a month
because this would permit higher peak emission levels than averaging
on a 24-hour basis. EPA has already provided the industry with
considerable flexibility by allowing an averaging time of 24 hours
2-46
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2.4.5 §61.65(a)
1. VC-21, VC-26, VC-29, VC-31
Comment: A zero emission limit is proposed for relief discharges which
can be prevented. According to the preamble to the proposed standard,
operator error is to be considered preventable. This statement goes
beyond normal legal responsibility based on, negligence. A plant manager
may be held responsible only if an operator is improperly trained.
Errors in human judgment, however, are beyond complete prevention.
Response: Whether an operator error will be considered preventable
or not will have to be decided on an individual basis depending on the
surrounding circumstances. Examples of preventable operator errors
would be errors due to lack of training or negligence.
2. VC-42
Comment: It is recommended that §61.65(a) on relief valve discharges
be amended to require that all relief valves in vinyl chloride service
in ethylene dichloride, vinyl chloride, and polyvinyl chloride
plants be required to discharge to flares capable of combusting all
vinyl chloride received.
Response: There are several ways of limiting relief valve discharges
to the atmosphere. One of these is flares. EPA is concerned only
that these discharges are eliminated. If a plant successfully employs
other methods to prevent the discharges, there is no apparent reason
to require flares in addition to the other methods.
3. VC-20
Comment: EPA should require the owner or operator to report by
telephone any emergency discharge into the atmosphere from relief
valves immediately rather than within 10 days, to be followed by a
complete written report of the accident within 10 days.
Response: There is no apparent benefit to be gained by requiring the
plant to immediately report a discharge. This would not result in
reduced emissions or reduced community exposure. Enforcement action
would await the written report in 10 days anyway.
4. VC-18
Comment: Thermal relief valves activate very seldom and emit little
vinyl chloride when they do. Some of these are located in remote
parts of the plant and can be tied into a control device only with
difficulty. The benefit for doing this will be insignificant. EPA
2-47
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should exempt these remote thermal relief valves from the
toallrelifv Sta"dard f°r rel1ef valve discharges applies
to ail relief valves on equipment in vinyl chloride service FPA
'
others .
d a
2-48
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5. VC-24
damage occurring as a result
should not be subject to the
Comment: §61.65(a) should be amended to clarify that the term
"emergency relief discharge" includes steps necessary to repair
of such discharges and that such steps
emission limitations contained in the
regulations. For example, a rupture disk will be damaged as a
result of a discharge from an emergency system. Steps taken to replace
the rupture disk could involve evacuation of a portion of the vinyl
chloride remaining in the equipment. The limitation upon emissions
from opening of equipment should not apply to this situation.
Response: Steps necessary to repair damage occurring as a result of
emergency relief discharges are not exempt from emission limitations
contained in the regulations. Emergency relief discharges are
discharges which cannot be prevented. Steps taken to repair damage
after a discharge are deliberate and planned and the emissions can
be prevented or at least reduced.
6. VC-39
The proposed standard defines "emergency relief discharge" as a
discharge which could not have been avoided by taking all available
measures to prevent the discharge." (Emphasis added) Our contention is
that our facility contains sufficient features to satisfy the "all
available measures" provision. The following is a summary of the features
in our polyvinyl chloride plant which collectively prevent reactor
relief valve discharges.
1. Computer control with automatic transfer to back-up computer.
2. Total back-up analog instrumentation with the "bumpless" transfer.
3. Two sources of electric power.
4. Two emergency generators.
5. Automatic restart of critical motors following a power interruption.
6. A 200,000 gallon reservoir of refrigerated water for controlling
reactor temperature.
7. Inverter powered control of instruments and computer.
8. Computer actuated chemical system for stopping the polymerization
reaction.
9. Computer controlled peak shaving system for reduction of excess
reactor pressure.
10. Use of a reactor size vessel in the recovery system for collection
of gas surges and thus prevention of reactor over-pressuring.
2-49
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11. Computer monitoring and alarm of pressure and temperature for
abnormal conditions.
12. Computer automatically starts maximum cooling water to the reactor
if the pressure reaches a specified level.
13. Computer shuts off all reactor charging operations if a high level
occurs.
As can be seen from the above list, we feel we have provided many
features not mentioned in the regulations.
In §61.65(a) "necessary" should be substituted for "all available"
as follows:
"An emergency relief discharge means a discharge which could not
have been avoided by taking (all available) necessary measures to
prevent the significant likelihood of a discharge.
Response: The standard has been revised by deleting "all available"
measures." EPA has listed several methods which it expects a plant to
take in preventing discharges. EPA's primary concern is that the
discharges are prevented. If a company has alternate methods which do
prevent discharges, these are acceptable to EPA.
2.4.6 §61.65(b)(l)
1. VC-21, VC-24
Comment: The emissions from loading and unloading lines are insignificant.
Section 61.65(b)(l)(i) imposes too stringent a limitation upon emissions
from loading and unloading lines. VC-21 states that the allowable vent
from three cars a day at an average-sized polyvinyl chloride plant with
small cars will be 0.09 kg (0.2 Ibs). Using 7.6 meter (25 foot) connecting
hoses with three cars a day the vent at 760 mm pressure would be less
than 0.9 kg (2 Ibs) per day. The extra handling necessary with valve-
to- valve coupling at the car is hardly worthwhile. VC-24 states that
the necessity for connecting the unloading line to a pressure or vacuum
source in order to comply with the proposed standard creates increased
danger of an uncontrollable discharge of vinyl chloride.
Response: The quantity of emissions from each fugitive emission source
may appear to be relatively small, but is being regulated because
when the emissions from all the sources are considered together, they
are relatively large. EPA feels that best control technology has
been considered in developing this section of the proposed standard
and that the increased danger of vinyl chloride monomer discharge is
minimal.
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2. VC-31
Comment: The requirement for loading and unloading lines should
not be applied to pipeline delivery of vinyl chloride. To
obtain a residual of as little as 0.0038 m (0.13 ft ) of vinyl
chloride in a substantial length of pipe would be exceedingly difficult.
Moreover, it does not seem necessary since they are not disconnected
and opened with each loading and unloading.
Before opening a pipeline to make repairs (necessitated by a
leak or corrosion, for example), the line is purged and drained of
its contents to eliminate fire hazards. This is done by evacuating
the residual vinyl chloride vapor in a long pipeline below 2 percent
of its volume, except by venting to the atmosphere. Achieving the
0.0038 m residual level would require the installation of a number of
valves. Proper design, however, requires that the number of
valves be kept at a minimum, since valves are a principal source
of fugitive emissions in a pipeline.
The standard for unloading lines and loading lines should be
changed so that the vinyl chloride has to be reduced to 0.0038 m or
2 percent, whichever is greater.
Response: Since pipelines are not opened on a routine basis, the
standard has been revised to exclude them from meeting the
requirement for unloading and loading lines in §61.65(b)(l). When
pipelines are opened, they are required to meet the opening of
equipment standard in §61,65(b)(6).
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3. VC-36
Comment: Unloading lines from river barges should be given special
consideration due to the greater volume of vinyl chloride unloaded
h°L5 5argeBc?m2c/uwVw^a rail car or truck" A sentence should
be added to §61.65(b)(l)(i) so that the vinyl chloride,in unloading
lines from barges would have to be reduced to 0.0038 m6 (0.13 ft3) at
standard temperature and pressure per 225,000 kg (500,000 Ib) of vinyl
chloride unloaded.
Response: The standard is based on best control technology to
minimize emissions. The standard as a whole will result in greater
emissions from a larger plant than from a small plant. The same
principle applies to unloading lines.""
2.4.7 §61.65(b)(3)
1. VC-21, VC-25, VC-29
Comment: No account has been taken of the use of reciprocating com-
pressors which are widely used in the industry. Section 61.65 (b)(3)(iii)
should be retitled "Rotating Compressors" and a new paragraph (b)(3)(iv)
should be inserted entitled "Reciprocating Compressors" with wording
essentially the same as paragraph (b)(3)(ii).
Response: This provision has been added to the promulgated standard.
2. VC-24
Comment: §61.65(b)(3) should contain additional language to the
effect^that direct venting of gases from seals to a control device
is equivalent to utilization of double mechanical seals. The
general provisions for demonstration of equivalent emission control
equipment would require a decision by the Administrator for each
plant. This process is cumbersome and unnecessary.
Response: The two are not equivalent. Control devices control
to around 10 ppm while a properly operated double mechanical seal
would have essentially no emission losses.
3. VC-25, VC-27
Comment: EPA should withdraw the requirement of using double
mechanical seal pumps in place of single seal pumps now used.
According to VC-25, this could be done by limiting the requirement
for double mechanical seals to pumps handling liquids containing
more than 50 percent vinyl chloride by weight (rather than 10 percent,
as proposed). This should be done for several reasons:
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(1) The emissions from a single mechanical seal pump are
very small. An average single pump with a single mechanical seal
and handling refined vinyl chloride would emit only 0.0033 percent
of the 16 kg/hr which EPA calculates an average plant will emit
after the standard is in effect. A single pump with a single
mechanical seal pumping a liquid containing 10 percent by weight
vinyl chloride would emit 0.00033 percent of the target 16 kg/hr.
(2) Single mechanical seals have a reliability factor of
0.90 - 0.95, if properly fitted for vinyl chloride service. Double
mechanical seals and their attendant flush holders, filters and
gauges are estimated to have an overall system reliability of
0.70 - 0.80. To insure the integrity of the overall unit, redundancy
of such pump systems would be required, with comparatively insignificant
reduction of vinyl chloride emissions estimated to result.
Mechanical seal systems on resin slurries and solutions are
even more prone to failure than average because the resinous
materials tend to foul the pressure springs and the moveable seal
face preventing proper automatic wear adjustment. The proposal
to limit the use of double mechanical seals for liquids containing
50 percent or more vinyl chloride would exempt resin slurry or
solution pumps from regulation.
(3) In the case of pumps required to transfer specification
quality vinyl chloride through pipelines in the process unit or
in loading operations, the inclusion of minute quantities of
"an environmentally acceptable fluid such as ethylene dichloride"
designed to flow into the pump, not out of the pump," would
obviously contaminate the product and require purification facilities
to remove such impurities or the use of alternate means to preclude
the possibility of product contamination. Such measures would
be expensive and create operation monitoring parameters now not
envisioned, with further high costs attendant with them.
Response: EPA is aware that each fugitive emission source, such
as one pump, taken by itself causes relatively small emissions.
Fugitive emissions considered as a whole are a significant source
of emissions, and the goal of the standard is to reduce these.
The 10 percent figure was selected as a means of distinguishing
between equipment which handles vinyl chloride and that which does
not.
Double mechanical seal pumps are used industry-wide for emission
reduction. Where these pumps are not applicable, seal!ess pumps have
been used.
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2.4.8 §61.65(b)(4)
1. VC-29, VC-22
Comment: Section 61.65(b)(4) requires the installation of a
rupture disc preceding the relief valve on equipment in vinyl
chloride service. The preamble to the proposed standard states that
"an equivalent method of control would be to connect the discharge
line from a relief valve to process equipment or to a recovery
system." This stated equivalent method should be included as
part of the regulation so that the regulation would be complete
in itself and not be dependent on the preamble for interpretation.
Response: In accordance with this suggestion, §61.65(b)(4) has been
modified as follows: "Vinyl chloride emissions due to leakage from each
relief valve on equipment in vinyl chloride service are to be minimized
by installing a rupture disc between the equipment and the relief valve,
or by connecting the relief valve discharge to a process line or recovery
system, or equivalent as provided in §61.66."
2. VC-25, VC-26
Comment: The requirement in §61.65(b)(4) for installation of rupture
discs between relief valves and the equipment served by the relief
valve should be removed, or revised to provide for the alternative of
having a formal program of relief valve testing and maintenance. This
should be done for several reasons.
(1) A properly selected, installed and maintained relief
valve is less likely to leak than a rupture disc.
(2) The rupture disc prevents the relief valve from suffering
premature lifting and also eliminates the chatter or sporadic
relief that can occur when the vessel is near relief pressure and
the valve doesn't reseat properly. However, when the rupture disc
fails, pieces of the failed disc could more than likely wedge the
relief valve open and cause relief valve failure. This, then, would
cause the emission of more vinyl chloride than chattering or premature
relief which can be cured by dropping system pressure.
(3) A dangerous situation will arise if the rupture disc
slowly leaks vessel pressure into the space between it and the relief
valve, thus effectively raising the relief pressure by 100 percent.
Venting the space between the rupture disc and relief valve will
avoid this situation, but creates another potential emission source.
Response: The proposed requirement for rupture discs is not being
changed. There is apparently a difference in opinion as to whether
relief valves leak more than rupture discs. Routine maintenance of
2-54
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relief valves may reduce leaks. However, in EPA's judgement relief
valves do tend to leak more than rupture discs, and the addition of the
rupture discs will reduce emissions. Preventing the leaks frpm
relief valves in the first place appears to be a more efficient way
of reducing emissions than detecting the leaks after they have
already occurred.
In regard to the second point that pieces of a fragmented rupture
disc can wedge relief valves open, modern rupture discs are designed
so they do not fragment. Knife blades can be placed above the disc
or the disc surface can be scored. When pressure is exerted on the
disc, the disc divides into equal pie-shaped sections .without
fragmenting.
A slow leak between the rupture disc and the relief valve can be
detected with a pressure gauge or by venting the space between the
disc and valve and checking for leaks from the vent. Venting the
space between the rupture disc and relief valve does create another
potential source of emissions. However, since the rupture discs are
less likely to leak than relief valves, the emissions from the vent
are less than if there were no rupture disc.
3. VC-35
Comment: In addition to requiring the installation of a
rupture disc between the equipment and the relief valve, a
pressure gauge is recommended to be required between the rupture
disc and the relief valve so that rupture disc leaks or ruptures
are readily apparent, especially where relief valves may not
relieve, yet leakage could occur and go undetected.
Response: The use of a pressure gauge between the rupture disc
and the relief valve is recommended in the SSEIS, Vol. I. Pressure
build-up between the rupture disc and relief valve could prevent the
relief valve from relieving when it should. Therefore, the pressure
gauge is needed to protect the equipment that is serviced by the relief
valve. Since the pressure gauge is needed primarily for safety
reasons rather than emission control, EPA has highly recommended
it but does not require it.
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2.4.9 §61.65(b)(5)
1. VC-14, VC-18, VC-21, VC-25, VC-26, VC-27, VC-28, VC-29, VC-34
Comment: A provision for emergency manual venting should be added to
§61.65(b)(5). Discharges from relief valves in polyvinyl chloride
plants are controlled by methods including, but not limited to,
proper instrumentation, injection of chemicals, and the manual venting
of gases to the monomer recovery system or other stand-by methods.
Use of these techniques is the primary response to a reaction upset.
When these actions fail to establish desired temperature and
pressure, a hazardous condition is created. As pressure and temperature
rise toward relief ratings, the rate of reaction more than doubles for
every 10 C rise and the degree of being out of control becomes a geometric
progression. For this reason the quantity of vinyl chloride evaporated
in order to gain control of the reaction at burst pressure is significantly
greater than that needed to regain control at lower pressures and temperatures
via the manual technique.
Use of manual venting to the atmosphere recognizes this problem
and relies on vinyl chloride evaporation to cool the reactor contents.
Manual venting can permit the reactor to be brought under control
more quickly. Since the manual valve can be completely closed, a
lower total quantity of vinyl chloride will be emitted to the
atmosphere. Once a relief assembly, including rupture disc and
relief valve, functions it is not certain that the relief valve
will reseat; this would permit continuing emissions of vinyl chloride.
It is estimated that manual venting will reduce potential emissions
by 50 to 80 percent.
The proposed standard prohibits manual venting of vinyl chloride
to the atmosphere, even in cases of extreme emergency. It is
conceivable that there will arise on very infrequent occasions the
necessity for doing this. An example could be in the case of
failure of abatement equipment or very severe weather, such as a
tornado, which has so badly damaged the plant that the installed
safety equipment is inoperable, and manual venting of a small part of
the reactor charge could prevent the uncontrolled venting of the
entire charge. Such occurrences are not expected to happen more than
once in a few years, but when they do, operators should not be
forbidden to exercise good judgment. The required reactor chart
record will show when this has happened, and the owner should report
the occurrence, just as in the case of a relief valve release.
Accordingly, the use of manual venting to the atmosphere should
be permitted after all normal controls have failed, but prior to
the use of the last resort, the emergency relief device. It must
be understood that this assembly is a primary device for preventing
a major catastrophe, the rupture of a reactor.
2-56
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It is not practical to construct a gasholder or abatement
device large enough to handle all of the monomer from all of the
reactors in a plant or even one Targe reactor.
VC-25 gave an example of how mahual venting was use'd to
control the pressure arid temperature in a vinyl acetate copolymer
reactor when the short stop addition system failed to function. The
reactor became uncontrollable at 6:20 a.m. Two additions of
refrigerated water failed to restore control. At 7:35 a.m., with
the pressure at (195 psi) a'nd rising sharply, tire reactor 'was
vented to the air. The reactor rupture disc Would have failed at
220 psi anyway and no later than, 7:40 a.m. based on the slope of
the pressure curve. The material discharged from the vent was
semi-solid; thus, any vent recovery system would shortly haVe
been inoperative and the operating status of relief valves Highly
questionable.
Response. The standard has been revised to allow emergency
manual venting. Emergency manual venting could be used in
situations like the one where a tornado damaged the safety
equipment in the plant, but not in situations like the one
described by commentator VC-25. In the situation described by
commentator VC-25, the reactor contents could be vented to a
gasholder.
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2.4.10 §61.65(b)(6)
1. VC-29
Comment: EPA discusses vacuum as a means of meeting the opening of
equipment standard. The assumption that larger pressure vessels will
withstand vacuum is incorrect. Many will not, despite a substantial
pressure rating; this leaves water purge as the only practical method of
gas removal. This can be very difficult on a remote tank in cold weather.
Response: These statements are correct. Even though these problems do
exist, EPA feels that technology does exist for meeting this part of the
standard and it should be used. Plants have several options for meeting
the standard including the ones named and also purging with nitrogen.
2. VC-20
Comment: Fugitive emission sources are the largest sources of
emissions to the atmosphere. We therefore question the rationale
of the proposed standard which requires that the vinyl chloride
concentration in process equipment greater than or equal to 5,500
liters in volume be reduced to two percent by volume at standard
pressure and temperature before the equipment is opened to the atmos-
phere, and 110 liters of vinyl chloride at standard temperature and
pressure for reactors smaller than 5,500 liters. There appears to be
incongruity in logic to allow such high emissions from fugitive sources,
the most important source, and only 10 ppm for other sources. EPA
should also clarify how these measurements are to be made.
Response: There are three points made in the comment. The
responses to these are as follows:
1. The cut-off point of 4.75 m3 (5,500 liters) was chosen
for several reasons which were explained in the preamble to the
proposed standard. However, the cut-off point does not apply
to reactors. Since reactors have traditionally been opened much
more frequently than other process equipment, a separate
standard was proposed for the opening of reactors in §61.64(a)(2).
2. The 10 ppm limit and the limits for opening of equipment
are each based on best control technology. The 10 ppm limit is
to be met through installation of control devices. The limits for
opening of equipment are to be met by procedures such as evacuating
or purging the vinyl chloride out of the equipment. The vinyl chloride
removed from the equipment must also be treated in a control device
2-58
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and meet the 10 ppm requirement. The overall mass emissions from
opening of equipment will be smaller than the emissions
from stacks meeting the 10 ppm requirement, because the equipment
is opened on an infrequent basis for insnection a,nd maintenance.
The emissions from opening of equipment can be calculated. If
vacuum is used, for example, the calculation would be based on the
number of evacuations, the vacuum involved, and the volume of gas
in the vessel. If the vessel is purged, the vinyl chloride concentration
in the equipment can be measured and the total vinyl chloride emissions
calculated based on the volume of gas in the vessel.
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2.4.11 §61.65(b)(7)
1. VC-21, VC-22, VC-25, VC-26, VC-27, VC-29
Comment: The use of the word "no" in §61.65(b)(7) is inappropriate
because the prohibition is impractical, if not impossible to enforce.
However, there is no argument with the spirit of the provision, and the
following revision is suggested:
"(7) Samples: Unused portions of vinyl chloride samples
shall be returned to the process or to an abatement device,
and sampling techniques shall be such that sample containers
are purged into a closed process system."
Response: The suggested change has essentially been incorporated into
the promulgated standard. This revision is only a change in wording and
does not represent a change in the level of control required to meet the
standard.
2. VC-18
Comment: This part should be changed to allow the plant to take vinyl
chloride samples any way they choose so long as vinyl chloride emissions
are minimized for instance by scrubbing them in a proper control device.
Response: The purpose of this section is to prevent emissions during the
collection vinyl chloride samples. It is unclear how a control device
could be used to achieve the same goal.
3. VC-29
Comment: The standard for sample flasks is applicable only to liquid
chemicals such as vinyl chloride monomer sampling in vinyl chloride
plants. Consideration should be given to routine and non-routine
sampling. EPA should consider limiting the scope of this control to
routine samples containing 20 percent or more vinyl chloride monomer by
weight.
Response: The standard has been revised to cover samples containing
10 percent or more vinyl chloride by weight. This is consistent
with the other fugitive emission regulations which apply to
equipment "in vinyl chloride service."
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2.4.12 §61.65(b)(8)
1. VC-43
Comment: A plant operated by the commentator produces a
dry, unrefined ethylene dichloride product and any vinyl chloride
produced is basically a minor by-product. The requirement for
a continuous leak detection system, as described in §61.65(b)(8)
(i-iii) is felt to be unnecessary and would serve a very limited
function when compared to its cost, installation and maintenance^
A periodic, manual monitoring program would be a more equitable
alternative.
Response: The leak detection program is required only for equipment in
vinyl chloride service. "In vinyl chloride service" means that a piece
of equipment contains or contacts either a liquid that is at least TO
percent by weight vinyl chloride or a gas that is at least 10 percent by
volume vinyl chloride. EPA has discussed this provision with the
commentator. There is no equipment in this particular plant which is
"in vinyl chloride service."
2. VC-31
Comment: The proposed standard does not give a clear definition of
leak. By inference, any measurement by the vinyl chloride detection
equipment which shows a higher background level than normal is
construed to indicate a leak. A better proposal would be to
define a leak as a measurement of greater than 25 ppm. This would
minimize the continuous search for very small leaks which do not
materially increase emissions.
Response: EPA considered including a definition for leak in the
proposed standard. From an enforcement viewpoint this would be
a preferable approach. However, the background concentrations in
plants are expected to vary depending on the size of reactors, the
age of the plant, the layout of the plant, and whether the plant
is open or enclosed. The background concentrations are expected
to decrease as engineering controls are implemented to meet the
Occupational Safety and Health Administration standard. The higher
the concentration defined as a leak, the less regulation of the
smaller leaks. Twenty-five ppm is relatively high. EPA visited
one newer plant which defined 0.5 ppm as a leak detection level. It
is doubtful that this background concentration will be achieved
at all plants by the time the standard is promulgated. Therefore,
EPA has decided to define leak on a individual basis at each plant
depending,,on the measured background concentrations.
2-61
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3. VC-31
Comment: It is recommended that leak patrols using the portable monitoring
system be done on a regularly scheduled basis rather than continuously.
A weekly patrol should be adequate for this function with the detection
equipment doing the monitoring between patrols.
Response: Both the proposed and promulgated standard require only
that the portable hydrocarbon detector be used routinely rather than
continuously to find small leaks.
4. VC-26
r ''
Comment: Preparation and submittal of a specific leak detection and
elimination system within 45 days is a very short period. It should
be extended to at least 120 days. The establishment of new
monitoring points, assembly of equipment and training of laboratory
personnel will require at least 4 months.
Response: The proposed and promulgated standards require only that
a description of the leak detection and elimination program be
submitted to EPA within 45 days after promulgation of the standard.
This will allow EPA to review the program and approve or disapprove
it before it has to be implemented. The program has to be implemented
90 days after the standard is promulgated.
5. VC-18
Comment: In §61.65(b)(8)(vi) the standard has a provision for each
operator to develop a definition for a leak using some measure of
vinyl chloride concentration above background levels in the fixed
point monitoring system. This approach is inoperable because
(1) changes in wind direction and other weather conditions will cause
the background levels at some monitoring points to fluctuate widely
and (2) the intermittent batch nature of normal polyvinyl chloride
operations will cause wide variation of vinyl chloride concentrations
depending on what operations are occurring. This will cause the
background variation to be similar to the vinyl chloride increment
measured when a leak occurred, so it would be difficult to separate
a leak from fluctuation of the normal background. EPA should delete
this section and let each plant handle how leaks shall be detected.
Response: In EPA's judgment, the fact that leak will be defined
on an indivudual basis for each plant provides the flexibility
needed to account for these variations.
2-62
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6. VC-20
Comment: EPA should specify that companies are required to keep
permanent records of the leak detection results. There should also
be scheduled service, maintenance and calibration of leak detection
equipment. These records must be subject to inspection upon
request. EPA should also establish a level of vinyl chloride not
to be exceeded and require reporting violations by the owner or
operator when they occur.
Response: EPA requires that the records of leak detection results
be kept for two years. The purpose of the leak detection program
is to ensure that emissions from leaks are minimized by detecting
them and correcting them as soon as possible after they occur.
Keeping the leak detection results for longer than 2 years would
not serve this purpose.
Section 61.65(b)(8) of the proposed standard requires that each
leak detection program include a calibration and maintenance schedule
for the leak detection program which is acceptable to the Administrator.
In the promulgated standard a sentence has been added which
specifies that the continuous monitoring system is to be calibrated
daily using the same calibration gases which are required for
Test Method 106.
The reason EPA has not established a level of vinyl chloride
not to be exceeded is explained in comment number 2 in this section.
The standard does not require the owner or operator to call EPA when a
leak is detected for several reasons. First, the purpose of the program
is to find sources of leaks and redesign equipment to reduce leakage
from these sources and to correct leaks that do occur as soon as possible.
A plant owner does not violate the intent of the standard by having a
leak, but by not correcting the leak. EPA expects leaks to occur.
Also, leaks occur relatively frequently and it would be burdensome for
both the plants and EPA if all the plants called EPA when a leak occurred.
2-63
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2.4.13 §61.65(b)(9)
1. VC-14, VC-17, VC-18, VC-21, VC-22, VC-26, VC-28, VC-29
Comment: It is recommended, that the first sentence of this
section be changed to read as follows:
°f Vlnyl Ch1on'de In each inprocess waste-
9re^er than 10° Ppm vinyl c^lon'de measured
n a Piece of equipment shall be reduced to
less than 10 ppm by weight before being mixed with any other inprocess
wastewater stream which is 10 ppm or less; before being exposed to
ged to a wastewate? treatment
U"treated as a "abater. This
stand-1! pr°P°s!d to Clar1fy the standard. Presently the
standard can be interpreted to require stripping all wastewater
streams separately. The intent to prohibitPLpliancrthrough
thai ihe Inn"™31!! ,h" ^ r^^ wrd^- Jt ** a^o requested
has to be treated cut-°ff P°lnt that determines which wastewater
nf th - ^eded to be clarified. The
intent of the standard was to prevent dilution rather than require
has bLn ^±ef °f 1ndiv1dual s^eams. The promulgated standard
if retlinld aS suggested' excePt that the 10 ppm cut-off point
2. VC-13, VC-21
Comment: According to commentator VC-13, the definition of
HpJfnpf^ wastewater" would be more clear and concise if it was
defined as water which contains greater than 10 ppm of vinyl chloride
as it eaves any piece of equipment." VC-21 suggests removing
C°nde f™ '^process wastewater"
vinyl hlride."
-
9
definition of
SayS
containing
Response: The purpose of the rather complicated definition of
^hn-f^^15^0 d1st1n9"ish ^tween wastewater that is
K 5 standard and wastewater which is discharged to a
»P ?nd.ls,suWect to EPA's effluent guidelines and
Polyvmyl chloride" is included in the definition
chlor1de aiways contains at
ta
standards.
2-64
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3. VC-23
Comment: EPA proposes to limit the concentration of vinyl chloride
in inprocess wastewater to 10 ppm or less. However, EPA has not
sufficiently investigated the more attractive possibility of recycling
inprocess wastewater.
Response: The 10 ppm limit provides incentive for recycling because
of the cost involved in treating the water. See Section 2.8, Comment
No. 1.
4. VC-14
Comment: As noted in the preamble, steam stripping is the most
suitable device for reducing vinyl chloride in inprocess wastewater.
Section 61.65(b)(9) requires that the overhead from the stripper be
routed to a furnace for further treatment. Neither does the data
contained in the SSEIS, Vol. I support, nor do we know of
any data which supports, the achievement of a 10 ppm bottoms stream
from a stripper which is also producing an overhead product suitable
for incineration. The standard should be revised to require the
concentration of vinyl chloride be reduced to 25 ppm instead of 10 ppm.
Response: If the overhead from the stripper alone cannot support
combustion, it can be blended with concentrated hydrocarbon wastewater
streams or supplemental fuel. It is not apparent how revising the
standard to 25 ppm would solve this problem.
5. VC-37
Comment: Activated carbon is available as a method for reducing
vinyl chloride concentrations in wastewater. A reliable manufacturer
of resins who develops systems on a proprietary basis has informed
me that a pilot plant has been effective in cleaning up ethylene
dichloride (a closely related material) from water. With 0.2 percent
(2000 ppm) in the intake wastewater they were able to clean the water
up to 0.05 ppm and steam off the catch for reuse of the product gas
and reuse of the resin. Because no bench or pilot tests have
been run with vinyl chloride in wastewater, it is important that
work be done at once with vinyl chloride.
Response: EPA appreciates the information provided by the commentator.
Before making the emission limit for inprocess wastewater more
stringent, and in effect requiring activated carbon as the control
measure, as suggested by the commentator, EPA would have to conduct
studies on the effectiveness of activated carbon on reducing vinyl
chloride concentrations in water. This would delay standard setting.
EPA may conduct these studies at a later date. Meanwhile plants
could employ activated carbon instead of waste stripping to meet the
standard.
2-65
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2.4.14 §61.66
1. VC-32
Comment: The right to use equivalent methods should be indicated
clearly in the standards without reliance on reference to the
preamble. This is especially true in the area of analytical
methods, where no two laboratories ever follow precisely the
same techniques, and in methods used to reduce fugitive emissions.
Insistence on a single method discourages innovation in the
development of improved technology.
Response: Provision for equivalent control methods for fugitive
emissions is included in §61.65(b) and §61.66 of the proposed standard.
Provision for equivalent test methods is included in §61.67(g).
2. VC-24
Comment: The standard should include guidelines that the Administrator
will use in determining that a proposed control method produces an
equivalent emission reduction. A procedure for contesting this
determination should also be specified.
Response: Since there are many parts of the standard where equivalent
methods are allowed and because the nature of the equivalent methods
is unknown at this time, it would be difficult to write guidelines
which would be applicable to all situations. -Providing for a procedure
for contesting EPA's determination could indefinitely delay the
installation of controls.
3. VC-18
Comment: A sentence should be added to §61.66 indicating that if
EPA does not act upon a request for an equivalent control method
within 90 days, the requesting operator should be allowed to
proceed with his alternate.
Response: If an owner or operator chooses to request to use an
equivalent method of control for initial compliance with the standard,
he must do so within 30 days of the effective date. He should at the
same time submit a request for waiver of compliance pursuant to section
112(c)(l)(B)(ii) of the Act. The request for waiver of compliance
should provide for the case where a control method is determined not
to be equivalent, and time is required to install another type of
control. The two year deadline cannot be exceeded in any event.
Of course, an owner or operator can request to use an equivalent
method sometime in the future to replace the method he used for
initial compliance. In this case, there is no deadline for
submitting a request for using an equivalent method. The old method
of control can be used until EPA determines whether the new method
is equivalent.
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2.5 Testing, Reporting, Recordkeeping
2.5.1 §61.67
1. VC-13, VC-21, VC-26, VC-27, VC-29
Comment: Section 61.67(c) of the Emission Tests should be amended
to eliminate the requirement that emission tests be conducted
under the maximum production rate at which the equipment will be
operated. The reason for the requested change is that the maximum
production rate of a plant under optimum conditions may not be
feasible or safe at the time of the test. Flexibility under conditions
existing at the time must be allowed to insure that operator safety
and public welfare is protected. Unique operating constraints may
also require that tests be performed at levels well below maximum
rates, owing to individual processes, which would require the
Administrator's approval.
Response: The only scheduled emission test is the initial test
that is required to show that the plant is in compliance. After
that, tests are performed only at the request of EPA. Since tests
are likely to be required relatively infrequently, it does not seem
unreasonable to request a plant owner to schedule his operations as
required for the test. The purpose of the test is to observe whether
the control equipment is sufficient to keep the emissions below the
standard when it is operating at its peak load. If the standard
is met under these conditions, it can be more readily assumed
that the standard is being met on a continuous basis. It should
be noted that testing is not required during maximum operation of
the equipment, but only "while the equipment being tested is operating
at the maximum production rate at which the equipment will be_ operated."
(emphasis added)
2. VC-11
Comment: In regard to the 10 ppm concentration standard for several
of the stack emission sources, including the specifications for averaging
time, oxygen content, and moisture content would clarify compliance
determination.
Response: The averaging time is specified indirectly through Test
Method 106. Section 61.67(a)(g)(1) specifies that Test Method 106 is to
be used for those emission points that have a 10 ppm concentration
limit. Test Method 106 requires that an integrated bag sample be collected
for a minimum of one hour three times. This means that the emissions
are averaged over a period of at least three hours. A specification has
been added to the promulgated standard which would require that a time-
weighted average be used, if the three runs are of different length.
In the proposed standard, the concentration of vinyl chloride was to
be corrected to 10 percent oxygen (wet basis) if combustion were used
as the control measure. In the promulgated standard, this requirement
has been expanded to all control measures.
2-67
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3. VC-20, VC-25
S°?!!!!"t: .The frequency of emission testing should be specified.
circumstances ** 9ranted U^SS there are overriding or extenuating
nnv
y
mef urei?e^s a™ required on a continuous basis
3-d ?tnPPin9 levels. For other stack emissions,
90 davn h e"lssl°n tef 1s the 1n1«al test required within
nShP^Lc^- effectTve date (unless a waiver is obtained). Any
other testing required is at the discretion of EPA. For example EPA
may require an emission test for the monomer recovery system ?n a
polyvinyl chloride plant if emission excursions are repeatedly measured
by the continuous monitor. Waivers of emission testing are ikely to
tha?ro"-cd-°nly 1n.cases,where EPA has other substantial evidence
that emission requirements are being met.
ic -Kn4; VC~2°* uComment:
ines EPAr?hnh?/m?Unt-
lines. EPA should also i
EPA should clarify how the owner or operator
-Vlnyl Chl°ride in Ioad1n9 or unloading
icate how this will be enforced.
u to meet the ^quirement for loading
^ lines. The method for meeting the requirement is to
to EnpA°rP?hf stdanHnt°Ha Standard °Perat1ng P'ocedure'wh'ch ?s available
on a rontJnp h«?c I °Peratln9 Procedure is required to be available
SroLSS uhS;L^hthoSS».p5rsons resP°nsl'ble ^r carrying out the
procedure. Whether the method used meets the emission requirement can
0n- EP^ can enforce the sSndSd Sr^Sjh
of hP nm'nn operating procedure, through inspection
Sit She procedure ' " °U9h Observat1on of Persons carrying
5. VC-25
witin rhinH WHeth?r Cont1nuo«s measurement of emissions
with a vinyl chloride detector is required or not. If an acceptable
automatic vinyl chloride detector is in operation at a par??cu?ar
plant, emission tests should be waived. particular
Response: Continuous measurement of emissions with a vinvl chloride
detector is required for the reactor; stripper; mixing^e ghing and
SSrdf??at?nnaiv?rSi; ^^ re*COVery System; ethylene d1chl5r1dl
?eacSr- InSVhl rlS ?ride-f°rmati°2 and Purification; oxychlori nation
The vinvl ?MnHHfHor\-deV1.Ce USed for caPtured fugitive emissions.
it is ?n HP .cln dete?tSr 1S not a standardized reference method;
™ lndlca*or of emission levels. Test Method 106
1t is
2-68
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6. VC-13, VC-18, VC-21, VC-22, VC-26, VC-27, VC-29
Comment: Section 61.67(e) requires that emission test results are
to be determined within 30 days after the emission test and that
the determinations are to be dispatched to EPA by registered mail
the day following receipt of the determinations. This requirement
should be changed so that the determinations are required to be
reported to EPA by U. S. mail postmarked within 15 days following
the determination. There is no urgency in reporting such data and,
given the present state of our postal delivery system, there is no
reason for registered mail.
Response: A source is supposed to be in compliance with the standard
within 90 days of the promulgation of the standard. The proposed
standard requires that the emission tests be done within the 90 day
period, and permits an extra 30 days for determination of results.
It seems unnecessary to allow two more weeks to mail the results.
The purpose of using registered mail is to document the fact that
emission data have been sent and received. This way if the results
are lost in the mail, there will be no question that they were sent.
7. VC-13, VC-21, VC-22, VC-26, VC-27, VC-29, VC-30
Comment: . It is recommended that paragraph (c) be changed so that a
general rather than a detailed description of the method used or the
procedure adopted to insure compliance with the standard is required.
For many abatement systems employed in the industry, detailed
descriptions of the equipment, the operating conditions, and the
functional characteristics of the equipment are trade secrets and,
in many cases, patentable technology. The use of this technology
by other parties should be on a technology-fee basis which is established
by the company developing the abatement equipment. If EPA would like
additional information concerning the system, a section 114 request
under the Clean Air Act would be an appropriate approach.
Response: The promulgated standard has been revised to require a
"description" rather than a "detailed description." EPA agrees that
a detailed description is not necessary in the initial report.
Additional information can be gathered as necessary under section 114
of the Act or through inspection. If EPA does request information
of a proprietary nature, the Clean Air Act does provide for an owner
or operator to request confidential treatment of that information.
2-69
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8. VC-27
Comment: Section 61.67(g)(l)(i) should be amended to take cognizance
that it is impossible to sample the exit of a flare. Sampling of a
flare should not be required if it can be demonstrated that such
a control flare is actually operating.
Response: EPA is aware that the exit of a flare cannot be tested
with Method 106. EPA, however, has no data which indicates that
a flare is as effective as an incinerator in controlling vinyl
chloride emissions or that a flare can meet the 10 ppm requirement.
Therefore, a blanket exemption for testing cannot be granted. If an
owner or operator could provide data__to EPA that showed that a
flare could meet the standard, a waiver of source testing could be
granted on an individual basis.
9. VC-17, VC-29
Comment: In the regulation, the only mention of the option of using
a portable hydrocarbon detector for measuring reactor opening emissions
is §61.67(g)(5)(i)(B). Section 61.67(g)(l) should also state that
the portable hydrocarbon detector can be used for the testing required
in §61.64(a)(2).
Response: Section 61.67(g)(l) outlines the testing procedures to
be used for stack emissions. The test methods to be used for
reactor opening emissions are outlined in §61.67(g)(l)(i)(B).
Test Method 106 only is to be used for stack emissions.
2.5.2 §61.68 as proposed or §61.69 as promulgated
1. Comment: The Agency must realize the tremendous task it has set for
both itself and industry in attempting to take all the readings for
determining compliance on all source points, preparing the necessary
reports, requests for variances, compliance programs, and approved
procedures, forwarding these to the Administrator, receiving his reply,
and acting on the reply all within 90 days of promulgation. Total
confusion will result from even the slightest lack of coordination
in all of these frantic activities at 50 or so plants, and in the
Administrator's office. It may be wise to omit this original report,
or delay it for 90 to 180 days.
Response: Section 112 of the Clean Air Act requires that a plant
be in compliance with the standard within 90 days of promulgation,
unless a waiver of compliance is obtained. This is the basis for
requiring that emission tests be conducted within 90 days. Several
commentators have indicated that they will request a waiver of compliance.
If these results for waivers are granted, the number of emission tests
will be reduced. The regional offices rather than the Administrator's
office will be handling these various reports.
2-70
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2.5,3 §61.69 as proposed or §61.70 as promulgated
1. VC-13, VC-21, VC-27, VC-29
Comment: Section 61.69(b)(l) requires a report 180. days after the
effective date, while §61.68 requires a very comprehensive initial
report 90 days after the effective date. The magnitude of these two
reports is such that the allowable time Is insufficient, and it is
unlikely that all the facilities and procedural approvals required
for the semi-annual report will be available imme.dtately after the
effective date. It is requested, that §61.69(b)(l). be amended so
that the first semi-annual report is due 270 days after the effective
date or 180 days after the initial report, whichever comes first.
Response: The standard has been revised §p that the first semi-
annual report will not be due for at least'180 days after the initial
report. All semi-annual reports will be due on March 15 and
October 15. The first semi-annual repprt will be due after the
first full semi-annual repprt period has past since the initial report
was received. As an example, if the initial report is received by
EPA on September 15,the first semi-annual report will be due the
following March 15.
2. VC-29
Comment: To clarify the intent of the standard, §61.69(c)(2)
should be changed by substituting the words:
"(2) The owner or operator shall inplude a summary of the analytical
results on the stripped resin. Test Method 107 or equivalent is to be
used."
Response: Clarifying changes have been made to this paragraph.
3. VC-23
Comment: The monitoring and record-keeping requirements in the proposed
rules appear to be adequate.
Response: No response necessary.
4. VC-13, VC-22, VC-29
Comment: The standard requires that the vinyl chloride levels in
stripped resin be measured for each batch. It also requires that
the vinyl chloride in reactors be measured each time they are to be
opened. The preamble to the proposed standard suggested that for
both reactor opening and improved stripping, it is possible over
time to establish a relationship between the emissions measured and
certain operating parameters.. The general provisions and the
proposed standard orovide for waiver of emission tests and use of
-------
alternative or equivalent methods. The preamble stated further that
under the authority of these provisions, EPA could, on an individual
basis, permit a plant to record certain operating parameters
rather than measure emissions. The alternative of recording
operating parameters should be included in the standard rather
than mentioned in the preamble.
Response: EPA is preparing an enforcement guidelines document. It
will recommend that the appropriate enforcement officials accept
recording of operating parameters as an alternative test method
after a plant has clearly demonstrated a relationship between
measured vinyl chloride levels and certain .operating .procedures.
Recording of operating parameters is not included in the standard as an
alternative test method procedure because of the individual
differences among plants and resins. For improved stripping, for
example, specific operating conditions have to be established
for stripping each different kind of resin at each different
kind of plant. Establishment of the operating conditions
to be used for each resin at each plant are best handled on an
individual basis.
2-72
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2.6 Test Methods
1. VC-13
Comment: Method 106 was designed for isokinetic sampling of dusts and
mists, not for sampling of gases. Appropriate changes are in order.
Response: Apparently, the commentator failed to read Method 106,
as it ,has nothing to do with isokinetic sampling.
2. VC-14, VC-44
Comment: Test Method 106 is a very detailed testing procedure,
capable of determining mass emission rates from equipment. The
use of this elaborate procedure where only a concentration 'determination
is required is burdensome and unnecessary.
A properly calibrated detector for vinyl chloride can make this
determination with greater ease and equal precision for purposes of
this section. We request that this section be modified to allow
emission concentration limits to be measured with a calibrated
vinyl chloride detector where emission limits are prescribed in section
61.62(a), 61.63(a) and from the control system.
Response: Method 106 yields an emission concentration only, not a
mass emission rate.
Specification of Method 106 implies that an averaged emission
concentration determination is required for a minimum period of one
hour for each of three runs. Since it would be difficult to specify the
correct number of instantaneous readings necessary to replace a single
averaged value for each of the great variety of sources covered by the
vinyl chloride standards, the integrated sample approach must remain the
reference method. However, it is envisioned that individual sources may
wish to develop data to substantiate the equivalency of instantaneous
sample data for their processes. This data would consist of enough
duplicate instantaneous/integrated sample data to be able to statistically
determine how many instantaneous data points spread over a minimum
period of one hour would be required for the average to not be statistically
different from the integrated average values at the 95 percent confidence
level. The conditions set forth in §61.67{g) would still apply with
regard to any subsequent dispute over equivalency.
2-: 73
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3. VC-17, VC-26, VC-29
Comment: Tedlar bags are expensive ($91 each)
bags ($6 each) as alternates.
We recommend Saran
Response: While EPA has no direct experience with Saran bags for
vinyl chloride testing, data have been published which indicate a
Dag of this material could have a significant loss of vinyl chloride
The only bag material which is acceptable in place of Tedlar is
aluminized Mylar.
4. VC-17, VC-29
Comment: Section 4.3.1 of Test Method 106 specifies a strip chart
recorder for the gas chromatograph, while section 6.4 calls for measure-
ment of peak area with an automatic integrator. We believe that the
strip chart_recorder is adequate for this use and that the automatic
integrator is unnecessarily elaborate and expensive ($5200) when peak
height, triangulation and disc integrators are sufficiently accurate for
ufi 1S US6•
Response: "... automatic integrator" has been changed to "disc
integrator. For a laboratory that processes a larger number of
samples, an automatic integrator may be a worthwhile investment, and
would of course be acceptable.
5. VC-17, VC-27, VC-29
Comment: Most gas chromatographs are designed to use hydrogen and
air for their flame detectors. When so used, they are capable of
detecting 0.5 ppm vinyl chloride in air. This seems to be sensitive
enough to monitor the 10 ppm limit that the standard calls for The
replacement of air by oxygen in the combustion gas therefore seems
unnecessary.
Response: "Oxygen" will be changed to "air or oxygen, as required
by the detector.
6. VC-17, VC-29
Comment: The integrator recorder specified in section 5.3.6 of Test
Method 107 seems unnecessarily elaborate as the measuring device
Here, especially, the vinyl chloride peak is so sharp that any measure-
ment other than peak height would be difficult. A strip chart recorder
With a sensitivity of 1 millivolt full scale is adequate for this use.
Response: If sample injection time is varied for some purpose, peak
J2Sd?"ing mcy °^ur' Accordingly, it is preferable to measure
peak area. For^the number of samples that most facilities will be
analyzing, the integrator recorder specified in 5.3.6 would seem
to be a wise choice. However, manual techniques may prove to be
acceptabIe.
2-74
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7. VG-17, VC-29
Comment: Regarding 5.3.2,in Test Method 107, Supelco, Inc., Supelco
Park, Ballefonte, Pennsylvania 16823, recently announced that they are
discontinuing Carbopack A. However, they say that 0.2 percent Carbowax
1500 on Carbopack C gives the same separation of vinyl chloride as 0.4
percent Carboway 1500 on Carbopack A.
Response: Carbopack C will also be listed in 5.3.2.
8. VC-17
Comment: Regarding 7.2., 1 and 8.1 of Test Method 107, we cannot see why
water is added to dry resin samples and to the calibration vials. It
seems more logical to run the calibration standards and dry resjn
samples without water and to use Equation 107-4 when water is present in
samples.
Response: If any water is present in the sample, the water elutes
from the gas chromatograph column in a broad band, encompassing the
time the vinyl chloride is eluted. As the water affects the sensitivity
of the flame ionization detector, it was thought best to add enough
water to every "dry" sample to have a water vapor saturated gas sample
for the gas chromatograph thus insuring a reproducible amount of water
vapor in each sample.
9. VC-17
Comments: The constants in Equations 107-3 and 107-5 of Test Method
107 could not be generated from Equation 107^2 and 107-4, respectively.
M
Response: A value for V of 23.5 was used instead of 23.5 - ^—.
as published. 9 . K4
The equations were correct as published, except brackets were
missing in Equation 107-5 (See comment number 21 in this section).
10. VC-18, VC-27
Comment: Concerning §61.61(n), the definition of portable hydrocarbon
detector, the two recommendations are to relax the sensitivity requirement
from the proposed 5 ppm to 10 and 20 ppm, respectively.
Response: The definition of portable hydrocarbon detector has been
revised to relax the sensitivity requirement to 10 ppm. Based on
information supplied by Commentator VC-27, analyzers with a sensitivity
of 5 ppm "are extremely delicate and require a high level of maintenance
and considerable redundancy of units would be required." The standard
requires that a portable hydrocarbon detector be used to detect leaks and
measure vinyl chloride concentrations in equipment before opening it.
In both cases an instrument with a sensitivity of 10 ppm will be
adequate.
2-75
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11. VC-26
Comment: In the drawing on page 59550 (Figure 106-1) valves should be
provided for the sample bag; otherwise the method cannot be used.
Response: The ball check in the single bag female quick connect
seals the bag when the sample line male quick connect is removed.
12. VC-27
Comment: The suggested technique in Test Method 106 is to sample into a
Tedlar bag at ambient conditions and analyze the bag contents. Any
stream which contains large amounts of water, or saturation ethylene
dichloride at process temperature, will cause erroneous numbers for
vinyl chloride due to condensation. This would result in serious errors
in steam vent analysis. Assuming 1 percent inerts, one can postulate a
100-fold concentration of vinyl chloride into the vapor cap. For
saturated ethylene dichloride streams at 100°F, taken to a laboratory at
70°F, the condensation results in a 10 percent decrease in the volume;
however, in a 100-liter sample about 40 cc of liquid EDC would be
present. This will dissolve vinyl chloride from the vapor cap, and thus
one would not measure the true vinyl chloride concentration.
A suggested better sampling technique would be to cool the
sample to -4°F and analyze the liquid contents. The total sample
would then be a combination of the liquid condensed and gas
volume which can be accurately measured in the laboratory.
Response: No steam vent analyses are contemplated.
EPA investigated the possibility of water condensation causing
errors in the bag sample vinyl chloride concentration, due to condensation
of vinyl chloride with negative results. Since all bag samples would be
analyzed at room temperature, it is expected that the vinyl chloride
concentrations would be automatically normalized to the corresponding
water_vapor saturation concentration. The bag concentration of vinyl
chloride is finally reported on a dry basis, corrected for that water
vapor concentration.
The importance of the reported effect of condensed ethylene
dichloride on the vinyl chloride concentration is still being investigated,
but no actual case where the suggested situation exists has been found.
However, if such a case does occur, the suggested technique should prove
to be acceptable.
13. VC-27
Comment: The use of a reverse "S" type pi tot tube for flow measurement
as described in Test Method 106 is adequate for highflow rates like
those in the vent scrubber stack; however, for tank vents, vents on
vessels, and other low flows (less than 10 fpm) the "S" type pitot tube
does not give adequate flow measurements.
2-76
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Response: Currently there are no low flow (less than 10 fpm) streams
which are required to be tested. If this problem should arise in the
future, it can be resolved at that time.
14. VC-27
Comment: The isothermal method of operation in Test Method 106
is fine for "air samples" but in analyzing vent streams up to 2 hours
would be required for one analytical run. Analyzing each sample to +_ 5
percent might require 6-8 hours of analysis to get a repeat on one
sample. For several samples taken the same day there would be an
inordinate amount of time for analysis. We would suggest duplicate runs
in a temperature-programmed mode of operation.
Response: With proper care, temperature programming of the gas
chromatograph operation should facilitate analysis, and is not meant to
be precluded by absence of a description in the test method.
15. VC-27
Comment: The daily calibration curves required by Test Method 106
are unnecessary. A calibration curve run once for linearity and one
standard daily check should maintain quality control on the instrument.
Our experience has shown that vinyl chloride factors on a flame detector
are valid for several months.
Response: If Method 106 tests are run on a routine basis, experience
may show that daily calibration is unnecessary; however, for
limited applications, the daily calibration would be advised.
16. VC-27
Comment: The leak-proof rigid containers described in 4.1.5
of Test Method 106 are the size of a 40 gallon drum and would be
extremely difficult and hazardous to move to the top of a vent scrubber,
out of a tank farm, etc., and would pose serious operator problems for
sample-point logistics. Alternative considerations should be reviewed.
Response: Since Method 106 is only rarely used, the on-site disadvantages
of the bag container should not constitute a major problem. For
discussion of replacement of the integrated sample procedure, see
comment VC-14.
17. VC-27
Comment: Only one specific column material is allowed in 4.3.2
of Test Method 106. This should be revised to permit use of any column
which results in adequate resolution and determination of the vinyl
chloride peak.
Response: Chromosorb 102 is the only column which EPA has investigated
to determine possible interferences, etc., for the analysis of vinyl
2-77
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chloride. It is expected that other columns may work equally well but
substantiating data must be provided to EPA before equivalency can'be
determined. The method has been revised to include a secondary column
SomhvinyiechloHdet0 ^^ acetaldeh-yde> if Present, in the sample,'
18. VC-29
Comment: Why is it not possible to use a portable hydrocarbon analyzer
in place of Method 106 in all cases where Method 106 is specified?
Response: Specification of Method 106 implies that a specific
determination of only vinyl chloride (i.e., not to include any other
substance) be made. Method 106 is a reference method, by which
the appropriateness of other methods for specific applications
can be judged.
19. VC-29
Comment: "The use of a heated sample loop and automatic sample
valve (Section 4.3.1) is not necessary since the bag sample is
not heated. A gas tight syringe is adequate for transferring the
sample from the bag to the gas chromatograph."
Response: Because of the relatively small surface area/volume ratio
of the heated sample loop and automatic sample valve, heating
produces favorable results insofar as peak resolution and sharpness
are concerned. Use of an automatic sample valve, as opposed to
a syringe, greatly improves the repeatability of analysis.
20. VC-29
Comment: Equilibrium data for the vinyl chloride-water system.
are available which conflict with the EPA K-value of 5.0 x 10~6
(p. 59552, Column 2). Air Products reports a value of 1 3 x 10
•which is more consistent with a value of 0.9 x 10"5 determined by
Ethyl Corporation the constant in equation 107-5 (2.066 x 10~3)
depends on the K-value for water and should be corrected accordingly.
Response: The K value for a 1 cc water sample of 5.0 x 10"6 was
derived through careful study by B. F. Goodrich. The other K values
apparently are for larger water volumes.
21. VC-29
Comment: Brackets have been omitted from equation 107-5.
Response: Brackets have been added.
22. VC-2
Comment: The last paragraph under 9.2 of Test Method 107 is not
applicable to equation 107-5. Equation 107-5 applies only to water
2-78
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samples, where TS = 0. Reference to 107-5 should be deleted and the
paragraph relocated after equation 107-4.
Response: .This comment is correct; the changes noted have been made.
23. VC-35
Comment: Detailed performance specifications should be given
for the vinyl chloride detector, and should be similar to those
given where monitoring is required in Part 60 (Standards of
Performance for New Sources).
Response: The promulgated standard requires that the monitoring
system consist of a gas chromatograph; or if it is assumed that all
hydrocarbons measured are vinyl chloride, infrared spectrophotometry,
flame ion detection, or an equivalent method may be used. The
standard included this flexibility so that if a plant has purchased a
monitoring system for purposes related to the OSHA standards, it would
not have to purchase a new system to meet the EPA standard. A gas
chromatograph is 100 percent accurate if calibrated properly. EPA has
developed some criteria for judging the adequacy of a plant's calibra-
tion and maintenance schedule for the monitoring system. These will
be included in an enforcement guidelines document.
24. VC-35
Comment: The sampling procedure in paragraph 6.1 of Test Method
106 is not clear. The description of the sampling procedure in paragraph
6.1 and the drawing in Figure 106-1 do not include correct instructions
for purging the sample line prior to sampling. If the instructions are
followed as proposed, erroneous results will be obtained .because the
purged air will be drawn into the sample bag. Paragraphs 4.1.3 and 6.1
and Figure 106-1 should be changed.
Response: The procedure is correct as written. While the sample
line is purged into the bag, the bag is subsequently evacuated
before sampling commences.
25. VC-35
Comments: Four typographical errors are noted.
Response: These corrections have been made.
26. VC-42
Comment: A specialized procedure is described in §61.67(g)(l)(i)
for use in sampling the emissions due to purging of vinyl chloride
from reactors after a batch is completed.
Response: EPA calls this reactor opening emissions and has specified
a method separate from the stack test method for testing these
emissions. See §61.67(g)(5).
2-79
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27. VC-42
ocnt lh §61:67(d) the average of three runs may not be adequate to
represent the emissions. It is recommended that EPA require the source
operator to supply technical evidence that the average of the three
adequately represents the total emission rate for each source tested
Response: Most of the regulations in Parts 60 and 61 require that
three runs be conducted for each test. There is no apparent
reason for making the testing for vinyl chloride different. It is
JM! S^rCS °Perator would "s"PPly technical evidence that the
h 5re? ^nns adequately represents the total emission rate
t !C A I — *- test*d .W1'thout doing additional tests. EPA believes
that a definitive endpoint on the number of runs conducted is necessary.
28. VC-42
Comment: With regard to Test Method 106 we recommend the use of
f •" ,tUb^9 and tedlar bags-to minimize the absorption and
1075A? 1975) by the PlaStl'CS ($ee Analytical Chemistry.
Te-la!I ?ugs are sPecified. Aluminized Mylar bags can also
used, provided that the samples are analyzed within 24 hours of
S2ni!2m°n; * ofuTeflon tubing is monitored through labeling and
replacement for each new set of samples.
29. VC-44
Commentator VC-44 fails to see the need for taking a vinyl
sample at a rate which is proportional to the gas stream flow
-oncentration variation is not necessarilv nrnnnrfinnai tn
mass flow and the sampling can be stopped between batches^if necessary.
Response
to
Use of Method 106 implies that a time averaged sample is
1nstancwhe^ a Proportional sample would no i
conce"tration was proportional
!8 not done proportionally, then the burden
,,+ that proportional sampling was not necessary will lie
vntn those doing the testing.
2-80
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30. VC-50
Comment: Commentator VC-50 has found that on a Chromosorb 102 column
using helium carrier gas, acetaldehyde has the same retention time as
vinyl chloride and vinyl chloride cannot be distinguished from acetaldehyde
unless the effluent from the column is fed into a mass spectrometer. It
is therefore recommended that unless acetaldehyde is positively known to
be absent from the stack gas, a different column be used.
Response: Section 3, "Interferences," of Test Method 106 will be
reworded to include specific precautions regarding acetaldehyde
interference.
2-81
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2.7 Economic Impacts
1. VC-17
Comment: Imposed substitution of other materials for polyvinyl
chloride products may have adverse economic effects.
Response: Substitutes for polyvinyl chloride are not being imposed
upon the industry. Polyvinyl chloride products will still be free to
compete in the marketplace with substitute products on the basis of
price and performance characteristics. It is believed that the price
increase in polyyinyl chloride resins resulting from the standard will
not cause appreciable substitution of other products.
2. VC-22
Comment: The decrease in demand for polyvinyl chloride during 1973-74
stated as 2.4 percent should be 0.4 percent and referred to as a decrease
in consumption, not demand.
Response: The figure'for decrease in consumption of 2.4 percent
was based upon an estimate of 1974 sales. Final 1974 figures now
available indicate that the actual decrease was 0.5 percent. It
is agreed that "consumption" is a better term than "demand".
3. VC-26
Comment: EPA's estimated installed capital cost of $524,000 for
the oxychlorination process incineration is too low. The commentator
estimates the cost to be $2,200,000.
Response: EPA did not estimate the cost of the oxychlorination
incinerator to be $524,000 but rather 524,000 times the volume of
the stream to be incinerated raised to the 0.53 power. At the
model plant volume of approximately 6100 SCFM this results in a
capital estimate of $1,369,000 (Table 7-7, page 7-78). The basic
algorithm that was used for cost estimating purposes was based
upon information submitted by five vinyl chloride producing
2-82
-------
firms and one EPA contractor. The commentator's estimate was one of the
estimates used by EPA to develop the basic algorithm.
4. VC-26
Comment: The description "Allied Chemical/Geismar" used in
Tables 7-24 through 7-32 should be changed to "Allied Chemical/
Baton Rouge". The production capacity attributed to Allied
Chemical in the STAR document is incorrect.
Response: No response necessary.
correction.
5. VC-26
This comment serves as a
Comment: EPA estimates for control costs at the Allied Chemical/
Baton Rouge facility are lower than current company estimates.
Response: The total cost for the Baton Rouge plant is obtained by
adding the costs incurred at the ethylene dichloride plant (Table 7-17)
with the costs incurred at the vinyl chloride plant (Table 7-24). If
this is done the total air pollution control costs are estimated to
amount to $889,000 and total water pollution control costs are estimated
at $1,775,000 for a grand total of $2,664,000 versus the company estimate
of $2,260,000.
6. VC-27 '
Comment: The view that large, integrated petrochemical and chemical
companies would supposedly have access to sufficient capital to
invest in control devices is inappropriate without consideration
of other company projects competing for capital.
Response: Consideration of the capital demands for competing
products has been recognized. The background document states:
" ... firms that own the various ethylene dichloride plants are
generally large, integrated petrochemical and chemical companies that
would supposedly have access to sufficient capital to invest in the
additional control equipment. Whether a firm would actually choose
to invest those funds in control devices, however, cannot be
predicted with any degree of certainty particularly for those firms
that are experiencing post-control decreases in profitability compared
to the pre-control case." (Page 7-27) The intent of this statement
was to point out that even though firms would probably have access
to sufficient capital to invest in control devices they still might
not choose to do so for profitability reasons.
2-83
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7. VC-27, VC-29
Comment: Rates of return, profitability, and pricing parameters are
predicted on TOO percent operating rates rather than a more
realistic 85 percent rate. The economic impact would be dramatically
altered if 85 percent was used.
Response: An operating rate of 100 percent was .arbitrarily selected
due to the difficulty in estimating expected operating rates. The
use of this rate, however, does not alter the economic impact of
the standard. The percent price increase that would be required in
order to recover control costs and maintain pre-control profitability
would be essentially the same whether 100 percent or 85 percent was
used as the basic operating rate.
8. VC-27
Comment: Incineration costs for the model ethylene dichloride-vinyl
chloride facility are understated.
Response: EPA does not believe that costs for the model ethylene
dichloride-vinyl chloride plant are understated. EPA is aware of
the incinerator costs claimed for the commentator's plant and
believes that these costs include items that would not be found in
a typical facility.
9. VC-29
Comment: Production decreases in 1975 caused depression in prices
and profits which reduced the capability of the industry to obtain
capital or raise prices.
Response: Whereas conditions in the polyvinyl chloride industry
were depressed in 1975, a return to more normal conditions is
expected for the industry. Since it is not possible to develop a year-
by-year impact analysis based upon projected industry performance it
must be assumed that normal conditions will prevail in the long run.
10. VC-29
Comment: No adjustments for inflation to 1976 and 1977 conditions
were made in the cost estimates.
Response: All financial information, control costs included, was
adjusted to reflect conditions as of a certain date. The assumption
has been made that product prices will generally rise along with
increases in costs so that profitability will be unaltered over time.
Given this assumption it is unnecessary to adjust costs and revenues
for inflation since their increases essentially cancel each other out.
2-84
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11. VC-29
Comment: The estimate of capital requirements for a carbon
adsorption system in the model suspension process polyvinyl chloride
plant is understated.
Response: The polyvinyl chloride model plant carbon adsorption costs
were based on data obtained from four sources of information: three
polyvinyl chloride companies and one EPA contractor. The installed
costs, when scaled to the model plant volumetric flowrate, ranged from
$140,000 to $545,000. The $333,000 figure was the average of these four
estimates. As this example illustrates, the EPA model plant control,
costs were based on data from diverse sources. They do not necessarily
reflect the situation at any particular polyvinyl chloride plant, where
the costs may be higher or lower for one or more reasons.
12. VC-29
Comment: The capital and operating costs for incineration are under-
stated by a factor of two for polyvinyl chloride plants and a factor
of two to three for ethylene dichloride-vinyl chloride plants.
Response: The costs for incineration at polyvinyl chloride and
ethylene dichloride-vinyl chloride plants have been based on a range of
data. Six information sources were employed: five companies and one
EPA contractor. The installed cost listed industry sources in Table 7-7
resulted from a least-squares analysis of the cost data from these six
sources and is intended to represent average conditions. It is expected
that some facilities would experience lower costs and some would experience
higher costs.
13. VC-29
Comment: The allowance for administrative, selling, research and
development, and interest costs is understated and overstates
the return on investment at a given plant.
Response: Estimated costs for these items were derived after
consultation with a committee composed of industry representatives.
EPA sees no valid basis for altering any of the figures that
were used.
2-85
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14. VC-29, VC-32
Comment: Costs are grossly disproportionate to benefits for
water striooing, evacuation of compressors, double mechanical
seals on pumps, leak detection, and removing vinyl chloride from
reactors before opening:
Response: The standard for vinyl chloride is based on best
available control technology. The term "grossly disproportionate"
was introduced into the supporting documents for the standard
because the term "best available control technology" could be
interpreted indifferent ways and EPA thought it was desirable to
place some limitations on it. The first limitation was that the
control technology must be in useTn one or more plants in the
chemical industry and be generally adaptable for use at the plants
subject to the standard within the time allowed for compliance under
section \\d. Second, costs were considered only when they were
jrojjsTy disproportionate to the emission reduction achieved. Technologies
Xi£ •fP5 c°nsildere* *? not f1t i^o ^s definition of best available
control technology included placing a bubble around a plant to capture
all the emissions from it for control, using multiple incinerators on
a gas stream, and incineration of the emissions from the oxychlorination
f^elt' Theulrea?on for not requiring incineration of the emissions
from the oxychlon nation process are the relatively low emissions
from it compared with the very large expenditure of energy which
would be required to incinerate.
Obviously, there is some judgment involved in interpreting
which costs are "grossly disproportionate." In EPA's judgment
the cost of controls mentioned by.the commentator are not in the
same category with the oxychlorination process. Although the
commentator may view these controls as not being cost-effective,
in hPA s judgment the costs are not grossly disproportionate.
Altougn t"*: economic impact study included in the SSEIS, Vol. I
°SI"er^t1veneSS' 1ts pr1mary PurP°se was to inform EPA
nrfrfSS ? K35 affordable and> ^ so, what the impact would be,
3 *d -S n°! b!sed on costs- The cost data was developed to
Art!e th* T*? °f the standard- ^en under section 111 of the
Act, where standards are to be based on "best demonstrated control
the s?]nH^HC°nS1^nH9K?°StSlu; the stan
-------
discharges and reactor opening is .31 and for water stripping is .80.
Evacuation of compressors, double mechanical seals or pumps-, and leak
detection are included in the cost-effectiveness ratios for fugitive
emissions.
1-5. 'V029
Comment: On Table 7-40, Tenneco/Flamington:, Tenneeo/Pasadena, and
Union Carbide plants were .omitted.
Response: The comment is correct.
1.6. VC-29
Comment: On Table 7-T5, the total annual i zed cost should fee $773,000
ead of $793, 000.
Response: The correct number is $793,000. However » the figure of
$407,000 shown on Table 7-15 should be $427,000.
17. VC-32
Comment: The number of plant shutdowns has not been accurately
estimated.
Response: The number of plant shutdowns was inaccurately estimated,
in that three out of four plants EPA forecasted would close have
since, told EPA they will not close. The fourth plant ho longer produces
polyvinyl chloride. Plant closures attributable to other regulations,
if any, are not considered since they are not believed to be a direct
consequence of the proposed EPA regulation, it would appear that the
immediate cause of the closing of the Uni royal plant is the OSMA regula-
tion, although anticipation of the EPA regulation may have influenced
the decision.
18. VC-32
Comment: The economic analysis is simplistic.
Response: The major thrust of the economic analysis; is to4
determine the impact upon, industry gr-owthi,, prices, awd p'tartf!
closures. It is believed that these issues, are treated iii a*
full and complete manner.
19, VC-34
Comment: EPA cost estimates are low.
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Response: EPA cost estimates were based upon estimates provided
by control equipment vendors and by polyvinyl chloride industry repre-
sentatives. As might be expected, estimates of control costs varied.
EPA believes that its estimates reflect average costs that might be
incurred at a typical facility. It is expected that individual plants
will have control costs that vary from the EPA estimate on both sides.
20. VC-34
Comment: Polyvinyl chloride plant profitability in Table 7-5
is overstated.
Response: The prices shown in Table 7-5 were published prices.
Prices used in succeeding profitability calculations were based
upon consultation with industry representatives.
21. VC-34
Comment: Annualized capital charges do not include any profitability
factors.
Response: Annualized capital charges, by definition, exclude
profitability factors. An analysis of profitability impacts is
carried out in the economic analysis.
22. VC-34
Comment: The bases for the direct operating costs for control
alternatives is questionable.
Response: The various items included in the direct operating
costs were discussed in Chapter 7, on page 7-9.
The unit prices used on computing these various items are as
follows:
Fuel:
Electric Power:
Steam:
Inert Gas:
Labor:
Cooling Water:
Process Water:
Caustic Soda:
23. VC-34
$2.Do/million BTU
$0.03/kw-hr
$3.00/thousand pounds
$.21/100 SCF
$6/man-hr.
'i.lO/thousand gallons
$.25/thousand gallons
$0.35/lb
Comment: The process scope for estimating investment costs for
control alternatives is questionable.
2-88
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Examples are: (1) rubber-lined carbon-steel slurry tanks to replace
stainless-steel vessels, (2) reactor opening control does not include
tanks, pumps, and distribution lines for water purge or headers for
relief valve vents, and (3) no scope description for improved stripping.
Response:
follows:
The process scope for estimating investment costs is as
1. Slurry Blend Tanks
As is stated on page 7-14 of the Standard Support and Environmental
Impact Statement, the existing slurry blend tanks in the model plant
are insufficient to withstand the pressure associated with venting to
an incinerator. Therefore, they would probably need to be replaced.
The costs in the document were based on the following assumptions:
o
Each blend tank had a capacity of 24,000 gallons (3,342 ft ).'
Two tanks were installed in each reactor line.
The cost of removing an existing tank was offset by its
salvage value.
The tank diameter equalled the height (16.2 feet).
The tank design pressure rating was 50 PSI gauge.
Tanks were fabricated of a carbon steel, lined with 1/4 inch
rubber.
Costs were obtained from Guthrie's "Process Plant Estimating
Evaluation and Control," 1974 edition, p. 151.
2. Reactor Opening Controls
As tables 7-8 and 7-9 indicate, costs for reactor purge
water systems have been developed for controlling the relief valve
discharge and reactor opening emission points. Each of these
systems includes a storage tank for the purge water, a header system
and pumps to deliver the water to the reactors.
The capital costs were obtained from two sources, both of which
were polyvinyl chloride plants using these systems at the time. The
costs - $102,000 and $310,000 were averaged to obtain the $206,000
figure for the model suspension plant, the dispersion plant cost
($78,000) was calculated by scaling from the suspension plant reactor
capacity (90,000 gallons) to the dispersion plant capacity (18,000
gallons), using a 0.6 factor.
Although the costs of a header system for relief valve vents was
not included under reactor opening controls, it was accounted for under
fugitive controls (see tables 7-11 through 7-14). The cost of this
2-89
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collection header system varied substantially according to each
plants' process configuration. Based on data from four polyvinyl
chloride plants, the installed system cost ranged from $15,000 to
$229,000. (Process capacity had no recognizable effect on the
costs). The average of these numbers ($84,200) was used for all
form model plant costs.
3. Improved Stripping
The costs for improved stripping varied considerably among the
sources from which data were obtained. For stripping in suspension
plants, data were submitted on four plants, ranging in capacity
from 70 to 250 million pounds/year. The installed costs ran from
$195,000 to $2,085,000.
These costs were plotted against capacity on logarithmic
paper and the function listed in Table 7-6 resulted.
The same approach was used for dispersion improved stripping.
Here data from four plants (ranging from 16 to 60 million pounds/
year in capacity) were used.
For bulk plant stripping, cost data from one plant (with a
capacity of 160 million pounds/year) were scaled to the model plant
capacity, 100 million pounds/year, using a scaling factor of 0.53
(This factor was taken from the suspension and dispersion plant cost
functions).
The various improved stripping systems used in deriving the
cost functions differed in scope, simply because the plants in which
they were installed had diverse process configurations. However, a
typical system included: stainless steel stripping vessels with
agitators, condensers, and vacuum pumps, plus all the required
instrumentation, piping, etc.
The bases for direct operating costs were as follows:
Where itemizations were available, the following unit values were
used to complete direct operating costs:
2-90
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Item
I. Operating Labor
II. Utilities:
1. Electric Power
2. Fuel (Natural
3. Process Water
4. Cooling Water
5. Steam
III. Operating Materials
1. Sodi urn hydroxi de
2. Nitrogen
IV. Maintenance
1. Incineration
2. Improved Stripping
3. Carbon Adsorption
4. Water Stripping
5. Automatic Short-Stopping
6. Automatic Short-Stopping
7. Reactor Purge Water System
24. VC-40
Unit Value
$6/man-hr
$0.03 kilowatt-hr
$2.00/million BTU
$0.25/thousand gallons
$Q.10/thousand gallons
$3.OO/thousand pounds
$0.35/pound
$0.21/hundred cubic feet
5% of Installed
15% of Installed
3% of Installed
5% of Installed
5% of Installed
10% of Installed
6<£ of Installed
Cost/Year
Cost/Year
Cost/Year
Cost/Year
Cost/Year
Cost/Year
Cost/Year
Comment: The economic impact of the regulation has been underestimated.
Response: A detailed company-by-company study was beyond the scope of
the analysis. EPA believes that the estimation of economic impact is
satisfactory.
25. VC-47
The projected capital cost of meeting all the emission
is $198 million. Of this total, $183 million falls on polyvinyl
on ethylene dichloride-vinyl
(including operating and maintenance)
of which $58 million would be
Comment:
standards
chloride plants and $15 million falls
chloride plants. The annualized costs
are expected to be about $70 million,
borne initially by polyvinyl chloride plants and $12 million by ethylene
dichloride-vinyl chloride plants. In addition, the fugitive emission
standards would involve another $37 million of capital costs and $25
million annualized costs.
Response: The statement is incorrect. The cost of fugitive emission
controls is included in the capital cost estimate of $198 million and
the annualized cost estimate of $70 million.
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26. VC-47
Comment: In reading through the proposed standard, there seems to
be some question as to whether or not a spare reactor can be used as
a gasholder or whether a separate gasholder is required. If, in fact,
there is some ambiguity regarding this point, it would be worthwhile
for the EPA to complete some further economic analysis before the
issue is resolved. If a plant already had a spare reactor, the costs
incurred to install a separate gasholder would have little benefit.
Response: EPA is concerned only that a vessel for holding vinyl
chloride be provided. The vessel can be either a spare reactor or
a separate gasholder. The economic analysis took a conservative
approach and included the cost of a separately purchased gasholder.
27. VC-47
Comment: An economic analysis of the trade-offs between emission
risks and prevention costs for control of relief valve discharges
at ethylene dichloride-vinyl chloride plants should have been undertaken.
These discharges occur infrequently at ethylene dichloride-vinyl chloride
plants, as opposed to polyvinyl chloride plants. Based on information
received by the Council on Wage and Price Stability, this requirement
could involve costs as much as $2 million depending on the size of the
plant and the distances involved.
If it is assumed that only one of the 17 ethylene dichloride-vinyl
chloride plants will incur about $2 million to vent relief valves,
$2 million in capital outlay could be saved in addition to any operating
and maintenance costs that might be involved. Consequently, EPA's
analysis should have considered this alternative.
Response: EPA agrees that relief valve discharges from ethylene
dichloride-vinyl chloride plants occur relatively infrequently
compared with polyvinyl chloride plants. The commentator did not
provide EPA with the basis for the $2 million estimate; i.e., the
control technology which would cost $2 million is not discussed.
This makes it difficult to evaluate the comment. The reason for
assuming that only one plant would incur the $2 million cost
is not clear. In talking with industry representatives, it
appears that the types of controls which would be installed to
prevent discharged from these relief valves would consist of
installing additional alarms to warn an operator of upset conditions,
tying thermal relief valves into process lines, and avoiding operator
negligence such as overfilling storage spheres.
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28. VC-34, VC-47
Comment: The projected costs of the standards do not incorporate
any estimates of the costs associated with the research and development
of control technology, lost production from down-time during control
equipment installation, and losses from startup. It seems that EPA should
have incorporated some estimates of these costs if the full impacts
of the standard are to be identified a.nd analyzed.
Response: The comment is correct in that research and development of
control technology would add some additional costs to meeting the
standard. These costs would vary considerable from plant to plant
and are difficult to estimate. Losses from down-time during control
equipment installation and from startup would not appear to add
significantly to costs because polyvinyl chloride production is a
batch process and it is not unusual for ethylene dichloride and vinyl
chloride plants to be shut down for maintenance.
29. VC-34
Comment: The economic analysis fails to consider duplicate control
systems needed to operate at 100 percent service factor.
Response: Costs for duplicate control equipment were not included
since the control systems were designed to operate continuously with
only routine maintenance. It was assumed that the maintenance would
be performed during normal plant maintenance shut-downs.
30. Proceedings from the Public Hearing, Presentation by
Barry Castleman, p. 9.
Comment: Some polyvinyl chloride substitutes must be available
for those uses listed by EPA as having no substitutes.
Response: EPA attempted to list those materials that the industry
believes to be acceptable substitutes for polyvinyl chloride resins.
It is agreed that some substitutes would probably exist for all
polyvinyl chloride uses, but the question of acceptability in
individual applications would have to be evaluated closely.
31. Proceedings from the Public Hearing, Presentation by
Barry Castleman, p. 9.
Comment: The cost of vinyl chloride emissions in terms of worker
health and community health and safety impacts has not been
evaluated.
Response: It was beyond the scope of the analysis to attempt
to quantify in economic terms the cost of vinyl chloride emissions
to the general public.
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2.8 Environmental Impacts
1. VC-21, VC-22, VC-29
Comment: "The discussion of potential adverse environmental impacts
on page 1-24, 1-27, and 1-28 of the SSEIS, Vol. I regarding
increased water consumption seems to be overstated. EPA expects
increased water consumption from the use of such control systems as a
reactor water purge system, improved stripping, waste water stripping,
and carbon adsorption. We believe that there will be little, if any,
increased water consumption and certainly nothing approaching the 6-38
percent range as noted on page 1-28 and as detailed in Table 6-13 on
page 6-42.
"The reactor water purge control technique, according to
Table 6-13, clearly results in the greatest water consumption. It
should be noted, however, that only a small percentage of the polyvinyl
chloride industry intends to utilize the reactor water purge control
method. Also, there is no technical reason that water used for reactor
purging cannot be used over and over again in a completely closed cycle.
Obviously, water used in this type of system would have to be stripped
of vinyl chloride content prior to discharge. Recycling of such water
would minimize stripping requirements thereby conserving energy and
would also minimize the use of our natural resource (water). We believe
the numbers presented for reactor water purging are in error.
"The second noted source of increased water consumption as a
result of applying the necessary controls is that noted for
improved stripping. We question the quantities listed in
Table 6-13. Steam requirements of 1,500-2,000 kg of steam per
10,000 kg of product are stated on page 6-5 for improved stripping.
Using the highest amount stated (2,000) and calculating the steam
requirements for a model 150 million pound per year plant as shown
in Table 6-13, an increased water consumption of 3.6 million gallons/
year is determined as compared to the quantity of 7 million
gallons/year shown in Table 6-13. Similarly, other numbers presented
in Table 6-13 for improved stripping are in error. As noted on
pages 6-5, primary stripping, which is already used by most plants,
required 2,000-4,000 kg of steam per 10,000 kg of product and
improved stripping will require an additional 1,500-2,000 kg of
steam per 10,000 kg of product. While these facts may be correct
for some plants, they are not correct for the industry as a whole.
"Improved continuous stripping technology is not applicable
to dispersion resins due to the extreme differences in stability
of dispersion resins versus suspension resins. Batch stripping
will continue to be employed for dispersion resins. Nevertheless,
the steam quantities given on page 6-5 are greater than that
2-94
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required for stripping dispersion resins. Moreover, recipe water
and steam stripping water do not discharge to a sewer, but rather
are emitted to the atmosphere in the drying operation. Therefore,
there is no increased waste water from improved dispersion resin
stripping.
"For improved stripping of both suspension and dispersion
resins, the quantity of steam sparged into the slurry which would
result in increased water consumption is less than the 3,000-4,000 kg
of steam per 10,000 kg of product stated on page 6-5. We conclude
there will be no increased water consumption due to improved
stripping, and no adverse environmental impact.
• "The quantity of increased water consumption, as shown in
Table 6-13, for water stripping is also questionable. The basis
for such number is not given. It is technically possible to strip
vinyl from these waste water sources by recycling such waste water
sources to slurry stripping systems. By doing so, the amount of
additional steam required is negligible.
"Increased water consumption data given for carbon adsorption
is also questionable. First, this Table assumes carbon technology
will be utilized across-the-board for the industry. Many producers
certainly do not intend to use carbon adsorption. Additionally,
even if carbon adsorption is used, regeneration with hot nitrogen
is technically possible as noted on page 4-61. Obviously, if hot
nitrogen is used, there would be no increased water consumption.
"Considering all other factors as noted above, it is questionable
whether there would be any increased water consumption as a
result of compliance With the proposed standard. Thus, it seems that
EPA should make a more realistic analysis of the situation than
it presently has done. Additionally, the percentage increase of
water consumption as noted is meaningless in itself, particularly
when based on the average of the range of numbers as shown in
Footnote 1 of Table 6-13. The average of this range is extremely
misleading and unrepresentative of industry operations for certain
type of plants. When considering the range of base water consumption,
the percentage increase is less than significant."
Response: Since there is no regulatory limit on the amount of
water a plant can consume, EPA calculated the water consumption
impact assuming that the control systems using water would be
used and that there would be no recycling. It is gratifying to
EPA to know that recycling will be used and that the water consumption
impact will be negligible.
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2. VC-29
Comment: The concern for hydrogen chloride emissions is overstated
Incineration will be used only to a small extent in vinyl chloride
manufacture and to a lesser degree in the polyvinyl chloride
industry because of economics.
1s Pleased 1f the hydrogen chloride impact is overstated.
vol. I stated that incineration would be used only to
a very limited extent in the polyvinyl chloride industry. The
commentator did not name the types of control which would be used
in the ethylene dichloride-vinyl chloride industry or explain the
reasons for not using incineration to a large extent. The
hydrogen chloride impact was calculated for an individual model plant.
J-or those plants which do use incineration to control ethylene dichloride
purification and vinyl chloride formation and purification, the commentator
did not explain why the hydrogen chloride impact is overstated.
3. VC-29
Comment: The impact on solid waste stated for a carbon bed is
conjectural. Not enough is known of bed life to permit an estimate,
and the one to three years presented has no basis. It cannot be
regenerated if contaminated by polymers, since polyvinyl chloride
is less combustible than carbon.
Response: Page 1-29 of the SSEIS, Vol. I states that "since there has
been very limited experience with carbon adsorption in the ethylene
di chloride- vinyl chloride or polyvinyl chloride industries, it is not
known for certain at this time what the carbon bed-life would be or
whether the damaged carbon could be regenerated." The 1 to 3 year
estimate was given to EPA by a vendor of carbon adsorbers based on
experience with other substances, but is acknowledged to be conjectural.
It is based on the only information available at the time.
4. VC-22
Comment: On page 6-5, it is stated that "the amount of vinyl chloride
released into the inprocess wastewater is expected to be proportional
to the amount of steam used, and thus would be increased by improved
stripping." This statement is incorrect. In a stipping operation,
the vinyl chloride removed from the resin is not transferred to the
water but rather actually passes overhead as a gas with the steam.
The steam is condensed and recycled back to the stripping operation
2P96
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Response: Since there is no requirement to reuse the steam, it
was assumed that no recycling is involved. EPA is pleased that
at least the company represented by the commentator recycles the
steam.
5. VC-23, VC-35
Comment: EPA should require recycling of sludge from polyvinyl
chloride plants if possible. The air emissions from sludge
disposal sites have been subjected to preliminary investigation
by EPA. Vinyl chloride levels at landfills were as high as 1.9 ppm,
and in a residential area near one landfill the air contained 0.4 ppm.
This exposure, because it is continuous, actually exceeds that
permitted in the workplace (1 ppm, 8-hour exposure, 40 hours per
week).
Response: The data referred to were obtained during a study done
by Battelle for EPA which is entitled "A Preliminary Examination
of Vinyl Chloride Emissions from Polymerization Sludges During
Handling and Land Disposal" and is dated February 13, 1976. The
results obtained were relatively high but it should be noted
that they are instantaneous measurements. The 1.90 ppm figure cited
by the commentator was measured only about 5 cm from the discharge
stream during the discharge of fluid sludge to the landfill. The
next highest measured value in the landfill area was 1.10 ppm. The
study referred to was a preliminary study only. EPA's Office of
Solid Waste Management Programs is planning to conduct a more
detailed follow-up study to determine the extent of the problem.
At the conclusion of that study it will be determined whether a
regulation is needed, and if so, what type of control should be
required.
There are two sources of the solid waste; (1) resin that
cannot be marketed because it does not meet certain specifications,
and (2) sludge removed from centrifuges and placed in ponds to
separate out additional water. The vinyl chloride in sludge is primarily
due to the vinyl chloride contained in polyvinyl chloride that collected
in the centrifuge. Improved stripping required by the standard will
reduce the vinyl chloride .content of the polyvinyl chloride resin, and
thus also of the sludge.
On a trip to a polyvinyl chloride plant, the plant personnel stated
that much of the "off-spec" resin is sold or recycled by blending it in
with other batches. The plant had just recently begun to also recycle
the polyvinyl chloride sludge from the settling ponds. Another company
has recycled sludge when the market demand for polyvinyl chloride has
been high.
2-97
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6. VC-23
Comment: The standard should be revised to require scrubber
control of hydrogen chloride emitted from incinerators used to
control vinyl chloride.
Response: In the preamble to the proposed standard, EPA indicated
that it has plans to further evaluate the hydrogen chloride problem.
Before establishing standards for -a pollutant, EPA does a study which
looks at the health effects and sources of the pollutant and determines
whether standards should be set, and if so, under the authority of
which section of the Clean Air Act. The National Academy of Sciences
(NAS) has recently prepared for EPA a document which includes information
on the health effects of hydrogen chloride. There are several
sources of hydrogen chloride emissions. In fact, in ethylene dichloride-
vinyl chloride plants, an incinerator used to control vinyl chloride
is only one of the sources of hydrogen chloride. Since hydrogen chloride
is a raw material in the manufacture of ethylene dichloride and a
by-product in the manufacture of vinyl chloride, it is emitted from
process equipment.
7. VC-46
Comment: Pages 6-33 of the SSEIS, Vol. I discusses allowable emissions
in terms of pounds of kilograms of vinyl chloride per hour, rlo reference
is made, however, to how the allowable emissions compare with the
proposed standard.
Response: Pounds and kilograms are both a measure of mass. Pounds are
in English units and kilograms are in metric units. In its documents
EPA usually gives data in terms of metric units with the English units
in parenthesis.
The standard, most of which is expressed in terms of
concentration units, is related to the mass units in the following
manner. EPA selected an average plant size. The production rate of the
plant and the air flow rates from the equipment in the plant are known.
With this information, it is possible to calculate the mass emission
rates that would be emitted from this certain size facility when the
standard is in effect.
2-98
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8. VC-46
Comment: Pages 6-33 through 6-39 of the SSEIS, Vol. I compare the
concentrations of hydrogen chloride in the vicinity of plants incinerating
vinyl chloride with standards for hydrogen chloride in other countries.
It is stated that EPA does not have a standard for exposure to hydrogen
chloride and thereby lacks a yardstick for comparative measurement.
Without further expansion, reference to ambient standards allowed in
other countries should be omitted and justification should be presented
for including a discussion over the ambient standards of 5 ppm which
have already been established.
Response: In presenting information on environmental impacts,
EPA believes that it is meaningless to report a long list of
numbers without relating them to something. It would be helpful
to compare them to an EPA standard. If one does not exist, it
seems reasonable to compare them to standards established in other
countries. These standards are based on health effects data. The
5 ppm standard referred to is for occupational exposure. All
of the other standards discussed are below 5 ppm.
9. VC-46
Comment: Page 50 of the SSEIS, Vol. I discusses the caustic which would
be required to neutralize the HC1 collected in scrubbers. The fate and
cost for disposal of the large amount of brine which would be released
after neutralizing the HC1 should be discussed.
Response: Neutralization of the HC1 would result in sodium chloride
being released into wastewaters. Since EPA has not deemed it
necessary to require control of dissolved solids, there would be
no additional cost associated with disposal of the sodium chloride.
As discussed in the SSEIS, Vol. I, the amount of HC1 that would have to
be neutralized would be considerably reduced by reclaiming the HC1. HC1
is a raw material used at ethylene dichloride-vinyl chloride plants.
10. VC-46
Comment: On page 6-59 of the SSEIS, Vol. I reference is made that
plants could possibly reduce energy impact because they are typically
located in large petrochemical complexes. The rationale for this
statement should be clearly stated. Proximity to large petrochemical
complexes will afford availability., but will not reduce the energy
required.
Response: Incineration of hydrocarbons produces heat. The
heat can be used in other processes in the plant. This provides
an energy savings because otherwise the heat would have to be
generated.
2-99
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1 . VC-46
Comment: On page 6-59 of the SSEIS, Vol. I, the statement Is 'made that
AlSSIaS'irSnT fP01^] chloride dispersion plants to attain the
Alternate II control level would be increased by a factor of ten over
the energy consumption of plants attaining the Alternate I control
level. Considering that this .alternate would accomplish only a four
percent reduction in emissions of vinyl chloride, some reference
fS i be ™de *? s"ow how much vinyl chloride reduction would be
equivalent to a ten- fold increase in energy to accomplish this
decrease.
hptonfli I-"1" ?6rc!nt diffei"ence in the emission reductions
between Alternative I and II is for ethyl ene di chloride/vinyl
chlori deviants. For polyvinyl chloride dispersion plants
Alternative I reduces emissions by 52 percent and Alternative II
reduces emissions by 95 percent. (See Table 6-2 on page 6-9)
2-100
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2.9 Process and Control Technology (Chapters 3 and 4 of
Volume I of the Standard Support and Environmental Impact
Statement).
' 1. VC-26
Comment: Furnace tubes, in the vinyl chloride conversion from
ethylene dichloride, are not packed with charcoal or pumice as
reported in the SSEIS, but are empty.
Response: EPA's statement was based on a draft document which is
reference 6 in chapter 3. EPA now concurs.
2. VC-22
Comment: Vinyl chloride is a liquid below 7°F. It could not
"float" on a pond of water as written on page 4-52 of the
SSEIS.
Response: EPA concurs. The point was that the residual vinyl
chloride monomer will be evaporated from the ponds, not staying
in the water.
3. VC-22
Comment: Not all pressure rises can be detected by instrumentation
in time to avert over-pressure conditions as stated on page 4-30
of the SSEIS.
Response: Change to "In most cases, potential problems can be
quickly detected by instrumenting each reactor with temperature or
pressure alarms to alert the operator to upset conditions."
4. VC-22
Comment: Gas holders cannot practically hold the vinyl chloride
contained in an entire reactor batch if the reactor is large.
(See p. 4-30 of SSEIS). .
Response: It is technically feasible to construct a gas holder
to hold the contents of the entire batch of a large reactor. At
least one new plant is set up to discharge one reactor batch to
another reactor and thus the second reactor is a "gas holder."
5. VC-22
Comment: The calculation on p. 4-22 of the SSEIS, Vol. I is in
error in using tapped bulk density of polyvinyl chloride instead
of true density (87 Ibs/cu ft).
Response: EPA concurs with the correction. The true density
was not available to EPA at the time of the calculation.
2-101
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6. VC-22
Comment: The statement on page 4-76 "... each of these techniques
can reduce the vinyl chloride content of the case being treated
to less than 10 ppm," should be qualified by noting that use of
HoL + lq!!eS (adsorPtion, absorption, and incineration) has not been
demonstrated under production conditions for all sources.
Response: EPA agrees that thdse techniques have not been used
under production ^facili ties for all sources. However, it is believed
that these techniques can be designed to meet the emission limit
even though different production conditions exist at different plants.
7. VC-22 ~
Comment: Table 4-3, page 4-81 shows achievable emission levels for
certain controls on certain sources to be zero emissions. This
figure is inconsistent with reported performance of control devices
(Also same comment for Table 4-4, p. 4-83). '
Response: Where the emission factors were less than 0.001 kq/100 kq
they were considered zero.
8. VC-33
Comment: Double mechanical seals are fine for vertical vessels
but for horizontal vessels, a grease stuffing box is safer and
more practicable.
Response: EPA concurs that the two methods are equivalent.
9. VC-34, Attachement 1, page 1
as reported 1n Tables 3~6 and 3-7 do not
Response: In the spring of 1974, (the baseline for all of EPA's
emission data) not all strippers were vented to a recovery unit.
EPA averaged the emissions from these plants over the entire industry
for the factors given on Tables 3-6 and 3-7.
10. VC-29
Comment: A more reasonable polymerization cycle time for suspension
polymerization than the 6 hours given in the SSEIS is 10-12
hours /batch.
Response: EPA agrees.
2-102
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11. VC-29
Comment: The saturation point for vinyl chloride monomer in
water is 1100 ppm at standard conditions, thus it is impossible to have
concentrations of 2000 ppm as reported on page 3-15.
Response: The 2000 ppm figure was given to EPA by the B. F. Goodrich
Chemical Company in a visit to their Henry, Illinois, plant on
April 8, 1975. The estimate was based on their own tests of
inprocess waste water from the plant. EPA feels that the condition
is possible under non-equilibrium conditions with impure water streams.
12. VC-29
Comment: The origin of the data in Tables 3.6-3.9 is not
reported, nor is the specific process for Table 3.7 identified.
Response: Tables 3.6 through 3.9 were, developed from data submitted
by vinyl chloride monomer and polyvinyl chloride producers in
response to a May 31, 1974, section 114 request by Mr. Don Goodwin.
Table 3.7 deals with both dispersion and latex resins.
13. VC-29
Comment: In bulk plants, the popo reactor may be cleaned after each
batch and must be opened to transfer the product. This is clearer than
the statemenFgiven in section 3.2.2.3 of the SSEIS, Vol. I. New
data is available on emissions from bulk plants to update Table 3.8 of
the document.
'Response: EPA agrees with the first comment. While emission
factors have changed in bulk plants, EPA does not plan to update
Table 3 8. The factors in that table are based on data supplied
to EPA in May 1974, the base date for the uncontrolled plant.
14. VC-29
Comment: The estimates in Table 3-9 for solution resins are
incorrect since reactor opening loss and dryer loss are both
non-existent.
Response: On June 26, 1974, the sole manufacturer of this
type of product reported a dryer loss. The company also reported
a precipitation tank loss equivalent to the reactor opening loss.
The category in Table 3-9, "reactor opening loss should be
considered "precipitation tank loss."
15. VC-29
Comment: According to Chapter 4, carbon adsorption is not
applicable to streams with low vinyl chloride monomer concentration,
high in water and particulate and composed mainly of air. Untested
2-103
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technology, such as this, should not be considered in the document.
The discussion of carbon adsorption and ion exchange resins is irrelevant
to the study.
Response: Chapter 4 never said that carbon adsorption was inapplicable
to any particular source. The document states that carbon adsorption
is more practical for some than for others. There are no sources
in ethylene dichloride-vinyl chloride or polyvinyl chloride plants
where carbon adsorption is technically impossible to apply. Carbon
adsorption is used commercially on similar streams.
16. VC-29
Comment: Spray towers, spray chambers and venturi scrubbers
are_inefficient devices as solvent adsorbers. Ten ppm would
be impossible. Scrubbing vinyl chloride monomer gases to 10
ppm using water or aqueous solutions of sodium carbonate or
sodium hydroxide is not possible using present technology. Use
of a lower volatility solvent is not feasible because of problems
in separating vinyl chloride monomer and the solvent.
Response: EPA did not claim, in Chapter 4, that any of the
described solvent absorbers could achieve 10 ppm. The chapter
pointed out that a number of factors affect control efficiency
on these devices including temperature, concentration, and design.
17. VC-29
Comment: The figures used in pages 4-34 and 4-35 of the
Standard Support and Environmental Impact Statement are incorrect. The
references should be Table 3-6, not 3-5 and the reactor opening loss is
0.14 kg/100 kg/not 0.46.
Response: The table number is incorrect. The figure for reactor
opening loss includes the figure in Table 3-6 for opening of
0.14 and stripper loss of 0.32.
18. VC-29
Comment: The suggestion on page 4-46 that equipment could
be fitted with high pressure spray heads is incorrect for the
majority of existing .reactors which do not have nozzles of
adequate size to permit passage of the spray head.
Response: EPA points out again that not all of the discussed
control procedures are applicable to all sources.
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19. VC-29
Comment: The discussion of polyvinyl chloride inprocess waste
water should note that the suspension resin process is involved.
All data given is based on the suspension process.
Response: EPA concurs.
20. VC-17
Comment: The preamble and the document suggest that bulk
process reactors be purged with nitrogen gas and vacuum. The
writer suggests that steam has been shown to be effective in
some cases.
Response: EPA concurs.
21. VC-21
Comment: "EPA does not define dispersion, latex, and emulsion
resins well. Clarity is needed in the process description. The
following is offered: "The dispersion polymerization is discussed
as though these are basically emulsion type polymerizations.
Although the emulsion process is used, or can be used, to produce some
dispersion resins it is not the principle method used. The comments
describing the equipment are in error. The process is similar to
the suspension process only in that monomer, water and catalyst
are used in the polymerization. The difference is not that more
soap is added to the slurry to stabilize the monomer droplets and
form agglomerates. Suspension resin (p. 3-11) uses vinyl chloride
monomer, water, catalyst and suspending agents, not soap. Dispersion
resins use a dispersing technique which does not relate to suspending
techniques as the article implies. If the emulsion process is used,
it uses an emulsifying technique which again is quite different."
"The particle size of the suspension resin after polymerizing
and after drying is essentially identical. The particle size of
the dispersion or emulsion resin after polymerizing is sub-microscopic.
The spray dryer used to dry dispersion resins produces a particle
size wuich depends on the type of spray.
"Latex resins are not produced by the dispersion process; they
are produced by the emulsion process, quite different, technically.
More soap may be used but not during the polymerization. In some
instances soap may not be added after polymerization which results
in an unstable condition and leads to difficulty in stripping."
Response: EPA agrees that perhaps more clarity is needed in
defining the various resins in the process description. The Agency
points out, however, that these distinctions do not affect the
proposed standard.
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22. VC-21
Comment: On page 3-13, polymerization pressure is stated to be
5.1-5.8 atmospheres while on page 4-30, polymer pressure is
stated to be 6.1-7.8 atmospheres. The latter figure is more
nearly correct.
Response: EPA agrees.
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2.10 Comments on Quantitative Risk Assessment for Community
Exposure to Vinyl Chloride
1. VC-22, VC-27, VC-29, VC-32, VC-34
Comment: The risk assessment should have been based on the log-
probit model, rather than the linear no-threshold model.
Response: A number of arguments were made by industry in support
of this comment; they are discussed in turn.
First, it was argued that the risk assessment document was biased
in favor of the linear model. It was the intention of the authors that
the two extrapolation methods should have equal status; any impression
to the contrary was inadvertant. Both methods are supported in the
scientific literature, and both are equally lacking in empirical
confirmation. It is true that the log-probit model results were
shown as a range determined from a sensitivity analysis of the
linear model results. This was done because it is computationally
much more difficult to get a single number for the log-probit model,
and the value of the number for the decision maker did not appear
commensurate with the amount of work required to get it. Because
the log-probit curve is non-linear and falls off very rapidly with
dose, the results will be determined by the groups with the highest
exposure and it is not valid mathematically to apply it to average
data for large groups (as several industry comments have done). It
would be necessary to perform a separate calculation for each
community, direction, and distance category (over 2,500 combinations),
and even this might not be sufficiently fine-grained. The only payoff
of this massive amount of work would be to know just where in the
range of, for example, 0.1 to 1 cases/year the log-probit results
fall. Knowing this would not greatly help the Administrator in
making a responsible decision.
Second, it was argued that the log-probit model better fitted
the actual animal data and should therefore be the basis for
extrapolation. While it is true that the deviations of the log-
probit model from the actual data were somewhat smaller than for
the linear model, the differences are not large enough to have any
statistical significance. And even if they were statistically significant,
that would not necessarily be a controlling consideration. The choice
of a preferred extrapolation method should depend on one's view of
the mechanisms of carcinogenesis and on the degree of conservatism
one feels is appropriate. Neither of these is greatly affected
by small differences in .the fit of the two curves at high doses. And
even if it is believed that variations in susceptibility are the main
factor affecting dose-response, no information is available on
the tails of the distribution.
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Third, it was argued that the "log-probit method is more generally
accepted or that "Nature seems to operate in the normal distribution
(log-probit) mode." In fact, it seems more accurate to say that
both approaches have support in the literature; support for a linear
model is found, for example, in Hoel, et al., "Estimation of Risks
of Irreversible, Delayed Toxicity," J. Toxicology & Environmental Health.
Vol. 1, No. 1 (1975) and FDA Advisory Committee, "Panel on Carcinogenesis
Report, Toxicology & Applied Pharmacology, Vol. 20, pp. 419-38 (1971).
Support for the linear model and its variants is generally based on
the notion that cancer occurs as the result of random events at the
cellular level.
Finally, it was argued that animal data on the metabolism of
vinyl chloride shows that the log-probit model is more appropriate.
While there are some difficulties in interpreting these data (which are
discussed elsewhere in these comments), this argument may well turn
out to be correct. The current state of knowledge is not sufficient,
however, to prove it.
In summary, it still appears justifiable to present the results
of both models and to allow the decision maker to decide what
weight to give to each.
3. VC-29, VC-34
Comment: Recent animal studies indicating a change in the pathways
for vinyl chloride metabolism at low doses suggest that a threshold
dose rate exists below which cancer is not expected to occur.
Response: The metabolic studies do not measure tumor incidence,
which is the end result of many biochemical reactions and cellular
changes which are not well understood. Therefore, they are not
directly relevant to the quantitative relationship between cancer
incidence and dose rates. It is not known whether the malignancy
results from the parent compound, one of its many possible metabolities,
or from some consequence of the reactions which metabolize the
compound. Since each of these possibilities is expected to have its
own dependence on the dose rate, it is not possible to rule out the
linear, no-threshold model. The metabolic pathways in man may be
different than those in the animals studied.
4. VC-22, VC-27, VC-29, VC-32, VC-34
Comment: The risk assessment should have used the much lower
ambient concentrations measured in EPA's monitoring study, rather
than use diffusion modeling results.
Response: The data referred to were not available when that part
of the risk assessment was done. The decision was made to use the
diffusion modeling results, which were the best information available
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at the time. The best available estimates of vinyl chloride emissions
were also used. Diffusion modeling is a generally accepted technique
in the air pollution field. The fact that two independent groups
produced very similar results added to confidence in the diffusion
modeling (although both are based on the same estimates of total
emissions).
The risk assessment made clear that the situation with uncontrolled
plants was being evaluated. The EPA monitoring in question occurred
after the OSHA standard had been promulgated, so that the plants may
have been operating more carefully to limit workers' exposures. It also
occurred during an economic recession, during which production rates
may have been less than full capacity. It seems doubtful, however, that
these factors can account for a difference as large was was observed.
In any future revision of the risk assessment, the monitoring data
will be taken into account. It is possible that if this were done,
the risks would be approximately one-tenth of the current estimates.
It should be noted that the risk assessment is not required by
the Act and that the standard is not derived from it in any direct
sense. It forms part of the background information available to the
Administrator in deciding on the seriousness of the problem of vinyl
chloride emissions.
2. VC-22, VC-23a, VC-29, VC-34
Comment: What importance should be attached to the negative finding
in the risk assessment document of liver angiosarcoma cases clustered
around ethylene dichloride-vinyl chloride and polyvinyl chloride plants?
Response: The risk assessment document described a survey of liver
angiosarcoma cases in which evidence of higher than average clustering
of cases among people living near ethylene dichloride-vinyl chloride
and polyvinyl chloride plants was sought but not found. The document
concluded that, for several reasons, the survey was not sensitive
enough to detect such clustering even if it did occur, unless the
actual rate of vinyl chloride induced angiosarcoma is many times greater
than the maximum rate predicted by the model.
Industry comments generally interpreted the survey as evidence
that cancer is not caused by community exposure to vinyl chloride, and
a comment from an environmental group pointed out factors not considered
in the document which would make the survey even less sensitive than
stated.
One industry comment alleged, but could not support this definite
information, that the ambient concentration at some plants could have
been more in past years than in 1974. Another industry stated that
at one plant emissions did not change appreciably from the early
1950's to 1974, and consequently estimated that the risk to that
community has not increased in this period.
2-109
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In order to make the risk estimate more realistic, the Agency
would need reliable information about historical vinyl chloride and
polyvinyl chloride production rates at each factory site. Because such
localized information is not available, the document draws conslusions
only about national averages. The comments received were not extensive
enough to invalidate the assumption that the average vinyl chloride
concentrations were proportional to the polyvinyl chloride and vinyl
chloride production rates. Therefore people in recent years have been
exposed to higher vinyl chloride concentrations and the conclusion
still remains that surveys conducted now cannot detect a large portion
of cancers that may have already been initiated by vinyl chloride
exposure.
The environmental group commented that the latent period is probably
longer for people exposed to low community vinyl chloride concentrations
than for those occupationally exposed (a factor ignored in the risk
document), so that any community cases observed in the survey would
represent exposures earlier, and therefore, at lower ambient concentra-
tions than stated in the risk document. If the Agency had considered
this factor, a stronger case could be made for rejecting the survey
conclusions and, therefore, for being unable to rule out the possibility
of vinyl chloride induced cancer in the community.
The Agency has decided that, since no new data on these points
was submitted by the industry groups or the environmental group, the
risk document should still leave open the possibility that vinyl
chloride could have induced cancer in people living near plants which
is currently undetectable in the population.
5. VC-32, VC-37
Comment: In estimating the incidence of liver angiosarcoma among vinyl
chloride and polyvinyl chloride workers, the risk document selected
studies showing the highest incidence and ignored those showing lower
incidence in order to artificially increase the risk estimates.
Response: The objective of the literature survey of occupational
cases was to obtain the incidence of liver angiosarcoma in a homogenous
population of workers who were all highly exposed to vinyl chloride in
a situation where the concentration could be estimated. Of the
four studies found where the incidence of angiosarcoma among.highly
exposed workers could be calculated, one was a large study of 33 plants,
each with its own definition of high exposure. It was rejected
because the population was too heterogeneous and because of the resulting
difficulty in establishing an exposure level for the group. A second
study of two plants with a group of workers almost as large as the
first group but with no evaluation of separate job categories reported
all types of liver cancer. It was rejected because of the large mix
of job categories in the population. The remaining two studies were
both restricted to workers directly exposed to high concentrations of
vinyl chloride. The incidence rates in these two studies were similar
2-110
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and higher than the two larger studies that were rejected. These
rates are consistent with the hypothesis that the larger populations
had a heterogeneous mixture of jobs with a range of exposures.
Unfortunately we had to go to a third study in order to estimate
the concentration of vinyl chloride to which this occupational group
was exposed. . ,:
Therefore, the selection of studies was necessary, in order to
arrive at an incidence rate which was valid for a population exposed
to a known vinyl chloride concentration.
6. VC-23a, pp. 9-10 of EDF testimony
Comment: The risk assessment may understate the risk because it
does not reflect the effects of pre-natal and childhood exposure,
possible synergistic effects, or the effects of adult exposure
for entire lifetimes.
Response: Ideally, animal studies for environmental carcinogens
should involve exposure from conception to death. Unfortunately,
the animal data on vinyl chloride were designed to simulate
occupational rather than environmental exposure. For the risk
assessment, it was necessary to do what was possible with the
available data.
There is no data that would make possible an estimate of .<
different susceptibility of fetuses or young children to the
carcinogenic activity of vinyl chloride, or of possible synergistic
(or antagonistic) effects of other environmental agents. Hence,
such factors were not included in the calculations; the comment is
correct that this is an additional source of uncertainty in the
estimates. It is not possible to be sure that they would lead to
higher estimates of effects.
The problem of limited adult exposure duration, one year for
rats, up to 30 years or so for humans, was handled in a conservative
way in the risk assessment. It was assumed that each period of
exposure would have the same probability of causing cancer after
correcting for species lifetime effects as that observed in the
animal experiments, where young rats were exposed for about half
their lifetime. This leads to an overstatement of the actual risk
because of the long latency period, since pre-cancerous changes
occurring late in life are less likely to cause clinical disease
before death intervenes from other causes.
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2.11 Miscellaneous
1. Comment: Several commentators pointed out typographical,
editorial, and conversion factor errors in the proposed standard.
The errors have been corrected in the promulgated standard and are
listed below along with the commentators that pointed them out.
1. The conversion factor for liters to gallons is 3.8 1/gal,
not 4.1 or 4.4 1/gal. VC-14, VC-21, VC-26, VC-27, VC-29, VC-32.
2. The word "chloride" was left out of §61.64 (e)(l)(i).
VC-13, VC-29.
3. In §61.65 (b)(3)(iii) and (iv) in the phrase "so that
any leak that occurs is into the pump," the word "pump" should be
replaced with "compressor" and "agitated vessel," respectively.
VC-25, VC-35.
4. §61.70(a)(4) should refer to §61.65(a) instead of
S61.65(b). VC-21, VC-31.
31.
5. §61.65(c) should refer to equipment >_ 5500 1 (1250 gal). VC-
6. There should be a paragraph following §61.67 explaining
that Test Methods 106 and 107 are being added to Appendix B of
Part 61. VC-35.
7. §61.65(b)(9)(i) should be corrected to say "inprocess
wastewater stream is to be reduced to 10 ppm" instead of "by 10 ppm."
(emphasis added) VC-35. -*-
There were also some errors pointed out in supporting documents.
1. In the STAR document, the nameplate capacity of Shell Chemical
Company's plant in Deer Park, Texas should be 380 x 10 kg/yr instead of
410 x 10 kg/yr. VC-27.
2. In Table I of the "Quantitative Risk Assessment for
Community Exposure to Vinyl Chloride," entries 65 and 66 are incorrect.
With regard to entry 65, Tenneco does not have a vinyl chloride or
polyvinyl chloride plant in Painesville, Ohio, and therefore this
entry should be eliminated from the Table. With regard to entry
66, Tenneco does have a facility at Pasadena Texas, but that facility
manufactures only polyvinyl chloride; it does not manufacture vinyl
chloride. VC-15.
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2. VC-18, VC-29, VC-30
Comment: Under the provisions of section 112 of the Clean Air Act,
EPA may grant a waiver of compliance with a standard for a period
not exceeding two years from the effective date of the standard.
Plant owners and operators will need to take advantage of this
provision.
Response: No response necessary.
3. VC-13, VC-25
Comment: The definition of "in vinyl chloride service" in §61.61(1)
of the proposed standard should be revised in the following three
ways.
(1) Add the qualification that the equipment must be operating
under pressure. A piece of equipment that is not operating above
atmospheric pressure cannot emit vinyl chloride to the atmosphere.
(2) The words contain vinyl chloride should be changed to
contacts vinyl chloride. As an example an agitator does not contain
material, but contacts the material being agitated.
(3) The qualification should be added that the principle phase
of the contents of the equipment contains 10 percent vinyl chloride.
The basis for this suggestion is to alleviate problems with vessels
that contain stripped-to-specification slurries (the principle phase)
but whose vapor space at the low pressure still might contain
10 percent by volume of vinyl chloride.
Response: The definition of "in vinyl chloride service" has been
revised to incorporate the second suggestion, but not the first
or third. EPA intends to cover the situation described in the
third suggestion. The benefit of adding the first suggestion is
not apparent.
4. VC-28
Comment: Clarification on the following two questions is requested:
(a) Once the residual vinyl chloride levels of 400 ppm for
suspension resins and 2000 ppm for dispersion resins are met,
may fugitive emission sources from equipment downstream from the
reactor (reactor/stripper), exceed 10 ppm?
Response: If the 400 ppm and 2000 ppm limits have been met in the
stripper, the fugitive emission limits do not apply to equipment
downstream of the stripper.
2-113
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(b) Once a vessel is evacuated to the required level for
opening, may the remaining vinyl chloride be collected to a system
whose stack exit concentration exceeds 10 ppm.
Response: Yes. The vinyl chloride removed from the equipment
in order to meet the requirement for opening must be treated
to meet the 10 ppm limit. The vinyl chloride remaining in the
equipment after the requirement for opening is met is allowed to go
to the atmosphere. It is assumed that the commentator is referring
to a purging hose which is typically used by the industry to remove
any remaining vinyl chloride from the reactor. Emissions from other
sources may not be mixed with the reactor opening loss and exceed
the 10 ppm limit.
5. VC-14, VC-26, VC-32, VC-34, VC-39
Comment: The equipment specifications for fugitive emission sources
are not authorized under section 112 of the Clean Air Act. VC-34
states that the only fugitive emission regulation that is worthwhile
is the one requiring leak detection. Just requiring a leak detection
program would allow plants more latitude than the proposed regulation
in controlling fugitive emissions.
Response: In the preamble to the proposed standard, EPA explained
in detail why it had decided to regulate some fugitive emission
sources with equipment specifications. Numerical emission limits
were used for each emission point where possible; however, equipment
and operating procedures are specified for some of the fugitive
emission sources from which emissions cannot be measured or
calculated or for which it would be grossly impractical to do so.
Generally, the reason that these emissions cannot be measured is
that they are released into an unconfined area and often from many
small sources, and there is no practical testing procedure for
obtaining a reliable reading of emission levels. Where equipment
or operating procedures are specified, plant owners or operators are
generally allowed to use other equipment or procedures, demonstrated to be
of equivalent effectiveness. Primarily because fugitive emissions
compose such a large proportion of the total emissions at ethylene
dichloride-vinyl chloride plants, EPA has determined that control
of such emissions by specification of equipment and operating procedures
is preferable to the alternative of leaving such emissions unregulated.
6. VC-46
Comment: The environmental impact statement was prepared after
standards were proposed and published in the FEDERAL REGISTER.
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Response: Drafts of the environmental impact statement were
available to interested parties as early as March 1975. The
information in these drafts was the basis of the proposed
standard.
7. VC-46
Comment: Reference is made to one company in Chapter 2. Naming
one plant out of several is inappropriate. The term "Vulcan
Materials" should be substituted by an appropriate synonym so as
to read "with the exception of one plant."
Response: The suggestion is probably appropriate. However,the
document is not being rewritten, so this change will not be made.
8. VC-46
Comment: It should be stated that the total emissions from the
vinyl chloride plant are one-third of the emissions from the polyvinyl
chloride fabricating plants.
Response: Table 2-1 on page 2-28 of the Standard Support Document lists
the 1974 vinyl chloride emissions from ethylene -dichloride-vinyl chloride
plants as being 11 million kg per year and from polyvinyl chloride
fabricating plants as being 600,000 kg per year.
9. VC-46
Comment: In Chapter 2, it is stated that "all vinyl chloride emissions
from the fabricating plants are due to residual vinyl chloride in the
raw materials coming from polyvinyl chloride plants." This statement is
incorrect. Emissions in fabricating plants result from the vinyl
chloride contained in the raw polyvinyl chloride used in the fabri-
cation.
Response: The difference between the two statements is unclear.
10. VC-45
Comment: The data from the ambient sampling program around Shell's
ethylene dichloride-vinyl chloride plant is not included under the
data for Region VI on page 27 of the STAR document.
Response: This data ijs on page ,30.
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11. VC-45
Comment: The ambient sample data reported from grab samples
in Tedlar bags is totally unreliable. If the grab sample
data is going to be referred to or tabulated in the report,
there should be some reference made to the use of a bag containing
plasticizers. 3 y
Response: The fact that Tedlar bags contain plasticizers should
not be a_problem. EPA conducted a study under contract on Tedlar bags
and alunnmzed Milar bags. Samples containing specified quantities of
vinyl chloride were placed in bath the Tedlar and aluminized Milar bags
for a period of one month. The Tedlar bag showed no loss or increase of
vinyl chloride. It also did not show peaks due to decomposition
products from the bag. The Milar bag did, however. Zero concentrations
of vinyl chloride were also placed in the Tedlar bags and no response
was observed.
The vinyl chloride content of the Tedlar bags used during the
sampling program was measured with gas chromotography and in
some cases cross-checked with mass spectrometry. Based on the
study discussed above, it is unlikely that the plasticizers in the
bags caused interference with the vinyl chloride peak on the
gas chromatograph.
12. VC-39
Comment: It is unfortunate that EPA could not and did not visit
all plants. As a result, the commentator's plant was not
given sufficient recognition within the regulation as
utilizing the best available technology.
Response: Time did not permit EPA to visit all plants. The SSEIS,
Vol. I does not characterize individual plants, but only the
average plant. Since the comment letter was received, EPA has visited
this particular plant. The plant does have many of the control systems
required by the standard, particularly for the fugitive emission
sources and relief discharges.
13. VC-39
Comment: The regulations should state the emission reduction
possible for the entire class or category of point sources
within a given range and should analyze those factors deemed
important for the writing of each individual compliance schedule
within that range. More consideration needs to be given
to formulating a more detailed approach for the issuance of
each compliance schedule.
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Response: The specifics for the compliance schedules are in
§§61.10 and 61.11 of the general provisions.
14. VC-18, VC-24, VC-335 VC-34
The standard should provide for variances for infrequent
operations that produce small emissions. An example would
be the requirement to strip vinyl chloride from water which
has been used to purge vinyl chloride from a storage sphere
before opening it.
The standard should provide for excess emissions during
start-up, shut-down, and malfunction. EPA has not included
in its economic impact statement the costs which would be
incurred during a malfunction either to shutdown production
or to install back-up control equipment.
EPA should at least provide for excess emissions during a
shutdown. If a breakdown occurs in the emission control
equipment, there are on-going reactions in a plant that must
be brought to completion prior to shutdown. This will require
venting in excess of 10 ppm until a safe shutdown can be
accomplished or the malfunction in the control system corrected.
One option would be to have a steam factor of 0.9 with
a maximum emission limit of 0.04 kg/100 kg. of product produced
during noncompliance,, This option would allow operators to
repair, maintain, and modify operation of control devices that
malfunctioned or required preventive maintenance without
terminating production or otherwise seriously disrupting operations.
In our plants (VC-18) this would cause a maximum increase in
annual emissions of about 10 percent at the polyvinyl chloride
plant and about 20 percent at the ethylene dichloride-vinyl
chloride plant.
Response: (1) Variances.
There are no provisions at the present time for variances
for standards promulgated under sections 111 or 112. The water
used to purge vinyl chloride from a storage sphere would have
to be treated only if it contains more than 10 ppm vinyl chloride.
If it does need to be treated, it would not appear to be practical
to install a larger water stripper for this purpose. Storing the
water in that vessel or some other holding tank until it could
be treated seems to be a more plausible solution.
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(2) Startup and shutdown
Startup and shutdown provisions are not relevant for
polyvinyl chloride plants because startup or shutdown of the
process has essentially no effect on emissions to the atmosphere
For ethylene dichloride-vinyl chloride plants, only one comment
mentioned a source of emissions during startup which would present
control problems. During startup the hydrogen chloride stream that
is normally vented to the oxychlorination process from the cracking
furnace is vented to the atmosphere. The commentator vents the
hydrogen chloride stream to the atmosphere since the oxychlorination
process is not operating. The gas stream contains emissions in
excess of the 10 ppm standard. EPA discussed this problem with
two other companies. Both companies avoid venting the hydrogen
chloride gas stream to the atmosphere by starting up the oxychlorination
process before the cracking furnaces. There is no apparent reason why
this procedure could not be adopted by the other companies.
(3) Malfunction
Section 112 of the Clean Air Act has been reserved for the
regulation of pollutants,., such as vinyl chloride, which may cause,
or contribute to, an increase in mortality or an increase in
serious illness. Because of the serious nature of the health
effects of pollutants regulated under section 112, EPA has
determined that it would not be appropriate to consider adding
malfunction provisions to the regulation unless the Agency was
convinced that the additional emissions occurring during the malfunction
did not increase the risk of health effects. There is no conclusive
evidence to this effect for vinyl chloride. Therefore, when a
malfunction occurs, compliance with the vinyl chloride regulation
consists of promptly shutting down.
It could be argued that EPA, in providing for emergency relief
discharges, in effect provided for excess emissions during some types of
malfunctions. Emergency relief discharges, however, are in a different
category. Safety considerations require the use of relief valves on
equipment in which vinyl chloride is processed or stored under pressure
There are several preventive measures which can be undertaken to reduce
the pressure in the equipment to prevent a relief discharge. In cases
where these preventive measures have been undertaken, and the pressure
continues to build-up in the equipment, the standard allows relief
discharges. Relief valves discharge only the amount of vinyl chloride
necessary to reduce the excess pressure in the equipment. The alternative
would be rupture of the equipment and release of its total contents, and
perhaps fire.
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15. VC-35
Comment: Clarify what emissions are to be measured on a continuous
basis.
Response: A monitoring device is required to measure vinyl
chloride concentrations at certain points within the plant on
a continuous basis. Typically this involves a central analyzer
with twenty or more sampling points. The purpose of this requirement
is leak detection. EPA's standard requires that sampling points
also be located in the stacks to measure outlet concentrations on
a continuing basis.
Reactor opening emissions and stripped resin samples are
also required to be measured on a continuing basis, but this
is not related to the vinyl chloride monitoring device. Testing
methods are specified for each of the sources.
16. VC-35
Comment: Regarding the absence of a proposed standard for polyvinyl
chloride particulate and EPA's determination that direct regulation
of the particulate is unnecessary, the following is provided:
"A recent complaint received was about a polyvinyl chloride
fabricating plant indicating that accidental intermittent release
of polyvinyl chloride particulate emissions, because of process
malfunction, were impacting the surrounding ambient air to which
the public has access. Serious concern therefore is expressed for
the respiration or inhalation of the polyvinyl chloride particulate
and any carcinogenic health effects that may result from residual
vinyl chloride in the particulates, especially where such emissions
are common occurrences and complacency is found in efforts to
correct such accidental emissions.
Clarification of carcinogenic health effects of polyvinyl
chloride particulate, with appropriate regulation, is recommended
as soon as health effects data from NIOSH are evaluated.
Response: In the preamble to the proposed standard, EPA stated
that additional information may indicate a need to regulate
polyvinyl chloride particulate. The information submitted by the
commentator is appreciated.
2-119
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17. VC-32
Comment: The preamble to the proposed standard states
(40 FR 59543) that studies show that polyvinyl chloride
particulate "may possibly" cause pneumoconiosis. Stiles and
Wilson [Ann. Occup. Hyg. 16: 241 (1973] clearly demonstrated
no such effect from polyvinyl chloride dust.
Response: The studies EPA referred to include:
1. B. B. Szende, et. al.; "Pneumoconiosis Caused by the
Inhalation of Polyvinyl Chloride Dust," Med. Lavoro,
Vol. 61, no. 8-9, 1970; p. 433.
2. Yu. J. Verthin and Yu. R. Mamontov, "On the State of
the Bronchopulmonary System in Workers Engaged in the
Manufacture of Articles Made of Polyvinyl Chloride,"
Gigiyena Tudor) Vol. 14, No. 10, 1970, pp. 29-32.
EPA will await additional studies being conducted by
NIOSH to determine the need to regulate polyvinyl chloride
particulate.
18. VC-32
Comment: It is not clear from the discussion in section 4.9
of the SSEIS, Vol. I which decision was reached on reactor opening
emissions since no statement is made as to the final conclusion, but
from section 4.12.5 and Table 7.8 It is assumed that the gasholder was
chosen. Substantially the same effect can be obtained by the use of
vacuum pumps, which can reduce the internal pressure well below 100 mm
Hg absolute, to give a reduction of vinyl chloride vapor in the reactor
of at least 87 percent. An expenditure of over $1.5 million per plant
is an excessive price to pay for the additional 12 percent reduction of
an estimated loss of 3.6 percent of the total. This requirement should
be omitted.
Response: The type of control used to meet the reactor opening
standard is left up to the plants. Water purge and vacuum are
both control methods that can be used to meet the standard. Plants
will be expected, however, to have gasholders or some other
empty vessel for prevention of reactor relief discharges.
19. Proceedings of Public Hearing, Presentation by
Barry Castleman, p. 30.
Comment: I would be interested in knowing from EPA what the
update situation on vinyl chloride and livestock is.
2-120
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Response: EPA and the Department of Agriculture are co-sponsoring
a study to determine whether vinyl chloride appears in food supplies
due to livestock living near polyvinyl chloride plants.
,20. VC-49
Comment: Are all treatment ponds carefully lined and sealed
to prevent leakage to ground water? If not, the significance
of reported zero concentrations of effluents from the ponds may
need to be reexamined.
Response: According to one company, they have two types of ponds.
For one type the bottom is one foot thickness of compacted
impermeable clay. These ponds are located in the same area with
wells. No vinyl chloride has been detected in the water from the
wells. For the second and newer type, the bottom is composed
of an impermeable polypropylene liner.
21. VC-49
Comment: In general under the proposed standard, the low
density of the vinyl chloride is counted upon to permit
escape of the substance from water into air. That is, removal
is to be accomplished by stripping and evaporation. The length
of time that a free water surface is available may require
consideration as the temperature, the flow conditions, such as
turbulence, before infiltration to groundwater or confinement
of surface flow can occur, should be assessed. Flow conditions
of water discharge from a plant may prevent escape to the air,
either by confinement or local pressure conditions. Quick
infiltration or restraint of surface flow of the water bearing
vinyl chloride might prevent escape of the chemical as a result
of such factors as pressure condition, aquifer texture, and
sorption properties with respect to sediments, carbon, etc.
Although removal is estimated to be essentially complete,
monitoring in specific situations is needed to verify this
conclusion.
Response: As stated by the commentator, there are multiple
factors which influence the rate at which vinyl chloride is
transferred out of water into the air. These factors should
be taken into account when designing the water stripper used
to meet EPA's standard. EPA has conducted studies on the
behavior of vinyl chloride in water. A report on this
study entitled Dynamic Behavior of Vinyl Chloride in
Aquatic Systems has been prepared (January 1976) and is
available from the Environmental Research Laboratory, Office
of Research and Development, EPA, Athens, Georgia, 30601. The
conclusions of this study are discussed on page 6-45 of the
SSEIS, Vol. I.
2-121
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-450/2-75-009b
2.
3. RECIPIENT'S ACCESSIOt*NO.
l-TJTLEjAND SUBTITLE . , _ . - T , - , ,
Standard Support and Environmental Impact Statement,
Volume 2: Promulgated Emission Standard for Vinyl
Chloride
5. REPORT DATE
September 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Research Triangle Park, N. C. 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A national emission standard for vinyl chloride emitted from ethylene
dichloride-vinyl chloride and polyvinyl chloride plants is being promulgated under
the authority of section 112 of the Clean Air Act. Vinyl chloride has been implicatec
as the causal agent of angiosarcoma and other serious disorders, both carcinogenic anc
noncarcinoge.nic, in people with occupational exposure and in animals with experimental
exposure to vinyl chloride. Reasonable extrapolations from these findings cause
concern that vinyl chloride may cause or contribute to the same or s.imilar HisnrHpr<=
at present ambient air levels. The purpose of the standard is to minimize vinyl
chloride emissions from all known process and fugitive emission sources in ethylene
dichloride-vinyl chloride and polyvinyl chloride plants to the level attainable with
best available control technology. This would have the effect of furthering the pro-
tection of public health by minimizing the health risks to the people living in the
vicinity of these plants and to any additional people who are exposed as a result of
new construction. This is estimated to have the effect of reducing emissions from a
typical- ethylene dichloride-vinyl chloride plant by approximately 94 percent and from
a typical polyvinyl chloride plant by approximately 95 percent. This document
contains a summary of the public comments on the proposed standard and EPA's responses
to the comments. It also contains updated information concerning the environmental
and inflationary impacts of the standard.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air pollution
Pollution control
Hazardous pollutants
Emission standards
Vinyl chloride
Vinyl chloride plants
Polyvinyl chloride plants
Ft.hylpnp-Hi rhl nyi HP
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air pollution control
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)'
Unclassified
21. NO. OF PAGES
134
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
3-1
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