EPA-450/3-89-31
Benzene Emissions from Coke
By-Product Recovery Plants, Benzene Storage
Vessels, Equipment Leaks, and Ethylbenzene/
Styrene Process Vents - Background Information
and Responses to Technical Comments
for 1989 Final Decisions
Emissions Standards Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
August 1989
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This report has been reviewed by the Emissions Standards Division of the Office of Air Quality Planning and
Standards, EPA, and approved for publication. Mention of trade names or commercial products is not
intended to constitute endorsement or recommendation for use. Copies of this report are available through
the Library Services Office (MD-35), U.S. Environmental Protection Agency, Research Triangle Park, North
Carolina 27711; or, for a fee, from the National Technical Information Services, 5285 Port Royal Road,
Springfield, Virginia 22161.
ii
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ENVIRONMENTAL PROTECTION AGENCY
Benzene Emissions from Ethylbenzene/Styrene Process Vents, Benzene
Storage Vessels, Equipment Leaks, and Coke By-Product Recovery Plants -
Background Information and Responses to Technical Comments for
1000 Final Decisions, and Final Environmental Impact Statement
Jack/ft". Farmer
Director, Emission Standards Division
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
1. Final decisions have been made on regulation of benzene emissions from
existing and new coke by-product recovery plants, benzene storage
vessels, equipment leaks, and ethylbenzene/styrene process vents These
decisions implement Section 112 of the Clean Air Act and are based on
the Administrator's determination of June 8, 1977 (42 FR 29332) that
benzene presents a significant risk to human health as a'result of air
emissions from one or more stationary source categories, and is
therefore a hazardous air pollutant. Regions II, III, IV, V, and VI
will be the most affected, because most of the facilities subject to the
regulations are located in those regions.
2. Copies of this document have been sent to the following Federal
Departments: Health and Human Services, Defense, Transportation,
Agriculture, Commerce, Interior, and Energy; the Council on
Environmental Quality; members of the State and Territorial Air
r«UU ti°n^°?r1am Administrators; the Association of Local Air Pollution
Control Officials; EPA Regional Headquarters; and other interested
parties.
3. For additional information contact:
Fred Dimmick
Standards Development Branch (MD-13)
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
Telephone: (919) 541-5625
4. Copies of this document may be obtained from:
U. S. EPA Library (MD-35)
Research Triangle Park, NC 27711
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
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TABLE OF CONTENTS
Chapter
1.0 INTRODUCTION
2.0
3.0
4.0
5.0
LEGAL ARGUMENTS.
Page
1-1
2-1
ETHYLBENZENE/STYRENE (EB/S) PROCESS VENTS ........ 3-1
BENZENE STORAGE VESSELS. . . . . . ..... ...... 4-1
EQUIPMENT LEAKS.
6.0 COKE BY-PRODUCT RECOVERY PLANTS. ............ 6-1
7.0 RISK ASSESSMENT. ... 7-
1
8.0 FORMATS AND COMPLIANCE PROVISIONS OF STANDARDS
APPENDIX A. LIST OF COMMENTERS.
8-1
A-l
v
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1.0 INTRODUCTION
This background information document (BID) contains information about
the U. S. Environmental Protection Agency's (EPA) final actions regarding the
proposed standards for benzene emissions from ethylbenzene/styrene (EB/S)
process vents, benzene storage vessels, benzene equipment leaks, and coke
by-product recovery plants. On July 28, 1988, EPA proposed national emission
standards for benzene emissions from these four source categories under
authority of Section 112 of the Clean Air Act (CAA). Public comments were
requested in the Federal Register (53 FR 28496). There were about
275 commenters composed mainly of industries, trade organizations, State and
local government agencies, environmental and public interest groups, and
private citizens. A list of the commenters and the index listing in the
docket are given in Appendix A. The technical comments that were submitted,
along with responses to these comments, are summarized in this document.
1.1 BACKGROUND
Benzene was listed as a hazardous air pollutant under Section 112 of the
CAA in June 1977. In June 1984, EPA promulgated standards for benzene
equipment leaks and withdrew proposed standards for EB/S process vents,
benzene storage vessels, and maleic anhydride process vents. The Natural
Resources Defense Council (NRDC) filed a petition in the U. S. Court of
Appeals for the District of Columbia Circuit asking EPA to reconsider these
actions (Natural Resources Defense Council, Inc. v. Thomas. No. 84-1387 [also
referred to as "Benzene"!). This petition was denied by EPA in August 1985.
In 1987, EPA was granted a voluntary remand in Benzene to reconsider
these standards in light of the District of Columbia Court's decision on the
vinyl chloride standard (Natural Resources Defense Council. Inc. v. EPA.
824 F.2d at 1146 (1987) [also referred to as Vinvl ChlorideH. The EPA also
decided to reconsider the standards proposed in June 1984 for benzene
emissions from coke by-product recovery plants. The Vinvl Chloride case
established a two-step process in setting national emission standards for
hazardous air pollutants (NESHAP): (1) to determine a "safe" or "acceptable"
1-1
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risk level without regard to cost or feasibility, and (2) to set the standard
at a level that provides an ample margin of safety to protect public health.
Cost, feasibility, and other relevant factors can be considered in this
second step along with the information considered in the first step.
On July 28, 1988, EPA proposed four alternative policy approaches to
setting NESHAP that would be consistent with the Vinvl Chloride decision.
Under each policy approach, decisions on the risk levels that are "acceptable"
and that provide an ample margin of safety were made for each of the source
categories above based on the Vinvl Chloride two-step process. No standards
were proposed for maleic anhydride process vents under any approach because
benzene is no longer used to produce maleic anhydride.
The four proposed alternative policy approaches are briefly noted below:
(1) Approach A - a case-by-case approach which considers
all the health, risk, and exposure information,
including incidence, maximum risk, risk distribution,
and uncertainties in the risk assessment in determining
the level of acceptable risk for each source category;
(2) Approach B - an incidence-based approach which
establishes an acceptable risk level at 1 case per
year (case/year) per source category;
Approach C - a risk cut-off approach which sets a
(3)
(4)
maximum individual lifetime risk (MIR) of 1 x 10~4
or lower as the acceptable risk level; and
Approach D - a more stringent risk cut-off approach
with a MIR of 1 x 10"6 or lower as the acceptable
risk level.
Following the acceptable risk decision, under each approach, additional
factors are considered in determining whether an ample margin of safety is
provided.
Table 1-1 summarizes the standards proposed for the four source
categories under the four proposed policy approaches. As shown on the table,
under some approaches, it was determined that some source categories did not
1-2
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1-3
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require regulation to achieve an acceptable risk level and provide an ample
margin of safety (e.g., EB/S process vents under Approaches A, B, and C). In
some cases, equipment and work practice standards were proposed to achieve an
ample margin of safety (e.g., benzene storage vessels under Approaches A, B,
and C). In other cases, plantwide emission limits were proposed (e.g., all
source categories under Approach D) because specific measures to achieve the
desired emission level could not be identified.
Public comment was solicited and received on the proposed policy
approaches, technical issues, and the format selected for the standards.
Policy comments and the rationale for the final policy approach are discussed
in the Federal Register notice announcing the final standards, rather than in
this BID. Comments of a technical nature are summarized and responded to
here. These include certain legal comments, comments on control techniques,
emissions, costs, etc., for each of the four source categories, comments on
risk assessment, and other miscellaneous comments. All docket item numbers
listed in this BID without a docket number are contained in Docket
No. OAQPS-79-3, Part I. Whenever another docket is referred to, both the
docket number and the docket item number are given.
1.2 SUMMARY OF FINAL STANDARDS AND IMPACTS
No standards are promulgated for maleic anhydride or EB/S process vents.
No additional standards are promulgated for benzene equipment leaks beyond
those contained in 40 CFR 61 Subpart J. The final standards for coke by-
product recovery plants and benzene storage vessels and the associated
health, environmental, energy, cost, and economic impacts are summarized
below.
1.2.1 Coke Bv-Product Recovery Plants
Summary of Standards: The final regulations, in 40 CFR 61 Subpart L,
establish equipment standards for the control of emissions from each tar
decanter, tar dewatering tank, tar-intercepting sump, tar storage tank,
flushing-liquor circulation tank, light-oil condenser, light-oil decanter,
wash-oil decanter, and wash-oil circulation tank. These standards also apply
to storage tanks containing benzene, benzene-toluene-xylene (BTX) mixtures,
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light-oil, or excess ammonia-liquor at furnace coke by-product recovery
plants. "Furnace coke" and "foundry coke" are defined in the regulations to
identify plants subject to controls for these storage tanks. Each of these
sources are required to be totally enclosed with emissions ducted to the gas
collection system, gas distribution system, or other enclosed point in the
by-product recovery process. Unless otherwise specified, pressure-relief
devices, vacuum-relief devices, access hatches, and sampling ports are the
only openings allowed on each source. Access hatches and sampling ports must
be equipped with a gasketed cover.
The standards for these sources are achievable with the use of a gas
blanketing system. A gas blanketing system is a closed system operated at
positive (or negative) pressure and is generally composed of piping,
connections, and flow-inducing devices (if necessary) that transport
emissions from the enclosed source back to the coke-oven battery gas holder,
the collecting main, or another point in the by-product recovery process.
Dirty or clean coke oven gas, nitrogen, or natural gas are examples of gases
that may be used as the gas blanket.
'To ensure proper operation and maintenance of the control equipment,
Subpart L requires a semiannual inspection of the connections and seals on
each gas blanketing system for leaks, using EPA Method 21 (40 CFR Part 60,
Appendix A). Monitoring also is required at any time after the control
system is repressurized following removal of the cover or opening of any
access hatch. For the gas blanketing system, an organic chemical concen-
tration of more than 500 parts per million by volume (ppmv) above a
background concentration indicates the presence of a leak. The standards
also require a semiannual visual inspection of each source and the piping of
the control system for visible defects such as gaps or tears. A first
attempt at repair of each leak or visible defect is required within 5 days of
detection, with repair within 15 days. The owner or operator is required to
record the results of the inspections for each source and to include the
results in a semiannual report. The standards also require an annual
maintenance inspection for abnormalities such as pluggages, sticking valves,
and clogged or improperly operating condensate traps. A first attempt at
1-5
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repair is required within 5 days, and any necessary repairs are to be made
within 15 days of the inspection.
Equipment standards are also established for the control of emissions
from light-oil sumps. The standards require that the surface area of each
sump be completely enclosed. These standards are based on the use of a
tightly fitting permanent or removable cover, with a gasket on the rim of the
cover. The standards allow the use of an access hatch and a vent in the sump
cover. However, any access hatch must be equipped with a gasket and with a
cover or lid, and any vent must be equipped with a water leg seal, pressure-
relief device, or vacuum-relief device. Semiannual inspections of the
gaskets and seals for detectable emissions are required; monitoring also is
required at any time the seal system is disturbed by removal of the cover.
The inspection and monitoring requirements are the same as previously
described for gas-blanketed sources. The standards do not allow venting of
steam or gases from other points in the coke by-product process to "the
light-oil sump.
For furnace and foundry coke by-product plants, the standards for
naphthalene processing operations, final coolers, and the associated cooling
towers require zero emissions from the final cooler and cooling tower, as
well as from naphthalene processing. These standards are based on the use of
a wash-oil final cooler; however, other final cooler designs that achieve the
emission limit can be used.
The standards also, apply to leaks (i.e., fugitive emissions) from new
and existing pieces of equipment in benzene service, including pumps, valves,
exhausters, pressure-relief devices, sampling connections, and open-ended
lines, all of which except exhausters comprise those components that contact
or contain materials having a benzene concentration of at least 10 percent by
weight. Exhausters that contact or contain materials having a benzene
concentration of at least 1 percent by weight also are in benzene service.
Because the standards for equipment leaks are the same as the requirements in
40 CFR 61 Subpart V, for equipment except exhausters, the Subpart L for coke
by-product recovery plants references Subpart V where appropriate rather than
repeating the provisions. Subpart V also has been amended where necessary
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for clarification of the cross referencing. The specific requirements for
exhausters are summarized in detail below, because they are not in Subpart V.
The standards require that all exhausters in benzene service be
monitored quarterly for the detection of leaks. If an organic chemical
concentration at or above 10,000 ppmv is detected, as measured by Method 21,
the standards require a first attempt at repair within 5 days, with repair of
the leak within 15 days from the date the leak was detected, except when
repair would require a process unit shutdown. "Repair" means that the
measured concentration is below 10,000 ppmv.
The standards provide three types of alternatives to the leak detection
and repair requirements for exhausters. An owner or operator may: (1) use
"leakless" equipment to achieve a "no detectable emission" limit (i.e., 500
ppmv above a background concentration, as measured by Method 21); (2) equip
the exhauster with enclosed seal areas vented to a control device designed
and operated to achieve a 95-percent benzene control efficiency; or (3) equip
the exhauster with seals having a barrier fluid system. Specific
requirements for each of these three alternatives to the leak detection and
repair program are also included in the regulation.
Compliance with the standards will be assessed through plant inspections
and the review of records and reports that document implementation of the
requirements. On a semiannual basis, the owner or operator is required to
report the number of leaks detected and the number of leaks not repaired
during the 6-month period. The owner or operator is also required to submit
a signed statement in each semiannual report, indicating whether provisions
of the standards have been met for the 6-month period.
Summary of Environmental. Health, and Energy Impacts: The EPA estimates that
the final standards will reduce nationwide benzene emissions from 36 coke
by-product recovery plants by about 16,500 megagrams per year (Mg/yr), a
reduction of 97 percent from the baseline level of about 17,000 Mg/yr.
Nationwide emissions of volatile organic compounds (VOC's) (including benzene)
from these plants would be reduced by about 116,000 Mg/yr (or by about
99 percent) from the baseline level of about 117,000 Mg/yr. Implementation
of the standards is expected to reduce the annual leukemia incidence
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associated with nationwide benzene emissions from these plants from 1 case
every 6 months (2 cases/year) at the baseline level to about 1 case every
20 years (0.05 case/year), a reduction of 97 percent. The MIR would be
reduced from about 7 x 10 at baseline to about 2 x 10"4.
Implementation of the standards is expected to result in a national
energy savings of approximately 14,500 terajoules (TJ)/yr from recovered coke
oven gas, assuming recovery of at least 16 liters of gas/minute/Mg of coke/
day at furnace plants and 12 liters of gas/minute/Mg of coke/day at foundry
plants. Although an increased cyanide concentration in wastewater is expected
with the use of indirect cooling instead of direct final cooling at coke
by-product plants, the increase (about 200 grams (g)/Mg of coke) is not
anticipated to cause problems for compliance with effluent regulations.
Summary of Cost and Economic Impacts: The nationwide capital cost of the
standards for furnace and foundry plants combined is estimated at about
$74 million (1984 dollars); nationwide annual costs are estimated at
$16 million/year.
The increase incurred in the price of furnace and foundry coke as a
result of the standards is estimated to be less than 1 percent. The EPA's
economic analysis indicates that at baseline, several plants may have marginal
costs of operation greater than the price of coke. The analysis predicts
that implementation of the standards may add one more plant to this group.
However, a company decision to actually close a plant is based on a number of
factors that an economic model cannot consider, including: the premium a
plant is willing to pay for a secure, captive coke supply; requirements for a
particular coke quality; age of the batteries, foundry, or steel mill;
continued access to profits from steel production; and management's percep-
tion regarding their future costs and revenues. The EPA recognizes that
implementation of the standards could be the factor that would trigger
closure decisions at plants that are presently marginal or operating at a
loss.
1.2.2 Benzene Storage Vessels
Summary of the Standards: The final standards, in 40 CFR 61 Subpart Y, are
most similar to the standards proposed for benzene storage vessels under
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proposed policy Approaches A, B, and C. The standards require control of all
new and existing storage vessels greater than or equal to 38 m3
(10,000 gallons) used to store benzene meeting the specifications incorporated
by reference in Section 61.270(a) for industrial grade benzene or refined
benzene-485, -535, or -545. The standards do not apply to storage vessels
used for storing benzene at coke by-product recovery facilities because they
are considered under the coke by-product recovery plants NESHAP. The
standards require use of certain kinds of equipment on each type of benzene
storage vessel. Table 1-2 lists the requirements.
The benzene storage vessel standards require that fixed roof vessels
include an internal floating roof (IFR) with a continuous seal and gasketed
roof fittings. Specifically, the standards require that new fixed roof
vessels and existing fixed roof vessels to which an IFR was added after
July 28, 1988, must have IFR's with either: (1) a liquid-mounted continuous
seal, or (2) a vapor-mounted primary seal, with a secondary seal, both of
which are continuous, or (3) a mechanical shoe seal. These vessels are also
required to have gasketed roof fittings, even if they have a secondary seal.
These requirements must be met before vessel-filling for new vessels or
within 90 days of the effective date of this regulation for existing vessels.
Existing fixed roof vessels that already had IFR's on July 28, 1988, and have
vapor-mounted primary seals are not required to add secondary seals or to
have their vapor-mounted seals replaced with liquid-mounted seals. However,
existing shingled-seal IFR vessels are required to replace their shingled
seal with a continuous seal within the 90-day compliance period. All vessels
with IFR's prior to July 28, 1988, are also required to have gasketed
fittings, even if they have secondary seals. However, for these existing
vessels, the fittings can be retrofitted at the first degassing or within
10 years (whichever is first).
Owners of existing and new external floating roof (EFR) vessels would
have to install liquid-mounted primary seals (or mechanical shoe seals) and
continuous secondary seals meeting certain gap requirements. For new vessels,
these requirements must be met before vessel-filling. For existing vessels
that did not have liquid-mounted primary seals as of July 28, 1988, they must
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TABLE 1-2. EQUIPMENT REQUIRED ON BENZENE STORAGE VESSELS
BY 40 CFR 61 SUBPART Y
Vessel Size and Time of Construction
Requirements
1. Fixed IFR vessel
a. > 38 m , commenced construction,
after July 28, 1988; or > 38 m ,
commenced construction prior to
July 28, 1988, and had no IFR,
or had an IFR without a continuous
seal as of July 28, 1988.
o
b. > 38 m , commenced construction
prior to July 28, 1988, and
had an IFR as of July 28, 1988.
IFR with liquid-mounted
or mechanical shoe
continuous primary
seal and gasketed
roof fittings.
IFR with a continuous
seal and gasketed
roof fittings'3.
2. EFR vessel
3
a. > 38 m , commenced construction.
after July 28, 1988; or > 38 m6,
commenced construction prior to
July 28, 1988, and did not have
a liquid-mounted primary seal as
of July 28, 1988.
o
b. > 38 m , commenced construction
prior to July 28, 1988, and had a
liquid-mounted primary seal as of
July 28, 1988.
Liquid-mounted or
mechanical shoe
primary seal and a
continuous secondary
seal.
Liquid-mounted primary
seal and a continuous
secondary seal.
A vapor-mounted primary seal is also allowed, provided that the vessel is
also equipped with a continuous secondary seal.
'For example, liquid-mounted, vapor-mounted, or mechanical shoe seals are
allowed.
Gasketing of roof fittings is required the first time vessel is degassed.
The secondary seal is required the first time the vessel is degassed.
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be met within 90 days of the effective date of this regulation. Existing EFR
vessels already equipped with a liquid-mounted primary seal as of July 28,
1988, are required to add the secondary seal at the first degassing of the
vessel. However, those with other types of primary seals (e.g., vapor or
mechanical shoe) must add the required types of primary and secondary seals
within 90 days of the effective date of the regulation.
The standards require that each IFR vessel be inspected from inside
prior to the filling of the vessel (if it is a new vessel or is emptied to
install control equipment) and at least once every 10 years. An IFR having
defects or a seal having holes or tears would have to be repaired before
filling the storage vessel with benzene. The standards also require that the
IFR and its seal be inspected through roof hatches on the fixed roof at least
once annually. However, if an IFR were equipped with a primary and secondary
seal, the owner or operator could conduct an internal inspection every
5 years rather than perform the annual inspections. Any defects such as roof
sinking, liquid on the deck, holes or tears in the seal, or primary seal
detachment (or secondary seal detachment, if one is in service) as viewed
through the roof hatches are required to be repaired within 45 days or the
storage vessel would have to be emptied. If repair within 45 days is not
possible, and alternate storage is not available to allow the vessel to be
emptied, the owner or operator could request an extension of up to
30 additional days.
The standards also, require that, for EFR vessels, the primary seal and
secondary seal gaps be measured initially and at least once every 5 years for
the primary seal and at least once annually for the secondary seal. Condi-
tions not meeting the standards which are identified during these inspections
must be repaired within 45 days or the vessel would have to be emptied. An
extension of up to 30 days may be requested if the repair is not possible
within the 45 days allowed.
Summary of the Environmental. Health, and Energy Impacts: Under the standards
summarized above, benzene emissions from this source category are estimated
to be reduced from the baseline range of 620 to 1,290 Mg/yr to a level of
510 Mg/yr. The residual incidence of leukemia from exposure to benzene
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emissions after application of the standards is estimated to be 1 case every
25 years (0.04 case/year), and the MIR is predicted to be 3 x 10"5. This can
be compared with an incidence range of 1 case every 10 to 20 years (0.1 to
0.05 case/year) and an MIR range of 4 x 10"5 to 4 x 10"4 under the baseline
conditions.
Because the control equipment and work practices required by the
standards do not involve the generation of any wastewater or solid waste,
there are no expected impacts on water quality or solid waste disposal.
Further, no noise or radiation impacts are expected, nor are any changes in
energy use predicted.
Summary of the Cost and Economic Impacts: National capital costs of control
associated with achieving the standards are $0.66 million (1982 dollars).
The nationwide annual cost is $0.1 million/year (1982 dollars). No major
adverse economic impacts are anticipated as a result of these standards.
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2.0 LEGAL ARGUMENTS
2.1 APPROACH TO ACCEPTABLE RISK
Comment: Commenters XII-F-1, XII-F-6, XII-F-8, XII-F-9, XII-F-11, XII-F-13,
XII-D-06, XII-D-27, XII-D-28, XII-D-29, XII-D-32, XII-D-33, XII-D-34, XII-D-
36, XII-D-49, XII-D-50, XII-D-55, XII-D-57, XII-D-59, XII-D-60, XII-D-98,
XII-D-99, XII-D-220, XII-D-246, and Docket No. A-79-27, Item IX-D-04 felt
that the Vinvl Chloride decision requires the Administrator to make an
"expert judgment" regarding the emission level that will result in an
"acceptable" risk, and in doing so must determine what inferences should be
drawn from all available scientific data. These commenters felt that because
the proposed Approaches B, C, and D rely on a single measure of risk to be
used inflexibly, they are arbitrary and capricious, as they ignore other
important factors in determining acceptable risk.
Response: As the commenters point out, Vinvl Chloride requires the
Administrator to make a decision as to what is "safe" based upon "an expert
judgment with regard to the level of emission that will result in an
'acceptable' risk to health," and in so doing "must determine what inferences
should be drawn from available scientific data." 824 F.2d at 1146.
The approach chosen by the Administrator, which is described in the
Federal Register notice for the final actions associated with this document,
considers and weighs the scientific data including the uncertainties in the
risk measurements and thus conforms with Vinvl Chloride. It takes into
account not just MIR, but also incidence as a measure of risk. Both cancer
and noncancer health effects are considered. It does not rely solely on one
measurement of risk, nor is it inflexible, as it allows the various health
and risk variables to be weighed in each individual pollutant assessment.
Comment: Commenter XII-D-219 stated that the proposed Approach A directly
contradicts the Vinvl Chloride decision because it does not establish an
up-front ceiling for acceptability, but allows case-specific factors to be
evaluated before maximum acceptable risk is determined.
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Response: The Vinvl Chloride decision did not mandate any specific method
for determining acceptable risk, but merely required that it be health based.
Approach A, which would allow consideration of all health information, risk
measures, and potential biases, underlying assumptions and uncertainties in
reaching a decision regarding acceptable risk, is not in contradiction with
the Vinvl Chloride decision. Neither is it the only approach that would be
acceptable. The Vinvl Chloride court stated that the Administrator is
required to make an initial determination of what is "safe," based on his
"expert judgment with regard to the level of emission that will result in an
'acceptable' risk to health .... In this regard, the Administrator must
determine what inferences should be drawn from available scientific data
. . ." 824 F.2d at 1146. Thus, the court recognized that the acceptable risk
determination is within the expert judgment of the Administrator, and
therefore does not require an up-front ceiling for acceptability. The
available scientific data for each pollutant will vary and the Administrator
should exercise his judgment to weigh the data. This process could vary from
pollutant to pollutant. Nothing in the Vinvl Chloride decision prohibits the
Administrator from reviewing these facts independently for each pollutant.
All that Vinvl Chloride prohibits is consideration of factors other than
health, such as cost and feasibility, at the initial stage of the analysis.
2.2 TREATMENT OF UNCERTAINTY IN AMPLE MARGIN OF SAFETY STEP
Comment: Commenters XII-F-6, XII-D-27, XII-D-28, XII-D-60, XII-D-104,
XII-D-105, XII-D-197, XII-D-199, XII-D-220, and Docket No. A-79-27,
Item IX-D-04 felt that under the Vinvl Chloride decision, the ample margin
step is the appropriate place for reducing uncertainty. Therefore, according
to these commenters, EPA should use realistic or most plausible risk estimates
in the acceptable risk step, and only examine conservative upperbound
estimates in the ample margin step. Commenter XII-D-27 stated specifically
that determining a single upperbound risk estimate as a beginning for the
acceptable risk step is inconsistent with the Vinvl Chloride decision. Other
commenters felt similarly that risk estimates should be most likely rather
than upperbound values, but did not cite Vinvl Chloride as support for their
opinion.
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One commenter .(XII-D-243) rebutted these arguments on legal grounds,
stating that use of upperbound risk estimates are lawful and-consistent with
Section 112 of the CAA and Vinvl Chloride. In light of scientific
uncertainties, it is reasonable and is within the EPA's discretion to make
conservative assumptions in quantifying leukemia risks of benzene emissions.
The commenter interpreted that when stating that uncertainty should be
considered in the ample margin step, the court was referring to consideration
of unknown health effects. This is a separate uncertainty issue from the
risk assessment methodology used to quantify known health effects (e.g.,
leukemia). Commenter XII-D-243 also stated that under Vinvl Chloride
uncertainty should be considered only in the ample margin step. However, if
considered in the acceptable risk step, uncertainty should not be allowed to
become a justification for allowing higher risks. This would be contrary to
Vinyl Chloride.
Response: The Vinvl Chloride decision acknowledges that there is a degree of
uncertainty which needs to be addressed in the initial step of determining
what.is an "acceptable risk." The court said that "uncertainty about the
effects of a particular carcinogenic pollutant invokes the Administrator's
discretion under Section 112," 824 f.2d at 1153, and that:
the Administrator's decision does not require a finding
that "safe" means "risk free ... or a finding that the
determination is free from uncertainty. Instead, we find
only that the Administrator's decision must be based upon
expert judgment with regard to the level of emission that
will result in an "acceptable" risk to health. 824 F.2d
at 1164-65.
Thus the court recognized that there are uncertainties inherent in the
assessment of health risk required at the "acceptable risk" step of the
analysis, and that the Administrator must exercise his expert judgment in
evaluating those uncertainties.
The regulatory approach chosen by EPA provides for consideration of the
uncertainties inherent in the existing health risk assessments along with
other factors in reaching a determination of what is an acceptable risk.
However, uncertainty is also addressed in the second step of the analysis
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where an "ample margin of safety" must be provided for. As some commenters
have stated, this allows for protection "against incompletely understood
dangers to public health and the environment, in addition to well-known
risks." 824 F.2d at 1165. This does not, as the commenter alleges, mean
that EPA must consider the likelihood of unknown health effects, but rather
roust consider dangers "before their extent is conclusively ascertained."
824 F.2d at 1165.
Comment; Commenter XII-D-100 wrote that the Vinvl Chloride opinion states
that the duty to assure "an ample margin of safety" ... requires EPA to add
an extra measure of protection in the second step to safeguard against
uncertainties that increase the likelihood of greater danger to health. The
commenter felt that the ample margin of safety step had been interpreted by
EPA, in the application of four proposed approaches to the benzene NESHAP, as
addressing only whether the residual risk from the first-step decision
warrants any additional controls. The commenter (and Commenter XII-D-243)
stated that uncertainties which cause the unit risk assessment to be under-
estimated, and other known benzene-induced risks such as multiple myeloma,
were ignored in the proposals for the ample margin of safety decision; to
comply with the Vinvl Chloride decision, these factors need to be given
tangible weight in the ample margin of safety step.
Response; Once a determination has been made regarding what constitutes
"acceptable risk" based on health protection considerations, the Vinvl
Chloride decision provides that EPA may consider other factors including cost
and technological feasibility of controls beyond those required to reach the
"acceptable risk" level. If appropriate, EPA will then set an emission
standard which may consider technical and economical feasibility, to provide
an "ample margin of safety." This standard may be below the level found to
be "safe." 824 F.2d at 1165. The purpose of this second step in the
analysis is to "protect against dangers before their extent is conclusively
ascertained." 824 F.2d at 1165. However, the ample margin of safety is not
intended to give weight to as yet unknown health effects.
Comment; Commenter XII-D-37 urged EPA to reconsider its proposal that the
Administrator must determine acceptable levels of risk in emissions standards
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without considering cost, economic impacts, benefits of the risk-causing
activity, feasibility of control, or other factors. The commenter observed
that although mandated by the Vinyl Chloride decision, such an approach is
unprecedented.
Response: The EPA is bound to follow the holding of the Vinvl Chloride case
with respect to when and where cost, economic impacts, feasibility of
controls, and other factors may be considered. The decision is unequivocal
in that it mandates that the question of what is "safe" be answered solely on
the basis of health factors. All other information must be considered only
at the second step, where an "ample margin of safety" is provided for.
Comment: Three commenters (XII-D-34, XII-D-59, and XII-D-97), supported by
XII-D-29, XII-D-32, XII-D-36, XII-D-55, XII-D-98, XII-D-104, XII-D-197,
XII-D-199, and XII-D-250 felt that the benefits associated with a risk-
creating activity must be considered when determining whether the risk is
acceptable, and that the Vinvl Chloride decision does not preclude
consideration of these benefits. Commenter XII-D-34 stated that EPA
apparently believes, because of the court's determination that cost and
technological feasibility cannot be considered, that the Vinvl Chloride
decision precludes consideration of benefits. The commenter reasoned that
benefits are wholly separate from the cost and feasibility of control
technology. This commenter felt that the Vinvl Chloride decision mandates
that benefits be considered because it cannot be determined whether risks are
"acceptable in the world in which we live" without considering the benefits
of those risks. Commenter XII-D-34 defined benefits to include the beneficial
use—including positive health-related uses—of products produced by the
risk-causing activity; the employment of people in the manufacture of such
products; the extent to which resources committed to manufacture of the
products could be redirected or would be irretrievably lost; the degree to
which alternative products would present risks; and the degree to which
substitutes are available.
One commenter (XII-D-199) added that any rational decision about the
acceptability of a particular risk associated with a particular decision must
also consider risks associated with the alternative decisions. All health
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risk, including health risks from unemployment and economic and social
disruption caused by a regulatory alternative, and risks from substitutes can
and should be considered in the acceptable risk step. The commenter believed
that consideration of these types of health risks is allowable under Vinvl
Chloride.
An opposing viewpoint was expressed by Commenters XII-D-243 and
XII-D-254. Commenter XII-D-243 stated that consideration of the benefits of
a risk-causing activity is plainly not permissible under the Vinvl Chloride
decision. Commenter XII-D-254 stated that the Chemical Manufacturers
Association (CMA), the American Petroleum Institute (API), and others had in
various ways asserted that EPA may consider cost and flexibility in the
acceptable risk determination, which is plainly contrary to the intent of
Vinvl Chloride.
Response: The Vinvl Chloride decision clearly held that the determination of
what constitutes an acceptable risk "must be based solely upon the'risk to
health," and that "[t]he Administrator cannot under any circumstances
consider cost and technological feasibility at this stage of the analysis."
824 F.2d at 1169.
Some commenters, however, contend that certain "benefits" of the
risk-generating activity may be taken into consideration during the first
step finding of what is an acceptable risk. These "benefits" are described
as: beneficial uses of the product involved, employment created by
production, and the benefit of continuing production where substitutes are
either unavailable or are high risk items themselves.
The EPA believes that both Section 112 itself, and the Vinvl Chloride
decision construe the risk to health to refer only to health effects directly
resulting from emissions of benzene. The items the commenters call "benefits"
are better described as indirect costs or effects. The EPA is free to look
at these and any other costs or effects when considering what would constitute
an ample margin of safety. Considering these costs during the "acceptable
risk" determination process would violate the Vinvl Chloride court's holding.
Comment; One commenter (XII-D-59), supported by XII-D-29, XII-D-32, XII-D-36,
XII-D-55, XII-D-98, XII-D-104, XII-D-197, and XII-D-199, stated that the
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Vinyl Chloride court recognized that Congress did not intend Section 112 to
require EPA to create standards which would result in severe economic impacts
and social dislocation. The commenter thus felt that the policy of a
1 x 10" acceptable risk level (Approach D), which would cause widespread
plant closures and severe economic and social dislocation, would be
inconsistent with the court's opinion.
Response: The Vinvl Chloride court, held that EPA must initially make a
judgment regarding what level of emission will result in an "acceptable" risk
to health, and that in making this determination the Administrator "cannot
under any circumstances consider cost and technological feasibility."
824 F.2d at 1165. The court explained further that cost and feasibility have
no relevance to the determination of what is safe, and that if the
Administrator cannot find that there is an acceptable risk at any level then
he must set the level at zero. Thus, clearly, the court contemplated the
possibility of the EPA's action having severe economic impacts and recognized
that such a result may be necessary in certain circumstances. However, once
a safe level has been ascertained, the court allows economics to be considered
in setting an ample margin of safety, thus allowing for some minimization of
economic impact.
2.3 TECHNOLOGY FORCING REQUIREMENTS
Comment: Commenter XII-D-49 said there was no statutory basis for requiring
controls which do not significantly advance the goal of risk reduction merely
because such controls may be feasible and affordable.
Commenters XII-D-45, XII-D-97, and XII-D-250 argued that nothing in
Section 112 of the CAA suggested Congress intended technology-forcing
requirements to be applied under Section 112.
Response: The Vinvl Chloride court made it clear that cost and feasibility
are not permissible considerations in the initial decision as to what is
"safe." 824 F.2d at 1165. However, the court did not prohibit such
considerations from the determinations of what constitutes "an ample margin
of safety to protect the public health." 824 F.2d at 1155.
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Section 112(b) specifically provides that the Administrator shall
establish a standard which "in his judgment" provides an "ample margin of
safety." 42 U.S. 7412(b). Thus, the Administrator has the discretion to
determine what factors to consider in finding an ample margin of safety.
In discussing the specific language of Section 112, the Vinvl Chloride
court stated that, while the legislative history of Section 112 is ambiguous
as to the permissibility of considering cost and feasibility, the statute
itself neither permits nor prohibits any particular factor. 824 F.2d at
1157. The court concluded that:
Since we cannot discern clear Congressional intent to
preclude consideration of cost and technological feasibility
in setting emission standards under Section 112, we
necessarily find that the Administrator may consider these
factors, (emphasis added)
The court went on to say that at the second step in the process, the
Administrator may turn to questions of technological feasibility in setting
an emission standard with an "ample margin of safety," but that "it is not
the court's intention to bind the Administrator to any specific method of
determining what is 'safe' or what constitutes an Cample margin'." 824 F.2d
at 1166. Therefore, the determination of the weight to be given to
technological feasibility in deciding what constitutes an "ample margin of
safety" is within the discretion of the Administrator.
Comment: Commenter XII-D-48 felt that Congress intended the CAA to be a
technology-forcing statute, as evidenced by the previous experience with
mobile source controls. According to this commenter, the exclusion of
"feasibility" and "cost" considerations from Section 112, and the fact that
Section 112 already contains waiver provisions that allow existing sources
time to comply, support a technology-forcing approach.
Response: As was made clear by the Vinvl Chloride decision, the absence of
specific reference to cost and feasibility in Section 112 does not preclude
their consideration. Congress did not provide that these factors were not
permissible, and the Court of Appeals has found that in determining what
constitutes an ample margin of safety may be taken into account.
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The legislative history of Section 112 does not address the
technology-forcing issue specifically.
The provisions of Section 112 allowing existing sources time to comply
with new regulations is not, standing alone, evidence of Congressional intent
to require technology forcing. As a practical matter, existing sources need
time to adapt their operations to new requirements whether they are technology
forcing or not.
2.4 PROCEDURAL COMMENTS
Comment: Commenter XII-D-246 noted that Section 117(f)(3) [sic] of the CAA
provides that the Administrator should consult with the appropriate advisory
committees to the maximum extent practicable prior to publishing any standards
under Section 112 of the CAA. In particular, the commenter felt that exposure
assessment procedures suggested by API and other commenters should be
considered by EPA and reviewed by the Science Advisory Board.
Response: Section 117(c)(3) of the CAA provides for consultation with
advisory committees and independent experts "to the maximum extent practicable
within the time provided." In this case, where promulgation of the NESHAP is
governed by a strict court ordered schedule such consultation is by necessity
at least partially restricted. However, EPA has carefully considered all
comments submitted, and alternative regulatory approaches suggested, and
incorporated into the final regulations all useful changes.
2.5 LISTING OF CARCINOGENS UNDER SECTION 112
Comment: One commenter (XII-F-1, XII-D-209) challenged the policy of
regulating all carcinogens under Section 112 on the basis that there is no
known, absolutely safe level of exposure, as overly simplistic and unlawful,
ignoring the basic requirements of the CAA. He argued that this assumption
cannot be substituted for a determination of "significant risk". The
commenter explained that the 1977 amendments require a finding of "a
significant risk of harm" before a pollutant may be regulated. The commenter
further argued that data must demonstrate that the emissions in question
"make more than a minimal contribution to total human exposure". The
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commenter proposed that the "significance threshold" is higher for Section 112
pollutants than for any other section of the CAA. He maintained that the
potential health effects of pollutants regulated under Section 112 are of a
more serious nature, which narrows the number of pollutants that should be
dealt with under it. He went on to say EPA has listed hazardous air pollu-
tants under Section 112 on the basis of a very low threshold. The commenter
asserted that EPA had listed hazardous air pollutants on the basis of "an
assumption xof probable carcinogenicity coupled with human exposure' and then
attempted to mitigate the effect of those decisions by relaxing the controls
through a best available technology determination". He recommended that EPA
revise its framework for regulating hazardous air pollutants beginning with
the listing step.
Response: The EPA's decision, in 1977, to list benzene under Section 112 as
a hazardous air pollutant, was based on a review of evidence of carcino-
genicity obtained from occupational studies which led EPA to the conclusion
that there was sufficient evidence of a causal relationship between benzene
exposure and leukemia to warrant classification of benzene as a Group A known
human carcinogen. 53 FR 28505 (July 28, 1988).
The EPA continues to believe that the inclusion of benzene on the list
of hazardous air pollutants maintained under Section 112 of the CAA is
appropriate.
The assumption that there is no known totally risk-free exposure level
is, at this time, generally accepted in the scientific community, and the
EPA's acceptance of the assumption was recognized and ratified by the Vinyl
Chloride court.
Scientific uncertainty, due to the unavailability of
dose/response data and the 20-year latency period between
initial exposure . . . and the occurrence of disease, makes
it impossible to establish any definite threshold below which
there are no adverse effects to human health. 824 F.2d at 1148.
While the "no threshold" issue is a relevant consideration, EPA also evaluates
the particular evidence of carcinogenicity in each individual case before
making a decision to list a pollutant under Section 112.
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In response to the Vin^l_Chlp_ride decision, EPA has reevaluated its
approach to regulating hazardous air pollutants, and will, both here and in
the future, make an "acceptable risk" determination based exclusively on the
health effects of the substance, and then set a standard providing for an
"ample margin of safety."
2.6 OTHER COMMENTS
Comment: One-hundred and twenty-one commenters (XII-D-05, XII-D-14,
XII-D-17-C, XII-D-17-E, XII-D-17-F, XII-D-17-H, XII-D-17-K, XII-D-17-R,
XII-D-17-V, XII-D-17-W, XII-D-17-BB, XII-D-17-DD, XII-D-17-FF, XII-D-17-II,
XII-D-41, XII-D-43, XII-D-62, XII-D-65, XII-D-66, XII-D-70, XII-D-71,
XII-D-74, XII-D-75, XII-D-80, XII-D-81, XII-D-82, XII-D-90, XII-D-93,
XII-D-94, XII-D-108, XII-D-69, XII-D-110, XII-D-114, XII-D-118, XII-D-119,
XII-D-121, XII-D-122, XII-D-127, XII-D-129, XII-D-132, XII-D-134, XII-D-135,
XII-D-136, XII-D-137 XII-D-182-A thru M, XII-D-181-A thru T, XII-D-183,
XII-D-184, XII-D-186, XII-D-141, XII-D-142, XII-D-143, XII-D-145, XII-D-146,
XII-D-148, XII-D-151, XII-D-152, XII-D-153, XII-D-155, XII-D-159, XII-D-161,
XII-D-162, XII-D-164, XII-D-165, XII-D-166, XII-D-167, XII-D-169, XII-D-172,
XII-D-174, XII-D-178, XII-D-179, XII-D-180, XII-D-186, XII-D-188, XII-D-189,
XII-D-190, XII-D-193, XII-D-194, XII-D-195, XII-D-196, XII-D-202, XII-D-213,
XII-D-214) found it wrong and/or unconstitutional to kill people through
exposures to hazardous air pollutants allowed by regulation.
Commenter XII-D-41 stated, in particular, that the Constitution does not
empower government with the perogative to cause human life to be taken at
random.
Response: The present state of scientific knowledge is such that "for a
carcinogen it should be assumed, in the absence of strong evidence to the
contrary, that there is no atmospheric concentration that, poses absolutely no
public health risk." 40 FR 59534 (1975). Therefore, the only way to
absolutely assure no risk of loss of human life due to benzene emissions
would be to ban alj_ emissions. However, the courts have considered this'
option and rejected it. In the Vinyl Chloride decision the D.C. Circuit
Court rejected the NRDC's argument that "the uncertainty about the effects of
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carcinogenic agents requires the Administrator to prohibit all emissions."
824 F.2d at 1147. Instead, the court stated that the Administrator's finding
of "safe" does not require zero risk, but rather an "acceptable" risk to
human health, considering what risks are "acceptable in the world in which we
live" 824 F.2d at 1165 (citing Industrial Union Deot.. AFL-CIO v. American
Petroleum Inst.. 448 U.S. 607, 642 (1980)). The regulations issued today
incorporate what the Administrator, exercising his discretion, has determined
to be an acceptable risk, within the meaning of the Vinvl Chloride decision.
Comment: One commenter (XII-D-24) stated that if, via the benzene rulemaking,
EPA is establishing a formal policy for rulemaking, then this establishment
of a generally applicable policy (such as those of Approaches B, C, and D)
without complying with the informal rulemaking process violates the concept
of administrative rulemaking. The commenter believed that Approach A is
consistent with accepted administrative rulemaking, because it allows
case-by-case decisionmaking.
Response: The EPA's proposed NESHAP for benzene, published July 28, 1988,
included four alternative approaches to regulation. The proposal of these
alternatives was a result of the Vinvl Chloride decision, which required some
revision to the EPA's approach to promulgating regulations under Section 112
of the CAA. All four options have now been subjected to public comment as
required by law, and EPA has responded to all significant comments, including
comments suggesting further alternative approaches. This process is in full
compliance with administrative rulemaking requirements. If, instead of
proposing four options, EPA had proposed any one of the four options, the
same administrative process would have been followed.
Any future Section 112 rulemaking actions will also be proposed for
public comment before being promulgated, and thus will comply fully with the
rulemaking requirements.
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3.0 ETHYLBENZENE/STYRENE (EB/S) PROCESS VENTS
3.1 EMISSION ESTIMATION
Comment: One private citizen (XII-D-04) questioned whether emissions from
leaks, spills, emergencies, startups, shutdowns and equipment malfunctions
were included in the calculation of 98 percent control efficiency for boilers,
flares and incinerators.
Response: The EPA's estimate of 135 Mg/yr (155 Mg/yr at proposal), from
process vent releases includes emissions from continuous operations, as well
as emissions from startup, shutdowns, and equipment malfunctions. These
emissions are residual from control devices or are uncontrolled intermittent
releases, such as emergency release vent emissions. Control devices and each
emission source used at each EB/S plant are documented in Appendix B of the
1984 withdrawal BID.1 The majority of vents (and emissions) at these
facilities are already vented to a combustion control device such as a
boiler, flare, or incinerator. For these types of combustion control devices,
98 percent control efficiency was assumed in calculating emissions. This is
the expected performance of a well designed and operated unit. Emissions
from EB/S process vents have been reduced by more than 98 percent from the
uncontrolled emission level. This estimate is considered to reflect all
process vent emissions aside from truly accidental releases. Emissions from
equipment leaks and accidents are not included in the emission estimate
because they are being addressed under other regulations. Equipment leaks
are regulated .by Subpart J of Part 61 of Title 40. Accidental releases are
subject to the accidental release regulations in the Superfund Amendments and
Reauthorization Act (SARA) Title III, Section 304.
3.2 DEMONSTRATION OF COMPLIANCE FOR STANDARDS PROPOSED UNDER APPROACH D
Comment: Two commenters (XII-D-104 and XII-D-220) requested that EPA extend
the time limit for the demonstration of compliance required by the standards
proposed under Approach D. One commenter (XII-D-104) stated that an emission
test to demonstrate compliance might itself require 90 days to complete, and
requested that the time limit on compliance reports be extended to 180 days.
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The second commenter (XII-D-220) felt that the 90-day compliance time
limit was inappropriate under Approach D, due to the extensive modifications
which would likely be required for an existing facility.
Response: Since no standard is being established, the commenters concerns
are no longer relevant. The EPA believes, however, that it would be useful
to clarify the compliance and reporting requirements to clearly distinguish
between these requirements. As required by the CAA and 40 CFR
Section 61.05(c), existing sources must comply with the standards within
90 days, unless they have received a waiver as provided for under 40 CFR
Section 61.11, or a Presidential waiver under Section 112(c)(2) of the CAA.
This requirement cannot be changed without an amendment to the CAA. Sources
that are unable to comply within the 90 days may apply for a waiver. Waivers
may be granted to extend the compliance time for a period not to exceed
2 years.
Reporting of the compliance demonstration is a separate requirement.
The EPA does recognize that where extensive emission testing is required,
more than 90 days may be necessary to conduct the tests, analyze the results,
and prepare the report. For this reason, reporting requirements in previous
rulemakings under Section 112 have ranged from 120 to 180 days.
3.3 WORDING OF STANDARDS PROPOSED UNDER APPROACH D
Comment; One commenter (XII-D-104) suggested that the proposed standards
should clarify which vents are to be controlled. He pointed out that there
are a number of minor vents from analyzers and other monitoring equipment
which have not required control. He advocated specifically exempting de
minimis releases from these vents.
Response: As no standard is being established for EB/S process vents, the
primary concerns of the commenters are no longer relevant. This comment does
indicate the term "process vent" can be subject to interpretation and there
may be confusion regarding the applicability of the decision to these minor
vents. The process vents of concern in this rulemaking were associated with
alkylation reactor sections, atmospheric or pressure columns, hydrogen
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separation systems and compressors. The vents of concern to the commenters
might be a type of a sample connection and as such would be subject to the
requirements of Subpart V of Title 40 Subpart 61.
Comment: Another commenter (XII-D-199) criticized the EPA's definition of
malfunction in the proposed EB/S standards. He stated that few upsets would
ever fit into the proposed definition, since in theory, any equipment break-
down would be preventable. He suggested the following revised definition of
malfunction:
"A failure of process or air pollution control equipment
caused entirely by design deficiencies, poor maintenance,
careless operation, or other reasonably preventable
equipment breakdown is not considered to be a malfunction."
Response: Since no standard is being established, the issue is no longer
relevant.
Comment: Commenter XII-D-247 suggested that instead of the new regulations
proposed, EPA should amend the existing benzene NESHAP Section 61.242-11 by
requiring all vents emitting over X Ibs/hr of benzene to be routed to a
95 percent efficient control device. The X should be set on a case-by-case
basis depending upon the emissions reduction needs at a particular plant.
The commenter also suggested that Section 61.246 (Recordkeeping) and
Section 61.247 (Reporting) of the equipment leaks standard should be revised
to include vents.
Response: The commenter's suggestion was an alternative to the standard
proposed under Approach D. Because under the final policy no standard is
being established, neither the proposed standards or this suggestion is
relevant. It should be noted, however, that the equipment leak standard is a
broad-based standard affecting any facility using benzene and is not an
appropriate place to address process vent emissions specific to EB/S plants.
3.4 REFERENCE
1. U. S. Environmental Protection Agency. Benzene Emissions from
Ethylbenzene/Styrene Plants - Background Information for Proposal to
Withdraw Proposed Standards. Environmental Protection Agency.
Publication No. EPA-450/3-84-003. Appendix B. March 1984.
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4.0 BENZENE STORAGE VESSELS
4.1 INTRODUCTION
Most of the comments on the benzene storage vessel source category came
from industry and focused on the proposed standards, especially those proposed
under policy Approach D. The comments are summarized below under sections
addressing the emission limit proposed under Approach D, cost estimation,
applicability of standards, wording of standards, and regulatory consistency.
4.2 THE EMISSION LIMIT PROPOSED UNDER APPROACH D
Comment; The CMA (XII-D-59) and its supporters (XII-D-29, XII-D-32, XII-D-36,
XII-D-98, XII-D-104, XII-D-197 and XII-D-199) noted that attempting to
achieve the 0.47 kilogram (kg)/day emission limit imposed by Approach D would
be costly and problematic, creating operating problems and safety hazards
disproportional to any marginal reduction in risk which might result. The
CMA representative stated that all new and existing storage vessels would
have to be modified to allow for the collection and routing of vapors to a
control device. He believed that most operators would seal the rim vents,
and then pad the enclosed vapor space with an inert gas to prevent the
possible accumulation of an explosive mixture. Closing the vessel would make
inspection of the floating roof more difficult, and the presence of inert gas
would make it more dangerous.
One commenter (XII-D-199) stated that a reduction beyond the 1 x 10"4
MIR in the storage category would require major changes in emission control
technology and redesign of vessels at his plant. He recognized that a
floating roof would have to be used and emissions collected and routed to a
flare, carbon canister, or incinerator. He indicated that at his facility
this would require replacement, not retrofitting, of the vessels. He
concluded by pointing out that the controls would have to be designed to
prevent safety problems such as flashback from combustion devices into the
vessel of flammable liquid or possible vessel rupture due to pressurization.
A terminal operator (XII-D-103) agreed, stating that public health and
safety must be protected, but not without considering the safety of employees
and equipment. He argued that safe and tested technology to achieve the
Approach D limits is not yet available.
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Using control techniques presently in use for most benzene storage
vessels, he estimated that to meet the emission limit proposed under
Approach D a plant would be limited to the use of a single 10,000-barrel
storage vessel equipped with a floating roof system such as described under
Approaches A, B, or C.
One commenter (XII-D-220) voiced concern about demonstrating compliance
to the standard proposed under Approach D, stating that the current, accepted
emission estimation techniques could only be used for existing control
techniques, and that even using the lowest available emission factors, a
facility with more than a few benzene vessels cannot demonstrate compliance.
Response: Because the emission limit under Approach D was not chosen as the
final standard, the commenters' concerns are now moot.
4.3 COST ESTIMATION
Comment: One commenter (XII-D-220) believes the cost of the standards
proposed under Approaches A, B, or C, could be significantly more than the
$100,000 per year estimated by EPA, because the wording of Section
61.271(a)(8) of the proposed regulation would require some vessels.to be
removed from service solely for retrofitting. He noted that in his 1981
comments on the standards proposed on December 19, 1980, he had estimated
degassing costs would be over $30,000 per vessel.
He stated that EPA also had not included the cost associated with the
loss of operating flexibility when a storage vessel is out of service, and
the potential additional costs due to the proposed inspection and repair
provisions, which could require removing vessels from service on an unplanned
basis.
Response; The EPA believes few, if any, plants would be required to degas
vessels to comply with the proposed Section 61.271(a)(8) [which is renumbered
in the final standards as Section 61.271(a)(4)] since this design specifica-
tion represents current industry practice (see comment and response in
Section 4.5 of this chapter). In addition, EPA expects that removal from
service and degassing of vessels for repair would occur infrequently. The
inspection and repair provisions referred to by the commenter are intended to
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detect major failures of the floating roof and seals, such as a sunken roof
or a gap in the seal. The EPA anticipates that such failures would not occur
at any one vessel or at several vessels at any one plant very often.
With regard to the cost of degassing, EPA reconsidered it after
evaluating the comments on the 1980 proposal for benzene storage vessels
(45 FR 835952). Additional vendor quotations were obtained, and the revised
formula and degassing costs were developed.1 Since neither the eommenter's
1981 submittal, nor the recent comment, specified the size of the vessel in
question, nor any additional information specific to his calculation, the
eommenter's cost estimate could not be specifically evaluated.
However, the EPA's revised estimates of the degassing costs, while
higher than those in the 1980 proposal, are generally substantially less than
the commenter's estimate of $30,000 per vessel. For example, if all seven of
the vessels in the large benzene production model plant were degassed (which
EPA believes would not be necessary to comply with the standards), the EPA's
estimated cost is $47,000 (1982 dollars). The corresponding annualized cost
over the 10-year period assumed for the rest of the equipment components is
estimated to be $7,600 (1982 dollars).2
In light of the expected infrequency of the events noted by the
commenter and the estimated cost of degassing, it is the EPA's engineering
judgment that these events would be unlikely to substantially increase the
nationwide annual costs of the standard.
Comment: Another commenter (XII-D-199 and XII-D-247) noted that although his
company is currently retrofitting two vessels with additional seals and/or an
IFR, an additional 4 tons per year (tpy) reduction at his plant would be
necessary in order to comply with the emission limit proposed under
Approach D. He projected the costs of routing storage vessel emissions to a
control device to meet the Approach D standard to be between $10,000,000 for
carbon canisters to $15,000,000 for using an existing flare system. He
noted that Approach D controls are expensive because they require a step-
change in control technology, with vessel replacement or rebuilding, rather
than retrofit.
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Response; Because Approach D was not chosen as the basis for the final rule,
this comment is not relevant to the final standards.
4.4 APPLICABILITY OF STANDARDS
Comment: A spokesman for the City of Saint Louis, Division of Air Pollution
Control (Docket No. A-80-14, Item XII-D-03), objected to the applicability of
the proposed NESHAP for benzene storage vessels under all approaches because
they exempt those vessels on trucks, rail cars, and barges of 10,000 gallons
or greater capacity. While acknowledging that the use of floating roofs on
such vessels is impractical, the Division said that provisions such as those
proposed under Approach C in Section 61.273 should apply, which allows the
use of alternative measures of emission control.
He stated that 11 rail tankers full of benzene arrive twice a week at a
facility in the city for transfer to barges, trucks, or a 900,000-gallon
storage vessel. Since the barges are on a navigable waterway, they are under
the jurisdiction of the Federal government. He stated that the Missouri
legislators have determined not to adopt regulations more stringent than
those that apply to other States, so that if the NESHAP exempts trucks, rail
cars, and barges, the State will not regulate them. The objection to the
exemption in the NESHAP was based on calculations by the Division showing
that transfer from the rail cars to barges emitted 114 tons of benzene in
1987. The Division felt this exposed the people in the vicinity of this
facility to excessive amounts of benzene.
Response: The control technologies that would be necessary to control
benzene emissions from storage vessels attached to mobile vehicles, such as
tankers, barges, or tank trucks, are different from those that are typical
for other storage vessels. Additionally, data collection on tankers, barges,
and tank trucks was not part of the surveys performed by EPA to develop a
data base to support the benzene storage vessel NESHAP. For these reasons,
it was never the intent of EPA to consider these types of benzene storage
vessels as designated sources under this NESHAP. Therefore, storage
vessels attached to mobile vehicles have been specifically excluded in
Section 61.270(d). This source category will be addressed separately as
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"benzene transfer operations," which is part of the EPA's response to the
court decision in Natural Resources Defense Council. Inc.. et. al v. U. S.
£P_A and American Petroleum Institute v. U. S. EPA (U.S. District Court,
District of Columbia, No. 83-2011 and 83-2951).
Comment: Another commenter (Docket No. A-80-14, Item XII-D-04) requested
clarification as to whether independent "for hire" storage vessels would be
subject to the proposed regulations. He felt that since these operations do
not process benzene, do not have any processing equipment, and are not
connected to any processing plants or refineries, EPA did not intend to
regulate them beyond the new source performance standards (NSPS) for storage
vessels. The commenter stated that storage terminals do not have the
constant throughput demand of a petrochemical plant or refinery and that
terminals average approximately 4.2 vessel throughputs per year. He stated
that the vessel and roof fitting loss calculations for storage-only vessels
would be 15 to 20 times smaller than those presented in the BID for the rules
proposed for benzene storage vessels in 1980. He also noted that the BID did
not consider that a public storage terminal would not benefit from a recovery
process like carbon absorption because it does not own the liquid recovered.
Response: The EPA has always clearly intended that the benzene storage
vessel NESHAP would apply to independent bulk storage terminals. These
independent terminals are similar to tank farms associated with refineries
and processing plants, which are also covered by the standard. A model plant
for these facilities was included in the technical analysis. This plant was
developed based on information provided in responses to Section 114 requests
in 1979; this information included responses from four public storage
facilities.
Only one of the responses from bulk storage facilities provided
information about the number of turnovers. The model plant assumes
9 turnovers, compared to the 4.2 turnovers reported by the commenter. The
EPA agrees that the working losses would be lower in vessels with a lower
number of turnovers. However, the lower number of turnovers would not affect
the breathing losses, which are a function of vessel size and diurnal
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temperature change. Furthermore, there may be other plant characteristics,
different from the EPA's model plant, that would tend to cause higher
emissions. For example, the model plant has only two vessels; in contrast,
EPA has information that at least one bulk storage facility recently had five
vessels storing benzene.
In the development of the NSPS for VOC emissions from volatile organic
liquid (VOL) storage vessels, EPA considered an exemption based on the number
of turnovers. The EPA found that the number of turnovers that any one vessel
undergoes in a year is neither constant, nor highly predictable at the time
of construction or retrofit. A standard designed to exempt vessels based on
low turnover rates would therefore be impractical from both the perspective
of enforcement and of compliance. The EPA concluded at that time that such
an exemption was not warranted.
4.5 WORDING OF STANDARDS
Comment: One commenter (XII-D-34) stated that the American Society of
Testing and Materials (ASTM) had changed the wording for "Nitration Grade
Benzene" and suggested that the wording of 40 CFR 61.270(a) be changed to be
consistent with the revised wording.
Response: The EPA agrees with the commenter that the wording of
Section 61.270 (a) should be changed. Section 61.270(a) has been revised to
specify:
Industrial Grade Benzene
Refined Benzene-485
Refined Benzene-535
Refined Benzene-545
ASTM D 836-84
ASTM D 835-85
ASTM D 2359-85a
ASTM D 4734-87
The above specifications represent the ASTM specification for various grades
of benzene and are consistent with the grades EPA intended to regulate under
these standards.
Comment; One commenter (XII-D-220) noted that with the exception of
Section 61.271(a)(8) of the proposed regulation, all other requirements for
vessels with internal floating roofs (IFR's) under Section 6T.271(a) allow
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retrofits to take place the first time the vessel is emptied and degassed or
10 years from the date of promulgation, whichever comes first. As stated in
the proposal for Approaches A, B, and C, Section 61.271(a)(8), which requires
retrofitting of vessel openings to extend below the liquid surface, does not
include this time provision. The commenter recommended that the compliance
schedule for paragraph (a)(8) be rewritten similar to that in
Sections 61.271(a)(4) and (5) of the regulation proposed under Approaches A,
B, and C.
Response: This provision, in Section 61.271(a)(4) of the final standards,
has not been changed. The API publication, "Evaporation Loss from Internal
Floating-Roof Tanks," presents general descriptions of the components in use
for IFR vessels (Docket No. A-80-14, Item IV-H-4). This publication describes
two basic designs including noncontact floating roof decks, and both of these
designs are provided with projections that extend below the liquid surface
wherever penetrations occur in the deck. The 2519 test series upon which the
emission factors for these vessels are based used a noncontact IFR with such
projections as well. The EPA considers the noncontact deck provided with
projections extending below the liquid surface at each opening to be the
typical configuration. The intent of this requirement in the regulation is
to ensure that vessels with noncontact IFR's conform with the typical
baseline level of control. Therefore, it is unnecessary and unreasonable to
allow a delay in compliance with this requirement,
4.6 REGULATORY CONSISTENCY
Comment; Several commenters were concerned that the final NESHAP should be
consistent with the benzene storage vessel NSPS to which they are already
subject. The CMA (XII-D-59) and its supporters and Commenter XII-D-34
advocated that the reporting and recordkeeping requirements of the new
benzene storage vessels should be consistent with those requirements for VOL
storage vessels under 40 CFR 60 Subpart Kb.
Another commenter (XII-D-199 and XII-D-247) proposed that EPA should
make the benzene regulations as consistent with other regulations as possible
in order to eliminate confusion and promote better compliance. He recommended
that EPA adopt the NSPS requirements for storage vessels in Subpart Kb
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directly, since the proposed regulations for benzene vessels are so close
already for seals and floating roofs. Commenter XII-D-247 suggested that
this could be accomplished by adding a sentence to the existing benzene
NESHAP (for equipment leaks) requiring all vessels to comply with Subpart Kb
and by revising Sections 61.246 (Recordkeeping) and 61.247 (Reporting) of the
equipment leaks standards to include vessels.
Response: The differences in the statutory requirements of Sections 111 and
112 of the CAA may result in different standards for emission sources that
are similar. As the commenters noted, the control level that was proposed as
an ample margin of safety under Approaches A, B, and C is based on control
equipment similar to that in the NSPS for VOL storage vessels (40 CFR 60
Subpart Kb). Consequently, where appropriate, EPA made the wording of the
requirements similar between Part 61 Subpart Y and Part 60 Subpart Kb.
However, there are also appropriate differences, such as control requirements
for existing as well as for new benzene storage vessels.
Comment; One commenter (XII-D-34) noted that the proposed standards permits
an owner up to 10 years to install additional seals as controls, but only
allows 60 days to fix a defective seal should it not pass the required yearly
inspection. He viewed this as inconsistent and recommended that the repair
be extended up to 18 months if immediate repair is not feasible. He asked
EPA to consider, when setting the time period, that emptying the vessel and
loading other vessels with the product would also create emissions. Another
commenter (XII-D-104) advocated that EPA clarify compliance requirements to
allow for repair of damaged seals without the facility being out of
compliance.
Response; The inspections to which the first commenter (XII-D-34) referred
are annual visual inspections from outside the vessel. These inspections
would detect failures of the floating roof, such as a sunken roof or gaps in
the seal. Such failures prohibit the roof from functioning as intended,
until repair is made. The final standards (those proposed under
Approaches A, B, and C) require that all existing fixed roof vessels be
equipped with IFR's with continuous seals within 90 days of the effective
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date of the standards, unless a waiver of compliance has been granted. The
EPA judged that it is reasonable to repair failures of these IFR's shortly
after they are detected, rather than allowing the condition warranting repair
to continue until the next scheduled degassing, or a period of up to
18 months, as suggested by the commenter.
However, EPA considered a 45-day (rather than the 30 days allowed by the
standards proposed under Approaches A, B, and C) repair period, with a 30-day
extension possible; the 45-day period would be consistent with the NSPS for
VOL storage vessels (40 CFR 60 Subpart Kb). The reason that 40 CFR 60
Subpart Kb has a 45-day (versus 30-day) repair period is that in the event
that special materials not normally kept in stock by suppliers were needed
(such as Teflon*1 seals), 30 days would probably be insufficient for repair of
this equipment. ' The same situation would exist for vessels subject to the
benzene rule. Therefore, EPA determined that it was reasonable to make this
rule consistent with Subpart Kb. A 30-day extension may still be requested
if repairs are likely to exceed the initial 45-day repair period. Facilities
would not be out of compliance as long as repairs were completed within these
time periods.
The requirements to add certain pieces of equipment at the first
degassing was part of the option chosen by the Administrator to be proposed
under Approaches A, B, and C and to provide an ample margin of safety for the
final rule. The option was based on a grouping of controls that achieve
similar emission reductions on a typical vessel given the costs of achieving
them. The largest emission reductions are achieved with all fixed roof
vessels having IFR's with continuous seals, and with retrofitting
liquid-mounted primary seals and secondary seals on existing EFR vessels
having vapor-mounted primary seals. These are required within 90 days of the
effective date unless a waiver of compliance of up to 2 years has been
granted. Smaller emission reductions are estimated to be achieved by the
equipment that is not required until the first degassing (i.e., the cost of
degassing would not be incurred only to add this equipment). This equipment
is the addition of gasketed fittings on continuous IFR's that were in place
before the effective date of the standards, and the addition of secondary
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seals on external floating roofs (EFR's) that were equipped with the best
type of primary seals (i.e., liquid-mounted primary seals) before the
effective date of the standards.
4.7 REFERENCES
1. Memorandum from Pelland, Alice, Radian Corporation, to Benzene Docket.
May 24, 1988. Cost Analysis for Control of Benzene Emissions from
Benzene Storage Tanks. Docket No. A-80-14, Item No. X-A-1.
2. Reference 1.
3. U. S. Environmental Protection Agency. Benzene Emissions from Benzene
Storage Tanks - Background Information Document. Publication
No. EPA-450/3-80-034a. Research Triangle Park, NC. December 1980.
4. Letter from Adamsky, Brian K., Unitank Terminal Service, to
Hyunh, Thomas, Air Management Services, City of Philadelphia. June 12,
1987. Attachment (3) to: Motion for Partial Summary Judgment and
Schedule of Attachments. Civil Action No. 87-6793, U.S. District Court
for the Eastern District of Pennsylvania. United States of America,
Plantiff, v. Unitank Terminal Service, et. al.. Defendants. March 1989.
5. U. S. Environmental Protection Agency. VOC Emissions from Volatile
Organic Liquid Storage Tanks - Background Information for Promulgated
Standards. Publication No. EPA-450/3-81-003b. Research Triangle
Park, NC. January 1987.
6. Telecon. Taylor, D., Midwest Research Institute, with 01 sen, K., High
Rise Services Corp. December 13, 1984. Inspection procedures for
storage vessels.
7. Telecon. Friedman, E. M., Midwest Research Institute, with Ferry, R.,
Conservatek, Inc. December 11, 1984. Supply constraints for storage
vessel repairs.
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5.0 EQUIPMENT LEAKS
5.1 INTRODUCTION
Most of the commenters who expressed views on the equipment leaks source
category were representatives of industries who were concerned about how the
proposed standards under Approach C or D would affect them, or who raised
technical points about complying with either of these emission limitations.
The comments discussed here concern control technologies, emissions
estimates, cost estimates, demonstration of compliance, and specific points
about the wording of the proposed benzene equipment leaks standard.
5.2 CONTROL TECHNOLOGIES
Several commenters discussed control technologies for pumps, flanges and
valves, general availability of controls, and whether these technologies
would enable facilities with equipment leaks to achieve compliance with the
proposed standards under Approach C or D.
General Feasibility of Approach C or D Standards
Comment: Commenters XII-D-220, XII-D-247, and Docket No. A-79-27,
Item IX-D-13, pointed out that standards proposed under Approaches C and D
essentially put a cap on the maximum number of various pieces of equipment
that could be present at a facility if the facility were not to exceed the
emissions limit. Commenter XII-D-220 used the EPA stratified emission
factors for equipment screening between 0 and 1,000 parts per million (ppm),
the lowest generally accepted emission factors, to show that a facility could
only have 20 valves, or 2 pumps, or 291 flanges before the proposed
0.14 kg/day limit of Approach D was exceeded. Commenter A-79-27, IX-D-13
stated that using the average emission factor for light liquid valves to
calculate emissions, a plant could have no more than 82 light liquid valves
without exceeding the proposed Approach C emission limit, and no more than
1 light liquid valve without exceeding the proposed Approach D emission
limit.
Commenter XII-D-59 pointed out that even at a chemical facility where
emissions from relief valves are routed to a flare system, where leakless
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pump technology is used, and where all open-ended lines are capped, the EPA's
emission factor methodology was found to produce emissions estimates far in
excess of even Approach C's 14 kg/day limit. Another commenter (XII-D-255)
reported that site-by-site estimates of total air emissions indicates that
none of its five facilities are below the 14 kg/day emission limit of
Approach C and that most of the emissions are from equipment containing less
than 10 percent benzene.
Commenter XII-D-199 stated that fugitive emissions could not be reduced
significantly without the development of new technology. The commenter
stated that even using the EPA's correlation curve method for calculation of
emissions from his facility's 9,500 equipment components, their current
emissions were 20 times higher than what would be allowed under the proposed
Approach D limits. Such a major step change in emissions could not,
according to the commenter, be achieved with any of the currently available
control technologies. The commenter went on to discuss controls for specific
equipment types.
Commenter XII-D-199 (and XII-D-247) estimated that emissions from 44 out
of 46 pumps at his company could be reduced by a total of 0.2 to 0.3 tons/year
by installation of either pumps with dual mechanical seals with barrier fluid
or canned pumps (see Docket No. A-79-27, Item IX-E-6). The commenter con-
sidered dual mechanical seals to be a demonstrated technology, but stated
that canned pumps have not been demonstrated for his company's EB/S unit's
size and horsepower. Therefore, the commenter would expect problems in
installing, operating and maintaining canned pumps. The other two pumps in
the commenter's company are in corrosive service; the commenter did not know
of any existing dual mechanical seal or canned pump designs which could
withstand such conditions.
Commenter XII-D-199 stated that there is no known available technology
to reduce flange emissions. The commenter discussed three theoretical
methods to reduce flange emissions: routing to control devices, replacing
the gasket material, and welding all flanges. The commenter stated that for
his company's 7,000 separate flanges, routing to a control device would
Involve installing miles of piping and ensuring that there were no leaks from
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the piping or from leak capture devices. The commenter eliminated gasket
material replacement as a possibility, since his company knew of no available
nonleak material. The commenter further stated that the final choice,
elimination of all flanges, was not practical because it would make it
difficult to isolate and evacuate equipment so that maintenance could be
performed safely. Even if some flanges could be eliminated, it would not be
enough to reduce emissions to target levels.
Commenter XII-D-199 stated that his company has approximately
2,500 valves, many in processes that are corrosive in nature. The company
had considered replacement with pinch and bellows valves, but did not feel
that these technologies were readily available and demonstrated for their
type of service. The commenter stated that a 3- to 4-year demonstration
period would be needed to evaluate equipment failure rates before there could
be any large scale use of these valves.
The commenter concluded that the lack of demonstrated technology to
control valve and flange emissions would contribute to his facility's
inability to meet the proposed Approach C and D limits.
Response: The EPA understood at the time of proposal that the proposed
Approaches C and D equipment leaks emission limits would require performance
beyond that which is achievable (or demonstrable) with existing technology
and would limit the number of components at a facility. It is for this
reason that EPA concluded that widespread closure could result from these
standards should they be promulgated. Since the final decision does not
implement one of these proposed emission limits, these issues are no longer
relevant. Consequently, responses are not provided on these issues.
Feasibility for Pumps
Comment: Commenter XII-D-220 stated that a study of his company's
maintenance records shows that dual mechanical seals on pumps last an average
of only 8 months, versus 2 years for single mechanical seals. The commenter
pointed out that shutdowns or upsets due to seal failures can, along with
taking a pump out of service, lead to significant emissions; thus, net VOC
emissions may actually be higher with dual mechanical seal pumps. The
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commenter suggested that EPA consider this issue when setting equipment leaks
standards. The commenter wrote that his company was recommending that
improved single seal designs be used on all their new installations.
Response: The specific issues regarding seal life and overall VOC reduction
have not been investigated since EPA has not required sources to use dual
mechanical seals on pumps. That is, because operating conditions in a given
process determine the applicability and life of equipment, the existing
standards for equipment leaks do allow the owner or operator of each source
to determine for itself the best means of complying with the standards. In
addition, neither of the standards proposed under Approach C or D required
use of specific equipment.
Feasibility for Valves
Comment; One commenter (XII-F-17 and XII-D-198), an equipment vendor,
described the development by his company of a bellows sealing mechanism which
provides for hermetic sealing of rotary (quarter-turn) valves. The commenter
stated that the current bellows design available from his company can be
applied to typical ball and plug valves through 6 inches in size and butterfly
valves through 12 inches in size, and that the technology is suitable for any
rotary ball, plug, or butterfly valve. It can be applied to rotary motion of
Up to 360°. The commenter also stated that all wetted parts are of corrosion
resistant materials, and that the design can satisfy the full pressure range
for either Class 150-225 pounds per square inch (psi) or Class 300-720 psi
service.
The commenter wrote that a stainless steel housing surrounding the
bellows assembly provides, among other things, protection from external
mechanical or chemical attack, and a backup sealing capability in the event
of a bellows leak. The commenter acknowledged however, that an optimum
solution to this and other problems has not yet been devised.
The commenter indicated that this'technology has been used in berated
water systems since the early 1960's, and testing of the original bellows
seal concept and subsequent improvements have been conducted over the past
8 years. The commenter wrote that field trial units are currently underway
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in a wide range of specific applications including phosgene, hydrogen,
benzene, chlorine, ammonia, uranium hexafluoride (UF6), and high-purity
fluids.
The commenter indicated that this technology is capable of achieving
valve leakage rates below 1 x 10"8. Overall, the commenter estimated that
the technology applied to about 80 to 85 percent of the process valves in a
typical piping system. For a typical $100 million facility, the commenter
predicted that this technology could be installed at an additional cost of
about 1 percent of capital costs or less..
Comment: Commenter XII-D-59 and XII-D-248 rebutted the presentation of
Commenter XII-F-17, stating that sealed bellows valves, while useful in some
situations, were not an acceptable control technology for all situations.
Commenter XII-D-248 noted that bellows valves have limited applicability
because they are not available in all materials, cannot be used in some high
pressure applications, and are not suitable for fluids that may polymerize
and restrict the movement of the bellows. Further, they are not generally
available for process lines over nominal pipe sizes 6 for gate valves and 8
for globe valves, and only one manufacturer has a bellows seal that can be
used on quarter-turn valves. The commenter also said that the lifetime of
bellows equipment is unknown. He said a survey of plants showed that, for a
3-year period of use, reported failures ranged from 0 to 30 percent. The
commenter also said there is a,potential for high emissions when bellows
valves fail. These valves still require a packing gland. The commenter said
that if plants neglect packing maintenance, a catastrophic failure of the
bellows may result; but if maintenance is good, plants may not detect the
failure of the bellows. In the opinion of the commenter, valves without
bellows seals already provide good service.
Response: Information available to EPA continues to support the conclusion
that while sealed bellows valves are useful in some situations, they are not
universally applicable and thus will not eliminate all benzene emissions from
valves (Docket No. A-79-27, Item VII-A-2). Some of the considerations which
have limited the applicability of sealed bellows valves are variability of
5-5
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service life, corrosion and mechanical failure in service with many
chemicals, significant emissions when the bellows fail, and limits on
pressure and temperature of service streams. The availability of alternative
and equivalent performance systems demonstrates the advantage of standards
which do not prescribe specific control equipment but instead give emission
or performance levels which sources can achieve using any means available.
Other Comments
Comment: Commenter XII-D-220 advocated that equipment be considered
"available" only after it has received adequate field trials and all aspects
of the equipment operation have been properly evaluated.
One commenter (XII-D-199 and XII-D-247) emphasized that equipment
controls instituted to attempt to meet Approaches C and D levels carried
their own safety and environmental risks. The installation of new equipment
could cause increased emissions at that time, and could also decrease safety
thereby increasing risks for plant personnel and the community.
Response: In keeping with the Vinyl Chloride decision, the criterion of
availability of technology cannot be considered in a NESHAP rulemaking
decision unless it is considered in the ample margin of safety step.
Because neither EPA nor the commenter identified any equipment or
control measures to achieve these proposed standards, EPA cannot evaluate
safety issues connected with controls. Since EPA cannot know the details of
the operating conditions at each individual plant, it is up to the owner or
operator of each plant to evaluate such issues.
5.3 EMISSIONS ESTIMATION
Several commenters felt that EPA had substantially overestimated
emissions from equipment leaks. Three commenters discussed what they saw as
flaws in the emissions estimation methodology. Two other commenters dis-
cussed measured or predicted ambient air benzene concentrations which were
significantly lower than the EPA's prediction as indicating that emissions
were overestimated.
5-6
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Emissions Estimation Methodology
Comment: Commenter XII-D-32 stated that the conventional synthetic organic
chemical manufacturing industry (SOCMI) factors, developed from refinery data
where the key issue was flammability of chemicals, were not appropriate for
facilities that had to comply with the low Occupational Safety and Health
Administration (OSHA) exposure limits presently in force for toxic chemicals
such as benzene. The commenter attached several papers in support of the
point that facilities handling toxic chemicals and facing low OSHA limits had
emission factors lower than the SOCMI factors.
Commenter XII-D-59 (the CMA) and their supporters believed the estimated
total benzene emissions of 2,500 Mg/yr to be substantially overstated" for
three reasons: (1) the estimate assumed a higher percentage of leaking
components than is actually found in the chemical industry, (2) the estimate
assumed higher emission rates for both leaking and nonleaking components than
are actually found in the chemical industry, and (3) the estimate does not
accurately reflect the extent to which effective control components are used
in the chemical industry. The commenter referenced several studies in
support of these points. Three of these studies, including one with bagging
data, pointed to the conclusion that the percentage of components screening
as zero in chemical facilities is higher than the maximum percentage implied
in the screening value distributions used to develop the EPA's "leak/no leak"
factors. The CMA argued that EPA should have developed more realistic
estimates of benzene emissions.
One commenter (Docket No. A-79-27, Item IX-D-04) stated that the
emissions data and information in "Benzene Fugitive Emissions -- Background
Information for Promulgated Standards", EPA-450/3-8-032b, was in some cases
wrong or highly suspect and contributed to overconservative emission
estimates. The commenter pointed out that Table C-2 in this document showed
Plant Number 75 as having benzene emissions of 1.92 g/sec from sources
subject to the original benzene NESHAP; however, the commenter's company is
confident that those emissions are actually less than 0.71 g/sec.
Response; In the July 28, 1988, notice (53 FR 28496) EPA discussed many of
the same concerns expressed by the commenters and indicated that this
5-7
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overstatement of emissions was a consideration in the proposed decision under
Approach A. No quantitative estimates of the overstatement, or the bias,
were presented at proposal because of the limited data available. Moreover,
better estimates could not be developed because an industry-wide study of the
necessary scope could not be conducted within the 180-day period allowed by
the court order for proposal.
Since proposal, EPA has further considered whether a better estimate of
emissions or an estimate of the likely bias could be made. In this, EPA
recognized that complete resolution of the issues would require a major
research effort including extensive mass emission measurements for components
screening at 0 to 200 ppm. Such a fundamental assessment was not feasible in
the year between proposal and promulgation. Consequently, efforts were
directed at developing an estimate of the expected bias. This was evaluated
using information from compliance reports and emission studies of units
handling air toxics. The specific information obtained and considered is
summarized below.
To consider a representative sample of current performance from
compliance reports, EPA randomly selected a sample of 25 facilities in Texas
subject to the benzene NESHAP, many of them large plants and some with more
than 1,000 pieces of equipment. This sample included roughly equal numbers
of refinery and SOCMI facilities. Next, the most recent year's worth of
self-monitoring records were obtained for as many facilities in the sample as
time would allow. Almost all of these data are for 1987 and 1988 and the
data are presumed to reflect the current status of equipment leak emissions
control. From the monthly values reported for the number of pumps and valves
found to be leaking, the average percentage leakers rates for pumps and
valves were calculated for each plant.
In addition, self-monitoring reports for 11 facilities in Louisiana were
provided by State Office of Air Quality officials, and were selected at
random from readily available files of facilities required to report
emissions of hazardous air pollutants. Almost all of these facilities were
SOCMI plants. Average percentage leaker rates for pumps and valves were also
calculated for these plants.
5-8
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Many of these units had no leaking pumps or valves (i.e., a leak
frequency of 0.0 percent), and the average leak frequencies were 0.27 percent
for valves and 2.3 percent for pumps (see Docket No. A-79-27, Item IX-B-5).
As shown in Table 5-1, these leak frequencies are comparable to the leak
frequencies reported for a survey of facilities that was submitted by CMA
(Docket No. A-79-27, Item IX-D-08). These leak frequencies are lower than
the average expected leak rates of 3 to 5 percent for valves and roughly
10 percent for pumps.
In addition to the compliance reports for facilities subject to the
existing NESHAP, EPA also reviewed a limited amount of more comprehensive
data for several process units with equipment in benzene service. The
derived component average emission rates for these units are summarized in
Table 5-2. For these units, the measured concentrations showed emission
rates that were up to'20 to 30 times lower than would be predicted using the
EPA's estimation procedures.
Data for other air toxics show a similar pattern. Specifically, recent
comprehensive studies on process units handling butadiene or ethylene oxide
indicate average leak frequencies of 0 to 5 percent and emission rates that
are a factor of 5 to 20, or more, lower than the EPA's estimates. These data
were obtained from 12 butadiene and 10 ethylene oxide producers using a joint
EPA-CMA protocol for the data collection. These data are one of the more
comprehensive sets available and are considered to be representative of
facilities handling these compounds. Table 5-3 compares the derived average
emission factors for ethylene oxide and butadiene with average refinery
factors and with the derived estimates for one benzene unit.
Based on this information, and the information from the Subpart J
compliance reports, EPA concluded that control levels being achieved are
significantly better than originally predicted. Based on limited
comprehensive data for benzene process units and the comprehensive data for
other air toxics, benzene equipment leak emissions may be overstated by a
factor of 5 to 20.
Although this information provides an indication of the magnitude of the
bias in the emission estimates, it is not a sufficient basis for actually
developing new emission factors that would be generally applicable to all
5-9
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TABLE 5-1. A COMPARISON OF LEAK RATES BY COMPONENT FOR SUBPART J
MONITORING REPORTS AND CMA SURVEY DATA
Component
Subpart J
Monitoring Reports
CMA Member Survey
Valves, gas
(range)
liquid
(range)
Pumps
(range)
Pressure relief valves,
gas
light liquid
0.27%a
(0 - 1.3%)
0.27%a
(0 - 1.3%)
2.27%
(0 - 12.5%)
>*«
NA
NA
0.37%
(0 - 4.0%)
0.49%
(0 - 4.0%)
2.7%
(0 - 25%)
1.2%
0.85%
Flanges
NA
0.036%
Compliance reports do not distinguish between service types for valves.
NA - not available. Compliance reports do not include survey of pressure
relief valves or flanges.
5-10
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facilities. This occurs because leak frequency and the associated emission
rates vary widely among facilities and are believed to be a function of
original design, age of the process unit, equipment used, quality of the
maintenance, and motivation. Development of less biased emission estimates
requires information that is not available at this time and that can only be
obtained through an extensive study of the industry. Consequently, EPA has
not yet been able to develop better estimates and the emission estimates
remain as presented in the proposal notice. However, EPA has begun compiling
a data base for equipment component screening and bagging data of sufficient
quality to develop revised emission factors and leak rate/screening value
correlations.
In response to Commenter Docket No. A-79-27, Item IX-D-04, EPA would
like to point out that the Table C-2 of the final BID to which the commenter
referred gives pre-NESHAP baseline emissions estimates. For the emissions
and risk assessment for the current rulemaking, EPA assumed emission rates
which reflected the level of control projected to have been achieved under
the existing NESHAP. For Plant Number 75, this post-NESHAP emission rate was
0.68 g/sec, which is slightly less than the 0.71 g/sec cited by the
commenter.
Modeled and Monitored Ambient Concentrations
Comment: One commenter (Docket No. A-79-27, Item IX-D-04) pointed out that
Table C-2 shows a predicted maximum annual average benzene concentration of
25 micrograms per cubic meter (ug/m ) in the vicinity of Plant Number 105.
The commenter stated that a study done by the Texas State Air Control Board
and based on actual monitoring data, showed the average benzene concentration
in the vicinity of that plant to be 6 ug/m3. The commenter also cited other
data from the same study which showed that the annual average ambient benzene
concentration in one city with many benzene sources ranges from 4 to 20 ug/m ,
and that similar concentrations were measured in another city with no
significant stationary sources of benzene.
Response: The concentration of 25 ug/m3 for Plant Number 105 which the
commenter cited was the maximum annual average benzene concentration for
5-13
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baseline emissions before the benzene NESHAP was promulgated. The modeled
maximum annual average benzene concentration for Plant Number 105 under the
current NESHAP is 7.3 ug/m3; this is the value with which the commenter
should be making comparisons.
The EPA obtained a copy of the ambient monitoring report to which the
commenter referred. Included in this report was information on the precision
and accuracy of the monitoring results. The EPA feels that the comparison of
the 7.3 ug/m predicted by the EPA's Human Exposure Model (HEM) to the
6 ug/m calculated from study data for the vicinity of this particular plant
shows the two values are in agreement given the range of uncertainty of the
model, uncertainties in the emissions estimates, and the uncertainties in the
analysis of the ambient monitoring samples.
Comment: One commenter (XII-D-199) compared the EPA's typical predicted
fugitive emission impacts of 24 parts per billion (ppb) with the 4.3 ppb
fence!ine emission level which his company had modeled based on their emission
estimate for equipment leaks. The commenter further stated that after his
company finished storage vessel modifications, their emissions would yield a
fence!ine concentration of 1.3 ppb. The commenter pointed out that his plant
was older than most in the industry and their fenceline was close to their
neighbors. Furthermore, the commenter compared the 1.3 ppb to typical
background concentrations of 5 to 6 ppb. The commenter believed that the
EPA's analysis would result in requiring controls when risks were actually
already at an acceptable level.
Response; The EPA contacted the commenter to determine the basis for the
conclusion that typical modeled maximum concentrations were 24 ppb (Docket
No. A-79-27, Item IX-E-9). The commenter calculated the 24 ppb concentration
by dividing the 6 x 10"4 MIR given for equipment leaks in Table IV-2,
53 FR 28510 of the preamble, by the unit risk factor of 0.026/ppm cited in
the preamble.
According to the EPA's modeling results and calculations for the
commenter's specific facility, the maximum benzene concentration predicted
for that facility under the existing NESHAP would be approximately 27.3 ug/m3,
5-14
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or 8.5 ppb. The difference between this 8.5 ppb and the 4.3 ppb modeled by
the commenter is within the uncertainty ranges of the emission estimates and
differences among dispersion models.
Comment: One commenter (XII-D-255) reported that benzene concentrations (of
1 to 3 ppb) measured at the fence!ine at five facilities are an order of
magnitude less than those EPA apparently used in the risk estimate.
Response: Information provided by the commenter regarding the benzene
concentrations and the conditions under which they were measured is
insufficient to evaluate the comparison. Without knowing such information as
the wind direction and speed, the monitoring method, whether the concentra-
tions were annual averages or represent grab samples, it is impossible to
compare the annual average concentrations modeled by EPA to the concentrations
cited by the commenter. However, agreement to within an order of magnitude
is well within the uncertainty of the estimates.
5.4 PLANT LOCATIONS USED IN RISK ESTIMATION
Comment: Commenter XII-D-253 (API) reviewed the plant locations used by EPA
in risk modeling for equipment leaks. They stated that the latitude and
longitude used for 65 of the 131 equipment leaks sources were in error and
provided new coordinates for 55 of these emission sources. Copies of United
States Geological Survey (USGS) maps showing the plant locations were also
submitted. The commenter claimed that the errors in plant location could
lead to drastic changes in estimates of risks, particularly MIR. The
commenter also used the maps to identify the distance from the emission
source to the closest residence, and found that for many plants, the distance
was greater than assumed by the HEM. The commenter thought that this could
also cause overestimation of MIR.
Response: The EPA has rerun the HEM using the API's coordinates to consider
the effect of facility location on estimated MIR, incidence, and risk
distribution. The revised analysis used the facility locations provided by
the commenter for 55 of the 131 plants. The EPA spot checked some of these
latitudes and longitudes against USGS maps provided by the commenter to
verify that the coordinates were reasonable, and corrected one error found.
5-15
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The EPA also calculated coordinates for 10 plants that the commenter indicated
were in error but did not provide new coordinates. Finally, the locations of
the other 65 plants were also reviewed, and several corrections were made.
In particular, locations assigned to some facilities had been inadvertently
switched in the previous model run. Also, seven plants which are known to be
closed or no longer use benzene were deleted.
The revised risk estimates are located in Docket No. A-79-27,
Item IX-B-1. A comparison of the revised results with the previous HEM run
(Table 5-4) shows that there is no change in the overall MIR or incidence for
the equipment leak source category. Changes in the risk distribution are
also negligible. Although the locations of 77 plants changed, MIR increased
or decreased for only 30 individual plants. The magnitude of the change
varied from about 2 percent for some plants to over three orders of magnitude
(a thousand-fold change) for two plants. The change in MIR for 20 of the
30 plants was less than one order of magnitude. Those plants where the MIR
changed drastically were plants that had clearly been mislocated in the
previous analysis (e.g., in a bay), and the large change is reasonable.
However, as previously noted, these changes at individual plants do not
change the risk estimates for the source category as a whole.
The response to the commenter's points about the distance from emission
sources to the nearest residences is contained in Chapter 7.0 with other
comments on exposure modeling procedures.
5.5 COST ESTIMATION
Comment: Commenter XII-D-28 challenged the EPA's estimated costs for Option 1
controls (sealed bellows valves and dual mechanical seals on pumps) for
equipment leaks at petroleum refineries. The commenter said that the EPA
estimate averages to about $400,000 per facility. For one of his facilities,
the commenter had conducted an engineering evaluation showing costs of about
$1,250,000, or more than three times as great as the EPA estimates.
Response: To clarify the commenter's estimate of $1,250,000, EPA contacted
the commenter for a breakdown of the costs that were included in the
5-16
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TABLE 5-4. RISK3 ESTIMATIONS USING REVISED PLANT LOCATIONS
Risk Estimate
Using Revised
Plant Locations
Proposal Risk
Estimate for NESHAP
Incidence (case/year)
MIR
Risk distribution, >
cumulative >
(persons) ' _
(modeled to 50 km) >
10'
10"
>1 x 10
x 10
-5
>1 x 10 °
Total Modeled
0.2
6 x 10"4
0
0
2,000
50,000
1,000,000
200,000,000
0.2
6 x 10"4
0
0
3,000
60,000
1,000,000
200,000,000
Incidence for
each risk group,
noncumulative
(case/year)
>1 x 10"?
>1 x 10"i
>1 x 10"J
>1 x 10"r
>1 x 10~£
<1 x 10"5
0
0
0.005
0.01
0.04
0.2
0
0
0.007
0.02
0.04
0.2
All risk estimates are rounded to one significant figure. Due to
independent rounding, figures given in the table for risk group incidence
may not sum to the value given for total incidence.
The estimated number of people exposed to ambient concentrations resulting
in predicted individual risk levels above the level shown. Population is
cumulative (e.g., at baseline 1,000,000 people are exposed to risks greater
than or equal to 1 in 1,000,000).
Risks were calculated on a pi ant-by-plant basis and summed. Persons exposed
to emissions from more than one plant were counted for each plant's impact.
This is the estimated annual number of cases of leukemia for the population
exposed to each risk level. It is not cumulative (e.g., at baseline there
would be 0.04 case/year in the population exposed to risk levels greater
than or equal to 1 in 1,000,000 but less than 1 in 100,000).
5-17
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calculation of this number (Docket No. A-79-27, Item IX-E-5). According to
the commenter, the calculation included only replacement of all valves by
seal!ess valves, as the facility in question had already vented all tandem
seal pumps to flares. The commenter provided a detailed list of the number,
size, and current supplier-quoted costs for the valves which would be
replaced. The commenter also included a labor cost for installation, and the
cost of a piping system.
According to the commenter, the $1,250,000 was a one-time capital cost.
Since EPA costs for equipment leaks controls presented in the preamble were
all amortized costs expressed in 1979 dollars, it was necessary to convert
any costs quoted by commenters to the same basis. Thus, in order to compare
the $1,250,000 with the EPA cost figures for Option 1 controls, this valve
replacement cost was converted to May 1979 dollars and amortized over 10 years
at an interest rate of 10 percent (Docket No. A-79-27, Item IX-B-2). After
adjustment, the $1,250,000 became an annualized cost of $139,000 in 1979
dollars. This is less than the average EPA estimate of $400,000 to which the
commenter compared his estimated cost for his facility.
Comment: Commenter XII-D-199 estimated that to replace 44 of the 46 pumps at
his facility in order to reduce emissions, it would cost from $4,000,000
(pumps with double seals with barrier fluid) to $15,000,000 (canned pumps).
Response: To clarify the commenter's estimate of $4 to $15 million, EPA
contacted the commenter for a breakdown of the costs that were included in
the calculation of these numbers (Docket No. A-79-27, Item IX-E-9). The
commenter did not give a breakdown of what was included in these costs, but
did say that they were total installed capital costs in 1988 dollars.
In order to compare these values to the EPA costs for pumps, they were
converted to 1979 dollars and amortized over 2 years at a 10-percent interest
rate (Docket No. A-79-27, Item IX-B-3). After adjustment, the $4 to
$15 million becomes an annualized cost of $1,380,000 to $5,190,000 in
1979 dollars. For the replacement of 44 pumps, this is equivalent to an
amortized cost of $31,000 to $118,000 per pump, in 1979 dollars. Although
the lack of information on exactly what costs were included in the commenter's
5-18
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calculations admits the possibility that some legitimate costs were included
which EPA is not aware of, EPA considers these cost estimates to be excessive
when compared to the net annualized installed cost of $1,444 per pump
calculated by EPA (Table A-4, pg. A-13, Docket No. A-79-27, Item V-B-1).
5.6 DEMONSTRATION OF COMPLIANCE
Five commenters felt that compliance with an emission limit standard
would be difficult or impossible to demonstrate.
Comment; Commenter XII-D-220 expressed concern about how compliance would be
determined under an emission or risk standard, since no direct measure is
possible because background levels dwarf the regulated emission levels. The
commenter felt that it would be totally inappropriate to determine whether a
facility should shut down or not based on calculations using imprecise
emission factors.
The CMA (XII-D-59) and their supporters, and Commenters XII-D-243 and
Docket No. A-79-27, Item XI-D-13 felt that it would be difficult to
demonstrate compliance with the emission limit of standards proposed for
equipment leaks under Approaches C and D. The CMA stated that demonstration
of compliance with a plant emission limit could not be done through use of
the EPA's emission calculation procedures because these procedures over-
estimated emissions; thus, a demonstration of compliance would require
bagging to measure the actual emissions. Commenters XH-D-247 and Docket
No. A-79-27, Item XI-D-13 said that continuous bagging tests are not feasible,
but that any interruption in continuous monitoring would leave the source
owner unable to demonstrate that they were not in violation of compliance.
Commenter Docket No. A-79-27, Item IX-D-13 stated that because fugitive
equipment leaks occur randomly, any attempt to demonstrate compliance would
have to use a statistically-based emission measurement program. The
commenter stated that since the proposed emission limitation is expressed on
a daily basis, his company knows of no way to assure that the cumulative
emissions from fugitive sources would always be less than the proposed
limitations.
5-19
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Response: Since the final decision does not implement one of the proposed
emission limits, the commenters' concerns regarding demonstration of
compliance are no longer relevant. The EPA does, however, acknowledge that
existing procedures for estimating emissions from equipment leaks would make
demonstration of compliance difficult (and would be impossible at facilities
with a large number of components). For this reason, EPA is investigating a
new regulatory approach that will result in quantifiable emission levels.
Comment; Commenter XII-D-199 and XII-D-247 protested the lack of testing
methodology to prove compliance, and stated that the testing protocol which
EPA and CMA had been working on for several years had still not been
finalized.
Response; Since the final decision does not implement one of the proposed
emission limits, the presence or absence of a final test protocol is no
longer relevant. It should be noted, however, that the "Protocols" document
was finalized in October 1988. Before being finalized, this document was
reviewed by CMA panel members and a number of others. The document number of
this publication is EPA-450/3-88-010; it can be obtained from the Library
Service Office (MD-35), U. S. Environmental Protection Agency, Research
Triangle, Park, North Carolina 27711, or from National Technical Information
Services, 5285 Port Royal Road, Springfield, Virginia 22161 (NTIS
No. PB-89-138689), at $21.95 per copy.
5.7 APPLICABILITY OF STANDARDS
Comment; One commenter (Docket No. A-79-27, Item IX-D-05, Docket No. A-80-14,
Item XII-D-04) requested clarification as to whether independent "for hire"
storage vessels which do not have any processing equipment, do not process
benzene, and are not connected to or dependent on petrochemical processing
plants or refineries, would be subject to the proposed equipment leaks
regulations. The commenter read 40 CFR 61.110 (the section on applica-
bility), as applying to process plant equipment. Furthermore, according to
the commenter, the throughput and pressure assumptions found in the BID on
benzene equipment leaks showed that EPA. did not study static storage
conditions of public storage terminals, but limited the scope to process
5-20
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industries. Therefore, the commenter strongly opposed any proposal in
Subpart J which would introduce an emissions limitation on the public storage
industry.
Response: Like the existing standards in Subpart J of Part 61, Title 40, the
proposed alternative standards applied to each of the following equipment in
benzene service: pumps, compressors, pressure relief devices, sampling
connection systems, open ended lines or valves, valves, flanges and other
connectors, product accumulator vessels, and any control devices or systems
required by the standards. Facilities storing benzene, or materials
containing greater than 10 percent benzene (by weight), include equipment
such as pumps and valves that are in benzene service. Thus, any storage
terminal with a throughput of 1,000 Mg of benzene per year or greater is
subject to the requirements of the standard for equipment leaks of benzene.
The applicability of the standard to storage terminals has not changed since
the standard was promulgated (June 6, 1984, 49 FR 23948). The commenter's
association apparently was aware that the standard was applicable because
they notified association members of the standard and the 60-day period for
filing petitions for review (Docket No. A-79-27, Item IX-J-11).
The commenter's specific arguments to support his position that the
standard should not apply are also inconsistent with the intent and efforts
associated with the standard. Independent terminals were included in the
analysis of emissions and risks from facilities with equipment in benzene
service as well as in the assessment of impacts of the standard. These
analyses are presented in "Benzene Fugitive Emissions - Background Information
for Promulgated Standards." Publication No. EPA-450/3-80-032b, June 1982
(Docket No. A-79-27, Item V-B-1) as well as in various memoranda to the
docket (Docket No. A-79-27, Items IV-B-7, IV-B-11, and IV-B-15). As shown in
the BID and the memoranda, emissions from equipment leaks depend on the
number and type of equipment in benzene service and are not related to static
pressure. The throughput (or quantity of benzene handled) is only related to
emissions in the sense that fewer pieces of equipment would be used at very
small operations than at very large ones. Since the basis for estimating
emissions and risks from storage terminals (Docket No. A-79-27, Item IV-B-7)
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Is a facility with just one pump, EPA believes that the conditions at
independent storage sites have been adequately considered in the development
of the standard.
The commenter's interpretation that the standard only applies to process
plant equipment is based on a narrow interpretation of the language. The
comcnenter interpreted the term "use of benzene" in Section 61.110 of the
existing standard and Section 61.111(b)(2) of the proposed alternative
standards to mean only "to consume benzene." There are other definitions of
the word "use." In this case, the word is being used in the sense of, to
carry out a purpose or action, by means of, or utilize. In this sense, the
material being stored (i.e., benzene) is used to provide a service. Thus
equipment at storage facilities uses benzene and is subject to the standard.
Comment: Commenter XII-D-199 pointed out that EPA seemed to ignore emissions
from spills resulting from process upsets, and felt that this source would be
included in the fugitives source category.
Response: The commenter did not provide sufficient information for EPA to
determine whether the spills about which he was speaking are accidental, or
are from equipment presently subject to Subpart J or some other regulation.
If the process upsets or spills truly are the result of an accident, then
their emissions are subject to the accidental release regulations in the
SARA Title III, Section 304.
If the spills are from equipment subject to Subpart J, then these would
be regulated by the current Subpart J requirements to minimize emissions.
Without more information, EPA cannot determine the nature of the problem.
5.8 WORDING OF STANDARDS
Comment: Two commenters (XII-D-32 and XII-D-59) objected to EPA requiring
the use of a draft document ("Protocols for Generating Unit-Specific Estimates
for Equipment Leaks of VOC and VHAP - Draft") in Section 61.113(a) under
Approaches C and D. Commenter XII-D-32 recommended that EPA either finalize
the document before promulgation of the benzene equipment leaks standards, or
not refer to it in the wording of the regulations for Approach C or D.
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Response: The "Protocols" document was finalized in October 1988. Please
see the response to a similar comment under the previous "Demonstration of
Compliance" section.
Comment; Commenter XII-D-220 requested clarification on the statement in the
preamble, "This 14 kg/day limit would apply to benzene emissions from all
equipment contacting benzene at each and any plant site which contains
equipment subject to the existing NESHAP", saying that the phrase "all
equipment containing benzene" implies that equipment contacting less than
10 percent benzene (not currently covered under the existing NESHAP) would be
included in the emission limit if benzene NESHAP equipment is present at the
facility. The commenter objected to this if it was the EPA's intent. The
commenter requested clarification on the scope of the facility emission limit,
and recommended that the last sentence of Section 61.112(d) (Approach C) and
Section 61.112(a) (Approach D) should be changed for clarification to "Leaking
equipment shall include only equipment in benzene service".
Response: Since the standards proposed under Approach D are not being
established, this question concerning the applicability is no longer
relevant.
5.9 REPORTING AND RECORDKEEPING REQUIREMENTS
Comment; Commenter XII-D-59 urged EPA to make sure that if additional
equipment leak limitations are added to Subpart J (National Emission Standard
for Equipment Leaks of Benzene), that the revised Subpart J reporting and
recordkeeping requirements do not duplicate and are consistent with comparable
requirements under Subpart V (National Emission Standard for Equipment
Leaks). Commenter XII-D-32 also stated that the proposed 40 CFR 61.114 and
40 CFR 61.115 requirements for both Approaches C and D duplicate, in some
cases, the already existing corresponding requirements of 40 CFR 61.246 and
40 CFR 61.247. The commenter urged EPA to review all reporting and
recordkeeping requirements, and eliminate redundancy.
Response: Since the existing standard has not been revised, this concern is
no longer relevant.
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Comment: The commenter (XII-D-32) advocated that the required period for
reporting monitoring results in 61.115(a)(3) and (a)(2) for Approaches C and
D respectively, be extended from 30 days to 90 days, explaining that 30 days
would be too short for large plants.
Response; Since the existing standard has not been revised, the reporting
requirements have not been affected and the commenter's concerns are now
moot.
Comment: Commenter XII-D-32 suggested that wording of 40 CFR 61.114(b)(4) as
proposed under Approach C, which requires recording of "all maintenance and
repairs to each air pollutant control device in controlling benzene
emissions", be clarified to indicate that it applies only to the specific
control devices required by 40 CFR Subparts V and J.
Commenter XII-D-59 wrote that the proposed Sections 61.114(a)(3) and (4)
under Approach D is too broad, and suggested it be modified by adding the
phrase "subject to Section 61.112" at the end of paragraphs (3) and (4).
Response; Since the standard has not been revised, the commenters' concerns
are no longer relevant. The EPA would like to clarify that it was not
intended for 40 CFR 61.114(a)(3) and (4) under Approach C, and 61.114(b)(3)
and (4) under Approach D to apply to all equipment at the plant site, but
only to the equipment subject to the requirements of 40 CFR Subpart V.
Comment: Commenter XII-D-32 also suggested that existing requirements of
40 CFR 61.242-ll(e) are preferable to those of 40 CFR 61.114 under
Approaches C and D since they can be satisfied by automatic instrumentation
and alarms rather than recordkeeping.
Response; Since the existing standard has not been revised, the monitoring
requirements have not been affected and the commenter's concerns are now
moot.
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6.0 COKE BY-PRODUCT RECOVERY PLANTS
6.1 CONTROL TECHNIQUES
Comment; Commenters VI-D-1, VI-D-2, and VI-D-5 In Docket A-79-16 note
concerns regarding the safety of coke oven gas-blanketing systems like the
one EPA costed as the basis of the proposed standard for process vessels
under Approaches A, B, and C. In support, the commenters cite the report,
"Review of EPA NESHAP Methodology for Benzene Emissions and Risk Assessment
of the Manifolded Venting System on U.S. Steel's Gary, Indiana, Coking
Operations" (Docket A-79-16, Docket Item VI-E-7). In general, the report
and the commenters compare risks under current plant conditions without gas
blanketing to projected risks with installation of a gas blanketing system
designed and costed by Kaiser Engineers for the USS Gary plant. The report
and the commenters conclude that the blanketing system would increase worker
risk, the risk of overpressure or underpressure of vessels, and the severity
of potential fire or explosions. Commenter VI-D-2 also notes the potential
safety problems associated with the introduction of explosive or oxygen-
deficient gas into parts of plants where it is not currently present.
According to the report, the size and the complexity of the design also
would lead to system failures that result in higher emissions than under
existing conditions. System reliability and safety would be enhanced only
if natural gas or nitrogen were used as the purge gas and if a feed-forward
positive pressure purge system that incorporates additional safety features
were installed.
The report and Commenters VI-D-1, VI-D-2, and VI-D-5 also describe
potential operating problems with gas blanketing systems that contribute to
safety concerns. In general, the commenters do not believe that insulated,
steam-traced lines are sufficient to alleviate clogging and fouling
problems. Commenter VI-D-1 also describes fouling problems that could
affect pressure control devices and instrumentation, and how clogging in the
gas manifold could result in a tank collapse. In addition, Commenters
VI-D-2 and VI-D-5 believe the analyses overstate the extent that gas
blanketing has been demonstrated as an emission control technique.
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Response; The EPA has worked with the Industry and independent experts
over the past 10 years to understand the features of gas blanketing systems
already installed and to include features in the cost analysis for safe and
effective operation. Prior to initial proposal of the standard in 1984, EPA
thoroughly evaluated the safety aspects of gas blanketing systems. This
review included visits to each of the five plant sites with blanketing
systems to discuss safety and operating problems with plant personnel. No
safety or operation problems were reported that routine maintenance would
not resolve (Docket A-79-16, Docket Items II-B-45, II-B-46, and II-B-47).
Appropriate safety features also were evaluated by an independent consultant
(Docket A-79-16, Docket Item II-B-49). In addition, since the 1988
proposal, EPA learned that gas blanketing systems are present at three
additional plants. No comments have been received by EPA regarding safety
or operating problems with these systems.
The system costed by EPA as the basis of the proposed standards under
Approaches A, B, and C includes such features as flame arresters; an
atmospheric vent on the collecting main or gas holder to relieve excess
pressure; three-way valves to lower the possibility of operator error; and
steam-traced lines with drip points, condensate traps, and steam-out
connections (coupled with an annual maintenance check) to reduce plugging
problems. The EPA considers that the provisions included in the standards
are adequate to ensure proper operation and maintenance once a system is
installed and that adherence to these provisions will reduce or eliminate
factors that cause unsafe conditions. Although the EPA has carefully
reviewed the report submitted by the commenters in support of their
concerns, the Agency remains convinced that, with proper design, operation,
and maintenance, the system costed as the basis of the standards does not
pose the degree of safety problems alleged in the report. The points raised
by the report and the commenters are addressed below.
The report submitted by the commenters is based on an interpretation of
the gas blanketing system costed as the basis of the 1984 proposed stan-
dards. The risk estimates in the report are derived from company
confidential data for plant accidents (and near accidents) under current
conditions. These data were applied to fault tree (i.e., logic diagram)
models for each type of equipment or vessel and each of the potential
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hazards cited In the report. A composite diagram for each equipment type
and hazard combination then was generated to provide an overall Incident
frequency reflecting the actual total number of vessels in which such an
event could occur.
The report concludes that the use of a manifold system like the one
costed as the basis of the standards Increases worker risk compared to
current plant conditions. Higher worker risk 1s projected to result due to
short-term exposure to higher concentrations of benzene from excess gas
releases caused by operator error or pluggage of the system, Including
safety equipment (e.g., pressure relief devices) and Instrumentation.
The EPA notes that the report attempted to compare worker exposure
under current conditions (i.e., no gas blanketing) to hypothetical risks
with gas blanketing. However, for current conditions, the report used the
estimated concentration of benzene 300 meters downwind as the basis for
continuous worker exposure. No account was taken of the higher exposures
that occur to those operators whose normal duties require them to be near
openings on the process vessels. The comparison of worker exposure with and
without gas blanketing is not quantitatively valid for that reason. The EPA
believes that worker risk will decrease from current levels with implemen-
tation of gas blanketing system controls. Excess gas releases as described
by the commenters should occur infrequently with a system that 1s properly
designed and maintained. If an emergency pressure release does occur and
the pressure relief device remains open, the source should be Isolated from
the blanketing system until repairs are made. After the source is
isolated, the mass emission rate from the source would be no worse than when
it is uncontrolled, and furthermore, would last only until repairs are made.
Provisions also are included in the standards to reduce or eliminate the
factors that can cause excess gas releases (e.g., annual maintenance checks
and semiannual leak detection and repair requirements). In addition, high-
pressure water cleaning can be used as needed to keep lines free from
pluggages and three-way valves can be used to reduce the potential for
operator error.
The report contends that the risk of overpressure or underpressure of
vessels is increased by changing from open-vented tanks to a positive
pressure system. The EPA agrees that the probability of overpressure or
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underpressure of vessels will Increase. With open-vented tanks, emissions
are released to the atmosphere continuously rather than contained within the
system. The Installation of any emission control device or system on an
open-vented tank will increase the pressure within the tank over current
levels. The gas blanketing system design costed by EPA as the basis of the
standard would produce only slight positive pressure; tanks in good
condition (or upgraded to good condition) can accept this pressure.
Pressure/vacuum relief devices would be Installed on each vessel to prevent
catastrophic failure, and emergency vents on the collecting main or gas
holder are usual Industry practice. The EPA believes that these provisions
are sufficient safeguards to prevent serious overpressure or underpressure
of blanketed vessels. The commenters1 contention that these overpressure or
underpressure events will cause greater worker exposure has been addressed
above.
According to the report, use of a positive pressure plantwide
manifolding system violates the principles for safe design and increases the
severity of potential fires or explosions because of propagation to other
vessels connected via the blanketing system. However, the manifolding
system included in the design costed by EPA is subdivided Into small groups
of similar vessels (e.g., tar vessels, light-oil vessels, etc.). Review of
a cost report by Kaiser Engineers for the USS Gary plant submitted by the
commenters Indicates the presence of three manifolds, one of which is
connected to 20 sources. The EPA believes that subdivision of the blan-
keting system reduces the risk of propagation. The system costed by EPA
also Includes flame arresters for each vessel to reduce the potential for
propagation of fire or explosions; it 1s unclear to EPA if the design used
as the basis of the fault tree hazard analysis incorporates these safety
devices. As recommended in the principles for safe design described in the
report, provisions for efficient and safe maintenance of the system are
Included 1n the requirements of the standards.
Commenter VI-D-2 also notes concerns regarding the potential safety
problems associated with the introduction of explosive or oxygen-deficient
gas Into areas of plants where it is not currently present. It is typical
for coke oven gas to be widely distributed throughout coke and associated
steel plant installations as a fuel gas. The distribution of coke oven gas
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for gas blanketing Is no less safe than typical current practice. With
respect to the claim that coke oven gas is being introduced into places
where it is not currently present, coke oven gas is in fact present at many
of these sources. Dissolved or entrained coke oven gas is the cause of
emissions from many of these sources, such as tar decanters and tar
intercepting sumps. This may be less true for some sources such as tar
storage. However, with proper closure and sealing of such vessels,
introduction of coke oven gas to these sources is no less safe than storing
the gas in a gas holding tank.
The report also alleges that the size and complexity of the blanketing
system will lead to failures that result in higher emissions than under
existing conditions. However, industry operating experience does not
support the contention that the size and complexity of a system like EPA
costed as the basis of the standards will lead to frequent or major system
failures. As discussed further below, gas blanketing systems are currently
in use at a number of plants with no reported system failures. The EPA
believes that the potential for system failure would not be due to the size
and complexity of the system (as the report points out, the feed-forward
design suggested as being safer is even more complex), but to improper or
inadequate operation and maintenance. The EPA also doubts that incidents
leading to system failure would occur as frequently as estimated in the
report or that resulting emissions would be higher than under existing
conditions. The fault tree diagram and the specific scenario given as the
basis for the frequent overpressure and underpressure events (i.e., a system
coated with heavy organlcs) is based on an event probability not supported
in the report. The scenario itself also should not occur in a well-
maintained system.
According to the report, system safety would be enhanced only with the
use of natural gas or nitrogen as a purge gas in a feed-forward positive
pressure system. The feed-forward system recommended in the report differs
from the system costed by EPA in that the design has a purge gas supply,
adjusted with a pressure control valve, that allows makeup gas (natural gas)
to regulate the pressure whenever vessel pressure falls below a specified
limit. The natural gas flows through pressure control valves and the purge
gas flow indicator into the vessel. When vessel pressure rises, the gases
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would vent via a sealpot to a receiving coke oven gas manifold. The vent
line from the vessel to the sealpot contains a dlpleg designed to maintain a
water seal between the vent line from the vessel and the manifold system.
The water level In the sealpot Isolates the vessel vapor space from the
manifold system vapor space to prevent any fire or explosion from
propagating from the vessel to the manifold and visa versa. The vessel
pressure would be monitored by the field operator via the vessel pressure
Indicator on the vent line from the vessel to the sealpot; the control room
operator would monitor both a pressure recorder and a pressure alarm. The
water flow Indicator from the sealpot would be monitored periodically by the
field operator. According to the report, these protective systems (the
manifold vent via the sealpot, the pressure/vacuum safety valve, and the
high- and low- pressure alarm and other pressure and flow Indicators for the
purge gas) decrease the risk of overpressure or underpressure, fire or
explosion, and excess purge gas releases as compared to the positive
pressure manifold design studied in the report.
The EPA believes that the system costed as the basis of the standards
1s. safe and efficient and does not agree that the design recommended in the
report should be the basis of the nationwide cost estimates. However, the
modifications suggested in the report may include desirable (although more
costly) design features that companies may want to consider. The standards
certainly would not preclude the use of an alternative or modified design
with additional features or the use of nitrogen or natural gas as a purge
gas or as a blanketing agent, as gas blanketing designs are expected to vary
according to site-specific factors. The EPA made a preliminary cost
estimate for nitrogen blanketing and estimated the cost to be in the range
of 20 to 75 percent higher than the cost of coke oven gas-blanketing.
Commenters VI-D-1, VI-D-2, VI-D-5, and VI-E-7 contend that operating
problems such as potential plugging and fouling of lines and devices
contribute to safety concerns. Commenter VI-D-1 describes how pressure
reduction devices must be installed to reduce the normal pressure of the
plant (18-20 Inches water column) to the pressure that most vessels are
designed to handle (1-2 inches) and how fouling would affect the pressure
control mechanism and the instrumentation. The commenter also points out
that coke oven gas contains compounds that are corrosive to many types of
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metal surfaces, which could cause seals and 0-r1ngs to malfunction, further
compounding the unreliability of Instrumentation. Condensation of compounds
such as naphthalene in the gas manifold also could restrict the gas-carrying
capacity of the manifold sufficiently that pressure or vacuum might not be
relieved during liquid transfer operations. According to the commenter. one
coke plant has experienced a tank collapse as a direct result of such a
restriction. '
In response to similar comments on the 1984 proposal, EPA included in
the standards proposed under Approaches A, B, and C provisions requiring an
annual maintenance Inspection of the gas blanketing system for signs of
pluggages, sticking valves, and clogged condensate traps. Good operating
practice also would include checking sampling/gauging Instrumentation and
seals, as well as pressure control or reduction devices used in blanketing
systems no matter what the blanketing gas (e.g., clean coke oven gas, dirty
coke oven gas, nitrogen, or natural gas) during the annual maintenance
inspection. Companies should include any additional items or features 1n
the annual inspection they feel are needed for safe operation of the control
system and should make more frequent inspections 1f needed to comply with
site-specific or corporate safety policies or operating plans.
Commenters VI-D-1, VI-D-2, VI-D-5, and VI-E-7 do not agree that
Insulated, steam-traced lines are sufficient to alleviate clogging and
fouling problems. According to the commenters, some tar will deposit on
pipe walls and cannot be removed by steam cleaning even when Insulated,
steam-traced lines are used; periodic shutdowns have been recommended by
design firms in order that high-pressure water cleaning can be performed.
Commenter VI-D-1 specifically does not agree with EPA's judgment that
because most plant operations would cease until power was restored,
naphthalene clogging poses no threat in the event of a power loss.'
According to the commenter, the coking process would continue in the event
of a loss of power, thereby generating offgasses containing coal chemicals
that could clog valves and lines. This would create a risk of venting or
process upsets. Moreover, there may be a failure of the steam tracing
(e.g., a trap may freeze) that leads to naphthalene clogging even though
there has been no general power loss.
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The EPA considered requiring high-pressure water cleaning as part of
the maintenance inspection. However, site-specific factors generally
dictate if and when high-pressure water cleaning 1s needed. The use of
high-pressure water cleaning or steam cleaning 1s recommended as part of the
annual maintenance inspection, or on a more frequent basis as needed.
The EPA agrees that a failure of the steam tracing (e.g., a trap may
freeze) could lead to naphthalene clogging even if there has been no general
power loss. However, frozen traps or other equipment can occur at any
facility operating in cold climates. Although the regulation requires that
the annual maintenance inspection Include clogged condensate traps, EPA
suggests that companies consider routine inspection of traps during freezing
weather for evidence of clogging. Companies also may wish to consider the
use of a purge gas design that keeps the gas moving continuously and reduces
the probability of clogging. The feed-forward system is an example of such
a design. The EPA notes, however, that such designs are more complex and
costly due to the additional piping and purge gas consumption.
Commenters VI-D-2 and VI-D-5 contend that the analyses overstate the
extent that gas blanketing has been demonstrated as an emission control
technique. The commenters state that blanketing is not fully demonstrated
because one plant cited in the BID as using a coke oven gas-blanketing
system has since switched to nitrogen to reduce plugging problems. At this
plant, blanketing of a limited number of light-oil sources was done
originally to improve light-oil product quality, not for emissions control.
Another commenter questions the total of 24 plant years of experience cited
by EPA (Docket A-79-16, Docket Item VI-E-7). According to the commenter,
proprietary information indicates that some of the plants to which EPA
refers have had problems with the positive pressure manifold system, or have
been closed during part of the 24 year period.
The EPA disagrees that the analyses overstate the Industry's operating
experience with gas blanketing systems. Gas blanketing from the collecting
main was installed at Armco's Houston Works between 1976 and 1977 and was
operated successfully until the plant shutdown in 1981 for economic reasons
not associated with the emission control system. As of 1984, gas blanketing
of the light-oil plant had been demonstrated at Bethlehem Steel-Sparrows
Point, LTV-Cleveland, and the Armco-Houston plant. At the Sparrows Point
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plant, gas blanketing was Installed In Plant B In 1954, and a similar system
was Installed In Plant A as part of the conversion to a wash-oil final
cooler. The gas blanketing system at the LTV-C1eve!and plant was Installed
1n 1960. At this plant, the light-oil system at the No. 1 coke plant is
partially gas-blanketed.
The EPA agrees that reduced muck formation and Improved product quality
is a benefit of gas blanketing for light oil plants. However, gas
blanketing 1s also an emission control system. The fact that one of these
plants switched to nitrogen to reduce plugging problems does not detract
from their successful demonstration and operation of a blanketing system.
The proprietary information mentioned by the commenter suggesting problems
with the positive-pressure manifold system at one of these plants was not
provided to EPA for review. However, problems with the manifold system
could result if the system were not being properly operated and maintained.
Provisions are included in the standards to ensure that blanketing systems
are properly operated and maintained after installation.
Since the 1988 proposal, EPA has learned that gas blanketing is present
at three additional plants. A negative pressure system is now used at
National Steel-Granite City to control emissions from the four tar decanters
and the tar condensate sump; the negative pressure 1s provided from a tie-in
to the suction main upstream of the primary coolers. A positive pressure
system using clean coke oven gas is applied to four light-oil condensers.
At the LTV-South Chicago plant, all by-product sources are now gas-blanketed
with nitrogen and at the LTV plant in Warren, Ohio, the light-oil plant is
gas-blanketed with coke oven gas. In summary, EPA considers that gas
blanketing has been fully demonstrated within the Industry as a safe and
effective emission control technique.
Comment; Commenter VI-D-1 in Docket A-79-16 states that while
gas blanketing may be appropriate for new installations where tanks are
designed to be pressurized, tanks at existing coke plants were never
designed to be pressurized or designed to operate at negative pressure.
Also, many of the existing tanks are of a riveted design which were not
designed to be gas-tight. Commenters VI-D-2 and VI-D-5 in Docket A-79-16
note that the added stress on old welds or embrittlement of the steel if new
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welds are made while repairing and reconstructing the old tanks to handle
positive pressure could lead to failure. In support, Commenter VI-D-2 cites
an article discussing the collapse of an Ashland 011 dlesel fuel storage
tank caused by a brittle steel fracture emanating from a flaw 1n the tank's
bottom course steel plate. According to the article, brittle steel
fractures have been documented 1n older steel construction, resulting from a
combination of stress and cold temperatures.
Response; The commenters contend that retrofitting existing tanks to
accept gas blanketing poses a danger of tank failure, particularly for old
or riveted tanks. The EPA agrees that vessel upgrading, ranging from minor
repairs to total replacement, may be needed on many vessels before
Installation of blanketing systems. The EPA does not agree, however, that
necessary modifications cannot be performed on existing vessels since gas
blanketing systems were installed on existing vessels at LTV-South Chicago,
LTV-Cleveland, Bethlehem-Sparrows Point, and National Steel-Granite City.
A gas blanketing system also was successfully Installed and operated at the
Armco-Houston plant prior to its closure.
The Ashland Oil spill cited by Commenter VI-D-2 did not involve a gas-
blanketed vessel. The incident is an example of the danger posed by older
tanks in poor condition. It also is an example of the need for close
Inspection and testing of tanks being repaired and reconstructed. In fact,
the article cited by the commenter states that the company did not perform a
full hydrostatic test by American Petroleum Institute (API) Method 650, the
preferred method under API voluntary standards, prior to putting the tank in
service; that x-ray examination would have revealed the flaw; and that
"while the old steel used in the construction of the tank was in excellent
condition, it would not have been used if current API 650 standards had been
adhered to". In Congressional hearings on bills under consideration to
prevent such spills in the future (e.g., S 2020, The Above Ground Storage
Tank and Spill Prevention Act), a company spokesman acknowledged that
Ashland did not secure a written permit before constructing the tank and did
not follow adequate testing methods before filling 1t (Docket A-79-16,
Docket Item VI-J-6).
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Several of the existing coke by-product recovery plants were
constructed 1n the 1940's and have not been modernized. Many of the tanks
at these plants currently are vented to the atmosphere. Control of these
emissions by any device or system may necessitate upgrading tanks to be able
to accept a slight degree of pressure. The EPA contends that the Issue at
hand is not that older tanks at existing facilities cannot be upgraded to
modern standards, but that additional costs will be incurred for some
vessels that may require replacement or more than minor repairs. The
standards include costs for minor repairs and for sealing vessels, but do
not Include costs for substantial upgrading or replacement. The EPA does
not feel that the regulation should assume these costs because the Industry
will need to replace or substantially upgrade aged tanks 1n poor condition
that do not meet current construction standards. Modernization of existing
equipment may be needed as a routine part of plant maintenance. The
industry may consider that it is reasonable to replace these tanks now
rather than later. If replacement is done now, some additional costs over
the costs estimated for the air standards will be incurred.
Comment; Commenter VI-D-1 in Docket A-79-16 does not agree with EPA's
estimate of 98 percent control efficiency for gas blanketing systems based
on coke plant operator experience. According to the commenter, coke plant
operators state that significant downtime for the system is needed to
perform regular maintenance on both the controls and instrumentation. In
addition, operating records and design/engineering firms indicate that
complete system shutdown is needed on at least a quarterly basis to perform
high-pressure water cleaning. This cleaning necessitates that the tanks and
vessels be open to the atmosphere. According to the commenter, the downtime
for regular maintenance and for periodic line cleaning reduces the control
efficiency below 98 percent.
Response; Commenter VI-D-1 contends that downtime for regular
maintenance and for periodic (e.g., quarterly) high-pressure water cleaning
reduces the efficiency below 98 percent. Although the commenter did not
submit the operating records to which he refers that would document the
length and frequency of shutdowns for maintenance, EPA does not believe that
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emissions from quarterly shutdowns would reduce the efficiency of gas
blanketing to a large degree. For example, uncontrolled benzene emissions
from sources to be gas-blanketed at a medium-size model furnace coke plant
would total about 450 Mg/yr or 1.2 Mg/day. If the maintenance downtime were
4 days annually, emissions would be 4 times 1.2 Mg/day, or about 1 percent
of annual uncontrolled emissions.
Comment; Commenter VI-D-2 of Docket A-79-16 recommends that the final
standards allow Installation of a pressure/vacuum relief breather valve and
flame arrestor as an alternative to gas blanketing for the control of
benzene emissions from light-oil condenser vents. The commenter contends
this alternative 1s available, would be effective 1n preventing evaporative
losses during normal operations, and would avoid safety and operating
problems that can be created by gas blanketing controls on this source.
Commenters VI-D-2 and VI-D-10 In Docket A-79-16 also state that gas
blanketing should not be required for tar-intercepting sumps because of
potential safety and worker exposure problems. The commenters contend that
any leak 1n the gas blanketing system would be at a level where exposure is
likely because tar-intercepting sumps are located at, or below, ground
level. Instead of gas blanketing, the final standards should control
benzene emissions from tar-intercepting sumps in the same way as light-oil
sumps (e.g., enclose and seal the liquid surface). This control approach
would reduce benzene emissions and would avoid the risk of employee exposure
problems.
Response; Based on the information submitted by the commenters, EPA
cannot determine if the use of a pressure/vacuum relief breather valve and
flame arrestor as an alternative control system for light-oil condenser
vents would provide as much control as the gas blanketing system. The
commenters appear to be recommending that the pressure relief breather valve
serve as the emission control device. However, 1f the pressure relief
device were used in this manner, the gas flow from the condenser vent (which
1s typically released at a low, but continuous rate) would create a constant
pressure on the device. This constant pressure would force the device to
open and release the pressure on a continual basis. In contrast, pressure
6-12
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relief devices 1n the gas blanketing system are Intended to release gases
only under emergency conditions to reduce dangerous high pressures within
the process. With gas blanketing, such overpressure situations are not
expected to occur frequently because the system provides a path for the gas
to move freely to and from the vessels as pressures within the vessels
change. The descriptive information provided by the commenters did not
Indicate whether the pressure relief device would be vented to a control
device. However, if the device were vented to a control device, this
alternative system might achieve an equivalent amount of control to gas
blanketing.
Regarding the commenters1 recommended alternative for tar sumps, EPA
acknowledges that a sealed cover system like that required for the light-oil
sump could provide the 98 percent control efficiency estimated for the
light-oil sump if no emissions other than breathing losses were generated.
However, because entrained or dissolved coke oven gas from flushing liquor,
tar, or other by-product fluids at temperatures above ambient are typically
present, and steam may be vented Into the tar sump, a cover alone cannot be
expected to achieve 98-percent efficiency. Also, the gases would tend to
build up pressure under a cover and would have to be frequently released
through a pressure relief or similar vent. In comparison, light-oil sumps
typically contain wastewater that does not include entrained or dissolved
gases. A vent on the light-oil sump cover is allowed by the standards for
safety purposes to prevent the build up of pressure primarily from the
transfer of liquids. The standards also prohibit the venting of steam or
other gases from the by-product process to a light-oil sump. The EPA did
not assess a cover system for the tar Intercepting sump similar to that for
the light-oil sump for these reasons.
Provisions for use of alternative means of emission limitation for
process vessels, tar storage tanks, tar-1ntercept1ng sumps, and light-oil
sumps are Included in § 61.136 of the final standards. To apply for
permission to use an alternative emission control system, the standards
require that the owner or operator submit a design analysis with test data
showing that the alternative control system (e.g., a combined closed vent
system and control device) achieves a combined emission reduction efficiency
of 98 percent or more (except for a tar decanter, which is 95 percent).
6-13
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Comment: Commenter VI-D-1 in Docket A-79-16 believes that nitrogen
contamination would lower the heating value of the coke oven gas unless
natural gas is blended in to supplement the heating value.
Response; The EPA agrees that the use of nitrogen as a blanketing gas
would dilute the heat content of the coke oven gas. Assuming a unit heat
value of 550 British thermal units per cubic foot (Btu/ft3) of coke oven
gas, the reduction in heat value due to nitrogen addition to coke oven gas
through gas blanketing could be 7 to 8 percent for small, medium, and large
model plants. Additional information on the estimated Impact on heat values
of nitrogen combined with coke oven gas is Included 1n Table 2 of Docket
Item VI-B-6 in Docket A-79-16.
Comment; Commenter VI-D-5 in Docket A-79-16 agrees with EPA that
formcoking and direct reduced ironmaking (DRI) offer long-term prospects for
replacing conventional by-product coke making. However, these technologies
are at least one to two decades away, especially for large (2.5 to 5.0
million tons/yr) fully integrated plants which comprise the bulk of the
domestic steel industry. The commenter explains that coke provides three
needs in the blast furnace process. It provides a source of reducing gas to
reduce iron oxide, a source of heat for the process, and provides a
permeable bed to allow for upward flow of reducing gases and downward flow
and drainage of molten iron and slag. While partial replacement of coke by
injected fuels such as oil, gas, and coal, may be able to fulfill the first
two needs, the commenter states that none of the various formed coke
processes have demonstrated the ability to fulfill the third function. The
commenter also states that DRI will not be a major factor in reducing the
need for coke ovens because of the high costs, intensive energy needs, and
additional pollution problems of DRI-electric furnaces. Commenter VI-D-1 in
Docket A-79-16 agrees that formcoking and DRI are not yet commercially
available and adds that neither technology has undergone environmental
assessment. According to the commenter, it is not even known if foundry
coke can be replaced with formcoke. Commenter VI-D-5 adds that another
alternative technology beside DRI 1s smelting-reduction, but 1t is not
likely that this process will be commercially available in the next decade.
6-14
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However, if this process were successful, a typical commercial facility
would produce on such a small scale (less than 1 million tons/yr) that 1t
would not be a viable option for large, fully Integrated steel plants.
Response; The EPA thanks the commenters for sharing their expertise on
the development of these new technologies. The EPA agrees that more
research 1s needed on.the use of these new processes to replace large and
small furnace and foundry plants, as well as on the environmental Impacts.
While EPA does not disagree that new steelmaking technologies are not yet
ready for broad commercial application, we are not as certain that the new
processes are as far away from commercial viability as the commenters
suggest. Many other Industrialized countries that do not have access to
abundant supplies of low cost energy (e.g.,-natural gas, electric or
hydroelectric power) are moving ahead with new commercial processes.
Countries with pilot or commercial plants based on DRI, direct smelting, or
plasma processes Include Sweden, Japan, West Germany, Canada, Italy, New
Zealand, Mexico, Australia, Iran, Brazil, Peru, India, and South Africa, as
well as the United States. Some of these plants are producing steel 1n
quantities of about 300,000 to 500,000 tons/yr. Information on the status
of new technologies is Included in Docket A-79-16, Docket Item VI-J-4.
The by-product coking process was introduced on a large scale In the
period between 1900 and 1910 and the methods currently used by the U.S.
industry to make steel have not changed a great deal since World War'li.
New steelmaking technologies and modernized facilities may reduce or
eliminate the multi-media environmental problems now facing the industry and
many surrounding communties. The EPA believes that controls can be
engineered into these new processes and newly constructed facilities that
will decrease the environmental problems resulting from current steelmaking
operations.
6-15
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6.2 ENVIRONMENTAL IMPACTS
Comment; Commenters VI-D-1, VI-D-2, VI-D-5, and VI-D-10 1n Docket
A-79-16 believe that the nationwide emission estimates are overstated
because the 1984 data base was not adjusted before reproposal to account for
reduced plant capacities, changes in plant processes, and closures. In
support, the commenters provide updated information for use in the data base
(Docket A-79-16, Docket Item VI-E-7). Commenters VI-D-2 and VI-D-5 also
recommend that EPA not include emissions from cold-Idle plants. In support,
the commenters state that two of the seven cold-idle furnace plants have
closed and it is unreasonable to assume that the remaining cold-idle plants
will continue to operate on a continuous, full capacity basis. At minimum,
EPA should assume that no more than 50 percent of the capacity at these five
plants will be utilized in the future.
Response; The EPA agrees that the nationwide emission estimates for
the reproposed standard do not take into account the changes in capacity,
processes, and operating status that have occurred in recent years. As
stated 1n the preamble for the reproposed standard (see 53 FR 28497,
July 28, 1988), the Administrator used data and analyses that had been
revised after the June 6, 1984 proposal in his reassessment of coke by-
product recovery plants. The reanalysis, shown in the BID for the revised
proposed standard (EPA-450/3-83-016b), incorporated data available as of
November 1984.
The environmental impact estimates included emissions from cold-idle
plants because sufficient information was not available to determine if
these closures would be temporary or permanent. As discussed in the
response to comment 6.1 in the BID for the revised proposed standards
(EPA-450/3-83-016b), six furnace plants were on cold-idle (e.g., temporarily
closed but able to restart on demand). These plants included: (1) LTV
Steel-Thomas, Alabama; (2) LTV Steel-East Chicago, Indiana; (3) USX-Fairless
Hills; (4) USX-Lorain, Ohio; (5) USX- Fairfield, Alabama; and (6) Weirton
Steel-Brown's Island, West Virginia. One foundry plant, Alabama By-Products
in Keystone, Pennsylvania, also was listed as cold-idle. The BID also
6-16
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contained estimates of the capacity reductions that would result 1f these
plants were deleted from the data base.
In response to the 1988 reproposal, several commenters provided updated
Information on Industry operating status and changes 1n plant capacities and
processes. The EPA also collected additional Information from Its regional
offices (Docket A-79-16, Docket Item VI-B-5) and from responses to Section
114 Information requests from nine companies (Docket A-79-16, Docket Items
VI-D-16 through VI-D-25). This Information has been factored Into the data
base to the extent permitted by the resources available for this reanalysls.
In updating the industry operating status, EPA first had to determine
how the data base should reflect the cold-idle plants. The Agency
considered the suggestion from Commenter VI-D-2 that because of the
uncertainty in future operating plans for five cold-idle plants (USS-
Falrless Hills, Lorain, and Fairfield; LTV-East Chicago; and Inland East
Chicago plant No.3), emission estimates should be based on the assumption
that no more than 50 percent of the capacity at these plants will be
utilized. The Agency concluded, however, that the revised emission
estimates should be based on EPA's best estimate of plants currently in
operation or that may resume operation in the future. Thus, plants that
have been demolished have been removed from the data base, as well as those
plants that both EPA and the industry agree are permanently closed,
inoperable, or that would require substantial construction or a padup
rebuild before restarting (e.g., major cold-idle batteries). Plants that
are currently closed but that have batteries that could operate 1n their
current condition (e.g., hot-Idle and minor cold-idle) or that may reopen
have been retained in the data base. The EPA believes that this approach
provides the most accurate depiction of plant operating status for impact
estimates. Should any of the major cold-idle plants resume operation under
existing or new ownership, the plant must meet the requirements of the
standard upon reopening.
The EPA agrees with Commenter VI-D-2 that the LTV Steel-Thomas, Alabama
and Alabama By-Products-Keystone, Pennsylvania plants should be deleted from
the data base because they have been demolished. In addition, the LTV
Steel-East Chicago, Indiana plant was removed from the data base. Since
1984, both batteries have been permanently shutdown and will undergo
6-17
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demolition 1n the near future. All Information available to EPA Indicates
this coke plant will not ever resume operation, even under new ownership.
At the USS-Fa1rless Hills, Pennsylvania plant, the batteries have been on
cold-Idle for several years and would need rebuilding before resuming
operation. The EPA does not expect this plant to restart 1n the future.
The LTV Steel-AHqulppa plant has announced that the facility will be
permanently shutdown. The batteries have not operated since 1985 and the
company has no plans to operate the plant. Although 1t 1s possible that
this plant could be sold, major construction would be needed before the
batteries could be restarted. The Welrton Steel-Brown's Island, West
Virginia plant also 1s considered by EPA to be permanently closed and
Inoperable 1n Its current condition. Revisions also have been made 1n the
analysis to account for the permanent closure of Battery C at Inland Steel
1n East Chicago, Illinois. The other two batteries at the Inland facility
were retained 1n the data base.
The EPA also agrees with Commenter VI-D-1 that two additional foundry
plants are permanently closed. The Southern Coke plant 1n Chattanooga,
Tennessee (formerly Chattanooga Coke) had a controlled shutdown 1n 1987.
Although the batteries are not In Inoperable condition. Information from EPA
Region IV (Docket A-79-16, Docket Item VI-B-5) Indicates that the plant Is
not Hkely to restart due to economic conditions. The Carondolet plant 1n
St. Louis, Missouri closed 1n 1988. The EPA agrees that the batteries would
need a major rebuild to resume operation and the plant 1s not likely to
reopen.
The EPA does not agree there 1s clear evidence that other plants have
been permanently closed to never resume operation. For example, Commenter
VI-D-2 states that the National Steel-Detroit, Michigan plant has placed all
of Its coke oven batteries on cold-Idle and has rendered them Inoperable.
However, Information from National Steel (Docket A-79-16, Docket Item
VI-D-19) and from EPA Region V (Docket A-79-16, Docket Item VI-B-5)
Indicates that while Battery 5 1s shutdown. Battery No. 4 1s currently
operating. National Steel also stated that the company plans a rebuild of
the No. 5 battery with projected startup 1n 1992. The EPA Included Battery
5 1n the data base category "under construction", but excluded its projected
emissions from revised emission and capacity estimates primarily because the
6-18
-------
battery 1s currently shutdown. However, the 1992 startup date for operation
as a rebuilt battery also 1s too far 1n the future to know 1f or when
construction will be completed and what the Impact would be on the plant's
overall emissions. Commenter VI-D-2 also states that the USS-Lora1n Ohio
plant 1s a major cold-Idle facility (e.g., batteries would require major
construction or a padup rebuild before being restarted). However,
Information from EPA Region V Indicates that, while this 1s true for
batteries J, K, and L, batteries D, G, H, and I can potentially operate 1n
their current condition (Docket A-79-16, Docket Item VI-B-5). Commenter
VI-D-1 Indicates that Welsh Coke and Coal 1n Terre Haute, Indiana closed in
1988. While the plant Is closed at this time, Information from EPA Region V
Indicates that the batteries could potentially operate and may be restarted
(Docket A-79-16, Docket Item VI-B-5). Thus, EPA retained this foundry plant
1n the data base because It's recent closure could prove temporary. The
USX-Fa1rfield, Alabama plant was retained in the data base because more
detailed information from the Jefferson County Air Pollution Control
Department (Docket A-79-16, Docket Item VI-B-5) indicates that while
batteries Nos. 2, 5, and 6 are on major cold-idle (e.g., needing rebuild),
battery No. 9 is considered to be on minor cold-idle and may be sold. Rouge
Steel also was retained in the data base as information from EPA Region V
and the Wayne County Air Pollution Control Department indicates that three
of the batteries are on major cold-idle, but one battery (No. C) can be
•restarted and may be sold (Docket A-79-16, Docket Item VI-B-5). Because
Battery C could be restarted, EPA included it in the revised analysis as a
minor cold-idle battery.
The data base also has been adjusted to reflect changes that have
occurred in recent years regarding the operating status of Individual
batteries, plant capacities, and the processes present at each site.
Incorporated In the estimation of emissions was Information from Commenter
VI-D-2 that Inland Steel's two by-product facilities, serving different
batteries, have different sets of emission sources; additional information
was obtained from Inland's response to EPA's Section 114 information request
(Docket A-79-16, Docket Item VI-D-21). Therefore, the emissions from the
Inland Steel plant were estimated by calculating emissions from each by-
product facility separately.
6-19
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Information on revised capacities and individual battery status used in
the reanalysis is shown 1n Tables 6-1 and 6-2. Information on changes in
operating processes was provided in responses to Section 114 requests
(Docket A-79-16, Docket Items VI-D-16 through VI-D-25) and by the
commenters. This updated information is shown on Tables 6-3 and 6-4.
The responses to the Section 114 letters also included new information
regarding the baseline level of control (I.e., current control with no
NESHAP) for some plants. In particular. Docket Items VI-D-18 and VI-D-19 in
Docket A-79-16 state that gas blanketing now is used at the the LTV Steel
plants in South Chicago, Illinois and Warren, Ohio and at the National
Steel-Granite City, Illinois plant. At the LTV-South Chicago plant, all by-
product sources are gas-blanketed with nitrogen and at the LTV plant 1n
Warren, Ohio, all sources in the light-oil plant are gas-blanketed with coke
oven gas. At the Granite City plant, gas blanketing is used on the tar
decanters, the tar condensate sump, and on sources In the light-oil plant.
Emissions from the light-oil sump are controlled by use of a cover equipped
with conservation vent valves. In addition, some states (e.g., Indiana,
Illinois, Ohio, and Alabama) and counties (e.g., Jefferson County, Alabama,
Lake County/Porter County, Indiana) now require controls for some sources at
by-product plants such as naphthalene processing, sumps, and pumps and
valves. Some plants Indicated in their responses to the Section 114 request
letters that controls had been Installed on certain sources as a result of
these State or local regulations.
More detailed Information on the specific design and operation of each
control system than was contained in the Section 114 responses would be
needed to evaluate the reductions provided by these control measures. To
carry out such an evaluation and to incorporate the results Into the
calculations of baseline and regulatory options impacts would be more
resource-intensive than the other changes made to the data base.
Furthermore, and most importantly, incorporation of this information Into
the data base would not substantially change the estimated nationwide
emissions, risks, or costs, nor would it affect the maximum Individual
lifetime risk estimated for the source category. The EPA estimates that 1f
these site-specific controls were included, baseline benzene emissions would
decrease from 17,000 Mg/yr to 16,000 Mg/yr, assuming that all the
6-20
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6-32
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controls Installed by the companies achieve emission reductions equivalent
to the controls required by the standards for those sources. The purpose of
the analysis 1s to examine nationwide Impacts for NESHAP development;
therefore, whether or not these controls are Included 1n the emissions
estimates will not affect EPA's regulatory decisions. However, EPA
recognizes that the emission and risk estimates for these Individual plants
may be overstated without Including these controls In the analyses,
particularly for the National Steel and LTV plants that now have gas
blanketing systems.
The revised data base Includes a total of 25 furnace plants. Three of
the 25 plants are on minor cold-Idle; the rest are on-line although minor
cold-Idle batteries may be present. Six closed or major cold-Idle furnace
plants have been deleted. Three of the 14 foundry plants Included 1n the
1984 data base have been deleted because they are permanently closed or
demolished. Of the 11 foundry plants Included 1n the updated data base, 1
1s considered minor cold-Idle and the rest are on-line. Thus, a total of 36
plants are Included 1n the revised data base.
In the 1988 proposal, nationwide emissions of benzene and VOC from 44
plants were estimated at 26,000 Mg/yr and 171,000 Mg/yr (including benzene),
respectively. Coke production capacity for the industry was estimated at
about 50.9 million Mg/yr. In comparison, the revised data base Includes a
total of 36 plants with an estimated coke production capacity of about
35 million Mg/yr. Nationwide benzene emissions from these plants are
estimated at 17,000 Mg/yr; nationwide VOC emissions are estimated at
117,000 Mg/yr. The furnace plant industry segment accounts for about
15,500 Mg/yr of the estimated nationwide benzene emissions (or approxi-
mately 91 percent) based on a coke production capacity of about 30.8 million
Mg/yr. Foundry plants account for about 1,500 Mg/yr of nationwide benzene
emissions (or about 9 percent), based on a coke production capacity of about
4.2 million Mg/yr. Nationwide VOC emissions from furnace and foundry plants
are estimated at 106,000 Mg/yr and 11,000 Mg/yr, respectively. Tables 6-5
and 6-6 show the nationwide effects of controls on emission sources based on
the revised data base.
6-33
-------
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Comment: Commenters VI-D-2, VI-D-5, and VI-D-10 1n Docket A-79-16
believe that a different methodology should be used for estimating emissions
from vessels for which gas blanketing controls were proposed under
Approaches A, B, and C (tar decanters, tar storage tanks, flushing liquor
circulation tanks, wash-oil circulation tanks, and wash-oil decanters). The
commenters recommend that EPA use equations in the EPA document,
"Compilation for Air Pollutant Emission Factors, AP-42", for tanks storing
volatile organic liquids that consider specific vessel size and benzene
concentration of the contained liquid. The commenters contend that these
equations would result 1n better estimates than the EPA estimates, which
were based on only one to three data points with wide variability for some
sources. In support, the commenters state that the AP-42 methodology 1s
approved for use in reporting emissions under Title III of the Superfund
Amendments and Reauthorizatlon Act (SARA). The commenters also present
comparisons of Inland Steel's emission estimates for these vessels using
AP-42 submitted to the the State of Indiana for use 1n its rulemaking for
by-product plants. Sample calculations using the AP-42 equations also were
provided to EPA to show how emissions are lower based on. these methodologies
(Docket A-79-16, Docket Item VI-E-6). While the commenters believe that the
EPA emission factors for other sources are fairly representative of furnace
plants, benzene emissions from these particular vessels are lower than EPA
estimates.
Response; The purpose of the AP-42 equations 1s to estimate working
and breathing losses for fixed roof tanks storing volatile organic liquids.
Section 4.3 of AP-42 (September 1985) describes a typical fixed roof tank as
consisting of a cylindrical steel shell with a permanently affixed roof
(Docket A-79-16, Docket Item VI-J-5). According to AP-42, fixed roofs are
commonly equipped with a pressure/vacuum valve that allows them to operate
at a slight internal pressure or vacuum to prevent the release of vapors
during very small changes in temperature, pressure, or liquid level. The
introduction to the AP-42 emission equations for fixed roof tanks 1n Section
4.3.2 states that they apply only to vessels that are substantially liquid
and vapor-tight and that operate at approximately atmospheric pressure.
Openings on the vessel (e.g., from a partial or no cover, open vents with no
6-38
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pressure/vacuum valve, supplemental vents In tank sidewalls that allow wind
to pass through the vessel, warped or unsealed access hatches, etc.)
Indicate that the vessel 1s not liquid and vapor-tight. Assuming that the
vessels meet the AP-42 criteria, application of the equations may be
appropriate for some vessels at a particular coke by-product recovery plant.
However, EPA's review of Information contained In the docket Indicates that
even as of 1987, many plants have vessels (such as tar decanters and sumps)
that cannot be considered liquid and vapor-tight due to the presence of open
vents and only partial or no covers (Docket A-79-16, Docket Item VI-B-8).
Also, vessels at several of the plants would need repairs in order to be
considered liquid/vapor-tight, with warped covers on access hatches or
openings at the roof's edge. Thus, application of the AP-42 equations would
be Inappropriate for nationwide emissions estimates.
In addition, the emission mechanisms of these vessels, particularly tar
processing vessels, also are such that the equations are not appropriate for
nationwide emission estimates. For example, tar storage and tar dewaterlng
tanks are heated in many cases to remove water, which increases the flow and
concentration of emissions - a situation not accounted for by the AP-42
equations. The liquids in tar decanters and other sources also contain
dissolved gases that are released with temperature and pressure changes. In
comparison, breathing losses are caused by expansion or contraction of the
vapor volume with change in temperature or pressure. The loss of dissolved
gases Is in addition to working and breathing losses. In fact, our review
of documentation on the condition of process vessels and tanks indicates
that a high proportion of process vessels and storage tanks are heated or
hold liquids containing dissolved benzene at temperatures above ambient.
The AP-42 methodology does not estimate emissions from generation of water
vapor or dissolution of gases from these tanks. Estimates by AP-42 for
these vessels would tend to underestimate emissions.
Because the AP-42 equations are not appropriate for nationwide emission
estimates for most sources at by-product plants, direct measurements of
emissions are a preferred basis for the estimates. The field testing
performed as the basis of the EPA emission factors Included direct
measurement of vapor phase concentrations and flow rates. In comparison,
the AP-42 equations require a theoretical (and highly uncertain) estimate of
6-39
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vapor phase concentration, and the vapor flow rate 1s based only on vapor
displacement by liquid and breathing losses. As described above, the tar
decanter and flushing liquor tank, for instance, hold liquids containing
dissolved gases and thus, the AP-42 equations cannot be applied to these
sources.
Equations based on the same principles as those in AP-42 were used to
develop the emission factor for storage tanks containing light-oil, benzene-
toluene-xylene (BTX) mixtures, or benzene. These vessels tend to be covered
and sealed to prevent product loss. In addition, the liquids in these
vessels are pure, as in the case of refined benzene, or, like BTX, are
mixtures of constitutents with well-known vapor pressures. The AP-42
equations can be applied with more accurate results for these conditions
than for the nonhomogeneous mixtures contained 1n other types of vessels.
Commenter VI-D-2 also states that the AP-42 emission equations were
applied in a study of coke by-product recovery plants conducted by the
Midwest Research Institute whenever possible because of the greater
sensitivity and accuracy. However, an examination of the study (Docket
A-79-16, Docket Item VI-A-1) reveals that a different methodology was not
used and the AP-42 factors were not applied in the analysis of the Inland
plant to the extent implied by the commenter. As stated on page G-20 of the
report,
"... the use of AP-42 equations to estimate emissions from
storage tanks and process vessels may not be appropriate for
some by-product recovery streams, since these equations were
originally developed for petroleum liquids. Also, working
losses could not be accurately estimated because most process
vessels are at constant liquid level, and the capacity and
throughput do not accurately reflect changes 1n vapor space
height. As a result of the variability in emission estimating
methodologies, emissions for both the No. 2 plant and the no.
11 battery complex were estimated using both EPA's emission
factors and the stated analytical methods when possible to do
both".
Even though the report Indicates that AP-42 estimates would be
preferrable, EPA notes that the EPA factors, not the AP-42 equations, were
applied 1n most cases. This Indicates the judgement of the report authors
that AP-42 equations were not generally applicable. The emission estimates
applied for plant no. 2 and the no. 11 battery complex are included in
6-40
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Appendix G, pages G-16 and G-33, respectively. As shown on the table on
page G-16, the EPA's emission factors from the BID were applied to estimate
emissions from tar decanters and tar storage tanks. The AP-42 equations
were applied to the light-oil process vessels and storage tanks. Emissions
from trenches were estimated using mass transfer equations. The table on
page G-33 indicates that the BID emission factors were applied to all
sources except the flushing liquor collection tank and settling pits. AP-42
was used only for the flushing liquor collection tank; mass transfer
equations were used to estimate emissions from settling pits associated with
the battery 11 complex. Again, the proper application of AP-42 equations to
flushing liquor circulation tanks, light-oil process vessels, and other
vessels would depend on site-specific conditions that vary widely from plant
to plant.
The use of mass transfer equations for trenches and settling pits
deserves special comment. Although trenches are not a source for
regulation, settling pits may include tar or light-oil intercepting sumps
and these are sources for regulation. Mass transfer equations can be used
to estimate sump emissions most accurately if the liquid level is near the
top of the sump such that wind sweeps across the liquid surface of the sump.
If the liquid level is below the top of the sump, the effect of wind action
on emissions is reduced. The lower the liquid surface below the top of the
sump, i.e., the more freeboard that exists, the less applicable are mass
transfer equations. However, the liquid level of tar and light-oil sumps 1s
typically below the top of the sump. Although mass transfer equations may
be applied 1f site-specific conditions warrant, the methodology would be
inapplicable for nationwide emission estimates due to differences among the
plants.
In summary, although AP-42 equations may be appropriate for some
vessels at some plants, the equations are not appropriate for vessels at
other plants that are not liquid or vapor-tight, that are heated, or that
contain dissolved gases. Because EPA's information indicates that many of
the vessels noted by the commenters have characteristics that make the AP-42
equations inappropriate, EPA concluded that the nationwide emission
estimates for vessels for which gas blanketing controls were proposed should
not be revised using AP-42.
6-41
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Comment; Commenter VI-D-1 1n Docket A-79-16 believes that emission
estimates factors for final coolers, cooling towers, and naphthalene
processing/handling at foundry plants are too high. In support, the
commenter states test data for these sources will be provided for EPA review
(Docket A-79-16, Docket Item VI-D-14).
Response; The commenter did not provide any technical Information or
reasons to support his belief. While the commenter stated that his
organization would submit test data to be Incorporated Into the comments,
none was submitted before the court-ordered deadline of August 31, 1989 to
promulgate final rules.
6-42
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6.4 COST IMPACTS
Comment: In Docket A-79-16, Docket Items VI-E-6 and VI-E-7 contain
summaries of meetings held with representatives of the American Iron and
Steel Institute (AISI) and United States Steel (USS), a division of USX
Corporation, to discuss their comments on the revised proposed NESHAP. in
these meetings, Commenter VI-E-6 stated that the cost of gas blanketing is
higher than EPA's estimate because EPA's estimate excludes costs for tank
draining, cleaning, repairs, and other work needed to prepare vessels to
accept gas blanketing. In support, Commenter VI-E-7 refers to the 1987
report by Kaiser Engineers containing preliminary cost estimates for
installing major controls at the Gary Works (Docket A-79-16, Docket Item
IV-D-33). According to the report, the cost of repairing vessels and
installing gas blanketing controls at the Gary plant is about $8.6 million;
AISI notes in other comments that this excludes the cost of tank cleaning '
and sludge disposal (Docket A-79-16, Docket Item VI-D-2). Commenter VI-E-7
also provided a draft, order-of-magnitude engineering cost study for the
Clairton Works prepared by Kaiser Engineers. This report estimates a cost
of about $14.2 million for Clairton to perform remedial work and install
major controls. The estimate includes about $8 million for repairing,
modifying, and replacing various vessels and for adding a gas blanketing
system; an additional $5 million is estimated for vessel cleaning and sludge
removal and disposal. Commenter VI-E-6 also noted that the higher costs to
repair tanks vessels to accept gas blanketing could not be counted as part
of a vessel life-extension program. If gas blanketing were not required
the industry could operate tar tanks in their current condition because that
does not affect product quality. Thus, the industry would not need to
perform these repairs to extend the life of the vessels.
Response: The EPA estimates that the nationwide capital cost of a gas
blanketing system like the one costed as the basis of the final standards is
about $61.7 million for furnace plants and $12.7 million for foundry plants
for a nationwide total of about $74.4 million (1984 dollars). These
estimates were derived by developing control costs as a function of coke
production rate. The cost functions represent average facility costs (1 e
6-43
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the average of minimum and maximum cases). For example, the minimum case
assumes short gas-blanket piping runs and low costs to prepare vessels for
gas blanketing while the maximum case includes long piping distances and
high costs to prepare vessels for gas blanketing. Included 1n EPA's
estimates are costs for draining and cleaning vessels and for preparing them
to accept gas blanketing (e.g., replacing old covers, sealing roof openings,
patches, installing sump covers, and new roofs for some tanks). As
discussed 1n Chapter 7 of the BID for the revised proposed standard (EPA-
450/3-83-016b), these costs were prepared based on data received from
commenters following the initial 1984 proposal, in addition to cost data
developed by a third-party design and engineering firm.
The EPA agrees that higher costs may be incurred at some sites (e.g.,
Clalrton and Gary Works) to repair vessels to their original design
conditions to accept gas blanketing. However, EPA disagrees that much of
the additional costs included in Kaiser's estimates for Clairton should be
attributable to these standards. These additional costs include: (1)
replacing aged, corroded components that are due or past due for replacement
as part of periodic refurbishment, rebuilding, or good engineering practice;
(2) replacing deteriorated vessels; (3) abandoning tanks that cannot be
repaired; and (4) removing and disposing of sludge that has accumulated in
the vessels over many years. The EPA's reasons are discussed below.
The Kaiser cost estimates for the Clairton site (which is the largest
coke plant 1n the country) include approximately $4 million for vessel
repairs. According to the report, a large portion of the costs for sealing
existing vessels would be incurred due to needed repairs or replacement of
corroded equipment due to ammonium thiocyanate and chloride attack. The EPA
believes that the costs to upgrade vessels from their design condition to a
condition capable of accepting gas blanketing are fairly attributable to the
standard and are adequately represented in our estimates for typical plants.
However, much of the costs cited in the Kaiser estimates is for replacing
corroded or aged components associated with vessels that were constructed in
the 1920's and last refurbished in the 1950's according to the Inspection
records contained in the report. Based on review of the inspection records,
the Agency believes that the vessels are due for another periodic overhaul
that is part of normal plant life cycle, and good engineering practice.
6-44
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Thus, the costs for major overhaul and upgrading of the vessel components
should not be attributed to these standards.
Another cost EPA believes should not be attributable to the standards
1s for adding steam-jacketed pressure relief devices. The use of steam-
jacketed pressure relief devices rather than nonsteam-jacketed pressure
relief devices may be helpful to reduce plugging from naphthalene deposits
or freezing water. However, this is a site-specific decision and the steam-
jacketed devices are not essential, assuming the standard pressure relief
devices are properly maintained. The use of steam-jacketed pressure relief
devices on vessels amount to about $221,100 more than the standard devices
(assuming a cost of $1,300 for each standard pressure relief device compared
to $7,380 for each steam-jacketed device, a difference of over $6,000 per
device).
Of the $4 million estimated by Kaiser for remedial work at Clairton,
about $1.8 million 1s for replacing three hot drain tanks with one new
flushing-liquor collecting tank and a new spare tank, and for replacing one
light-oil recovery tank. The costs of replacing vessels in poor condition
will be incurred at some point regardless of when this rule is promulgated
because all industrial plants must eventually replace old equipment. In
fact, promulgation of this rule may accelerate the replacement of older,
deteriorated vessels, but that is an economic decision each plant must'make
(I.e., is it cheaper to upgrade existing facilities to accept controls or
replace them and put the controls on new equipment). The EPA does not agree
that the cost of replacing these vessels Is attributable to the standards.
The Kaiser estimates also include costs for cleaning and preparing 19
vessels for being abandoned in place and for dismantling 4 vessels In
preparation for replacing them as described above. The estimated cost of
preparing tanks for abandonment Is about $400,000. The cost of dismantling
four existing tanks (three hot drain tanks and one light oil recovery tank)
and preparing for replacement vessels is about $126,000. The EPA does not
consider that the costs associated with abandoning and dismantling tanks can
be reasonably attributable to the air standards.
The report also estimates a cost of almost $4 million for disposal of
tar sludge that has accumulated in the vessels over many years (excluding
costs for vessel draining, decontamination, and high-pressure water cleaning
6-45
-------
because these costs may not be Incurred at all sites). It 1s true that
sludge from the tar decanter should be removed so that vessels can be
cleaned and repairs performed prior to adding gas blanketing. Once the tar
decanter sludge 1s removed, the material (unless dellsted on a site-specific
basis) 1s a hazardous waste (K087) subject to Resource Conservation and
Recovery Act (RCRA) regulations. However, EPA notes that sludge Is
generated by the process regardless of the air controls; the Installation of
gas blanketing will not increase, decrease, or otherwise affect the volume
of sludge generated by the process. In addition, hazardous waste rules
require that this material be removed and properly disposed of whenever the
plant closes, so this cost must be Incurred for vessels holding hazardous
waste at some point in time. For these reasons, EPA considers that the
costs of sludge removal and disposal must be attributed to hazardous waste
management rather than to this NESHAP.
Commenter VI-E-6 also claimed that costs for vessel replacement and
repairs could not be considered part of a Hfe extension program because the
vessels could continue operating in their current condition without
affecting product quality. The EPA believes that product quality 1s not the
only basis for determining when life extension work is necessary. The
reported condition of some vessels at the Clairton site and the reported
date of the last major repair work suggests that life-cycle extension may be
due for many vessels. The EPA does not agree that continuing to operate
vessels in deterioriated physical condition is conducive to good safety,
operating, or engineering practice. In addition, while operating vessels 1n
poor physical condition may not affect product quality, recoverable products
or fuel are being lost to the air.
Comment; Commenter VI-D-1 in Docket A-79-16 believes the costs for gas
blanketing at foundry plants are higher than EPA estimates. According to
the commenter, the typical cost for a foundry plant to install gas
blanketing 1s at least $4 million. Gas blanketing for the merchant industry
alone would be over $40 million. The capital cost of compliance for final
cooler, cooling tower, and naphthalene processing/handling controls at a
plant is at least $2.5 million. Therefore, the anticipated cost to the
merchant industry for these controls amounts to over $25 million. The
6-46
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capital costs associated with one merchant coke plant for pressure relief
devices-Is at least $75,000 or $750,000 for foundry plants nationwide. The
costs of complying with the Inspection requirements at one merchant coke
plant Is $100,000, or $1 million for foundry plants nationwide.
Response; The commenter did not specify why (or what aspects of) EPA's
costs are too low or any breakdown or basis for the foundry plant cost
estimates. Without such Information, EPA cannot evaluate the commenter's
concerns 1n detail. However, EPA notes that for each of the costs cited by
the commenter, the commenter's estimate for the total merchant Industry cost
1s 10 times higher than the cost for a single plant. The EPA presumes that
this is because the commenter estimates there are 10 foundry plants
(according to EPA's data base there are 11) and the commenter assumed that
the same cost would apply to each plant. The Agency disagrees because not
all the controls would apply to the each plant. For example, only 6 of the
11 foundry plants included 1n the data base for the final standard have
naphthalene processing and handling. The use of rupture discs for pressure
relief devices was proposed under Approaches A and B for equipment servicing
gas or liquid containing less than 10-percent benzene. The EPA anticipates
that this equipment would most likely occur only in the light-oil recovery
portion of the plant. However, only about 6 of the 11 foundry plants
recover light-oil.
The EPA's cost estimates presented In the 1988 proposal were revised
after the 1984 proposal based on industry comments and on cost data
developed by a third-party design and engineering firm. While the costs at
a particular plant may be higher or lower than EPA's estimates due to site-
specific conditions, EPA believes the nationwide cost estimate for foundry
plants is representative for the industry as a whole.
Comment: Commenter VI-D-1 in Docket A-79-16 states that the operating
problems posed by nitrogen gas blanketing would impact both foundry and
furnace producers. However, the costs of supplementing with natural gas to
supplement the heating value of coke oven gas contaminated due to nitrogen
blanketing would be prohibitive to many foundry coke plants.
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Response; In response to the commenter's concern, EPA examined the
impact of nitrogen gas blanketing on the heat value of coke oven gas. The
results of this analysis are Included in Docket Item VI-B-6. The analysis
indicates that the addition of nitrogen from a blanketing system to coke
oven gas may decrease the heating value of the coke oven gas by 7 to 8
percent for small, medium, and large model plants, depending on the number
of sources to be blanketed. This decrease would be expected to occur
regardless of the Initial heat content of the coke oven gas. Plants with
coke oven gas having a heating value in the range of 500 to 550 Btu/ft3 coke
oven gas prior to nitrogen dilution may be able to make adjustments to their
combustion equipment (e.g., burner operating characteristics) to accomodate
the reduction in heating value without a natural gas supplement. In
comparison, plants with coke oven gas having a lower heating value prior to
nitrogen dilution (e.g., 500 Btu or less) may need to supplement with
natural gas for proper burner operation. The EPA could not estimate the
additional nationwide costs or economic impacts that might be incurred at
foundry plants for supplementary natural gas because the costs would be
highly dependent on site-specific factors such as the current heat value of
the coke oven gas (dependent on stage charging practices), the burner
designs, and the burner tolerances for fuel gas changes. However, EPA views
the decision to use nitrogen for gas blanketing rather than coke oven gas as
a site-specific decision and the standards neither require nor preclude the
use of nitrogen as the blanketing agent for any source.
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6.5 ECONOMIC IMPACTS
Comment; Commenter VI-D-1 in Docket A-79-16 submitted information
showing that currently, there is insufficient coke capacity to support
existing iron and steel casting capacity. Coke inventory levels are the
lowest since pre!980 levels and imports have increased to fulfill domestic
demand. The commenter predicts the capacity reduction will have at least
two adverse effects on the economy: (1) the impact of increasing reliance on
imported coke, and (2) the increased prices in end-use products ranging from
steel and iron castings to household products manufactured from by-products
generated from the coking process. In addition, while steel production has
recently increased, domestic coke production is expected to decline further
as the number of active plants and coking capacity diminishes.
Response; The commenter did not specifically relate the submitted
information to the proposed rulemaking. The EPA interprets the comment as a
prediction of the potential economic impacts of a regulation that would
require substantial cutbacks in production capacity, such as were estimated
for the proposed emission limits under Approaches C and D because it was not
technologically feasible for all plants to achieve the limits without
production cutbacks. The final rules are a combination of equipment and
work practice standards that are technologically feasible. Therefore, no
cutbacks in production capacity are necessary in order for plants to comply.
However, as EPA acknowledges in the summary of the impacts of the final
standards, implementation of the standards could be a factor in triggering
closure decisions at plants that are presently marginal or operating at a
loss.
Comment: Commenter VI-D-10 in Docket A-79-16 believes that the impacts
of closures are underestimated under proposed Approach D. Shutdown of the
domestic coking industry would result in the loss of 7,000 jobs at coke
plants, 100,000 jobs in iron and steel making, and 250,000 jobs in secondary
fields. If the EPA proposal is enacted, only finishing mills, employing
about 50,000 people, would be able to continue operations, assuming
semifinished slabs could be purchased on the world market. The Gary plant,
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which employs about 600 persons directly would not be able to compete 1n
these circumstances and may not be able to operate 1n the future.
Response; The EPA appreciates the commenter's perspective on the
potential Impacts of proposed Approach D. However, because Approach D was
not chosen as the basis for the final standards, the commenter's concerns
are no longer relevant.
Comment; Commenter VI-E-6 1n Docket A-79-16 believes that the actual
nationwide cost of the standards proposed under Approachs A and B
(considering additional costs for tank cleaning and other work needed to
prepare vessels for gas blanketing) exceeds $100 million and requires a more
detailed economic analysis. Commenter VI-D-10 agrees, adding that over
$25 million would be required for the Clalrton and Gary Works. This
projects to over $100 million for all domestic coke producers, classifying
the proposal as a major rule, subject to OMB review.
Response; A large part of the above cost estimates for the Clalrton
and Gary Works are for costs that are not attributable to these standards,
such as tank maintenance and the disposal of sludge accumulated from the tar
storage operation. These are discussed more fully 1n Section 6.4 of this
chapter. In addition, the types of costs cited by the commenters are
capital costs. A major rule, which requires a regulatory Impact analysis
for OMB review, is defined by Executive Order 12291 as a rule that 1s likely
to result in an annual cost of $100 million or more. The annual cost of the
final standards is estimated to be $16 million (1984 dollars), and is not a
major rule.
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6.6 MISCELLANEOUS
Comment: Commenter VI-D-1 In Docket A-79-16 recommends that the
computation of the ratio of foundry/furnace coke production used 1n the
definitions distinguishing furnace from foundry coke by-product recovery
plants be made on an annual basis. While the commenter accepts the EPA
definitions, he notes that in the discussion of the definition on page 4-2
of the BID for the revised proposed standards, EPA mistakenly identified a
corresponding increase in benzene emissions with an increase 1n the the
production of foundry rather than furnace coke.
Response; The EPA agrees with the commenter. The proposed standard
under Approaches A, B, and C included the computation of foundry/furnace
coke production on an annual basis (53 FR 28575). Also, EPA agrees that on
page 4-2 of the BID for the revised proposed standard (EPA-450/3-83-016b),
the third to the last sentence should have stated that as the percentage of
furnace coke increases, there is a corresponding increase in benzene
emissions.
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7.0 RISK ASSESSMENT
7.1 INTRODUCTION
Many commenters expressed views on various aspects or analyses in the
risk assessment. The comments ranged from the general to the specific, from
criticisms to suggestions for improvement, and from the opinion that the
EPA's analysis was too conservative because of underlying unrealistic
assumptions or methodologies to the opinion that the analysis was not
conservative enough because many factors had not been considered.
This chapter is divided into four sections; comments that deal with the
development of the unit risk estimate and health effects, with the exposure
analysis, with the uncertainty of the risk estimates, and with a mix of
policy and science issues.
7.2 UNIT RISK ESTIMATE
Many commenters discussed the EPA's unit risk estimate (URE) and the
various steps in the procedure used to develop the URE. In specific, the
commenters addressed the health effects stemming from benzene exposure that
should be considered, the data that were used, and the dose/response assess-
ment, particularly the dose/response model. These topics are presented in
the following sections. In late July, API submitted additional comments
regarding the dose/response analysis for benzene (XII-D-264). The comments
included three detailed reports. These reports were not received in time for
EPA to evaluate them before the August 31, 1989, court-ordered deadline for
promulgating final rules.
Specific Criticisms of the EPA's Unit Risk Estimate for Benzene
Dose/Response Model and Data Used
Comment: °ne commenter (XII-D-60, see also .XII-J-2) (API) submitted a new
quantitative risk assessment on the benzene-induced risk of leukemia, based
solely on the cohort studied by Rinsky (1987). An important theme presented
in the document is that the model used is an improvement over the model used
in the 1985 EPA assessment (Docket No. OAQPS 79-3, Part I, Item VIII-A-4).
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The major points raised in the commenter's risk assessment are as
follows:
a. The Rinsky study is the best of all studies and thus should be the
sole data base for risk calculations.
b. The EPA's low-dose extrapolation model for risk calculation is
inferior to the new model for several reasons. The best
epidemiological and biological data available today are
inconsistent with the linear one-hit hypothesis and support a
quadratic model as a more plausible, but still conservative,
measure of potency. The commenter stated that there is now
significant biological support for the conclusion that benzene-
induced leukemia requires at least two distinct steps, with the
best epidemiologic data indicating that perhaps more than two are
needed. The quadratic dose/response relationship yields risk
estimates about three orders of magnitude below those predicted by
the updated linear one-hit model.
c. The relative risk model should not be used because the benzene-
induced leukemia death rate is not proportional to the background
leukemia death rate at all ages.
Comment: Commenter XII-D-38 presented a mainly qualitative evaluation of
available epidemiologic studies. Three major arguments were made in this
submission:
a. Acute myeloid leukemia (AMI) is the only leukemia cell type that
can be considered, on the basis of epidemiological studies, for
quantitative risk estimation. This commenter based his recommenda-
tion on an evaluation of the six epidemiological studies for
benzene-exposed workers that EPA considered in developing the LIRE.
The commenter felt that it is inappropriate to extrapolate the risk
associated with acute myeloid leukemias to all leukemias when the
risk appears to be biologically specific to acute myeloid leukemias.
b. The existing data suggest a nonlinear and threshold dose/response
relationship.
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c. Blood count data do not correlate well with the Rinsky exposure
estimate but correlate well with the estimate by Crump and Allen
(1984), suggesting that the exposure estimate by Crump and Allen is
more reasonable and should be used for quantitative risk
calculation. The commenter compared the Crump and Allen and NIOSH
exposure estimates, and recommended that the Crump and Allen
estimates be used because they: (1) are related to the benzene
exposure standards of the time and (2) include exposure
calculations for all Pliofilm workers, not just those assigned to
the "wet side". The commenter also observed that data for the
three plant locations in the Ohio Pliofilm study conducted by NIOSH
showed that all cases of AMI occurred at one location and only
among workers in the plant prior to 1945. The commenter
recommended that the risk analysis treat each location separately,
given the possible explanation that workers in that location prior
to 1945 had a much higher lifetime benzene exposure than assumed in
the NIOSH study, and higher than those men working at the other two
locations.
Health Effects Endpoint.s
Comment: Six commenters (XII-F-14, XII-D-04, XII-D-35, XII-D-203, XII-D-216,
XII-D-254) felt that health risks were understated because other health
effects of benzene, such as cancer-causing but nonleukemogenic health effects,
noncarcinogenic health effects, interactive effects, birth defects, and
reduction of the immune system, had not been taken into account in the EPA
analysis. Commenters XII-F-12, XII-D-26, XII-D-35, XII-D-102, XII-D-130,
XII-D-158, XII-D-185, and XII-D-217 stated that all health impacts of benzene
should be considered, and implied .that risks would be understated if such
effects were not accounted for. Commenter XII-D-218 said the risk assessment
methodology should include determination of risks for noncancer effects of
benzene.
One commenter (XII-D-254) also noted that the Clement Associates report
submitted by API examined only leukemia while there are studies that indicate
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that multiple myeloma is also associated with benzene, and that there may be
other forms, or higher rates of cancer as well.
Response to Comments on Benzene Unit Risk Estimate
The comments on the risk assessment for benzene focus on the following
groups of issues:
1. The appropriateness of using Rinsky's cohort as the sole data base
for risk calculation;
2. The differences between the Rinsky data tapes used by API and the
Rinsky data tapes used by Rinsky in his 1987 published paper;
3. Indication by data from epidemiologic studies that only certain
types of leukemia .are induced by benzene;
4. Support from the Kipen et al. (1987) study on blood counts for the
assumption that the Crump and Allen exposure estimate is better
than the Rinsky estimate;
5. The sufficiency of evidence to indicate that benzene has a
nonlinear and threshold dose effect;
6. The implications by API that the EPA's procedures in the 1985 risk
assessment are inadequate with respect to API's interpretation of
the EPA's model;
7. Problems with the API procedures for risk calculation; and
8. Exclusion of other cancers and noncancer health effects, resulting
in understatement of the risk.
Outlined below is a discussion of the EPA's position on these issues,
including a review of the relevant epidemiological studies and assumptions
used by EPA in the carcinogen risk assessment.
Issue 1. Rinsky's Cohort as the Sole Data Base
The API argued that only the Rinsky study should be used for
quantitative risk assessment because it is the best among all available
epidemiologic studies. The EPA disagrees. As discussed below, there is no
reason to choose among several epidemiologic studies of varying quality, none
of which can be considered necessarily better than any other. Data from
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studies other than the Rinsky study should also be used for the purpose of
risk calculation. Although the Rinsky study possesses many of the attributes
of a good epidemiologic study, it still suffers from a lack of definitive
information concerning the levels of benzene exposure to which the Pliofilm
workers were subjected in the 1940's. As Rinsky has pointed out there are no
exposure data at Location 1 during the period 1940 through 1945 and also 1951
through 1963. During the period 1946 through 1950 there were 15 measurements
performed on four different days. At Plant 1 of Location 2, only 3 measure-
ments were taken in 1948. No exposure measurements were taken at Plant 2 of
Location 2 until 1957. Six of the 9 leukemia cases in the Rinsky cohort were
employed at Location 2. Rinsky has argued that although additional environ-
mental measurements were available during this period, those measurements
were taken in areas where no employees were ever assigned, hence those
measurements were not used. Rinsky believes that these measurements were
used in the Crump and Allen assessment and subsequently in the API-assessment.
The assumption was made by Rinsky that the levels of exposure at
Location 2 were similar to those of Location 1. Nothing has changed in any
of the updates of this study to improve upon that assumption. Rinsky has
pointed out that there has been little change in work practices, industrial
processes or engineering controls during the early years of operation, and as
a result, there would be little expectation that the levels of exposure would
have fallen during the early years. Furthermore, rising white blood counts
that were described by Kipen, et al. (1987) as providing corroborating
evidence that exposures were declining during this early period are described
by Rinsky (1989) as "artifactual" since averaged blood count levels were
observed to rise in both exposed and unexposed employees during the same
period (see Issue 4). Assumptions made by Kipen, et al. cannot overcome this
basic drawback of the Rinsky study; i.e., lack of adequate exposure informa-
tion during the early but critical years of employment of the cases. This
exposure situation argues for the use of all good data bases in the attempt
to reduce uncertainties in any one estimate of risk. None of the three
epidemiological studies used by EPA is considered to be superior to any
other.
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The EPA believes that the authors of the API document gave an incomplete
picture of other studies and therefore reduced their usefulness by leaving
out important details about those studies that argued against the use of the
Rinsky study as the sole data source. For example, a dose/response
relationship of cumulative exposure to benzene and cancer of the "lymphatic
and hematopoietic system" was noted by Wong, et al. as well as generalized
leukemia and aleukemia. The cancer types identified included 4 lymphatic,
2 myeloid and 1 acute unspecified leukemia. This is contrary to the
commenter's assumption that AML is the only type of leukemia associated with
benzene exposure. The reason the observed dose/response relationship with
respect to the lymphatic and hematopoietic system is ignored is not clear
from reading the API document. The EPA does agree with API that this study
suffers from several other deficiencies that were adequately discussed by the
authors.
A major argument by API against using the Ott, et al. study was that the
investigators did not observe a dose/response relationship between benzene
and "leukemia. The EPA believes this study demonstrated ah association
between exposure to benzene and leukemia. However, the small size of the
cohort limited the ability of the study to demonstrate a dose/response
effect.
A discussion of the EPA's assessment of benzene carcinogenicity is
presented in the July 28, 1988, Federal Register (53 FR 28496) announcing the
EPA's proposed response to the remand for the benzene source categories.
Issue 2. Differences between API and Rinsky in the utilization of Rinsky
data tapes
The API used data from the same population studied by Rinsky (1987) but
employed different cohort selection criteria. There appear to be some
differences between the Rinsky data tapes utilized by API and the Rinsky data
tapes utilized by Rinsky in his 1987 published paper. Rinsky has maintained
that a subset of the 575 "dryside" workers who had some documented exposure
to benzene were included in his data tapes. If the remaining "dryside"
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workers in this group that were added to API's cohort indeed were not exposed
to benzene, as maintained by Rinsky, the inclusion of them will serve only to
dilute risk estimates based on latency and add nothing to elucidating a
dose/response relationship.
Issue 3. Only Certain Types of Leukemia Are Induced by Benzene
The EPA disagrees with Commenter XII-D-38's inference that AML is the
only type of leukemia caused by benzene simply because it is more frequently
seen in epidemiologic studies. In addition to leukemia, several studies
(described in 53 FR 28496) have noted increases in other cancers, most
notably lymphosarcoma and multiple myeloma. There is substantial evidence
from case reports and epidemiologic studies that benzene causes all major
cell types of leukemia as well as lymphomas and other diseases (Docket
No. OAQPS 79-3, Part I, Item XII-B-1). This is consistent with the
observation that other leukemogens (e.g. radiation, oncogenic viruses,
alkylating agents and anti-neoplastic drugs) cause cancers in different cell
types. There is insufficient evidence to discount the association of benzene
with leukemia types other than AML.
The API uses only AML and aplastic anemia as disease end points for
calculating risk due to exposure to benzene. It is well established that
acute nonlymphatic leukemia is causally related to benzene exposure as well.
However, there is also evidence linking acute and chronic forms of lymphatic
leukemia to benzene exposure. There are several epidemiologic studies and
case reports associating lymphatic leukemia with benzene exposure, although
the API concludes from their literature review that "chronic leukemias were
not associated with exposure to benzene". It is imprudent to assume at this
time that these types of leukemia are not related to benzene exposure.
Rinsky found a significantly high risk of multiple myeloma in his cohort as
did several other researchers. This type of leukemia, arising out of
lymphoid tissue, also appears related to benzene exposure. The added
contribution of this particular type of cancer should be assessed.
While EPA does not disagree with API in considering aplastic anemia as a
benzene-induced disease, EPA is concerned that API's recorded mortality rates
underestimate the disease incidence because not all aplastic anemia is fatal.
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Issue 4. Blood Counts and the Crump-Allen Exposure Estimate
The evidence provided by API to justify the use of the Crump and Allen
exposure estimate is disputed by Rinsky (Docket No. OAQPS 79-3, Part I,
Item XII-B-1). Given the uncertainty associated with the Crump and Allen
exposure estimate, EPA feels that both the Rinsky and Crump and Allen
exposure estimates should be considered in risk assessment.
There are two exposure estimates for the Rinsky cohort; Rinsky's, and
Crump and Allen's. Since there are no industrial hygiene data taken prior to
1946, benzene exposure for a given job prior to 1946 must be assumed. Rinsky
assumed that for a given job the exposure levels were the same before 1946 as
they were in 1946 when some exposure data existed, since there were no major
technological changes or improvements in production or control of benzene
emissions within the plants. Crump and Allen adjusted the exposure level
before 1946 upward from the existing exposure data by multiplying the ratio
of prevailing occupational standards at the two different time periods. The
argument that the Crump and Allen exposure estimate is superior to the Rinsky
exposure estimate is based on an observation that the Crump and Allen
estimates have a high correlation with rising peripheral blood counts (higher
blood counts are associated with lower exposure estimates), while no
correlation is found for the Rinsky estimate. The EPA believes that this
finding of a high correlation is "artifactual". Blood counts rose in both
exposed and unexposed employees over time, which may have been due to changes
in diagnostic methods, techniques or interpretations. Furthermore, low white
blood cell counts would tend to bias estimates upward with time because of a
company policy that leads to the removal of such employees from exposure. It
is difficult to make a judgment about whose exposure estimate is more
appropriate based on those blood count data because of poor statistical
representation of the population that was monitored for blood evaluation.
Issue 5. Benzene Has a Non-Linear and Threshold Dose Effect
Both Commenter XII-D-38 and API claim that Rinsky's study showed a
strong nonlinearity of leukemia mortality rate with dose using either the
Rinsky or the Crump and Allen exposure estimates. Commenter XII-D-38 further
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argues that the observation of pancytopenia prior to leukemia, the short post
exposure latent period (i.e., the time interval from last exposure to death
from leukemia), and the nonlinearity of risk with exposure dose, are all
consistent with leukemia as an indirect effect of benzene.
The observed "pancytopenia" effect, which is a cytotoxic effect, of
benzene in some but not all cases preceding leukemia indeed should not be
construed as causal evidence for an indirect leukemogenic action. Such a
conclusion is only speculative given the lack of consensus about benzene
mechanism(s).
Commenter XII-D-38 has implied that a threshold dose effect exists for
benzene because of suggestions that leukemia is induced by benzene via
indirect mechanisms which are not really well established. The EPA believes
that, at this time, it is premature to assume a threshold effect due to the
lack of understanding about the mechanisms of carcinogenic action of benzene.
Commenter XII-D-38 argues that benzene acts at a later stage in the
carcinogenic process (perhaps, through action of promotion or disease
progression) because 80 percent of benzene-associated leukemia deaths
occurred no more than two years after their last benzene exposure. This
argument is at best speculative. Given that the average latent period in
Rinsky's study from first exposure is about 16-20 years, the observation that
several cases showing a short post exposure latent period does not imply that
benzene acts at a later stage of a carcinogenic process. Under the multi-
stage model for carcinogenesis, a logical way to show that an agent may act
at a later stage of a carcinogenic process is to demonstrate that the cancer
risk is much greater for older persons than young adults when they were
subjected to the same intensity of exposure for a similar duration and have a
similar period of follow up.
The EPA does not agree with the comment that the demonstration of a
nonlinear dose/response relationship in the observed data is a sufficient
basis to argue that the shape of the dose/response curve is nonlinear at
untested low dose levels. The EPA's view is that linear low-dose
extrapolation is preferred, unless low-dose data and/or mechanism of action
or metabolism data show otherwise.
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While not unique to benzene per se, there is a general argument for
linearity at low doses, which is referred to as "additivity to background".
In the additive background model proposed by Crump et al. (1976), spontaneous
tumors are associated with an effective background dose, with exposure to
carcinogens present in the environment adding to this background dose. In
this regard, Crump et al. (1976) stated that "If carcinogenesis by an
external agent acts additively with an already ongoing process, then under
almost any model the response will be linear at low doses." Hoel (1980)
subsequently demonstrated that this result also holds even in the case of
partial additivity.
Issue 6. API's Model is Superior to EPA's 1985 Model
The API considers its new risk extrapolation model to be an offshoot of
the one used by EPA (1985). The new risk extrapolation, the authors of the
API report argue, represents a significant improvement over the existing EPA
risk assessment (1985) because more biological information ( e.g., the use of
latency period actually estimated from data) is incorporated and a better
estimation procedure (i.e., the use of individual exposure information rather
than categorical data) is used. However, the assertion that their new
assessment procedure is an improvement over the EPA procedure is not accurate
in EPA's view and the way that latency is incorporated in the model is not
appropriate.
The authors of the API document claim that the following mathematic
expression, hl(t), can be used to represent the benzene-induced age-specific
cancer rate that was used in the 1985 EPA risk assessment.
hl(t) - INT{bx(v)a(v)rw(t-v)dv) (1)
where INT is used to represent the mathematical integration from 0 to t; a(v)
is the background rate at age v; r = 1 for the relative risk model and r = 0
for the absolute risk model; x(v) is the exposure at age v and w(t-v) is the
effect (weight) of the exposure incurred at age v to the cancer response at
age t; b is a parameter representing carcinogenic potency of benzene.
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The EPA does not agree that this new assessment procedure is, a priori.
an improvement over the EPA procedure because EPA believes the way that
cellular dynamics and latency are incorporated in the new model is both
mathematically and biologically inappropriate. While EPA believes that the
EPA's linear nonthreshold dose/response assessment for benzene is the most
appropriate approach at this time, EPA encourages the development of new
approaches that involve the incorporation of biological information, as
appropriate, into the risk assessment procedure.
It should be noted that Eq. 1 is only one of many possible ways to
interpret risk models used by EPA. The EPA model is a simple standard
procedure for calculating dose/response which is not intended to be a
characterization of any specific, yet, hypothetical carcinogenic process.
This procedure is considered appropriate in the absence of specific
mechanistic information. Evidence to indicate why Eq. 1 cannot be used to
interpret the EPA model is noted below. The API has used Eq. 1 to show the
implication in the EPA model that the background leukemia rate is given by
a(t) = c[l - (1 + kt)exp(-kt)]
where k =0.399 and c is a constant representing the background rate of
inducing a single malignant cell. They argue that the EPA model is not
appropriate because a(t) becomes constant, c, when age t is greater than 20;
this is contrary to the fact that background rate is highly age-dependent.
The fact is that the EPA model does not make any assumption about the
background rate: it used background rates that are reported in the U.S. vital
statistics, be they exponentially or linearly related to age. The fallacy is
that, in the API model, the background rate is now represented by a
mathematical function which includes the probability distribution of latency
period which is defined as the time interval from the beginning of the first
malignant cell to the death of a person from leukemia. As discussed in the
next section, the latency as defined and used in the model is not
appropriate.
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In its 1985 risk assessment, EPA used two models (relative and absolute
risk) and two exposure estimates (cumulative and weighted cumulative) to
calculate leukemia risk due to benzene exposure, using data from three
different epidemiological studies. This diversity of the use of data and
models reflects uncertainties perceived by EPA at the time the document was
prepared. These uncertainties remain today.
Issue 7. Problems in the API Procedures for Risk Calculation
A simplified version of the Moolgavkar (MVK) model (1979) is used by API
as the backbone to calculate benzene-induced leukemia risk. If this
simplified MVK model were used to fit the leukemia mortality data, it would
imply that a person dies immediately with a probability of one at the
occurrence of the first malignant cell. The API has made an attempt to
account for the fact that a person will not die immediately at the occurrence
of the first cancer cell by introducing the concept of latency in the model.
The latency is defined as time interval from the occurrence of the first
malignant cell to death from leukemia. The distribution of the latency
period is assumed to have the mathematic form,
w(L) = ICLexpt-KL],
(2)
where L is the latency period as defined above and k is a parameter; the
reciprocal of k is the mode of the distribution; k= 0.399 was estimated on
the basis of mortality data on leukemia induced by therapeutic radiation for
ankylosing spondylitis.
The way that the latency is incorporated by API into the MVK model is
both mathematically and biologically inappropriate because it assumes that
one and only one single tumor cell will eventually lead to leukemia death.
The API cites the paper by Wittemore and Keller (1978) in which the
probability density function (p.d.f) of the time to tumor for a normal cell
is expressed as the convolution of p.d.fs' of both time to malignant trans-
formation and the time to tumor (or death) after it becomes malignant.
Wittemore and Keller's approach is appropriate because they consider only a
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single cell which is not subject to cell proliferation before it becomes
malignant while the MVK model allows for such a cell growth; thus, a normal
cell which is initiated has a potential to produce many initiated and/or
malignant cells.
Despite the inadequacy of the methodology employed in the API risk
calculations, EPA offers the following comments about the API risk
assessment.
1. The mathematical form of the distribution function of the latency
has an effect on the final risk estimation. The reason Eq. 2 was selected is
not known except that it is mathematically easier to handle. The API
demonstration that the risk estimate is not sensitive to the selection of the
value of the parameter k is interesting but not the main issue.. The question
here is why this particular form of a distribution function was selected. In
his letter to the EPA Administrator, Dr. Hattis (XII-D-251) has also
expressed the same concern.
2. The parameter k in the latency distribution is superimposed upon
epidemiological data for which the only information known about the
epidemiologic latency period is the period of time from the first exposure to
death of a person. These data should only be used to estimate a range of
latency as defined in the API model. For instance, if a person died from
leukemia after 30 years of exposure to benzene, the only information one
could get from this case is that the first malignant cell may have occurred
when he was first employed 30 years earlier, or near the end of his employ-
ment. In this case, the latency could range from one month to 30 years.
This example suggests the inadequacy of estimating the latent period from
midpoint of employment until death and then using it to estimate parameter k,
as did the authors of the API document. This inadequacy is compounded by the
likelihood that there are some fundamental differences between benzene-
induced leukemia and radiation-induced leukemia. The API used radiation-
induced leukemia to estimate latency. According to the literature both acute
lymphatic as well as acute myelocytic leukemia appeared excessive within 2 to
5 years after the Hiroshima bomb blast, followed some 20 years later by an
increase in multiple myeloma and carcinoma. In Rinsky's cohort, however,
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nearly all of his cases of acute nonlymphatic leukemia appeared well after
the estimated median latency among those exposed to the atomic bomb radiation.
Indeed, even if one considers the midpoint of their exposure as a reasonable
estimate of the time of the first "transformation event" as did the authors
of the API document, a considerable lapse of time occurred before
manifestation of leukemia. I
',
In the Bond/Ott study, although all 5 cases were acute myelogenous
leukemia, the period of time between last exposure to benzene and death
ranged from 8 years to 18 years in 4 of the 5 cases thus indicating that the
time from transition into malignancy probably exceeded 8 years by a
considerable time period. Furthermore, 2 of these cases died from their
disease at age 80, which was outside the age range used to justify the use of
the absolute risk model. These observations highlight the problem of using a
small cohort of workers to estimate the so-called biological latency of rare
cancer. This wide range of latency for leukemia demonstrated in the
epidemic!ogical studies of benzene points out the difficulty of estimating
the biological latency period and thus casts doubt on the reliability of the
resultant risk estimate.
3. The use of individual exposure data in the parameter estimation in
general is better than grouping into categories. However, the procedure
suffers from the deficiency that the background leukemia rate must be
estimated and expressed in a mathematical function, which is very much model
dependent. This procedure, which forces the background rate to have a
certain mathematic form, unnecessarily introduces uncertainties into the risk
estimate.
4. An argument is offered to support the use of an absolute risk model
over a relative risk model. The main argument against the use of a relative
risk model is that the benzene exposure does not change the background
mortality rate by a constant fraction at all ages. This argument is not
convincing. It is not necessary to assume that benzene exposure will change
background by a constant fraction at all ages in order for the relative risk
model to be valid. The EPA does not have a preference with regard to which
model to use: either the absolute or the relative risk model. In their
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report to OSHA from which the EPA risk estimate was derived, Crump and Allen
(1984) indicate that each of the models (relative risk and absolute risk),
combined with each of the exposure measures (cumulative and weighted
cumulative), fit each of the data sets adequately, as well as combined data
from different studies. An extensive discussion and justification about the
use of absolute and relative risk models for benzene risk calculations are
also provided by both Infante and Rinsky. In summary, EPA believes that use
of both relative and absolute risk models to calculate benzene risk is
appropriate.
Issue 8. Risk is Understated by Omission of Other Cancers and Noncancer
Health Effects
Although human exposure to benzene in the workplace has been associated
with leukemia, aplastic anemia, multiple myeloma, lymphomas, pancytopenia,
chromosomal breakages and depression of bone marrow, EPA believes that the
leukemia incidence in epidemiology studies provides the most comprehensive
and up-to-date basis for dose/response estimation purposes. In benzene-
exposed animals, toxic effects such as histopathological changes in the
testes and bone marrow have been observed. Toxicity of the hematopoietic
system as well as cytogenetic effects in humans have been causally related to
benzene exposure; however, the magnitude and duration of exposure required to
elicit these effects are not developed at this time.
The estimated ambient levels of benzene associated with emissions from
stationary industrial sources after controls are applied (in the low ppb
range) are generally at least three orders of magnitude lower than the
lowest-observed-effect levels in animals (in the ppm range). However, the
carcinogenic effect, unlike noncancer health endpoints, is presumed to be
nonthreshold in nature. Consequently, in the interest of protecting public
health, EPA has identified carcinogenicity, specifically leukemia, as the
health endpoint of greatest concern in this risk assessment.
In addition to the issues discussed above, other comments received by
EPA are summarized in the following section.
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General Comments on Benzene Health Effects
Comment; One commenter (XII-D-10) stated that the human epidemiology results
for benzene used by EPA are unacceptable to the scientific community because
no acceptable evidence has been presented of any case of benzene-induced
leukemia outside of the workplace, and because there has been a significant
increase in benzene exposure in America over the last 15 years without a
corresponding significant increase in leukemia cases.
Response: The EPA believes that the existing epidemiological studies clearly
demonstrate an association between benzene exposure and increased risk of
leukemia. The EPA does not believe that this conclusion is now seriously
challenged.
While epidemiological studies have clearly established a dose/response
relationship between cancer in workers and occupational exposure to benzene,
it has not been proven through epidemiological studies that exposure to
benzene at ambient levels causes cancers. Epidemiological studies that have
revealed a statistically significant association between occupational
expo_sure and cancer for substances such as asbestos, coke oven emissions,
vinyl chloride, and ionizing radiation, as well as for benzene, are not as
easily applied to the general public with the inherent number of confounding
variables such as a much more diverse and mobile exposed population, a lack
of consolidated medical records, and limited historical exposure data. Given
the above characteristics, EPA considers it improbable that any
epidemiological association, short of very large increases in cancer, can be
detected among the public with any reasonable certainty. The EPA has taken
the position, shared by other Federal regulatory agencies, that in the
absence of sound scientific evidence to the contrary, carcinogens should be
considered to pose some cancer risk at any exposure level.
Comment; Four commenters (XII-D-04, XII-D-41, XII-D-44, XII-D-216, XII-D-252)
believed that the risk was understated because of use of data from healthy
workers which fail to account for sensitive subpopulations such as children
and the elderly.
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Commenters XII-D-43 and XII-D-207 believed that risk analysis should
consider individual sensitivities. Commenter XII-D-43 referred to the study
by Ott et al. as evidence that some individuals are sensitive and may develop
chronic effects in only a short time (e.g., 18 months of exposure).
Response; As discussed in response to comments on the uncertainty of risk
estimates, this is one of the uncertainties that may cause the risks to be
understated and is one that cannot be quantified with the present under-
standing of biological mechanisms of causation. Since the distribution of
individual susceptibility to leukemia is unknown, the risk to individuals or
subpopulations cannot be considered quantitatively.
General Criticisms of Linearized Multistage Mnripl
Several commenters had criticisms or suggestions for improvement of the
dose/response assessment part of the unit risk estimation procedure. They
are described under the next three comment headings and answered in- the
response that follows. Some commenters criticized the linear multistage
model used by EPA for carcinogenic risk assessment. Two commenters supported
the use of the linear, no threshold model.
Comment: Commenters XH-F-9, XII-D-06, XII-D-38, XII-D-59, XII-D-60, and
XII-D-235, supported by XII-D-27, XII-D-28, XII-D-29, XII-D-32, XII-D-36,
XII-D-55, XII-D-57, XII-D-98, XII-D-101, XII-D-104, XII-D-105, XII-D-197,
XII-D-199, and XII-D-220 objected to the use of the linear, multistage model
and suggested the use of recent scientific advances in pharmacokinetic
models, biologically-based dose/response models, and toxicology information.
Their comments, given below, elaborate further on this.
Commenter XII-D-101 recommended broad application of a generic model
which resulted from the efforts of a subcommittee of the EPA's Risk Assessment
Forum. According to the commenter, this model relies on biological informa-
tion in a two-step mechanism that appears to describe a more biologically
accurate estimate of the likely course of a disease and reduces the risk
below the upper bound. This commenter advocated tracking the distribution of
chemicals through, pharmacokinetic approaches, including measurements of
bioavailability, laboratory bioassays of actual environmental materials, and
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mathematical modeling. The commenter felt this would improve the assessment
of the dosage delivered to an organ in the body that might be damaged by
exposure to a toxic chemical, and of the half-life of chemicals in the body.
Commenter XII-D-59 reasoned that the assumption of low dose linearity is
not biologically plausible for some chemicals.
Commenter XII-D-06 objected to the fact that the EPA Guidelines for
Carcinogenic Risk Assessment's preferred dose/response modeling procedure,
the linearized multistage model, uses only part of the available data --
tumors -- as a function of dose. The commenter stated that pharmacokinetics,
metabolic, and other biological data including species-specific factors, are
not included in the model and do not figure in the risk calculation.
Another commenter (XII-F-9) stated that the limitations of the linear
multistage model are so great that its risk estimates are only useful for
relative risk comparisons and not for absolute measures of risk. Specifically,
the commenter mentioned the model's unresponsiveness to data in the observed
range and the linear constraint placed on the upper bounding procedure.
Given the inherent limitations of any statistically based model for
extrapolating risk to very low exposure levels, the commenter urged the
Administrator to consider all the plausible estimates as part of the "weight
of evidence."
Commenter XII-D-10 pointed out that threshold effects are known to exist
for substances that act by promotion, as well as cessation of effects of some
substances upon cessation of their dosage. In these cases, linear models
would be inappropriate.
Comment; In contrast to the preceding commenters, one commenter (XII-D-04)
did not support anything other than a linear, no threshold model because no
definitive information exists to prove otherwise. Commenter XII-D-216,
representing a group of States, said that his agency's Air Toxics Committee,
in preparing a guidance document for the member States to use in regulating
air toxics, recommended the use of the linear multistage model because of
uncertainties regarding low dose extrapolation.
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Comment: One commenter (XII-D-10) stated that the risk assessment method is
conservative and not pharmacologically sound because EPA assumes that the
total lifetime dose, no matter how or when incurred, is the controlling
factor. The commenter pointed out that this is wrong because any dosage
received less than the length of the latency period before the death of an
individual cannot cause that death. Also, any exposure, no matter how large,
which is incurred after the initiation of a fatal cancer, will not be an
added risk.
Response: The EPA does not agree with the comments that evidence suggesting
a nonlinear dose/response relationship in the observed data is a sufficient
basis to argue that the shape of the dose/response curve is nonlinear at
untested low dose levels. The EPA's view is that linear low-dose
extrapolation is preferred, unless low-dose data and/or mechanism of action
or metabolism data show otherwise. The EPA also believes that it is premature
to assume a threshold effect for benzene due to the lack of understanding
about the mechanism of carcinogenic action. The EPA has elected to use the
linear nonthreshold assumption for the benzene dose/response assessment
because as a matter of science policy, EPA prefers to use assumptions which
will provide risk estimates which are most likely to be exceeded given the
lack of understanding about the mechanism of carcinogenic action. This
choice of models results in an upper bound (i.e., because of the linear
assumption) estimate of leukemia risk to the exposed population.
Other Comments
Comment: The NRDC (XII-D-254) commented that there was not sufficient time
to allow peer review of the Clement report. They said EPA ought not to
implement the many changes in its risk assessment methodology recommended by
API ,in the Clement report outside the normal process for reviewing EPA risk
assessment guidelines. The NRDC cautioned that the Clement report proposed a
number of changes in data and assumptions specific to benzene. One change in
particular would increase the exposure levels previously determined by Rinsky
et al. and that such a proposal needs to be critically reviewed before
accepting these changes.
Response: No response is needed since the URE has not been revised.
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7.3 EXPOSURE ANALYSIS
Many commenters criticized specific assumptions and methods that were a
part of the EPA's exposure analysis, while others had more general
suggestions on how to improve the assessment. The majority of the comments
dealt with specific aspects of the exposure analysis, such as 70-year,
24-hour per day exposure assumption, population location, exposure to multiple
sources, and area source modeling. As with the URE section, underlying many
of these comments was the view that the exposure analysis was either too
conservative or not conservative enough, and therefore, a more plausible or a
more protective assessment is needed. Following the discussion of the very
specific comments are a few comments of a more general nature on the
development of a more plausible exposure analysis.
Exposure Duration and Population Location
Comments described under the following five comment headings are all
addressed together in the one response following them.
Comment; Several commenters (XII-D-06, XII-D-09, XII-D-27, XII-D-32,
XII-D-33, XII-D-34, XII-D-36, XII-D-45, XII-D-57, XII-D-59, XII-D-60,
XII-D-99, XII-D-104, XII-D-105, XII-D-207, XII-D-253, XII-F-9) felt that the
assumption of a 24-hour per day, 70-year exposure was unrealistic. One
commenter (XII-D-45) stated that sources subject to regulation often have
useful production lives of only 15 to 20 years and do not operate continuously.
Two of these commenters (XII-D-34, XII-D-105) advocated basing exposure on
realistic estimates of time spent at residences and actual population trends.
Commenter XII-D-27 recommended that EPA should acknowledge the TEAM study
which indicates the general population at risk normally spends approximately
20 hours per day indoors. One commenter (XII-D-33, supported by XII-D-99)
suggested that EPA assume an 8-hour per day, 35-year exposure in calculating
maximum risk. Another commenter (XII-D-207) said that a 35-year assumption
would still provide a very conservative overestimate of exposure time, there
is only a 0.04 percent chance of a person remaining in the same house his
entire life. Commenter XII-D-60 and XII-D-253 recommended 22 hours per day
and 25 years be used in calculating maximum risks. These are based on a
probability analysis of exposure durations and represent the 95th percentile.
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Comment: Commenter XII-D-60, supported by XII-D-28, XII-D-29, XII-D-33,
XII-D-104, XII-D-105, XII-D-197, XII-D-199, XII-D-220, and Docket
No. A-79-27, Item IX-D-04 advocated conducting a more robust statistical
computation of concentration used for determining the maximum exposure using
the current EPA data. This approach would use upper 95th or 99th percentile
values of the population risk distribution estimates to predict a more
realistic maximum exposure level for each source category.
However, one commenter (XII-D-43) rebutted the argument that 70-year
exposures were overly conservative by pointing out that it may not take a
70-year exposure to develop a chronic effect. Another commenter (XII-D-254)
rebutted API's use of the upper 95th percentile for duration of exposures,
because this would underestimate risks for the 5 percent of the population
that may remain in the house all day. This 5 percent would likely include
infants, the elderly, and the disabled, who are also more sensitive to health
risks than the general population.
Comment: Four commenters favored conservatism regarding the point of maximum
pollutant concentration. Three commenters (XII-D-46, XII-D-219, XII-D-229)
felt that to protect future residents, the maximum individual lifetime risk
(MIR) should be calculated using the maximum offsite pollutant concentration,
regardless of whether there are currently residences at that concentration
point. One of the commenters (XII-D-219) indicated that this idea is in
keeping with the policy of their State air program. Another commenter
(XII-D-51) suggested that to add simplicity and conservatism to the risk
calculation, risks should be calculated based on a standard individual
permanently located at the greatest concentration point on the boundary of
the facility being regulated.
Comment: Commenters XII-D-101 and XII-D-60 (also XII-D-253), supported by
XII-D-28, XII-D-29, XII-D-33, XII-D-104, XII-D-105, XII-D-197, XII-D-199,
XII-D-220, Docket No. A-79-27, Item IX-D-04, and Docket No. A-79-16,
Item VI-E-7, advocated that EPA use site-specific exposure assessments which
incorporate more accurate and relevant information on local conditions in
terms of where residences are located in determining maximum exposure
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concentrations for the MIR. Commenter XII-D-253 provided locations for
130 plants, saying the EPA's coordinates were in error for some of the
plants. Commenter XII-D-60 and XII-D-253 felt that the HEM model's
assumption that residences are only 200 meters away from pollution sources
caused exposure to be overstated because 200 meters is frequently on plant
property. According to Commenter XII-D-253, the vast majority of residences
where maximum exposed individuals live are over 200 meters from the source
and most are well over that distance.
Comment; Commenter XII-D-27 recommended that EPA should identify the
population at risk using current census data.
Response; As noted in the comments, risk estimates are calculated in a
series of steps, and these involve use of simplifying assumptions as well as
estimates of representative data. The EPA recognizes that the assumptions
and procedures used do introduce uncertainty and do affect the quantitative
risk estimates. It is for this (and other) reasons that risk estimates are
not viewed as precise predictors of health risk and are viewed as being a
tool better suited for relative comparisons of pollutants, sources, and
emission controls.
The EPA recognizes that the assumption of 70 years of continuous
exposure constitutes a simplification of actual conditions and represents, in
part, a policy judgment by EPA, but feels that this assumption is preferable
to the alternatives suggested. Although emissions of benzene from industrial
sources would reasonably be expected to change over time, such changes cannot
be predicted with any certainty. In lieu of closing, plants may elect to
replace or even expand their operations and subsequently increase their
emissions. The 70-year exposure duration represents a steady-state emissions
assumption that is consistent with the way in which the measure of
carcinogenic strength (URE) is expressed (i.e., as the probability of
contracting cancer based upon a lifetime [70 year] exposure to a unit
concentration). Constraining the analysis to an "average" plant lifetime
carries the implication that no one could be exposed for a period longer than
the average. Since, by definition, some plants would be expected to emit
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longer than the average, this assumption would tend to underestimate the
possible MIR.
The MIR is a risk measure or indicator that was designed to evaluate the
potential of an emitting plant or source category to cause cancer in the most
exposed individual under the assumptions used in the exposure assessment. It
is not an actuarially measured risk. The EPA is not attempting to estimate
any specific individual's potential of developing the cancer endpoint of
concern (for benzene, myelogenous leukemia). The MIR is calculated by
multiplying the highest annual average concentration to which any person or
group of persons may be exposed by the unit risk factor. Qualifying the
definition of MIR with the statement "to which any person or group of persons
may be exposed," in effect turns what is simply an estimate of the maximum
annual average concentration predicted into an estimate of the highest
potential exposure, or the MIR. The expected MIR is the MIR that one would
expect if the assumptions used to calculate an annual average exposure
persisted unchanged for 70 years, or if these assumptions reflected the
average situation over the 70-year period. Furthermore, annual incidence is
defined as the expected average annual incidence that might result over a
lifetime if the current assumptions represent conditions averaged over
70 years. Incidence also is not actuarially determined.
The EPA agrees that the U.S. population is highly mobile and spends a
proportionally greater amount of time indoors than outside. However,
adjusting the exposure assumptions to constrain the possibility of exposure
to benzene emissions implies that exposure during the periods inside or away
from the residence are zero. In addition, a less-than-lifetime assumption
would also have a proportional impact on the estimated MIR, suggesting that
no individual could be exposed for 70 years. On balance, EPA believes that
the present assumption of continuous exposure is consistent with the
steady-state nature of the analysis and with the stated purpose of making
plausible, if conservative, estimates of the potential health risks. It is
the EPA's opinion that this assumption, while representing in part a policy
judgment by EPA, continues to be preferable to the alternatives suggested,
both in view of the shortcomings of such alternatives and in the absence of
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compelling evidence to the contrary. The complexity of human mobility in
today's society makes it difficult to model exposure with any certainty.
Specifically, it is unknown how long various portions of the population
remain in an area and to what concentrations of benzene they may have been
exposed in other places they have lived. Thus, the simplifying assumption of
a 70-year residence in one location has been made. On a smaller scale, the
exposure model also assumes that people are continuously exposed to the
average ambient benzene concentration at their residence. In reality, people
travel daily within and beyond the local area and they are exposed to
different concentrations at their workplaces, schools, shopping centers, etc.
However, it would be difficult to model local travel and indoor and outdoor
exposures, and any result would be highly uncertain. For instance, even if
were possible for EPA to collect this information over one particular time
period, it may not be representative of population activities in times past
or in the future. It is not known if this approach over or underestimates
actual exposures.
The EPA believes that there is merit to using the simplifying assumption
of 70-year resident immobility. When estimating risk, EPA is concerned about
both the public exposure that is occurring and that could potentially occur.
That group of people exposed to the highest predicted pollutant concentrations
may include individuals, who for a variety of reasons, may spend a large
majority of their lifetimes at a single residence. Presently, EPA does not
have detailed information on those individuals that live near the sources.
Such data, were they available, would not allow EPA to predict the exposure
patterns that high exposure groups may experience in the future.
Other commenters suggested that EPA look at the subpopulation of highly
exposed individuals, a 90 to 95 percent confidence interval on MIR instead of
the "worst case." The EPA has looked into this and has concluded that a
meaningful and consistent measure that represents a high but not the highest
level of exposure would be difficult to calculate based on many of the
reasons described in the uncertainty analysis, namely a lack of data and
uncertainty regarding plant property and where people actually reside. Also,
it is not clear what criteria would be used to determine the particular level
of this estimate of the MIR.
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The same commenters stated that EPA overestimates MIR because the
sources subject to regulation often have useful productive lives of only
15 years and do not operate continuously. The EPA's response is similar to
that given above. The MIR as calculated represents the potential risk to the
most exposed population from plant emissions as that plant has recently been
operating. The EPA agrees that it may not take 70 years of exposure for
cancer to develop so assumptions addressing plant life and population
migration may not be as important as they appear at first glance.
For the benzene source categories, other assumptions used in calculating
the MIR do not give a worst-case estimate of the potential risk. For example,
for most of these benzene source categories the emissions calculated
represent a reasonable estimate of the plant's emission capability based on
recent operations. Also, to avoid an atypical year meteorologically, an
average of several years of meteorological data is used. In addition, the
plants themselves are positioned, to the extent feasible, at their actual
locations; rather than center-city or center-zip code. The MIR could be made
more conservative by tying the measure to a certain point in space from the
plant, or simply accepting the maximum concentration predicted at the plant
site or the plant boundary.
A commenter stated that the 200-meter plant property assumption caused
exposure to be overestimated. The EPA has used the 200-meter fence!ine
assumption routinely to facilitate comparison of the MIR among sources and
source categories. Changes in this assumption have very little impact upon
estimates of population risk (annual incidence) but can significantly affect
the MIR since this measure of risk is normally predicted close in to the
plant/Individual plant boundary information, however, is not readily
available and is often difficult to obtain. Sensitivity analyses indicate
that while the 200-meter assumption may result in an overestimate of the MIR
in some cases, there are also cases where the risk may be underpredicted.
The choice of less sophisticated analyses and need for simplifying
assumptions most often results from the lack of source-specific data. The
collection of such data, which would facilitate more detailed assessments, is
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usually prohibitively expensive. The EPA believes that, in such circum-
stances, assumptions such as the 200-meter fence!ine are a reasonable and
appropriate surrogate.
Since an annual average exposure is used to calculate MIR, migration
does not play a role in determining the conservatism of the estimate. As EPA
is estimating the potential risk from exposure, even if a 70-year average
exposure were calculated, migration would not be considered a significant
factor. By using the 70-year lifetime, EPA calculates a conservative risk
estimate in contrast to other estimates, e.g., annual average risk of traffic
deaths.
Several commenters have suggested that the EPA's risk estimates should
be derived considering actual locations of residential areas. In particular,
one commenter specifically adjusted the benzene equipment leaks exposure
estimates to predict concentrations where people reside. While it is true
that EPA has to varying degrees made this check for some previous NESHAP, EPA
does not believe it is appropriate to do so in the absence of exact informa-
tion on population location. Even with the most sophisticated models,
dispersion modelers are not able, with confidence, to predict that a specific
concentration will occur at a specific point in space and time. They are
confident, within limits, that the maximum concentration predicted will occur
somewhere about the plant at some unspecified time. To require that one or
more residences exist at the point of modeled maximum concentration places
undue emphasis on the capability of the dispersion model to predict that a
specific concentration will occur at a specific location. The EPA regards
the models as accurate to the extent that the predicted maximum concentration
can be expected to occur in the vicinity of the plant. The EPA concludes
that while a rough check of the habitability of the area may be advisable,
insistence on the verification of residences at the specific concentration
point is not technically defensible.
Comment; One commenter (XII-D-60) argued that EPA needs to reexamine its
approach to estimating exposure to introduce more real-world plausibility.
The commenter specifically recommended that, in conjunction with considering
more typical long-term mobility, EPA use the daily activity pattern
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distributions used in ambient standards development. The commenter also
recommended that EPA estimate the concentrations at actual residential
locations.
Response; The EPA has consistently taken the position that the models used
to estimate exposure and risk should be commensurate with the quality and
amount of data available. The national ambient air quality standards (NAAQS)
exposure model (NEM) has been used by EPA exclusively for criteria air
pollutants. Extensive national monitoring networks are established for these
criteria air pollutants that facilitate the identification and evaluation of
microenvironments representative of daily activities. Comparable data are
not available for benzene and the gathering of such data for the much larger
universe of toxic pollutants would be infeasible.
In addition, the health effects associated with exposure to the criteria
pollutants are different from those attributable to benzene. In the criteria
program there is a greater emphasis on the potential for effects from shorter
term exposure and a greater need to evaluate the potential for such
exposures.
While EPA agrees that the incorporation of human activity data would
represent an analytical improvement, this increase in sophistication is not
commensurate with the presently available data, the nature of the effects
evaluated, and the underlying uncertainties in estimating cancer risks from
exposure to benzene.
Emissions Estimates
Comment; Four commenters (XII-D-06, XII-D-32, XII-D-36, XII-D-104) stated
that due to regulation, advances in technology, general concern for safety,
and the likelihood that industries would control emissions to levels below
the standard to ensure compliance, emissions are likely to decrease in the
future; this was not taken into account in the emission estimates.
Response; Responses to comments on emission estimates specific to individual
source categories or plants are contained, as needed, in the sections on each
source category.
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Dispersion Modeling Procedures
Comment; Some commenters thought the dispersion modeling procedures used by
EPA caused risks to be overestimated. One commenter (XII-D-9) stated that
adverse rather than typical dispersion modeling conditions were used. One
commenter (XII-D-99) suggested that since a 70-year exposure was assumed,
that 70 years of meteorological data be used to model the maximum annual
pollutant concentration; the commenter believed this would result in lower
concentrations than estimated using 1 to 5 years of data. One commenter
(XII-D-34) suggested considering pollutant instability in the atmosphere.
Commenters XII-D-43, XII-D-44, and XII-D-254 felt that the assumption of
flat terrain in the exposure modeling was incorrect and could cause exposures
to be underestimated where elevated topography exists.
Response; The EPA agrees that the use of more sophisticated dispersion.
models, where justified, would result in more accurate concentration
estimates. The EPA does not agree, however, that the substitution of a model
such as the Industrial Source Complex Long-Term (ISC-LT) would result in
substantial changes in the estimated risks or that the changes would be only
in a downward direction. In addition, as the commenters noted, the use of
more sophisticated predictive models is often precluded by the input data
requirements, particularly where a large number of emitting sources, or
emission points within the sources, are being assessed. The EPA does not
generally utilize more sophisticated dispersion models unless the input data
are of sufficient quality to ensure that the models' outputs are of better
quality than those available from the screening model in the HEM. For the
benzene sources addressed in this notice, EPA believes that the use of the
HEM screening model was an appropriate choice.
The EPA agrees that the use of site-specific meteorology, where
available in the appropriate amount and format, is superior to the selection
of data from the nearest stability array (STAR) station. In the EPA's
experience, however, such data sets are very limited and only rarely
available. The EPA disagrees that the use of 70 years of meteorological data
to obtain average long-term estimates of risk constitutes an improvement over
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the 1 to 5 years currently used. Even in those few cases in which such a
historical record exists, these data could be no more and perhaps less
representative than the more recent years. Dispersion is modeled using
meteorological data from the nearest STAR stations, which are usually the
nearest recording weather station. Site-specific meteorological data are
almost never available and to obtain such data would be very resource-
intensive. The average of several years (approximately 5) of data is used to
minimize the influence of atypical weather patterns. The EPA disagrees that
70-year averages would necessarily produce lower concentrations than 5-year
averages. The effect would depend on how representative the most recent
5 years of data were of the overall 70-year pattern. Also, 70 years of data
are usually not available at STAR sites. Regardless of the number of years
of meteorological data used in the dispersion modeling, considerable
uncertainty will still remain due to the assumption that the meteorology of
the STAR site is representative of the plant site.
The EPA does consider the stability of compounds in the assessment of
exposure. Data indicate, however, that benzene is relatively stable in the
atmosphere (with a half life of approximately 6 days) and would not degrade
to the extent that there would be an appreciable impact on the exposure and
risk estimates.
The effect of terrain on the estimation of exposure may vary from
site to site. For any one site, the flat terrain assumption may tend to
over- or underestimate exposure. In general, the effect of complex terrain
is less for emissions released relatively close to the ground than for
elevated process vent emissions that have the potential to impact on
hillsides or be affected by building downwash. The EPA agrees that for
sources located in complex terrain where the surrounding topography is at a
higher elevation, exposure may be underestimated; however, the affect may
vary by plant and may be relatively small given the low release heights of
most of the modeled benzene sources.
Comment; Three commenters (XII-D-04, XII-D-43, XII-D-44) felt that the
failure to account for benzene exposure from more than one facility was
incorrect and results in underestimation of risks at some sites where many
plants are located within very close proximity to each other.
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Response; The EPA agrees that Individuals residing in the vicinity of
multiple benzene sources would be exposed to higher levels of benzene than is
represented by the individual point source modeling approach used. The
Increase, however, would be expected to be very small and would not affect
the estimate of population risk since each source would be modeled
individually and the population risks aggregated across the category. The
EPA has concluded from sensitivity analyses that the impact on the MIR
estimates would be very small, since concentration falls off quickly with
distance from the source, and would not, in most cases, affect the rounded
estimate.
The EPA agrees in part that theoretically exposure may be underestimated
if many plants are located in close proximity to each other. First, annual
incidence is not underestimated for those people that are exposed to emissions
from two or more plants is accounted for in the estimation of each plant's
annual incidence. However, MIR can be underestimated. For a significant
underestimation to occur, plants must be situated within several hundred
meters of each other and two or more of these plants must have approximately
the same magnitude of emissions. The odds of this occurring simultaneously
for the plants which determine the MIR for the source category are very
smal 1.
Comment: Commenters XII-D-34 and XII-D-60, supported by XII-D-28, XII-D-29,
XII-D-33, XII-D-104, XII-D-105, XII-D-197, XII-D-199, XII-D-220 and Docket
No. A-79-27, Item IX-D-04 recommended that EPA include the use of area source
modeling for at least the highest MIR plants in the source category since the
HEM model is designed for point source emission calculations and is not
optimal for use in predicting area source emission concentrations. Due to
the high cost of using area source models for all sites, the commenters
recommended that EPA validate the maximum concentration estimates for the
plant sites with the highest MIR values using a suitable area source model
such as the ISC-LT. In addition, Commenter VI-E-7 in Docket No. A-79-16
contended that the risk for one coke by-product recovery plant is
overestimated by a factor of 1.4 due to the HEM's assumption that all
emissions are released from a single location instead of being spatially
distributed. The commenter had modeled that plant's emissions as being
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spatially distributed using the ISC-LT model, which resulted in a lower
predicted risk. The commenter believed that this plant would be
representative of coke by-product plants in general.
Response; The EPA agrees that a more ideal assessment would have used an
area source model and accounted for spatial distribution to estimate the MIR
for source categories such as equipment leaks, benzene storage, and coke
by-product recovery plants. Some of the commenters suggested the use of the
ISC-LT as a possibility. However, EPA disagrees with the commenters'
suggestion that use of the ISC-LT would validate the concentrations estimated
by the HEM dispersion model. Other uncertainties, such as the emission
estimates, and the meteorology would be the same. Furthermore, comparisons
from other projects have shown that HEM and ISC-LT usually agree within a
factor of two or three, and HEM does not always produce the higher value.
As the commenters noted, more sophisticated predictive models are often,
and in this case, were too resource intensive to apply to a large number of
sources. This is especially true for sources with numerous emission points
at each source. The EPA does not generally exercise more sophisticated
dispersion models unless the input data are of sufficient quality to ensure
that the outputs of the sophisticated models are indeed better than those
obtained from the screening model usually used. For benzene, several of the
source categories have many emission points per source, EPA does not have
site-specific characteristics for all facilities in the source categories,
the emission estimates are quite uncertain on a per plant basis, and many
plants have MIR estimates similar to the overall estimate for the source
category. Thus, without expending considerable resources and time, it is
unlikely that use of a more sophisticated model would result in a more
accurate estimate of the MIR.
Use of Actual Measured Air Pollutant Concentrations
Comment: One commenter (XII-D-105) advocated using actual background and
ambient air concentration levels in the exposure assessment, rather than
modeling and worst-case assumptions. One commenter (XII-D-06), supported by
XII-D-32, XII-D-36, and XII-D-104, suggested using monitoring data to verify
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modeled concentration estimates, stating that the EPA's current guidelines on
exposure assessment express a preference for assessments based on measured
data rather than 70-year modeled concentration estimates.
Response: While direct measurement of exposures would appear to be
preferable to modeling, it is not feasible as a routine procedure for NESHAP
development. Factors affecting the feasibility include cost, time,
background concentrations of pollutants, and availability of sufficiently
sensitive analytical methods. In particular, it is neither economically nor
technically feasible to determine or verify exposure in the vicinity of
emitting facilities. It would require siting large numbers of monitors near
each plant to establish concentrations to which all persons living near the
sources are exposed. Exposure will vary with distance and direction from the
plant and the monitoring results could be potentially confounded by
background levels or contributions from other benzene sources. In addition,
monitoring data do not offer a means of predicting future ambient
concentrations resulting from promulgation of a standard. Atmospheric
dispersion models can be used to estimate the directional variations in
exposure and to predict exposure under various emissions control scenarios.
In summary, EPA believes that routine, extensive collection of
monitoring data to verify or substitute for dispersion modeling of emissions
does not represent a feasible approach to assessing exposure to benzene.
Where monitoring data are available, however, EPA does consider such
information in the EPA's deliberative process.
Other Comments
Total Exposure and Risk Analysis
Several commenters felt that the EPA's risk analysis had not accounted
for the total exposure, and thus the total risk, to the population. Some
commenters felt that all routes of benzene exposure had not been accounted
for because only benzene inhalation was considered; other commenters felt
that exposures to pollutants other than benzene had not been factored in.
7-32
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Comment: Three commenters (XII-D-101, XII-D-178, XII-D-203) mentioned the
bioaccumulation of benzene and other carcinogens through the food chain.
Commenters XII-D-10, XII-D-27, XII-D-41, and XII-D-44 advocated that EPA
calculate contributions to exposure by oral, dermal, and inhalation routes,
and determine risk to the exposed population by these three routes.
Comment: Commenters XII-F-12, XII-D-23, XII-D-26, XII-D-35, XII-D-102,
XII-D-130, XII-D-158, XII-D-185, XII-D-200, XII-D-207, XII-D-217, XII-D-230,
and XII-D-252 asked that EPA consider the cumulative effects of exposure to
multiple environmental pollutants.
One agency (XII-D-218) cited the EPA's own science policy as stating
that risks from individual carcinogens are additive, and thus the risk from
benzene sources also emitting other carcinogenic substances is only partially
represented by the risk associated with benzene.
Several commenters (XII-F-7, XII-F-12, XII-F-14, XII-D-14, XII-D-35,
XII-D-41, XII-D-100, XII-D-102, XII-D-130, XII-D-158, XII-D-185, XII-D-203,
XII-D-217, XII-D-252) stated that synergistic effects of various pollutants
had not been taken into account. Commenter XII-D-252 stated that Dr. Irving
Selicoff of the Mt. Sinai Medical Center has written that benzene exposure
will increase damage from radioactivity, even if the exposure to benzene was
many years before.
Commenter XII-D-59, supported by XII-D-29, XII-D-32, XII-D-36, XII-D-55,
XII-D-98, XII-D-104, XII-D-197, XII-D-199 stated that the problem of
significant multiple carcinogen exposures does not appear to widespread, and
that where such exposures occur the impacts are likely to be additive rather
than synergistic. Commenter XII-D-34 stated that epidemiological studies of
benzene-exposed workers, who are also exposed to other chemicals, do not
demonstrate additive or synergistic effects, and that evidence of synergism
exists for only a very few specific chemicals.
Response: Although the principal focus of Section 112 is the regulation of
air emissions of hazardous pollutants, EPA is aware of the potential for some
substances to accumulate in other media or the food chain and result in
indirect exposure. Available data do not indicate that benzene is
7-33
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accumulated by plants, animals, or soil or that significant indirect exposure
is occurring. The EPA recognizes that concurrent exposure to other
pollutants could adversely impact public health; however, no data are
available concerning possible synergistic or antagonistic interactions with
benzene.
7.4 UNCERTAINTY IN RISK ASSESSMENT
Comment; Commenter XII-D-06, supported by several others (XII-D-32,
XII-D-36, and XII-D-104) recommended the use of sensitivity analyses to
illustrate the effect of the assumptions used on the resultant magnitude of
the risk estimate.
Comment: Two commenters (XII-F-3, XII-D-207) presented an alternative method
for estimating the MIR and presenting uncertainty, using techniques that
explicitly incorporate uncertainty and variability into the model
predictions. The commenters described the method as being a simple model
which multiplied together a source term, a dilution factor, an occupancy
factor, fraction of time at site, etc., using Monte Carlo techniques. The
commenters used this method to illustrate the effect of uncertainty on the
potential risk to the most exposed individual posed by radon emissions from a
uranium tailings pile. They illustrated this technique with a bar-graph
which related the probability of a given risk estimate to the area of the
bar. The method produced a maximum risk value about one order of magnitude
smaller than the EPA's "worst-case" estimate. The commenters urged EPA to
use such a method to develop the "best estimate" of risk, along with a
quantitative statement about the uncertainty of the risk, when determining an
acceptable risk level for any NESHAP being developed. In another comment
letter (XII-D-97), the commenter presented a similar simulation of the
uncertainty applied to risk estimates for phosphogypsum stacks. In this
case, the EPA's estimate was a factor of 2 smaller than the highest value
calculated by the commenter. The risk estimated developed by EPA procedures
was described by the commenter as 99.6 percent value and considered to be
very unlikely.
7-34
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Another commenter (XII-D-253) also used Monte Carlo techniques to
account for population mobility and exposure durations in estimating MIR for
the equipment leaks source category. He recommended EPA use similar
methodologies for other source categories.
Response; The EPA has long recognized and attempted to communicate the fact
the quantitative risk estimates contain inherent uncertainties.
Uncertainties arise in all stages of the analysis due to the fact that the
relevant data and understanding of the processes are not complete nor
perfectly accurate and precise. Where data gaps exist, qualitative and
quantitative assumptions are made based on our present understanding of the
biological mechanisms of cancer causation, estimates of air dispersion,
engineering estimates, and other factors. Because of the nature as well as
the number of assumptions made, EPA has in the previous rulemakings only
attempted to quantify part of the uncertainties or to describe the
uncertainties qualitatively. The presentation of quantitative estimates of
only part of the uncertainty has been found to be somewhat misleading because
this part of the uncertainty can be construed as representing the total
uncertainty. Conversely, compounding of the individual uncertainties can
obscure the importance of particular uncertainties.
The comments arguing for quantification of the uncertainty caused EPA to
take a fresh look at the uncertainties in risk estimates. The objective of
this review was to determine whether there are ways to portray the
sensitivity of the risk estimates to changes in assumptions or ways to
quantify the uncertainty. In doing so, the risk calculation procedures were
reviewed and key parameters that significantly affected the estimates were
identified. The feasibility of quantifying the uncertainties was assessed
considering the availability of information on the range and distribution of
values for the key parameters. The simulations submitted by
Commenter XII-D-207 were developed assuming the distribution and variance of
the parameters. In the case of the benzene source categories, EPA does not
think that similar assumptions can be made and documented. In the absence of
such data, any simulation of the combined uncertainties would be misleading
in that it would cause an impression of more knowledge and understanding than
is presently feasible.
7-35
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A synopsis of the parameters considered and the assessment of the
feasibility characterizing the distributions of values sufficiently to
estimate the statistical uncertainty is described below.
Unit Risk Estimate
Major assumptions and factors that significantly affect the derivation
the URE include: (1) the health effect modeled (e.g., the specific cancers
considered); (2) the study or studies used to derive the estimate; (3) the
model used to extrapolate from occupational exposures to the lower dose
levels generally found in the environment; (4) consideration of sensitive
subpopulations; and (5) consideration of synergistic and antagonistic
interactions with other pollutants. At this time, many of these
uncertainties can only be addressed qualitatively because the necessary data
and understanding are not available. Moreover, in the case of some of these
factors the data may never be available. Examples of the information that
may never be available include the distribution of individual
susceptibilities to cancer within the U.S. population and data defining the
response at the low-dose levels. Without additional data and knowledge to
define the likely range of some parameters, combined uncertainty analyses, or
sensitivity analyses, would only provide an illusory benefit.
Emission Estimates and Source Release Parameters
For the majority of the benzene source categories, emission estimates
were derived from emission factors and model plant analyses. Furthermore,
for the purpose of the characterization of the risks and health benefits of
any regulatory alternatives, it was assumed that these conditions persisted
for 70 years. Major factors affecting the uncertainties of the emission
estimates for the benzene source categories include: (1) the
representativeness of the emission factors to actual emission rates and
operations in specific facilities, (2) variations in emission rates among
different facilities and operations in the source category, (3) the
representativeness (and its variation) of the model plants assumed to actual
facilities, and (4) the potential for major changes in source characteristics
and emissions in the future. Very few emission tests have been conducted on
7-36
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benzene sources such as equipment leaks, coke by-product recovery plants, and
storage vessels. None of the available test data is more recent than 1982.
Due to a number of factors such as sparse original database, changes over
time, and (in some cases) the impracticality of testing sources, it is
infeasible to develop a meaningful estimate of the range and frequency
distribution of the uncertainties in the emissions. The potential for future
changes in emissions or in source characteristics, in the vast majority of
cases, is obviously unquantifiable.
Dispersion Modeling
Factors with a significant effect on concentrations predicted by
dispersion modeling include the meteorological data used, the assumption of
urban or rural dispersion, and release height. Meteorological data are
generally not available at specific plant sites, but are available only from
the closest recording weather stations that may or may not be representative
of the meteorology of the plant vicinity. The additional uncertainty
introduced by this assumption is unknown; however, sensitivity analyses have
shown that in some cases it can significantly (e.g., greater than a factor of
10) affect predicted concentrations. The uncertainty or error introduced by
this assumption could only be assessed through collection of several years of
meteorological data at a representative number of sites. Such data and an
analysis are not presently available. The uncertainties of many of the other
parameters (e.g., dispersion coefficients and release heights) can be
quantified to within the general uncertainties of dispersion modeling.
Exposure Assessment
Exposure estimates are primarily affected by the modeled distance to
census block group/enumeration districts (BG/ED) and the plant boundary
assumption. The exposure modeling done in the benzene risk assessments
predominantly calculated the exposure at the BG/ED centroid, and the location
of actual residential areas is unknown. There can be considerable variation
in the population distribution over a BG/ED and the variability among sites
is very large. Information needed to assess the uncertainty in population
locations is only partially available. Maps showing plant property and
7-37
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residential areas are often more than 10 years out of date and many are 20 to
30 years old. Since residential patterns do change, it is likely that
refinements to population locations would introduce more uncertainty than use
of census data presently introduces.
The conclusion drawn from this assessment was that for most steps in the
risk assessment there is insufficient information on the expected range and
statistical distribution of possible values. For other steps there are no
data to define the uncertainty.
There is, however, sufficient experience and understanding to
qualitatively describe the uncertainties and to illustrate representative
ranges of the variability. Table 7-1 lists by parameter typical variations
in the estimates of MIR resulting from use of different assumptions. These
ranges were derived from previous sensitivity analyses of the HEM, literature
information, and professional judgment based on general experience with risk
modeling using HEM and knowledge of the source categories. The variations
shown in Table 7-1 should be viewed as providing a perspective on the
relative magnitude and direction of the uncertainties and not as defining the
entire range for the parameter.
As shown in Table 7-1, there are a number of parameters that can
substantially increase or decrease the estimated risk. It was concluded that
on balance overall the risk estimates are plausible and do not represent the
worst case. This conclusion was drawn recognizing that the assumption of a
70-year, 24-hour per day exposure adds a degree of conservatism.
Comment:
One commenter (XII-D-30) contested the mathematical methods used by EPA
to estimate NESHAP risks, saying they fail to reflect the uncertainty in the
data and experimental methods within the "level of risk" estimation. For
example, dividing one normally-distributed variable by another results in a
number, which the EPA method interprets as a mean value. However, the result
actually is a Cauchy-distributed random variable whose mean does not even
exist. By not using methods which carry the uncertainty through to the
result, EPA may mislead itself and the public.
7-38
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7-39
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Response: While it is technically true that a mean does not exist for these
estimates, standard practice is to assume initially that the variables are
normally distributed and to treat all results as if they are normally
distributed. The risk estimates are not unique in being treated in this
manner.
7.5 REFERENCES
1. Whittemore, A., and J. B. Keller. Quantitative Theories of
Carcinogenesis. SIAH Review, Vol. 20, No. 1, pp. 1-30. January 1978.
2. Hoolgavkar, S., and D. J. Venzon. Two-Event Models for Carcinogenesis:
Incidence Curves for Childhood and Adult Tumors. Mathematical
Biosciences, 47:55-57, 1979.
3. Kipen, H. M., et al. Hematologic Effects of Benzene: A Thirty-Five
Year Longitudinal Study of Rubber Workers. Toxicology and Industrial
Health, Vol. 4, No. 4, pp. 411-430, 1988.
4. Crump, K. S., and B. C. Allen. Quantitative Estimates of Risk of
Leukemia from Occupational Exposure to Benzene. Prepared for
Occupational Safety and Health Administration. May 1984.
7-40
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8.0 FORMATS AND COMPLIANCE PROVISIONS OF STANDARDS
8.1 FORMAT AND COMPLIANCE PROVISIONS OF STANDARDS
Several commenters discussed issues on format of standards and
demonstration of compliance that are applicable to all of the benzene source
categories. These are included below, except for comments on risk-based
waivers or use of risk limits instead of emission limits, which are included
in a separate section.
Comment: Several commenters (XII-D-34, Docket No. A-79-27, Item IX-D-05 and
the CMA (XII-D-59 and XII-D-248) and their supporters) advocated design,
equipment, and work practice standards for equipment leaks and storage, if
standards are needed for these source categories. They preferred these
types of standards to the plantwide emission limit type of standard
proposed to apply to each of the source categories. These commenters and
Commenter XII-D-199 said that the plant emission limits proposed for
equipment leaks under Approaches C and D and storage under Approach D would
be infeasible to enforce. The CMA (XII-D-59) said that demonstration of
continuous compliance is not practical for storage and equipment leaks
sources because in order to measure the emissions one would need to enclose
the processes and monitor building exhaust. These commenters believe
equipment standards are more enforceable for these types of sources.
One commenter (XII-D-199) said that if emission limits are established,
EPA must develop methods of proving compliance. He said that it is extra-
ordinarily difficult to prove compliance and that a plant could be in
compliance without being able to prove it. The commenter pointed out that
the low emission levels from vents, vessels, and equipment leaks which would
be required under Approach D would be difficult to sample accurately, and
that a testing protocol needed to be developed for this situation. Both
commenters XII-D-199 and XII-D-248 raised the point that emission levels may
be below the detection limit, or may be small relative to the variability in
the test methods.
8-1
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The commenter .also protested that it would be impossible to sample every
source in his company's plant, and recommended that some type of statistical
test should be developed.
Response: The EPA agrees that for the equipment leaks and storage emission
sources, and the control techniques applicable to them, emissions cannot be
easily measured. However, the feasibility of emission measurement is not a
relevant concern for the final standards for equipment leaks or for benzene
storage vessels.
Comment: Three commenters (XII-D-34, XII-D-199, XII-D-248) believed that if
emission limit standards are implemented, the limit should be expressed in
terms of a longer averaging time period (e.g., kg/yr instead of kg/day).
Commenter XII-D-34 pointed out that EPA used annual estimates to arrive at a
daily average emission rate, and then in the standards used this daily
average as a maximum permissible amount. The commenter said that to achieve
compliance, sources would actually have to operate far below the level
specified in the regulation to avoid violations. Thus, EPA has added an
additional margin of safety by setting a daily limit. This commenter felt
that the best approach would be to set a maximum amount of benzene that could
be emitted over 1 year. However, he thought it might be impractical to keep
track of the emissions for that period of time, and therefore suggested EPA
could also consider a rolling 30-day average.
Commenter XII-D-248 suggested a way of determining the number of
violations while using an annual emission limit for process vents. He
suggested that plants record daily emissions. If the cumulative annual limit
is exceeded, the highest daily emission should be subtracted from the total
and counted as one violation, and then the next highest subtracted and
counted until the remaining cumulative total is below the annual emission
limit. The number of days subtracted would become the number of violations,
and the basis for'noncompliance findings and penalties.
Response: The final standards for these source categories are not expressed
in terms of emission limits, such as kg/day. Consequently, the length of the
averaging period is no longer an issue in these standards.
8-2
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Comment: The CMA (XII-D-59) and their supporters protested the 90-day period
given in the proposed Approach C and D standards for submitting an operating
and maintenance plan as being unrealistically short.
The CMA also said that the 30-day limit for reporting compliance testing
results was unrealistically short.
Response: The standards proposed under Approach C and D are not being
established and therefore these concerns are now moot.
8.2 RISK-BASED STANDARDS OR WAIVERS
Many commenters suggested that EPA could set a risk-based standard
rather than an emission limit. Others wanted EPA to develop risk-based
waivers if the standard were written in an emission cap format. Or, some
commenters suggested, if EPA performed plant-specific analyses of emissions
and exposures, EPA could set plant-specific emission limits which reflect the
differences in the risk per unit of emissions ratio at the various plants.
Support for a risk-based standard or waiver/site-specific analysis came from
industry, various State agencies or regulatory associations, and environmental/
public interest groups. However, there were some variations in how these
different parties would like to see such standards implemented. State
agencies wanted to ensure that all plants regulated by such a standard would
employ the best available control technology (BACT) and would have risks
below 1 x 10" . Industry wanted to base the level of control for each plant
on a site-specific risk analysis; i.e., plants With low risks may not need to
install controls. These groups also indicated the regulation needed to
include guidance on how to conduct or administrate such a risk-based/
site-specific program. The various ideas they proposed are summarized below.
Comment: Ten commenters, representing the chemical and petroleum industries,
including CMA, (XII-D-29, XII-D-32, XII-D-34, XII-D-36, XII-D-55, XII-D-98,
XII-D-109, XII-D-197, XII-D-199 and XII-F-8) suggested that if EPA sets a
plantwide emission limit for benzene or any other hazardous air pollutant as
a means of achieving a target risk level, EPA should establish a simple
mechanism for granting risk-based waivers. A waiver would allow an individual
plant to exceed the emission limit established for the category as a whole if
8-3
-------
the higher level of emissions at the plant did not cause the target risk
value to be exceeded. These commenters felt this would be desirable because
it might reduce plant closures or production curtailments and would allow the
risk level to be achieved more cost effectively.
Comment: Two commenters (NRDC and the American Lung Association, XII-D-48
and XII-D-100) proposed that a risk-based waiver be developed under
Approach D, but that every facility should also be required to implement
maximum feasible or maximum available control technology. If a plant applied
this technology and still exceeded the emission limit, but complied with the
1 x 10 risk level, the plant would be considered in compliance. This would
allow sources to determine a level of control that is not worst-case driven,
but reflective of actual emissions and demographics at the site.
One State agency (XII-D-229) recommended that, in addition to requiring
the lowest achievable emission reduction (LAER), a site-specific analysis be
used to determine the level of emission/risk reduction to be required at that
site.
Commenters XII-D-46 and XII-D-216 (State and Territorial Air Pollution
Program Administrators/Association of Local Air Pollution Control Officials
[STAPPA/ALAPCO] and Northeast States for Coordinated Air Use Management
[NESCAUM]) suggested facilities should only be required to adopt controls
beyond BACT until the 1 x 10"6 risk level is achieved. Achievement could be
determined through site-specific analysis and risk-modeling. Three commenters
(XII-D-46, XII-D-48 and XII-D-100) proposed that this risk cut-off or waiver
(as opposed to the emission cap) would prevent many of the closures or
curtailments which EPA had predicted under Approaches C or D.
Comment: Some groups suggested standards be expressed in terms of risk
rather than emission limits, and that site-specific modeling be used to
determine compliance. One State agency (XII-D-40) asked EPA to consider
site-specific modeling analyses by sources to comply with the designated risk
targets. Another State (Rhode Island Division of Air and Hazardous
Materials, XII-D-219) also preferred a risk target approach, suggesting it
would not involve substantial extra work because each source would have to be
modeled anyway.
8-4
-------
The Department of the Navy (XII-D-51) recommended that a risk-based
limit be promulgated, along with the method required to determine the risk.
The Department reasoned that an emission cap, which is actually based on a
risk target, might actually result in greater-than-target-risk to a population
residing downwind from a benzene facility.
Comment: Some commenters requested that EPA develop firm guidance on the
site-specific modeling and review necessary to administer a risk-based
program. One of these commenters (XII-D-100) suggested replicable protocols
would need to be developed by EPA to manage this waiver process. He indicated
that the EPA's review of waivers should be funded through applicant fees.
Commenter XII-D-51 also said EPA should establish a method to determine the
site-specific risks.
Other commenters (XII-D-34 and XII-D-219) believed EPA could develop
guidance on modeling procedures fairly quickly. One commenter (XII-D-34)
claimed meteorologic data, location of the nearest residences, and stack
parameters are readily available. He also suggested that EPA could review
risk modeling already submitted by many facilities to State agencies,
determine which models are acceptable, and set a range of acceptable
assumptions based on this review. Commenter XII-D-219 also noted that some
States have already attempted to establish a protocol to insure consistent
modeling.
Related to the site-specific analysis of risk, STAPPA/ALAPCO, NESCAUM
and two States (XII-D-46, XII-D-216, XII-D-219 and XII-D-229) strongly
advised that the calculation of risk at a given site be based on the highest
concentration at the boundary or the maximum impact.
Comment: On the other hand, the API (XII-D-60) argued that standards
expressed in terms of MIR might not be feasible because only large sources
could afford to do the risk modeling calculations necessary to prove
compliance.
Response: Under the final policy developed for NESHAP, the acceptability of
risks is judged considering all health and risk information and is not
determined solely on the basis of one particular risk parameter. In the
8-5
-------
second step decisions, EPA selected standards that were based on application
of specific equipment and work practices. Consequently, the standards do not
correspond to a single risk level, and it is not possible to define a single
risk level that provides equivalent protection on a nationwide basis.
Therefore, the various recommendations to use risk-based standards are no
longer pertinent.
8.3 MISCELLANEOUS COMMENTS ON REGULATIONS
Comments on sources regulated and other miscellaneous comments on
standards applicable to multiple source categories are included here.
Comment; Commenter XII-D-36 found it difficult to understand why EPA was
going to regulate certain stationary sources of benzene, possibly with severe
economic impacts and uncertain health benefits, when it was not taking into
account major sources of benzene (e.g., automobile exhaust and refueling
operations), to which most people in this country are exposed on a daily
basis.
Response: The focus of Section 112 of the CAA is on stationary sources; the
other sources mentioned by the commenter are dealt with under other provisions
of the CAA. Since all of these sources contribute to the atmospheric
concentrations of benzene, it is appropriate to use all of the available
regulatory tools, including the applicable CAA sections, to address the
pollution problems caused by these sources.
Comment: One commenter (XII-D-32) objected to the definition of "plant" in
the emission limit standards proposed for benzene source categories under
Approaches C and D. The commenter felt that this definition, and the
standards based on it, would favor small plants at different sites over a
large multi-unit plant. The commenter recommended that if Approach A is
chosen, that this definition not be included in the standards.
Response; The plantwide emission standards proposed under Approaches C and D
are not being implemented as final standards. The final standards consist of
equipment, design, and work practice requirements; these do not provide an
advantage to small plants relative to large multi-unit plants.
8-6
-------
APPENDIX A
LIST OF COMMENTERS
A-l
-------
NUMBER
BENZENE HEALTH EFFECTS
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Garments Received After the Proposal
DATE REC'D
IN CDS
XII-D-Ol 09-07-88
XII-D-02 09-09-88
XII-D-03 09-13-88
XII-D-04 09-12-88
XII-D-05 09-21-88
XII-D-06 09-19-88
XII-D-07 09-22-88
XII-D-08 09-27-88
XII-D-09 09-27-88
XII-D-10 09-28-88
XII-D-11 09-28-88
XII-D-12 09-28-88
XII-D-13 09-28-88
XII-D-14 09-28-88
XII-D-15 09-28-88
XII-D-16 09-28-88
XII-D-17 AUG/SEP
XII-D-18 09-29-88
DATE OF
COMMENTER etc. DOCUMENT
New Mexico Health & Env. Dept., Millicent Eidson 08-31-88
Sealed Air Corporation, Nelson E. Malwitz 09-02-88
CANAH Coalition for Alternatives in Nutrition 09-07-88
'and Healthcare, Inc., Catherine J. Frcmpovich
Brandt Mannchen (Private Citizen) Houston, TX 09-03-88
Environmental Research Foundation, Peter Montague 09-17-88
Cleary Gottlieb Steen & Hamilton, Donald Stevenson 09-20-88
(Counsel for) AIHC American Industrial Health
Council,
Morris Highlands Audubon Society, Charles Lenchitz 09-19-88
Kentucky Resources Council, Ton FitzGerald 09-21-88
Michigan Dept. of Natural Resources, Robert Miller 09-23-88
John T. Barr (Private Citzen) Easley, SC 09-21-88
Silicon Valley Toxics Coalition, Ted Smith 09-21-88
Vermonters Organized tor Clean Up (VOC), 09-21-88
Theresa Freeman
ICATW Ironbound Cotmittee Against Toxic Waste, 09-21-88
Arnold Cohen
OCAW Oil, Chemical & Atomic Workers, Richard Miller 09-21-88
W.A.T.E.R., Dorothy M. Lang 09-22-88
Seeber, Bowkley, Greb & Zelante, Morris Greb 09-21-88
Letters/post cards from Private Citizens dated
August 13 thru September 24 (38 Letters)
Dr. & Mrs. T.J. Voneida (private citizens) 09-23-88
Kent, Ohio
A-2
-------
XII-D-32
XII-D-33
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-19
XII-D-20
XII-D-21
XII-D-22
XII-D-23
XII-D-24
XII-D-25
XII-D-26
XII-D- 27
XII-D-28
XII-D-29
XII-D-30
XII-D-31
DATE REC'D
IN CDS
09-29-88
09-29-88
09-29-88
09-29-88
09-29-88
09-29-88
09-29-88
09-29-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
COMMENTER etc.
Vida Roth (private citizen) Bloonington, IN
Michael G. Bennett (private citizen) Dover, NH
Petition f ran members of the faculty of Oliver
Street School in Newark, NJ (37 names)
Bracewell & Patterson, William A. Anderson, II
(Counsel for: STERLING CHEMICALS)
Township of Egg Harbor, Maria T. Bchle;
Letter w/attachmente.
National Coal Association, David C. Banand
Letter addressed to Lee M. Thomas
Rowan Environmental Action Partners, Patricia Link
New York City Coalition to Stop Food Irradiation,
Michael C. Colby
American Coke and Coal Chemicals Institute,
Mark T. Engle (Same ccranent: A-79-16 IV-D-52
and A-79-27 DC-D-01)
Citgo Petroleum Corp. , w. James McCarthy
Texaco Inc., u.H. Henderson, Jr.
BP America Inc. , Allen R. Ellett
Beveridge & Diamond, Don G. Scroggin (Counsel for
DATE OF
DOC.
N/D
N/D
•N/D
09-29-88
09-21-88
09-28-88
09-26-88
09-26-88
N/D
09-30-88
09-28-88
09-30-88
10-03-88
10-03-88
10-03-88
Monsanto Ccmpany, Charles D. Malloch; Letter w/
attachment , u
XII-D-34 10-03-88
Wilmer Cutler & Pickering, NeiljfeL King (Counsel
for AMERICAN IRON AND STEEILflNbUSTR^; Lettr w/
attachment (same corcnent A-79~±67'w-D-53)
Dew Chemical U.S.A., R.s. Rose & F. Hoerger;
Letter w/attachment
09-30-88
10-03-88
10-03-88
A-3
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comnents Received After the Proposal
NUMBER
XII-D-35
XII-D-36
XII-D-37
XII-D-38
XII-D-39
XII-D-40
XII-D-41
XII-D-42
XII-D-43
XII-D-44
XII-D-45
XII-D-46
XII-D-47
XII-D-48
XII-D-49
XII-D-50
DATE REC'D
IN CDS
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
COMMENTER etc.
Gary Martin Cohen, PH.D (Highland Park, NJ)
(request tor an extension of deadline)
Union Carbide Corporation, Robert T. Jackson •
Letter w/attachment
Geiman Sciences, Charles Gelman
CEOH Consultants in Epidemiology & Occupational
Health, Inc. ; Letter w/attachment
Accord Research and Educational Associates, Inc.
Richard Piccioni
Connecticut Department of Health Services, ''
David R. Brown & Hari Rao
Larry E. Fink (private citizen) Falls Church, VA
Letter w/attachment
Reitman Parsonnet Maisel & Duggan, Bennet D.
Zurofsky
Colorado Department of Health, Bradley J. Beckham
Coranonwealth of Massachusetts, Elizabeth Anne
Bourque; Letter w/attachment
Kerr-McGee Corporation, Edwin T. Still and
John C. S tauter
Stappa/Alapco, S. William Becker; Letter w/attach.
Hunton & Williams, F. William Brownell (Counsel for
Utility Air Regulatory Group; Letter w/attachment
American Lung Association, Conrad J. Mason
Letter w/attachment
ASARCO Inc. , Donald A. Robbins
HSIA Halogenated Solvents Industry Alliance,
DATE OF
DOC.
09-30-88
10-03-88
09-29-88
10-03-88
10-01-88
09-30-88
10-03-88
09-26-88
09-30-88
09-30-88
10-03-88
09-30-88
10-03-88
09-30-88
10-03-88
10-03-88
Paul A. Cannier; Letter w/attachments
A-4
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
^•^^•^•^^H^^
XII-D-51
XII-D-52
XII-D-53
XII-D-54
XII-D-55
XII-D-56
XII-D-57
XII-D-58
XII-D-59
XII-D-60
XII-D-61
XII-D-62
XII-D-63
XII-D-64
XII-D-65
XII-D-66
XII-D-67
XII-D-68
DATE REC'D
IN CDS
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-U3-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
COMMENTER etc.
Department of the Navy, Richard A. Guida
Oak Ridge National Laboratory, Curtis C. Travis
Letter w/attachment
Middle south Utilities System, George E. White-
Letter w/attachment
Commonwealth of Massachusetts, Diane M. Maganaro-
Letter w/attachment
Kodak Company, j.c. Edwards
Environmental Conservation Board of the Graphic
Communications Industries, Fred Rosenblocm
Motor Vehicle Manufacturers Association,
Fred W. Bowditch; Letter w/attachment
Regional Air Pollution Control Agency, John A. Paul
CMA Chemical Manufacturing Company, Geraldine V
Cox, et al., Letter w/attachmsnts (same materials
also put into Dockets A-79-27; A-79-49; & A-80-14)
API American Petroleum Institute, Terry F. Yosie-
Letter w/attachment (same material also put into
Dockets A-79-16; A-79-27; A-79-49 ; & A-80-14)
C.E. Atnip (private citizens), Calvert City, KY
Stephen C. Sawtner (private citizen) Westfield, NJ
Ralph Long (private citizen)
Patsy Thureatt (private citizen) Calvert City, KY
Keari Tony (private citizen)
Linda and Gregory Ward (private citizens)
Donna Hayes (private citizen) Bunker, MO
Harry Hayes (private citizen) Bunker, MO
DATE OF
DOC.
10-03-88
09-16-88
09-30-88
09-30-88
09-29-88
10-00-88
09-28-88
09-30-88
10-03-88
10-03-88
09-24-88
09-21-88
09-29-88
09-24-88
09-26-88
09-26-88
09-26-88
09-26-88
A-5
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-69
XII-D-70
XII-D-71
XII-D-72
XII-D-73
XII-D-74
XII-D-75
XII-D-76
XII-D-77
XII-D-78
XII-D-79
XII-D-80
XII-D-81
XII-D-82
XII-D-83
XII-I>84
XII-D-85
XII-D-86
XII-D-87
XII-D-88
XII-D-89
DATE REC'D
IN CDS
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-8'8
10-03-88
10-03-88
10-03-88
OOMMENTER etc.
Patricia Link (private citizen) Cleveland, NC
Charles Leiden (private citizen) Altoona, PA
Neil & Virginia Bonyor (private citizens)
Great Meadows, NJ
Verble Dullinger (private citizen) Bolivar, IN
Dan & Rosemary Waldron (private citizens)
Austin, TX
Sherry L. Smith (private citizen) Austin, TX
Clay Carter (private citizen) Birmingham, AL
Donald L. Shepherd (private citizen) Salem, VA
Thonas M. Strode (private citizen)
New Port Richey, FL
Bettina Redway (private citizen) Sacto, CA
Donna Klewer (private citizen) Chesterton, IN
Joan Candalino (private citizen) New Port Richey
Denise G. D'Atrio (private citizen) Belleville,
Cecilia Keller (private citizen) Bolivar, TN
Don Clark (private citizen) Mutley, NJ
Jack I. Stern (private citizen) Glen Ridge, NJ
James Stewart (private citizen) Pottsboro, NC
Kathy English (private citizen) Bolivar, TN
Charles E. Holzer (private citizen) Gallipolis,
Henry M. Harris (private citizen) Ashville, NC
Ray & Carolyn Ervin (private citizens) Bolivar,
DATE; OF
DOC.
09-26-88
N/D
09-28-b8
09-26-88
N/D
N/D
N/D
09-28-88
09-26-88
09-26-88
09-25-88
, FL 9-26-88
NJ 09-23-88
N/D
09-22-88
09-22-88
09-27-88
09-26-88
OH 09-27-88
09-25-88
TN 09-26-88
A-6
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comments Received After the
NUMBER
XII-D-90
XII-D-91
XII-D-92
XH-D-93
XII-D-94
XII-D-95
XII-D-96'
XII-D-97 10-04-88
XII-D-98 10-04-88
XII-D-99 10-04-88
XII-D-100 10-04-88
XII-D-101 10-04-88
XII-D-102 10-04-88
XII-D-103 10-04-88
XII-D-104 10-04-88
XII-D-105 10-04-88
XII-D-106 ' 10-04-88"
XII-D-107 10-04-88
XII-D-108 10-04-88
DATE REC'D
IN CDS
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-03-88
10-04-88
COMMENTER etc.
ARISE, Edmund F. Benson (private citizen) Maimi,
Lawrence G. Hunter (private citizen)
Patsy Hunter (private citizen)
Martha A. Goldbach (private citizen) Evansville,
J. Dwaine Phi fer (private citizen) Cleveland, NC
John White (private citizen) Black, MO
Department of Energy, Raymond P. Berube; Letter
nATr nrr
DA 1 t OF
DOC.
FL 9-25-88
09-26-88
09-26-88
IN 09-25-88
09-19-88
N/D
10-03-88
The Fertilizer Institute, Gary D. Myers; Letter 10-03-88
w/attachment (same material also put into
Dockets A-79-16; A-79-27; A-79-49; & A-80-14)
Cain Chemical Inc., C.M. Moffitt 10-03-88
Bethlehem Steel Corporation, David M. Anderson 09-30-88
(duplicate of A-79-16, IV-D-56)
NRDC Natural Resources Defense Council, David D. 10-03-88
Doniger; Letter w/attachment
Kaiser Aluminum & Chemical Corp., L.M. Rapp 10-03-88
Letter w/attachment w
Food and Water Inc., Judith H. Johnsrud; Letter 09-27-88
w/attachment
GATX Terminals Corp., R.W. Bogan 09-29-88
Amoco Corporation, Walter R. Quanstrom 10-03-88
Chevron Environmental Health Center, Inc., 10-03-88
William S. Bosan
Ohio Council of Skin & Scuba Divers, Inc., 09-29-88
Nathan Shaffer
University of Southwestern Louisiana, Sheryl Moore 09-29-88
Environmental Planning Lobby, Larry Shapiro, 09-30-88
Anne Rabe, and Leslie Dame
A-7
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-109
XII-D-110
XII-D-111
XII-D-112
XII-D-113
XII-D-114
XII-D-115
XII-D-116
XII-D-117
XII-D-118
XII-D-119
XII-D-120
XII-D-121
XII-D-122
XII-D-123
XII-D-124
XII-D-125
XII-D-126
XII-D-127
XII-D-128 '
XII-D-129
XII-D-130
DATE REC'D
IN CDS
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
COMMENTER etc.
Shenango Inc., James R. Zwikl
Lin Kaa-tz Chary (private citizen) Gary, IN
CANE, Marvin I. Lewis (private citizen)
Associated Industries of Missouri, Brad Jones
Lillian Robinson (private citizen) Fremont, OH
Maxine Laugh (private citizen) Bunker, MO
Bonnie Mertzlufft (private citizen) Bunker, MO
Glenneda King (private citizen) Acme, PA
Mr. & Mrs. John H. MacGovoan (private citizen)
~ i*>* ngs ionn, — tri r\j. KiV>x»s'V-«><_»jv-k^ «*-i.
Sister Aloise Boone (private citizen) Benton KY
Laurence Frederick (private citizen) Hermann, MO
Carol Shonk (private citizen) Wichita, KS
Esther M. Reynolds (private citizen) Linn, MO
Donna Hinder! iter (private citizen) Wichita, KS
NY State Congress of Parents & Teachers Inc.,
Elsa Ford
Arthur R. Woodke (private citizen) Tinley Park, IL
Petition (30 names) private citizens
Jim Ruiz (private citizen) Deerfield, IL
Virginia Melvin (private citizen) Woodstock, IL
Virginia Shanahan (private citizen) Boulder, CO
Jewell Marvin (private citizen) Bolviar, TN
Native Americans for a Clean Environment,
Jessie DeerlnWater
A-8
DATE OF
DOC.
09-30-88
09-26-88
N/fD
10-04-88
09-30-88
09-27-88
09-24-88
09-30-88
09-23-88
N/D
N/D
09-28-88
N/D
09-29-88
09-30-88
09-27-88
N/D
N//D
09-26-88
09-28-88
N/D
09-29-88
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-131
XII-D-132
XII-D-133
XII-D-134
XII-D-135
XII-D-136
XII-D-137
XII-D-138
XII-D-139
XII-D-140
XII-D-141
XII-D-142
XII-D-143
XII-D-144
XII-D-145
XII-D-146
XII-D-147
XII-D-148
XII-D-149
XII-D-150
XII-D-151'
XII-D-152
XII-D-153
DATE REC'D
IN CDS
1 0-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88.
1 0-04-88
10-04-88
1 0-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
COMMENTER etc.
Carol A. Unertl (private citizen) Doriners Groe
Joseph Nardone (private citizen) Newark, NJ
Renee S. Gagnor (private citizen) Chicago, IL
Cnythia Folke (private citizen) Oak Forest, IL
Carmela Foster (private citizen) Chicago, IL
Ilyasah Javett (private citizen) Chicago, IL
Vincent Mertzlufft (private citizen) Bunker, MO
Richard Murzyn { private citizen) Griffith, IN
Rebecca Leonard (private citizen) Chicago, IL
Steven 01 sson (private citizen) Glen Ellyn, IL
William F. Mosca (private citizen) Evanston, IL
Chris Stodder (private citizen) Chicago, IL
Charlotte Keller (private citizen) Jones Mills,
Clifford Patts (private citizen) St. Anne, IL
Julie L. Levensin (private citizen) Northbrook,
Thomas Young (private citizen) Chicago, IL
Paul R. Evans (private citizen) Chicago, IL
Catherine M. Cameron (private citizen) Goldston,
Elisabeth R. Br (private citizen) Evanston,
Mark Stinson (private citizen) Chicago, IL
Ann B. lafrate (private citizen) Everett, MA
Merle Pearson (private citizen) Fremont, OH
George W. Brint (private citizen) Bolivar, TN
DATE OF
DOC.
, IL 9-29-88
09-28-88
09-29-88
09-29-88
09-29-88
N/D
09-24-88
09-25-88
09-29-88
09-29-88
09-29-88
N/D
PA 09-30-88
09-29-88
IL N/D
09-29-88
09-29-88
NC 9-29-88
IL 09-30-88
N/D
09-27-88
09-29-88
09-29-88
A-9
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comments Received After the Proposal
NUMBER
XII-D-154
XII-D-155
XII-D-156
XII-D-157
XII-D-158
XII-D-159
XII-D-160
XII-D-161
XII-D-162
XII-D-163
XII-D-164
XII-D-165
XII-D-166
XIi-D-167
XII-D-168
XII-D-169
XII-D-170
XII-D-171
XII-D-172
XII-D-173
i
XII-D-174
XII-D-175
XII-D-176
DATE REC'D
IN CDS
10-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
10-04-88
1 0-04-88
10-04-88
1 0-04-88
10-04-88
10-04-88
10-04-88
1 0-04-88
COMMENTER etc.
Glenneda Gearhart (private citizen) Acme, PA
Kurt Palmer (private citizen) Chicago, IL
Joe and Jane Chaplin (private citizens)
Private Citizen (no name) Bunker, MO
Central Pennsylvania Citizens for Survival,
Gladys Zelinsky (Chairperson)
Kevin Christinat (private citizen) Wichita, KS
David Garrison (private citizen)
Leone Beavers (private citizen)
DATE OF
DOC.
N/D
N/D
09-30-88
09-2-7-88
09-29-88
09-29-88
09-29-88
N/D
Billie Jean Pattrett (private citizen) Bunker, MO 09-26-88
Catherine Lippert (private citizen) Kansas City,
Gary Schwochow (private citizen) Fremont, OH
Ewell F. McKinnie (private citizen) Middleton, TN
Private Citizen, Duson, LA
Kathryn Pearson (private citizen) Fremont, OH
Mr & Mrs Monroe Barton (private citizens) Bunker,
J.A. Ellis (private citizen) Chicago, IL
Nancy E. Bishop (private citizen) Chicago, IL
Kaye Sheets (private citizen) Cleveland, NC
Milen Hayes (private citizen) Chicago, IL
Chad Conzelmann (private citizen) Lafayette, LA
Sandra S. Brauer (private citizen)
Lincoln D. Rogala (private citizen) Wheaton, IL
Robert J. Osswald (private citizen) Quincy, IL
A-10
MO 9-25-88
09-28-88
09-29-88
09-25-88
09-28-88
MO 9-27-88
N/D
09-29-88
09-29-88
09-29-88
N/D
09-28-88
09-28-88
09-29-88
-------
-
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comments Received After th* Proposal
NUMBER
XII-D-177
XII-D-178
XII-D-179
XII-D-180
XII-D-181
XII-D-182
XII-D-183
XII-D-184
XII-D-185
XII-D-186
XII-D-187
XII-D-188
XII-D-189
XII-D-190
XII-D-191
XII-D-192
XII-D-193
XII-D-194
XII-D-195
XII-D-196
DATE REC'D
IN CDS
1 0-04-88 .
10-04-88
10-04-88
10-04-88
1 0-04-88
1 0-04-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
10-05-88
COMMENTER etc.
Paul Conzelmann (private citizen) Lafayette, LA
Debra L. Adams (private citizen) Acme, .PA
Donna Suan (private citizen) Boulder* CO
A] & Lyn Wilson along w/ 9 additional signatures
(private citizens) Salisbury, NC
Standard Form Letter submitted separately by
20 people (private citizens)
Standard Form Letter favoring Method D, submitted
separately by 11 people (private citizens)
Carolyn & Charles Merol (private citizens) '
Dillsboro, NC
Norma B. Kirk (private citizen) Bolivar, TN
Regina C. Rowan (private citizen) Hyde Park, MA
Patty Clary, CAT Californians for Alternatives
to Toxics (private citizen) Arcata, CA
Beverly Braverman (private citizen) Acme, PA
Mary Roy (private citizen) Amherst NH
Carol Oldershaw (private citizen) Chicago, IL
Gregory & Donna Smart (private citizens)
Newport, NH
Pete Sultatos (private citizen) Marietta, PA
Hazel M. Gibbs (private citizen) Fremont, OH
Barbara S. Patrick (private citizen) Esopus, NY
Florence M. Sizemore (private citizen) Bunker, MO
Louis Blumberg (private citizen) San Francisco, CA
Vicki Shirey (private citizen) Mayport, PA
r\ *T*r* r*r~
DATE OF
N/D
09-28-88-^
09-28-88
N/D
N/D
N/D
09-26-88
N/D
09-30-88
09-29-88
N/D
10-02-88
N/D
09-27-88
10-01-88
09-29-88
09-24-88
09-30-88
09-29-88
10-03-88
A-ll
-------
Docket No. OAQPS 79-3, Part I
NUMBER
XII-D-200
XII-D-201
XII-D-202
XII-D-204
XII-D-205
XII-D-206
XII-D-207
XII-D-208
XII-D-209
XII-D-210
XII-D-211
XII-D-212
XII-D-213
XII-D-214
Subcategory XII-D
Additional Comments Received After the Proposal
DATE REG'D
IN CDS
XII-D-197 10-05-88
XII-D-198 10-06-88
XII-D-199 10-06-88
10-07-88
10-07-88
10-07-88
XII-D-203 10-07-88
10-07-88
10-07-88
10-07-88
10-07-88
10-11-88
10-11-88
10-11-88
10-11-88
10-11-88
10-11-88
10-11-88
COHMENTER etc.
Keller and Heckman, Peter L. de la Cruz (Counsel
for) SPI Society of the Plastics Industry, Inc.;
Letter w/attachment
Kerotest Manufacturing Corp., Richard W. Conley
Letter w/attachment addressed to Eileen Claussen
(EPA) (duplicate of A-79-27, IX-D-07)
DATE OF
POTT
10-03-88
09-30-88
Bracewell & Patterson, William A. Anderson (Counsel 10-03-88
for) Sterling Chemicals, Inc.; Letter w/attach.
International Inst. of Concern for Public Health 10-04-88
Rosendale Environmental Commission, Manna J. Greene 10-03-88
Bountiful Gardens, Charles March, Paula Stobbe, 09-27-88
and Katherine S. Hester
Maryland Nuclear Safety Coalitition, Patricia 10-03-88
Birnie; Letter w/ attachment
Union Camp Corp., R. Thome 10-03-88
Handy & Harman, John C. Bullock 10-03-88
UMD University of Medicine & Dentistry of N.J., 09-30-88
Bernard D. Goldstein; Letter w/attachment
AMC American Mining Congress, James E. Gil Christ; 10-03-88
Letter w/attachment addressed to Lee M. Thomas
Marvin I. Lewis (private citizen) Phila., PA N/D
Letter addressed to Lee Thomas
American Chemical Society, Gordon Nelson 10-03-88
Walter & Rose Lubin (private citizens) Par!in, NJ 09-30-88
Dorothy Ingline (private citizen) 10-07-88
Atlantic Highlands, NJ
Gibson & Robbins-Penniman, Joseph M.Reidy 10-03-88
Lee Gratwick (private citizen) Pavilion, NY 10-03-88
David A. Murray (private citizen) Par!in, NJ 09-30-88
A-12
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-215
XII-D-216
XII-D-217
XII-D-218
XII-D-219
XII-D-220
XII-D-221
XII-D-222
XII-D-223
XII-D-224
XII-D-225
XII-D-226
XII-D-227
DATE REC'D
IN CDS
10-13-88
10-13-88
10-14-88
10-14-88
10-14-88
10-19-88
10-19-88
10-19-88
10-19-88
10-24-88
10-24-88
10-31-88
10-31-88
«
COMMENTER etc.
API American Petroleum Institute, 6. William Frick
Letter w/attachments
NESCAUM Northeast States for Coordinated Air Use
Management, Michael J. Bradley
Environmental Coalition on Nuclear Power,
L.J. Glicenstein; Letter w/attachment
EPA, Region VIII (Denver) Risk Assessment Workgroup
James B. Lehn p
Rhode Island and Providence Plantations, Division
of Air and Hazardous Materials, Thomas Ge'tz and
Barbara Morin
Chevron Corporation, R.L. Arscott; Letter w/attach.
Burton L. Appleton (private citizen) Alexandria, VA
Max Lyon (private citizen) Palo Alto, CA
Richard L. Christie (private citizen) Moab, UT
Colorado Department of Health, Jean Terry
ASTHO Association of State and Territorial
Health Officials, Thomas Vernon
Evan Handler (private citizen) New York, NY
NIRS Nuclear Information and Resource Service,
Diane D'Arrigo; Letter addressed'to Jack Farmer
EPA/RTP, NC
DATE OF
DOC.
10-12-88
10-03-88
09-29-88
10-03-88
N/D
10-12-88
10-17-88
10-12-88
10-03-88
10-14-88
10-19-88
09-02-88
09-28-88
XII-D-228 10-31-88
XII-D-229 10-31-*
MNSC Maryland Nuclear Safety Coalition, 10-02-88
Patricia Birnie; Letter w/attachment addressed
EPA/RTP, N.C.
New Jersey Department of Environmental Protection 10-05-88
Jorge H. Berkowitz; Letter addressed to
Robert L. Ajax (EPA, RTP)
XII-D-230 10-04-88 Martha C. Cottrell (private citizen) New York, NY 09-26-88
A-13
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comments Received After the Proposal
NUMBER
XII-D-231
XII-D-232
XII-D-234
XII-D-235
XII-D-236
XII-D-237
XII-D-238
XII-D-239
XII-D-240
XII-D-242
XII-D-243
XII-D-244
XII-D-245
XII-D-246
DATE REC'D
IN CDS
10-31-88
10-31-88
XII-D-233 11-02-88
11-08-88
11-10-88
12-02-88
12-02-88
12-02-88
12-02-88
12-07-88
XII-D-241 12-19-88
12-30-88
01-03-89
01-13-89
01-26-89
01-30-89
COMMENTER etc.
Lu Mitterman (private citizen) Chicago, IL
Hunton & Williams, F. William Browne!! (Counsel
for UTILITY AIR REGULATORY GROUP); Letter
addressed to Lee M. Thomas [Enclosure may be found
w/Document XII-D-47J
/
AMC American Mining Congress, James E. Gilchrist
Letter w/attachment addressed to Lee M. Thomas
(supplemental comments to Document XII-D-207)
U.S. Department of Energy, John C. Tseng; Letter
w/attachment
API American Paper Institute, John L. Festa &
Robert C. Kaufmann; Letter w/attachment
North Carolina Citizens Research Group
David Shutan (Private Citizen) Hamden, CT
Marine & Beverly Zimmerman (private citizens)
AMC American Mining Congress; Letter w/attach.
ASTHO Association of State and Territorial Health
Officials, Thomas Vernon
CEOH Consultants in Epidemiology & Occupational
Health, Inc.
Marvin I. Lewis (private citizen) Phila., PA
Marta D. Harting, Baltimore, MD
Perkins Coie, Anthony J. Thompson; Letter
w/attachment
Shelley Nelkens (private citizen) Antrim, NH
AIHC American Industrial Health Council,
Donald E. Stevenson, Letter w/attachment
XII-D-247 01-30-89 Sterling Chemicals, Inc., Mary E. Wall
DATE OF
DOCUMENT
09-29-88
10-07-88
11-02-88
11-07-88
11-09-88
10-01-88
10-12-88
10-13-88
12-0~l-88
12-05-88
12-14-88
12-22-88
12-27-88
01-11-89
N/D
01-30-89
01-30-89
A-14
-------
Docket No, OAQPS 79-3, Part I
Subcategory XII-D
NUMBER
XII-D-248
XII-D-249
XII-D-250
XII-D-251
XII-D-252
XII-D-253
XII-D-254
XII-D-255
XII-D-256
XII-D-257
XII-D-258
XII-D-259
DATE REC'D
IN CDS '
01-30-89
01-30-89
01-30-89
01-30-89
01-30-89
01-30-89
02-01-89
02-01-89
02-13-89
03-06-89
04-28-89
04-28-89
COMMENTER etc.
CMA Chemical Manufacturing Company, Geraldine V.
Cox, et al.; Letter w/attachment (duplicate copy
also put into Dockets A-79-27; A-79-49; & A-80-14)
American Iron and Steel Institute, Neil Jay King
(Counsel of); Letter w/attachments (duplicate
copy also put into Docket A-79-16
UARG Utility Air Regulatory Group, F. William
Browne!! (Counsel of); Letter w/attachment
Massachusetts Institute of Technology,
Dale Hattis; Letter addressed to Lee Thomas
New York State Congress of Parents and
Teachers, Inc., Elsa Ford
API American Petroleum Institute, Terry F. Yosie-
Letter w/attachments (duplicate CODY of
Docket A-79-27, IX-D-11)
NRDC Natural Resources Defense Council
David D. Doniger
Exxon Company, U.S.A., H.T. Gibson; Letter w/
attachment (duplicate copy of Docket A-79-27
IX-D-12) '
Bethlehem Steel Corporation, David M. Anderson
(duplicate copy also put into Docket A-79-16)
API American Petroleum Institute, Terry F. Yosie-
Letter addressed to Don R. Clay (EPA)
TFT The Fertilizer Institute
API American Petroleum Institute, Terry F. Yosie-
1 A <^ ^ A u .../_O_^_^L~ ' ___»__ i J ._ __ . '
" r\ » T»f? f\T~
PATE OF
DOCUMENT
01-30-89
01-30-89
01-27-89
11-07-88
01-26-89
01-30-89
01-30-89'
01-30-89
01-30-89
01-19-89
11-22-88
02-21-89
XII-D-260
XII-D-261
04-28-89
04-28-89
Marvin Lewis (Philadelphia, PA); Letter N/D
addressed to Robert Ajax (EPA)
RFF Resources for the Future Center for Risk 03-22-89
Management, Paul R. Portney; Letter addressed
to William Reilly
A-15
-------
Docket No. OAQPS 79-3, Part I
Subcategory XII-D
Additional Comments Received After the Proposal
DATE REC'D
NUMBER IN DOCKET
XII-D-262 05-12-89
XII-D-263 05-12-89
XII-D-264 07-24-89
COMMENTER etc.
API American Petroleum Institute, Terry F. Yosie-
Letter w/attachment
API American Petroleum Institute, Paul Price;
Letter w/attachments
API, Terry F. Yosie;
Letter w/attachments
DATE OF
DOCUMENT
05-12-89
05-12-89
07-24-89
A-16
-------
BENZENE HEALTH EFFECTS
Docket No. OAQPS 79-3, Part I
Subcategory XII-F
Transcript/Statements of Hearings
Docket No.
Description
XII-F-1
XII-F-2
XII-F-3
XII-F-4
XII-F-5
Statement of Richard Kerch on behalf of
the American Mining Congress regarding
September 1, 19«8 Hearing before EPA
Statement of Lewis M. Cook on behalf of
the American Mining Congress regarding
September 1, 1988 Hearing before EPA
Statement of Dr. Douglas B. Chambers on behalf
of the American Mining Congress regardinq
September 1, 1988 Hearing before EPA
Presentation by Dr. Douglas B. Chambers on
behalf of the American Mining Congress
and The Fertilizer Institute before the
Sources and Transport Subconmittee of
the Radiation Advisory Cotmittee, Science
Advisory Board, of EPA; dated July 13, 1988
Presentation by Dr. Douglas B. Chambers on
behalf of the American Mining Congress
before the Dose and Risk Subconmittee,
Radiation Advisory Committee, Science
Advisory Board, of EPA; dated June 20, 1988
A-17
-------
Document No.
XII-F-6
XII-F-7
XII-F-8
XII-F-9
XII-F-10
XII-F-11
XII-F-12
XII-F-13
XII-F-14
XII-F-15
Benzene Health Effects
Docket No. OAQPS 79-3, Part I
Subcategory XII-F
Transcript of Hearing
Description
Statement of the American Petroleum Institute,
before the U.S. Environmental Protection
Agency, September 1, 1988.
Statement of David Doniger of the Natural
Resources Defense Council, before the U.S.
Environmental Protection Agency, September 1,
1988.
Statement of Stephen Rose on Behalf of the
Chemical Manufacturers Association, before the
U.S. Environmental Protection Agency,
September 1, 1988.
Testimony of the American Industrial Health
Council (AIHC), before the U.S. Environmental
Protection Agency, September 1, 1988.
Testimony of the American Coke and Coal
Chemicals Institute, before the U.S.
Environmental Protection Agency, September 1,
1988.
Testimony of the Idaho Mining Association,
before the U.S. Environmental Protection
Agency, September 1, 1988.
Statement of the Food and Water, Inc., before
the U.S. Environmental Protection Agency,
September 1, 1988.
Testimony of the Utility Air Regulatory Group,
before the U.S. Environmental Protection
Agency, September 1, 1988.
Testimony of the Nuclear Information and
Resource Service, before the U.S. Environmental
Protection Agency, September 1, 1988.
Comments by the Residents Against Chemical
Environment (R.A.C.E.), before the U.S.
Environmental Protection Agency, September 1,
1988.
A-18
-------
Document No.
XII-F-16
XII-F-17
Benzene Health Effects
Docket No. OAQPS 79-3, Part I
Subcategory XII-F
Transcript of Hearing
Description
List of Hearing Panel Members, Speakers, and
Attendees at the U.S. Environmental Protection
Agency Public Hearing on Benzene, September 1,
1988.
PUBLIC HEARING IN THE MATTER OF: Proposed
Regulations on National Emission Standards for
Hazardous Air Pollutants (Benzene), Transcript
?L"ear1n9' Washington, D.C., September 1,
19oo.
A-19
-------
COKE BY-PRODUCT RECOVERY PLANTS
Docket No. A-79-16
Subcategory VI-D
Additional Comments Received After the Proposal
NUMBER
DATE REC'D
IN CDS
VI-D-01 10-03-88
VI-D-02
VI-D-03
VI-D-05
VI-D-06
VI-D-07
VI-D-08
VI-D-09
VI-D-10
VI-D-11
10-03-88
10-03-88
VI-D-04 10-04-88
10-04-88
09-12-88
10-04-88
10-04-88
10-04-88
01-19-89
01-19-89
COMMENTER OR ADDRESSEE, TITLE DESCRIPTION, ETC.
American Coke and Coal Chemicals Institute,
Mark T. Engle (Same comment: OAQPS 79-3, Pt 1
XII-D-27 and A-79-27 IX-D-01)
Wilmer Cutler & Pickering, Neil Jay King (Counsel
for AMERICAN IRON AND STEEL INDUSTRY; Lettr w/
attachment (same comment OAQPS 79-3(1) XII-D-33)
API American Petroleum Institute, Terry F. Yosie;
Letter w/attachment (same material also put into
Dockets A-79-27; A-79-49; A-80-14 and OAQPS 79-3)
TFI The, Fertilizer Institute, Gary D. Myers;
Letter w/attachment (same material also put into
Dockets A-79-27; A-79-49; & A-80-14; OAQPS 79-3)
Bethlehem Steel Corporation, David M. Anderson
(duplicate of OAQPS 79-3 (I), XII-D-99)
Brandt Mannchen (Private Citizen) Houston, TX
(duplicate of OAQPS 79-3 (I), XII-D-04)
NRDC Natural Resources Defense Council, David D.
Doniger; Letter w/attachment (duplicate of
OAQPS 79-3 (I), XII-D-100)
Food and Water Inc., Judith H. Johnsrud; Letter
w/attachment (duplicate of OAQPS 79-3 (I),
XII-D-102)
Shenango Inc., James R. Zwikl
(Duplicate of OAQPS 79-3 (I), XII-D-109)
USS Technical Center, Richard Dworek; Letter
addressed to Robert L. Ajax (EPA)
USS Technical Center, Michale A. Hanson;
Letter addressed to Marsha S. Branscome (EPA)
DATE OF
N/D
10-03-88
10-03-88
10-03-88
09-30-88
09-03-88
10-03-88
09-27-88
09-30-88
10-27-88
10-31-88
A-20
-------
COKE BY-PRODUCT RECOVERY PLANTS
Docket No. A-79-16
Subcategory Vlr-D
NUMBER
DATE REC'
IN DOCKET
D
^COMMENTER
OR
ADDRESSEE,
TITLE
DESCRIPTION,
ETC.
DATE OF
DOCUMENT
VI-D-12 01-19-89
VI-D-13 01-30-89
VI-D-14
VI-D-15
VI-D-16
VI-D-17
VI-D-18
VI-D-19
VI-D-20
VI-D-21
VI-D-22
VI-D-23
VI-D-24
VI-D-25
01-30-89
02-13-89
04-14-89
04-14-89
04-14-89
04-14-89
04-14-89
04-14-89
04-14-89
04-14-89
04-14-89
04-15-89
USS United States Steel Corporation, Michael 04-22-87
A. Hanson; letter w/attachment addressed to
Brenda C. Shine (Midwest Research Institute)
[B. Bierman, Indiana Dept of Environmental Mgmt,
to G. Lacy, EPArSDA, received 11/8/88 (no cover
letter attached), Transmitting responses to
questionnaires from USS Corporation used by the
State of Indiana in the development of a control
strategy for coke oven by-product plant emissions.
American Iron and Steel Institute, Neil Jay King 01-30-89
(Counsel of); Letter w/attachments (duplicate
of Docket OAQPS 79-3(1), XII-D-249)
American Coke and coal Chemicals Institute, 01-30-89
Mark T. Engle
Bethlehem Steel Corporation, David M. Anderson 01-30-89
(duplicate of Docket OAQPS 79-3(1), XII-D-256
ABC Coke Company, James A. Cleghorn; Letter 12-05-88
addressed to Jack R. Farmer (EPA, RTP)
Sloss Industries Corp., Dan Bell; Letter addressed 12-05-88
to Jack R. Farmer (EPA, RTP)
. LTV Steel Company, Mary Lou Harmon; Letter 12-09-88
addressed to Jack R. Farmer (EPA, RTP)
National Steel Corp., Jack Heintz; Letter 12-16-88
addressed to Jack R. Farmer (EPA, RTP)
Bethlehem Steel Corp., William J. Riley;1 Letter 12-22-88
addressed to Jack R. Farmer (EPA, RTP)
Inland Steel Company, John D. Fekete; Letter 12-28-88
addressed to Jack R. Farmer (EPA, RTP)
Bethlehem Steel Corp., William J. Riley; Letter 12-29-88
addressed to Jack R. Farmer (EPA, RTP)
ARMCO Corporate Officers, B.A. Steiner; Letter 01-05-89
addressed to Jack R. Farmer (EPA, RTP)
Koppers Indutries, Spencer H. Tuggle; Letter 01-10-89
addressed to Jack R. Farmer (EPA, RTP)
USS Corp., Michael A. Hanson; Letter addressed 01-16-89
to Jack R. Farmer (EPA, RTP)
A-21
-------
FUGITIVE EMISSION SOURCES
Docket No. A-79-27
Subcategory IX-D
Additional Comments Received After the Proposal
DATE REC'D
NUMBER IN CDS
IX-D-01 10-03-88
IX-D-02 10-03-88
IX-D-03 10-03-88
IX-D-04
IX-D-05
IX-D-06
10-03-88
10-03-88
10-04-88
COMMENTER etc.
American Coke and Coal Chemicals Institute,
Mark T. Engle (Same comment: OAQPS 79-3, Pt 1
XII-D-27 and A-79-16 IV-D-52)
CMA Chemical Manufacturing Company, Geraldine V.
Cox, et al., Letter w/attachments (same materials
also put into Dockets A-79-49; A-80-14 and
OAQPS 79-3, Part I)
API American Petroleum Institute, Terry F. Yosie;
Letter w/attachment (same material also put into
Dockets A-79-16; A-79-49; A-80-14 and OAQPS 79-3)
Unocal Corporation, Michael Cardin
ILTA Independent Liquid Terminals Association,
Clement Mesavage, Jr. (duplicate item submitted
to Docket A-80-14)
DATE OF
DOCUMENT
N/D
10-03-88
10-03-88
09-30-88
09-30-88
TFI The Fertilizer Institute, Gary D. Myers; Letter 10-03-88
w/attachment (same material also put into
Dockets A-79-16; A-79-49; A-80-14; & OAQPS 79-3)
IX-D-07
IX-D-08
IX-D-09
10-06-88
10-31-88
10-31-88
IX-D-10 01-30-89
Kerotest Manufacturing Corp., Richard W. Conley 09-30-88
Letter w/attachment addressed to Eileen Claussen
(EPA) (duplicate of OAQPS 79-3, XII-D-198)
CMA Chemical Manufacturers Association, 07-12-88
Gerald V. Cox; Letter w/attachment addressed
to Janet S. Meyer (EPA, RTP) (duplicate item
submitted to Dockets A-79-49, A-80-14)
CMA Chemical Manufacturers Association, 07-12-88
Deborah D. Stine; Letter addressed to
Jennifer Buzun (Radian Corporation) (duplicate
item submitted to Dockets A-79-49, A-80-14)
CMA Chemical Manufacturing Company, Geraldine V. 01-30-89
Cox, et al.; Letter w/attachment (duplicate copy
also put into Dockets A-79-49; A-80-14; and
(OAQPS 79-3(1)
A-22
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FUGITIVE EMISSION SOURCES
Docket No. A-79-27
Subcategory IX-D
NUMBER
IX-D-11
IX-D-12
IX-D-13
IX-D-14
IX-D-15
IX-D-16
IX-D-17
IX-D-18
DATE REC'D
IH CDS
01-30-89
02-01-89
01-31-89
04-28-89
04-28-89
05-12-89
06-23-89
06-23-89
COMMENTER etc.
API American Petroleum Institute, Terry Y.
Letter w/attachments (duplicate copy of
Docket A-79-27, IX-D-11)
Exxon Company, U.S.A., H.T. Gibson; Letter
attachment (duplicate copy of OAQPS 79-3
XII-D-255)
Exxon Company, U.S.A., B.L. Taranto
Unocal Refining & Marketing Division,
John K. Bassett
Sterling Chemicals, Laura Inskeep; Letter
addressed to Jan Meyer (EPA)
API American Petroleum Institute, Terry F.
Letter w/attachment
API American Petroleum Institute, Terry F.
Letter addressed to Robert L. Ajax (EPA)
Marvin I. Lewis (private citizen V Phils. P;
Yosie;
w/
Ml,
Yosie;
Yosie;
t .
Letter addressed to Robert L. Ajax (EPA)
DATE OF
DOCUMENT
01-30-89
01-30-89
01-31-89
01-23-89
01-25-89
05-12-89
03-01-89
N/D
A-23
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ETHYLBENZENE/STRYRENE PLANTS
Docket No. A-79-49
Subcategory XII-D
Additional Comments Received After the Proposal
DATE REC'D
NUMBER IN CDS
XII-D-01 10-03-88
XII-D-02 10-03-88
XII-D-03 10-04-88
XII-D-04 10-31-88
XII-D-05 10-31-88
XII-D-06 01-30-89
10-03-88
10-03-88
COMMENTER etc.
CMA Chemical Manufacturing Company, Geraldine V.
Cox, et al., Letter w/attachments (same materials
also put into Dockets A-79-27; A-80-14 and
OAQPS 79-3, Part I)
API American Petroleum Institute, Terry F. Yosie;
Letter w/attachment (same material also put into
Dockets A-79-16; A-79-27; A-80-14 and OAQPS 79-3)
TFI The Fertilizer Institute, Gary D. Myers; Letter 10-03-88
w/attachment (same material also put into
Dockets A-79-16; A-79-27; A-80-14 & OAQPS 79-3)
CMA Chemical Manufacturers Association, 07-12-88
Gerald V. Cox; Letter w/attachment addressed
to Janet S. Meyer (EPA, RTP) (duplicate item
submitted to Dockets A-79-27, A-80-14)
CMA Chemical Manufacturers Association, 07-12-88
Deborah D. Stine; Letter addressed to
Jennifer Buzun (Radian Corporation) (duplicate
item submitted to Dockets A-79-27, A-80-14)
CMA Chemical Manufacturing Company, Geraldine V. 01-30-89
Cox, et al.; Letter w/attachment (duplicate copy
also put into Dockets A-79-27; A-80-14; and
(OAQPS 79-3(1)
A-24
-------
BENZENE STORAGE
XII-D-03
XII-D-04
Docket No. A-80-14
Subcategdry XII-D
Additional Comments Received After the Proposal
DATE REC'D
NUMBER
XII-D-01
XII-D-02 10-03-88
10-03-88
10-03-88
XII-D-05 10-04-88
XII-D-06 10-31-88
XII-D-07 10-31-88
COMMENTER etc.
DATE OF
DOCUMENT
CMA Chemical Manufacturing Company, Geraldlne V. 10-03-88
Cox, et al.. Letter w/attachments (same materials
aie« „..* ..*. n—,._- A-79-27; A-80-14
10-03-88
09-26-88
09-30-88
API American Petroleum Institute, Terry F. Yosle-
Letter w/attachment (same material also put Into
Dockets A-79-16; A-79-27; A-80-14 and OAQPS 79-3)
Saint Louis Department of Public Safety
Richard C. Knapp
ILIA Independent Liquid Terminals Association
toeDocketeA-7V9?27)Jr* {dupl1cate 1teiB submitted
TFLll!e Kertr?Zer Inst1tu1*, Gary D. Myers; Letter 10-03-88
w/attachment (same material also put Into
Dockets A-79-16; A-79-27; A-79-49; & OAQPS 79-3)
CMA Chemical Manufacturers Association, 07-12-88
Gerald V. COx; Letter w/attachment addressed
to Janet S. Meyer (EPA, RTP) (duplicate Hem
submitted to Dockets A-79-27, A-80-14)
CMA Chemical Manufacturers Association, 07^12-sa
Deborah D. Stlne; Letter addressed to
Jennifer Buzun (Radian Corporation) (duplicate
Hem submitted to Dockets A-79-27, A-80-14)
A-25
-------
-------
|1. ftVOMTNO.
EPA-450/3'89-31
T»TL«Awo«u«Tm.. Benzene Emissions from Ethyl benzene/styrene *• "•*»««• OATI
Process Vents, Benzene Storage Vessels, Equipment Leaks " """
and Coke By-Product. Recovery Plants - Background"Informaticft
and Responses to Technical Comments for 1989 Final Decisio
7. AUTHOR!*)
f
MMPOMMINQ ORGANIZATION NAMI AND AOOftUS
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, N.C". 27711
12. SJONSOBINO AGSNCV NAMI AND AOOACSS
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, N. C. 27711
IS. SUWLCMCNTAHV NOTES
ORGANIZATION nvonr NO
anH nFinal.decisions have been made on regulation of benzene emissions from existing
and new coke by-product recovery plants, benzene storage vessels, equipment leaks,
and ethylbenzene/styrene process vents. These decisions implement Section 112 of
M? cl^a-AU A$! fu are based ori the Administrator's determination of June 8, 1977
(42 FR 29332), that benzene presents a significant risk to human health as a result
or air emissions from one or more stationary source categories, and is therefore a
hazardous air pollutant. This document contains a summary of the comments on the
P™E*S?- of,these,standards in the Federal Register (53 FR 28496), the Environmental
Protection Agency s response to these comments, and a summary of the health, environmental
and economic impacts of the final standards. ivnumiientai
17.
MB
a.
oucmrrom
KiY *OBQ» AND OCCUM1NT ANALYSIS
Hazardous air pollutant
Benzene
Coke by-product recovery plants
Storage vessels
Ethylbenzene/styrene
Equipment leaks
f^m S30-J (ft**. 4.77) •••viou« CO.ITIOM >•
b.lO«NTl»l«B«/OMN INOIO TtHMS
Hazardous air pollutant
standards
NESHAP
19. S1CU
Unclassified
20. SMCUIIITY eukss
Unclassified
c. COSATI Rtid/Cra«p
13B
21. NO. OP PAQU
193
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