oEPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA-600 2-79-210d
December 1979
Research and Development
Status
Assessment of
Toxic Chemicals
Benzene
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5 Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-79-210d
December 1979
STATUS ASSESSMENT OF TOXIC CHEMICALS:
BENZENE
by
J. C. Ochsner
T. R. Blackwood
Monsanto Research Corporation
Dayton, Ohio 45407
and
L. D. Zeagler
Radian Corporation
Austin, Texas 78766
Contract No. 68-03-2550
Project Officer
David L. Becker
Industrial Pollution Control Division
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research Laboratory - Cincinnati, U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify
that the contents necessarily reflect the views and policies of
the U.S. Environmental Protection Agency, nor does mention of
trade names or commercial products constitute endorsement or
recommendation for use.
11
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FOREWORD
When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory - Cincinnati
(lERL-Ci) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently
and economically.
This report contains a status assessment of the air emis-
sions, water pollution, health effects, and environmental signi-
ficance of vinylidene chloride. This study was conducted to
provide a better understanding of the distribution and character-
istics of this pollutant. Further information on this subject
may be obtained from the Organic Chemicals and Products Branch,
Industrial Pollution Control Division.
Status assessment reports are used by lERL-Ci to communicate
the readily available information on selected substances to
government, industry, and persons having specific needs and
interests. These reports are based primarily on data from open
literature sources, including government reports. They are indi-
cative rather than exhaustive.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
111
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ABSTRACT
Benzene, one of the most significant commercial organic chemi-
cals in the United States, is a component of gasoline and a
major intermediate in the organic chemicals industry. Because
of its health hazards, it is also very important from an environ-
mental standpoint. Produced in quantity second only to ethylene,
the estimated 1977 capacity is 6.8 x 106 m3 divided among more
than 50 manufacturing plants. Increasing demand is expected
to continue, possibly by 7.5%/yr until at least 1980.
Benzene is primarily used in the synthesis of other organic
chemicals. Ethylbenzene, cumene, and cyclohexane production
account for more than 80% of benzene used in the United States.
Although production and process consumption is concentrated in
the Texas Gulf and Northeast areas, its presence in gasoline
gives it nationwide distribution. In fact, the largest total
mass of emission is a result of motor vehicle operations
(456 x 106 kg/yr). Major industrial sources of benzene emis-
sion include degreasing (73.1 x 106 kg/yr), ethylbenzene/styrene
(9.5 x 106 kg/yr), and cyclohexane manufacture (7.8 x 105 kg/yr).
Benzene clearly produces adverse health effects. It has long
been recognized as a poison if ingested in large quantities, and
at nonlethal concentrations, a variety of human central nervous
system disorders are observed. Federal standards for occupa-
tional exposure to benzene have been set, but further reduction
in allowable concentrations has been proposed. Regulatory action
under the Clean Air Act is awaiting results of an air monitoring
program. Water quality criteria are anticipated under the
Federal Water Pollution Control Act (FWPCA) by July 1978. The
Consumer Products Safety Commission is considering action con-
tingent on results of an Academy of Sciences study.
The following recommended areas for further study are: 1) ambient
levels of benzene and the population exposed, 2) environmental
reactivity, 3) benzene loss due to spills, accidents, or leaks,
4) benzene emissions from fugitive sources, 5) effects from non-
lethal doses of benzene, 6) benzene's connection with leukemia,
and 7) effect of modern motor vehicle emission controls on
benzene emissions.
xv
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This report was submitted in partial fulfillment of Contract
68-03-2550 by Monsanto Research Corporation under the sponsorship
of the U.S. Environmental Protection Agency. This report covers
the period November 1, 1977 to December 31, 1977. The work was
completed as of January 20, 1978.
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CONTENTS
Foreword iii
Abstract iv
Tables viii
Abbreviations ix
Conversion Factors and Metric Prefixes x
Acknowledgement xi
1. Introduction 1
2 . Summary 2
3. Source Description 5
Physical and chemical properties 5
Production 6
Process description 6
Uses 12
Transportation 13
4. Environmental Significance and Health Effects 18
Environmental significance 18
Health effects 18
5. Control Technologies 26
Emission source control methods 26
Control efficiencies 26
6. Regulatory Action 32
References 33
Glossary 36
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TABLES
Number
1 Benzene 3
2 Producing Companies, Plant Locations, and Capacity
of the Benzene Industry - 7
3 Estimated Benzene Production (1976) 11
4 Benzene Consumption (1976) 13
5 Benzene Emission Sources 19
6 Evaporative Emission Factors for Benzene Storage
Tanks Without Controls 21
7 Ambient Monitoring Data for Benzene 22
8 Toxicity Data for Benzene 25
9 Control Devices and Reported Control Efficiencies
for the Maleic Anhydride Industry 30
viii
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ABBREVIATIONS
FWPCA
LD50
MRC
NIOSH
OSHA
OTS
ppb
ppm
TC,
TD
'Lo
I
Lo
-Federal Water Pollution Control Act
-lowest reported concentration to have caused death
-calculated concentration expected to kill 50% of an
exposed population
-lowest reported dose to have caused death
-dose expected to kill 50% of a population
-Monsanto Research Corporation, Dayton, Ohio
-National Institute of Occupational Safety and Health
-Occupational Safety and Health Administration
-Office of Toxic Substances
-parts per billion
-parts per million
-lowest concentration reported to produce toxic effects
-lowest dose reported to produce toxic effects
IX
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CONVERSION FACTORS AND METRIC PREFIXES
To convert from
Degree Celsius (°C)
Gram/second (g/s)
Kilogram (kg)
Meter (m)
Meter3 (m3)
Meter3 (m3)
Meter3 (m3)
Metric ton
Metric ton
Pascal (Pa)
CONVERSION FACTORS
To
Degree Fahrenheit
Pound/hr
Pound-mass (avoirdupois)
Foot
Barrels
Foot3
Gallon (U.S. liquid)
Kilogram
Pound-mass
Pound-force/inch2 (psi)
Multiply by
= 1
1.
2.
8 t° +
32
7.937
2.205
3.281
6.293
3.531 x 101
2.642 x 102
000 x 103
205 x 103
1.450 x
Prefix
Kilo
Milli
Symbol
k
m
METRIC PREFIXES
Multiplication factor
103
10~3
Example
1 kPa = 1 x 103 pascals
1 mg = 1 x 10"3 gram
Standard for Metric Practice. ANSI/ASTM Designation:
E 380-76e, IEEE Std 268-1976, American Society for Testing and
Materials, Philadelphia, Pennsylvania, February 1976. 37 pp.
x
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ACKNOWLEDGEMENT
This report was assembled for EPA by Radian Corporation, Austin,
TX, and Monsanto Research Corporation, Dayton, OH. Mr. D. L.
Becker served as EPA Project Officer, and Dr. C. E. Frank, EPA
Consultant, was principal advisor and reviewer.
XI
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SECTION 1
INTRODUCTION
Benzene is one of the most significant commercial organic
chemicals in the United States. It is a component of gasoline
and a major intermediate in the organic chemicals industry-
Large quantities of benzene enter the environment and have
become the subject of increasing concern and widespread inves-
tigation. Benzene clearly produces adverse health effects.
Its commercial significance and pervasiveness mean that regula-
tory action must be considered. Devising a management strategy
will be a complex and difficult problem.
Much of the information needed to define regulatory action is
currently being generated by agencies outside the U.S. Office of
Toxic Substance (OTS). The purpose of this report is to summar-
ize available information on health effects, ambient concentra-
tions, and sources of benzene. Production methods and quantities
are described along with control techniques and regulatory action
under consideration.
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SECTION 2
SUMMARY
Benzene is a volatile, colorless, flammable liquid that is one
of the most important industrial organic chemicals produced in
the United States. Because of its potential health hazards,
it is also very important from an environmental standpoint.
However, a general lack of data prevents any accurate predic-
tion of its environmental reactivity.
Benzene is produced in over 50 locations in quantities second
only to ethylene. The estimated capacity for 1977 is 6.8 million
m3. Increasing demand is expected to continue, possibly by
7.5%/yr until at least 1980.
The two major sources of benzene are petroleum and coal, with
petroleum being the largest source. Six processes are used to
manufacture benzene; four operate on petroleum derivatives and
two operate on coal.
Benzene is primarily used in the synthesis of other organic chem-
icals. Ethylbenzene, cumene, and cyclohexane production account
for more than 80% of benzene used in the United States. Barring
any unexpected events, benzene will remain as one of the most
important chemicals to industry.
Benzene is shipped in drums and tank cars domestically by water
(79.6%), rail (14.8%), and truck (5.6%). Most pipeline shipment
is restricted to that which is captively used by the plant in
which it is produced.
There are several sources of benzene emissions. The largest
total mass of emission is from motor vehicles (exhaust fumes),
450 million kg/yr. Major industrial sources of benzene include
degreasing and ethyl benzene/styrene manufacture, 73.1 million
kg/yr and 9.5 million kg/yr, respectively. About 576,000 metric
tons of benzene are released to the atmosphere from the produc-
tion and use of benzene and products which contain it.
Information on levels of benzene in the atmosphere is sparse.
However, one study indicated high values for metropolitan areas
(Los Angeles and Toronto) which may be primarily due to exhausts
from motor vehicles. Benzene has been identified in the drinking
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water of three U.S. locations at levels of 2.0 ppb. It has also
been identified in subsurface water at levels of 10 ppm in brine
from one area, and 24 ppm in another geographic area having
extensive oil and gas deposits.
Benzene has long been recognized as a poison if ingested in
large quantities. The effects of nonlethal doses, including
long-term illnesses, are not fully understood. Many researchers
have concluded that more study is definitely needed, especially
to determine if benzene can cause cancer.
Control of benzene emissions can be achieved by preventing
release of the pollutant or by treating the waste streams.
Various techniques of implementing these ideas have been devel-
oped and are summarized in Table 1. Also presented are emissions
sources and rates, population exposed, and regulatory action.
TABLE 1. BENZENE
Emission source
Bnission rate,
10s kg/yr
Extent of problem
Population exposed
Control method
Regulatory agency or action
Production:
Catalytic reforming 2.6
Toluene dealkylation 1.4
Toluene disproportionation 0.04
Pyrolysis gasoline 0.6
Coke-oven light oil 0.2
Coke-oven operations 0.2
Production of benzene is gen- Incineration or vapor recovery OSHA has proposed a reduc-
erally localized in the
Texas Gulf and Northeast
systems. Wet scrubbing in
an absorber or a combination
of the above. (>95% effi-
ciency) . Hater treatment
generally involves primary
separation (70% to 90% effi-
ciency) followed by secondary
and possibly tertiary treat-
tion of the 10 ppm stand-
ard to 1 ppm 8-hr weighted
average with a ceiling of
5 ppm over a 15-min period.
Transport and storage:
Bulk terminal loading/storage
Industrial use:
Ethyl benzene/styrene 9.5
Cumene/phenol 2.4
Cyclohexane 7.B
Aniline 0.1
Chlorobenzenes 2.6
Haleic anhydride 2.0
Detergent alkylate 0.01
Surface coatings (paints) 3.2
Degreasing 73.1
Nitrobenzene 3.4
Fumaric acid 0.3
Acrylonitrile 0.2
Use of products containing benzenei
Automobile tank loading 5.9
Service station tanks 0.2
Motor vehicles 450
Oil spills 10
Modified loading procedures
(submerged or bottom loading)
in conjunction with vapor
recovery devices. Improved
storage tank designs.
Process consumption of benzene
is generally localized in
the Texas Gulf and North-
east areas.
The presence of benzene in
gasoline gives it nation-
wide distribution. Scarce
data indicate that most
Americans are probably
exposed continuously to
very low levels of benzene.
Incineration or vapor recovery
systems. Wet scrubbing in
an absorber or a combination
of the above. (>95% effi-
ciency.) Hater treatment
generally involves primary
separation (70% to 90% effi-
ciency) followed by secondary
and possibly tertiary treat-
ment.
OSHA has proposed a reduc-
tion of the 10 ppm stand-
ard to 1 ppm 8-hr weighted
average with a ceiling of
5 ppm over a 15-min period.
Vapor recovery and modified
loading procedures.
Catalytic converter.
Proper procedure after
benzene-containing spill.
EPA has initiated an air
monitoring program which
will determine benzene
levels in* selected areas.
Benzene has been designa-
ted a priority pollutant
under the Federal Hater
Pollution Control Act.
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Based upon the information in this report the following areas
for further study are recommended:
• More data is needed on ambient levels of benzene and
the population exposed.
• More information is needed on benzene's environmental
reactivity, for instance, its environmental residence
time.
• Information is lacking on the amount of benzene lost
due to spills, accidents, or leaks.
• The extent of benzene emissions from fugitive sources
is unknown.
• The effects from nonlethal doses of benzene are not
fully understood.
• More studies are needed to determine if there is a
connection between benzene and leukemia.
• The effect that modern emission controls will have on
benzene emissions from motor vehicles is an' area for
study.
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SECTION 3
SOURCE DESCRIPTION
PHYSICAL AND CHEMICAL PROPERTIES
Benzene is one of the most important industrial organic chemicals
produced in the United States. Because of its potential health
hazards, it is also very important from an environmental stand-
point. The behavior of benzene after it has been emitted to the
air or to a body of water is dependent to a large extent upon
its physical properties. These will control its stability,
chemical reactions, and long-term ambient concentrations in the
environment.
Benzene is a volatile, colorless, flammable liquid. Its chemical
formula is CgH6, and it has a structure represented as
H
C
HC
HC
CH
or
or
H
Its important chemical properties are listed below:
Molecular weight
Vapor pressure
Boiling point
Specific gravity
Octanol/water partition
coefficient
Physical state
Vapor specific gravity (air = 1)
Melting point
78.11
13 kPa at 25°C
80.1°C at 101 kPa
0.8787 at 20°C/4°C
2.28
Liquid
2.77
5.5°C
Solubility
Slightly (1.79 x 10 3 g/m3 H20)
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Little is known about benzene's environmental reactivity. In the
atmosphere, it slowly reacts with oxidizing materials. Benzene
is not photochemically reactive, but it is biodegradable (1).
It is quite persistant, and due to its high vapor pressure, it
is highly mobile in the atmosphere.
Benzene has been detected in both inland and marine waters.
Because of its biodegradability, some benzene is oxidized by
microorganisms in both air and water environments. A general
lack of data prevents any accurate prediction of the environ-
mental residence time of benzene (2).
PRODUCTION
Benzene is one of the most significant petrochemicals in the
United States. It is produced in quantity second only to
ethylene. In 1973, over 5.170 x 106 m3 of benzene were pro-
duced in the United States. The estimated capacity for 1977 is
6.805 x 106 m3 divided among more than 50 manufacturing plants.
A list of benzene manufacturers is presented in Table 2 (3).
The flexibility of most aromatics operations enables the re-
porting of only approximate capacities.
PROCESS DESCRIPTION
The two major sources of benzene are petroleum and coal, with
petroleum supplying the largest percentage. Six processes are
used to manufacture benzene; four of them operate on petroleum
derivatives and two operate on coal. These processes are listed
in Table 3 by estimated 1976 production and number of sites.
Petroleum-derived benzene is isolated from catalytic reformate
and pyrolysis gasoline and produced directly by the dealkylation
and disproportionation of toluene. Coal-derived benzene is iso-
lated from coke-oven light oil, a byproduct of coke manufacture.
Each of these processes is subsequently described.
(1) Dorigan, J. Scoring of Organic Air Pollutants: Chemistry
Production and Toxicity of Selected Synthetic Organic Chemi-
cals. Mitre Corporation, September 1976.
(2) Ocean Affairs Board, National Research Council1. Assessing
Potential Ocean Pollutants. Report No. 0-309-02325-4, U.S.
Environmental Protection Agency and National Science
Foundation, Washington, D. C., January 1975. 456 pp.
(3) Directory of Chemical Producers—U.S.A. Chemical Information
Services, Stanford Research Institute, Menlo Park,
California, 1977. 1059 pp.
6
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TABLE 2. PRODUCING COMPANIES, PLANT LOCATIONS, AND CAPACITY OF THE BENZENE INDUSTRY (3)
Company
Location
Annual capacity,
103 m3
Raw material
Amerada Hess Corp.
Hess Oil Virgin Islands Corp.,
subsidiary
American Petrofina, Inc.
American Petrofina Co. of Texas,
subsidiary
Cosden Oil & Chemical Co.,
subsidiary
Armco Steel Corp.
Ashland Oil, Inc.
Ashland Chemical Co., division
Petrochemicals division
Atlantic Richfield Co.
ARCO Chemical Co., division
Bethlehem Steel Corp.
CF&I Steel Corp.
The Charter Co.
Charter Oil Co., subsidiary
Charter International Oil
Co., subsidiary
Cities Service Co.
Chemicals Group
Columbian Chemicals division
Coastal States Gas Corp.
Coastal States Marketing, Inc.,
subsidiary
St. Croix, VI
Port Arthur, TX
Big Spring, TX
Middletown, OH
Ashland, KY
North Tonawanda, NY
Carson, CA
Channelview, TX
Houston, TX
Bethlehem, PA
Sparrows Point, MD
Pueblo, CO
Houston, TX
Lake Charles, LA
Corpus Christi, TX
95
57
170
11
238
57
45
132
159
19
57
11
19
95
265
Petroleum
Petroleum, captive
Petroleum, partly captive
Coal
Petroleum, partly captive
Petroleum
Petroleum
Petroleum
Petroleum
Coal
Coal
Coal
Petroleum
Petroleum
Petroleum, partly captive
(continued)
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TABLE 2 (continued)
Company
Location
Annual capacity,
103 m3
Raw material
oo
Commonwealth Oil Refining Co., Inc.
Commonwealth Petrochemicals,
Inc., subsidiary
Crown Central Petroleum Corp.
Chemicals division
Dow Chemicals U.S.A.
Exxon Corp.
Exxon Chemicals Co., division
Exxon Chemicals Co. U.S.A.
Getty Oil Co.
Getty Refining and Marketing
Co. subsidiary
Gulf Oil Corp.
Gulf Oil Chemicals Co., division
Petrochemicals, division
Independent Refining Corp.
Interlake, Inc.
Jones and Laughlin Industries, Inc.
Jones & Laughlin Steel Corp.,
subsidiary
Kerr-McGee Corp.
Southwestern Refining Co., Inc.
subsidiary
Ponce, PR
Pasadena, TX
Bay City, MI
Freeport, TX
Baton Rouge, LA
Baytown, TX
El Dorado, KS
Alliance, PA
Philadelphia, PA
Port Arthur, TX
Winnie, TX
Toledo, OH
Aliquippa, PA
Corpus Christi, TX
700
87
114
189
83
227
49
265
125
144
11
4
38
61
Petroleum
Petroleum
Petroleum, captive
Petroleum, captive
Petroleum
Petroleum, partly captive
Petroleum, captive
Petroleum
Petroleum, captive
Petroleum, captive
Petroleum
Coal
Coal
Petroleum
(continued)
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TABLE 2 (continued)
Company
Location
Annual capacity,
103 m3
Paw material
Marathon Oil Co.
Mobil Corp.
Mobil Oil Corp.
Mobil Chemicals Co., division
Petrochemicals division
Monsanto Co.
Monsanto Chemicals Intermediates
Co.
Northwest Industries, Inc.
Lone Star Steel Co., subsidiary
Pennzoil Co.
Atlas Processing Co., subsidiary
Phillips Petroleum Co.
Phillips Chemicals Co.
Phillips Puerto Rico Core, Inc.,
subsidiary
Quintana-Howel1
Shell Chemicals Co.
Standard Oil Co. of California
Chevron Chemical Co., subsidiary
Petrochemicals division
Industries Chemicals
Standard Oil Co. (Indiana)
Amoco Oil Co., subsidiary
The Standard Oil Co. (Ohio)
BP Oil Inc., subsidiary
Texas City, TX
Beaumont, TX
Chocolate Bayou, TX
Lone Star, TX
Shreveport, LA
Sweeney, TX
Guayama, PR
Corpus Christi, TX
Deer Park, TX
Odessa Park, TX
Wood River, IL
El Segundo, CA
Texas City, TX
Marcus Hook, PA
23
38
284
57
84
416
27
379
45
170
87
322
30
Petroleum, captive
Petroleum
Petroleum, captive
Coal
Petroleum
Petroleum, captive
Petroleum, partly captive
Petroleum
Petroleum
Petroleum
Petroleum
Petroleum, captive
Petroleum, captive
Petroleum
(continued)
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TABLE 2 (continued)
Company
Location
Annual capacity,
103 m$
Raw material
Sun Oil Co., Inc.
Sun Oil Co. of Pennsylvania,
subsidiary
Suntide Refining Co., subsidiary
Tenneco Inc.,
Tenneco Oil Co., division
Texaco, Inc.
Union Carbide Corp.
Chemicals and Plastics division
Union Oil Co. of California
Union Pacific Corp.
Champlin Petroleum Co.,
subsidiary
United States Steel Corp.
USS Chemicals division
TOTAL
Marcus Hook, PA
Toledo, OH
Tulsa, OK
Corpus Christi, TX
Chalmette, LA
Port Arthur, TX
Westville, NJ
Taft, LA
a
Beaumont, TX
Lemont, IL
Corpus Christi, TX
Clairton, PA
Geneva, UT
57
132
91
132
38
170
132
189
84
64
38
170
15
6,805
Petroleum
Petroleum
Petroleum
Petroleum, captive
Petroleum
Petroleum, partly captive
Petroleum, partly captive
Petroleum, captive
Petroleum
Petroleum
Petroleum, captive
Coal
Coal
Joint venture with American Petrofina of Texas, subsidiary of American Petrofina Incorporated.
NOTE: Some petroleum operators also isolate benzene from purchased coal-derived light oil.
Sources: Compiled in association with the World Hydrocarbons Program and communication with industry.
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TABLE 3. ESTIMATED BENZENE PRODUCTION (1976)
Capacity, Number of
Process 10 6 m3 sites
Catalytic reforming 2.8 39
Toluene dealkylation 1.5 16
Toluene disproportionation 0.04 2
Pyrolysis gasoline 0.68 10
Purchased coke-oven light oil 0.21 5
Coke-oven operations 0.25 6
TOTAL 5.28
More than one process per site may be performed.
Catalytic Reforming
Catalytic reforming converts the paraffins and naphthalenes in
naphtha to a higher octane reformate; the reformate contains a
high percentage of aromatics. Reactions include cyclization of
paraffins and dehydration and dealkylation of naphthalenes.
Reformers are dedicated to production of either gasoline-blending
components or petrochemical feedstocks. Feed to the latter
produces a reformate containing 40% to 60% aromatics. The
aromatic fraction is separated from the reformate via solvent
extraction. The aromatic-rich extract can then be further
separated into benzene, toluene, and xylenes by distillation.
Benzene purities of 99.9% can be obtained (4).
Olefin Production—Pyrolysis Gasoline
Ethylene and propylene (and other olefins) are produced by
cracking lower paraffins (propane or butane) or heavier stocks
(naphtha or gas oils). A byproduct is pyrolysis gasoline, which
can contain up to 80% aromatics (4). Purification of the gaso-
line requires hydrogenation for olefin saturation followed by
solvent extraction. Processing details can be found in the
literature (4-6).
(4) Parsons, T. B., et al. Industrial Process Profiles for
Industrial Use: Basic Petrochemicals Industry, Chapter 5.
Contract 68-02-1319, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, January 1977.
(5) Refining Handbook. Hydrocarbon Processing, 53(9):192,
1974.
(6) Petroleum Processing Handbook, Chapter 3. W. F. Bland and
R. L. Davidson, eds. McGraw-Hill Book Co., New York, New
York, 1967. pp. 1-152.
11
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Toluene Dealkylation/Disproportionation
Toluene is used as the feedstock for two different benzene-
producing reactions. In the presence of hydrogen, it can be
dealkylated to yield benzene and methane. Higher alkyl aromatics
are sometimes dealkylated to yield naphthalenes, with appreciable
quantities of benzene formed as a byproduct. If 2 mol of toluene
are catalytically reacted, 1 mol of benzene and 1 mol of xylene
are produced (disproportionation). Products of all reactions
must undergo distillation for separation. The toluene feed to
these reactions generally comes from solvent extraction of
catalytic reformate and can contain mixed xylenes as well as
toluene (4).
Coke-Oven Light Oil
Coke manufacturing, which involves high-temperature coal carbon-
ization, produces a light byproduct containing benzene. Further
processing of the light oil sometimes includes hydrogenation for
sulfur removal. Standard separations techniques are employed for
benzene purification. There is a large potential for producing
benzene from coal liquefaction processes, but these are several
years from commercialization.
USES
The primary end use for benzene is in the synthesis of other
organic chemicals. Ethylbenzene, cumene, and cyclohexane pro-
duction account for more than 80% of the benzene used in the
United States. A detailed breakdown is presented in Table 4 (7)
and detailed discussions of these uses of benzene are found in
Reference 8. A chemical tree is presented in Figure 1 (7).
Historically, demand has increased significantly because of the
market for styrene monomer, phenol, cyclohexane, nitrobenzene,
and maleic anhydride. Increasing demand is expected to continue,
possibly by 7.5%/yr until at least 1980 (9). Barring some
(7) Chemical Origins and Markets, Fifth Edition, G. M. Lawler,
ed. Chemical Information Services, Stanford Research
Institute, Menlo Park, California, 1977- 118
(8) Wilkins, G. E. End Use Patterns for Significant Organic
Chemicals. Contract 68-02-1319, U.S. Environmental Pro-
tection Agency, Research Triangle Park, North Carolina,
July 1976.
(9) Ponder, T. C. Benzene: Outlook Through 1980. Hydrocarbon
Processing, 55 (11) :217-218, 1976.
12
-------
TABLE 4. BENZENE CONSUMPTION (1976) (7)
Product use
Ethylbenzene
Cumene
Cyclohexane
Aniline
Chlorobenzenes
Maleic anhydride
Detergent alkylate
Miscellaneous applications
Exports
Percent
50.0
16.6
14.9
4.3
3.5
2.7
2.6
3.0
2.4
catastrophe or emergence of a less expensive raw material, ben-
zene will remain as one of the most important chemicals to
industry.
TRANSPORTATION
Drums and tank cars are standard containers for benzene. Accord-
ing to one study (10), 79.6% of domestically shipped benzene
goes by water, 14.8% by rail, and 5.6% by truck. Most pipeline
shipment is restricted to benzene that is used captively by the
plant in which it is produced.
(10) Dawson, G. W., A. J. Shuckrow, and W. H. Swift. Control
of Spillage of Hazardous Polluting Substances. Contract
14-12-866 (PB 197 596), U.S. Department of the Interior,
Federal Water Quality Administration, Washington, D.C.,
November 1970. 96 pp.
13
-------
1
3
5
A
1
B
ETHYLBENZENE ^_
BENZENESULFONIC ACID —
_ _ _
DODECYLBENZENE
r
C
"PHENOL ISEE cei
HESORCINOL (SEE C9I
UNSATURATED POLYESTER
RESINS
FUMARIC ACID ISEE BIOI
LUBE OIL ADDITIVES
TETRAHYOROPHTHALIC
ANHYDRIDE
ALKYD RESINS
MALEIC HYDRAZIOE~1 ,
MALATHION _J
LUBE OIL ADDITIVES
SURFACE ACTIVE AGENTS
0-.P-NITROCHLOROBENZENE ISEE F3I
DDT
HEAT TRANSFER MEDIUM
TANNING AGENT
PHENOL ISEE C6)
™
4
D
FLOOR POLISHES
TEXTILE SIZING
SURFACE-ACTIVE AGENTS
AOHESIVES
UAItl CPRAVC
PHARMACEUTICALS
ALKYD RESINS
"COSMETICS
PHARMACEUTICALS
FOOD PRODUCTS
DODECYLBENZENE SULFONATES """]
DODECYLBENZYL CHLORIDE |
FUNGICIDE
INSECTICIDE
HEAT TRANSFER MEDIUM
OF ISOCYANATES AND
METAL CLEANING)
BISPHENOL A (SEE F9)
CYCLOHEXANONE ISEE F1)
E
"PLANT GROWTH REGULATORS
PESTICIDES
UNSATURATED POLYESTER
EPOXY HARDENERS
»- SURFACE-ACTIVE AGENTS
DYE INTERMEDIATE
"AGRICULTURAL CHEMICALS
DYES
"MOTH REPELLANT
INSECTICIDE
DYES
DEODORANT
"MOLDING COMPOUNDS
LAMINATES
FRICTION MATERIALS
FOUNDRY BINDERS
PLYWOOD, PARTICLEBOARD. AND
RUBBER PROCESSING
PAPER TREATING
"pOLYPHENYLENE OXIDE
POLYMERS
ANTIOXIDANTS
"— H
+\
^L
Figure 1. Benzene product flow diagram (7).
Reproduced by permission of SRI International, Menlo Park, CA.
-------
7
R
9
10
>
A
CUMENE— ^-CUMENE HYOROPEROXIDE •*•
BENZENE HEXACHLOFIIDE
SODIUM m BENZENE OISULFONATE >
B
k
—
ACtTONt
AVIATION FUEL
SOLVENT
CUMENE SULFONIC ACID.
MOTOR FUELS
•POLYCHLOROBENZENE »
PAPER SIZING RESINS
UNSATURATED POLYESTER RESINS
ALKYD RESINS
FOOD ACIDULANT
PLASTICIZERS
C
ALKYLPHENOLS (OTHER THAN
NONYLPHENOL AND
CYCLOHEXANOL (SEE Fl)
2.4-DICHLOROPHENOXYACETIC ACID **
12.4-DI
"HEAT TRANSFER MEDIUM
PERFUMES
"T2,4>TETRACHLOROBENZENE »
DYES
PHENOL RESOflCINOL
ULTRAVIOLET ABSORBERS (e.g..
2HYDROXY-40CTOXY
BENZOPHENONE)
nvp«
PHARMACEUTICALS (e.g ,
HEXYLRESORCINOL. MERBROMIN)
TANNING AGENTS
LEAD STYPHNATE (FOR
EXPLOSIVES DETONATION*
POLYCHLORINATED BIPHENYLS— •• fr-
HEAT TRANSI-ER MEDIUM
FUNGICIDES
DYEING ASSISTANT FOR POLYESTER
D
PHENOLIC RESINS {SEE 05)
RUBBER TACKIFIERS AND
PHOSPHATE ESTERS » 1 FUNCTIONAL
| FLUIDS
SURFACE-ACTIVE AGENTS
PHENOLIC RESINS (SEE OSI
"DYES
PHARMACEUTICALS
_IM,NESSALTS ^] ^HE«»"='«s
AUTOMOBILE INTERIORS
SMALL APPLIANCE COMPONENTS
[TM.NE'SALTS^]"^ HERBICIDES
1
r- T
1 2.4.6-THICHLOROPHENOXV.
L_ ACETIC ACID I2.4>TI
2.4.6.TRICHLOROPHENOL —1
TRANSFORMER FLUIDS
PENTACHLOROPHENOL (SEE G6)
•HYDROGEN PEROXIDE
DIELECTRIC FLUID IN
1RANSF ORDERS AND CAPACITORS
E
Figure 1 (continued)
-------
h*
H*
), ^.
F
POLYETHYLENE MANUFACTURE)
MINT AND VARNISH REMOVER
Sfti VP^T
1
G
CYCLOHEXVL ESTERS !<•».
STABILIZER AND DYE SOLVENT
IN Tf XTILE INDUSTRY
AOIPIC ACID (SEE ABOVEI
CYCLOHEXANONE OXIME™^
I-CAPROLACTONE _J
SOLVENT (e.g.. FOR LACQUERS.
ELASTOMERS. LEATHER DECREASING]
"ORGANIC SYNTHESIS
RUBBER COMPOUNDING AGENT
3,3-DICHLOROBENZIOINE
O-CHLOROANILINE
o-ANISIDINE
n-NITROANILINE t Dy|;-
S.4.0INITHOCHLOR08ENZENE
0 DICHLOHOBENZENE
OIANISIDINE
BRANCHED DOOECYLPHENOL >
SOLVENT REFINING
1
H
DYES
RUBBER CHEMICALS f».g.. THIAZOLE)
PHOTOGRAPHIC CHEMICALS
(e.g., HYOROQUINONE)
^s^^
p-NITROANILINE-
o-SULFONIC ACID —
~~— — *
SURFACE-ACTIVE AGENTS
SURFACE-ACTIVE AGENTS
ANTIOXIOANTS
SALICYLIC ACID —
ANISOLi ~^^^
^^-
1
~YLON ee
ADIPONITRILE
ADIPATE PLASTICIZERS
FOOD ACIDULANT
-RIGID POLYURETHANE FOAM
1
DYES
"ACETYLSAHCYCLIC ACID (ASPIRIN)
PRESERVATIVES
MEDICINALS
RUBBER PROCESSING CHEMICALS
~SECTICID£S
PERFUMES
SOLVENT
J
"PHOTOGRAPHIC CHEMICALS
ANTIOXIDANTS
MEDICINALS
POLYUPiETHANES
PHARMACEUTICALS
ANTIOXIDANT
DYES
[PHOTOGRAPHIC CHEMICAL
"PHENACETIN— *• MEDICINALS (ANALGESIC)
DYES
DYES
PHOTOGRAPHIC DEVELOPING AGENT
RUBBER ACCELERATORS AND
ANTIOXIOANTS
-
1
2
3
4
5
Figure 1 (continued)
-------
•
—
SOLVENT It*. FOR PROTECTIVE
COATINGS, CELLULOSE
ACETATE SPINNING. CHEMICAL
ADHESIVESI
PHARMACEUTICALS
METHYL BUTYNOL
F
t
oCRESOL
PHENOLPHTHALEIN 1 ,
PHENYLSAL ICY LATE I
DYES
METHACRYLIC ACID ^
HEXYLENE GLYCOL y
" ~
CORROSION RESISTANT POLYESTERS V
ACETIC ANHYDRIDE
ACETYL CHLORIDE
G
WOOD PRESERVATIVES
FUNGICIDES
"PLASTICIZEHS (e.g.. TRIPHENYL PHOSPHATE)
HYDRAULIC FLUIDS
~YES
EXPLOSIVES
METHACRYLATE ESTERS (e.g..
n-BUTYL. ETHYL. 2-ETHYL-
HEXYL. AND ISOBUTYL
CARBOXYLATEO POLYMERS
EMULSION POLYMERS FOR ADHESIVES
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METHYL ISOBUTYL KETONE IMIBKI >•
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ESTERS AND ETHERS. RESINS. GUMS)
"HYDRAULIC BRAKE FLUIDS
PRINTING INKS
FUEL ADDITIVE
\
POWER TOOL HOUSINGS
PARTS FOR ELECTRONICS
AND APPLIANCES
PIGMENTS
PESTICIDES
FOOD PRESERVATIVES
PHARMACEUTICALS
H
SURFACE COATING RESINS
MOLDING AND EXTRUSION POWDERS
EMULSION POLYMERS (e.g.. FOR
ADHESIVES. PAPER COATINGS.
POLISHES)
UNSATURATED POLYESTER RESIN
MODIFIER
n-BUTYL. ETHYL, 2-ETHYL-
HEXYL. ISOBUTYLI ISEE HBI
ACRYLIC FIBERS
ACRYLIC FILM
y
SOLVENT (e.g.. FOR SURFACE
COATINGS, INSECTICIDES,
ADHESIVES, PHARMACEUTICAL
MANUFACTURE)
RARE METAL EXTRACTION
ALCOHOL OENATURANT
/
ACRYLATE ESTERS leg. ETHYL.
BUTYL. 2ETHYLHEXYL.
AC11YLATESI
1
ADVERTISING SIGNS AND DISPLAYS
GLAZING
LIGHTING FIXTURES
BUILDING PANELS
SURFACE COATING RESINS
ACRYLIC LACQUERS
ACRYLIC EMULSION POLYMERS
TROTHER IN MINERAL AND
COAL BENEFICIATION
SOLVENT FOR LACQUERS
TROTECTIVE COATINGS
REINFORCED PLASTICS (eg.. FOR
ELECTRONIC CIRCUIT BOARDS. PIPES)
ADHESIVES
FLOORING AND PAVING
pLA^ltyQ
APPLIANCE COMPONENTS
OUTDOOR LIGHTING AND SIGNS
AUTOMOTIVE LIGHTING (eg..
TELEPHONE EQUIPMENT
POWER TOOLS
OFFICE AND BUSINESS MACHINES
ELECTRONICS COMPONENTS
J
6
0
9
10
Figure 1 (continued)
-------
SECTION 4
ENVIRONMENTAL SIGNIFICANCE AND HEALTH EFFECTS
ENVIRONMENTAL SIGNIFICANCE
Benzene is one of the major petrochemical intermediates produced
and used in the United States. It has also been identified as a
potential hazard. This section will examine sources of benzene
emissions, ambient levels of benzene that result, secondary
emissions formed, and the population at risk.
Sources of Emissions
There are several sources of benzene emissions. The largest
emission source of benzene is motor vehicles (exhaust fumes).
The largest individual sources of benzene are estimated to be
from cyclohexanes, nitrobenzene and chlorobenzenes manufacture.
Table 5 shows that in 1976, an estimated 576 x 106 kg of benzene
were emitted to the atmosphere from 132 x 106 stationary and
mobile sources. This includes an estimated 110 million kg/yr
from production, transportation, storage, and use of benzene,
456 million kg/yr from refueling and operation of motor vehicles,
and 10 million kg/yr from oil spills (private communication,
T. W. Hughes, Monsanto Research Corporation; Reference 11; and
engineering estimates as described in this section).
Production and Subsequent Processing Into Other Products—
The processes employed for benzene production are catalytic
reforming/aromatics extraction, olefin manufacture/pyrolysis gas
processing, toluene hydrodealkylation and disproportionation,
and coking of coal. Hydrocarbons can be emitted from each of
these processes in the form of fugitive leaks; e.g. from valves
or flanges. Although emission factors exist for fugitive hydro-
carbon emissions from oil refineries (12), no data specifically
(11) Eimutis, E. C., and R. P. Quill. Source Assessment:
Noncriteria Pollutant Emissions. EPA-600/2-77-107e, U.S
Environmental Protection Agency, Research Triangle Park,
North Carolina, July 1977. 113 pp.
(12) Compilation of Air Pollutant Emission Factors, Second
Edition (with Supplements 1-7). Publication No. AP-42,
U.S. Environmental Protection Agency.- Research Triangle
Park, North Carolina, 1973.
18
-------
TABLE 5. BENZENE EMISSION SOURCES
Emission source
Benzene production:
Catalytic reforming
Toluene dealkylation
Toluene disproportionation
Pyrolysis gasoline
Coke-oven light oil
Coke-oven operations
Benzene consumption:
Ethylbenzene/styrene
Cumene/phenol
Cyclohexane
Aniline
Chlorobenzenes
Maleic anhydride
Detergent alkylate
Surface coatings (paints)
Degreasing
Nitrobenzene
Fumaric acid
Acrylonitrile
Other sources:
Automobile tank loading
Service station tanks
Bulk terminal loading/storage
Motor vehicles
Oil spills
TOTALS
1976 Estimated
benzene emis-
sion rate,
106 kg/yr (11)
2.63
1.4a
0.04a
0.6a
0.2a
0.2a
9.5a
2.4a
7.8a
o.ia
2.6
2.0a
0.01
3.2a
73.1
3.4
0.3a
0.2a
5.9
0.2
0.04
450b
10b
576
Number of
sources
39
16
2
10
5
6
12
9
8
7
7
9
5
8,745
1,300,000
9
6
6
226,500
226,500
30,900
130,000,000
787
131,800,000
Mass
emissions
per source,
kg/yr
67,000
88,000
20,000
60,000
40,000
33,000
190,000
270,000
975,000
14,000
370,000
220,000
2,700
370
56
380,000
50,000
33,000
26
80
1
3
12,000
Private communication, T. W. Hughes, Monsanto Research Corporation, Dayton,
Ohio.
See text, 1971 emissions estimates.
19
-------
address benzene. Processes that use catalysts undergo periodic
catalyst regeneration to burn off hydrocarbons adhering to the
catalyst surface. Existing data on emissions from these sources
encompass only hydrocarbons in general. There are potential
aqueous emissions from olefins/pyrolysis gasoline manufacture,
pyrolysis gas hydrotreating, coal coking, and aromatics extrac-
tion. A sludge is produced in the extraction processes as well.,
All of these streams have the potential of containing benzene.
Benzene is a feedstock for several organic chemical production
processes .as well as a gasoline blending component. Fugitive
hydrocarbon (includes benzene) emission potential is as common
as the lack of emission data. Almost all of the processes are
catalytic, and benzene could be released during solid catalyst
regeneration. [Process units maintained at atmospheric pressure
by open vents can be sources of benzene emissions. [In nitro-
benzene manufacture, 8.2 kg benzene/metric tona nitrobenzene can
be emitted from absorber vents (13).] Scrubber air from the
recovery section in maleic anhydride production can contain as
much as 107 kg benzene/metric ton of product (13) .
Benzene is released to aqueous streams in different ways, depend-
ing on the process. The liquid-phase ethylbenzene process dis-
charges a scrubber effluent water containing 11 kg of benzene/
metric ton water (13). The vapor process has spent caustic and
wash streams that contain significant amounts of benzene. Cumene
recovery produces a wastewater stream contaminated with benzene.
Solvent extraction is employed in cyclohexane production, and
this produces a benzene-contaminated wash water. Water washing
of the nitrobenzene product stream produces an aqueous waste
containing benzene. Scrubbing and stripping operations in the
bromobenzene and biphenyl processes also generate aqueous benzene
mixtures.
Storage—
Benzene, a fluid of intermediate volatility, is stored in float-
ing roof tanks (internal or external) or fixed-roof tanks having
vapor recovery systems. Emissions from these tanks result from
poor floating roof seals, evaporation from wetted walls during
emptying of floating roof tanks, venting of vapor recovery units,
and exceeding the vapor space capacity in variable vapor space
tanks (internal roof). Methods for calculating losses are well
1 metric ton equals 106 grams; conversion factors and metric
system prefixes are presented in the prefatory material.
(13) Industrial Process Profiles for Environmental Use: Chapter
6, The Organic Chemicals Industry, Part I (Draft). Contract
68-02-1320, Task 17, and Contract 68-02-1325, Task 70, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
20
-------
documented (14). Storage losses account for significant frac-
tions of all hydrocarbon emissions. Table 6 presents evaporative
emission factors for benzene storage tanks without controls (12).
TABLE 6. EVAPORATIVE EMISSION FACTORS FOR BENZENE
STORAGE TANKS WITHOUT CONTROLS (12)
Fixed roof tanks
Breathing loss,
kg/day-m3
New tank Old tank Throughput
conditions conditions loss, kg/m3
Floating roof tanks
Standing storage
loss, kg/day-m3
New tank Old tank
conditions conditions
Variable vapor
space tanks
Throughput
loss , kg/m3
0.0094 0.011 0.27 0.0013 0.0031 0.25
Transportation—
Benzene is transported in railroad tank cars or carried on ships
or trucks in 0.21-m3 drums. Emissions can result from spills,
leaks, loading, and accidents. Detailed studies of hydrocarbon
losses have been performed, but little information on benzene
losses exists (15, 16). In a study of hazardous material spill-
age into water streams, benzene was ranked as sixth among chemi-
cals likely to cause significant water pollution due to spillage
during transport (10).
Motor Vehicles—
Motor vehicles are sources of benzene emissions during both fuel-
ing and operation. Gasoline evaporation from vehicle refueling
results in 1.4 kg of hydrocarbons/m3 pumped (12). Loading and
unloading of trucks and underground tanks at service stations
have been estimated to transfer about 1.5 kg/m3. The large quan-
tities of gasoline consumed annually result in an emission of
24 million kg/yr of benzene (17); however, this estimate is based
on an assumption that 1% benzene exists in the vapor. The vapor
contains only 0.01% (11). Emissions of unburned hydrocarbons
from engine exhausts also present a hazard. Approximately
(14) Burklin, C. E., and R. L. Honerkamp. Revision of Evapora-
tive Hydrocarbon Emission Factors. Radian Project
100-086-01, Radian Corporation, Austin, Texas, June 1976.
(15) Air Pollution Engineering Manual, Second Edition. J. A.
Danielson, ed. Publication No. AP-40, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
May 1973. 987 pp.
(16) Burklin, C. E., E. C. Cavanaugh, J. C. Dickerman, S. R.
Fernandes, and G. C. Wilkins. Control of Hydrocarbon
Emissions from Petroleum Liquids. EPA-600/2-75-042, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 1975. 245 pp.
(17) Benzene from Gasoline Evaporation is "Significant Health
Hazard," EDF says. Environmental Report 1977, 1363.
21
-------
450 million kg of benzene were released in hydrocarbon emissions
from motor vehicles in 1971.
Oil Spills—
The OTS has reported a possible release of from 10 to 11 million
kg/yr of benzene due to oil spills; however, no data have yet
been found to support this figure The maximum content of
benzene in crude oil is approximately 3.0% (18). If all crude
oil contained 3% benzene and if it all evaporated when the oil
spilled, approximately 0.3 billion kg/yr of oil would have to be
lost to produce 10 million kg of benzene. Since one source
reports annual oil spillage to be about 1.8 billion kg/yr (2),
the OTS estimate is reasonable.
Environmental Levels
Information on levels of benzene in the atmosphere is deficient.
Table 7 summarizes ambient monitoring data for benzene in selec-
ted areas of the United States and shows that the observed am-
bient levels of benzene are 1 ppb to 100 ppb (volume basis).
The high values for metropolitan areas (Los Angeles and Toronto)
may be primarily due to exhausts from motor vehicles (19).
TABLE 7. AMBIENT MONITORING DATA FOR BENZENE (19)
Concentrations
Geographical location
Vancouver, Canada
Near solvent reclamation plants
Los Angeles Basin
Downtown Los Angeles
Los Angeles Basin
Zurich, Switzerland
Riverside, California
Toronto, Canada
Sampling/analysis technique
Cold trap/GC-FIDa h
Grap sample/GC-MS, IR°
Cold trap/GC-FID
Grab sample/GC-FID
Cold trap/GC-FID
Charcoal trap/GC-MS,GC-F!D
Cold trap/GC-FID
Cold trap/GC-FID
Lowest
1
5
15
7
Average
15
13
, PPb
Highest
10
23
22
60
57
54
8
98
aGC~FID is gas chromatograph-flame ionization detector.
GC-M5, IR is gas chromatograph-mass spe
NOTE: Blanks indicate no reported data.
GC-M5, IR is gas chromatograph-mass spectroscopy and infrared analysis, respectively.
Levels of benzene in bodies of water are also presented in a re-
port on potential ocean pollutants (2) . Benzene has been iden-
tified in drinking water in three United States locations (from
the Mississippi and Potomac Rivers). Levels were approximately
2.0 ppb. In one EPA study of organic compounds in drinking water
of 10 cities, benzene was detected in water from four cities
(18) Smith, H. M. Qualitative and Quantitative Aspects of Crude
Oil Composition. Bulletin 642, U.S. Department of the
Interior, Bureau of Mines, Washington, D.C., 1968.
(19) Howard, P- H., and P- R. Durkin. Sources of Contamination,
Ambient Levels, and Fate of Benzene in the Environment.
EPA-560/5-75-005, U.S. Environmental Protection Agency.-
Washington, D.C., December 1974. 73 pp.
22
-------
at concentration levels of 1.0 mg/m3 to 3.0 mg/m3. Benzene has
also been identified as a component of subsurface water, reach-
ing concentrations of 10.4 ppm in one subsurface brine and up to
24 ppm in another area having extensive oil and gas deposits.
Levels of light aromatics in marine waters near oil production
platforms have been reported to be in the 0.1 ppb to 0.7 ppb
range, with average levels being less than 1 ppb. No data have
been found on levels of benzene in soil, wildlife, and fish (2).
Population at Risk
Production and process consumption of benzene are generally
localized in the Texas Gulf area and in the Northeast; however,
the presence of benzene in gasoline gives it nationwide distri-
bution. The scarce data that currently exist indicate that most
Americans are probably exposed continuously to very low levels
of benzene. Persons that live and work in areas of major ben-
zene production and consumption obviously are exposed to larger
concentrations. Until definitive studies are made concerning
true ambient levels and the actual risks involved with such
exposure, no estimate should be made of the number of people
currently at risk from exposure to benzene emissions.
HEALTH EFFECTS
Benzene has long been recognized as a poison if ingested in large
quantities. The effects of nonlethal doses, including long-term
illnesses, are not as fully understood; however, information
on benzene's effects on both humans and animals is available.
Effects on Humans
Numerous fatalities from occupational benzene poisoning have been
reported since the early 1900's. After inhalation or ingestion,
benzene is absorbed rapidly by the blood. At nonlethal concen-
trations, a variety of human central nervous system disorders are
observed, depending upon the extent of exposure. These maladies
include euphoria followed by giddiness, headache, nausea and
staggering gait, as well as fatigue, insomnia, dizziness, and
unconsciousness. Observed damage to the human blood-forming
system includes anemia, reduction in platelet numbers, and
depression of the white blood cell count.
Oral ingestion can cause local irritation of the mucous mem-
branes, bronchitis, pneumonia, signs and symptoms of systemic
intoxication, and collapse (20). Skin exposure may cause blis-
ters. A scaly dermititis results from prolonged exposure.
(20) Criteria for a Recommended Standard: Occupational Exposure
to Benzene. U.S. Department of Health, Education and
Welfare, Public Health Service Center for Disease Control,
Washington, D.C., 1974.
23
-------
Results of several tests on humans are reported in the litera-
ture (20). The current lowest lethal concentration (LCLo) is
20,000 ppm for 5 min (21). The lowest toxic concentration
(TCLQ) reported for humans is 210 ppm.
Chronic benzene exposure also has resulted in chromosome aberra-
tions in human lymphocytes. As early as the 1930's, benzene was
suspected in cases of leukemia. Available epidemiological data
indicate that the compound does induce leukemia although the
data cannot be considered to constitute unequivocal evidence that
benzene acting alone is leukemogenic. There currently seems to
be no typical response in the blood to chronic exposure at low
levels (22). In one study, no correlation between the extent of
exposure and the severity of the benzene poisoning was reported
to exist (20). Results of similar studies are also reported in
this work. Most recently, National Institute of Occupational
Safety and Health (NIOSH) studies in two Ohio rubber plants
revealed incidences of leukemia five times higher than normal
(23). This report prompted current Occupational Safety and
Health Administration (OSHA) emergency standards. Although
benzene is suspected to cause leukemia, no fully convincing
experimental proof exists.
There are other chronic effects of exposure to benzene. Muta-
tions in the pulmonary system and in bone marrow have been
observed, along with liver, kidney, and lung damage, hormone
alteration, and bone marrow hyperplasia (1).
Effects on Animals
Acute effects on animals are similar to those on humans. Acute
toxicity data currently available is summarized in Table 8 (1,
21). Much of the work done on animals is summarized in Refer-
ence 20.
Most testing in the studies of chronic effects of benzene has
been performed on animals. The results of carcinogenity tests
on mouse skin indicate the lowest toxic dose is 1,232 mg/kg for
a 52-wk exposure (1). Studies of both long- and short-term
(21)Markle, R. A., et al. Potentially Toxic and Hazardous
Substances in the Industrial Organic Chemicals and Organic
Dyes and Pigments Industry- Contract 68-02-1323, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, October 1976.
(22) Industrial Hygiene and Toxicology, Volume II. F. A. Patty,
ed. John Wiley & Sons, Inc., New York, New York, 1962.
2305 pp.
(23) Benzene Emerging Standard Set by OSHA. Chemical &
Engineering News, 55(19):4, 1977.
24
-------
TABLE 8. TOXICITY DATA FOR BENZENE (1, 21)
Acute
toxicity Dosage Animal Route
LD50 468 mg/kg Mouse Intraperitoneal
1,150 mg/kg Rat Intraperitoneal
3,800 mg/kg Rat Oral
4,700 mg/kg Mouse Oral
LD 530 mg/kg Guinea pig Intraperitoneal
1,400 mg/kg Frog Subcutaneous
2,000 mg/kg Dog Oral
LC50C 10,000 ppm/7 hr Rat Inhalation
Calculated dose expected to kill 50% of the exposed
population.
Lowest reported dose to cause death.
Calculated concentration expected to kill 50% of the
exposed population.
inhalation of benzene vapors by dogs show that benzene concen-
trates in ,fat, bone marrow, urine, and red blood cells following
a rapid distribution through the body (20).
Attempts by the National Cancer Institute and others to induce
leukemia in animals with benzene have not been successful.
However, results of inhalation experiments with mice, the
species most susceptible to leukemia, are not yet available.
Many researchers have concluded that more study is definitely
needed (20).
25
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SECTION 5
CONTROL TECHNOLOGIES
Benzene emissions can be controlled by preventing the release of
the pollutant or by treating the waste streams. Various techni-
ques of implementing these ideas have been developed. Applicable
control methods, their efficiencies, and the economics of their
use are briefly described.
EMISSION SOURCE CONTROL METHODS
Different control methods have been developed for different
sources of emissions. The following are generally applicable to
any process containing emissions of benzene.
Fugitive Emissions
Most fugitive hydrocarbon emissions can be controlled only by
regular inspection, maintenance, and good housekeeping. For
sources such as pump and compressor seals, wastewater systems,
and storage tanks, specific devices have been designed to help
control emissions. Other sources require major equipment addi-
tions such as installing an integrated vapor recovery/flare
system for all vents and relief valves (24, 25).
Catalyst Regeneration
Several of the processes for producing or using benzene employ
solid catalysts, which require periodic regeneration. Any
unburned benzene (or other hydrocarbon) in the flue gas could
be removed by incineration in a heater firebox or smoke plume
burner. These devices are not usually used due to the infre-
quency of catalyst regenerations.
(24) Rosebrook, D. D., et al. Sampling Plan for Fugitive Emis-
sions from Petroleum Refineries. Radian Contract 200-144,
Task 6, Radian Corporation, Austin, Texas, January 1977-
(25) Control Techniques for Volatile Organic Emissions from
Stationary Sources. Publication No. AP-68, Project 220-
187-12, U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina. (Draft report submitted
to the EPA by Radian Corporation, July 1977.)
26
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Vents
Benzene can be continuously emitted through vents. Emissions
can be eliminated by routing them to an integrated vapor recov-
ery or incineration system, wet scrubbing in an absorber, a com-
bination scrubbing-incineration system, or an adsorption system.
Aqueous Discharge Prevention
Aqueous emissions are often generated by water wash of products,
water quenches, steam stripping.- and vacuum production using
steam ejectors and barometric condensers. In some cases, the
initial production of such benzene-contaminated streams can be
prevented. For example, a stripping column can replace water
wash. Vacuum pumps, surface condensers, and oily water inciner-
ators can eliminate the contaminated effluent from ejectors and
barometric condensers (26).
Aqueous Discharges Treatment
Aqueous effluents from benzene processes can be treated in stand-
ard wastewater treatment units. If benzene was the only pollu-
tant, a covered hydrocarbon/water separator would be sufficient
(26). Most benzene processes are part of a large refinery or
chemical plant, which generally has primary, secondary.- and, often,
tertiary treatment systems. These systems are more complex than
can be described in this document (24, 25, 26).
Organic Sludges
A benzene-contaminated sludge is often a byproduct of solvent
extraction processes for aromatics purification. Standard prac-
tice is to dry it and use it as landfill; however, incineration
is an alternative (25, 27) When the sludge is dried an unknown
amount of benzene could be released to the air.
Control of Storage Losses
Although not generally applied, there are several methods of
controlling emissions from benzene storage. Replacement of old
(26) Sittig, M. Pollution Control in the Organic Chemical Indus-
try. Noyes Data Corporation, Park Ridge, New Jersey, 1974.
304 pp.
(27) Cavanaugh, E. C., J. D. Colley, P. S. Dzierlenga, J. M.
Felix, D. C. Jones, and T. P. Nelson. Environmental Problem
Definition for Petroleum Refineries, Synthetic Natural Gas
Plants, and Liquefied Natural Gas Plants. EPA-600/2-75-068,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, November 1975. 476 pp.
27
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floating roof seals with newer double seals will reduce emis-
sions by 50% to 75% (28) . Use of pressure tankage for new con-
struction is also possible as a control method since emissions
from pressure tanks are virtually negligible. Storage emissions
control is discussed in Reference 25.
Transportation of Benzene
Losses resulting from benzene transportation are very similar to
losses resulting from gasoline transportation. Controls can be
applied at marine terminals, tank truck terminals, and rail car
terminals. Modified loading procedures (submerged or bottom
loading) in conjunction with vapor recovery devices are the prin-
cipal technologies available. Detailed descriptions of such
methods are found in Reference 25.
Motor Vehicles
Benzene emissions due to gasoline evaporation at service stations
can be controlled in ways similar to those used in other loading
and unloading operations. Both vapor recovery systems and modi-
fied loading methods can be applied to bulk handling of gasoline.
Vapor recovery units on gasoline pumps can significantly reduce
emissions (25, 29).
Exhaust emissions of benzene are controlled primarily by carbu-
retion adjustment. This will allow more complete combustion of
the hydrocarbons found in gasoline.
The emergence of the catalytic converter is expected to have an
impact on benzene emissions from motor vehicle exhaust. For•
example, in exhaust sample testing the converter was able to
reduce benzo(a)pyrene emissions (a difficult to control poly-
cyclic organic), by an order of magnitude from 1968 emission-
controlled vehicles. Actual figures were from 2 to 6 mg/m3 down
to 0.5 mg/m3 of fuel consumed (30). If such a high degree of
control is achieved with polycyclic organics, reduction in ben-
zene emissions would also be expected from catalytic converters.
(28) American Petroleum Institute, Evaporative Loss Committee.
Evaporative Loss from Floating Roof Tanks. Bulletin 2517,
Washington, D.C., 1972.
(29) Burklin, C. E., E. C. Cavanaugh, J. C. Dickerman, and S. R.
Fernandes. A Study of Vapor Control Methods for Gasoline
Marketing Operations, Volume I. EPA-450/3-75-046-9, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, April 1975. 215 pp.
(30) Preferred Standards Path Report for Polycyclic Organic
Matter. Draft report, U.S. Environmental Protection
Agency, Durham, North Carolina, October 1974. 107 pp.
28
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Oil Spills
Accidental spills of oil (or benzene) are virtually unavoidable.
Several steps can be taken whenever a benzene-containing hydro-
carbon is spilled into a body of water (10) . These include noti-
fying the nearest users of the water; removing the source of the
spill from the water; skimming of hydrocarbon liquids from the
surface; treating the water with activated carbon, a coagulant,
and a polyelectrolyte (where feasible); and removing the resul-
tant floe. These techniques are generally more applicable to
inland waterways than to oceans.
CONTROL EFFICIENCIES
The efficiency of any method of controlling benzene emissions
depends on such factors as operating conditions, quality and
quantity of the waste stream, and state of repair of the system.
Table 9 lists present producers of maleic anhydride (a benzene
consumer industry), their control technology, and reported con-
trol efficiencies (31).
Incineration
Incineration is an acceptable form of controlling benzene emis-
sions from sludges and concentrated hydrocarbon liquids. Incin-
eration can be accomplished in afterburners (direct flame and
catalytic) and boilers. Properly designed and operated inciner-
ators usually achieve organic vapor removal efficiencies in
excess of 95%.
Adsorption
Benzene can by physically adsorbed from a gas stream by activa-
ted carbon. Such adsorption is usually more efficient than
incineration for removing organics in concentrations lower than
200 ppm. Efficiencies are usually around 100% (25).
Absorption (Scrubbing)
Absorption or scrubbing involves the dissolution of certain
vapor-phase components into a liquid solvent. Benzene is re-
moved from gas streams in such a unit operation. When the con-
centration of benzene in the gas is low, large quantities of
absorbent and long contact times are required for adequate re-
moval. For this reason, scrubbers are often used in series with
incinerators.
(31) Lewis, W. A. Jr., G. M. Rinaldi, and T. W. Hughes. Source
Assessment: Maleic Anhydride. Contract 68-02-1874, U.S.
Environmental Protection Agency, Industrial Environmental
Research Laboratory, Cincinnati, Ohio. 118 pp.
29
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TABLE 9. CONTROL DEVICES AND REPORTED CONTROL EFFICIENCIES
FOR THE MALEIC ANHYDRIDE INDUSTRY (31)
Company
Amoco Chemicals Corp.
Ashland Oil, Inc.
Denka Chemical Corp.
Koppers Co.
Monsanto Co .
Reichold Chemicals,
Inc.
Flaking
pelletizing,
and packaging
NR9
_b
Scrubberc
Scrubber c
Scrubber0
_b
Emission points
Product recovery
scrubber
NR
Scrubberc
Thermal incinera-
tor 93%, 95%
Thermal incinera-
tor 97%e
_f
Carbon
absorber 84%d
Storage
tank vents
NR
Floating roof
tanksc
Floating roof
tanks0
Return ventsc
Scrubber c
Scrubber,
conservation
Tenneco, Inc.
U.S. Steel Corp.
_f
Scrubberc
_f
Catalytic incin-
erator 85%"
vents1-
Scrubber,
conservation
ventsc
Floating roof
tanks0
aNot reported. Hydrocarbon control efficiency.
K G
Plant does not have the emission Carbon monoxide control efficiency.
P°int- No control.
Control efficiency not reported.
Vapor Recovery
Benzene loss due to fugitive emissions from pressure relief
devices, loading and unloading operations, and gasoline market-
ing operations can be minimized by vapor recovery systems.
These allow the vapors to be collected and routed to knockout
drums, condensers, refrigeration units, absorbers, or simply the
tank from which they came. Control efficiencies are between 85%
and 100%, depending upon the source of the emissions; gasoline
marketing emissions are the most difficult to control (25).
Alternate Loading Methods
Bulk handling of benzene-containing hydrocarbons i§ subject to
losses due to loading and unloading. Procedure changes in load-
ing practices can reduce emissions by the amounts shown below.
30
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Emission source Percent reduction
Marine terminals 60 to 80
Rail and tank truck terminals 40 to 60
Gasoline service stations
The preferred methods include vapor- freeing ballasted and empty-
ship cargo tanks at sea, slower tank loading, submerged filling,
and bottom loading.
Wastewater Treatment
Treatment of benzene-contaminated water generally involves pri-
mary separation followed by secondary and possibly tertiary
treatment. Hydrocarbon removal efficiency for the primary sepa-
rations step is generally between 70% and 90% (24) . No data
are known for benzene removal efficiencies in any treatment step.
Standard texts on wastewater treatment plant design are readily
available, such as Metcalf and Eddy (32) .
Storage Vessels
Installation of double seals on floating roof tanks can reduce
emissions by 50% to 75% (28) . Construction of pressure storage
vessels would virtually eliminate emissions.
(32) Metcalf, L., and H. P. Eddy. Wastewater Engineering
Collection, Treatment, Disposal. McGraw-Hill Book
Company, New York, New York, 1972. 734 pp.
31
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SECTION 6
REGULATORY ACTION
In 1974 NIOSH (National Institute of Occupational Safety and
Health) published a criteria document for occupational exposure
to benzene which recommended adherence to the existing Federal
standard of 10 ppm as a time-weighted average with a ceiling of
25 ppm. OSHA has proposed a reduction of the standard to a
1 ppm 8-hr time-weighted average with a ceiling of 5 ppm over a
15-min period. An OSHA (Occupational Safety and Health Adminis-
tration) Emergency Temporary Standard has been stayed pending
a hearing on a request for injunction. NIOSH is conducting
retrospective studies of benzene mortality and airborne benzene
levels in service stations; however, the OSHA regulations would
apply to sources with only 5 or more employees; thus service
stations remain unregulated.
EPA has initiated an air-monitoring program which will determine
benzene levels in selected areas. Qualitative results obtained
to date indicate widespread low-level benzene contamination.
Studies are in progress to document the extent of hazard and the
best regulatory approach under the Clean Air Act. EPA has con-
ducted a limited survey of drinking water supplies in which
benzene was identified in some samples and has begun a more
extensive survey which will seek out benzene as well as a number
of other pollutants. Benzene has been designated a priority
pollutant under the FWPCA (Federal Water Pollution Control Act),
and ocean dumping is already strictly regulated. Additional
water quality criteria for benzene are anticipated from EPA
under the FWPCA Consent Decree by July 1978. The Consumer
Products Safety Commission is awaiting results of the National
Academy of Sciences study on the health effects of benzene to
determine if the results warrant further action.
32
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REFERENCES
1. Dorigan, J. Scoring of Organic Air Pollutants: Chemistry
Production and Toxicity of Selected Synthetic Organic
Chemicals. Mitre Corporation, September 1976.
2. Ocean Affairs Board, National Research Council. Assessing
Potential Ocean Pollutants. Report No. 0-309-02325-4, U.S.
Environmental Protection Agency and National Science
Foundation, Washington, D.C., January 1975. 456 pp.
3. Directory of Chemical Producers—U.S.A. Chemical Informa-
tion Services, Stanford Research Institute, Menlo Park,
California, 1977- 1059 pp.
4. Parsons, T. B., et al. Industrial Process Profiles for
Industrial Use: Basic Petrochemicals Industry, Chapter 5.
Contract 68-02-1319, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, January 1977-
5. Refining Handbook. Hydrocarbon Processing, 53(9):192, 1974,
6. Petroleum Processing Handbook, Chapter 3. W. F. Bland and
R. L. Davidson, eds. McGraw-Hill Book Co., New York, New
York, 1967. pp. 1-152.
7. Chemical Origins and Markets, Fifth Edition, G. M. Lawler,
ed. Chemical Information Services, Stanford Research
Institute, Menlo Park, California, 1977. 118 pp.
8. Wilkins, G. E. End Use Patterns for Significant Organic
Chemicals. Contract 68-02-1319, U.S. Environmental Pro-
tection Agency, Research Triangle Park, North Carolina,
July 1976.
9. Ponder, T. C. Benzene: Outlook Through 1980. Hydrocarbon
Processing, 55(11):217-218, 1976.
10. Dawson, G. W., A. J. Shuckrow, and W. H. Swift. Control of
Spillage of Hazardous Polluting Substances. Contract
14-12-866 (PB 197 596), U.S. Department of the Interior,
Federal Water Quality Administration, Washington, D.C.,
November 1970. 96 pp.
33
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11. Eimutis, E. C., and R. P. Quill. Source Assessment: Non-
criteria Pollutant Emissions. EPA-600/2-77-107e, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, July 1977. 113 pp.
12. Compilation of Air Pollutant Emission Factors, Second
Edition (with Supplements 1-7). Publication No. AP-42,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, 1973.
13. Industrial Process Profiles for Environmental Use: Chapter
6, The Organic Chemicals Industry, Part I. (Draft). Contract
68-02-1320, Task 17 and Contract 68-02-1325, Task 70, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina.
14. Burklin, C. E., and R. L. Honerkamp. Revision of Evapora-
tive Hydrocarbon Emission Factors. Radian Project 100-
086-01, Radian Corporation, Austin, Texas, June 1976.
15. Air Pollution Engineering Manual, Second Edition. J. A.
Danielson, ed. Publication No. AP-40, U.S. Environmental
Protection Agency, Research Triangle Park, North Carolina,
May 1973. 987 pp.
16. Burklin, C. E., E. C. Cavanaugh, J. C. Dickerman, S. R.
Fernandes, and G. C. Wilkins. Control of Hydrocarbon
Emissions from Petroleum Liquids. EPA-600/2-75-042, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, September 1975. 245 pp.
17. Benzene from Gasoline Evaporation is "Significant Health
Hazard", EDF says. Environmental Report 1977, 1363.
18. Smith, H. M. Qualitative and Quantitative Aspects of Crude
Oil Composition. Bulletin 642, U.S. Department of the
Interior, Bureau of Mines, Washington, D.C., 1968.
19. Howard, P. H., and P. R. Durkin. Sources of Contamination,
Ambient Levels, and Fate of Benzene in the Environment.
EPA-560/5-75-005, U.S. Environmental Protection Agency,
Washington, D.C., December 1974. 73 pp.
20. Criteria for a Recommended Standard: Occupational Exposure
to Benzene. U.S. Department of Health, Education and
Welfare, Public Health Service Center for Disease Control,
Washington, D.C., 1974.
21. Markle, R. A., et al. Potentially Toxic and Hazardous
Substances in the Industrial Organic Chemicals and Organic
Dyes and Pigments Industry. Contract 68-02-1323, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, October 1976.
34
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22. Industrial Hygiene and Toxicology, Volume II. F. A. Patty,
ed. John Wiley & Sons, Inc., New York, New York, 1962.
2305 pp.
23. Benzene Emerging Standard Set by OSHA. Chemical & Engineer-
ing News, 55 (19):4, 1977.
24. Rosebrook, D. D., et al. Sampling Plan for Fugitive Emis-
sions from Petroleum Refineries. Radian Contract 200-144,
Task 6, Radian Corporation, Austin, Texas, January 1977.
25. Control Techniques for Volatile Organic Emissions from
Stationary Sources. Publication No. AP-68, Project 220-187-
12, U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina. (Draft report submitted to the EPA
by Radian Corporation, July 1977.)
26. Sittig, M. Pollution Control in the Organic Chemical Indus-
try. Noyes Data Corporation, Park Ridge, New Jersey, 1974.
304 pp.
27. Cavanaugh, E. C., J. D. Colley, P. S. Dzierlenga, J. M.
Felix, D. C. Jones, and T. P- Nelson. Environmental Problem
Definition for Petroleum Refineries, Synthetic Natural Gas
Plants, and Liquified Natural Gas Plants. EPA-600/2-75-068,
U.S. Environmental Protection Agency, Research Triangle
Park, North Carolina, November 1975. 476 pp.
28. American Petroleum Institute, Evaporative Loss Committee.
Evaporative Loss from Floating Roof Tanks. Bulletin 2517,
Washington, D.C., 1972.
29. Burklin, C. E., E. C. Cavanaugh, J. C. Dickerman, and S. R.
Fernandes. A Study of Vapor Control Methods for Gasoline
Marketing Operations, Volume I. EPA-450/3-75-046-9, U.S.
Environmental Protection Agency, Research Triangle Park,
North Carolina, April 1975. 215 pp.
30. Preferred Standards Path Report for Polycyclic Organic
Matter. Draft report, U.S. Environmental Protection
Agency, Durham, North Carolina, October 1974. 107 pp.
31. Lewis, W. A. Jr., G. M. Rinaldi, and T. W. Hughes. Source
Assessment: Maleic Anhydride. Contract 68-02-1874, U.S.
Environmental Protection Agency, Industrial Environmental
Research Laboratory, Cincinnati, Ohio. 118 pp.
32. Metcalf, L., and H. P. Eddy- Wastewater Engineering
Collection, Treatment, Disposal. McGraw-Hill Book
Company, New York, New York, 1972. 734 pp.
35
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GLOSSARY
aromatic: Designating any of a series of benzene ring compounds,
fugitive emission: Gaseous or particulate emissions from
industry-related operations that escape to the atmosphere
without passing through a primary exhaust system.
miticide: Material used primarily in the control of plant-feed-
ing mites, especially spider mites.
olefin: Any series of unsaturated open-chain hydrocarbons con-
taining one double bond.
pyrolysis: Decomposition of a compound by the action of heat
alone.
36
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-79-210d
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Status Assessment of Toxic Chemicals: Benzene
5. REPORT DATE
December 1979
issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
T.R. Blackwood, J.C.
L.D. Zeagler
8. PERFORMING ORGANIZATION REPORT NO.
Ochsner
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Monsanto Research Corp Radian Corp
1515 Nichols Road 8500 Shoal Creek Blvd
Dayton, Ohio 1+5^07 P.O. Box 99kQ
Austin, Texas 78766
10. PROGRAM ELEMENT NO.
IAB6oh
11. CONTRACT/GRANT NO.
68-03-2550
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Lab. - Cinn, OH
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 1*5268
13. TYPE OF REPORT AND PERIOD COVERED
Task Final 11/77 - 12/77
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
IERL-Ci project leader for this report is Dr. Charles Frank, 513-68U-U^8l.
16. ABSTRACT
Benzene is one of the most ubiquitous organic chemicals, widely
employed as a solvent, as a fuel component, and for the synthesis
of other organic chemicals. This report details the emission of
benzene from industrial sources and from the largest source of all,
the operation of motor vehicles. Descriptions of the health hazards
of benzene exposure are included, and both current and anticipated
regulations are listed. The report is concluded with recommendations
of areas for further study.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Aromatic Hydrocarbons, Aromatic Monocyclic
Hydrocarbons, Hydrocarbons, Unsaturated
Hydrocarbons, Chlorobenzenes
Organics, Organic
Chemical Synthesis
68A
68D
68G
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)
Unclassified
21. NO. OF PAGES
49
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
37
iUS GOVEBIIIIENT PRINI1NG OfflCE 1980-657-146/5510
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