Petroleum and Coal Products Manufacturing Industry Practices and
Environmental Characterization
US Environmental Protection Agency
Office of Land and Emergency Management
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Introduction
Operational and decommissioning practices in industrial sectors and their associated firms can
ultimately affect the ability of individual firms to responsibly minimize their impact on human health and
the environment. To consider the potential for releases as part of its decision making, EPA prepared this
high-level review of industry practices and the environmental profile of the Petroleum and Coal Product
Manufacturing Industry, which includes a summary of relevant operational and decommissioning
materials and wastes.
This document endeavors to review how current Petroleum and Coal Product Manufacturing Industry
practices have affected the non-permitted releases of hazardous substances into the environment. It
also discusses how the nature and frequency of releases and other impacts may have changed over
time. As documented in the 2010 Advance Notice of Potential Rulemaking (ANPRM)1, facilities in the
Petroleum and Coal Products Manufacturing Industry generate significant quantities of hazardous
wastes, which may increase the risk of releases of hazardous substances.
Wastes
Hazardous wastes generated by the Petroleum and Coal Products Manufacturing industry can contain
significant concentrations of certain toxic chemicals (benzene, arsenic, and polycyclic aromatic
hydrocarbons (PAHs)). Sites contaminated by the industry typically contain several different
contaminants, including toxic organics, such as benzene, polychlorinated biphenyls (PCBs), phenol, and
volatile organic hydrocarbons (VOCs); and heavy metals, such as barium, cadmium, chromium, copper,
lead, selenium, and zinc. Other substances beyond those listed here may also have been released from
facilities in the industry. Air emissions and any associated human health and environmental impacts are
not considered in this document, as they rarely lead to the CERCLA and RCRA removal and clean up
liabilities relevant to CERCLA 108(b) potential requirements. Additional information on releases for a
portion of this industry is also available in the EPA "Profile of the Petroleum Refining Industry"2.
Waste from the Petroleum and Coal Product Manufacturing Industry arises at each step of the
production cycle. This characterization review concerns only the operation and decommissioning steps
of direct relevance to the Petroleum and Coal Product Manufacturing Industry. Operation of any facility
in this industry requires use of a variety of nonhazardous materials, including paper, cardboard, wood,
aluminum, containers, packaging materials, office waste, municipal trash etc. Potentially hazardous
materials are also frequently used. These materials can include sandblast media, fuels, paints, spent
vehicle and equipment fluids (e.g., lubricating oils, hydraulic fluids, battery electrolytes, glycol coolants)
among others. Hazardous materials may include, but are not limited to, asbestos or mercury containing
materials, compressed gases used for welding and cutting, dielectric fluids, boiler bottom ash, and oils.
Process fluids can be either hazardous or non-hazardous, and can include oily water, spent solvents,
1 https://wvyyy.federalregister.gov/documents/2010/01/06/E9-31399/identification-of-additionaj-cjasses-of-
facilities-for-development-of-financial-responsibility
2 EPA Sector Notebook "Profile of the Petroleum Refining Industry". Sep 1995. EPA/310-R-95-013
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chemical cleaning rinses, cooling water, wash and makeup water, sump and floor discharges, oily water
seperator fluids, boiler blowdown, and water from surface impoundments. Other materials beyond
those listed here may be used in the operation of Petroleum and Coal Product Manufacturing Industry
facilities.
For Petroleum and Coal Product Manufacturing Industry facilities, decommissioning will likely occur
soon after the end of a plant's operating life. Decommissioning wastes will generally be those associated
with demolition. Some may pose special residual hazards. Where onsite landfills and surface
impoundments are used during operation, compliant and protective closure can be complex and
challenging.
Industries and their Subsectors
The North American Industry Classification System (NAICS) Subsector Code 324 - Petroleum and Coal
Products Manufacturing - is "based on the transformation of crude petroleum and coal into usable
products. The dominant process is petroleum refining that involves the separation of crude petroleum
into component products through such techniques as cracking and distillation. In addition, this
subsector includes establishments that primarily further process refined petroleum and coal products
and produce products, such as asphalt coatings and petroleum lubricating oils." Within this classification
the following subsectors are listed as:
Subsector 324: Petroleum and Coal Products Manufacturing
Industry Group 3241: Petroleum and Coal Products Manufacturing
Industry 32411: Petroleum Refineries
6 Digit Code(s) NAICS 324110: Petroleum Refineries
Industry 32412: Asphalt Paving, Roofing, and Saturated Materials Manufacturing
6 Digit Code(s) NAICS 324121: Asphalt Paving Mixture and Block Manufacturing
6 Digit Code(s) NAICS 324122: Asphalt Shingle and Coating Materials
Manufacturing
Industry 32419: Other Petroleum and Coal Products Manufacturing
6 Digit Code(s) NAICS 324191: Petroleum Lubricating Oil and Grease
Manufacturing
6 Digit Code(s) NAICS 324199: All Other Petroleum and Coal Products
Manufacturing
Each of the sections that follow describes operating and decommissioning Petroleum and Coal Product
Manufacturing industry subsector waste management methods in the United States and provides a brief
overview description of how they are implemented. Some types of Petroleum and Coal Product
Manufacturing Industry subsectors require fewer hazardous substances and generate less hazardous
waste than others. Unique characteristics within the subsectors are covered below.
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Industry 32411: Petroleum Refineries and NAICS 324110: Petroleum Refineries Subsector.
This subsector comprises establishments primarily engaged in refining crude petroleum into refined
petroleum. Petroleum refining involves one or more of the following activities: fractionation, distillation
of crude oil, cracking hydrotreating, combination/blending processes, manufacturing and transport. The
Petroleum Refineries industry consists of facilities that produce gasoline, gasoline blending stocks,
naphtha, kerosene, distillate fuel oils, residual fuel oils, lubricants, petcoke3, or asphalt (bitumen) by the
distillation of petroleum or the re-distillation, cracking, or reforming of unfinished petroleum
derivatives. 4
In 2000, it was reported that 45 percent of all refineries at that time were within three miles of
population centers containing 25,000 or more people, and 26 percent were within three miles of
population centers containing 50,000 or more people.5 On average, U.S. refineries produce, from a 42-
gallon barrel of crude oil, about 19 to 20 gallons of motor gasoline, 11 to 12 gallons of distillate fuel,
most of which is sold as diesel fuel, and 4 gallons of jet fuel. More than a dozen other petroleum
products are also produced in refineries. Petroleum refineries also produce liquids the petrochemical
industry uses to make a variety of chemicals and plastics.6
Refinery Processes
A modern refinery is a highly complex and integrated system separating and transforming crude oil into
a wide variety of products, including transportation fuels, residual fuel oils, lubricants, and many other
products. The simplest refinery type is a facility in which the crude oil is separated into lighter and
heavier fractions through the process of distillation. These small operations consist only of distillation
capacity (i.e., no reforming or converting capacities) and make a limited number of products. Modern
refineries have developed much more complex and integrated systems7 in which hydrocarbon
compounds are not only distilled but are also converted and blended into a wider array of products.
The process of oil refining involves a series of steps that includes separation and blending of petroleum
products. The five major processes are briefly described below:8
• Separation processes: These processes involve separating the different fractions/ hydrocarbon
compounds that make up crude oil based on their boiling point differences. Crude oil generally
is composed of the entire range of components that make up gasoline, diesel, oils and waxes.
Separation is commonly achieved by using atmospheric and vacuum distillation. Additional
processing of these fractions is usually needed to produce final products.
3 Petroleum Coke: Industry and Environmental Issues, Congressional Research Service, 29 Oct 2013
4Refinery sector industry profile accessed at https://www.epa.gov/ghgreporting/ghgrp-refineries
5 EPA OIG report 2004-P-00021 "EPA needs to Improve Tracking of National Petroleum Refinery Compliance
Program Progress and Impacts", June 22, 2004
6 Refining Crude Oil, US Energy Information Administration accessed at
https://www.eia.gov/energyexplained/index.php?page=oil refining
7 Ernest Orlando Lawrence Berkeley National Laboratory report LBNL-56183 of February 2005, E. Worrell and C. Galitsky
8 Hazardous Substance Research Center Environmental Update #12 "Environmental impact of the Petroleum Industry", June
2003
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• Conversion processes: Cracking, reforming, coking, and visbreaking are conversion processes
used to break down large longer chain molecules into smaller ones by heating or using catalysts.
These processes allow refineries to break down the heavier oil fractions into other light fractions
to increase the fraction of higher demand components such as gasoline, diesel fuels or whatever
may be more useful at the time.
• Treating: Petroleum-treating processes are used to separate the undesirable components and
impurities such as sulfur, nitrogen and heavy metals from the products. This involves processes
such as hydrotreating, de-asphalting, acid gas removal, desalting, hydrodesulfurization, and
sweetening.
• Blending/combination processes: Refineries use blending/combination processes to create
mixtures with the various petroleum fractions to produce a desired final product. An example of
this step would be to combine different mixtures of hydrocarbon chains to produce lubricating
oils, asphalt, or gasoline with different octane ratings.
• Auxiliary processes: Refineries also have other processes and units that are vital to operations
by providing power, waste treatment and other utility services. Products from these facilities are
usually recycled and used in other processes within the refinery and are also important to
minimizing water and air pollution. A few of these units are boilers, wastewater treatment, and
cooling towers.
Refinery Materials and Wastes
Wastes and emissions are generated by petroleum refineries. As outlined in the ANPRM, "refineries
tend to be operated for decades, there is a long timeframe for potential releases and exposure of
hazardous substances to occur. In addition, because of their need for large amounts of cooling water for
operations, refineries tend to be located near navigable waterways or on the seashore, which likely
increases the potential to impact groundwater, surface water, aquatic biota, and aquatic vegetation.
Other impacts to terrestrial vegetation, wetlands, wildlife, soils, air, cultural resources, and humans that
use these resources recreationally or for subsistence also are likely."
Petroleum refineries account for significant hazardous waste generation, including but not limited to,
primary and secondary sludges, spent catalysts, filter clays and cakes, sour water, heavy ends
(distillation bottoms), dissolved air/nitrogen flotation (DAF/DNF), flotation debris, waste soils, oily
sludge, tank bottom sludge, clarified slurry oil, slop oil emulsion solids, spent lime, storm water silt,
catalyst and coke fines, and tank bottoms9. Two EPA sector performance reports from 200810 and
200911 list the top petroleum refinery 2005 and 2006 disposals as ammonia, asbestos, benzene,
ethylbenzene, lead, molybdenum trioxide, toluene, xylene and zinc. A detailed review of refinery
processes and associated wastes generated is shows on Figure 1 below.
9 Assessment of Hazardous Waste Practices in the Petroleum Refining Industry, US EPA, June 1976, PB-259 097
10 2008 Sector Performance Report, EPA 100-R-08-002, September 2008, page 78
11 2009 Supplement to 2008 Sector Performance Report, February 2009, page 29
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1 \hibit 15: I \ pk ;il Muterhil Outputs from Selected Petroleum
Refining Processes
Pi-orm
Air Emissions
Process Waste Water
Residual Wastes
C.rtiei aicit
Crock oil
desalting
Heatei stack gas (CO, SO,.
NO,, hydrocarbous and
paniculate*), fugitive emissions
(hydrocarbons)
f Iow=2.1 Gal/BW
Oil HjS. NH,. phenol,
high levels of
suspended solids,
dissolved solids, high
F">« il >. high
temperature.
Crade oil-desaher stodge
(iron rust. clay. sand,
water, emulsified oil and
was. metals)
Atmospheric
distillation
Vacuum
Distillation
Healer stack gas (CO. SO,.
NO,, hydrocarbons unci
particulates). vents aatl fugitive
emissions (hydrocarbons)
Steam ejector emissions
(hydrocarbons). beater snick
gas (CO. SO,. NO,,
hydrocarbons and particulates),
vents and fugitive emissions
(hydrocarbons)
f low=26.0 Galfflbl
Oil. H:S. NH,.
suspended solids,
chlorides. mercaptans.
phenol, elevated pH
Typically, little or no
residual waste generated.
Thermal
Cracking;'
Visbrealcing
Heater slack gas (CO. SO,.
NO,, hydrocarbons and
particulates,1. vents and fugitive
,aiiissiais,|h^roctrb«w),
Flow=2.0 Gal/Bbl
Oil. HjS. NH,. phenol
suspended solids. Iiiali
.PH,.B0X>^.C0D,.
Typically, little or no
residual waste generated.
Coking
Heater stack gas (CO. SO,,
NO,, hydrocarbons and
particulates). vents and ftigitive
emissions (hydrocarbons) and
decoking emissions
(hydrocarbons and
jjaniciUates).
HighpH.HjS.NH,.
suspended solids. COD,
Cote dust (carbon particles
and hydrocarbons)
Catalytic
Cracking
Heater slack gas (CO. SOx.
NO,, hydrocarbons and
particulates), fiieifive emissions
(hydrocarbons) and catalyst
regeneration (CO. NO». SQ,,
and particulates)
Flow=15.0 G»1/BM
High levels of oil.
suspended sol ids.
phenols, cvanides. H,S.
Nil,. htgh'pH. BOD."
i ni>.
Spent catalysts (metals
from crude oil and
hydrocarbons),
spent catalyst lines front
electrostatic precipitators
(aluminum silicate and
metals)
Catalytic Hydro*
cracking
1U tier stack gas (CO. S€\,
NO,, hydrocarbons and
particulates), fugitive emissions
(hydrocarbons) and catalyst
regeneration (C'O. NO,. SO,
rrtfflMM ™, ,,
FIow=2.0 Gal'Bbl
High COD. suspended
solids. H»S. relatively
low levels of BOD.
Spent catalysts fines
(utetals from crude oil and
hydrocarbons)
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Process
Air Emissions
Process Waste Wafer
Residual Wastes
¦
Hydrotreating?
Hydroprocessing
ick gas (CO. SO,.
NO,, hydrocarbons and
particulates), vents and fiigitive
emissions (hydrocarbons) and
catalvst regeneration (CO.
no;scv .
Flow-1.0 Gai/BM
MS, m„ High pH.
phenols suspended
solids. BOD. COD,
Spent catalyst fines
(aluminum silicate and
metals).
\ik viaticm
Heater stack gas (CO, SO,,
NO*, hydrocarbons and
particulates), vents and fugitive
emissions (hydrocarbons)
Low pl-l suspended
solids, dissolved .solids.
COD. ftS. spent
sulfuric acid.
Neutralized alkyiation
sludge (sulfuric acid or
calcium fluoride,
hydrocarbons).
Isoijiettzatioii
Heater slack gas (CO. SO,.
NO,, hydrocarbons and
particulates). HO (pciientially
in. light aids), veins and
fugitive emissions
(hydrocarbons)
Low pH. chloride salts.
caustic wash, relatively
low H;S and NH,.
t akiuBtt chloride sludge
from neutralized HC1 gas.
Polymerization
H,S from caustic washing
H;S, NH). caustic wash,
uiercaptans and
3iiiiii0iiiii. high pH.
Spent catalyst containing
phosphoric acid.
1 ti.ll.-U"
Reforming
Heater stack gas (CO. SO,.
NO,, hydrocarbons and
particulates), fugitive emissions
(hydrocarbous) and catalyst
regeneration (CO. NO,. SO,)
Flow=6.0 Gai/BW
High levels oil
suspended solids. COD.
Relatively low liS.
Spent catalyst fines from
electrostatic precipitators
(alumina silicate and
metals).
'cm
aetion
Fugitive solvents
Oil unci solvents
Little or no residual wastes
Dewasiiig
Fugitive solvents, beaters
Oil and solvents
Little or no residual wastes
ante
IK' t-l'ii tl'KCi
*¦ * " ¦ t- *¦**" • " " *•
Healer stack gas (CO. SOs.
Mt\. hydrocarbons and
particulates). fltgitive propane
Oil and propane
Little or no residual wastes
lie ("niz
Vents and fugitive emissions
(hydrocarbons and disulfides).
Little or no wastewater
generated.
Spent Merox caustic
solution. waste oM-clisttlflcle
1111X11
Wastewater
treatment
Fugitive emissions NH,.
unci hydrocarbons)
Not Applicable
AW separator sludge
(phenols, metals and oil),
chemical precipitation
sludge (clieiiiical
coagulants, oil). DAF
floats, biological sludges
(ntetals. oil. suspended
solids), spent Mine.
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Process
Ail* Emissions
Pi .h t'^ Waste Water
Residual Wastes
(.tin 1 ;ttc
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Petroleum Refining Process Flow Chart
This flow chart illustrates the petroleum refinery process, potential releases, potential release
points, and the major applicable environmental regulations.
PtCoteim Refinery
Process Row
(CO, SCK NCX fytluuftiji mdpalaiigj. kijheuiiviib itytocntrmi «rt
Hibeufi(tykcatiiE), tiTMifi(h)it)uu4tiiA) iftfciT]trrsnrt.('vTTitli«r> >it1 [OtaidBS), aaetfS
la^uiKn (CO. 9CX NCX dfii »rlpsfai^BS) tE^gBemsacmOCKNCk mdHZSl. antuSGnpodeisCSDt
NCk fvtcGataBj. ivfixMentfetTOj Ujfevestfcafe. lertnv hijte.* (kuw
\ftHw Rrtgocs' CS M-G phfrrt ?£pmcfcd sriK*. dssrtved r* ji imtirv;! twygancterml(BCCI r*Ji
Inrrpamri) dtnfe ntrnftrt. deuaodpH ct»rr»r;icwyjortcfcmend(OCX} ocnfev tmnas. mikKl i irai nK cii* vi*J *»»*
cm££H3isUfcj*. xiM uftunlinti' r sdufcri *ff*eci(KJHe.iroOre W stpnki sti^?(pferufc nrtrts anlcMi dunes!
pwiA«CTi«aulge(c*orictf
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As tracked by the national 2017 EPA Toxic Release Inventory (TRI) and shown in Figure 3 below, wastes
and chemical releases from petroleum refineries are not equally distributed between environmental
media receptors. The reader should be aware that TRI "pounds released" data presented here is not
equivalent to a "risk" ranking. Weighting each pound of release equally does not factor in the relative
toxicity of each chemical that is released.
Figure 3. 2017 TRI disposal and release data for Industry NAICS 32411 Petroleum Refineries
Figure 4 and the dialogue below breakdown chemicals and the air, water, and soil hazards posed by
refineries:16
• Air pollution hazards: Petroleum refineries are a major source of hazardous and toxic air
pollutants such as BTEX compounds (benzene, toluene, ethylbenzene, and xylene). They are also
a major source of criteria air pollutants: particulate matter (PM), nitrogen oxides (NOx), carbon
monoxide (CO), hydrogen sulfide (H2S), and sulfur dioxide (S02). Refineries also release less
toxic hydrocarbons such as natural gas (methane) and other light volatile fuels and oils. Air
emissions can come from several sources within a petroleum refinery including: equipment
leaks (from valves or other devices); high-temperature combustion processes in the actual
burning of fuels for electricity generation; the heating of steam and process fluids; and the
transfer of products. These pollutants are typically emitted into the environment over the
course of a year through normal emissions, fugitive releases, accidental releases, or plant
upsets. 75% of releases from petroleum refineries are released to the air17.
16 Hazardous Substance Research Center Environmental Update #12 "Environmental impact of the Petroleum
Industry" of June 2003
17 EPA 2017 TRI data
Total Disposal or Other Releases, 2017
69.85 million pounds
On-site Surface Water Disch
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• Water pollution hazards: Refineries are also potential major contributors to ground water and
surface water contamination. Some refineries use deep-injection wells to dispose of wastewater
generated inside the plants, and some of these wastes end up in aquifers and groundwater.
These wastes are then regulated under the Safe Drinking Water Act (SDWA). Wastewater in
refineries may be highly contaminated given the number of sources it can encounter during the
refinery process (such as equipment leaks and spills and the desalting of crude oil). This
contaminated water may be process wastewaters from desalting, water from cooling towers,
stormwater, distillation, or cracking. It may contain oil residuals and many other hazardous
wastes. This water is recycled through many stages during the refining process and goes through
several treatment processes, including a wastewater treatment plant, before being released into
surface waters. The wastes discharged into surface waters are subject to discharge regulations
and are regulated under the CWA. These discharge guidelines generally limit the amounts of
sulfides, ammonia, suspended solids and other compounds that may be present in the
wastewater. Although these guidelines are in place, sometimes significant contamination from
past discharges may remain in surface water bodies. 24% of releases from petroleum refineries
are released to water.
• Soil pollution hazards: Contamination of soils from the refining processes is generally a less
significant problem when compared to contamination of air and water. Past production
practices may have led to spills on refinery property that now need to be cleaned up. Many
residuals are produced during the refining processes, and some of them are recycled through
other stages in the process. Other residuals are collected and disposed of in landfills, or they
may be recovered by other facilities. Soil contamination including some hazardous wastes, spent
catalysts or coke dust, tank bottoms, and sludges from the treatment processes can occur from
leaks as well as accidents or spills on or off site during the transport process. Only one percent
of releases from refineries are released to the land.1819
Of the top ten toxic Toxics Release Inventory (TRI) chemicals most frequently reported by refineries, the
prevalence of volatile chemicals explains the air intensive toxic chemical loading of the refining industry.
Nine of the ten most commonly reported toxic chemicals are highly volatile. Seven of the ten are
aromatic hydrocarbons (benzene, toluene, ethylbenzene, xylene, cyclohexane, 1,2,4-trimethylbenzene
and ethylbenze). Aromatic hydrocarbons are highly volatile compounds and make up a portion of both
crude oil and many finished petroleum products. Ammonia, the ninth most commonly reported toxic
chemical, is also released and transferred from petroleum refineries in large quantities. Ammonia may
be found in high concentrations in process water streams from steam distillation processes and in
refinery sour gas. The primary means of release to the environment is through underground injection of
wastewater and emissions to air. Gasoline blending additives (i.e., methanol, ethanol, and MTBE) and
chemical feedstocks (propylene, ethylene and napthalene) are also commonly reported to TRI. Additives
and chemical feedstocks are, for the most part, released as air emissions due to their high volatility. A
significant portion of the remaining chemicals of the reported TRI toxic chemicals are metals
compounds, which are typically transferred off-site for recovery or as a component of hazardous wastes.
18 EPA OIG report 2004-P-00021 "EPA needs to Improve Tracking of National Petroleum Refinery Compliance
Program Progress and Impacts", June 22, 2004
19 EPA 2017 TRI data for NAICS 324110 Petroleum Refineries
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Although it is not the most frequently reported toxic chemical released or transferred, sulfuric acid is
generated in the largest quantities. Spent sulfuric acid is primarily generated during the alkylation
process. The acid is typically transferred off-site for regeneration.20
NAICS 314110 Petroleum Refineries Total Releases by Chemical and Media
2017 in pounds excerpt
Figure 4 2017 TRI chemical data for Industry NAICS 32411 Petroleum Refineries
Refinery Accidents
Oil spills contaminate soil and water and may cause devastating explosions and fires.21 Refinery
accidents are not generally common but occur more frequently at some sites. The Philadelphia Energy
Solutions (formerly Sunoco) Refinery (also highlighted in the Section B.i of the "Enforcement, Court
Settlements and Judgements in the Petroleum and Coal Products Industry" background document) had
two incidents in a single month22.
The consequences and associated releases can be significant23. For example, petroleum
refineries are more likely to have used Aqueous Film Forming Foam (AFFF) to suppress fire risks. This
material is a major source of Per- and Polyfluoroalkyl Substances (PFAS),24 which can lead to adverse
human health effects25. The U.S. Chemical Safety Board (CSB) conducts root cause investigations of
chemical accidents at fixed industrial facilities. Root causes are usually deficiencies in safety
management systems but can be any factor that would have prevented the accident if that factor had
not occurred. Other accident causes often involve equipment failures, human errors, unforeseen
chemical reactions or other hazards. The CSB agency does not issue fines or citations, but does make
recommendations to plants, regulatory agencies, industry organizations, and labor groups. The CSB
recently investigated the following incidents at refineries:
20 EPA September 1995 49 SIC 2911 Sector Notebook Project Petroleum Refining
21 US Energy Information Administration Oil and the Environment accessed at
https://www.eia.gov/energvexplained/index.php?page=oil environment
22 NBC report of 21 Jun 2019 accessed at https://www.nbcphiladelphia.com/news/local/Massive-Fire-Reports-of-
Explosions-at-South-Philadelphia-Refinerv-Philadelphia-Energy-Solutions-l-76-Closed-511615281.html
23 EPA Mar 1998 Chemical Accident Investigation Report, Pennzoil Product Refinery, 550-R-98-001
24 Interstate Technology & Regulatory Council (ITRC) PFAS Nuts and Bolts Presentation of 14 Aug 2019.
25 EPA Basic Information on PFAS accessed at https://www.epa.gov/pfas/basic-information-pfas
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At the April 26, 2018 Husky Superior Refinery incident, debris from the explosion flew
about 200 feet, and impacted a large, nearby, aboveground storage tank containing about
50,000 barrels of asphalt, puncturing the side of the steel tank and spilling over 15,000 barrels of
hot asphalt into the refinery. This released asphalt ignited about two hours after the explosion,
creating a large fire. The evacuation zone consisted of a 3-mile radius around the refinery, and a 10-
mile rectangle extending south from the refinery. 26 Because of the explosion, thirty-six people
sought medical attention, including eleven refinery and contract workers who suffered OSHA
recordable injuries. In addition, a large portion of Superior Wisconsin was evacuated. The evacuation
zone size was established to protect the public from the smoke plume and as a precaution in case
the refinery's highly toxic hydrofluoric acid equipment was compromised.
On Sunday, November 29, 2015, an operator at the Delaware City Refining Company's
Kellogg Alkylation Unit suffered second degree burns to his face and neck areas while
performing de-inventorying activities on a vessel in preparation for the removal of a pipe spool
from a connected process.27 This fire and explosion incident follows two other incidents at the
same facility which occurred on August 21, and August 28, 2015.
February 18, 2015, fire and explosion in a gasoline processing unit at the ExxonMobil
Refinery in Torrance, CA, led to two workers suffering minor injuries and debris being dispersed
into the surrounding community.28 Because of this incident, a near miss event occurred in the
modified hydrofluoric acid (MHF) alkylation unit when explosion debris nearly hit tanks
containing hydrofluoric acid (HF), water, hydrocarbons, and a chemical additive intended to
reduce the amount of HF vaporized during a loss of containment event. HF is a highly toxic
chemical. In addition, catalyst dust was reported outside of the refinery property in the nearby
community.
A sulfuric acid spill on February 12, 2014, burned two workers in the Tesoro Martinez
refinery's alkylation unit. The two workers were transported to the nearest hospital burn unit.
The CSB investigated29 two separate sulfuric acid release incidents that occurred in February and
March 2014 in the alkylation unit of the Tesoro Martinez refinery in Martinez, California. The
incidents caused acid burn injuries to four workers and two of these workers each missed over
150 days of work. The February incident also caused a significant release of approximately
84,000 pounds of sulfuric acid from a 100,000-gallon vessel containing sulfuric acid and
hydrocarbons.
A fire and explosion on October 23, 2009 at the Caribbean Petroleum Refinery sent huge
flames and smoke plumes into the air at the Caribbean Petroleum Corporation near San Juan,
26 U.S. Chemical Safety and Hazard Investigation Board, Factual Investigation Update of August 2018.
https://www.csb.gov/huskv-energv-refinerv-explosion-and-fire/
27 US Chemical Safety Board Report accessed at httpsi//www.csb.gov/de 1 aware-city-refining-company/
28 US Chemical Safety Board Report accessed at https://www.csb.gov/exxonmobil-refine17-chemical-release-and-
fire/
29 US Chemical Safety Board Report accessed at https://www.csb.gov/tesoromartinez-sulfuric-acid-spill/
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Puerto Rico30. A 5-million gallon aboveground storage tank (AST) overflowed into a secondary
containment dike. The gasoline spray aerosolized, forming a large vapor cloud, which ignited
after reaching an ignition source in the wastewater treatment (WWT) area of the facility. The
blast and fire from multiple secondary explosions resulted in significant damage to 17 of the 48
petroleum storage tanks and other equipment onsite and in neighborhoods and businesses
offsite. The fires burned for almost 60 hours. Petroleum products leaked into the soil, nearby
wetlands and navigable waterways in the surrounding area. At the nearby Fort Buchanan
military facility thousands of gallons of oil, fire suppression foam, and contaminated runoff were
released to the environment.
Industry 32412: Asphalt Paving. Roofing, and Saturated Materials Manufacturing
This industry comprises establishments primarily engaged in (1) manufacturing asphalt and tar paving
mixtures and blocks and roofing cements and coatings from purchased asphaltic materials and/or (2)
saturating purchased mats and felts with asphalt or tar from purchased asphaltic materials.
NAICS 324121: Asphalt Paving Mixture and Block Manufacturing Subsector
This U.S. subsector comprises establishments primarily engaged in manufacturing asphalt and
tar paving mixtures and blocks from purchased asphaltic materials. Asphalt plants, or more accurately
asphalt pavement mixing facilities, are industrial operations that mix liquid asphalt binder (also called
asphalt cement) with crushed rock, gravel, and sand (collectively called aggregates) to make pavement.
Asphalt binder, the glue that binds the aggregates together, is one of many distilled products obtained
from the oil refining process. Like other refined oils, asphalt binder is processed to meet defined
standards. Some mixes also require additives, which can range from chemicals that improve mix
performance to natural fibers that strength specialty mixes.31 Historical practice of using asphalt
admixtures with coal tar was known to contain carcinogenic benzopyrene amongst other polyaromatic
hydrocarbons (PAH).32 This practice is generally no longer used.
In 2002, the EPA officially delisted asphalt plants as a major source of air pollution.33 In 2003 EPA
finalized the National Emission Standards for Hazardous Air Pollutants: Asphalt Processing and Asphalt
Roofing Manufacturing to limit the hazardous air emissions from asphalt processing facilities.34 This rule
reduced toxic air emissions from asphalt processing and roofing manufacturing facilities by about 95
tons per year. The air toxics reduced include numerous organic compounds such as: formaldehyde,
30 US Chemical Safety Board Report accessed at https://www.csb.gov/caribbean-petroleum-refining-tank-
explosion-and-fire/
31 Environmental Impact of Asphalt Plants, National Asphalt Pavement Association, SR 206, May 2015
32 Asphalt Pavements and the Environment, Dr. G. Kennepohl, International Symposium on Asphalt Pavement and
Environment, Aug 2008.
33 EPA (2002). "National Emission Standards for Hazardous Air Pollutants: Revision of Source Category List Under
Section 112 of the Clean Air Act." Federal Register, Vol. 67, No. 29, pp. 6521-6536 accessed at
http://www.gpo.gov/fdsvs/pkg/FR-2002-02-12/pdf/02-3343.pdf
34 40 CFR Part 63 National Emission Standards for Hazardous Air Pollutants: Asphalt Processing and Asphalt Roofing
Manufacturing; Final Rule; accessed at https://www.epa.gov/stationary-sources-air-pollution/asphalt-processing-
and-asphalt-roofing-manufacturing-national
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hexane, phenol, polycyclic organic matter, and toluene. Exposure to these air toxics may cause cancer,
central nervous system problems, liver damage, respiratory problems and skin irritation.
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NAICS 324122: Asphalt Shingle and Coating Materials Manufacturing Subsector
This U.S. industry comprises establishments primarily engaged in saturating purchased mats and
felts with asphalt or tar from purchased asphaltic materials and manufacturing asphalt and tar and
roofing cements and coatings from purchased asphaltic materials. Atypical asphalt shingle consists of
different materials, including a granular/aggregate surface, asphalt, an asphalt-impregnated mat
(commonly composed of a fiberglass or organic felt), and fine mineral base. The base material provides
the matrix to support the other components, while the asphalt provides weather resistance, increases
the stability of the shingle under extreme temperatures, and waterproofing. The granular/aggregate
surface on top protects the asphalt from sun damage and adds a desired color to the product. The
American Society for Testing and Materials (ASTM) has developed specifications for roofing shingles:
ASTM D 225-86 (Asphalt Shingles (Organic Felt) Surfaced with Mineral Granules) and ASTM D3462-87
(Asphalt Shingles Made from Glass Felt and Surfaced with Mineral Granules). Asphalt is a dark brown to
black cement-like semisolid, solid or viscous liquid produced during petroleum refining. Before being
used to make shingles, asphalt must be converted to oxidized asphalt in a process called "blowing",
which bubbles oxygen into the liquid asphalt and increases its viscosity. The process is monitored and
stopped when the desired properties are produced.35
As shown in Figure 5, the manufacture of asphalt shingles consists of six major operations. The
base material passes through a saturator tank filled with hot asphalt. Once coated with the appropriate
thickness of asphalt, one side of the shingle is then surfaced with granules for protection against
physical and sun damage. The granules exposed in the roofing application are comprised of crushed rock
coated with ceramic metal oxides. A light coating of fine sand is applied to the back surface of the
shingle to prevent the individual shingles from adhering to each other during packaging and transport.
The final steps in the production of asphalt shingle are the finish, cutting, and packaging. Asphalt-coated
material from the manufacturing process includes shingle fragments and scrap generated by cutting tabs
on the shingles. In some cases, this material is sold for use in making asphalt pavement for roads.
Because of shipping costs, however, this option may not be practical unless a paving asphalt processing
plant is located relatively close to the shingle plant.
Asbestos in Asphalt Shingles
According to the United States Geological Survey and the Asbestos Information
Association/North America (AIA/NA, an asbestos industry trade group), asbestos is not used in the
production of asphalt shingles today and was phased out as a material used in the production of asphalt
shingles in the early 1980s (USGS 2007; AIA/NA 2007).
There are limited data available regarding the asbestos content previously used in roofing
products, including asphalt shingles. Manufacturer data regarding asbestos content in shingles is sparse.
Johns-Manville Corporation, who began manufacturing asbestos-containing roofing products in the late
1800s, manufactured asbestos-asphalt roofing shingles (further described as asphalt-impregnated
asbestos-fiberglass reinforced shingles) from 1907 to 1979 that contained between 35 and 50%
asbestos. It is noted that this may not necessarily be representative of the amount of asbestos used in
35 Environmental Issues Associated with Asphalt Shingle Recycling, US EPA Innovations Workgroup, Townsend,
Powell & Xu, 19 October 2007.
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the manufacture of asphalt shingles by others, but the data do indicate that the amount of asbestos
used by some manufacturers was significant.
EPA first developed the National Emission Standards for Hazardous Air Pollutants (NESHAP) for
asbestos in 40 CFR Part 61 in April 1973 and it was revised in November 1990.The asbestos NESHAP
defines asbestos containing material (ACM) as any material containing more than 1% asbestos. ACM is
further characterized as either friable (a material that, when dry, can be crumbled, pulverized, or
reduced to powder by hand pressure) or non-friable. NESHAP classifies non-friable ACM as Category I or
Category II. Category I material is defined as asbestos-containing resilient floor covering, asphalt roofing
products, packing and gaskets. The NESHAP specifically identifies several asphalt-containing roofing
products that may also contain asbestos: Built-up roofing, Single ply membrane systems, Asphalt
shingles, Underlayment felts, Roof coatings and mastics, and Base flashings. Lawrence Berkeley National
Laboratory published their Review of Methods for the Manufacture of Residential Roofing Materials in
June 2003.36 EPA also completed detailed reviews in 200137 and 199538 of manufacturing methods and
emissions from asphalt roofing manufacturers.
36 A Review of Methods for the Manufacture of Residential Roofing Materials, Lawrence Berkeley National Lab,
LBNL-55574, June 2003.
37 Asphalt Roofing and Processing Revised Industry Profile, 68-D-99-024, Mar 2001
38 EPA. 1995. Compilation of Air Pollutant Emission Factors, AP-42, Fifth Edition, Volume I: Stationary Point and
Area Sources. Chapter 11. United States Environmental Protection Agency accessed at
httpi//www.epa.gov/ttn/chief/ap42/chll/final/clls02.pdf
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VENT TO
CONTROL
EQUIPMENT
EMISSION SOURCE
see
FELT SATURATION: DIPPING ONLY
3-05-001
03
FELT SATURATION: DIPPING/SPRAYING
3-05-001
04
DIPPING ONLY
3-05-001
11
SPRAYING ONLY
3-05-001
12
DIPPING/SPRAYING
3-05-001
13
DIP SATURATOR, DRYING-IN DRUM, WET LOOPER, AND COATER
3-05-001
16
DIP SATURATOR, DRYING-IN DRUM, AND COATER
3-05-001
17
DIP SATURATOR, DRYING-IN DRUM, AND WET LOOPER
3-05-001
18
SPRAY/DIP SATURATOR, DRYING-IN DRUM, WET LOOPER,
3-05-001
19
COATER, AND STORAGE TANKS
FIXED ROOF ASPHALT STORAGE TANKS
3-05-001
30,
31
FLOATING ROOF ASPHALT STORAGE TANKS
3-05-001
32,
-33
Figure 5. Asphalt Shingle Production Processes39
39 Midwest Research Institute (MRI). 1995. AP-42, 5th Edition, Volume 1, Chapter 11 Mineral Products Industry.
Prepared for U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. Cary, NC:
Midwest Research Institute.
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Industry 32419: Other Petroleum and Coal Products Manufacturing
NAICS 324191: Petroleum Lubricating Oil and Grease Manufacturing Subsector
This U.S. subsector comprises establishments primarily engaged in blending or compounding
refined petroleum to make lubricating oils and greases and/or re-refining used petroleum lubricating
oils. Lubricating (or lube) oils and greases are used to reduce stickiness, keep moving parts separate,
reduce friction, transfer heat, carry away contaminants and debris, transmit power, protect against
wear, prevent corrosion, and create a seal for gasses. They are an essential element in modern
transportation, manufacturing and industry worldwide.
Please note that number of other non-lubricant products are traditionally manufactured and
supplied by global Petroleum Lubricating Oil and Grease Manufacturing companies.40 These products
include corrosion protectives, industrial waxes and process oils, which are supplied either for use as
ingredients to be incorporated into other products, such as rubber extenders or printing ink oils, or for
use by the general manufacturing industry. In the United States around thirty companies produce
lubricant additive chemicals, or packages of additives. These are sold to lube oil blending facilities. A few
large companies both manufacture additives and blend them into oils.41
Lube oil is refined, filtered, and then additives are mixed in. Application based chemical
additives are mixed with the refined oil to give it desired physical properties. Common additives include
metals such as lead or metal sulphide, which enhance lube oil's ability to prevent galling and scoring on
metal surfaces under extremely high pressures. High-molecular weight polymeries are another common
additive: they improve viscosity, keeping oils from thinning at high temperatures. Nitrosamines are
employed as antioxidants and corrosion inhibitors to neutralize acids and form protective films on metal
surfaces.
Greases are used in situations where it is not feasible to provide an oil supply, e.g. in wheel
bearings, constant-velocity joints, steering components, etc. Greases, which are essentially oils plus a
thickening agent, lubricate components by means of the slow release of oil from the grease structure.
Many of the greases used in automotive applications contain additional extreme pressure (EP) agents, as
well as solid lubricants such as molybdenum disulphide. Grease thickening agents include alkali-metal
soaps (normally lithium and calcium) of fatty acids (normally 12-hydroxystearic acid), polymers
(normally polyethylene or polypropylene), diatomaceous earths and a variety of other materials used in
specialized applications. The oil component is normally hydrocarbon-based.
Oil and Grease Processes
Lube oil is extracted from crude oil, which undergoes a preliminary purification process
(sedimentation) before it is pumped into fractionating towers. Atypical high-efficiency fractionating
tower, 25 to 35 feet in diameter and up to 400 feet tall, is constructed of high-grade steels to resist
corrosion. Inside, it is fitted with an ascending series of condensate collecting trays. Within a tower, the
40 OECD Environment Directorate/ Emission Scenario Document on Lubricants and Lubricant Additives/
ENV/JM/MONO(2004)21. 26 Nov 2004, pg 12
41 OECD Environment Directorate/ Emission Scenario Document on Lubricants and Lubricant Additives/
ENV/JM/MONO(2004)21. 26 Nov 2004, pg 13
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thousands of hydrocarbons in crude oil are separated from each other by fractional distillation. As the
vapors rise through the tower, the various fractions cool, condense, and return to liquid form at
different rates determined by their respective boiling points (the lower the boiling point of the fraction,
the higher it rises before condensing). Lubricants have relatively low boiling points compared to natural
gas, gasoline, kerosene, and fuel oil.
Sedimentation
Like a refinery, the oil undergoes sedimentation to remove any water and solid contaminants,
that maybe suspended in it. During this process, the material is pumped into holding tanks, where
contaminants settle out of the oil.
Fractionating
During this stage, the oil is heated to about 700 degrees Fahrenheit. At this temperature the oil
breaks down into a mixture of hot vapor and liquid that is then pumped into the bottom of the first of
two fractionating towers. Here, the hot hydrocarbon vapors float upward. As they cool, they condense
and are collected in different trays installed at different levels in the tower. In this tower, normal
atmospheric pressure is maintained continuously, and about 80 percent of the crude oil vaporizes. The
remaining 20 percent of the oil is then reheated and pumped into a second tower, wherein vacuum
pressure lowers the residual oil's boiling point so that it can be made to vaporize at a lower
temperature. The heavier compounds with higher boiling points, such as tar and the inorganic
compounds, remain behind for further processing.
Filtering and solvent extraction
After further processing to remove unwanted compounds, the lube oil that has been collected in
the two fractionating towers is passed through several ultrafine filters, which remove remaining
impurities. Solvent extraction is used to remove aromatics. When the lube oil is treated with solvent, the
aromatics dissolve; later, after the solvent has been removed, the aromatics can be recovered.
Additives, inspection, and packaging
Finally, the oil is mixed with additives to give it the desired physical properties. At this point, the
lube oil is inspected with a variety of tests42 that assess its viscosity, specific gravity, color, flash, and fire
points. Oil that meets quality standards is then packaged for sale and distribution. Common engine oils
are classified by viscosity according to specifications established by the Society of Automotive Engineers
(SAE).43 Performance factors are classified by the American Petroleum Institute (API), and include wear
prevention, oil sludge deposit formation, and oil thickening.
Oil and Grease Production Emissions and wastes
In December 2004, the international Organisation for Economic Co-operation and Development
completed an Emission Scenario Document44 (ESD) on lubricants used in three areas - automotive
42 Analysis of Petroleum Products & Lubricants, American Society for Testing & Materials, 1991 accessed at
httpsi//www. astm.org/Standards/petroleum-standards. html
43 SAE Viscosity standard accessed at Iittpsi//www.sae.ore/standards/content/i300 201304/
44 OECD Environment Directorate/ Emission Scenario Document on Lubricants and Lubricant Additives/
ENV/JM/MONO(2004)21. 26 Nov 2004
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lubricants, hydraulic fluids and metal working (cutting) fluids. This reference is intended to provide
information generally on the sources, use patterns and release pathways of chemicals used in lubricants
to assist in the estimation of releases of chemicals into the environment.
Emissions to air during the additive process are to be controlled and monitored. Maximum
release levels are prescribed locally and vary depending upon local environmental factors. Parameters
controlled may include hydrogen chloride, volatile organic compounds, particulate matter, total amines
etc. Controls such as wet scrubbing may be required under certain circumstances. Where necessary,
emissions from drummed intermediates are controlled during the emptying process by engineered
systems. In the case of some specialist additives, the equipment generally incorporates vent condensers
to control reactions not only for environmental protection but also to maximize yields.
To eliminate any environmental impact to water from accidental spills, blend drainage systems
are separated from any domestic drains. The blend drains, where appropriate, are generally connected
to the chemical plant system and have appropriate abatement equipment such as skimmers or effluent
treatment plant. The final discharge from this process is into controlled waters and is maintained within
locally prescribed limits, which may, where appropriate, include biological oxygen demand, suspended
solids, hydrocarbon oil, pH, temperature etc. There is no use of water in the additive blending process.
Losses from the blending process can be kept to a minimum through careful housekeeping and planning.
The mixing vessels are rinsed with oil to remove residual additives and the oil recycled. By sequencing
the composition of batches carefully the residues can be used in the following product. These factors in
combination with the controls on such processes mean that emissions are expected to be negligible.
Lubricant and grease blending plants have atmospheric emissions of volatile organic compounds
(VOCs) that are extremely low because of the generally involatile nature of lubricants and their
associated additives. The oil contents of aqueous waste from lubricant plants are normally controlled
within specified or permitted limits and tracked with monitoring records. Fluid effluents are also
monitored externally as appropriate and required by the relevant discharge entity. Due to the
comparatively high viscosity of most lubricants, accidental spills are normally readily contained. Overall,
losses to the atmosphere are expected to arise only from pre-heating and blending and to be very low.
In general releases of lube oils and greases as more extensive during use than in manufacturing.
NAICS 324199: All Other Petroleum and Coal Products Manufacturing Subsector
This U.S. subsector comprises establishments primarily engaged in manufacturing petroleum
products (except asphalt paving, roofing, and saturated materials and lubricating oils and greases) from
refined petroleum and coal products made in coke ovens not integrated with a steel mill. Coal is used in
the production of metallurgical coke as blast furnace fuel. Some smaller blast furnaces can use charcoal
as a carbon source, but the larger blast furnaces require coke. Coke used in blast furnaces converts iron
ore to iron, which can be further refined to produce steel.
There are three proven processes for the manufacture of metallurgical coke: the byproduct
process, the heat recovery process and the beehive process. The heat recovery process is a modification
of the beehive process. The beehive process has been largely phased out.
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Coke is produced in the byproduct process by igniting bituminous coal under reduced oxygen
conditions in oven batteries specially designed for this process. A battery consists of a group of ovens
connected by common walls.45 In the coke oven, the coal is heated to 1,800°F for up to 18 hours. During
that time, the volatiles of the coal are driven off and a pure carbon form called "coke" remains. This
process generates the following main volatiles as byproducts: coke oven gas, tar, ammonium sulfate,
benzol, toluol and naphtha.46 Further details on this process are available in Section 12.2.1 of the May
2008 EPA review of the Metallurgical Industry.47 "Coke oven emissions are among the most toxic of all
air pollutants. Emissions from coke ovens include a mixture of polycyclic organic matter, benzene, and
other chemicals that can cause cancer. Occupational exposure studies of coke oven workers have shown
statistically significant excess mortality from cancers of the respiratory tract, kidney, and prostate and all
cancer sites combined".48 When the coke is pushed from the oven into a railcar, it is quickly quenched to
cool the coke and stop the burning process.49
According to the American Coke and Coal Chemicals Institute (ACCCI) 2016 listing of US &
Canadian Coke Plants50, there are only 10 US independently owned/operated "merchant" byproduct
coke plants and five heat recovery coke plants. The remaining coke plants are owned/operated by an
integrated steel company with the associated NAICS classifications falling out of this review. For the
purposes of this review, coke production facilities are that are primarily for the direct purpose of
integrated steel manufacturing are not included, as they are not within the NAICS 324 industry
classification.
From an environmental viewpoint, the heat-recovery (aka by-product recovery) technology has
a smaller footprint than the byproduct technology. Due to its negative-pressure operation and
incineration of all the volatile matter in the coal, the heat-recovery process is less susceptible to toxic
gas releases. The coal bed configuration also means particulate emissions are reduced. This process has
some technologies that can improve upon the standard design, such as individual oven pressure control
and coke stabilization quenching, which can minimize particulate and toxic emissions.51 Emissions from
a heat recovery plant are primarily organic vapors such as benzene and other light aromatics, POM,
cyanides, phenols, and light oils. These emissions occur from the separation processes, process vents,
and transfer operations for recovered intermediates or products. These emissions also occur from
wastewater that has contacted either the coke-oven gas or is generated from separation processes
45 EPA rule 40 CFR Part 63 Subpart CCCCC accessed at https://www,epa,gov/stationary-sources-air-pollution/coke-
ovens-pushing-quenching-and-battery-stacks-national-emission
46 International Agency for Research on Cancer, Chemical Agents and Related Occupations, Coke Production
accessed at https://www.ncbi.nlm.nih.gov/books/NBK304422/
47 EPA Metallurgical Industry AP 42 Section 12-2 of May 2008 accessed at
https://www3.epa.gov/ttn/chief/ap42/chl2/final/cl2s02 may08.pdf
48 EPA NESHAP for Coke Ovens accessed at https://www.epa.gov/sites/production/files/2016-
01/documents/cokefact.pdf
49 Association for Iron & Steel Technology's (AIST) Interactive Steel Manufacturing Process
The Making, Shaping & Treating of Steel Wheel accessed at
https://monvallev.uss.com/uss/portal/monvallev/monvallevworks/cokemakingprocess/
50 Operating U. S. Coke Plants List, Feb 2016, littp://accci.org/docymejits/CokePlantListing 080316.pdf
51 Towsey, Cameron, and Gordon. Comparison of Byproduct and Heat-Recovery Cokemaking Technologies. Iron
and Steel Technology, Mar 2011, http://www.accci.org/documents/CokemakingTechnologies Comparison.pdf
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when the water is handled in open wastewater treatment systems. Although not a criteria pollutant or
HAP, ammonia (a particulate precursor) also is emitted from the excess ammonium liquor tank, tar
decanter, and flushing liquor tank. Many plants control these emissions using gas blanketing or vapor
balance/recovery techniques that collect the organic vapors and contain them within the gas handling
system where they are eventually recovered. Further details on this process are available in the May
2008 EPA review of the Metallurgical Industry52 and the EPA Environmental Assessment of Coke
Byproduct Recovery Plants.53
52 EPA Metallurgical Industry 12-2-53 of May 2008 accessed at
httpsi//www3.epa.gov/ttn/chief/ap42/chl2/final/cl2s02 mav08.pdf
53 Environmental Assessment of Coke Byproduct Recovery Plants. EPA-600/2-79-016, U. S.
Environmental Protection Agency, Research Triangle Park, NC, January 1979.
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