Materials Characterization Paper

In Support of the

Advanced Notice of Proposed Rulemaking –

Identification of Nonhazardous Materials That Are Solid Waste

Used Oil

December 16, 2008

========================================================

1.	Definition of Used Oil 

EPA defines used oil as any oil that has been refined from crude oil, or
any synthetic oil, that has been used and as a result of such use is
contaminated by physical or chemical impurities.  

EPA’s criteria for used oil:

Origin: Used oil must have been refined from crude oil or made from
synthetic materials (i.e., derived from coal, shale, or polymers). 
Examples of crude-oil derived oils and synthetic oils are motor oil,
mineral oil, laminating surface agents, and metal working oils.  Thus,
animal and vegetable oils are not included.  Bottom clean-out from
virgin fuel oil storage tanks or virgin oil recovered from a spill, as
well as products solely used as cleaning agents or for their solvent
properties, and certain petroleum-derived products such as antifreeze
and kerosene are also not included.

Use:  The oil must have been used as a lubricant, coolant, heat
(non-contact) transfer fluid, hydraulic fluid, heat transfer fluid or
for a similar use.  Lubricants include, but are not limited to, used
motor oil, metal working lubricants, and emulsions.  An example of a
hydraulic fluid is transmission fluid.  Heat transfer fluids can be
materials such as coolants, heating media, refrigeration oils, and
electrical insulation oils.  Authorized states or regions determine what
is considered a “similar use” on a site-specific basis according to
whether the material is used and managed in a manner consistent with
Part 279 (e.g., used as a buoyant). 

Contaminants:  The used oil must be contaminated by physical (e.g., high
water content, metal shavings, or dirt) or chemical (e.g., lead,
halogens, solvents or other hazardous constituents) impurities as a
result of use. 

Annual Quantities of Used Oil Generated and Used

Sectors that Generate Used Oil:    

According to EPA, generators of used oil include “businesses that
handle used oil through commercial or industrial operations or from the
maintenance of vehicles and equipment.” Examples include:

Automotive repair shops

Vehicle service stations

Fleets

Grocery stores 

Metal working industries

Energy industry

Boat marinas (EPA 2008b)

Exhibit 1 lists the NAICS codes of the major sectors that generate used
oil.

Exhibit 1:  NAICS Codes for Used Oil Generators

NAICS	NAICS Title



1111	Crop production

2212	Electric services

2212	Electric and other services combined

3242	Petroleum and coal products

332, 3332	Special industry machinery

3331	Metal working industries

333, 3362	Construction machinery and equipment

4212	Scrap and waste materials

4451	Grocery stores 

484, 488, 492, 493, 5622	Motor freight transportation and warehousing

7131	Boat marinas 

8111	Automotive repair shops

8111	Fleets

8111	Vehicle service stations

8141	Private households

5621	Waste Management and Remediation Services



Sources:

Description of sectors from EPA 2008b; NAICS identified from U.S. Census
Bureau 2007.

EPA 2005b.



Quantities of Used Oil Generated:   

Exhibit 2 summarizes the annual generation and management of used oil. 
As indicated in the exhibit, an estimated 70 percent of used oil is
either used as a fuel (i.e., burned for energy recovery) or re-refined
into lubricating oil. However, depending upon the year, estimates
indicate that as much as 90 percent of all collected used oil is burned
for energy recovery, leaving 10 percent or less to be re-refined into
lubricating oil (Svizzero 2008).

Trends in Generation:  

The data sources consulted for this document do not include information
on the trend in the generation of used oil.  A 2006 report from the
Department of Energy indicates, however, that the volume of oil changed
by consumers themselves (e.g., households and owners/operators of
commercial vehicles) declined from 60 percent of total oil changes in
1997 to 45 percent in 2005 (DOE 2006, p. 5-2).   This shift in practice
may have helped increase the recycling rate for used oil.  During the
1997-2005 period, the recycling rate for used oil generated by service
stations increased from 66 percent in 1997 to almost 100 percent (DOE
2006, p. 5-2).  

Exhibit 2:  Overview of Annual Generation and Use

Commodity	Annual Quantity Generated	Annual Quantity 

Used as Fuel	Annual Quantity Disposed of in Landfills or Improper
Locations	Annual Quantity Re-refined	Total Quantity Stockpiled 

Used Oil	1.35 billion gallons	784.4 million gallons	200 million gallons
160.7 million gallons	unknown



Sources:

Unless otherwise noted, data are from the Utah Department of
Environmental Quality 2008a and 2008b and United States Department of
Energy 2006, p.1-4.  These sources include annual generation and
management estimates, but do not specify the year.



Uses of Used Oil

Combustion Uses:  

Use as feedstock at petroleum refinery 

Use as an alternative fuel (EPA 2008b)

For the purposes of regulating used oil burned for energy recovery, EPA
makes a distinction between on-spec used oil and off-spec used oil based
upon a finding that only certain contaminants in used oil pose a
significant threat to human health or the environment.  As a result, EPA
has established maximum concentration limits for these constituents of
concern, as summarized in Exhibit 3.  If the used oil is shown not to
exceed any allowable level, it is on-spec and can be burned in any
combustion device.  Otherwise, it is considered off-specification.  

National information on the distribution between on-spec and off-spec
used oil was not readily available, but we were able to identify this
information for used oil generated in Florida.  In 2005, an estimated
110,308,107 gallons of used oil and oily waste were managed in Florida. 
Of this, 56,569,512 gallons (51.3 percent) were recycled as follows:

41,386,124 gallons (73.2 percent) were marketed as an on-spec used oil
fuel

1,775,815 gallons (3.1 percent) were burned as an off-spec used oil fuel

13,407,573 gallons (23.7 percent) were marketed for other industrial
uses (e.g. phosphate beneficiation) (FL DEP 2006)

Based on the above, we would assume that approximately 73 percent of the
used oil generated and used each year is on-spec.

Exhibit 3:  Criteria for On-Specification Used Oil

Property	Allowable Level

Arsenic	5 ppm maximum

Cadmium	2 ppm maximum

Chromium	10 ppm maximum

Lead	100 ppm maximum

Total Halogens	4,000 ppm maximum1

Flashpoint 	100° F minimum



Source:

EPA 2001

Notes:

1. Used oil containing more than 1,000 ppm total halogens is presumed to
be a hazardous waste under the rebuttable presumption provided under
§279.10(b)(1).  Such used oil is subject to subpart H of part 266
rather than part 279 when burned for energy recovery unless the
presumption of mixing can be successfully rebutted.



As shown in Exhibit 4, asphalt plants are the largest users of used oil
as fuel, followed by space heaters and industrial boilers. It is likely
that asphalt plants use on-spec used oil adhering to the criteria noted
in Exhibit 3 above. 

Exhibit 4:  Users of Used Oil 

(DOE 2006, p. 5-2)

Non-Combustion Used Oil Uses:  Used oil may be re-used if it is
processed or regenerated (EPA 2008b).

Quantities of Used Oil Landfilled:  Approximately 200 millions gallons
of used oil are landfilled or improperly disposed annually (Utah
Department of Environmental Quality 2008a). 

Quantities of Used Oil Stockpiled/stored: Readily available data sources
on used oil do not suggest that this material is stockpiled or stored
(for long periods of time) in large quantities. This is because its
value as a fuel or product leads to its prompt use. 

Management and Combustion Processes for Used Oil

Types of Units Combusting Used Oil:

Facilities burn both on-specification and off-specification used oil. 
However, off-spec used oil may only be burned in specified combustion
devices (EPA 2008):

Industrial furnaces as defined in 40 Code of Federal Regulation (CFR)
§260.10 and §279.61(a).  Industrial boilers as defined in 40 CFR
§260.20 that are located at facilities that are engaged in a
manufacturing process where substances are transformed into new
products.

Utility boilers as defined in 40 CFR §260.20 that are used to produce
electric power, steam, heated or cooled air, or other gases or fluids
for sale. 

Used oil-fired space heaters provided that the burner meets the
provisions of 40 CFR §279.23.

Hazardous waste incinerators subject to regulation under 40 CFR parts
264 and 265, subpart O.

Supply/Processing Chain for Used Oil:  

The Standards for the Management of Used Oil in the Code of Federal
Regulations define processing as “chemical or physical operations
designed to produce from used oil, or to make used oil more amenable for
production of, fuel oils, lubricants, or other used oil-derived product.
Processing includes, but is not limited to: blending used oil with
virgin petroleum products, blending used oils to meet the fuel
specification, filtration, simple distillation, chemical or physical
separation and re-refining” (40 CFR 279.50(a)).

Processing Used Oil for Fuel Applications:  

Used oil is generated from many different sources and then consolidated
at key collection points (e.g., commercial and industrial operations,
automotive repair shops, branch collection networks, and fleets) through
well-established channels before being shipped to processing facilities
and end users.  Based on communications with used oil recyclers and
marketers, the steps to process used oil for use as a fuel are as
follows:

Test the oil to determine whether it’s on-spec or off-spec.  The
recyclers and marketers who we contacted indicated that nearly all used
oil is on-spec; 

Using solvents, remove as much water (and sometimes antifreeze) from the
oil as possible; 

Filter out metal scraps and other larger particles using screens. The
filtering can be done when the oil is collected, or in the burner when
the oil is added (Saunders 2008 and Blackburn 2008). 

The filtering and water extraction processes described above are
standard practice in the industry.  That is, most used oil goes through
these processing steps prior to being used as a fuel (Saunders 2008 and
Blackburn 2008).

In addition to the processing steps outlined above, processors often
store used oil in tanks, allowing oil to separate from other liquids and
settle to the bottom of the tank.  This allows processors to provide
their customers with relatively high-quality used oils (Saunders 2008
and Blackburn 2008).   

Estimated counts of the entities involved in the various stages of used
oil processing and use include the following:

379 used oil transporters and transfer facilities

150 used oil processors and re-refiners

750 burners of off-specification used oil

340 used oil fuel marketers (Office of Management and Budget 2005, p.
52)

  

State Status of Used Oil use as Fuel:  

Based on a review of information from the 2006 Beneficial Use Survey
conducted by the Association of State and Territorial Solid Waste
Management Officials (ASTSWMO), none of the 34 states responding to the
survey reported that they had given used oil a beneficial use
designation as a fuel (ASTSWMO 2007, p.B-38-39).     States typically
regulate used oil practices under federal used oil management standards
(EPA 2008c). This may include establishing programs to encourage
appropriate use of used oil.  For example, DOE indicates that 24 states
have enacted purchasing program preferences to stimulate the demand for
used oil (DOE 6-3 to 6-4).

Used Oil Composition and Impacts

Composition of Used Oil

140,000 Btu per gallon (EPA 2008b)

A 2003 study by Dominguez-Rosado and Pichtel indicates that used motor
oil has the following metals concentrations:

Zinc: 838 mg/kg

Lead: 110 mg/kg

Cadmium: 9.4 mg/kg

Barium: 4,100 mg/kg

Chromium: Not detected (Dominguez-Rosada and Pichtel 2003)

Used oil often contains approximately 2 to 5 percent additives (DOE
2006, p. 9-14).  Exhibit 5 summarizes the most common of these
additives.  In addition to these additives, used oil may include a
number of physical and chemical contaminants, including metals, dirt,
and solvents (EPA, 2008a). 

Exhibit 5:  Common Additives Found in Used Oil 

Purpose of Additive	Additives

Anticorrosion 	Zinc dithiophosphates, metal phenolates, fatty acids and
amines

Antifoamant 	Silicone polymers, organic copolymers

Antiodorant	Perfumes, essential oils

Antioxidant 	Zinc dithiophosphates, hindered phenols. Aromatic amines,
sulphurized phenols

Antiwear Additive	Chlorinated waxes, alkyl phosphites and phosphates,
lead napthenate, metal triborates, metal and ashless dithiophosphates

Color Stabilizer	Aromatic amine compounds

Corrosion Inhibitor	Metal dithiophosphates, metal dithicarbamates, metal
sulfonates, thiadiazoles, and sulfurized terpenes

Detergent	Alkyl sulfonates, phosphonates, alkyl phenates, alkyl
phenolates, alkyl carboxylates, and alkyl substituted salicylates

Dispersant 	Alkylsuccinimides, alkylsuccinic esters

Emulsifier	Fatty acids, fatty amides, and fatty alcohols

Extreme Pressure Additives	Alkyl sulfides, polysulfides, sulfurized
fatty oils, alkyl phosphites and phosphates, metal and ashless
dithiophosphates and carboxylates, metal dithiocarbamates, and metal
triborates

Friction Modifier 	Organic fatty acids. Lard oil. Phosphorous based
compounds

Metal Deactivator	Metal Deactivator Organic complexes containing
nitrogen and sulfur amines, sulphides and phosphates

Pour point depressant 	Alkylated naphthalene and phenolic polymers,
polymethacrylates

Rust Inhibitor	Metal alkylsulfonates, alkylamines, alkyl amine
phosphates, alkenylsuccinic acids, fatty acids, alkylphenol ethoxylates,
and acid phosphate esters

Seal Swell Agent Organic 	Organic phosphates aromatic hydrocarbons

Tackiness Agent	Polyacrylates and polybutenes

Viscosity 	Polymers of olefins, methacrylates, di-enes or alkylated
styrenes



Sources:

DOE 2006, Table 9 and EPA 2005a, Appendix C-2.



Impact Information

Cost Impacts: The cost impact associated with consuming used oil as a
fuel depends on both the value of the fuel that it displaces and the
cost of processing used oil.  The Department of Energy reports that the
market value of used oil is approximately 65 to 75 percent of the price
of No. 6 fuel oil (DOE 2006, p. 4-4), but it is unclear whether this
estimate applies to processed or unprocessed used oil.  At October 2008
fuel prices, the 65 to 75 percent estimate suggests that the value of
used oil is approximately $1.14 to $1.31 per gallon.  In addition, in
terms of the economic benefit realized by facilities that sell their
used oil, a used oil recycler in Idaho indicates that the price paid by
oil recyclers for unprocessed used oil varies depending on the quantity
and frequency of sale (Blackburn 2008).  At current oil prices, used oil
recyclers pay between $0.60 and $1.07 per gallon for used oil (Blackburn
2008).  

Emissions Impacts of Used Oil as a Fuel: To characterize the potential
environmental impacts and benefits associated with the use of used oil
as an alternative fuel, we identified comparative emissions information
for used oil and for the fuels it typically replaces:  distillate fuel
oil and residual fuel oil.  More specifically, we obtained information
on the emissions associated with the combustion of each of these fuels
and the emissions associated with cradle-to-gate processing of the
virgin fuel oil, impacts that would be avoided by burning used oil as an
alternative.  Exhibit 6 below summarizes this information.  Note that
this analysis does not include the emissions associated with the
preparation of used oil for combustion, and may therefore overstate the
relative air emissions reductions associated with using this alternative
fuel.  However, the majority of the upstream impacts of used oil are the
result of the generation of the primary product associated with the oil;
the processing required to prepare used oil for combustion is limited. 
Additionally, since not all contaminants in used oil cause health or
environmental risk, maximum concentration limits can be set such that
used oil burned with concentrations at or below the limits will not
create risk. These concentration limits define the difference between
on-spec and off-spec used oil. 

Exhibit 6 shows that the principal benefits of combustion of used oil
are associated with upstream production offsets and include substantial
reductions of NOx, and CO emissions.  In terms of combustion-specific
emissions, use of used oil results in notably lower NOx emissions, in
particular when compared to residual fuel oil. On the other hand,
particulate matter and lead emissions may be substantially higher than
virgin fuel oil, depending on the concentrations of those compounds in
the used oil.

Note that other uses for used oil may be environmentally preferable to
combustion (e.g., recovery and reuse as a lubricant) but this analysis
examines only combustion uses.

Exhibit 6:  Emission Factors for Used Oil and Alternatives

Pollutant	Used Oil	Distillate Fuel Oil	Residual Fuel Oil

	Combustion	Combustion	Combustion plus Upstream	Combustion	Combustion
plus Upstream

	-------------------------------- Lb./MMBtu ---------------------------

Criteria Pollutants

PM2.5	-	-	-	-	-

PM10	0.162 – 0.190	0.011	0.011	0.093	0.093

PM, unspecified	0.203 – 0.238	-	0.012	-	0.012

NOx	0.131	0.173	0.234	0.367	0.428

VOCs	-	0.001	0.363	0.002	0.367

SOx	0.051 – 1.014	0.209	0.394	1.593	1.781

CO	0.034	0.036	0.082	0.033	0.079

Pb	1.79x10-3 – 2.16x10-3	4.60x10-6	5.61x10-6	5.80x10-5	5.90x10-5

Hg	-	1.58x10-6	1.77x10-6	8.67x10-6	8.85x10-6





Sources:

Distillate fuel oil and residual fuel oil emissions from Franklin
Associates 1998.

Used oil emissions from EPA 1995, Vermont Agency of Natural Resources
1996, 

and Colorado Department of Public Health and Environment.

Notes:

“-” signifies data not available; may equal zero. Heating value of
used oil assumed to be 145 MMBtu/1000 gal.

The emission information presented in this table is derived from Life
Cycle Inventory (LCI) data, as compiled by Franklin Associates.   LCI
data identifies and quantifies resource inputs, energy requirements, and
releases to the air, water, and land for each step in the manufacture of
a product or process, from the extraction of the raw materials to
ultimate disposal. The LCI can be used to identify those system
components or life cycle steps that are the main contributors to
environmental burdens such as energy use, solid waste, and atmospheric
and waterborne emissions.  Uncertainty in an LCI is due to the
cumulative effects of input uncertainties and data variability.  

There are several life cycle inventory databases available in the U.S.
and Europe.  For this paper, we applied the most readily available LCI
database that was most consistent with the materials and uses examined.
These LCI data rely on system boundaries as defined by Franklin
Associates, as described in the documentation for this database,
available at:   HYPERLINK
"http://www.pre.nl/download/manuals/DatabaseManualFranklinUS98.pdf" 
http://www.pre.nl/download/manuals/DatabaseManualFranklinUS98.pdf .  





References

40 CFR 279.50(a)

Association of State and Territorial Solid Waste Management Officials
(ASTSWMO). 2007, 2006 Beneficial Use Study Report, November 2007.

Blackburn, Randy.  2008.  Commercial Fuel Recycling, LLC, Idaho,
personal communication, September 25, 2008 and November 20, 2008. 

Colorado Department of Public Health and Environment.  2008, “A Guide
to Hazardous Waste and Air Requirements for Used Oil Space Heaters”,
accessed on August 29, 2008 at http://  HYPERLINK
"http://www.cdphe.state.co.us/ap/sbap/sbap_useoilheaters.pdf" 
www.cdphe.state.co.us/ap/sbap/sbap_useoilheaters.pdf .

Dominguez-Rosado, Elena and John Pichtel.  2003, “Chemical
Characterization of Fresh, Used, and Weathered 

Motor Oil Via GC/MS, NMR, and FTIR Techniques,” Proceedings of the
Indiana Academy of Sciences, Vol. 12, No. 2, 2003, pages 109-116.

Florida Department of Environmental Protection.  2006,  “Florida’s
Used Oil Recycling Program: 21st Annual 

Report,” March 2006.

Franklin Associates.  1998, “Franklin US LCI 98 Library”.

Saunders, Brandon.  2008.  Polar Refrigerant Technologies, New
Hampshire, personal communication, September 25, 2008.

Svizzero, Michael. 2008. U.S. Environmental Protection Agency, personal
communication, citing American Petroleum Institute data, October 22,
2008. 

United States Census Bureau.  2007.  “2007 NAICS Definitions”.

United States Department of Energy (DOE).  2006, “Used Oil Re-refining
Study to Address Energy Policy Act of 2005 Section 1838”.

United Stated Department of Energy (DOE).  2008, “Short-Term Energy
Outlook,” November 12, 2008.

United States Environmental Protection Agency (EPA). 1995, “AP-42,
Fifth Edition, Compilation of Air Pollutant 

Emission Factors, Volume 1: Stationary Point and Area Sources”. 

United States Environmental Protection Agency (EPA). 2001, “RCRA,
Superfund & EPCRA Call Center Training 

Module Introduction to Used Oil,” October 2001.

United States Environmental Protection Agency (EPA). 2005a, “Guidance
and Summary of Information Regarding 

the RCRA Used Oil Rebuttal Assumption,” March 2005.

United States Environmental Protection Agency (EPA). 2005b,
“Supporting Statement for Information Collection 

Request Number 1286.07 Used Oil Management Standards Recordkeeping and
Reporting Requirements,” November 10, 2005.

United States Environmental Protection Agency (EPA).  2008a, “Code of
Federal Regulations: Standards for the Management of Used Oil”,
accessed August 28, 2008 at   HYPERLINK
"http://www.gpoaccess.gov/index.html" 
http://www.gpoaccess.gov/index.html .

United States Environmental Protection Agency (EPA).  2008b, “Managing
Used Oil: Advice for Small Businesses”, accessed August 19, 2008 at  
HYPERLINK "http://www.epa.gov/epaoswer/hazwaste/usedoil/usedoil.htm" 
http://www.epa.gov/epaoswer/hazwaste/usedoil/usedoil.htm .

United States Environmental Protection Agency (EPA).  2008c,
“Authorization Status by Rule”, accessed December 2, 2008 at
http://www.epa.gov/epawaste/laws-regs/state/stats/authall.pdf.

United States Office of Management and Budget (OMB).  2005,
“Supporting Statement for Information Collection Request Number
1286.07 Used Oil Management Standards Recordkeeping and Reporting
Requirements”.  

Utah Department of Environmental Quality.  2008a, “Used Oil
Section”, accessed on August 28, 2008 at   HYPERLINK
"http://www.usedoil.utah.gov/"  http://www.usedoil.utah.gov/ .

Utah Department of Environmental Quality.  2008b, “Used Oil
Statistics”, accessed on August 28, 2008 at   HYPERLINK
"http://www.usedoil.utah.gov/UsedOilStatistics.htm" 
http://www.usedoil.utah.gov/UsedOilStatistics.htm .

Vermont Agency of Natural Resources.  1996, “Vermont Used Oil Analysis
and Waste Oil Furnace Emissions Study”, accessed on August 29, 2008 at
http://www.epa.gov/ttn/catc/dir1/w_oilacr.pdf.

 See 40 CRF 279.1 for the specific definition.

 EPA’s regulatory definition of used oil generators does not include
1) farmers who produce less than an average of 25 gallons of used oil
per month and 2) individuals who generate used oil through the
maintenance of their personal vehicles and equipment.  Although EPA’s
regulatory definition does not include these groups, the data included
in this document reflect used oil generated by all entities that
generate this material.

 The limits are set such that the emissions resulting from the burning
of used oil containing these contaminants, at or below established
“on-spec” limits, will pose no more threat to human health or the
environment than the emissions resulting from the burning of virgin oil
or diesel (68 FR 44662, July 30, 2003).

 The data source for this estimate does not specify the year represented
by this estimate. 

 As of September 30 2008, 31 states have received federal authorization
for the Recycled Used Oil Management Standards and an additional 10
states have adopted the Standards. 

 The heat input of used oil on a Btu per pound basis depends on the
density of the used oil.  Assuming a density of 7.88 pounds per gallon
(consistent with the density of No. 6 fuel oil), the 140,000 Btu per
gallon estimates translates to 17,766 Btu per pound.

 This is based on a price of $1.75 per gallon for No. 6 fuel oil (DOE
2008).

Used Oil

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