Technical Support Document for the Phosphoric
Acid Production Sector: Proposed Rule for
Mandatory Reporting of Greenhouse Gases
Office of Air and Radiation
U.S. Environmental Protection Agency
February 20, 2009
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
CONTENTS
1. Industry Description 1
2. Total Emissions 1
2.1 Process Emissions 2
2.2 Stationary Combustion 2
3. Review of Existing Programs and Methodologies 2
4. Options for Reporting Threshold 3
4.1 Emissions Thresholds 3
4.2 Capacity Thresholds 3
4.3 No Emissions Threshold 3
4. 4 Analysis of Emissions and Facilities Covered Per Threshold Option 3
4.4.1 Emissions Thresholds 3
4.4.2 Capacity Threshold 5
4.4.3 No Emissions Threshold 5
5. Options for Monitoring Methods 5
5.1 Option 1: Simplified Emission Calculations 5
5.2 Option 2: Hybrid Method 6
5.3 Option 3: Direct Measurement using Continuous Emission Monitoring Data
(CEMS) 7
6. Procedures for Estimating Missing Data 7
6.1 Procedures for Option 1: Simplified Emissions Calculations 7
6.2 Procedures for Option 2: Hybrid Method 7
6.3 Procedures for Option 3: Direct Measurement using CEMS 8
7. QA/QC Requirements 8
7.1 Stationary Emissions 8
7.2 Process Emissions 8
7.3 Data Management 9
8. Types of Emissions to be Reported 9
8.1 Other Information to be Reported 10
8.2 Additional Data to be Retained Onsite 10
9. References 11
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
1. Industry Description
Phosphoric acid is a chemical product derived from phosphate rock and is integral to the
production of phosphate fertilizers. Four states mine phosphate rock (Florida, North Carolina,
Idaho, and Utah) and facilities that produce phosphoric acid are generally located near phosphate
rock mines. Of the 14 phosphoric acid facilities operating in 2006, only 3, located along the Gulf
Coast, consumed phosphate rock imported from Morocco (USGS 2007). Phosphoric acid
production in 2006 at each of the 14 facilities is presented in Table 1.
Table 1. U.S. Producers of Phosphoric Acid
Company
Agrifos, LLC
Agrium
CF Industries
Mississippi Phosphates
Mosaic Fertilizer
Mosaic Fertilizer
Mosaic Fertilizer
Mosaic Fertilizer
Mosaic Fertilizer
PCS Nitrogen
PCS Phosphate Co., Inc.
PCS Phosphate Co., Inc.
J.R. Simplot Co.
J.R. Simplot Co.
Plant Location
Pasadena, TX
Conda, ID
Plant City, FL
Pascagoula, MS
Bartow, FL
Riverview, FL
New Wales, FL
South Pierce, FL
Uncle Sam, LA
Geismar, LA
Aurora, NC
White Springs, FL
Rock Springs, WY
Pocatello, ID
2006 Production (metric tons)
NA
362,000
915,000
NA
893,000
733,000
1,674,000
432,000
547,000
147,000
1,080,000
881,000
NA
NA
Companies marked "NA" are privately-
Source: Personal Communication with
held and do not release financial information.
Stephen Jasinski, USGS.
Phosphoric acid is a product of the reaction between phosphate rock and, typically, sulfuric acid
(H^SO/t). A byproduct called calcium sulfate (CaSO/t), or gypsum, is formed when calcium from
the phosphate rock reacts with sulfate. Most companies in the United States use a dihydrate
process in which two molecules of water (H2O) are produced per molecule of gypsum (CaSC>4 • 2
H^O or calcium sulfate dihydrate). Additionally, a second reaction occurs in which the
limestone (CaCOs) present in the phosphate rock reacts with sulfuric acid (H^SC^) releasing
carbon dioxide (CO2). The amount of carbon in the phosphate rock feedstock varies depending
on the region in which it was mined. Phosphate rock is also used to produce triple super
phosphate and elemental phosphorus.
2.
Total Emissions
Combined, the 14 phosphoric acid plants in operation in 2006 emitted 3.8 MMTCC^e. Process
emissions from phosphoric acid production in 2006 totaled 1.17 tons CC>2 (U.S. EPA 2008).
Combustion emissions (CO2, CH4, and N2O) in 2006 totaled -2.67 MMTCO2e.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
2.1 Process Emissions
Greenhouse gas emissions are generated from both the actual phosphoric production process.
Phosphoric acid is produced by combining sulfuric acid and phosphate rock using a method
known as "wet process production." The chemical reactions that take place to produce
phosphoric acid are shown below (U.S. EPA 2008).
Ca3(PO4)2 + 4H3PO4 -> 3Ca(H2PO4)2
3Ca(H2PO4)2 + 3H2SO4 + 6H2O -> 3CaSO4 • 6H2O + 6H3PO4
A portion of the phosphoric acid produced is recycled to the reactor to sustain the reaction and
ensure that an insoluble layer of calcium sulfate does not enclose the phosphate rock and inhibit
interaction with sulfuric acid (EFMA 2000). Carbon dioxide (CO2) is emitted when the limestone
component (CaCO3) of phosphate rock reacts with the sulfuric acid (H2SO4) (U.S. EPA 2008).
The following reaction summarizes the emission process:
CaCO3 + H2SO4 + H2O -> CaSO4 • 2H2O + CO2
2.2 Stationary Combustion
Combustion-related greenhouse gas emissions from the production of phosphoric acid are
limited to those from burning of fuel inputs used for equipment necessary to the manufacturing
process. Auxiliary and packaged boilers are common combustion emission sources found at
phosphoric acid manufacturing facilities (Wyoming DEQ 2006). Coal, natural gas, diesel fuel,
distillate fuel oil, and residual fuel oil are all possible fuel inputs. The Manufacturing Energy
Consumption Survey (MECS) data compiled by the Department of Energy (DOE) for NAICS
code 325312, "Phosphatic Fertilizers" which includes phosphoric acid production, indicates 57
percent of the total fuel energy consumption (i.e., excluding purchased electricity) is natural gas
and 39 percent is from a classification called "other fuels" (which includes steam and other
energy used to produce heat and power). No other specifics of this classification are given by
MECS.
3. Review of Existing Programs and Methodologies
Phosphoric acid production is not addressed by the 2006 IPCC guidelines, but the Inventory of
U.S. Greenhouse Gas Emissions and Sinks provides a method for estimating process related CO2
emissions from phosphoric acid production. CO2 emissions from production of phosphoric acid
from phosphate rock are estimated by multiplying the average amount of calcium carbonate
contained in the natural phosphate rock by the amount of phosphate rock that is used annually to
produce phosphoric acid. The CO2 emissions calculation methodology is based on the
assumption that all of the inorganic C (calcium carbonate) content of the phosphate rock reacts to
form CO2 in the phosphoric acid production process and is emitted with the stack gas. The
methodology also assumes that none of the organic C content of the phosphate rock is converted
to CO2 and that all of the organic C content remains in the phosphoric acid product.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
The carbonate content of phosphate rock varies depending upon where the material is mined.
The US inventory applies composition data for domestically mined and imported phosphate rock
provided by the Florida Institute of Phosphate Research to regional phosphate rock production
numbers to estimate emissions. Companies conduct analysis on the rock frequently to determine
the P2Os content and the level of impurities (Jasinski 2008). According to CF industries (Falls
2008), they analyze a composite of incoming phosphate rock for carbon contents on a daily
basis. The phosphate rock consumed or entering the digestion process is also measured on a
daily basis.
4. Options for Reporting Threshold
4.1 Emissions Thresholds
Four reporting threshold levels were considered for the phosphoric acid manufacturing sector.
The emission thresholds, 100,000, 25,000, 10,000, and 1,000 mtCO2e per year, were analyzed
based on production data.
4.2 Capacity Thresholds
Four capacity threshold levels were considered for the phosphoric acid manufacturing sector.
The thresholds, 1.5, 1.0, 0.5, and 0.15 million metric tons of phosphoric acid per year, were
analyzed based on the capacity of the manufacturing sites. Because only production data was
available, all facilities were assumed to operate at 90% of their capacity. The capacities were
calculated based on production values.
4.3 No Emissions Threshold
The no emissions threshold includes all phosphoric acid manufacturing facilities regardless of
their emissions or capacity.
4. 4 Analysis of Emissions and Facilities Covered Per Threshold Option
4.4.1 Emissions Thresholds
All threshold levels were found to incorporate the entire phosphoric acid manufacturing sector.
Table 2 provides the threshold analysis for the phosphoric acid manufacturing sector. The
threshold analysis estimated a total emissions profile for the phosphoric acid production sector of
3,838,036 mtCO2e. This total was the additive sum of process emissions (1,167,201 mtCC^e)
from the US GHG inventory and combustion emissions (2,670,836 mtCC^e) which are described
further below. The average emissions per facility equaled approximately 274,000 mtCC^e,
which placed all facilities above the maximum reporting threshold of 100,000 mtCC^e.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
Table 2. Threshold Analysis for Phosphoric Acid Production
Threshold
Level
(mtCO2e)
100,000
25,000
10,000
1,000
Process
Emissions
(mtCO2e /yr)
1,167,201
1,167,201
1,167,201
1,167,201
CO2
Emissions
(mtCO2e /yr)
2,670,836
2,670,836
2,670,836
2,670,836
Total
National
Emissions
(mtCO2e)
3,838,036
3,838,036
3,838,036
3,838,036
Number
of
Entities
14
14
14
14
Emissions Covered
mtCO2e /yr
3,838,036
3,838,036
3,838,036
3,838,036
%
100
100
100
100
Entities Covered
Number
14
14
14
14
%
100
100
100
100
Source: Calculations based on U.S. production data
Process emissions were calculated by multiplying a default factor for inorganic carbon content
within phosphate rock by the amount of phosphate rock used to produce phosphoric acid. The
default factor varies by the region which mined the phosphate rock; a separate factor is applied to
imported phosphate rock (See Table 3). It was not possible to prepare a detailed facility level
analysis of process-related emissions. The US GHG inventory method requires having facility
level information on the quantity of phosphate rock consumed which was not readily available.
Table 3. Chemical Composition of Phosphate Rock (percent by weight)
Composition
Total Carbon (as C)
Inorganic Carbon (as C)
Organic Carbon (as C)
Inorganic Carbon (as CO2)
Central Florida
1.60
1.00
0.60
3.67
North Florida
1.76
0.93
0.83
3.43
North
Carolina
(Calcined)
0.76
0.41
0.35
1.50
Idaho
(Calcined)
0.60
0.27
-
1.00
Morocco
1.56
1.46
0.10
5.00
Source: Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006
Calculations of process emissions followed the equation:
CO2 = AD * EF
Where:
CC>2 = process emissions of CC>2
AD = Phosphate rock consumption
EF = Regional chemical composition factor of phosphate rock
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
The emissions analysis is an overestimate because it includes emissions from triple super
phosphate and elemental phosphorus production. To calculate CC>2 emissions based on the
equation above, it was assumed that all phosphate rock mined is used to produce phosphoric
acid. However, approximately 7% of domestically-produced phosphate rock is used to
manufacture elemental phosphorus and other phosphorus-based chemicals. Therefore, some
greenhouse gas emissions resulting from the production of elemental phosphorus or triple super
phosphate are included in the emission estimates used in the EPA Inventory (U.S. EPA 2008).
Emissions from triple super phosphate production may not be wholly accounted for in the
process-related emissions estimate for phosphoric acid because the reaction to produce triple
super phosphate includes reacting phosphoric acid with phosphate rock. While the process-
related emissions from producing the phosphoric acid are accounted for by using phosphoric acid
as the activity data, the emissions from reacting phosphoric acid with additional phosphate rock
may be additive.
Emissions from elemental phosphorus production are not wholly accounted for in the emissions
estimate for phosphoric acid because the reaction to produce elemental phosphorus includes
reacting phosphate with petroleum coke. Consumption data was not available for the carbon-
containing input (petroleum coke); therefore, it has been omitted from this analysis. It is known,
however, that only a single facility in the United States currently produces elemental phosphorus
and that about 5% of the phosphate rock mined is utilized for elemental phosphorus production
(USGS 2007).
Combustion emissions from phosphoric acid production were estimated by using the Title V
permit issued to the J.R. Simplot facility in Rock Springs, WY that listed the number, type, and
fuel consumption rate of stationary emission sources. Two emission units were listed in the
permit; a packaged boiler assumed to use natural gas at a rate of 350 MMBtu/hr, and an auxiliary
boiler assumed to use natural gas at a rate of 106.5 MMBtu/hr. Assuming that each emission
unit within the facility operated at 90% capacity continuously (24 hours a day, 365 days a year)
emissions were estimated to be approximately 190,800 mt CC^e (Wyoming DEQ 2006).
4.4.2 Capacity Threshold
Capacity-based thresholds are not presented here because preliminary estimates indicate that all
facilities exceed the highest emissions-based thresholds.
4.4.3 No Emissions Threshold
The option of regulating all phosphoric acid manufacturing facilities regardless of their
emissions profile is similar to the emissions threshold option because at each threshold level all
phosphoric acid facilities would be regulated.
5. Options for Monitoring Methods
Three separate monitoring methods were considered for this technical support document: direct
measurement (Option 1), an input-based method (Option 2), and a simplified emission
calculation (Option 3). All of these options require annual reporting.
5.1 Option 1: Simplified Emission Calculations
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
Option 3 relies upon calculations based on each facility's raw material input and default carbon
content of the phosphate rock. Specifically, the quantity of phosphate rock and the regional
inorganic carbon percentage of the phosphate rack need to be known. The equation for
calculating emissions is:
CO2 = AD * EF
Where:
CO2 = process emissions of CO2
AD = Phosphate rock consumption
EF = Regional chemical composition factor of phosphate rock
The regional chemical composition factor of phosphate rock can be found in Table 3.
5.2 Option 2: Hybrid Method
Option 2 relies upon calculations based on each facility's raw material input. Specifically, the
quantity of phosphate rock and the percentage of inorganic carbon present in the phosphate rock
will need to be measured. An equation of the monitoring method is below:
E =V 4£*[/C *P]*^
m ^ 12 " " 2205
Where:
Em = Annual CO2 mass emissions from a wet-process phosphoric acid process
line m(metric tons)
44/12 = Ratio of molecular weights, CO2 to carbon
ICn = Inorganic carbon content of the batch of phosphate rock used during
month n, from the carbon analysis results (percent by weight, expressed as
a decimal fraction)
Pn = Mass of phosphate rock consumed in month n by wet-process phosphoric acid
process line m (tons)
m = Each wet-process phosphoric acid process line
z = Number of months during which the process line m operates
2000/2205 = Conversion factor to convert tons to metric tons.
As noted earlier, many of the data inputs for this method are readily available. The Phosphoric
Acid NSPS (40 CFR part 60, subpart T) requires continuous monitoring of phosphorus-bearing
material (rock) to process. In addition, only 3 facilities within the United States are not vertically
integrated with mines and may lack the necessary equipment to measure the inorganic carbon
weight percent of the rock. In general, inorganic carbon test results and monthly production data
should be readily available.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
5.3 Option 3: Direct Measurement using Continuous Emission Monitoring Data
(CEMS)
Another applicable monitoring method to estimate CC>2 emissions from phosphoric acid
production facilities for which the process emissions and/or combustion GHG emissions are
contained within a stack or vent is direct measurement using a Continuous Emissions Monitoring
System (CEMS). In the case of phosphoric acid facilities, each stack emits both process and
combustion emissions. Because a CEMS would continuously measure actual CO2 emissions at a
given phosphoric acid production facility when it is in operation, this method is the most
accurate monitoring method for determining GHG emissions from a specific source. The costs
for installing and operating a CEMS for direct measurements of GHG emissions from a given
phosphoric acid production facility would be higher than for using one of the other monitoring
method options. See stationary combustion TSD for information on estimating CH4 and N2O.
Direct measurements of the GHG concentration in the stack gas and the flow rate of the stack gas
can be made using a CEMS. Elements of a CEMS include a platform and sample probe within
the stack to withdraw a sample of the stack gas, an analyzer to measure the concentration of the
GHG (e.g., CC>2) in the stack gas, and a flow meter within the stack to measure the flow rate of
the stack gas. The emissions are calculated from the concentration of GHGs in the stack gas and
the flow rate of the stack gas. A CEMS continuously withdraws and analyzes a sample of the
stack gas and continuously measures the GHG concentration and flow rate of the stack gas.
6. Procedures for Estimating Missing Data
Options and considerations for missing data will vary depending on the proposed monitoring
method. Each option would require a complete record of all measured parameters as well as
parameters determined from company records that are used in the GHG emissions calculations
(e.g., carbon contents, monthly fuel consumption, etc.).
As noted, the Phosphoric Acid NSPS (40 CFR part 60, subpart T) requires continuous
monitoring of phosphorus-bearing material (rock) to process. This requirement, along with the
fact that the facility will closely monitor production inputs, results in low likelihood of missing
data. Additionally, only 3 facilities within the United States are not vertically integrated with
mines and may lack the necessary equipment to measure the inorganic carbon weight percent of
the rock. In general, inorganic carbon test results and monthly production data should be readily
available.
6.1 Procedures for Option 1: Simplified Emissions Calculations
For process sources that use a simplified emission calculation no missing data procedures would
apply because the emission calculation is performed using default emission factors and activity
data. Activity data such as production or consumption are readily available. Therefore, 100
percent data availability would be required.
6.2 Procedures for Option 2: Hybrid Method
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
For process sources that use a site-specific emission factor no missing data procedures would
apply because the site-specific emission factor is derived from the analysis of the most recent
phosphate rock batch and used in each calculation. The factor would be multiplied by the
process input rate, which is readily available. Therefore, 100 percent data availability would be
required.
6.3 Procedures for Option 3: Direct Measurement using CEMS
For options involving direct measurement of CC>2 emissions using CEMS, Part 75 establishes
procedures for the management of missing data. Specifically, the procedures for managing
missing CC>2 concentration data are specified in §75.35. In general, missing data from the
operation of the CEMS may be replaced with substitute data to determine the CC>2 emissions
during the period for which CEMS data are missing. Section 75.35(a) requires the owner or
operator of a unit with a CC>2 CEMS to substitute for missing CC>2 pollutant concentration data
using the procedures specified in paragraphs (b) and (d) of §75.35; paragraph (b) covers
operation of the system during the first 720 quality-assured operation hours for the CEMS, and
paragraph (d) covers operation of the system after the first 720 quality-assured operating hours
are completed.
During the first 720 quality-assured monitor operating hours following initial certification at a
particular unit or stack location, the owner or operator would be required to substitute CC>2
pollutant concentration data according to the procedures in §75.3 l(b). That is, if prior quality-
assured data exist, the owner or operator would be required to substitute for each hour of missing
data, the average of the data recorded by a certified monitor for the operating hour immediately
preceding and immediately following the hour for which data are missing. If there are no prior
quality-assured data, the owner or operator would have to substitute the maximum potential CC>2
concentration for the missing data.
Following the first 720 quality-assured monitor operating hours, the owner or operator would
have to follow the same missing data procedures for SC>2 specified in §75.33(b). The specific
methods used to estimate missing data would depend on the monitor data availability and the
duration of the missing data period.
7. QA/QC Requirements
Facilities should conduct quality assurance and quality control of the production (phosphate rock
feed rates, etc.) and consumption data, supplier information (e.g., carbon contents), and emission
estimates reported. Facilities are encouraged to prepare an in-depth quality assurance and quality
control plan which would include checks on production data, the carbon content information
received from the supplier and from the lab analysis, and calculations performed to estimate
GHG emissions. Several examples of QA/QC procedures are listed below.
7.1 Stationary Emissions
For QA/QC options for stationary combustion refer to EPA-HQ-OAR-2008-0508-004.
7.2 Process Emissions
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
Options and considerations for QA/QC will vary depending on the proposed monitoring method.
Each option would require unique QA/QC measures appropriate to the particular methodology
employed to ensure proper emission monitoring and reporting.
7.3 Data Management
Data management procedures should be included in the QA/QC Plan. Elements of the data
management procedures plan are as follows:
• Check for temporal consistency in production data, carbonate content data, and emission
estimate. If outliers exist, they should be explained by changes in the facility's
operations or other factors. A monitoring error is probable if differences between annual
data cannot be explained by:
o Changes in activity levels,
o Changes concerning fuels or input material,
o Changes concerning the emitting process (e.g. energy efficiency improvements)
(EU 2007).
• Determine the "reasonableness" of the emission estimate by comparing it to previous
year's estimates and relative to national emission estimate for the industry:
o Comparison of data on fuel or input material consumed by specific sources with
fuel or input material purchasing data and data on stock changes,
o Comparison of emission factors that have been calculated or obtained from the fuel
or input material supplier, to national or international reference emission factors of
comparable fuels or input materials
o Comparison of emission factors based on fuel analyses to national or international
reference emission factors of comparable fuels, or input materials,
o Comparison of measured and calculated emissions (EU 2007).
• Maintain data documentation, including comprehensive documentation of data received
through personal communication:
o Check that changes in data or methodology are documented
8. Types of Emissions to be Reported
Based on the existing programs and the emission sources at phosphoric acid production facilities,
GHG reporting for these facilities is limited to CCh, CH4, and N2O. Phosphoric acid facilities
should report both process (CO2) and combustion related (CC>2, CH4, and N2O) greenhouse gas
emissions. The data to be reported may very depending on monitoring options selected.
However, a phosphoric acid production facility should report its annual average phosphate rock
consumption, number of wet-process phosphoric acid lines, percent inorganic carbon in
phosphate rock consumed, annual phosphoric acid production and concentration, annual
phosphoric acid production capacity, electricity usage (kilowatt-hours), and annual operating
hours. For reporting options for stationary combustion refer to EPA-HQ-OAR-2008-0508-004.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
8.1 Other Information to be Reported
Additional data for verification could include process raw material and product feed rates and
carbon contents. Such data would illustrate the process operating conditions at which the
emissions monitoring data were obtained. EPA could use such data, for example to check the
reported emissions against activity-data-based emission factors for the process.
8.2 Additional Data to be Retained Onsite
Facilities should be required to retain data concerning monitoring of GHG emissions onsite for a
period of at least five years from the reporting year. For CEMS these data would include CEMS
monitoring system data including continuous-monitored GHG concentrations and stack gas flow
rates, calibration, and quality assurance records. Process data including process raw material and
product feed rates and carbonate contents should also be retained on site for a period of at least
five years from the reporting year. EPA could use such data to conduct trend analyses and
potentially to develop process or activity-specific emission factors for the process.
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Technical Support Document for Phosphoric Acid: Proposed Rule for Mandatory Reporting of Greenhouse Gases
9. References
EFMA (2000) "Production of Phosphoric Acid." Best Available Techniques for Pollution
Prevention and Control in the European Fertilizer Industry. Booklet 4 of 8. European Fertilizer
Manufacturers Association. Available online at
.
(EU 2007) Official Journal of the European Union, August 31, 2007. Commission Decision of
18 July 2007, "Establishing guidelines for the monitoring and reporting of greenhouse gas
emissions pursuant to Directive 2003/87/EC of the European Parliament and of the Council.
Available at http://eur-
lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:229:0001:0085:EN:PDF.
Falls (2008). Personal Communication between Harold Falls of CF Industries and Erin Redmond
of Research Triangle Institute (RTI), June 26, 2008.
IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories. The National
Greenhouse Gas Inventories Programme, The Intergovernmental Panel on Climate Change, H.S.
Eggleston, L. Buenida, K. Miwa, T Ngara, and K. Tanabe (eds.). Hayama, Kanagawa, Japan.
Jaskinski (2008). Personal Communication between Stephen Jasinski of the US Geological
Survey and Mausami Desai of US EPA. June 25th, 2008.
U.S. EPA (2008) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006. U.S.
Environmental Protection Agency, Washington D.C. USEPA #430-R-08-005.
U.S. EPA (2007) Climate Leaders, Inventory Guidance, Design Principles Guidance, Chapter 7
"Managing Inventory Quality". Available at
http://www.epa.gov/climateleaders/documents/resources/design_princ_ch7.pdf
U.S. EPA (2005) Clean Air Act National Stack Testing Guidance, U.S. Environmental
Protection Agency Office of Enforcement and Compliance Assurance, September 30, 2005.
www.epa.gov/compliance/resources/policies/monitoring/caa/stacktesting.pdf
U.S. EPA (2003) Part 75, Appendix Bl, Available at
http ://www. epa. gov/airmarkt/spm/rule/001OOOOOOB. htm.
USGS (2007) Minerals Yearbook: Phosphate Rock Annual Report. U.S. Geological Survey,
Reston, VA. Available online at:
http://minerals.usgs.gov/minerals/pubs/commodity/phosphate_rock/mybl -2007-phosp.pdf
Wyoming DEQ (2006) Air Quality Division Chapter 6, Section 3 Operating Permit. State of
Wyoming Department of Environmental Quality Cheyenne, Wyoming. Available online at:
http ://deq. state. wv.us/AOD/Title%20V%20Operating%20Permits/3 -1-125. fm.pdf
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