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Date: September 9, 2011

Subject: Confirmation of Fuels Combusted at Oil-fired Sources during Maximum Achievable 

Control Technology (MACT) Floor Performance Testing and Updated Floor Limits with 

Potential Source Subcategories for Oil-fired Generating Units

From: Jeffrey Cole (RTI International)

To: Bill Maxwell

OAQPS/SPPD/ESG (D243-01)

U.S. Environmental Protection Agency

Research Triangle Park, NC 27711

Summary of Technical Directive

The EPA requested that RTI determine what fuel oil type (or other blended fuel) was combusted during 

the Mercury Air Toxics Study (MATS) information collection request (ICR) MACT floor performance 

tests used in the floor analysis for “oil-fired units.” The EPA work assignment manager (WAM) requested 

confirmation that the remainder of the emissions data received since proposal (i.e., Puerto Rico and Guam 

facilities) had been entered into the MACT floor dataset. The EPA WAM also requested that RTI produce 

updated statistical analyses to incorporate the new data and an analyses to evaluate how establishing 

potential subcategories for fuel oil grade (No. 2 and No. 6) and continental location (i.e., differentiating 

continental sources located in North America from non-continental sources) would affect the various 

MACT floor limits for oil-fired units.

Background

The EPA received comments from industry advocates for oil-fired EGUs during the proposed rule’s 

public comment period that the fuel types listed for some oil-fired units in the proposed rule’s emissions

data were incorrect. RTI was tasked with contacting all companies participating in the MATS ICR that 

had uploaded data from testing of oil-fired units to confirm the fuels used during MACT floor 

performance tests.

Then the EPA requested that once all the missing oil-fired EGU data had been loaded, RTI conduct a

what-if analysis of a subcategorization scheme based on fuel oil grade (No. 2 and No. 6) and unit 

location (continental or non-continental). The reason for this analysis was to determine the validity of 

concerns expressed by commenters regarding the inherent differences between fuel grades and fuel 

sources (i.e., continental versus non-continental) that would affect a unit’s ability to meet a standard based 

on the combination of fuel grades/sources.

Technical Approach

With regard to the commenter’s assertion that erroneous fuel types were listed for oil-fired units within 

the proposal dataset, RTI identified two sources that were burning atypical fuels during the oil-fired 

MACT floor performance tests and excluded those sources from further analyses. 
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With regard to the potential subcategorization scheme based on fuel oil grade and facility location 

(continental vs. non-continental), subsequent MACT floor calculations were completed for the following 

groupings of EGUs:

Group 1. All No. 2 and No. 6 oil-fired, continental, and non-continental sources.

Group 2. All No. 2 oil-fired, continental sources; there are no non-continental No. 2 oil-fired EGUs 

meeting the proposed applicability criteria.

Group 3. All No. 6 oil-fired, continental, and non-continental sources.

Group 4. All No. 2 and No. 6 oil-fired, continental sources.

Group 5. All No. 6 oil-fired, non-continental sources; there are no non-continental No. 2 oil-fired 

EGUs meeting the proposed applicability criteria.

The number of sources included in each MACT floor data set for each potential subcategory was 

determined based on the number of sources with available emissions data using the criteria of CAA 

section 112(d)(3).

Data Collection and Fuel Verification

RTI contacted the operators of the oil-fired units that composed the MACT floor data set to confirm the

fuel(s) used during the MACT floor performance tests. In confirming the fuel blends for the proposal, RTI 

originally determined that there were five units which blended 10 percent or greater natural gas (based on 

the respondents reporting of natural gas co-firing) and excluded these five sources from the MACT floor 

analyses because inclusion of sources using 10 percent or more natural gas could bias HAP emissions low 

and make the floor potentially unachievable for units firing greater than 90 percent fuel oil. However,

during this post-proposal fuel verification, RTI found two additional sources that should be excluded from 

the floor analyses:

1. C.D. McIntosh, Unit 2 (ORIS Code 676) which averages firing only 30 percent fuel oil with 

natural gas, and 

2. Santee Cooper – Jefferies, Unit 2 (ORIS Code 3319) which is operated as a seasonal peaking and 

uses approximately 97 percent used motor oil and 3 percent (No. 2 fuel oil).

Also, the Guam Power Authority provided comments (Docket ID: EPA-HQ-OAR-2009-0234-18433) that 

indicated that natural gas was not available on the island and confirmed that only residual fuel oil was

used in the largest generating units on the island.

Table 1 shows the fuel types confirmed for all oil-fired units in the post-proposal review. The units 

excluded from MACT floor analyses are listed at the bottom of the table. Table 1 shows both the oil-fired 

units that were tested under Part III of the ICR and those that submitted Hg emissions data under Part II 

of the ICR.

As shown in Table 1, there are six units located at three continental U.S. facilities (two units each) that 

combust No. 2 fuel oil, exclusively. At one of these three facilities, two of their No. 2, oil-fired EGUs 
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Table 1. Fuel Used During MACT Floor Performance Tests for Oil-fired Sources

Facility ID Plant Name Unit ID Location Primary Fuel Other Fuel(s) Other Fuel Description

546 Montville Power 5 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

548 Norwalk Harbor Station 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

562 Middletown Power Station 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

617 Port Everglades PPE03 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

617 Port Everglades PPE04 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

621 Turkey Point PTF01 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

621 Turkey Point PTF02 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

638 Suwannee River Suw_Cfg_2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

638 Suwannee River Suw_Cfg_3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

638 Suwannee River Suw_Cfg_1 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

667 Northside 3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

764 Honolulu Power Plant H8 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

764 Honolulu Power Plant H9 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

765 Kahe Power Plant K3 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

765 Kahe Power Plant K1 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

766 Waiau Power Plant W6 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

766 Waiau Power Plant W7 Outside Continental U.S. (Hawaii) No. 6 Fuel Oil (residual or bunker C)

990 AES Harding Street 09 Inside Continental U.S. No. 2 Fuel Oil (distillate)

990 AES Harding Street 10 Inside Continental U.S. No. 2 Fuel Oil (distillate)

991 IP&L Eagle Valley 1, 2 (shared stack) Inside Continental U.S. No. 2 Fuel Oil (distillate)

1507 William F Wyman 1 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

1507 William F Wyman 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

1564 Vienna Unit 8 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

1642 West Springfield Unit 3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

1682 Cleary Flood 8 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) No. 2 Fuel Oil (distillate) 7-10% No. 2; 90-93% No. 6

2050 Baxter Wilson 001 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2378 BL England 3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2411 PSEG Sewaren Generating Station SEWU4E4PT4OS0 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2411 PSEG Sewaren Generating Station SEWU3E3PT3OS0 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2411 PSEG Sewaren Generating Station SEWU1E1PT1OS0 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2480 Dynegy Danskammer Generation 

Station 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2480 Dynegy Danskammer Generation 

Station 1 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

2493 East River 60 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas1

2516 Northport 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas1

2516 Northport 3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas1

 

1

 Accounting for <10 percent of the total heat content of the blended fuel mixture.
Table 1. Fuel Used During MACT Floor Performance Tests for Oil-fired Sources (cont’d)

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Facility ID Plant Name Unit ID Location Primary Fuel Other Fuel(s) Other Fuel Description

2517 Port Jefferson 4 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas1

3148 Martins Creek U3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

3148 Martins Creek U4 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

3159 Cromby Unit 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

3181 Mitchell Power Station 1 Inside Continental U.S. No. 2 Fuel Oil (distillate)

3181 Mitchell Power Station 3 Inside Continental U.S. No. 2 Fuel Oil (distillate)

3804 Possum Point Unit 5 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

3809 Yorktown Unit 3 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

6042 Manatee PMT01 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

6042 Manatee PMT02 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

6043 Martin PMR01 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

6043 Martin PMR02 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

8054 Gerald Andrus 001 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

8906 Astoria A-S0003 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C)

40429 Cabras Power Plant 2 Outside Continental U.S. (Guam) No. 6 Fuel Oil (residual or bunker C)

70000 Aguirre Aguirre 1 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70000 Aguirre Aguirre 2 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70002 Costa Sur Costa Sur 3 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70002 Costa Sur Costa Sur 6 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70003 San Juan Plant San Juan 7 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70003 San Juan Plant San Juan 8 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70003 San Juan Plant San Juan 9 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

70003 San Juan Plant San Juan 10 Outside Continental U.S. (Puerto Rico) No. 6 Fuel Oil (residual or bunker C)

Note: The units below were not used in any MACT Floor analyses because of their fuel blending.

676 C.D. McIntosh, Jr. Unit 2 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas2

3161 Eddystone Unit 3, Unit 4 

(shared stack) Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas2

2500 Ravenswood Power Station 20 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas2

2500 Ravenswood Power Station 30 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas2

3319 Santee Cooper-Jefferies Unit 2 Inside Continental U.S. Used Motor Oil3 No. 2 Fuel Oil (distillate) 97% Used Motor Oil / 3% No. 2

Fuel Oil (distillate)

8002 Newington 1 Inside Continental U.S. No. 6 Fuel Oil (residual or bunker C) other Natural Gas2

 

2

 Accounting for >10 percent of the total heat content of the blended fuel mixture.

3

 As noted in the memorandum’s text, this use of used motor oil for fuel was deemed by the EPA to be incomparable with other oil-fired EGUs in these MACT Floor analyses. 
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share a common stack (IP&L Eagle Valley, Units 1 and 2). In the statistical spreadsheets, RTI treated data 

from EGUs sharing a common stack as separate sources however; the source did not provide a complete 

set of metals data. The result in this case was that, while most of the analyses resulted in a data set of six 

No. 2 oil-fired sources and a MACT floor analysis based on the top five sources, complete “total HAP 

metals” and cobalt emissions data were available for only four No. 2 oil-fired sources.

RTI is waiting for one company to submit new data to correct a data entry error that has prevented the 

update of the HCl and HF acid gas MACT floor results for oil-fired EGUs. This company operates oilfired EGUs outside of the continental U.S. and, since such ICR data is limited, its inclusion is essential to 

complete those MACT floor analyses.

Emission Limit Determinations

In this memorandum, RTI is presenting updated MACT floors for mercury (Hg), total metals (with and 

without Hg), and non-mercury HAP metals for all the oil-fired units that provided complete data 

submittals under the MATS ICR. RTI will complete the analysis of the acid gas MACT floors after these 

data are received.

After compiling the final set of available oil-fired emissions data (Group 1), the dataset was divided into 

the previously mentioned five potential subcategories. The datasets were sorted and the statistical 

analyses for upper predictive limit (UPL) were completed for each of the potential oil-fired subcategories. 

The statistical analysis calculated the 99th percentile UPL emission limits based on the average emission 

rates (in contrast to the individual run data) from all available oil-fired performance tests. This use of 

average emission rates was consistent with how EPA performed its statistical analysis spreadsheets for the 

proposed rule’s MACT floors for oil-fired units.

Summary of Findings

It should be noted that when comparing the proposed MACT floors with the updated MACT floors from 

this analysis, some differences will be noticed that are attributed to the rounding conventions utilized for 

the proposed rule. In Tables 2 through 53 the data in the “proposed” rows in each table reflect the 

rounding conventions used in the proposal to convert the UPL calculated values to the form of the 

standard. All other rows reflect the complete set of updated data without rounding. By examining the 

UPL, the reader can determine if the change in value is due to a data change or to the proposal’s rounding 

convention.

The results of the subcategorization analysis are presented in a series of tables with all of the potential 

subcategories reflected in each table. The MACT floor values are presented for each pollutant in a group 

of four tables; existing input-based (i.e. lb/MMBtu), existing output-based (i.e. lb/MW), new outputbased (i.e. lb/MW), and a table describing the data set used to calculate the floor values.
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Subcategorization Analysis Results

Mercury

Tables 2, 3, and 4, show the calculated MACT floors for each of the potential oil subcategories. Table 5 

shows the number of sources with available emissions data in each potential subcategory and the 

respective number of sources used in the floor analysis for the subcategory.

As shown in the tables, total metals are approximately twice as high for No. 6 oil as for No. 2 oil. It is 

noteworthy that Hg emission rates from the top five No. 2 oil sources are approximately an order of 

magnitude higher than the top six residual oil sources. 

Total Metals With and Without Hg

Tables 6, 7, and 8 show the MACT floors calculated for total metals (including Hg) with subcategories

for oil grades and continental locations. Table 9 shows the number of sources with available emissions 

data in each potential subcategory and the respective number of sources used in the floor analysis for the 

subcategory.

Tables 10, 11 and 12 show the MACT floors calculated for total metals only (not including Hg) with 

subcategories for oil grades and continental locations. Table 13 shows the number of sources with 

available emissions data in each potential subcategory and the respective number of sources used in the 

floor analysis for the subcategory. Note that the low levels of Hg emissions relative to the other metals 

make the non-Hg metals MACT floor and the total metals MACT floor (including Hg) essentially 

identical.

RTI assured that all performance test averages used in the analyses for total metals (including Hg) were 

based on complete sets of all HAP metals. This criteria generally yielded smaller data sets for the total 

metals analyses than for individual metals analyses because any source test that omitted one or more HAP 

metals was excluded from the total metals analyses. As mentioned earlier in this memorandum, the 

complete total metals data set criteria removed two of the six No. 2 oil-fired sources (IP&L Eagle Valley

Units 1 and 2) leaving only 4 emission sources with available data for the total metals analyses for 

distillate sources.

The updated results indicate there is a marked difference in total metals emissions from units firing No. 2 

fuel oil versus units firing No. 6 fuel oil. The updated results also indicate that there is a substantial 

difference in total metals emissions from units operated in the continental U.S. versus non-continental 

units. The total metals MACT floors for units outside the continental U.S. are approximately 62 times 

greater than the total metals floors for non-continental sources. This large difference is because all floor 

units in the continental data set either burn No. 2 fuel oil (without PM control) or burn No. 6 fuel oil (with 

installed ESPs). This is would be expected given the potential for metals to have been removed during 

refining of the No. 2 fuel oil and this phenomenon is evidenced as well in the results reflected below for 

the individual metals. If we compare the total metals floors for the units burning No. 6 fuel oil in the 

continental U.S. to the oil-fired units operated outside the continental U.S. (which all burn No. 6 fuel oil), 

the uncontrolled, non-continental sources are found to have emissions approximately 12 times higher than 

the ESP controlled continental sources. 
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During completion of the updated analyses it was determined that the original MACT floor data set only 

had 42 valid total metals data sets. Similarly, the updated data set only has 42 valid total metals data sets.

Therefore, the MACT floor total metals data set for existing oil-fired units should have been comprised of 

only five sources instead of the seven sources used for the proposed total metals floors. For the total 

metals UPL calculations, use of five sources rather than seven sources in combination with the updated 

data set resulted in change to the MACT floor (including variability) of approximately 10 percent; 

however this change was not sufficiently large to change the rounded value that was proposed as the 

floor.

Antimony

Tables 14, 15, and 16 show the MACT floors calculated for antimony with subcategories for oil grades 

and continental locations. Table 17 shows the number of sources with available emissions data in each 

potential subcategory for antimony and the respective number of sources used in the floor analysis for the 

subcategory.

The results indicate that there is a marked difference in the antimony emissions from sources firing No. 2

fuel oil compared to sources firing No. 6 fuel oil. The MACT floor for the potential No. 6 fuel oil 

subcategory is approximately 5 times greater than the No. 2 fuel oil subcategory for antimony. There is 

also a notable difference between antimony emissions from units operated in the continental U.S. as 

opposed to units operated outside the continental United States. The antimony MACT floor for units 

outside the continental U.S. is approximately 5 times greater than that of the antimony MACT floor for 

units inside the continental United States.

Arsenic

Tables 18, 19, and 20 show the MACT floors calculated for arsenic with subcategories for oil grades and 

continental locations. Table 21 shows the number of sources with available emissions data in each 

potential subcategory for arsenic and the respective number of sources used in the floor analysis for the

subcategory.

The results indicate that there is a marked difference in the arsenic emissions from units firing No. 2 vs. 

No. 6 fuel oil. The No. 2 fuel oil arsenic MACT floor is over 2 times greater than that of the No. 6 fuel oil 

arsenic MACT floor. There is also a substantial difference between arsenic emissions from units operated 

in the continental U.S. as opposed to units operated outside the continental United States. The arsenic 

MACT floor for units outside the continental U.S. is approximately 8 times greater than that of the arsenic 

MACT floor for units inside the continental United States.

Beryllium

Tables 22, 23, and 24 show the MACT floors calculated for beryllium with subcategories for oil grades 

and continental locations. Table 25 shows the number of sources with available emissions data in each 

potential subcategory for beryllium and the respective number of sources used in the floor analysis for the 

subcategory.

The results indicate that there is a little difference in the beryllium emissions from units firing No. 2 vs. 

No. 6 fuel oil (approximately 1 percent). However, there is a substantial difference between beryllium 
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emissions from units operated in the continental U.S. as opposed to units operated outside the continental 

United States. The beryllium MACT floor for units outside the continental U.S. is approximately 8 times 

greater than that of the beryllium MACT floor for units inside the continental United States.

Cadmium

Tables 26, 27, and 28 show the MACT floors calculated for cadmium with subcategories for oil grades 

and continental locations. Table 29 shows the number of sources with available emissions data in each 

potential subcategory for cadmium and the respective number of sources used in the floor analysis for the 

subcategory.

The results indicate that there is a marked difference in the cadmium emissions from units firing No. 2 vs. 

No. 6 fuel oil. The No. 2 fuel oil cadmium MACT floor is approximately 4 times greater than that of the 

No. 6 fuel oil cadmium MACT floor. There is also a difference between cadmium emissions from units 

operated in the continental U.S. as opposed to units operated outside the continental United States. The 

cadmium MACT floor for units outside the continental U.S. is approximately 2 times greater than that of 

the cadmium MACT floor for units inside the continental United States.

Cobalt

Tables 30, 31, and 32 show the MACT floors calculated for cobalt with subcategories for oil grades and 

continental locations. Table 33 shows the number of sources with available emissions data in each 

potential subcategory for cobalt and the respective number of sources used in the floor analysis for the 

subcategory. It should be noted that RTI did not receive cobalt data with each of the Method 29 results 

submitted under the ICR. This caused some of the cobalt MACT floor data sets to include fewer sources

than the data sets for other individual metals. These incomplete Method 29 results are also the reason the 

total metals floors data sets having fewer sources than other individual metals floor data sets.

The results indicate that there is a substantial difference in the cobalt emissions from units firing No. 2 vs. 

No. 6 fuel oil. The No. 2 fuel oil cobalt MACT floor is approximately 7 times greater than that of the No. 

6 fuel oil cobalt MACT floor. There is also a substantial difference between cobalt emissions from units 

operated in the continental U.S. as opposed to units operated outside the continental United States. The 

cobalt MACT floor for units outside the continental U.S. is approximately 54 times greater than that of 

the cobalt MACT floor for units inside the continental United States. This large difference is because the 

floor units inside the continental U.S. MACT floor are all burning No. 2 fuel oil. If we compare cobalt 

emissions for the units burning No. 6 fuel oil in the continental U.S. (i.e., the No. 6 fuel only cobalt 

MACT floor) as opposed to units operated outside the continental U.S. (which all burn No. 6 fuel oil) a 

difference of 18 times is found. While this factor is less than the 54 times calculated above, it should be 

also noted that the No. 6 fuel only MACT floor (for cobalt emissions from sources within the continental 

U.S.) contains five sources that are all controlled by ESPs.

During completion of the updated analyses it was determined that the original MACT floor data set only 

had 44 valid cobalt data sets. Similarly, the updated data set only has 44 valid cobalt data sets. Therefore, 

the MACT floor cobalt data set for existing oil-fired units should have been comprised of only five 

sources instead of the seven sources used for the cobalt proposed floors. This reduced number of data 

averages was due to incomplete data submittals. For the cobalt UPL calculations, use of five sources 
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rather than seven sources combined with the updated data set resulted in change to the MACT floor 

(including variability) of approximately 10 percent; however this change was not sufficiently large to 

change the rounded value that was proposed as the floor.

Chromium

Tables 34, 35, and 36 show the MACT floors calculated for chromium with subcategories for oil grades 

and continental locations. Table 37 shows the number of sources with available emissions data in each 

potential subcategory for chromium and the respective number of sources used in the floor analysis for 

the subcategory.

The results indicate that there is a marked difference in the chromium emissions from units firing No. 2 

vs. No. 6 fuel oil. The No. 2 fuel oil chromium MACT floor is approximately 2 times greater than that of 

the No. 6 fuel oil chromium MACT floor. There is also a difference between chromium emissions from 

units operated in the continental U.S. as opposed to units operated outside the continental United States. 

The chromium MACT floor for units outside the continental U.S. is approximately 3 times greater than 

that of the chromium MACT floor for units inside the continental United States.

Lead

Tables 38, 39, and 40 show the MACT floors calculated for lead with subcategories for oil grades and 

continental locations. Table 41 shows the number of sources with available emissions data in each 

potential subcategory for lead and the respective number of sources used in the floor analysis for the 

subcategory.

The results indicate that there is a substantial difference in the lead emissions from units firing No. 2 vs. 

No. 6 fuel oil. The No. 2 fuel oil lead MACT floor is approximately 6 times greater than that of the No. 6

fuel oil lead MACT floor. There is also a small difference between lead emissions from units operated in 

the continental U.S. as opposed to units operated outside the continental United States. The lead MACT 

floor for units outside the continental U.S. is approximately 1.3 times greater than that of the lead MACT 

floor for units inside the continental United States.

Manganese

Tables 42, 43, and 44 show the MACT floors calculated for manganese with subcategories for oil grades 

and continental locations. Table 45 shows the number of sources with available emissions data in each 

potential subcategory for manganese and the respective number of sources used in the floor analysis for 

the subcategory.

The results indicate that there is a marked difference in the manganese emissions from units firing No. 2 

vs. No. 6 fuel oil. The No. 6 fuel oil manganese MACT floor is approximately 2.5 times greater than that 

of the No. 2 fuel oil manganese MACT floor. There is also a substantial difference between manganese 

emissions from units operated in the continental U.S. as opposed to units operated outside the continental 

United States. The manganese MACT floor for units outside the continental U.S. is approximately 7 times 

greater than that of the manganese MACT floor for units inside the continental United States.
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Nickel

Tables 46, 47, and 48 show the MACT floors calculated for nickel with subcategories for oil grades and 

continental locations. Table 49 shows the number of sources in each subcategory for nickel and the 

respective number of sources used in the floor analysis for the subcategory.

The results indicate that there is a substantial difference in the nickel emissions from units firing No. 2 vs. 

No. 6 fuel oil. The No. 6 fuel oil nickel MACT floor is approximately 9 times greater than that of the No. 

2 fuel oil nickel MACT floor. There is also a very substantial difference between nickel emissions from 

units operated in the continental U.S. as opposed to units operated outside the continental United States. 

The nickel MACT floor for units outside the continental U.S. is approximately 94 times greater than that 

of the nickel MACT floor for units inside the continental United States. This large difference is because 

all floor units in the continental data set burn No. 2 fuel oil (without PM control). If we compare nickel

floors for the units burning No. 6 fuel oil in the continental U.S. to the oil-fired units operated outside the 

continental U.S. (which all burn No. 6 fuel oil), the uncontrolled, non-continental sources are found to 

have emissions approximately 10 times higher than the ESP controlled continental sources. 

Selenium

Tables 50, 51, and 52 show the MACT floors calculated for selenium with subcategories for oil grades 

and continental locations. Table 53 shows the number of sources in each subcategory and the respective 

number of sources used in the floor analysis for the subcategory.

The results indicate that there is little difference in the selenium emissions from units firing No. 2 vs. No. 

6 fuel oil (approximately 7 percent). There is a difference between selenium emissions from units 

operated in the continental U.S. as opposed to units operated outside the continental United States. The 

selenium MACT floor for units outside the continental U.S. is approximately 2 times greater than that of 

the selenium MACT floor for units inside the continental United States.
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Conclusions

Approximately 90 percent of oil-fired sources responding to the ICR burn almost exclusively No. 6 fuel 

oil. Approximately 12 percent of the No. 6 oil fired sources are controlled by ESPs only and about17 

percent controlled by multiclones only. As shown in the following table, nickel and manganese are the 

predominant metal emitted from No. 6 oil-fired units that are controlled by ESPs. For No. 2 oil-fired units 

without PM controls, the predominant metals emitted are cobalt and lead. A comparison of the total 

metals emissions indicates that the best-controlled No. 6 oil units (controlled by ESPs) emitted 

approximately 60 percent more total metals than uncontrolled No. 2 oil units. 

Pollutant

No. 2 Fuel Only

Floor value (lb/TBtu)

No. 6 Fuel Only

Floor value (lb/TBtu)

Comparison of Mean Emission Rates 

with Variability (UPL)

As 2.479E+00 1.146E+00 Uncontrolled No. 2 Oil Higher

Be 7.000E-02 7.000E-02 Essentially No Difference

Cd 3.952E-01 1.105E-01 Uncontrolled No. 2 Oil Higher

Co 1.925E+01 2.746E+00 Uncontrolled No. 2 Oil Higher

Cr 4.944E+00 2.387E+00 Uncontrolled No. 2 Oil Higher

Mn 5.071E+00 1.272E+01 ESP Controlled No. 6 Oil Higher

Pb 1.593E+01 2.466E+00 Uncontrolled No. 2 Oil Higher

Sb 2.261E-01 1.216E+00 ESP Controlled No. 6 Oil Higher

Se 1.370E+00 1.473E+00 ESP Controlled No. 6 Oil Higher

Nickel 5.541E+00 5.008E+01 ESP Controlled No. 6 Oil Higher

Pollutant

No. 2 Fuel Only

Floor value (lb/MMBtu)

No. 6 Fuel Only

Floor value (lb/MMBtu)

Comparison of Mean Emission Rates 

with Variability (UPL)

Total Metals + 

Hg 6.148E+01 9.933E+01 ESP Controlled No. 6 Oil Higher

While the data in the preceding table supports the premise in a number of public comments that a well 

controlled No.6 oil-fired unit cannot achieve the total metals emission rate of an uncontrolled No. 2 oilfired unit, the data indicates that ESP-controlled No. 6 oil sources can approach the total metals emission 

rates achieved by uncontrolled No. 2 oil-fired sources and in some cases achieve lower emission rates of 

individual metals. 

Some commenters suggested that the EPA should establish a subcategory based on the continental 

location of a unit due to differences in the metals content of the oil from continental versus noncontinental sources. The public comments from several companies that operate No. 6 oil-fired units, 

however, focused on the difference between the total metals contents of No. 2 oil and No. 6 oil and not on 

the difference between the mercury content of the different oil grades.

With regard to mercury, RTI found that based on the fuel analyses received, mercury makes up less than 

one percent of the metals content of fuel oils used during performance testing and our analysis here 

indicates that the correlation between mercury content and fuel grade is not as clear as the relationship 

between the other metals content and fuel grade.
12

As noted in the work of Wilhelm (see Appendix A), more than half of the crude oil that is processed in 

the United States is imported so the long-term average concentrations in domestic fuel oils are likely to 

approach the world wide average. The ICR data for uncontrolled No. 6 oil-fired sources supports 

Wilhelm’s assertion because the average of all emission rates for uncontrolled, non-continental sources 

was within a 98 percent agreement with the average of the uncontrolled continental sources. 

The data in the preceding summary table indicates that effective PM controls can mitigate emissions of 

trace constituents (such as metals) from No.6 oil-fired sources. However, there are no sources outside of 

the continental United States equipped with any form of PM control or that burn any No. 2 fuel oil. This

lack of PM controls on the non-continental sources is the primary factor accounting for the higher 

emissions from non-continental sources, and not the origin of the crude oil. Based on this data analysis, it 

is our opinion that subcategorization by fuel oil type may be warranted; however, subcategorization by 

continental location due to crude oil source would not be warranted.
13

Mercury

Table 2. Existing Mercury (Hg) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Mercury (Proposed, 3/16/11) 1.9880E-08 4.8170E-08 7 0.05 lb/TBtu

Mercury (Updated) 1.8708E-08 4.5807E-08 7 0.05 lb/TBtu

Mercury (Updated, No. 2 Fuel Oil Only) 1.3987E-07 3.3913E-07 5 0.34 lb/TBtu

Mercury (Updated, No. 6 Fuel Oil Only) 1.7331E-08 4.5986E-08 6 0.05 lb/TBtu

Mercury (Updated, Inside Continental U.S.) 1.8432E-08 5.9878E-08 5 0.06 lb/TBtu

Mercury (Updated, Outside Continental U.S.) 2.4958E-08 4.3820E-08 5 0.04 lb/TBtu

Table 3. Existing Mercury (Hg) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Mercury (Proposed, 3/16/11) 2.2752E-07 6.1287E-07 7 0.0007 lb/GWh

Mercury (Updated) 1.9251E-07 4.8248E-07 7 0.0005 lb/GWh

Mercury (Updated, No. 2 Fuel Oil Only) 1.8549E-06 4.5684E-06 5 0.005 lb/GWh

Mercury (Updated, No. 6 Fuel Oil Only) 1.7745E-07 4.8226E-07 6 0.0005 lb/GWh

Mercury (Updated, Inside Continental U.S.) 2.2616E-07 8.2568E-07 5 0.0008 lb/GWh

Mercury (Updated, Outside Continental U.S.) 2.4618E-07 4.4299E-07 5 0.0004 lb/GWh
14

Table 4. New Mercury (Hg) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Mercury (Proposed, 3/16/11) 6.4837E-08 9.3613E-08 1 0.0001 lb/GWh

Mercury (Updated) 6.4837E-08 9.3613E-08 1 0.0001 lb/GWh

Mercury (Updated, No. 2 Fuel Oil Only) 1.2567E-06 5.3601E-06 1 0.005 lb/GWh

Mercury (Updated, No. 6 Fuel Oil Only) 6.4837E-08 9.3613E-08 1 0.0001 lb/GWh

Mercury (Updated, Inside Continental U.S.) 6.4837E-08 9.3613E-08 1 0.0001 lb/GWh

Mercury (Updated, Outside Continental U.S.) 1.6618E-07 1.8700E-06 1 0.002 lb/GWh

Table 5. Number of Data Averages in Each Subcategory and Number of Units in Each Mercury (Hg) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Mercury (Updated) 58 (all data) 7

Mercury (Updated, No. 2 Fuel Oil Only) 6 5

Mercury (Updated, No. 6 Fuel Oil Only) 52 6

Mercury (Updated, Inside Continental U.S.) 44 5

Mercury (Updated, Outside Continental U.S.) 14 5
15

Total Metals + Mercury (Hg) and Total Metals Only

Table 6. Existing Total Metals + Mercury (Hg) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Total Metals + Hg (Proposed, 3/16/11) 1.1024E-05 2.1337E-05 7

4

0.00003 lb/MMBtu

Total Metals + Hg (Updated) 1.0259E-05 2.4225E-05 5 0.00002 lb/MMBtu

Total Metals + Hg (Updated, No. 2 Fuel Oil Only) 1.4738E-05 6.1478E-05 4 0.00006 lb/MMBtu

Total Metals + Hg (Updated, No. 6 Fuel Oil Only) 2.8607E-05 9.9329E-05 5 0.0001 lb/MMBtu

Total Metals + Hg (Updated, Inside Continental U.S.) 8.8728E-06 1.7094E-05 4 0.00002 lb/MMBtu

Total Metals + Hg (Updated, Outside Continental U.S.) 6.5341E-04 1.2286E-03 5 0.00123 lb/MMBtu

Table 7. Existing Total Metals + Mercury (Hg) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Total Metals + Hg (Proposed, 3/16/11) 1.3679E-04 2.8745E-04 7

5

0.0003 lb/MWh

Total Metals + Hg (Updated) 1.2695E-04 3.3597E-04 5 0.0003 lb/MWh

Total Metals + Hg (Updated, No. 2 Fuel Oil Only) 2.0620E-04 8.7628E-04 4 0.0009 lb/MWh

Total Metals + Hg (Updated, No. 6 Fuel Oil Only) 3.0014E-04 1.0779E-03 5 0.0011 lb/MWh

Total Metals + Hg (Updated, Inside Continental U.S.) 1.0481E-04 1.7459E-04 4 0.0002 lb/MWh

Total Metals + Hg (Updated, Outside Continental U.S.) 6.8071E-03 1.2518E-02 5 0.0125 lb/MWh

 

4

The data set only contains 42 data averages (see Table 9); therefore, the proposed Total Metals + Hg MACT floor for existing oil-fired units should have only included five 

emission averages instead of just seven. 

5

The data set only contains 42 data averages (see Table 9); therefore, the proposed Total Metals + Hg MACT floor for existing oil-fired units should have only included five 

emission averages instead of just seven. 
16

Table 8. New Total Metals + Mercury (Hg) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Total Metals + Hg (Proposed, 3/16/11) 8.7795E-05 3.3172E-04 1 0.0003 lb/MWh

Total Metals + Hg (Updated) 8.7795E-05 3.3172E-04 1 0.00033 lb/MWh

Total Metals + Hg (Updated, No. 2 Fuel Oil Only) 1.0046E-04 2.6415E-04 1 0.00026 lb/MWh

Total Metals + Hg (Updated, No. 6 Fuel Oil Only) 8.7795E-05 3.3172E-04 1 0.00033 lb/MWh

Total Metals + Hg (Updated, Inside Continental U.S.) 8.7795E-05 3.3172E-04 1 0.00033 lb/MWh

Total Metals + Hg (Updated, Outside Continental U.S.) 5.0411E-03 6.2527E-03 1 0.00625 lb/MWh

Table 9. Number of Data Averages in Each Subcategory and Number of Units in Each Total Metals Mercury (Hg) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Total Metals + Hg (Updated) 42 (all data) 5

Total Metals + Hg (Updated, No. 2 Fuel Oil Only) 4 4

Total Metals + Hg (Updated, No. 6 Fuel Oil Only) 38 5

Total Metals + Hg (Updated, Inside Continental U.S.) 35 4

Total Metals + Hg (Updated, Outside Continental U.S.) 7 5
17

Table 10. Existing Total Metals MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Total Metals (Proposed, 3/16/11) 1.0905E-05 2.1072E-05 7

6

0.00003 lb/MMBtu

Total Metals (Updated) 1.0148E-05 2.3899E-05 5 0.00002 lb/MMBtu

Total Metals (Updated, No. 2 Fuel Oil Only) 1.4559E-05 6.0841E-05 4 0.00006 lb/MMBtu

Total Metals (Updated, No. 6 Fuel Oil Only) 2.8547E-05 9.9293E-05 5 0.0001 lb/MMBtu

Total Metals (Updated, Inside Continental U.S.) 8.7881E-06 1.7044E-05 4 0.00002 lb/MMBtu

Total Metals (Updated, Outside Continental U.S.) 6.5338E-04 1.2285E-03 5 0.00123 lb/MMBtu

Table 11. Existing Total Metals MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Total Metals (Proposed, 3/16/11) 1.3527E-04 2.8348E-04 7

7

0.0003 lb/MWh

Total Metals (Updated) 1.2551E-04 3.3081E-04 5 0.0003 lb/MWh

Total Metals (Updated, No. 2 Fuel Oil Only) 2.0370E-04 8.6725E-04 4 0.0009 lb/MWh

Total Metals (Updated, No. 6 Fuel Oil Only) 2.9952E-04 1.0774E-03 5 0.0011 lb/MWh

Total Metals (Updated, Inside Continental U.S.) 1.0375E-04 1.7195E-04 4 0.0002 lb/MWh

Total Metals (Updated, Outside Continental U.S.) 6.8068E-03 1.2517E-02 5 0.0125 lb/MWh

 

6

The data set only contains 42 data averages (see Table 13); therefore, the proposed Total Metals + Hg MACT floor for existing oil-fired units should have only included five 

emission averages instead of just seven. 

7

The data set only contains 42 data averages (see Table 13); therefore, the proposed Total Metals + Hg MACT floor for existing oil-fired units should have only included five 

emission averages instead of just seven. 
18

Table 12. New Total Metals MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Total Metals (Proposed, 3/16/11) 8.7194E-05 3.3099E-04 1 0.0004 lb/MWh

Total Metals (Updated) 8.7194E-05 3.3099E-04 1 0.00033 lb/MWh

Total Metals (Updated, No. 2 Fuel Oil Only) 9.9204E-05 2.6671E-04 1 0.00027 lb/MWh

Total Metals (Updated, No. 6 Fuel Oil Only) 8.7194E-05 3.3099E-04 1 0.00033 lb/MWh

Total Metals (Updated, Inside Continental U.S.) 8.7194E-05 3.3099E-04 1 0.00033 lb/MWh

Total Metals (Updated, Outside Continental U.S.) 5.0408E-03 6.2521E-03 1 0.00625 lb/MWh

Table 13. Number of Data Averages in Each Subcategory and Number of Units in Each Total Metals MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Total Metals (Updated) 42 (all data) 5

Total Metals (Updated, No. 2 Fuel Oil Only) 4 4

Total Metals (Updated, No. 6 Fuel Oil Only) 38 5

Total Metals (Updated, Inside Continental U.S.) 35 4

Total Metals (Updated, Outside Continental U.S.) 7 5
19

Non-Mercury Metals

Table 14. Existing Antimony (Sb) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Sb (Proposed, 3/16/11) 8.6708E-08 1.9652E-07 7 0.2 lb/TBtu

Sb (Updated) 8.6708E-08 1.9652E-07 7 0.20 lb/TBtu

Sb (Updated, No. 2 Fuel Oil Only) 7.8694E-08 2.2608E-07 5 0.23 lb/TBtu

Sb (Updated, No. 6 Fuel Oil Only) 4.3134E-07 1.2157E-06 6 1.22 lb/TBtu

Sb (Updated, Inside Continental U.S.) 7.5487E-08 2.0859E-07 5 0.21 lb/TBtu

Sb (Updated, Outside Continental U.S.) 5.9078E-07 1.3066E-06 5 1.31 lb/TBtu

Table 15. Existing Antimony (Sb) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Sb (Proposed, 3/16/11) 1.1052E-06 2.4682E-06 7 0.003 lb/GWh

Sb (Updated) 1.1052E-06 2.4682E-06 7 0.002 lb/GWh

Sb (Updated, No. 2 Fuel Oil Only) 1.0610E-06 2.9642E-06 5 0.003 lb/GWh

Sb (Updated, No. 6 Fuel Oil Only) 4.5100E-06 1.2627E-05 6 0.01 lb/GWh

Sb (Updated, Inside Continental U.S.) 9.7455E-07 2.6780E-06 5 0.003 lb/GWh

Sb (Updated, Outside Continental U.S.) 6.1239E-06 1.2681E-05 5 0.01 lb/GWh
20

Table 16. New Antimony (Sb) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Sb (Proposed, 3/16/11) 3.1152E-07 1.0740E-06 1 0.002 lb/GWh

Sb (Updated) 3.0233E-07 1.0423E-06 1 0.001 lb/GWh

Sb (Updated, No. 2 Fuel Oil Only) 3.0233E-07 1.0423E-06 1 0.001 lb/GWh

Sb (Updated, No. 6 Fuel Oil Only) 9.9974E-07 6.5591E-06 1 0.01 lb/GWh

Sb (Updated, Inside Continental U.S.) 3.0233E-07 1.0423E-06 1 0.001 lb/GWh

Sb (Updated, Outside Continental U.S.) 4.6207E-06 7.7015E-06 1 0.01 lb/GWh

Table 17. Number of Data Averages in Each Subcategory and Number of Units in Each Antimony (Sb) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Sb (Updated) 58 (all data) 7

Sb (Updated, No. 2 Fuel Oil Only) 6 5

Sb (Updated, No. 6 Fuel Oil Only) 52 6

Sb (Updated, Inside Continental U.S.) 43 5

Sb (Updated, Outside Continental U.S.) 15 5
21

Table 18. Existing Arsenic (As) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of

sources in 

the floor

Floor value Units

As (Proposed, 3/16/11) 2.7023E-07 5.4091E-07 7 0.6 lb/TBtu

As (Updated) 2.7023E-07 5.4091E-07 7 0.54 lb/TBtu

As (Updated, No. 2 Fuel Oil Only) 6.0625E-07 2.4786E-06 5 2.48 lb/TBtu

As (Updated, No. 6 Fuel Oil Only) 3.8533E-07 1.1458E-06 6 1.15 lb/TBtu

As (Updated, Inside Continental U.S.) 2.3288E-07 4.7926E-07 5 0.48 lb/TBtu

As (Updated, Outside Continental U.S.) 2.8634E-06 3.9554E-06 5 3.96 lb/TBtu

Table 19. Existing Arsenic (As) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

As (Proposed, 3/16/11) 3.2301E-06 6.8826E-06 7 0.007 lb/GWh

As (Updated) 3.2301E-06 6.8826E-06 7 0.007 lb/GWh

As (Updated, No. 2 Fuel Oil Only) 7.7817E-06 3.0341E-05 5 0.03 lb/GWh

As (Updated, No. 6 Fuel Oil Only) 3.9555E-06 1.1480E-05 6 0.01 lb/GWh

As (Updated, Inside Continental U.S.) 2.7544E-06 6.1604E-06 5 0.006 lb/GWh

As (Updated, Outside Continental U.S.) 2.8726E-05 3.8322E-05 5 0.04 lb/GWh
22

Table 20. New Arsenic (As) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

As (Proposed, 3/16/11) 1.4986E-06 1.5529E-06 1 0.002 lb/GWh

As (Updated) 1.6590E-06 1.7190E-06 1 0.002 lb/GWh

As (Updated, No. 2 Fuel Oil Only) 3.1052E-06 1.2174E-05 1 0.01 lb/GWh

As (Updated, No. 6 Fuel Oil Only) 1.6590E-06 1.7190E-06 1 0.002 lb/GWh

As (Updated, Inside Continental U.S.) 1.6590E-06 1.7190E-06 1 0.002 lb/GWh

As (Updated, Outside Continental U.S.) 2.5646E-05 6.9465E-05 1 0.07 lb/GWh

Table 21. Number of Data Averages in Each Subcategory and Number of Units in Each Arsenic (As) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

As (Updated) 59 (all data) 7

As (Updated, No. 2 Fuel Oil Only) 6 5

As (Updated, No. 6 Fuel Oil Only) 53 6

As (Updated, Inside Continental U.S.) 45 5

As (Updated, Outside Continental U.S.) 14 5
23

Table 22. Existing Beryllium (Be) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Be (Proposed, 3/16/11) 2.7199E-08 5.6981E-08 7 0.06 lb/TBtu

Be (Updated) 3.0197E-08 6.4029E-08 7 0.06 lb/TBtu

Be (Updated, No. 2 Fuel Oil Only) 2.8429E-08 7.3418E-08 5 0.07 lb/TBtu

Be (Updated, No. 6 Fuel Oil Only) 4.3308E-08 7.3545E-08 6 0.07 lb/TBtu

Be (Updated, Inside Continental U.S.) 2.5382E-08 5.4599E-08 5 0.05 lb/TBtu

Be (Updated, Outside Continental U.S.) 1.3391E-07 4.1480E-07 5 0.41 lb/TBtu

Table 23. Existing Beryllium (Be) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Be (Proposed, 3/16/11) 3.2934E-07 6.2782E-07 7 0.0007 lb/GWh

Be (Updated) 3.6186E-07 6.8646E-07 7 0.0007 lb/GWh

Be (Updated, No. 2 Fuel Oil Only) 3.8370E-07 9.3304E-07 5 0.001 lb/GWh

Be (Updated, No. 6 Fuel Oil Only) 4.5301E-07 7.9249E-07 6 0.001 lb/GWh

Be (Updated, Inside Continental U.S.) 3.1961E-07 6.4112E-07 5 0.001 lb/GWh

Be (Updated, Outside Continental U.S.) 1.3316E-06 3.8244E-06 5 0.004 lb/GWh
24

Table 24. New Beryllium (Be) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Be (Proposed, 3/16/11) 2.2836E-07 6.7882E-07 1 0.0007 lb/GWh

Be (Updated) 2.2836E-07 6.7882E-07 1 0.0007 lb/GWh

Be (Updated, No. 2 Fuel Oil Only) 2.2836E-07 6.7882E-07 1 0.0007 lb/GWh

Be (Updated, No. 6 Fuel Oil Only) 2.8769E-07 8.5966E-07 1 0.001 lb/GWh

Be (Updated, Inside Continental U.S.) 2.2836E-07 6.7882E-07 1 0.0007 lb/GWh

Be (Updated, Outside Continental U.S.) 7.7019E-07 2.2522E-06 1 0.002 lb/GWh

Table 25. Number of Data Averages in Each Subcategory and Number of Units in Each Beryllium (Be) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Be (Updated) 59 (all data) 7

Be (Updated, No. 2 Fuel Oil Only) 6 5

Be (Updated, No. 6 Fuel Oil Only) 53 6

Be (Updated, Inside Continental U.S.) 45 5

Be (Updated, Outside Continental U.S.) 14 5
25

Table 26. Existing Cadmium (Cd) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Cd (Proposed, 3/16/11) 4.3958E-08 9.2940E-08 7 0.1 lb/TBtu

Cd (Updated) 4.3958E-08 9.2940E-08 7 0.09 lb/TBtu

Cd (Updated, No. 2 Fuel Oil Only) 9.0057E-08 3.9523E-07 5 0.40 lb/TBtu

Cd (Updated, No. 6 Fuel Oil Only) 4.6710E-08 1.1054E-07 6 0.11 lb/TBtu

Cd (Updated, Inside Continental U.S.) 3.9378E-08 1.0123E-07 5 0.10 lb/TBtu

Cd (Updated, Outside Continental U.S.) 8.9237E-08 1.8774E-07 5 0.19 lb/TBtu

Table 27. Existing Cadmium (Cd) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Cd (Proposed, 3/16/11) 4.8715E-07 1.0240E-06 7 0.002 lb/GWh

Cd (Updated) 4.8534E-07 1.0167E-06 7 0.001 lb/GWh

Cd (Updated, No. 2 Fuel Oil Only) 1.2120E-06 5.4326E-06 5 0.005 lb/GWh

Cd (Updated, No. 6 Fuel Oil Only) 4.7749E-07 1.1018E-06 6 0.00 lb/GWh

Cd (Updated, Inside Continental U.S.) 4.3667E-07 1.1130E-06 5 0.001 lb/GWh

Cd (Updated, Outside Continental U.S.) 8.8216E-07 1.8769E-06 5 0.002 lb/GWh
26

Table 28. New Cadmium (Cd) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Cd (Proposed, 3/16/11) 1.2994E-07 3.8828E-07 1 0.0004 lb/GWh

Cd (Updated) 1.2994E-07 3.8828E-07 1 0.0004 lb/GWh

Cd (Updated, No. 2 Fuel Oil Only) 5.3245E-07 2.2762E-06 1 0.002 lb/GWh

Cd (Updated, No. 6 Fuel Oil Only) 1.2994E-07 3.8828E-07 1 0.0004 lb/GWh

Cd (Updated, Inside Continental U.S.) 1.2994E-07 3.8828E-07 1 0.0004 lb/GWh

Cd (Updated, Outside Continental U.S.) 6.0290E-07 1.0847E-06 1 0.001 lb/GWh

Table 29. Number of Data Averages in Each Subcategory and Number of Units in Each Cadmium (Cd) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Cd (Updated) 60 (all data) 7

Cd (Updated, No. 2 Fuel Oil Only) 6 5

Cd (Updated, No. 6 Fuel Oil Only) 54 6

Cd (Updated, Inside Continental U.S.) 45 5

Cd (Updated, Outside Continental U.S.) 15 5
27

Table 30. Existing Cobalt (Co) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Co (Proposed, 3/16/11) 5.8610E-07 2.0215E-06 7

8

3 lb/TBtu

Co (Updated) 3.9971E-07 1.8317E-06 5 1.83 lb/TBtu

Co (Updated, No. 2 Fuel Oil Only) 2.0418E-06 1.9250E-05 5 19.25 lb/TBtu

Co (Updated, No. 6 Fuel Oil Only) 9.9346E-07 2.7461E-06 5 2.75 lb/TBtu

Co (Updated, Inside Continental U.S.) 2.5284E-07 9.4275E-07 4 0.94 lb/TBtu

Co (Updated, Outside Continental U.S.) 2.5696E-05 5.0270E-05 5 50.27 lb/TBtu

Table 31. Existing Cobalt (Co) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Co (Proposed, 3/16/11) 6.1582E-06 1.9352E-05 7

9

0.02 lb/GWh

Co (Updated) 4.4948E-06 1.8090E-05 5 0.018 lb/GWh

Co (Updated, No. 2 Fuel Oil Only) 2.9010E-05 2.7427E-04 5 0.274 lb/GWh

Co (Updated, No. 6 Fuel Oil Only) 9.6700E-06 2.5926E-05 5 0.03 lb/GWh

Co (Updated, Inside Continental U.S.) 3.1618E-06 1.1629E-05 4 0.012 lb/GWh

Co (Updated, Outside Continental U.S.) 2.7479E-04 5.0567E-04 5 0.51 lb/GWh

 

8

The data set only contains 44 data averages (see Table 33); therefore, the proposed cobalt MACT floor for existing oil-fired units should have only included five emission 

averages instead of just seven. 

9

The data set only contains 44 data averages (see Table 33); therefore, the proposed cobalt MACT floor for existing oil-fired units should have only included five emission 

averages instead of just seven. 
28

Table 32. New Cobalt (Co) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Co (Proposed, 3/16/11) 1.1416E-06 5.7337E-06 1 0.02 lb/GWh

Co (Updated) 1.1416E-06 5.7337E-06 1 0.006 lb/GWh

Co (Updated, No. 2 Fuel Oil Only) 1.1416E-06 5.7337E-06 1 0.006 lb/GWh

Co (Updated, No. 6 Fuel Oil Only) 3.4404E-06 2.0932E-05 1 0.021 lb/GWh

Co (Updated, Inside Continental U.S.) 1.1416E-06 5.7337E-06 1 0.006 lb/GWh

Co (Updated, Outside Continental U.S.) 1.9888E-04 2.5213E-04 1 0.25 lb/GWh

Table 33. Number of Data Averages in Each Subcategory and Number of Units in Each Cobalt (Co) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Co (Updated) 44 (all data) 5

Co (Updated, No. 2 Fuel Oil Only) 4 5

Co (Updated, No. 6 Fuel Oil Only) 40 5

Co (Updated, Inside Continental U.S.) 37 4

Co (Updated, Outside Continental U.S.) 7 5
29

Table 34. Existing Chromium (Cr) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Cr (Proposed, 3/16/11) 7.8696E-07 1.5677E-06 7 2 lb/TBtu

Cr (Updated) 7.8696E-07 1.5677E-06 7 1.6 lb/TBtu

Cr (Updated, No. 2 Fuel Oil Only) 1.4164E-06 4.9444E-06 5 4.94 lb/TBtu

Cr (Updated, No. 6 Fuel Oil Only) 9.8380E-07 2.3867E-06 6 2.39 lb/TBtu

Cr (Updated, Inside Continental U.S.) 7.3324E-07 1.7877E-06 5 1.79 lb/TBtu

Cr (Updated, Outside Continental U.S.) 1.9744E-06 5.1772E-06 5 5.18 lb/TBtu

Table 35. Existing Chromium (Cr) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Cr (Proposed, 3/16/11) 8.9730E-06 1.8550E-05 7 0.02 lb/GWh

Cr (Updated) 8.9730E-06 1.8550E-05 7 0.019 lb/GWh

Cr (Updated, No. 2 Fuel Oil Only) 1.9224E-05 7.0424E-05 5 0.070 lb/GWh

Cr (Updated, No. 6 Fuel Oil Only) 1.1160E-05 3.1241E-05 6 0.03 lb/GWh

Cr (Updated, Inside Continental U.S.) 8.2181E-06 2.0241E-05 5 0.020 lb/GWh

Cr (Updated, Outside Continental U.S.) 2.0497E-05 5.1813E-05 5 0.05 lb/GWh
30

Table 36. New Chromium (Cr) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Cr (Proposed, 3/16/11) 3.9709E-06 1.1692E-05 1 0.02 lb/GWh

Cr (Updated) 4.3637E-06 1.2849E-05 1 0.013 lb/GWh

Cr (Updated, No. 2 Fuel Oil Only) 6.8809E-06 3.6806E-05 1 0.037 lb/GWh

Cr (Updated, No. 6 Fuel Oil Only) 4.3637E-06 1.2849E-05 1 0.013 lb/GWh

Cr (Updated, Inside Continental U.S.) 4.3637E-06 1.2849E-05 1 0.013 lb/GWh

Cr (Updated, Outside Continental U.S.) 9.3654E-06 1.2084E-05 1 0.012 lb/GWh

Table 37. Number of Data Averages in Each Subcategory and Number of Units in Each Chromium (Cr) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Cr (Updated) 60 (all data) 7

Cr (Updated, No. 2 Fuel Oil Only) 6 5

Cr (Updated, No. 6 Fuel Oil Only) 54 6

Cr (Updated, Inside Continental U.S.) 45 5

Cr (Updated, Outside Continental U.S.) 15 5
31

Table 38. Existing Lead (Pb) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Pb (Proposed, 3/16/11) 6.4748E-07 1.9103E-06 7 2 lb/TBtu

Pb (Updated) 6.4748E-07 1.9103E-06 7 1.91 lb/TBtu

Pb (Updated, No. 2 Fuel Oil Only) 3.6861E-06 1.5931E-05 5 15.93 lb/TBtu

Pb (Updated, No. 6 Fuel Oil Only) 7.5350E-07 2.4657E-06 6 2.47 lb/TBtu

Pb (Updated, Inside Continental U.S.) 5.6323E-07 2.2959E-06 5 2.30 lb/TBtu

Pb (Updated, Outside Continental U.S.) 1.2505E-06 2.9406E-06 5 2.94 lb/TBtu

Table 39. Existing Lead (Pb) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Pb (Proposed, 3/16/11) 7.2271E-06 2.0418E-05 7 0.03 lb/GWh

Pb (Updated) 7.2271E-06 2.0418E-05 7 0.02 lb/GWh

Pb (Updated, No. 2 Fuel Oil Only) 4.9808E-05 2.1064E-04 5 0.211 lb/GWh

Pb (Updated, No. 6 Fuel Oil Only) 7.8624E-06 2.6019E-05 6 0.026 lb/GWh

Pb (Updated, Inside Continental U.S.) 6.4819E-06 2.4811E-05 5 0.025 lb/GWh

Pb (Updated, Outside Continental U.S.) 1.2794E-05 2.8317E-05 5 0.03 lb/GWh
32

Table 40. New Lead (Pb) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Pb (Proposed, 3/16/11) 1.2618E-06 5.3277E-06 1 0.006 lb/GWh

Pb (Updated) 1.3867E-06 5.8548E-06 1 0.006 lb/GWh

Pb (Updated, No. 2 Fuel Oil Only) 7.4773E-06 2.2520E-05 1 0.023 lb/GWh

Pb (Updated, No. 6 Fuel Oil Only) 1.3867E-06 5.8548E-06 1 0.006 lb/GWh

Pb (Updated, Inside Continental U.S.) 1.3867E-06 5.8548E-06 1 0.006 lb/GWh

Pb (Updated, Outside Continental U.S.) 7.8624E-06 2.3734E-05 1 0.024 lb/GWh

Table 41. Number of Data Averages in Each Subcategory and Number of Units in Each Lead (Pb) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Pb (Updated) 60 (all data) 7

Pb (Updated, No. 2 Fuel Oil Only) 6 5

Pb (Updated, No. 6 Fuel Oil Only) 54 6

Pb (Updated, Inside Continental U.S.) 45 5

Pb (Updated, Outside Continental U.S.) 15 5
33

Table 42. Existing Manganese (Mn) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Mn (Proposed, 3/16/11) 1.4568E-06 4.3093E-06 7 5 lb/TBtu

Mn (Updated) 1.4568E-06 4.3093E-06 7 4.31 lb/TBtu

Mn (Updated, No. 2 Fuel Oil Only) 1.7673E-06 5.0708E-06 5 5.07 lb/TBtu

Mn (Updated, No. 6 Fuel Oil Only) 3.7452E-06 1.2719E-05 6 12.72 lb/TBtu

Mn (Updated, Inside Continental U.S.) 1.0346E-06 2.8039E-06 5 2.80 lb/TBtu

Mn (Updated, Outside Continental U.S.) 9.4323E-06 1.9942E-05 5 19.94 lb/TBtu

Table 43. Existing Manganese (Mn) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Mn (Proposed, 3/16/11) 1.8763E-05 5.9894E-05 7 0.06 lb/GWh

Mn (Updated) 1.8763E-05 5.9894E-05 7 0.06 lb/GWh

Mn (Updated, No. 2 Fuel Oil Only) 2.3512E-05 6.9395E-05 5 0.07 lb/GWh

Mn (Updated, No. 6 Fuel Oil Only) 3.8913E-05 1.3287E-04 6 0.13 lb/GWh

Mn (Updated, Inside Continental U.S.) 1.2565E-05 3.6932E-05 5 0.04 lb/GWh

Mn (Updated, Outside Continental U.S.) 9.8582E-05 2.1457E-04 5 0.21 lb/GWh
34

Table 44. New Manganese (Mn) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Mn (Proposed, 3/16/11) 4.8608E-06 2.4490E-05 1 0.03 lb/GWh

Mn (Updated) 5.3417E-06 2.6912E-05 1 0.03 lb/GWh

Mn (Updated, No. 2 Fuel Oil Only) 1.1962E-05 4.5895E-05 1 0.05 lb/GWh

Mn (Updated, No. 6 Fuel Oil Only) 5.3417E-06 2.6912E-05 1 0.03 lb/GWh

Mn (Updated, Inside Continental U.S.) 5.3417E-06 2.6912E-05 1 0.03 lb/GWh

Mn (Updated, Outside Continental U.S.) 6.7081E-05 9.3682E-05 1 0.09 lb/GWh

Table 45. Number of Data Averages in Each Subcategory and Number of Units in Each Manganese (Mn) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Mn (Updated) 59 (all data) 7

Mn (Updated, No. 2 Fuel Oil Only) 6 5

Mn (Updated, No. 6 Fuel Oil Only) 53 6

Mn (Updated, Inside Continental U.S.) 44 5

Mn (Updated, Outside Continental U.S.) 15 5
35

Table 46. Existing Nickel (Ni) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Nickel (Proposed, 3/16/11) 2.3887E-06 7.2536E-06 7 8.00 lb/TBtu

Nickel (Updated) 2.3887E-06 7.2536E-06 7 7.25 lb/TBtu

Nickel (Updated, No. 2 Fuel Oil Only) 1.7195E-06 5.5413E-06 5 5.54 lb/TBtu

Nickel (Updated, No. 6 Fuel Oil Only) 1.5940E-05 5.0079E-05 6 50.08 lb/TBtu

Nickel (Updated, Inside Continental U.S.) 1.7195E-06 5.5413E-06 5 5.54 lb/TBtu

Nickel (Updated, Outside Continental U.S.) 4.2402E-04 5.2232E-04 5 522.32 lb/TBtu

Table 47. Existing Nickel (Ni) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Nickel (Proposed, 3/16/11) 2.8419E-05 7.8157E-05 7 0.08 lb/GWh

Nickel (Updated) 2.8419E-05 7.8157E-05 7 0.078 lb/GWh

Nickel (Updated, No. 2 Fuel Oil Only) 2.3335E-05 7.8849E-05 5 0.079 lb/GWh

Nickel (Updated, No. 6 Fuel Oil Only) 1.6172E-04 5.1256E-04 6 0.51 lb/GWh

Nickel (Updated, Inside Continental U.S.) 2.1876E-05 6.8953E-05 5 0.069 lb/GWh

Nickel (Updated, Outside Continental U.S.) 4.0618E-03 6.1361E-03 5 6.14 lb/GWh
36

Table 48. New Nickel (Ni) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in

the floor

Floor value Units

Nickel (Proposed, 3/16/11) 1.1470E-05 3.7526E-05 1 0.04 lb/GWh

Nickel (Updated) 1.1132E-05 3.6419E-05 1 0.04 lb/GWh

Nickel (Updated, No. 2 Fuel Oil Only) 1.1132E-05 3.6419E-05 1 0.04 lb/GWh

Nickel (Updated, No. 6 Fuel Oil Only) 3.3038E-05 2.0944E-04 1 0.21 lb/GWh

Nickel (Updated, Inside Continental U.S.) 1.1132E-05 3.6419E-05 1 0.04 lb/GWh

Nickel (Updated, Outside Continental U.S.) 3.5205E-03 7.4115E-03 1 7.4 lb/GWh

Table 49. Number of Data Averages in Each Subcategory and Number of Units in Each Nickel (Ni) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Nickel (Updated) 60 (all data) 7

Nickel (Updated, No. 2 Fuel Oil Only) 6 5

Nickel (Updated, No. 6 Fuel Oil Only) 54 6

Nickel (Updated, Inside Continental U.S.) 45 5

Nickel (Updated, Outside Continental U.S.) 15 5
37

Table 50. Existing Selenium (Se) MACT Floors for Oil-Fired Units (Input Based Standard)

Pollutant Mean (lb/MMBtu) UPL (lb/MMBtu)

Number of 

sources in 

the floor

Floor value Units

Se (Proposed, 3/16/11) 5.0320E-07 1.0922E-06 7 2 lb/TBtu

Se (Updated) 5.0320E-07 1.0922E-06 7 1.09 lb/TBtu

Se (Updated, No. 2 Fuel Oil Only) 5.1970E-07 1.3698E-06 5 1.37 lb/TBtu

Se (Updated, No. 6 Fuel Oil Only) 7.1192E-07 1.4734E-06 6 1.47 lb/TBtu

Se (Updated, Inside Continental U.S.) 4.3962E-07 1.1212E-06 5 1.12 lb/TBtu

Se (Updated, Outside Continental U.S.) 1.1564E-06 2.1122E-06 5 2.11 lb/TBtu

Table 51. Existing Selenium (Se) MACT Floors for Oil-Fired Units (alternate Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Se (Proposed, 3/16/11) 6.1244E-06 1.3004E-05 7 0.02 lb/GWh

Se (Updated) 6.1244E-06 1.3004E-05 7 0.013 lb/GWh

Se (Updated, No. 2 Fuel Oil Only) 6.8780E-06 1.7632E-05 5 0.018 lb/GWh

Se (Updated, No. 6 Fuel Oil Only) 7.5148E-06 1.4973E-05 6 0.015 lb/GWh

Se (Updated, Inside Continental U.S.) 5.4858E-06 1.4199E-05 5 0.014 lb/GWh

Se (Updated, Outside Continental U.S.) 1.1661E-05 2.0950E-05 5 0.021 lb/GWh
38

Table 52. New Selenium (Se) MACT Floors for Oil-Fired Units (Output-Based Standard)

Pollutant Mean (lb/MW) UPL (lb/MW)

Number of 

sources in 

the floor

Floor value Units

Se (Proposed, 3/16/11) 2.5693E-06 3.8753E-06 1 0.004 lb/GWh

Se (Updated) 2.5693E-06 3.8753E-06 1 0.004 lb/GWh

Se (Updated, No. 2 Fuel Oil Only) 2.5693E-06 3.8753E-06 1 0.004 lb/GWh

Se (Updated, No. 6 Fuel Oil Only) 4.0341E-06 1.4859E-05 1 0.015 lb/GWh

Se (Updated, Inside Continental U.S.) 2.5693E-06 3.8753E-06 1 0.004 lb/GWh

Se (Updated, Outside Continental U.S.) 7.6945E-06 1.7693E-05 1 0.018 lb/GWh

Table 53. Number of Data Averages in Each Subcategory and Number of Units in Each Selenium (Se) MACT Floor for Oil-Fired Units Floor

Pollutant Number of sources 

in subcategory

Number of 

sources in the 

floor

Se (Updated) 60 (all data) 7

Se (Updated, No. 2 Fuel Oil Only) 6 5

Se (Updated, No. 6 Fuel Oil Only) 54 6

Se (Updated, Inside Continental U.S.) 45 5

Se (Updated, Outside Continental U.S.) 15 5
39

Appendix A

Discussion on Fate of Mercury 

During Distillation of Crude Oil
40

With regard to crude oil sources in the world-wide market and the variability of mercury content 

in grades of fuel oil, Wilhelm10 states the fate of mercury during distillation of crude oil depends 

on several factors:

“...Crude oil contains both dissolved and suspended mercury compounds. A typical 

analysis for total mercury in crude oil yields the sum of both forms, but the suspended 

amount is not necessarily reflective of the reservoir concentration. The sampling and 

analytical protocols for differentiation of the various forms of mercury in hydrocarbon 

liquids have been only recently applied, but the variations seen in THg [total mercury]

from particular fields are due more to variation in the suspended fraction as opposed to 

the truly dissolved fraction.

For example, order of magnitude differences in total mercury concentration can be 

obtained for the same crude oil between samples taken upstream and downstream of 

separators and desalters. Crude oil sampled from tankers typically comes from the top of 

the tank where suspended forms can be lower in concentration due to settling in transit”.

Wilhelm also states that “[t]he fates of dissolved and suspended forms of mercury in the refining 

process ... are different. The suspended forms (mostly HgS) are nonvolatile and tend to remain in 

the residuum in the primary and vacuum distillations. Dissolved forms (mostly Hg0) are volatile 

and are more likely to transfer to lighter products. Organic forms, if present, may be converted to 

Hg0 by hydrotreating.”

 

10 S. Mark Wilhelm, Estimate of Mercury Emissions to the Atmosphere from Petroleum. Environmental Science and 

Technology, Vol. 35, No. 24, 2001. American Chemical Society.