1400 K Street, NW  Washington, DC 20005  tel (202) 682-4800  fax (202) 682-4854  www.rma.org 

 

July 15, 2011 

Mr. Brian Shrager 

Energy Strategies Group 

Sector Policies and Programs Division 

Office of Air Quality Planning and Standards (D243-01) 

U.S. Environmental Protection Agency 

Research Triangle Park, NC 27711 

Re: Liquid Fuel Data - “National Emission Standards for Hazardous Air Pollutants for Major 

Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters” 

Docket ID EPA-HQ-OAR-2002-0058 

Mr. Shrager: 

The Rubber Manufacturers Association (“RMA”)1

 appreciates the opportunity to provide this 

additional information related to the Liquid Fuel subcategory in the National Emission Standards 

for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional 

Boilers and Process Heaters (Boiler MACT). We are concerned with the data and methodology 

EPA used to establish the emission limits for liquid fuel boilers and believe that further analysis 

and quality assurance of the data and improvements to the floor setting methodologies are 

needed. 

We agree with EPA’s approach of assigning a fuel variability factor to the HCl and Hg data to 

improve the consideration of variability in setting the floor, but EPA should gather additional 

data to improve the representativeness of the floor units. EPA should gather additional 

emissions information to ensure the final limits are achievable by boilers and process heaters 

burning liquids other than distillate oil and should not use data from boilers burning site-specific 

process liquids that may or may not be classified as fuels and are not representative of the 

hundreds of fuel oil-fired boilers that make up the liquid subcategory (e.g., the Milliken boiler 

that has been classified as a top performer and is burning “anhydrides waste”). 

1

 The Rubber Manufacturers Association is the national trade association representing 

every major domestic tire manufacturer including: Bridgestone Americas, Inc.; Continental Tire 

the Americas, LLC; Cooper Tire & Rubber Company; The Goodyear Tire & Rubber Company; 

Michelin North America, Inc.; Pirelli North America; Toyo Tire (U.S.A.) Corporation and 

Yokohama Tire Corporation. 
Rubber Manufacturers Association 

July 15, 2011 

Page 2 

 

EPA Should Re-Examine its Floor Setting Process for Liquid Fuel Boilers for CO 

EPA has grouped all boilers and process heaters firing any liquid fuel into one subcategory. 

Comments on the proposed rule suggested further subcategorization into heavy and light liquids. 

This further subcategorization was not incorporated into the final rule. In the response to 

comments, EPA states that although there are design differences between heavy and light liquid 

fired units, the approach taken in the final rule is consistent with that for solid fuels, as all solid 

fuels are grouped together for the fuel based HAP. EPA goes on to say that although solid fuel 

units are split for CO and dioxin/furan, they are not splitting light and heavy liquid units and the 

floors are made up of a mix of light and heavy units.2

 The CO limits that EPA has finalized are 

made up of 3-run stack test data that EPA has largely adjusted due to measurement capabilities 

of EPA Method 10, with little variability as a result. The floor units represent only 2 facilities, 

both burning distillate fuel oil. An analysis of the CO data for heavy and light liquid units 

indicates that a very different CO limit would result for heavy liquid units when these units are 

treated as separate subcategories. This would indicate that EPA should be consistent with the 

Agency’s treatment of fuel and design based subcategories by establishing separate CO emission 

limits for heavy and light liquid units. 

At a minimum, as EPA has acknowledged the variable nature of CO emissions, additional data 

should be gathered to ensure achievability of the established limit, rather than using short term 

data from boilers at only 2 facilities. We would also like to point out that the NJMerckRahway 

floor boilers using a CO/VOC catalyst (which EPA has said is the appropriate control technology 

to reduce boiler CO/organic HAP emissions) have CO emissions higher than the 

NJMerckRahway floor boilers that are not using a CO/VOC catalyst. 

EPA Should Examine the PM Emissions Data and Discard Data Below the Limits of 

Quantitation 

The liquid PM limits are set using a very small amount of data, and are not representative of 

fabric filter control technology (which EPA states is the technology assumed to be MACT for 

PM), as none of the floor units have controls. There are only 18 data points used to set the PM 

floor, one of which is labeled as detection level limited (DLL). Therefore, the “top performers” 

are determined based on a very limited data set and reflect only combustion of distillate fuel oil 

or “anhydrides waste”. In fact, no unit burning No. 6 fuel oil (even the one listed as having a 

fabric filter with sorbent injection) meets the liquid fuel PM limit based on the PM stack test and 

fuel firing information in the EPA database. 

Published studies indicate that the practical quantitation limit of Method 5 is 3 to 6 mg, and a 

1996 EPA-funded study indicated that the minimum PM catch for ±10 percent accuracy of 

Method 5 is 7.2 mg3

. The 1996 study examined the level of random errors present in the test 

method and sought to determine what level of particulate must be captured in order to overcome 

the influence of that random error on the reported results. The results of the study documented 

that in order to have a 90% confidence in the accuracy of particulate matter emissions, the 

2

 Response to commenter EPA-HQ-OAR-2002-0058-1869.1, Comment Excerpt Number 4. 

3

 “Minimum Detection Limit for Method 5,” R. Shigehara, Entropy Incorporated, EPA Contract 

No. 68-D2-0163, Work Assignment 3-06, September 30, 1996. 
Rubber Manufacturers Association 

July 15, 2011 

Page 3 

minimum catch of residue must be > 7.2 mg. Examination of the test data reported for every unit 

in the liquid floor and several units just outside of the liquid floor indicate that two or more of 

the test runs for each unit captured less than 7.2 mg of total particulate residue during the test run. 

Based on this study, these units could be top performers solely due to random error in the test 

method. Setting an emissions standard for particulate matter using data that contains this level of 

uncertainty is both unlawful and scientifically flawed. We request that EPA reconsider the use 

of such data in setting the particulate matter emissions standard. 

EPA Should Re-Assess the Mercury Limit for Liquid Units 

There are 79 liquid-fired units for which EPA has gathered Hg data, but only 8 stack tests. 71 

units are assigned fuel analysis data, but these data represent only 14 facilities. There are 

11 floor units, with 50 data points, of which only 10 (2 stack tests and 2 fuel analyses) are 

labeled as above the detection limit. This is a very limited amount of data and a very biased data 

set (primarily based on non-detect data) to be used to set Hg limits for units firing any type of 

liquid fuel. The Hg limits are again based on units with no Hg controls, but on the fuels with the 

lowest amounts of mercury. EPA has considered fuel variability for the units with paired fuel 

analysis/stack test data, but should also examine the variability of the fuel analysis data for the 

other units in the floor (e.g., use the ratio of the 99th percentile fuel Hg content to the average 

fuel Hg content). EPA should not discard certain fuel analysis data as “outliers” if investigation 

reveals that the data are of good quality (e.g., values that can be determined to be “real” when 

compared to other fuel analysis data that are available to EPA in the database). 

We offer the following data quality observations with respect to two test reports for the units in 

the Hg liquid floor: 

 MNGPDuluth – EU33 Boiler #3: The data in the test report was examined and found to 

have errors in calculating emissions of mercury. The test company did not include all of 

the non-detect fraction levels in the sum of mass from the analytical report. We have 

recalculated the results using the full detection limits from the analytical report for all 

sample fractions and determined the results of the testing should have been reported as: 

Run 1 [<1.425E-07] 

Run 2 [<1.424E-07] 

Run 3 [<1.618E-07] 

Average [<1.489E-07] 

 NYConEd59thStStationNewYork – Boiler 118: In examination of the test report we 

have discovered that the analytical laboratory failed to analyzed all five fractions of the 

EPA Method 29 samples only providing results for fractions 5b and 5c thus not reporting 

all of the mercury collected by the test method. This test data in incomplete and should 

be invalidated and removed from the data set. 

EPA Should Re-Assess the HCl Limit for Liquid Units 

The HCl floors are similarly developed with a small amount of data and are based in large part 

on non-detect data (only 5 of 35 data points used to set the floor are above the detection limit – 1 

stack test and 1 set of fuel analysis data). For PABoeingRidleyPark Units 035, CB4, 031, 036, 

037, 039, and 053, the floor data are based on fuel analysis collected during testing on Unit 033 

at that facility. In examination of the analytical data for those fuel samples, it is apparent that the 
Rubber Manufacturers Association 

July 15, 2011 

Page 4 

 

Fuel Analysis Spreadsheet supplied to EPA incorrectly indicated the units of measure as mg/kg. 

The true analytical results on the report were measured in %. This makes the reported emissions 

from each of the seven units off by a factor of 10,000. Results should have been calculated as 

5.53E-03 lb/mmBtu, which thereby removes all of these units from the floor. 

EPA has considered fuel variability for the units with paired fuel analysis/stack test data, but 

should also examine the variability of the fuel analysis data for the other units in the floor (e.g., 

use the ratio of the 99th percentile fuel chloride content to the average fuel chloride content). 

EPA should not discard certain fuel analysis data as “outliers” if investigation reveals that the 

data are of good quality (e.g., values that can be determined to be “real” when compared to other 

fuel analysis data that are available to EPA in the database). 

The selected top performing unit (TNInvistaChattanooga EU003 Vaporizer #2) emission test 

data show higher emissions than the limit set for existing liquid fired units (0.00062 lb/MMBtu 

for this unit versus the existing unit limit of 0.00033 lb/MMBtu). Only the lower test data were 

used in the floor setting calculations for some reason. This seems to indicate a problem with 

EPA’s floor setting methodology; the selected top performer should be able to meet the 

established limit. 

EPA Should Not Set Numeric Dioxin/Furan Emission Standards 

Work practice standards and not emission limits are warranted for dioxin/furan under Boiler 

MACT. 

 The data collected in order to set the D/F standards for liquid fuel-fired industrial boilers 

are at levels below the capability of the analytical and stack test methods to detect 

emissions of these compounds. Much of the test data are labeled as being below the 

method detection limit and the remainder of the data are often flagged as being below the 

level the laboratory feels can be reported with confidence. 

 It is not appropriate to treat detection level limited data in the same manner as detected 

values for purposes of establishing regulatory limits because the uncertainty4 associated 

with measurements near or below the method detection limits is too high. The test 

methods were developed over 30 years ago to measure D/F at concentrations then found 

in some types of waste incinerator exhaust (levels orders of magnitude higher than those 

found in exhaust from today’s industrial boilers). 

 All source emission measurements have random (precision) errors associated with the 

sample collection, sample and equipment handling, sample preparation, and sample 

analysis. When emission levels are much higher than the magnitude of these errors, there 

is a high degree of confidence in the measured value obtained from a single or a few test 

runs. However, as the measured value decreases, the contribution of these errors to the 

measured value increases, thus decreasing the confidence level in the accuracy of the 

measured value from a single or a few runs until the point where the measured value 

cannot be distinguished from the random error (“noise” level). This is the case with the 

4

 Uncertainty here refers to the statistical expression of measurement error, such as defined in 

ASME Performance Test Code 19.1, rather than an inference of something which is unknown.
Rubber Manufacturers Association 

July 15, 2011 

Page 5 

 

boiler D/F data. When this occurs, the measurement cannot be distinguished from zero 

with high confidence. 

 In setting the Boiler MACT and CISWI standards, EPA has acknowledged that the 

emission limit should not be set below the capability of the applicable test method. 

However, EPA did not use the widely accepted definition of method detection limit, 

which is based on the capabilities of multiple commercial laboratories to analyze a 

sample and identify the presence of a chemical above the “noise” level. In its place, EPA 

coined a new term, representative method detection limit (RDL) to define a measurement 

method detection limit which is based on the laboratory detection limits reported for the 

tests with the lowest emissions. This erroneous methodology resulted in estimating D/F 

detection limits that are over 100 times lower than those regularly achieved by 

commercial laboratories. 

 The detection limit of an analytical method is commonly defined as the lowest 

concentration that can be distinguished from replicate blanks. The quantitation limit of a 

method is defined as the smallest concentration of the substance which can be measured 

with an acceptable level of uncertainty. Detection limits and quantitation limits are 

defined in a scientific, non-arbitrary manner in various widely-published peer-reviewed 

consensus guidelines5 and EPA documents. Quantitation limits of test methods have 

great significance when measuring very low concentrations of pollutants. In practice, 

reported values below the method's quantification limit should not be treated as real 

values. 

 As demonstrated by the measurement issues noted, quantifying the actual, extremely low 

or non-existent dioxin emission levels for the Boiler MACT floor units is technologically 

impracticable, and thus, it is not feasible to prescribe or enforce an emission standard for 

D/F emissions for these units. Clean Air Act Section 112(h)(1) supports establishing a 

work practice standard for D/F in the Boiler MACT, as was done in the recently proposed 

Electric Generating Unit (“Utility”) MACT rule6

. The required tune-ups and other 

emissions reductions in the Industrial Boiler MACT will result in improved combustion 

and minimize conditions conducive to D/F formation without establishing a numerical 

emission standard. 

 One-time stack test data from only 2 units are being used to set D/F limits for the liquid 

subcategory (one of which, SCMillikenDewey, is a unit burning a material available to 

no other unit in the subcategory). Even if the D/F test methods were not being stretched 

beyond their limits, this approach does not provide emissions data representative of the 

normal range of operations and fuel compositions, ambient environmental conditions, 

geographic locations, and other factors that may influence air pollutant emissions. The 

5 For example, Keith, L.H. et al., Principles of Environmental Analysis, Anal. Chem. 1983, 55, 

2210-2218. 

6

 76 FR 24976 
Rubber Manufacturers Association 

July 15, 2011 

Page 6 

performance of the top 12 percent of all units cannot be determined using only a few data 

points. 

 EPA has assigned no costs for compliance with the Boiler MACT D/F standards because 

it is assumed that units will have emissions below detection levels and be able to comply 

with the finalized standards by assigning values of zero to the non-detect congeners. 

While we do not necessarily agree with this assumption for units subject to the lowest of 

the finalized standards, this assumption does suggest that EPA believes that D/F 

emissions from industrial boilers are impossible to measure with high confidence and are 

below detectable levels. 

We offer the following additional data quality comments on the 2 units that are in the liquid D/F 

floor: 

 SCMillikenDewey – D30: Recalculation of the emissions from this unit indicated that 

the test results reported are off by a factor of 1000. Results from the three test runs 

should have been reported as: 

Run 1 3.41E-03 ng/dscm@ 7% oxygen 

Run 2 2.73E-03 ng/dscm@ 7% oxygen 

Run 3 2.74E-03 ng/dscm@ 7% oxygen 

Average 2.96E-03 ng/dscm@ 7% oxygen 

 NYConEd59thStStationNewYork – Boiler 118: Recalculation of the reported emissions 

by the test company indicates the test results were miscalculated. Results for the three 

test runs should have been reported as: 

Run 1 2.05E-03 ng/dscm@ 7% oxygen 

Run 2 1.93E-03 ng/dscm@ 7% oxygen 

Run 3 1.33E-03 ng/dscm@ 7% oxygen 

Average 1.77E-03 ng/dscm@ 7% oxygen 

Summary 

If you have any questions regarding this information, please feel free to contact me at (202) 682-

4836. 

Sincerely, 

Sarah E. Amick 

Environmental Counsel